2000 TMS Annual Meeting Program

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TECHNICAL PROGRAM 12 9 thTMS ANNUAL MEETING & The 129th TMS Annual Meeting & Exhibition EXHIBITION Opryland Convention Center ❈ ❈ ❈ Nashville, Tennessee USA ❈ ❈ ❈ March 12 - March 16, 2000 MONDAY AM

the cost of these increasingly complex materials. This paper will re- AIME/TMS KEYNOTE ADDRESS view some of the work currently being undertaken both at engine

"FutureView...A Look Ahead" manufacturers, and at component suppliers in consortia such as the AM MONDAY Daniel Burrus Engine Supplier Base Initiatives and the Metals Affordability Initia- 11:30am-1:00pm tive. The creation of such consortia to reduce component cost has Convention Center, Presidential Ballroom made significant progress possible in focusing the entire supply chain ✦✦✦ and the customer on this critical issue of affordability Tutorial Luncheon Lecture 8:55 AM Invited "Advanced Rechargeable Batteries: A Materials Science Perspective" Application of Lean Concepts to the Aerospace Forging Value Donald R. Sadoway Stream: Dan Krueger1; Rod Boyer2; David Furrer3; Mary Lee 12:00noon-1:30pm Gambone4; Beth Lewis5; 1GE Aircraft Engines, One Neumann Way, Convention Center, Lincoln C MD H85, Cincinnati, OH 45215 USA; 2Boeing Company, Commercial ✦✦✦ Airplanes Grp., Seattle, WA 98124 USA; 3Ladish Company, Inc., 5481 AIME & TMS Banquet & Awards Presentation S. Packard Ave., Cudahy, WI 53110 USA; 4Rolls-Royce Allison, P.O. 6:00pm Reception Box 420, Indianapolis, IN 46206-0420 USA; 5Wyman Gordon Com- 7:00pm Dinner pany, 244 Worcester St., Grafton, MA 01563 USA Convention Center, Presidential Ballroom Forged components comprise approximately one-third the cost of a propulsion system, and are major cost drivers for airframe systems. +Indicates Student Traditionally, cost reduction efforts have focused on improving individual operations or steps in the value stream. A new U.S. Air Force ManTech program, Forging Supplier Initiative, has been initiated to Advanced Technologies for Superalloy achieve a significant reduction in cost and cycle time through improvements across the entire Supplier-OEM value stream for forged Affordability: Development of New airframe and gas turbine engine components, from raw material order Technology to the finished, ready to install component. Lean Manufacturing, which Sponsored by: Structural Materials Division, High Tem- encompasses a total waste reduction strategy based on a thorough perature Alloys Committee understanding of value for all manufacturing operations in the supply chain, along with forging, machining and modeling technology im- Program Organizers: K. M. Chang, West Virginia Univer- provements, must be exploited to achieve the cost and cycle time sity, Mechanical & Aerospace Engineering, Morgantown, reduction goals. This paper describes the Phase I approach and progress WV 26506 USA; K. R. Bain, GE Aircraft Engines, Cincinnati, in the Forging Supplier Initiative program being performed by the OH 45215 USA; D. Furrer, Ladish Company, Cudahy, WI General Electric-Lean Industrial Forging Team (LIFT) Consortium. 53110 USA; S. K. Srivastava, Haynes International, The objective of Phase I, Analysis and Definition of Cost Reduction Opportunities, is to identify cost and cycle time drivers across the Kokomo, IN 46904 USA entire forged product value stream for representative airframe and propulsion system forgings, and demonstrate the feasibility and pay- Monday AM Room: Canal C off of projects selected to address the major drivers. March 13, 2000 Location: Opryland Convention Center 9:20 AM Invited Cost Modeling of Forged Turbine Engine Disks: Kong Ma1; Session Chairs: Keh-Minn Chang, West Virginia Univer- Kenneth A. Green1; 1Rolls-Royce Allison, P.O. Box 420, Indianapolis, sity, Morgantown, WV 26506 USA; John J. deBarbadillo, IN 46206-0420 USA As a part of the NASA funded IDPAT (Integrated Design/Processing Special Metals Corporation, Huntington, WV 25705 USA Analysis Technology) consortium development program, Rolls-Royce Allison was responsible to develop a cost model for forging and ma- 8:30 AM Keynote chining of turbine engine disks. The objective of this task was to Initiatives for Superalloy Affordability: Malcolm C. Thomas1; develop a geometric feature based software design tool, which can Robert E. Schafrik2; James C. Williams3; 1Rolls-Royce Allison, P.O. assist preliminary design to perform trade-off studies in a qualitative Box 420, Indianapolis, IN 46206-0420 USA; 2GE Aircraft Engines, fashion. The system consists of generic cost related design/manufac- One Neumann Way, MD H85, Cincinnati, OH 45215 USA; 3The Ohio turing rules and allows users to define their company/process specific State University, 477 Watts Hall, 2041 College Rd., Columbus, OH variables associated with these rules. The user can use a graphic user 43210 USA interface to sketch the design section, then the system will report the Modern superalloy forgings and castings have enabled significant cost impact based on the design changes from the base line. increases in turbine engine performance, which have historically been 9:45 AM Invited driven primarily by military requirements. The current situation is ATS Advanced Turbine Airfoil Manufacturing Technology Pro- significantly different, with reduced military budgets for propulsion, gram: Mei Ling Carolyn Henne1; John Brinegar1; Albert Hines1; and increasing demands from both civil and military customers for 1Howmet Research Corporation, 1500 S. Warner St., Whitehall, MI affordable solutions to performance requirements. One result of this 49461 USA shift in emphasis has been the initiation of several programs to reduce 1 The purpose of the Advanced Turbine Airfoil Manufacturing Tech- 11:15 AM Invited nology Program is to develop single crystal and directionally solidified The Castability and Mechanical Properties of Nickel Superal-

MONDAY AM casting technologies to benefit Advanced Turbine Systems (ATS) in- loys Cast Using Thermally Controlled Solidification: Sanjay dustrial and utility gas turbine engines. Traditionally, single crystal Shendye1; M. L. Gambone2; Paul P. Andrews3; Michael Tims4; 1PCC investment casting technologies have been utilized for aircraft gas Structurals Inc., 4600 S.E. Haney Dr., Portland, OR 97206 USA; 2Rolls- turbine blades where yields of 95% and higher are commonly achieved. Royce Allison, P.O. Box 420, Indianapolis, IN 46206-0420 USA; These yields are the result of understanding the relationship between 3Rolls-Royce, plc, P.O. Box 31, Derby DE248BJ UK; 4Concurrent alloy, geometry and process conditions. These relationships have been Technologies Corporation, 1450 Scalp Ave., Johnstown, PA 15904 developed iteratively over the past 30 years. The application of this USA knowledge to Industrial Gas Turbine (IGT) sized castings has demon- Thermally Controlled Solidification (TCS), a casting process pat- strated that the technology involved must be optimized to obtain ented by PCC Structurals, has potential to greatly reduce the cost of similar quality and yields of the smaller aircraft turbine counterparts. aerospace structural castings. The response of three nickel superal- The goal of this program is to develop the technology utilized for IGT loys; INCO 718, INCO 939 and RS5; to casting via TCS was studied as components so that casting yields, furnace up time and direct costs are part of a program supported by the National Center for Excellence in impacted. This presentation will focus on the thermal resistances to Metalworking Technology. (RS5 is a superalloy developed a by Rolls- heat removal from an IGT part. Addressing these resistances to heat Royce, plc.) The alloys were compared by such characteristics as the transfer in a casting process provide guidance on where improvements ability to fill thin-wall sections, propensity to hot tear, and weld can be made. Efforts have been directed toward understanding these reparability. TCS microstructures were analyzed, and mechanical prop- resistances by employing finite-element-modeling (FEM). Modeling erties; including tensile, creep, fatigue and damage tolerance; were has also been utilized to determine the effects of the thermal resis- measured for each of the TCS cast alloys. The castability evaluation tances on typical IGT, single crystal microstructural defects. Addi- plan will be presented in this paper as well as the results and their tional efforts involve benchmarking the state-of-the-art in IGT pro- implication. duction via microstructural and crystal quality evaluations. Freckle and grain-associated defects are also examined in the evaluations. 10:10 AM Break Deformation and Stress During 10:25 AM Invited Spraycast-X for Aerospace Applications: Thomas Tom1; Greg Solidification Butzer2; Kim Bowen3; 1Howmet Research Corporation, 1500 S. Warner Sponsored by: Materials Processing and Manufacturing St., Whitehall, MI 49461-1895 USA; 2Spraycast Technologies Inter- Division, Solidification Committee, Jt. Processing Modeling 3 national, L.L.C., Whitehall, MI 49461-1895 USA; Cannon-Muskegon Analysis & Control Committee, Shaping and Forming Corporation, Muskegon, MI 48441 USA Howmet Corporation has licensed and modified the Osprey, or Committee spray forming process to produce high quality nickel-base superalloys Program Organizers: Brian G. Thomas, University of for gas turbine engine applications. The modified process, known as Illinois, Department of Mechanical and Industrial Engineer- the “Spraycast-X” process, combined vacuum induction melting tech- ing, Urbana, IL 61801 USA; Christoph Beckermann, Univer- nology with high purity argon gas atomization to produce ring and sity of Iowa, Department of Mechanical Engineering, Iowa case preform products. This process yields a product with a fine grain homogeneous microstructure, improved machinability, ability to pro- City, IA 52242 USA; Matthew J.M. Krane, Purdue Univer- cess previously non-forgeable alloys, and an economic benefit that sity, School of Materials Engineering, West Lafayette, IN indicate savings of up to 30% over its ring rolled counterpart. Addi- 47907 USA; Srinath Viswanathan, Oak Ridge National tionally, the Spraycast-X process results in lead-time reductions of Laboratory, Oak Ridge, TN 37831-6083 USA up to 75% over ring rolled components. A description of the process, along with data that substantiates these claims, will be presented. Monday AM Room: Johnson A/B 10:50 AM Invited March 13, 2000 Location: Opryland Convention Center Enhanced Powder Metallurgy (P/M) Processing of UDIMET 720 AE1107C (T406) Turbine Disks: Gary A. Miller1; Kenneth A. Green2; Tony Banik3; Joseph Lemsky4; 1Concurrent Technologies Cor- Session Chairs: Brian G. Thomas, University of Illinois, poration, 1450 Scalp Ave., Johnstown, PA 15904 USA; 2Rolls-Royce Mech. & Industrial Eng., Urbana, IL 61801 USA; Christoph Allison, P.O. Box 420, Indianapolis, IN 46206-0420 USA; 3Special Beckermann, University of Iowa, Dept. of Mech. Eng., Iowa Metals Corporation, 100 Industry Lane, Princeton, KY 42445 USA; City, IA 52242-1527 USA; Matthew J. Krane, Purdue 4Ladish Company Inc., 5481 S. Packard Ave., Cudahy, WI 53110- 8902 USA University, School of Matls. Eng., West Lafayette, IN 47907 Enhanced powder metallurgy (P/M) processing of Udimet 720 has USA been evaluated as an approach for improving the quality, and concurrently, reducing the cost of AE1107C (T406) turbine disks. Enhanced 8:30 AM P/M processing combines several technologies: high-yield production An Experimental Study of the Deformation of a Directionally of fine powder (-270 mesh); low extrusion ratio (3:1) for converting Solidified SCN-ACE Alloy Mush: Ernandes M.S. Rizzo2; Venkatesh as-HIPed material to billets; isothermal forging of disk preforms to Raghavendra1; Houfa Shen1; Christoph Beckermann1; 1University of near-net shape; and selective ultrasonic inspection. Having achieved Iowa, Dept. of Mech. Eng., 2412 SC, Iowa City, IA 52242 USA; acceptable mechanical properties, the viability of this combination of 2Centro Federal de Educacao Tecnologica do Espirito Santo, C.P. 5139, technologies depends upon component performance in cyclic spin and Vitoria, ES 29040-333 Brazil spin burst tests and engine tests as well as verification of projected cost The deformation of a directionally solidified mush of a succinonitrile- savings. Results obtained to date confirm the acceptability of material acetone (SCN-ACE) alloy is studied experimentally. This alloy not produced using this combination of technologies. Technology imple- only solidifies dendritically like a metal alloy, but also has mechanical mentation hinges on the component and engine test results and comple- properties that are similar to those of metals near the melting point. tion of the cost/benefit analysis which remain to be performed. Tech- A test cell was designed that allows for the directional solidification of nology assessment activities including defect migration and flow mod- the alloy and the controlled compression of the mush that forms. eling; residual stress measurement, modeling, and mitigation approaches; Measurements during the deformation include the local displacement HIP modeling; and seeding are discussed. and deformation rate of the solid, the flow patterns in the liquid, temperatures, and liquid concentrations. Results are presented for a 2 range of initial compositions, cooling rates, and deformation amounts. fied yield criterion for porous metals. The measured zero strength The measurements are suitable for validation of future models. The temperature (ZST and zero ductility temperature) (ZDT) were related experiments are relevant, for example, to the deformation of a par- to the solid fractions evaluated by the numerical simulation of tially solidified strand during continuous casting of steel slabs. microsegregation. The characteristic solid fractions of ZST and ZDT which corresponded to 0.75 and 0.99, respectively, were well described 8:50 AM by the prediction equation on ZST and ZDT at given steel composi- Relation Between Tensile and Shear Strengths of the Mushy tions and cooling rates. KEY WORDS: mushy zone; zero strength Zone in Solidifying Aluminium Alloys: Stephen S. Instone1; temperature (ZST zero ductility temperature) (ZDT). Taro Sumitomo1; Arne K. Dahle1; 1The University of Queensland, Dept. of Ming., Mins. and Mats. Eng., Brisbane, Qld 4072 Australia 9:50 AM Break Strength measurements reported in the literature show a significant 10:20 AM deviation in results for semi-solid material tested in shear and in uniaxial A New Hot Tearing Criterion: Application to DC Casting of tension. This therefore raises the question of whether different defor- Aluminum Alloys: Jean-Marie Drezet1; Michel Rappaz1; 1Laboratoire mation mechanisms apply and which are the important with respect to de Metallurgie Physique, Ecole Polytechnique Federale de Lausanne, predicting the formation of various defects, such as hot tearing, sur- MX-G, Lausanne CH-1015 Switzerland face cracking and burst feeding. In this work, the strength develop- AM MONDAY Hot tear is one of the most serious defects which a casting can ment during solidification of various aluminium alloys has been mea- suffer. It represents a major limitation to the production of foundry sured with two different techniques-horizontal tensile testing and di- cast parts and to the productivity of continuous casting processes such rect shear cell testing. The strength results from the two methods as the direct chill casting of aluminum alloys. As an example, the correspond to a much higher degree than suggested by the results casting speed of the direct chill casting of billets is limited for some presented in the literature. Constitutive equations for the mechanical aluminium alloys because of their high propensity to develop hot tears properties of the mushy zone over the whole solid fraction regime, ie. which initiate at non zero liquid fraction at the bottom of the sump. In from coherency to complete solidification, can be developed based on order to predict the occurrence of hot tears in solidifying parts, a hot these strength measurements. These equations can be used for the tearing criterion based on the ability of the interdendritic flow of liquid prediction of stress development as well as defect formation. An im- to compensate for the thermally-induced deformation of the roots of portant component of the analysis of the mechanical properties of dendrites has been recently derived by Rappaz, Drezet and Gremaud. the mushy zone is the fraction of the cross-sectional area that is Based upon a mass balance performed over the liquid and solid phases, capable of supporting an applied load through the formation of a this criterion accounts for the deformation of the solid skeleton per- continuous solid network. Consequently, the formation of solid-solid pendicularly to the growing columnar dendrites and for feeding of the bridges and their contribution to the strength of the mushy zone was interdendritic liquid: it allows the calculation of the maximum strain investigated by comparing mushy zone strength to measurements of rate that the roots of the dendrites can undergo without initiation and/ tensile strength at temperatures just below the solidus temperature. or propagation of hot tears. The present paper gives a summary of the This information was then used to estimate the fraction of the cross- main features and assumptions of the new hot tearing criterion. The sectional area of the mushy zone where solid-solid bridging had oc- equations defining the hot cracking sensitivity index in the particular curred. case a thermally-induced deformation rate which is uniform in the 9:10 AM mushy zone are presented. Then, the model is applied to the particular Tensile Deformation Behaviour at Above Solidus Temperatures case of the DC casting of billets of aluminum alloys. The maximum in Aluminium Alloy 5083: John Anthony Spittle1; Jonathan James1; strain rate sustainable by the mushy zone is derived at the bottom of Stephen G.R. Brown1; Michael E. Keeble1; 1University of Wales, Matls. the sump and in the primary cooling zone. It is demonstrated that the Eng. Dept., Singleton Park, Swansea, Wales SA28PP UK bottom of the sump is more sensitive to hot tearing than the primary A tensile testing technique has been developed specifically for ex- cooling zone, thus limiting the casting speed and therefore the produc- amining true stress/true strain behaviour at above solidus tempera- tivity of the process. tures. ASSET (the Advanced Semi-Solid Elongation Test) applies AC 10:40 AM Joule heating to rapidly reheat specimens from DC-cast ingots to the Application of Solidification-Stress Model to Predict Critical test temperatures. Specimen and grip geometries are designed using a Shell Thickness for Breakouts During Continuous Casting of finite difference thermal model, such that a test temperature is main- Steel: Chunsheng Li1; Brian G. Thomas1; 1University of Illinois, tained at ~+/-2 degrees K over a gauge length of 20mm. Strain mea- Mech. & Industrial Eng., 140 Mech. Eng. Bldg., 1206 W. Green St., surements are carried out using a non-contact linescan camera method. Urbana, IL 61801 USA The fraction liquid at a given test temperature is determined using a During continuous casting, excessive gap formation in the mold can thermodynamic model assuming Scheil non-equilibrium freezing. The lead to a locally thin solidified shell with a higher surface temperature. test has been applied to the study of 5083 aluminium alloy at several This can cause a breakout if the strength of the shell is insufficient to test temperatures and crosshead movement rates. The data has been withstand the ferrostatic pressure at mold exit. A finite element model evaluated and plotted as true stress/true strain and the curves have been has been developed to simulate thermal and mechanical behavior of analysed using a simplex approach. The influences of fraction liquid, the solidifying shell during continuous casting of steel both in and strain rate, strain and microstructure on deformation characteristics below the mold. It features an elastic-viscoplastic creep constitutive are described and discussed. equation that accounts for the different responses of the semi-solid, 9:30 AM delta-ferrite, and austenite phases. The model is applied to predict Mechanical Behavior of Carbon Steels in the Temperature temperature, stress, and strain in a section through the steel shell cast Range of Mushy Zone: Dong Jin Seol1; Young Mok Won1; Tae-jung under conditions that lead to varying degrees of shell growth and Yeo 1; Kyu Hwan Oh1; 1Seoul National University, Matls. Sci. and Eng., surface cooling. At mold exit, ferrostatic pressure is applied and the San 56-1 Shinrim-dong, Lab. of Matls. Deformation and Processing, mechanical response is predicted. The results suggest critical condi- Seoul 151-742 Korea tions that lead to excessive strain and failure of the shell for different Tensile strength and ductility of carbon steels have been measured steel grades. in the temperature range of mushy zone by the in-situ melting tensile 11:00 AM test technique with Gleeble system. The specimen was melted and Cracking Phenomena of AISI 304 Stainless Steel Produced by cooled to the test temperature before the tensile deformation in order Twin Roll Strip Casting Process: D. K. Choo1; S. I. Jeong1; M. J. to get the mechanical properties subject to the continuous casting Ha1; S. H. Kim1; S. Lee2; 1Research Institute of Industrial Science & process. During hot tensile test, a ceramic fiber tube was used to reduce Technology, Strip Casting Project Team, P.O. Box 135, Pohang, the radial temperature gradient in the heated specimen. Tensile strength Kyongbuk 790-600 Korea; 2Pohang University of Science & Technol- of carbon steels in the temperature range of mushy zone increased ogy, Matl. Sci. & Eng., San 31 Hyojadong, Pohang, Kyongbuk 790- with decreasing test temperature, and was well described by the modi- 3 600 Korea Cracks occurring on the surface of AISI 304 stainless steel produced by strip casting process was investigated and the causes for their occur-

MONDAY AM rence were postulated. The sections of as-cast strip near the cracked Dislocations and Microscale Plasticity region were cut and polished to reveal microstructural change, and the cracked region was fractured to investigate the location of crack initi- Modeling: Theory and Modeling of ated area using optical and scanning electron microscopes. The Dislocations fractography showed that the crack was initiated at the tip of dendrite of solidified shell and propagated along the path to the segregated Sponsored by: ASM International: Materials Science liquid film between primary dendrites and the fractured surface was Critical Technology Sector, Materials Processing and heavily oxidized from atmosphere, as this was typical in solidification Manufacturing Division, Structural Materials Division, Jt. cracking at high temperature. The reason for the occurrence of solidi- Mechanical Behavior of Materials, Jt. Computational fication cracking in the strip casting process was uneven stress distri- Materials Science & Engineering bution in the solidified shell during solidification: when the local tensile stress in the delayed solidification region exceeded the critical Program Organizers: Elizabeth Holm, Sandia National strain limit of the shell at high temperatures, the crack would be Laboratories, Albuquerque, NM 87185-1411 USA; Diana formed at delayed solidified shell. The causes for the uneven solidifica- Farkas, Virginia Polytechnic Institute and State University, tion were local heat transfer barriers on roll surface, such as contami- Department of Materials Science and Engineering, nated oxide debris on roll surface, oxide scum entrapped at meniscus Blacksburg, VA 24061 USA; Jeffrey Rickman, Lehigh and melt level fluctuation. The tendency of crack occurrence was also dependent on the chemical composition of molten steel and the cool- University, Department of Materials Science and Engineer- ing rate of the solidified strip. ing, Bethlehem, PA 18105-3195 USA; David J. Srolovitz, 11:20 AM University of Michigan, Department of Materials Science Effect of Gap Distance on the Cooling Behavior and Micro- and Engineering, Ann Arbor, MI 48109 USA; Vaclav Vitek, structure of Indirect Squeeze Cast and Gravity Die Cast 5083 University of Pennsylvania, Department of Materials Wrought Al Alloy: Jong Hyeon Lee1; Hyoung Seop Kim1; Chang Science and Engineering, Philadelphia, PA 19104 USA Whan Won1; Seong Seock Cho1; Byong Sun Chun1; 1Chungnam Na- tional University, Rapidly Solidified Matls. Rsch. Ctr., 220 KungDong, Taejon 305-764 Korea Monday AM Room: Lincoln A An indirect squeeze casting process applied to a wrought Al alloy March 13, 2000 Location: Opryland Convention Center (Al-4.7Mg-0.7Mn) was investigated experimentally and numerically. A two-dimensional finite element computer code for fully coupled Session Chair: Vaclav Vitek, University of Pennsylvania, heat transfer and deformation analysis, ABAQUS, was used to simulate Materials Science & Engineering, Philadelphia, PA 19104 the cooling curves obtained from the experiments. Thermal contraction of the material during solidification creates a cavity between the USA mold and the cooling material. The formation of this cavity is explained using the calculated results. The experimental and predicted 8:30 AM Invited results are discussed in conjunction with the relationships between the Dynamic Simulation of Dislocation Microstructures: Richard cooling rate, microstructure, die geometry and applied pressure. The LeSar1; 1Los Alamos National Laboratory, MST-8, MS G755, P.O. effect of applied pressure on the macrosegregation is also discussed. Box 1663, Los Alamos, NM 87545 USA 11:40 AM One approach to bridge the gap between the atomistic scale and Computer Based Analysis of Thermal Stresses for Continuous macroscopic materials response is a simulation in the intermediate, or Steel Casting Rate Increase: Alexey N. Lozhko1; Viktor M. mesoscopic, regime that focuses on the collective properties of the Olshanski1; Vladimir I. Timoshpolski2; 1State Metallurgical Academy defects. For problems in materials deformation, a promising approach of Ukraine, Thermal Eng. Dept., 4 Gagarin Prosp., Dniepropetrovsk is dislocation dynamics, in which the dynamic motion and patterning UA 320635 Ukraine; 2Byelorussian State Politechnical Academy, 2 of the dislocations themselves are simulate. There are a number of Kondrat Krapiva Str., Minsk BA 220117 Belarus, Republic challenges in implementing dislocation dynamics, including the accu- The maximum increase in continuous steel casting rate is predeter- rate treatment of the long-range interactions, the non-linear-elastic mined by economical reasons. Thermal stresses acting as the factors short-range interactions, etc. We will briefly review progress to date. limiting the process, arise as a result of cooling rate inconsistency We will then present results from a recently-developed three-dimen- between different ingot points. Underestimation of this effect brings sional method for calculating dislocation microstructures based on forth the appearance of inner cracks or residual stresses. By changing Monte Carlo and Kinetic Monte Carlo approaches. The advantages the crystallizer profile it is possible to sufficiently diminish thermal and disadvantages to this approach relative to the more standard dislo- stresses effect on casting rate. The experimental research of thermal cation dynamics simulations will be discussed. Time permitting, we will stresses during solidification is very costly (in Ukraine). That is why present an alternative approach to simulating dislocation microstruc- adequate computer modeling of the process is becoming vital. The tures that yields coarse-grained structures and properties. conjugate 3-D thermo-mechanical state model of the bar-crystallizer 9:10 AM system was the basis of the multi-fold analysis of the process. The Three-Dimensional Dislocation Dynamics Simulations of Stack- paper presents the crystallizer profiles computed for certain occurances ing Fault Tetrahedra Formation using Anisotropic Elasticity: and the results of their experimental implementation. Moono Rhee1; Brian D. Wirth1; James S. Stölken1; 1Lawrence Livermore National Laboratory, Chem. and Matls. Sci. Directorate, P.O. Box 808, L-356, 7000 E. Ave., Livermore, CA 94551 USA The formation of Stacking Fault Tetrahedra (SFT) in Face-Cen- tered Cubic (FCC) metals is studied using both Molecular Dynamics (MD) based on embedded atom method potentials and Dislocation Dynamics (DD) simulations. MD simulations suggest that SFT form via the spontaneous decomposition of Frank partial dislocation loops into stair-rod partial dislocations and Shockley partial dislocations, which subsequently glide to form the SFT; as initially proposed by Silcox and Hirsch. Three-dimensional DD simulations utilizing fully anisotropic elasticity are performed to study the influence of disloca- 4 tion mobility, stacking fault energy, and elastic anisotropy on the potentials of the Finnis-Sinclair type. This comparison enables us to formation mechanism for a variety of FCC metals. This work is per- assess the importance of directional bonding on the dislocation core formed under the auspices of U.S. Department of Energy and Lawrence structure and thus mechanical behavior of the 4d and 5d transition Livermore National Laboratory under contract No. W-7405-Eng-48. metals. This research was supported in part by the Advanced Strategic Computing Initiative of the U.S. Department of Energy through LLNL, 9:30 AM grant no. B331542 (MM and VV). Simulation of Equilibrium Distribution of Dislocation Struc- tures in Bcc Single Crystals under Cyclic Loading: S. B. Biner1; 10:50 AM J. R. Morris1; 1Ames Laboratory, Iowa State University, Metallu. and The Barrier Strength of Mismatch Dislocations: Satish I. Rao1; Ceramics, Ames, IA 50011 USA Peter M. Hazzledine1; 1UES Inc., 4401 Dayton-Xenia Rd., Dayton, Collective motion of large number of discrete edge dislocations in OH 45432 USA bcc single crystals under cyclic loading is investigated using a numerical In order for layered materials to yield, mobile dislocations must be method that combines the finite element method and multi pole ex- able to cross the layer interfaces. The barrier to motion through the pansion algorithm. The dislocations are modeled as line defects in a interface contains several components. In semicoherent multilayers linear elastic medium. At each instant, superposition is used to repre- one of the most significant components is the set of mismatch (van

sent the solution in terms of the infinite-medium solution for the der Merwe) dislocations. The separation of these dislocations, d, de- AM MONDAY discrete dislocations and a complementary solution that enforces the pends on the lattice parameter mismatch and the degree of coherency, boundary conditions. Annihilation of dislocations, generation of new hence on the layer thickness. The barrier stress has two closely related ones and dislocation pinning at obstacles are simulated through a set of parts, first the requirement to bow the mobile dislocation between the constitutive models. The evolution of Bauschinger-effect and harden- mismatch dislocations and second, the requirement to leave a ‘differing and softening behavior is correlated with the cyclic load levels and ence’ dislocation at the interface. The paper describes EAM atomistic the parameters of the constitutive model for the collective behavior simulations designed to test and refine the analytical estimate for this of dislocations. The details of the implementation of the numerical stress of a Gb/d. method for parallel computing in a cluster environment will also be 11:10 AM elucidated. This work was performed for the United States Department Systematic Analysis of Dislocation Junction Reactions in Bcc of Energy by Iowa State University under contract W-7405-Eng-82. Metals Using Anisotropic Elasticity: James S. Stölken1; 1Lawrence 9:50 AM Livermore National Laboratory, Chem. and Matls. Sci. Directorate, Kinetics of Slip and Plasticity Including a Distribution of Ob- P.O. Box 808, L-356, 7000 E. Ave., Livermore, CA 94551 USA stacle Sizes and Load Shedding: Glenn S. Daehn1; 1The Ohio Anisotropic elasticity calculations were performed to estimate the State University, Dept. of Matls. Sci. and Eng., 2041 College Rd., intrinsic strength of dislocation junction reactions in both Group VB- Columbus, OH 43210 USA VIB transition metals, and Iron. A dislocation phase space description Over the past few decades there has been much interest in describing is used to systematically categorize junction formation reactions for plastic deformation as a classical kinetic problem of the thermal acti- dislocations on {110}, {112}, and {123} slip planes: identifying <24 vation of a dislocation over a barrier, where an external stress provides unique junction reactions that comprise the 1176 possible reactions. a driving force tending to push the dislocation over an obstacle. The Regions in which repulsive or neutral dislocation reactions (i.e. jogs) approach almost invariably implicitly assumes that the obstacles are may occur are also identified. The calculations form a critical link of a single uniform size and shape and the driving force at each ob- between microscale phenomena of dislocation interaction and the stacle is also fixed. These are both clear oversimplifications. Presently formulation of mesoscopic models of crystal plasticity by establishing the effects of a spectrum of obstacle sizes as well as slip-induced load a taxonomy of dislocation interactions. The resulting catalog of dislo- shedding will be studied and are shown to produce significant changes in cation reactions indicates the relative strength of dislocation junc- the modeled material behavior. A stochastic cellular automaton model tions, imposes certain symmetry restrictions for physics based hard- is used to construct the model. One of the most exciting aspects of this ening models, and suggests specific latent hardening experiments to approach is that using only very simple and reasonable assumptions measure the influence of junction formation on the work hardening of many commonly-observed creep and plasticity phenomena (such as BCC metals. This work is performed under the auspices of U.S. Depart- anelastic backflow and power-law strain-time creep transients) natu- ment of Energy and Lawrence Livermore National Laboratory under rally emerge and aspects of this behavior can be correlated to the contract No. W-7405-Eng-48. assumptions in a given model. 11:30 AM 10:10 AM Break Primitive Dislocation Loops in Face-Centered Cubic Crystals: Craig S. Hartley1; 1U.S. Department of Energy, Office of Science, SC- 10:30 AM 131, Germantown, MD 20874 USA Study of the Dislocation Cores in Bcc Transition Metals Using The effect of crystal structure on atomic displacements near the Bond-Order Potentials: Importance of Directional Bonding: dislocation core cannot be included in local continuum models of dislo- M. Mrovec1; R. Porizek1; D. Nguyen-Manh2; D. G. Pettifor2; M. Sob3; cations. Atomic models of dislocations using appropriate interatomic V. Vitek1; 1University of Pennsylvania, Dept. of Matls. Sci. and Eng., potentials can provide this information, subject to limitations im- 3231 Walnut St., Philadelphia, PA 19104 USA; 2University of Oxford, posed by the choice of interatomic potential and boundary conditions Dept. of Matls., Parks Rd., Oxford OX13PH UK; 3Institute of Physics on the atomic array surrounding the dislocation line. An intermediate of Materials, Academy of Sciences, Zizkova 22, Brno, Czech Republic approach, the simulation of dislocations by non-local force arrays, The core structure of screw dislocations in the 4d (Nb and Ta) and shows promise as a method for modeling the atomic arrangements 5d (Mo and W) transition metals is studied by computer simulation near dislocations and other crystal defects. This method relies on the using the recently constructed bond-order potentials based on the real- definition of a “primitive dislocation loop”, a non-local continuum space parametrized tight-binding method. In this framework the en- analogue to the infinitesimal dislocation loop of local continuum ergy consists of the bond part that comprises contributions of d elec- theory. The primitive loop consists of an array of forces applied to trons, the central-force many-body part that reflects the environmen- the nearest neighbors of an atom. Magnitudes and directions of the tal dependence of overlap repulsion arising from the valence sp elec- forces are chosen so that the far-field displacement field of the array trons and a repulsive pair-wise contribution; the calculations scale is identical to that of an infinitesimal dislocation loop centered on the linearly with the system size. The potentials have been tested for the atom. The locations of the forces are determined by the crystal struc- accuracy and transferability by evaluating the energy differences of ture of the medium, i.e. by the coordination group surrounding an alternate structures and investigating several transformation paths atom. Dislocation lines can then be constructed by superposition of and comparing these calculations with the ab initio results. The study these primitive loops to form various shapes. Since the singular char- begins with calculations of the gama-surfaces and is followed by simu- acter of the force array is concentrated in the points of application of lations of the structures of screw dislocations. The results are com- the forces, whose displacements can be estimated from atomic force pared with analogous studies made using the central-force many-body 5 constants, there is no singularity in stress or strain at the core of the dislocation. This model has been employed to determine the displace- 8:50 AM ment fields and energies of dislocations, kinks and jogs in the case of Earing Behavior of AA6010 Aluminum Alloy with Different 1 1

MONDAY AM an elastically isotropic, simple cubic lattice, but extension to real Preferred Orientations: Yansheng Liu ; Jiantao Liu ; Xiang-Ming structures relies on the construction of appropriate primitive loops. Cheng1; James G. Morris1; 1University of Kentucky, Light Metals. Such loops have been constructed for the body-centered cubic lattice Resrch. Labs., Dept. of Chem. and Mats. Eng., 117 Anderson Hall, in anisotropic crystals. The present work extends this construction to Lexington, KY 40506 USA the face-centered cubic lattice and describes the technique for deter- Texture inhomogeneity through the thickness has been found in mining properties of finite dislocation configurations. AA6010 aluminum alloy hot band. Annealing does not remove the inhomogeneity but produces different textures. In order to understand 11:50 AM the earing behavior of the materials, samples for earing test were Self-Consistent Modeling of Polycrystal Plasticity: B. Clausen1; prepared by slicing the original hot band in planes parallel to the Carlos N. Tome1; F. Jean-Prost1; M. A.M. Bourke1; 1Los Alamos Na- rolling plane. Samples with the typical texture at the midplane of the tional Laboratory, MST-8, MS G755, Los Alamos, NM 87545 USA hot band and with the textures at the surface of the hot band were The utilization of self-consistent modeling (SCM) of polycrystal- obtained separately. Earing of both the as received samples and an- line plasticity to predict internal and residual stresses in structural nealed samples were measured. The results show that earing of differ- materials has increased significantly in the last decade. The constituent samples and annealed samples were measured. The results show tive equations for elastic-plastic and visco-plastic self-consistent that earing of different samples are typically controlled by their tex- schemes will be presented and the advantages and limitations of the tures. However, earing of the original hot band can not be simply models will be discussed. At Los Alamos National Laboratory the SCM designated as the average of the several sliced samples. of several materials has been correlated with in situ neutron diffraction measurements of internal and residual elastic lattice strains. Further- 9:10 AM more, the SCM scheme has been incorporated into finite element Anisotropy and Texture Evolution of Cold-Rolled Al-Mg Al- codes enabling predictions of complex non-uniform loading and arbi- loys: Seiichi Hirano1; Masaru Nomura1; 1Sumitomo Light Metal Ind., trary geometries. We also discuss the use of SCM as a tool for interro- Limited, Rsch. and Dev. Ctr., 1-12 3-chome, Chitose Minato-ku, gating the microstructural mechanisms, such as type and characteris- Nagoya, Aichi 455-8670 Japan tics of slip and twinning systems, and their interactions. Texture evolution which leads to the earing behavior of a drawn cup of cold-rolled Al-Mg alloy sheet was investigated by two different process materials, with and without intermediate annealing during cold rolling. The samples without intermediate annealing had 6 or 8 ears on General Abstracts: Aluminum and the cups, while ones with intermediate annealing had 4 ears. Ears at 0° and 180° to the sheet rolling (RD) are related to the intensity of the Texture Cube and RD rotated Cube texture. 45° ears were related to beta fiber Sponsored by: TMS components of the rolling texture, and the ratio of Brass and Cu Program Organizers: Mark E. Schlesinger, University of component intensities along the beta fiber was different between with Missouri, Department of Metallurgical Engineering, Rolla, and without intermediate annealing samples. Texture and microstructure changes associated to the intermediate annealing conditions are MO 65409-0001 USA; Alton T. Tabereaux, Reynolds Metals also discussed. Company, Smelter Technology Laboratory, Muscle Shoals, 9:30 AM AL 35661-1258 USA; Dan J. Thoma, Los Alamos National Analysis of Tensile/Compressive Deformation in Zirconium Laboratory, Materials Science and Technology, Los Alamos, Bent Beams: G. C. Kaschner1; T. A. Mason1; J. F. Bingert1; P. J. NM 87545-0001 USA; Patrice E.A. Turchi, Lawrence Maudlin1; 1Los Alamos National Laboratory, Los Alamos, NM 87545 Livermore National Laboratory, Materials Science and USA Technology Division, Livermore, CA 94551 USA Previous work has demonstrated that the deformation mechanisms of this highly anisotropic low-symmetry metal may be dominated by either slip or twinning depending on strain rate, temperature, and Monday AM Room: Knoxville A orientation. In the current study, we have loaded basal fiber textured March 13, 2000 Location: Opryland Convention Center zirconium beams of two orientations in 4-point bending to produce a continuous stress-strain gradient across the thickness of the sample. Session Chair: Mike O’Brien, Lawrence Livermore National The macroscopic shape of the cross-sections was used to validate predictive modeling efforts. The predictive modeling is based on an Laboratory, Livermore, CA 94551 USA anisotropic yield criterion that is a function of texture and deformation mechanism, ie., slip or twinning. Automated EBSP methods were 8:30 AM used to analyze twinning deformation modes as a function of position, Comparison of Microstructure and Texture of AA3XXX Direct and hence sign and magnitude of strain, in the beam. These measure- Chill Cast Ingot and Strip Cast Slab: J. T. Liu1; Y. Liu1; J. G. ments corroborated the basis for constructing our yield function. Re- Morris1; 1University of Kentucky, Light Metals Resrch. Labs., Dept. search supported by the US DOE, Basic Energy Sciences, Division of of Chem. and Mats. Eng., 177 Anderson Hall, Lexington, KY 40506 Materials Sciences. USA 9:50 AM Direct chill (DC) ingot and strip cast (SC) slab present significantly The Cooling and Solidification Behaviour of Aluminum and different features in microstructure and texture. Both the microstruc- Aluminum Alloys Weld: Kimioku Asai1; Eisaku Tokuchi1; 1Musashi ture and texture of AA3105 DC ingot and AA3015 SC slab were ob- Institute of Technology, Tokyo, Japan served in this work for the purpose of determining the difference in Experiments on weld solidification were successfully carried out in microstructure and texture between DC ingot and SC slab. The results TIG arc spot welding of thin plate. This second research was conducted show that both the DC ingot and SC slab present a random texture and to establish a practical, convenient method for evaluating the hot nearly the same grain structure, however, the dispersion of particles cracking susceptibility in Al-alloys weld. In addition to the tempera- and the solute supersaturation condition of the alloying elements for ture measurement in welding thermal cycle, the behaviour of the liquid DC ingot and SC slab are very different. Consequently, the dispersion film solidifying in the grain boundary was investigated by revealing of particles and the solute supersaturation condition of the alloying dynamically the liquid films in breaking surfaces with a newly devel- elements significantly contribute to the great difference in micro- oped high-speed breaking machine, and by observing them prudently structure and texture evolution between DC ingot and SC slab in the with SEM. All those results including on solidification rate, cooling following thermomechanical processing of these materials. rate, temperature gradient, and fraction solid were quantitatively gath- 6 ered in a diagram named CCSP (Continuous Cooling Solidification electrocoats features texture-related effects of anisotropy of substruc- Process) diagram. The result of the Varestraint Test carried out to ture and nonhomogeneity of granular structure. make hot cracking occur was also considered with the same diagram. This series of operation enabled us to discuss the cooling and solidification behaviour of weld in relation to the hot cracking susceptibility. 10:10 AM Break General Abstracts: Ferrous and 10:30 AM Refractory Metals Fatigue Crack Initiation in Aluminum Alloys: Peter S. Pao1; Sponsored by: TMS 1 1 1 Steven J. Gill ; Jerry C. Feng ; Naval Research Laboratory, Washing- Program Organizers: Mark E. Schlesinger, University of ton, DC 20375 USA Fatigue crack initiation from pre-existing corrosion pits of 7075 Missouri, Department of Metallurgical Engineering, Rolla, and 7050 alloys was investigated using blunt-notched WOL specimens. MO 65409-0001 USA; Alton T. Tabereaux, Reynolds Metals The presence of corrosion pits not only reduces the fatigue crack Company, Smelter Technology Laboratory, Muscle Shoals, initiation lives but also lowers the fatigue crack initiation thresholds AL 35661-1258 USA; Dan J. Thoma, Los Alamos National AM MONDAY by half. The effect of aging was studied by comparing the fatigue crack Laboratory, Materials Science and Technology, Los Alamos, initiation of peakaged 7075-T651 to that of overaged 7075-T7351. At high stresses, 7075-T651 exhibits longer fatigue initiation lives NM 87545-0001 USA; Patrice E.A. Turchi, Lawrence than does 7075-T7351. However, at lower stresses, the difference Livermore National Laboratory, Materials Science and between the fatigue crack initiation diminishes. The effect of orienta- Technology Division, Livermore, CA 94551 USA tion was investigated by comparing the fatigue crack initiation of SL 7075-T651 to that of ST 7075-T651. At high stresses, SL 7075- Monday AM Room: Canal A T651 demonstrates longer fatigue initiation lives than does ST 7075- T651. Again at lower stresses, such differences disappear. Fatigue crack March 13, 2000 Location: Opryland Convention Center initiation and identification of initiation sites and mechanisms are discussed. Session Chair: George Spanos, Naval Research Laboratory, 10:50 AM Washington, DC 20375-5000 USA Improvements of 6063 Al-Alloy for Rapid Extrusions and Pos- 1 1 sibility of Reducing Their Tails: Abdel Haleem Ghaneya ; Assiut 8:30 AM University, Mining and Metallu. Dept., Egypt Measurement of Burst Disc Properties Using Nanoindentation: This study was applied on an industrial scale of EgyptAlum Com- Neville R. Moody1; Steven L. Robinson1; Mike Chiesa1; 1Sandia Na- pany It is principally divided into two main branches. The first is tional Laboratories, P.O. Box 969, MS9403, Livermore, CA 94551- concerned with the transformation of beta phase into alpha phase, and 0969 USA at the same time, the dissolution of Magnesium silicide precipitate. Stainless steel burst discs are used in many high hydrogen pressure Both processes lead to ease the fabricability of the alloy by extrusion, applications to insure safe operation. These discs are formed to a even at a rapid rate. The second branch deals with the possibility of dome-like geometry and scored to produce a thin-walled, high strength reducing ingot tails. Manufacturers require ingots of 6063 free of non- ligament beneath the score. However, little is known about how struc- metallic inclusions of both ends. Our trial was carried out to achieve ture and properties in this ligament control burst pressure. As a conse- minimum non-metallic inclusions number and size, as well as their quence we used nanoindentation to measure properties and finite ele- distribution per unit area at both ends of ingot. According to the first ment analysis to map stresses and strains in a 316L burst disc. The ° branch, the temperature of homogenization was found to be 580 C for nanoindentation results showed a more than two-fold increase in holding time of 12 hours. This is sufficient for obtaining the alpha strength due to scoring in good agreement with finite element results phase and for the dissolution of Magnesium silcide precipitate. Cool- obtained using a strain hardening relationship to describe stresses in ing was performed by using three fans, each providing 60000 meter 316L. These results strongly suggest that the burst pressure is con- cube of air per hour. By this specific cycle (heating, holding, cooling), trolled by dislocation interactions. The test techniques and results will the beta phase transformation and magnesium silicide precipitation be discussed and used to show how a materials and mechanics approach and its coalescence are prevented. As for the second branch, our trials can provide accurate measures of small volume properties. give inconsistent results. Nevertheless 20% of the removed part can be saved. 8:50 AM Void Nucleation at Inclusions in Ultra-High Strength Steels: 11:10 AM Luana E. Iorio1; Warren M. Garrison1; 1Carnegie Mellon University, Characterization of Oriented Structure in Copper Electrocoat- Dept. of Matls. Sci. and Eng., Pittsburgh, PA 15213 USA 1 1 2 ings: Yuliya O. Proshenko ; Evgenii P. Kalinushkin ; Oleg B. Girin ; We have investigated the effects of carbon content on the strength 1 State Metallurgical Academy of Ukraine, Dept. of Phys. Metallu., and toughness of AF1410 type steels when the sulfur has been gettered 2 Prospekt Gagarina 4, Dnipropetrovsk 320635 Ukraine; Ukrainian as either chromium sulfide or as titanium carbosulfide. After temper- State University of Chemical Engineering, Dept. of Matls. Sci., Prospekt ing at 510°C for five hours the yield strengths were about 1500MPa, Gagarina 8, Dnipropetrovsk 320005 Ukraine 1600MPa and 1710MPa for carbon levels of 0.16, 0.20 and 0.25wt.%, A comprehensive study into structure evolution in copper electro- respectively. At a carbon level of 0.16wt.% the Charpy impact energy lyte coatings at the stages of nucleation and growth of the major is about 180J when the sulfur is gettered as particles of titanium component of texture was carried out using nonconventional X ray carbosulfide and about 100J when the sulfur is gettered as particles of diffraction techniques in combination with scanning electron micros- chromium sulfide. As the carbon and yield strength increase the tough- copy and electron probe analysis. Following thermodynamic consider- ness decreases much more rapidly when the sulfur is gettered as tita- ations were found to exert dominating influence on texture formation nium carbosulfide than when the sulfur is gettered as chromium sulfide in copper electrocoats, namely grain boundary energy alone at the which could be due to the void nucleation resistance of the titanium nucleation stage, and grain boundary energy on equal terms with bulk carbosulfide particles decreasing with increasing matrix strength while energy at the grain growth stage. Anisotropy of oriented structure was the particles of chromium sulfide have low resistance to void nucle- observed even at the texture formation onset and involved not only ation resistance at all strength levels. In this work the void nucleation element size but also element shape. Thus for the major component resistance has been determined for titanium carbosulfide and chro- the nuclei height was almost four times greater than the average of the mium sulfide particles at strength levels ranging from about 1500MPa two other dimensions. A comprehensive analysis of evolution of tex- to 1710MPa. This work was funded by the Division of Materials ture, substructure, microstructure and surface morphology in the course Research of the National Science Foundation. 7 of copper layer growth revealed that the oriented structure of copper 9:10 AM tion with microscopic observations, and were correlated with impact Use of Metallic-Glasses in MoSi2-Stainless Steel Joining: toughness. Specimens with the peak temperature raised to 1350°C Rajendra U. Vaidya1; Partha Rangaswamy1; 1Los Alamos National ° MONDAY AM showed mostly martensite. With the peak temperature raised to 900 C, Laboratory, MST-6, MS G770, Los Alamos, NM 87545 USA the martensite fraction was reduced, while bainite or martensite island Residual stresses due to mismatch in elastic and thermal expansion were formed because of decrease in a prior austenite grain size and the properties in ceramic-metal joints can lead to failure at the interface slow cooling rate from the lower austenite region. As the martensite or within the brittle ceramic. Low temperature brazing techniques fraction increased, hardness and strengths tended to increase, whereas coupled with ductile interlayers alleviate this problem. However, the impact toughness decreased. However, impact toughness of the sub- use of precious metal based brazes and the incorporation of the critical HAZ with the peak temperature raised to 650°C-700°C was interlayer add to the complexity and cost of the joining process. We seriously reduced after post-weld heat-treatment (PWHT) since car- have overcome these problems with the use of metallic-glass brazes. bide particles were of primary importance in initiating voids. This is a new idea that eliminates the need for separate interlayers in ceramic-metal joining. We present the results of our preliminary join- 10:50 AM 1 1 ing experiments using metallic-glasses. Stainless steel 316L and mo- Nanocomposite Magnets: D. J. Branagan ; Bechtel BWXT Idaho lybdenum disilicide were successfully brazed using a cobalt based metal- LLC, Idaho Nat. Eng. and Environ. Lab., 2351 N. Blvd., Idaho Falls, lic glass. Issues pertaining to the interfacial chemistry, joint strength ID 83415-2218 USA and residual stresses are presented here. The realization of high energy densities in permanent magnetic materials requires careful control of both the composition and the 9:30 AM processing conditions in order to develop appropriate microstructures Stress-Rupture Strength and Creep Behaviour on Molybde- capable of storing high energy densities. It will be shown that nanoscale num-Rhenium Alloys: Bernd Fischer1; Dietmar Freund1; Samantha metal matrix composite microstructures can be developed in modified Baxter1; Jan-C Carlen2; Todd A. Leonhardt2; 1Fachhochschule Jena, Nd-Fe-B alloys by careful selection, manipulation, and control of the Dept. of Matls. Tech., Univ. of Appl. Sci., Jena D-07745 Germany; alloying elements. The development of composite microstructures in 2Rhenium Alloys Inc., P.O. Box 245, Elyria, OH 44036-0245 USA hard magnetic materials is a novel approach resulting in many benefi- Due to the outstanding properties of molybdenum and rhenium, cial effects on the resulting structure/processing/property relation- which have very high melting points and excellent strength at el- ships evated temperatures, molybdenum-rhenium alloys are valuable materials in applications where high strength at high temperature is required. The manufacturing processes of Mo-Re alloys can be tailored so as to enhance the mechanical properties of the part. The design engineer and manufacturer need exact information on the creep be- General Abstracts: Materials havior, and stress-rupture strength at elevated temperatures. After an extensive literature search of the technical literature, relatively few Processing and Fundamentals reports were found on the mechanical properties of molybdenum- Sponsored by: TMS rhenium alloys, so an investigation was set forth using a special test Program Organizers: Mark E. Schlesinger, University of facility for measuring high melting materials at temperatures up to Missouri, Department of Metallurgical Engineering, Rolla, 3273K under a protective atmosphere. The stress-rupture diagrams MO 65409-0001 USA; Alton T. Tabereaux, Reynolds Metals were determined for the molybdenum-rhenium alloys with rhenium contents between 41 and 51 weight percent at test temperatures of Company, Smelter Technology Laboratory, Muscle Shoals, 1473K, 1873K and 2273K at 0.1 to 10 hours creep rupture times. AL 35661-1258 USA; Dan J. Thoma, Los Alamos National Laboratory, Materials Science and Technology, Los Alamos, 9:50 AM Effect of the Carbide Solution Heat Treatment of ASTM-75 NM 87545-0001 USA; Patrice E.A. Turchi, Lawrence Alloys on the Wearing Behavior of the UHMWPE Material: Livermore National Laboratory, Materials Science and Edgar Guerra Martinez1; H. M. Mancha1; A.J. U. Perez2; H. Lopez3; Technology Division, Livermore, CA 94551 USA 1Centro de Investigacion y Estudios Avanzados del IPN, Tribology, Carr. Saltillo-Monterrey Km 13, P.O. Box 663, Saltillo, Coahuila 25000 Monday AM Room: Canal E Mexico; 2Universidad Autonoma de Nuevo Leon, Monterrey, NL; 3Uni- versity of Wisconsin, Milwaukee, WI USA March 13, 2000 Location: Opryland Convention Center Today, one of the most important problems that face metallic hip and knee prostheses researching is the wear of polymeric and metallic Session Chair: A. K. Vasudevan, Office of Naval Research, materials used manufacture orthopedic implants to rehabilitate pa- Code 332, Arlington, VA 22217-5660 USA tients with no longer functional joints. The aim of this researching work was to study the effect of some surface modifications on an ASTM-F75 alloy on the wear rate of UHMWPE in order to decrease 8:30 AM the amount of particles produced by sliding of the metal against the Experimental Comparison of the Intrinsic Jump Frequency polymer. The desired amount of particles being that which can be Formalism with the Traditional Darken-Manning Formalism removed via the patient lymphatic system. To study the wear proper- for Describing Diffusion in Cu-Ni-Zn: Robert T. DeHoff1; Nagraj ties, specimens of ASTM-F75 alloy were prepared by precision invest- Kulkarni1; 1University of Florida, Dept. of Matls. Sci. and Eng., ment casting process, surface treated, and tested against UHMWPE at Gainesville, FL 32611 USA 37°C, applying two types of lubricant solutions (distilled water and Earlier presentations derived the following expression for the in- Ringer solution). trinsic flux of component k in a multicomponent system: where Ck is the molar concentration of component k, ÿk is the composition de- 10:10 AM Break pendent jump frequency of component k determined in a tracer diffu- 10:30 AM sion experiment, ÿ is the jump distance and ÿk is a factor that reports Microstructure and Impact Toughness of Heat Affected Zones the extent to which the atom jumps are biased. All of the information of an SA 508 Steel: Sangho Kim1; Sunghak Lee1; Soon Ju Kwon1; Joo in this equation is determinable from independent experiments except Hag Kim2; Jun Hwa Hong2; Nack Joon Kim1; 1Pohang University of ÿk. The traditional Darken-Manning approach to the description of Science and Technology, Matls. Sci. and Eng., San 31 Hyoja-dong, multicomponent diffusion uses tracer diffusion coefficients, thermo- Nam-gu, Pohang, Kyoungbuk 790-784 Korea; 2Korea Atomic Energy dynamic information and a contribution derived from the vacancy Research Institute, Nuclear Matls.Tech. Dev., Dajeon 305-600 Korea wind effect to compute intrinsic diffusion coefficients in the phenom- In this study, microstructures of a heat affected zone (HAZ) of an enological description of the diffusion process. In this presentation SA 508 steel were identified by Mossbauer spectroscopy in conjunc- these two disparate descriptions have been used to compute the ex- 8 perimental observables in a diffusion experiment (composition paths 9:50 AM and profiles, Kirkendall shifts) for the system Cu-Ni-Zn. A simulation Thin Film Coated Glass Soldering: F. Michael Hosking1; 1Sandia based upon these sets of equations permits separate computation of National Laboratories, Dept. 1833, P.O. Box 5800, MS0367, Albu- the experimental observables with each of the various influences as- querque, NM 87109-0367 USA sumed to operate in each formalism. This allows a definitive assess- Conductive adhesives and solders are generally used to join soda- ment of the effect that each of these factors has in predicting the lime glass to itself and other materials. Soldering usually requires met- experimental observables and a definitive comparison of the two ap- allization of the glass. Two thin film glass coatings, Cr-Pd-Au and Cr- proaches. Ni-Sn, were investigated. Glass-to-glass test specimens, metallized with Cr-Pd-Au and soldered with 60Sn40Pb solder, had shear strengths ap- 8:50 AM proaching 16.5 MPa. Similar Cr-Ni-Sn coated specimens gave higher Asymptotic Decay Analysis of Phase Coarsening Data: Steven strengths, 20-22.5 MPa, with failures primarily in the glass. Surface P. Marsh1; 1Naval Research Laboratory, Code 6325, 4555 Overlook roughness of the glass pieces also affected the coating uniformity and Ave. SW, Washington, DC 20375-5343 USA bond strength. Solder wetting and shear test results are discussed. The The progress of phase coarsening is generally quantified by the work was conducted at Sandia National Laboratories, a multiprogram increase in the average particle size. However, coarsening is essen- laboratory operated by Sandia Corporation, a Lockheed Martin Com- tially a relaxation process driven by a reduction in the excess interfa- AM MONDAY pany, for the United States Department of Energy under Contract DE- cial energy of a multiphase structure. Analysis of coarsening data via AC04-94AL85000. the decay of a global property, such as specific surface area, introduces a non-arbitrary temporal parameter that relates the experimental clock 10:10 AM to an asymptotic time scale. This approach permits the fitting of data Preparation of Silica Fibers from a Suspension: Hiroyuki at earlier times, where the driving force is greatest, and more accurate Nakamura1; Akira Shimizu2; Yoko Suyama2; Eiichi Abe1; Noriyuki determination of the power-law rate constant. Implications of this Yamada1; 1Kyushu National Industrial Research Institute, Dept. of approach on measurement and interpretation of coarsening kinetics Inorganic Matls., 807-1, Shuku, Tosu, Saga 841-0052 Japan; 2Shimane will be discussed. University, Dept. Matl. Sci., 1060, Nishikawazu, Matue, Shimane 690- 8504 Japan 9:10 AM + Fibrous silica was prepared by drying silica particle suspension. The Microstructural Evolution of Solid-Liquid Mixtures: Victoria A. silica fibers were obtained only on walls, which were wetted well by the Snyder1; Jens Alkemper1; Peter W. Voorhees1; 1Northwestern Univer- suspension. The fibers were made of roughly close-packed silica par- sity, Matls. Sci. & Eng., 2225 N. Campus Dr., Evanston, IL 60208- ticles. Widths of the fibers were affected by some preparation condi- 3108 USA tions. In this study, wider fibers were obtained under these conditions: The coarsening of solid Sn particles in a Pb-Sn eutectic liquid was higher silica particles concentration, larger particle diameter, and lower studied under microgravity conditions during the Microgravity Science drying temperature. From an observation of a generation of fibers, the Laboratory-1 mission. A clustered structure of particles exists at the formation mechanism was considered as following; When a dispersion beginning of the experiment for samples containing 10% and 20% of silica was dried, a silica film made of silica particles were generated volume fractions of coarsening phase. The coarsening of such a clus- on a wall. During drying, since the shrinkage ratio of the film depends tered structure of particles was studied via numerical simulations of on the distance from the surface of the suspension, stress whose direc- coarsening using the approach developed by Akaiwa and Voorhees. tion is parallel to the suspension surface arises. Because of the hori- Theoretically predicted particle size distributions and spatial correla- zontal stress, the cracks are considered to proceed to the downward to tion functions will be directly compared to the results from the space- generate silica fibers. flight experiment. Furthermore, the microstructure in samples containing 50% and 70% coarsening phase (where a percolated structure 10:30 AM Break of particles is present) was examined in orientation space using orien- 10:50 AM tation imaging microscopy. Electron back-scattered diffraction pat- Formation of Cu-Ni-Zr Amorphous Powders with Significant terns were used to determine the misorientation between contacting Supercooled Liquid Region by Mechanical Alloying Technique: particles as well as the evolution of the misorientation distribution Pee Yew Lee1; Chung Kwei Lin2; G. S. Chen2; 1National Taiwan Ocean function with coarsening time. University, Instit. of Matls. Eng., 2 Pei-Ning Rd., Keelung 202 Tai- 9:30 AM wan; 2Feng-Chia University, Matls. Sci., Taichung 400 Taiwan Elevated Temperature Mechanical Properties and Microstruc- Recently, the studies on amorphous alloys were focused on the ture of a Ag-Cu-In-Ti Active Metal Braze Alloy: John J. Stephens1; formation of bulk amorphous with a distinct supercooled liquid regions Thomas E. Buchheit1; 1Sandia National Laboratories, Matls. Joining by using the traditional melt quenching technique, even water quench- Dept., P.O. Box 5800, MS0367, Albuquerque, NM 87185-0367 USA ing are quite active. However, the composition of the material for the Commercial Ag-Cu-In-Ti active metal braze alloys such as Incusil production of bulk amorphous alloys by quenching method is limited ABA (TM of WESGO Metals, Inc.) are attractive for metal-ceramic by the necessary low cooling rate. Changes in composition, therefore, brazing applications because they eliminate the need for metallization strongly affect the glass forming ability and hence the required cooling of the ceramic and have relatively low braze process temperatures rates to obtain bulk amorphous samples. In comparison to quenching (~750°C). We have studied the elevated temperature mechanical prop- techniques, amorphization by mechanical alloying process offers an erties of Incusil ABA using compression testing over the temperature alternative way which might be a promising method for the formation range 150-550°C. For the case of constant load creep data, the mini- of a bulk amorphous with an obvious supercooled liquid region through mum strain rate as a function of stress and temperature can be repre- the powder metallurgy route. In this study, we have investigated the sented by the Garofalo sinh equation. Based on compressive stress- possibility of preparing amorphous Cu-Ni-Zr powders by mechanical strain results, the 0.2% offset yield stress and work-hardening slope alloying. The results indicated that several amorphous alloy samples for this alloy are observed to have a maximum in the temperature were found to exhibit a wide supercooled liquid region before crystalli- range of 100-150°C. This effect is discussed in view of the microstruc- zation. This is believed to be the first evidence for the appearance of ture of this alloy, which contains a significant volume fraction of a supercooled liquid region for mechanically alloyed Cu-Ni-Zr amor- Cu2InTi ordered intermetallic compound. Low force nanoindentation phous powders. The origin of the significant supercooled liquid region test results will be presented which quantify the relative hardness of of these new alloys is discussed. this phase compared to the Cu-rich phase and the Ag-rich matrix of 11:10 AM this braze alloy. Sandia is a multiprogram laboratory operated by Sandia A Thermodynamic Model for Mechanical Alloying: Saheb Corporation, a Lockheed Martin Company, for the U.S. Dept. of Nouari1; Abdul Razak Daud1; Shahidan Radiman2; Redzuwan Yahaya2; Energy under contract DE-AC04-94Al85000. 1University Kebangsaan Malaysia, Dept. of Matls. Sci., Faculty of Physical and Appl. Sci., Bangi, Selangor 43600 Malaysia; 2University 9 Kebangsaan Malaysia, Dept. of Nuclear Sci., Faculty of Physical and Appl. Sci., Bangi, Selangor 43600 Malaysia

MONDAY AM Mechanical alloying is a useful technique to produce different mate- General Non-Ferrous Pyrometallurgy: rials. Despite it’s importance a few attempts has been made to model Industrial Operations and Recycling the fundamental process on one hand and to explain thermodynamically the mechanism of mechanical alloying on the other hand. In the Sponsored by: Extraction & Processing Division, Pyromet- present study, an attempt to develop a thermodynamic model for solid allurgy Committee solution formation by mechanical alloying is presented. The main Program Organizers: Robert L. Stephens, Cominco objective of the work is to describe from a purely thermodynamic Research, Trail, British Columbia V1R 4S4 Canada; Pekka point of view the evolution of solution during mechanical alloying Taskinen, Outokumpu Research Oy, Pori FIN-28101 Finland based on the regular solid solution model, taking in to account the energy rise during alloying due to the generation of different defects. Monday AM Room: Bayou B 11:30 AM March 13, 2000 Location: Opryland Convention Center A Study of Casting Filling Process Using Simulation Tools: Pongsakd Dulyapraphant1; Patcharin Poosanaas1; Supparit Lounkosonchai1; Harit Sutabutr1; Panya Srichandr1; 1National Metal Session Chair: Robert L. Stephens, Cominco Research, and Materials Technology Center, Manufacturing and Design Tech. Trail, British Columbia V1R 4S4 Canada Ctr., 9th Floor, Gypsum Metropolitan Bldg., 539/2 Sri-Ayudhya Rd., Bangkok 10400 Thailand The application of computer simulation are being widely used and 8:30 AM becoming extremely beneficial in improving casting process and in The Use of Ausmelt Technology at the Minsur Tin Smelter and 1 2 1 tooling design. The use of simulation provides an insight into how Refinery: Colette M. Ng ; Ken R. Robilliard ; Ausmelt Limited, 12 2 each process related parameters affecting the quality of the casting. In Kitchen Rd., Dandenong, Victoria 3715 Australia; Funsur S.A., KM this study, the influence of filling process on the quality of casting will 240 Panamericana Sur, Pisco-Ica, Peru be investigated by using a casting simulation package. Different types The Peru-based tin mining company, Minsur S.A., commissioned of gating systems will be simulated in order to identify how each Ausmelt Limited to design, supervise construction, and commission a component of the gating system contribute to the filling process. The tin smelter and refinery for production of refined tin metal. The plant comparison between simulation results and experimental results will be is located 240 km south of Lima, near Pisco, Peru, and is operated by presented in order to verify the simulation results. Furthermore the Funsur S.A., a wholly-owned subsidiary of Minsur. Selection of Ausmelt use of simulation results to detect some flow related defects will be Technology followed a series of crucible scale test work and pilot plant studied as well. trials conducted at Ausmelt’s facility in Dandenong, Australia and two feasibility studies undertaken by Ausmelt in 1991 and 1993. Ausmelt 11:50 AM began the plant design in 1994 with the construction phase following The Story of the Safety Related Problems in the Titanium In- in 1995. Commissioning of the plant commenced early in 1996 with a dustry in the Last Millennium: Eldon R. Poulsen1; 1TI + MG Phase 1 target throughput of 30,000 tonnes per annum of concen- Consultant, 4360 Malaga Dr., Las Vegas, NV 89121 USA trates. In mid-1998, oxygen enrichment of the Ausmelt lance air was The titanium industry dates back to the turn of the century. The introduced to expand the capacity to the Phase 2 throughput of 40,000 actual commercial production of the metal actually started in about tonnes per annum of concentrates. The process route involves the use 1950. By the end of the century, the industry was producing at the rate of an Ausmelt furnace for primary concentrate smelting, followed by of over 100-million pounds per year. From a safety standpoint, the a conventional tin pyro-refining circuit to produce high-grade tin best judge of the industry is to evaluate each of the fatalities that have suitable for sale. Further work continues between Ausmelt and Funsur been experienced during the last 50 years. These as well as other major to investigate the use of an alternative, more economical fuel source safety related problems such as fires will be discussed. Early on the and the installation of a second Ausmelt furnace. This paper reviews problems was lack of knowledge with regards to furnace design and the project to date with details of ongoing operations and develop- related explosions. The knowledge at the time was based on steel ments at the Minsur Tin Smelter. technology. The addition of the problem of hydrogen explosions was a totally new problem. When molten titanium reacts with water, the 8:55 AM water breaks down and liberates the hydrogen which results in major Treatment of Industrial Waste in Reverberatory Furnace at 1 1 explosions. During the first 5 years of the industry, furnace explosions Onahama Smelter: Takayuki Sato ; Nobuo Kikumoto ; Kiyotaka 1 1 1 killed a total of 6 employees. The next problem that plagued the Abe ; Michio Nishiwaki ; Onahama Smelting & Refining Company industry was that of fires and explosions from sponge and fines fires. Limited, Smelting, 1-1 Nagisa Onahama, Iwaki, Fukushima 971-8101 Fines fires and explosions killed a total of 3 employees. The third Japan problem was confined space entry. Fatalities resulted from argon, ni- Recently, the treatment of industrial waste materials has been a trogen, and other inert gases. A total of 5 fatalities have been recorded serious social problem here in Japan. Landfilling is now strictly prohib- to date from these causes. This paper discusses each of the fatal inci- ited due to a limited land area and incineration method is also regulated dents and explains the cause and effect. Safety committees were formed so as to not generate dioxins and furans (DXN). With this background, and safe operating equipment and procedures were developed. Three Onahama Smelter has begun to treat automobile shredder dust in rever- separate lists of safety recommendations are included, var furnace beratory furnaces to recover various metals such as copper, gold, silver design and operation, handling and storage of titanium fines and sponge and palladium without generation of DXN. The total volume of these and confined space entry based on OSHA standards. dusts is expected to be more than 1 million metric tonnes a year in Japan. Onahama Smelter is now planning to treat about 20% of them in the near future by using tonnage oxygen. In this paper, the heat balance and control method of DXN in reverberatory furnaces and treatment of these dusts are described. 9:20 AM Precursors for PCDD/F Formation During Combustion of Elec- tronic Scrap: Menad Nourreddine1; 1Luleå University of Technol- ogy, Div. of Process Metallu., Luleå Se-97187 Sweden The flame retardant contained in the electronic scrap can form dioxins (PCDDs) and furans (PCDFs). Their formation can be dependent on the quantities of carbon, hydrogen, chlorine, and oxygen present in a given system, as well as on parameters such as temperature 10 and pressure. Inadequate supply of combustion air (incomplete oxida- 11:15 AM tion), low combustion temperatures (incomplete combustion), and Reversing the Philosopher’s Stone: Recovering Iron from Cop- insufficient turbulence in the combustion are factors which can favour per Slags and Residues (Adeptus Ineptus): Larry M. Southwick1; their formation. Dioxins and furnans were also produced calatytically 1L. M. Southwick and Associates, 992 Marion Ave., Ste. 306, Cincin- from chlorinated phenol precursors, non-chlorinated compounds that nati, OH 45229 USA were chemically modified, and reaction of phenol with inorganic chlo- Interest has been expressed over the years in recovering iron from ride. In this paper, different precursors such as combinations of C, H, copper smelting and leaching residues. In the United States, this inter- O, Cl, rapid formation/combustion intermediates, and routes to PCDD/ est resulted in commercial operations and pilot plant tests by, among Fs are reviewed, and the influence of the amount of PVC on the others, Lakeshore Copper on leaching residues, Phelps Dodge on cop- formation of these isomers is discussed. per matte, United Verde on granulated slag, and the USBM on molten slag. In most case, these were directed at producing sponge iron suit- 9:45 AM able for cementation of copper from spent leach solutions. Cementa- Synergetic Effects During Phosphorous Production in Sub- tion of copper on iron from acid mine drainage solutions in the “Al- merged-Arc Furnaces: Markus A. Reuter1; Diekske van der Pas1; chemists’ Age” is likely what gave rise to mythical stories of a Rob de Ruiter2; 1Delft University of Technology, Faculty of Appl. 2 “Philosopher’s Stone”. While none of the above facilities continue in

Earth Sci., Mijnbiuwstraat 120, Delft, The Netherlands; Thermphos, AM MONDAY operation nor is cementation of great interest in current flowsheets, Postbus 65, Vlissingen, The Netherlands there does remain the need to treat acidic mine and tailing pond drain- In this paper, the kinetics of phosphorous production in submerged- age. In a related field, there has also been increasing interest within the arc furnaces will be discussed as a function of temperature, as well as steel industry to recover iron from various steel plant iron oxide various ore and reductant types. Interesting positive synergetic effects wastes to supplement a tightening supply of pig iron and scrap. Many on the rate of reaction could be observed when mixing different types steel waste plants propose to use technologies and processing concepts of ores. The results will be discussed with reference to a kinetic model, similar to those practiced earlier on the copper industry. This paper microprobe analyses, etc. The effects these results have on the con- will review the processes and designs used to make sponge iron from trol of the furnace will also be discussed in detail, indicating how these copper residues, identify the factors that led to success or failure in could be incorporated into the electrode and metallurgical control these approaches, and then apply those results to evaluate potential systems for submerged arc-furnaces. operating difficulties with the technologies being proposed and in- 10:10 AM Break stalled for steel plant wastes. While there has been no visible effort to cross-fertilize technologies between the ferrous and non-ferrous indus- 10:25 AM tries in this field, this paper will identify where such information Peirce-Smith Converter Hood Design Analysis Using Compu- transfer may be desirable. tational Fluid Dynamics Modeling: Paykan Safe1; 1Gas Cleaing Technologies Inc., 4950 North O’Connor Rd., Ste. 250, Irving, TX 11:45 AM 75062 USA The Case for the Copper Mini Smelter: Rolf J. Wesley1; 1Kvaerner Computational fluid dynamics (CFD) modeling provides a powerful Metals, 12657 Alcosta Blvd., San Ramon, CA 94583 USA tool to assist with the design of ventilation and fume control systems In recent years the trend in Copper smelting has been to expand in smelters and other high temperature metallurgical facilities. For this existing smelters to increase their throughput. New smelters that are paper, this tool has been used to analyze the off-gas flow patterns being considered are very large. Despite this trend to larger smelters, exiting the mouth of a Peirce-Smith converter into a water-cooled there are still a number of conditions where a small smelter can be hood and drop out box. The effects of various process and physical economically viable. The paper examines these conditions and out- plant design parameters on process gas and fume capture and potential lines the process concepts for a small smelter. The paper outlines build up on the converter hoods was examined, and the optimum design several options for treatment methods and presents a summary of the and operating parameters were determined. economic conditions that would lead to a successful small smelter project. 10:50 AM Process Control Improvements at the Kennecott Utah Copper Smelter: Robert M. Leary1; Marielle A.S. Siraa2; 1Kennecott Utah Copper Corporation, Smelter, P.O. Box 329, 12000 W. 2100 S., Ma- gna, UT 84044 USA; 2Rio Tinto plc, Tech. Svcs. Ltd., P.O. Box 50, High-Temperature Superconductors: Castlemead Lower Castle St., Bristol, England BS997YR UK BSCCO Tapes & Applications The Kennecott Utah Copper Smelter operates two Outokumpu flash furnaces: a smelting furnace for production of high-grade matte and a Sponsored by: Electronic, Magnetic & Photonic Materials converting furnace for production of blister copper. Flash furnaces Division, Structural Materials Division, Superconducting typically possess several characteristic features that must be consid- Materials Committee ered in process control development such as long lag times associated Program Organizers: U. Balu Balachandran, Argonne with settler volume, non-linear input and output responses, large pro- National Laboratory, Argonne, IL 60439 USA; Pradeep cess gains, and unmeasured disturbances. Additionally, the Kennecott smelter possesses certain unique characteristics which must be consid- Haldar, Intermagnetics General Corporation, Latham, NY ered such as a single mine concentrate source, small concentrate blend- 12110-0461 USA; Chandra Pande, Naval Research Labora- ing capacity, feed preparation facilities that introduce significant lags tory, Materials Science and Technology Division, between furnace control parameters and manipulated set points and Washington, DC 20375-5000 USA converter slag chemistry. In order to improve furnace control and on- line time, a process control system was developed which features feed forward and feed back control. The feed forward control module is Monday AM Room: Canal D based on a steady-state heat and mass balance that is executed in March 13, 2000 Location: Opryland Convention Center response to furnace feed changes. The feed back control module is based on Proportional-Integral control equations that were developed Session Chair: U. (Balu) Balachandran, Argonne National by statistical inference and are executed in response to furnace product Laboratory, Ceramics Section, Argonne, IL 60439 USA grade and temperature deviations from set point. To provide regular feed back information to the control room operators, new sampling methods were developed which allow the operators to obtain molten 8:30 AM Invited metal samples at hourly intervals and allow for rapid laboratory turn High-Tc Conductor Development for Use in Electric Power De- around. The control system was implemented in May 1999 and a vices: Heinz-Werner Neumueller1; 1Siemens AG, ZT EN4, P.O. Box 11 review of it’s operation, adjustments, and future work will be discussed. 3220, Erlangen D-91050 Germany Demonstration of HTS technology in power systems requires devel- 10:40 AM opment of practical and robust conductors on technical scale. Mean- Histographic Analysis of the Microstructure of Ag/Bi-2223 Com- 1 1

MONDAY AM while several manufacturers offer elementary conductors like 2223 posite Conductors*: Roxanne Baurceanu ; Nazarali N. Merchant ; tapes having reasonable engineering current densities in quantities suf- Albert K. Fischer1; Victor A. Maroni1; Ronald D. Parrella2; 1Argonne ficient for the manufacturing of representative power devices like National Laboratory, Chem.Tech. Div., 9700 S. Cass Ave., Argonne, transformers and current limiters for use in first pilot systems. Similar IL 60439 USA; 2American Superconductor, Two Technology Dr., to the LTS conductor development the realization of larger high cur- Westborough, MA 01581 USA rent HTS power devices need advanced cabled conductors designed for A group of procedures has been developed to identify, quantify (in AC-application. Robel bars have been manufactured consisting up to terms of area fraction), and spatially map the nonsuperconducting 13 tapes of BPSCCO 2223 multifilamentary tapes. The production second phases (NSPs) that are formed during heat treatment of Ag/Bi- line delivers the conductor material for the low voltage winding of the 2223 multifilament composite conductors. These procedures involve 1 MVA railway model transformer currently being under construction (1) extracting the gray scale histogram from scanning electron micro- and avoids complicated and expensive coil winding. In course of the scope images of transverse cross sections of Ag/Bi-2223 after varying resistive fault current limiter development a continuous production of degrees of thermal treatment, (2) correlating selected ranges of gray switching elements has been established. Design considerations, qual- scale values with the energy dispersive x-ray scans of those regions (to ity measures and test results of the 1 MVA model will be presented. obtain metallic element ratios), (3) performing Raman microscopy analyses of the same regions (to identify the phases present), and (4) 9:10 AM Invited making systematic measurements of the Bi-2223 grain colony size and Fatigue Behavior of Multifilamentary BSCCO Wire Used in texture factor as they relate to NSP size, content, and composition. Superconducting Ac Motors for Navy Ship Propulsion: Donald From these results we have developed quantitative correlations be- U. Gubser1; 1Naval Research Laboratory, Matls. Sci. and Tech. Div., tween key heat treatment parameters (such as, temperature, oxygen Code 6300, 4555 Overlook Ave. S.W., Washington, DC 20375 USA partial pressure, and treatment time) and the chemical form of the A new type of ac superconducting motor is under development for NSPs, their size distributions, their area fractions, and their impact on the US Navy. This motor uses BSCCO conductor, wound into racetrack the final microstructure of the filaments. We find that oxygen partial magnets, mounted on the rotor. Such magnets will be subjected to pressures and temperatures on the high end of the Bi-2223 stability considerable cyclic stress, both during operation and during thermal range tend to encourage the formation of the 14/24 alkaline earth cycling. It is well known that a monotonic strain of more than a few cuprate, whereas oxygen partial pressures and temperatures on the low tenths of a percent can degrade the critical current in high temperature end of that range tend to encourage the 2/1 alkaline earth cuprate. The superconductor wires. A much lower strain, if applied repeatedly, also quality of the Bi-2223 grain colony microstructure is most sensitive to can degrade the critical current through cumulative damage effects. heat treatment temperature and the presence of large NSPs. The opti- The possible fatigue damage of HTS wires is a significant concern for mum temperature for achieving a robust grain colony microstructure the reliability and service life issues in the development of motors and tends to increase with increasing oxygen partial pressure. *Work spon- other power equipment. We report on measurements of the critical sored by the U.S. Department of Energy, Energy Efficiency and Re- current fatigue in commercial BSCCO/Ag multi-filamentary wires. Long newable Energy, as part of a DOE program to develop electric power (250 mm) length sections of the wire were measured in liquid nitrogen technology, under Contact W-31-109-ENG-38. using a conventional servo-hydraulic mechanical test system and with sinusoidal loading at a frequency of 10 Hz and zero load ratio. Strain 11:20 AM Invited ranges were from 0.01 to 1.0 percent. Critical current failure, using a Development of Bi-2212/Ag Conductors and Coils: Hiroaki stringent 0.1 microvolt-centimeter field criteria, was measured as a Kumakura1; Hitoshi Kitaguchi1; Hanping Miao1; Kazumasa Togano1; function of the number of load cycles at each strain level. The fatigue Tsutomu Koizumi2; Nozomi Ohtani2; Takayo Hasegawa2; Katsumi limit is determined from the strain-life curves. The relationship of the Ohata3; Junichi Sato3; Kazuhide Tanaka4; Michiya Okada4; 1National fatigue limit to the monotonic critical strain is discussed. In addition, Research Institute for Metals, 1-2-1 Sengen, Tsukuba, Ibaraki 305- systems advantages of superconducting motors for Navy ships will be 0047 Japan; 2Showa Electric Wire & Cable, 2-1-1 Odasakae, Kawasaki, discussed. Work is supported by the Office of Naval Research. Kanagawa 210-8660 Japan; 3Hitachi Cable Limited, 3550 Kidamari, Tsuchiura, Ibaraki 300-0026 Japan; 4Hitachi Limited, 7-1-1 Ohmika, 9:50 AM Break Hitachi, Ibaraki 319-1292 Japan 10:00 AM Development of two types of Bi-2212/Ag superconductors with Grain Morphology of High Tc Superconducting Wires for Su- excellent current carrying capacities is now in progress. One is a sur- perconducting Motors: C. S. Pande1; K. L. Zeisler-Mashl1; R. A. face-coated multilayer tape conductor prepared by applying Pre-An- Masumura1; 1Naval Research Laboratory, Matls. Sci. Div., Washing- nealing and Intermediate Rolling (PAIR process) before a heat treat- ton, DC 20375 USA ment. The other is Bi-2212 multifilamentary wires fabricated by ap- Superconducting properties of practical high Tc superconductors plying Rotation Symmetric Arranged Tape-in-tube (ROSAT process, are strongly influenced by their grain morphology. Towards this goal, where Bi-2212 tapes were arranged with triple rotation symmetry. We texture measurements were conducted for BSCCO 2212 (Bismuth- evaluated current carrying characteristics of these Bi-2212 conductors Strontium-Calcium-Copper Oxide) tapes made by dip coating or by at various temperatures and fields. Excellent Ic and Jc values of about powder-in-tube techniques. BSCCO 2212 grain texture measurement 380A and 2?~105A/cm2 were obtained in a field of 30T at 4.2K for was performed for both c-axis using (001) pole figures from (008) short tapes cut from the PAIR processed 100m tape. E(electric field)- reflections and a-b axes using (115) pole figures. Current transport J(current density) characteristics was also improved by the PAIR pro- properties of these tapes were also measured and correlated with tex- cess. Jc values of pancake coils prepared with 100m-class PAIR pro- ture parameters obtained from contours of the texture plots. Grain cessed tapes were much higher than those of the no-PAIR processed morphology was inferred from the texture plots and was found to be tape. The ROSAT wires show very small Jc anisotropy with respect to consistent with a model based on global alignment of the c-axis and the the field orientation in spite of excellent Jc values. A 990-filament presence of colonies of grains differing mostly in c-axis twist. There is wire showed Ic and Jc of 360A and 105A/cm2 in 28T at 4.2K. Re- a good correlation between the c-axis texture and Jc. Surprisingly on a cently, we fabricated 400m-length ROSAT wires, and constructed a global basis the system showed little a-b texture. However the material solenoid magnet using these wires. Test result of the magnet will be did give indications of local a-b texture in addition to the c-axis tex- reported. ture. These results far as the grain morphology is concerned can be explained in terms of colonies of grains. Inside a typical colony, the grains differ mostly in their small amount of twist along c-axis. These colonies are connected by complicated grain boundary structures.

12 9:20 AM Influence of Trace Impurities on the High-Temperature Me- International Symposium on Iridium: chanical Properties of Iridium: B. Fischer1; Andreas Behrends1; D. Lupton2; J. Merker2; 1Fachhochschule Jena, Univ. of Appl. Sci., Mechanical Properties Tatzendpromenade 1b, Jena 07745 Germany; 2W. C. Heraeus GmbH & Sponsored by: Structural Materials Division, Refractory Company KG, Matls. Tech. Div., Heraeusstrasse 12-14, Hanau 63450 Metals Committee Germany Program Organizers: Evan K. Ohriner, Oak Ridge National Iridium is used as a high temperature material at temperatures up to 2000°C, for example, for high-strength components in space technol- Laboratory, Oak Ridge, TN 37831-6083 USA; H. Harada, ogy. Trace impurities can favour the formation of intercrystalline National Research Institute for Metals, Tsukuba, Ibaraki 305 cracks (processing problems) and reduce the necessary strength and Japan; R. D. Lanam, Engelhard-CLAL, Careret, NJ 07008 ductility of iridium for this extreme field of application. Because no USA; Peter Panfilov, Ural State University, Ekatrinburg detailed data on the influence of trace impurities have been published, 62001 Russia examinations were first carried out on the doping effect of the elements iron and silicon on high-purity iridium in different concentrations (27-1300 ppm). By means of a suitable production process, it is AM MONDAY Monday AM Room: Jackson A/B possible to avoid grain boundary segregations of trace elements which March 13, 2000 Location: Opryland Convention Center are difficult to remove under industrial conditions. The metal is now easier to process, the tendency to intercrystalline cracking is reduced Session Chairs: Evan K. Ohriner, Oak Ridge National and a larger amount of trace impurities is tolerable than was previously assumed. Only a small effect of the added elements on the stress- Laboratory, Metals and Ceramics Division, Oak Ridge, TN rupture strength of iridium at 2200°C in the short time range (<10 37831-6083 USA; William J. Barnett, U.S. Department of hours) could be observed. However, distinct differences in the creep Energy, Office of Space and Defense Power Systems, behaviour of the doped heats were found relative to pure iridium. Germantown, MD 20874-1290 USA 9:40 AM Brittle Transcrystalline Fracture in Plastic Face Centered Cubic 8:30 AM Invited Metal Iridium: P. Panfilov1; 1Urals State University, Lab. of Strength, Micro- and Macro-Alloying of Ir-Base Alloys: E. P. George1; C. T. Ekaterinburg 62001 Russia Liu1; 1Oak Ridge National Laboratory, Mets. and Cer. Div., P.O. Box The main puzzle of iridium is an inclination to cleavage after severe 2008, Oak Ridge, TN 37830-6115 USA plastic deformation. Evolution of transcrystalline cracks in bulk crys- Ir-base alloys are of interest for structural applications at high tals and thin foils of iridium is the subject for discussion in this paper. temperatures because of their high melting point (2443°C) and good Tested crystals did not content dangerous non-metallic impurities and oxidation and corrosion resistance. A major concern for structural use level of metallic contaminants was minimal what allows considering is their low tensile ductilities when tested at conventional strain rates brittleness as inherent property of iridium. Bulk crystals failed after at ambient temperatures and at high strain rates at elevated tempera- considerable elongation, however, necking did not appear in them. It tures. Microalloying has been used to strengthen grain boundaries and was shown that octahedral slip gives the main contribution to plastic suppress brittle intergranular fracture in Ir alloys. Auger studies indi- deformation, therefore, mechanical twinning or non-octahedral slip cate that Th has a strong tendency to segregate to Ir grain boundaries could not be a cause for cleavage. Sharp cracks appeared in strength- and suppress intergranular fracture at elevated temperatures. Among ened material near power concentrators of stresses. Sometimes, plas- macroalloying elements, Hf is found to be the most effective in im- tic deformation accompanied crack growth, but this did not lead to proving the strength of Ir alloys at room and elevated temperatures. crack tip blunting. Motion of cracks on primary ({100}) and second- Ir-W alloys doped with Th have been successfully developed as clad- ary ({210}) cleavage planes were observed. Evolution of cracks in thin ding materials for space power applications at temperatures to 1400°C. foils was considered in detail. It is unbelievable, but cracking of iridium The current studies of Ir-base γ-γ alloys and intermetallic alloys will be foils looks like fracture of ductile metal: microcracks emit both twins also briefly reviewed. and perfect dislocation, dislocation emission causes crack tip blunting, and dangerous cracks possess zigzag profiles. In contrast with usual 9:00 AM f.c.c.-metal, iridium foils contain high dense <110> dislocation nets, Comparing Experimental Measurements with Ab Initio Simu- which bother emitted dislocation to move from crack tip, and, as a lations of the Elastic and Plastic Behavior of Single Crystal- result, crack leaves ability to emit dislocations. After that crack should line Iridium: T. J. Balk1; O. N. Mryasov2; Y. N. Gornostyrev3; P. either stop or continue its growth without dislocation emission like Panfilov4; A. J. Freeman2; K. J. Hemker1; 1Johns Hopkins University, crack in brittle crystal. Microcrack will have an opportunity to trans- Dept. of Mech. Eng., 200 Latrobe Hall, 3400 N. Charles St., Balti- form in zigzag crack if dislocation nets are absent around it. Observa- more, MD 21218 USA; 2Northwestern University, Dept. of Physics tions of cracks have shown that brittle transcrystalline fracture is and Astronomy, Rm. F275, 2145 No. Sheridan Rd., Evanston, IL property of bulk iridium crystals only. TEM study allows revealing 60208-3112 USA; 3Instit. of Metal Physics, 18 S. Kovalevskaya St., microscopic cause of brittleness in iridium, while its thin foils failed by Ekaterinburg 620219 Russia; 4Urals State University, Instit. of Physics ductile manner. This is its ability to store high dense dislocation nets. and Appl. Math., Ekaterinburg 620083 Russia During preliminary deformation, plastic iridium crystal exhausts the Iridium is one of two face-centered cubic (FCC) metals that is known resource of plasticity (nets cover all volume of crystal) and further to undergo brittle fracture, in stark contrast with the normal ductile loading should induce brittle fracture of sample. failure of other FCC metals. The occurrence of brittle fracture, which follows significant plastic deformation of up to 70%, is thought to 10:00 AM Break result from the energetics of the dislocation core. Ab initio first- 10:10 AM principles methods have been used to predict fundamental characteris- Strength Behavior of Ir-Based Refractory Superalloys: Y. tics that govern the mechanical behavior of iridium, e.g., elastic con- Yamabe-Mitarai1; Y. Gu 1; Y. Ro1; S. Nakazawa1; T. Maruko2; H. Harada1; stants, dislocation structure and fracture parameters such as surface 1National Institute for Metals, HTM21Project, 1-2-1 Sengen, Tsukuba, and unstable stacking energies. The elastic behavior and strength of Ibaraki 305-0047 Japan; 2Furuya Metal Company Limited, No.1915, single crystalline iridium have been measured experimentally. These Morizoeshima, Shimodate, Ibaraki 308-0861 Japan measurements and transmission electron microscopy (TEM) observa- We have proposed “refractory superalloys” using platinum group tions of the dislocation core structure will be compared with the first- metals, especially Ir, as ultra-high temperature materials. The refrac- principles predictions, in order to better understand the fundamental tory superalloys are defined as the alloys with an fcc and L12 two- mechanical behavior of iridium. phase coherent structure and with yet higher melting temperature than 13 Ni-based superalloys that are used as high temperature materials like nary Ir-Nb-Ni-Al alloys have never been studied. Therefore, in the turbine blade. High strength of Ni-based superalloys at high tempera- present paper, microstructure evolution, element distribution and lat- ture is attributed to the fcc and L12 two-phase coherent structure. tice misfit of two kinds of fcc/L12 as well as 0.2% flow stress at room MONDAY AM Compression strength, creep properties, and microstructure up to temperature and 1200°C in quaternary Ir-Nb-Ni-Al will be investi- ° 1800 C were investigated in the Ir-V, Ir-Ti, Ir-Nb, Ir-Ta, Ir-Hf, and Ir- gated. Zr binary systems. The fcc and L12 two-phase coherent structure formed in these alloys after heat treatment. The strengths of the two- 11:10 AM phase alloys are higher than those of fcc or L12 single-phase alloys. The Effects of Nb Content and Third Element Additions on the This shows that the main factor contributing to strengthening is pre- Fracture Behaviours of Polycrystalline Ir-Nb Two-Phase Al- cipitation hardening. Precipitate shape depends on lattice misfit be- loys: Y. Gu 1; Y. Yamabe-Mitarai1; H. Harada1; 1National Research tween the matrix and the precipitates. Plate-like and cuboidal precipi- Institute for Metals, HTM 21 Project, 1-2-1 Sengen, Tsukuba, Ibarake tates formed in the alloys with large (2%) and small (0.3%) lattice 305-0047 Japan misfit, respectively. Precipitation hardening is more effective for plate- Iridium (Ir) and its single-phase alloys have been tried as structural like precipitates because shearing or bypass of dislocation is difficult materials for ultra-high temperature applications, such as solar thrust- for plate-like precipitates and coherency strain at the interface be- ers in lightweight solar concentrators for use in space and as postimpact tween matrix and precipitates is high by large lattice misfit. Deforma- containment claddings for radioactive fuel. Ir and its alloys were cho- tion mechanism is discussed by observation of dislocation structures of sen for these applications because of their high melting point, excel- deformed samples. lent oxidation resistance, and welding suitability. However, polycrystalline Ir and its alloys normally exhibit grain-boundary (GB) fracture 10:30 AM with limited ductility in tensile tests at temperatures below 800°C. Effect of Ir Addition on High-Temperature Strength of NiAl Moreover, alloys with single-phase normally show less resistant to Single Crystals: A. Chiba1; T. Ono1; X. G. Li1; S. Hanada2; T. Sugawara2; creep deformation, a property that is important for structure materi- 1Iwate University, Dept. of Matls. Sci. and Tech., Morioka 020-8551 als at high temperatures. Recently, we developed a new class of two- Japan; 2Tohoku University, Instit. for Matls. Rsch., Sendai 980-77 phase superalloys, namely, refractory superalloy, based on platinum Japan group metals (PGMs). These refractory superalloys have a coherent In order to obtain the knowledge on mechanisms of enhancement fcc-L12 structure, similar to γ/γ’ microstructure in nickel-base superal- of high-temperature strength of NiAl by Ir addition, compression and loys, and have good potentiality as structural materials used at ultra- creep tests of soft [-223] oriented single crystalline NiAl and Ir-doped high temperatures up to 2000°C. Preliminary results showed that, of NiAl (Ni0.9Ir0.01Al) have been conducted in the temperature range these refractory superalloys, Ir-based fcc-L12 two-phase alloys, such from room temperature to 1473 K. CRSSs of Ni0.9Ir0.1Al single as Ir-15 at % Nb, Ir-15 at % Hf, and Ir-15 at % Zr alloys, were superior crystal are about a factor of 3, 4, and 6 higher than those of binary in high temperature strength and oxidation resistance. Despite the NiAl single crystal at room temperature, 1073 K and 1473 K, respec- importance of the relationship between the microstructures and defor- tively. The Ni0.9Ir0.1Al single crystal deforms by kinking instead of mation behaviours of these refractory superalloys for practical appli- slip of b=(-110)[001] dislocation which normally glide in binary NiAl cations, the fracture behaviour was also needed to be understood. The single crystal with soft [-223] crystal axis. Secondary creep rate of aims of the present study are: (i) to examine the effects of various Ni0.9Ir0.1Al single crystal is about a magnitude of 4 lower than that of niobium (Nb) contents on the microstructures and fracture behaviours binary NiAl single crystal at 1273 K; stress exponent of secondary of Ir-Nb two-phase refractory superalloys, (ii) to identify third ele- creep for Ni0.9Ir0.1Al and NiAl is approximately 3.0 and 4.8, respec- ment (Ni, Mo, C, and B) addition on the microstructures and fracture tively. Dislocation substructures of crept Ni0.9Ir0.1Al single crystal behaviours of Ir-15 at % Nb alloy, and (iii) to determine the relation- consist of subboundaries and gliding dislocations, indicating that dislo- ship between the microstructure and fracture behaviour of the alloy. cations of Ni0.9Ir0.1Al single crystal are more difficult to move than Our results showed that the intergranular fracture occurred in Ir single- those of binary NiAl single crystal. It is likely that addition of Ir to phase alloys could be governed by controlling the microstructures NiAl enhances the Peierls stress of (-110)[001] slip system of NiAl around grain-boundary (GB) and alloyed with some third elements. and leads to the activation of non-b=(-110)[001] dislocation and (or) kinking. 11:30 AM Mechanical Behavior of Ir-Sn Layered Crystals: P. Panfilov1; Y. 10:50 AM L. Gagarin1; A. V. Yermakov2; 1Urals State University, Lab. of Strength, Microstructure and Mechanical Properties of Quaternary Ir- Ekaterinburg 62001 Russia; 2Ekaterinburg Non-Ferrous Metals Pro- Nb-Ni-Al Alloys: X. Yu1; Y. Yamabe-Mitarai1; T. Yokokawa1; M. cessing Plant, The Head of Rsch. Ctr., Lenin Ave. 8, Ekaterinburg Osawa1; Y. Ro1; H. Harada1; 1National Research Institute for Metals, 620014 Russia High Temp. Matls. 21 Project, 1-2-1 Sengen, Tsukuba, Ibaraki 305- Iridium based compounds are prospective materials for exploitation 0047 Japan in aggressive environments, but poor plasticity and brittleness make Many attempts have been made in order to improve the tempera- considerable doubts for their industrial applications. Elaboration of ture capability of Ni-based superalloys by adding more refractory ele- layered iridium compounds would help to solve the problem of techno- ments into them, such as Re, W, Mo, Ta, et al. Single crystal Ni-based logical brittleness, in as much as layered structure of sample could superalloys are classified by the level of Re content. But the biggest suppress crack growth and provide plastic deformation even in brittle problem is phase stability. Since Re has a low diffusivity and tends to be crystals. Single crystals of Ir-Sn compound were grown by means of segregated in matrix, the addition of Re assists in the formation of a high temperature synthesis in vacuum. Silver lustrous and metallic topologically close-packed (TCP) phase. Another question is the melt- electric conductivity was inherent to crystals. Chemical analysis has ° ing temperature of Ni (1450 C). It can not be used at higher tempera- shown that material contains Ir and Sn in proportion of 1:1. Samples ture. Developing new alloys whose matrix elements are of higher possessed tetragonal lattice with ratio of c/a<<1 and their morphology melting temperature is another way. Ir attracts researcher’s attention was similar to “sandwich” formed from one hundred thin square plates ° due to the higher melting temperature (2240 C) and superior oxida- (thickness of each plate is 10-3mm). These features did not allow to tion and the fcc/L12 coherent structure in Ir-based alloys. The fcc/ built simple crystallographic model for the compound. Samples were L12 coherent structure provides a challenge for combining Ir- and Ni- indented by Vickers diamond pyramid at room temperature. Deep based alloys to prepare new alloys. Therefore, we do the efforts to holes remained on the surface after indentation, but this did not lead to investigate quaternary Ir-Nb-Ni-Al in the last two years. The previous the separation of crystal. Sliding of plates or single crystal layers is the results indicated the two kinds of fcc/L12 (fcc/Ir3Nb and fcc/Ni3Al) main mechanism, which provides severe plastic deformation in vicin- coherent structure formed in some alloys and strength also increased ity of indents. Twin lamellas in <110> direction and cracks along drastically compared to Ni-based superalloys. These alloys are promis- <100> and <110> were observed in deformed single crystal layer. Cracks ing to be used at higher temperature. However, the microstructure have only appeared near indents, while twins were detected on the evolution of quaternary Ir-Nb-Ni-Al alloys is not clear, element distri- whole crystal. It was revealed that cracks in the first layer could not bution and lattice misfit of two kinds of fcc/L12 in the same quater- pass in depth of crystal. 14 catalyzed the Conformal Ionic Solution Theory, the only theory fun- damentally valid for molten salts. This theory later led to methods for Kleppa Symposium on High Tempera- accurately predicting the solution properties of multicomponent molten salt systems from data on the subsidiary binaries and the pure ture Thermochemistry of Materials: component salts. His measurements of binary systems with the two Session I components having the same cation and two different anions indicated that deviations from ideality were generally very small. A theoretical Sponsored by: ASM International: Materials Science extension of this conclusion to silicates and other polymeric slags led Critical Technology Sector, Extraction & Processing to reliable predictions of the solubilities (and sulfide capacities) of Division, Thermodynamics & Phase Equilibria Committee, ionic compounds. Kleppa’s work has had a major influence on molten Process Fundamentals Committee salt and slag chemistry. Program Organizers: Ray Y. Lin, University of Cincinnati, 9:45 AM Department of Materials Science and Engineering, Cincin- Thermochemical Studies of Oxynitrides by Oxidative High nati, OH 45221-0012 USA; Y. Austin Chang, University of Temperature Solution Calorimetry: Alexandra Navrotsky1; 1Uni- versity of California, Dept. of Chem. Eng. and Matls. Sci., Thermochem. MONDAY AM MONDAY Wisconsin, Department of Materials Science & Engineering, Facility, Davis, CA 95616 USA Madison, WI 53706-1595 USA; Dr. Susan Meschel, The Thermodynamic properties of nitrides and oxynitrides are poorly University of Chicago, Chicago, IL 60637 USA; Ramana known, despite technological importance and scientific interest. Re- Reddy, University of Alabama, Department of Metals and cent advances in oxidative drop solution calorimetry of nitrogen- Materials Engineering, Tuscaloosa, AL 35487 USA containing materials in molten oxide solvents at 973-1073 K enable the determination of enthalpies of formation. The calorimetric methodology is described and applied to three groups of materials: the beta Monday AM Room: Lincoln E sialons in the Si-Al-O-N system, cubic oxynitrides in the Zr-O-N and March 13, 2000 Location: Opryland Convention Center Zr-M-O-N(M = Y, Ca, Mg) systems, and phosphorus oxynitrides in the P-O-N and Li-P-O-N systems. The energetics of oxygen-nitrogen Session Chairs: Susan V. Meschel, University of Chicago, substitution these systems is discussed in terms of crystal chemistry, bond strengths, and short range order. Chicago, IL 60637 USA; J. C. Gachon, Universite Henri Poincare, Lab de Chimie du Solide Mineral, Vandoeuvre, 10:15 AM Break Cedex 54506 France 10:30 AM What Will Be Done in the Future with the Enthalpy Data Set of O. J. Kleppa: Jean Hertz1; 1Universite Henri Poincare-Nancy I, 8:30 AM Lab. de Thermodyn. Metallu., Umr Cnrs 7555, Chimie du Solide Min- Some Like it Hot: Evolution and Applications of High-Tem- eral BP 239, Vandoeuvre, les Nancy-Cedex 54506 France perature Reaction Calorimetry at University of Chicago from After 40 years or more of experimental work devoted to thermo- 1 1 1952 to 2000: Ole J. Kleppa ; University of Chicago, James Franck chemistry of metallic alloys it will be time to wonder: what will be done Instit., Chicago, IL 60637 USA in the future, by the scientific community, with the patrimony of data The author will present a review of his work in the field of high- I have obtained? This question is of particular importance for O. J. temperature reaction calorimetry. This review will be partly histori- Kleppa with his fantastic panel of consistent enthalpy data, obtained cal, partly scientific. He will touch on his work on low-melting liquid by his group for more than 45 years of unbroken calorimetry experi- alloys, on the thermochemistry of some Hume-Rothery type binary ments relative to more than 200 different binary systems. The progress alloys, on the heats of mixing of molten salts, on the development of of phase diagram calculation of multicomponent systems, is signifi- oxide melt solution calorimetry, on the thermodynamics and thermo- cant as far as industrial applications for new alloys development and chemistry of metal-hydrogen systems, and on the development and metallurgical processes are now in due course. That will be the main construction of a number of different reaction calorimeters suitable topic of the near future metallic thermodynamics. That means that ° for work at temperatures up to about 1200 C. Finally he will give an very simple models are generalised: the Redlich-Kister multicompo- introduction to his more recent investigations of refractory interme- nent model, coming from the petroleum industry, and the Hillert sub- tallic and related compounds. This section will include an outline of lattice model for intermediate phases provide a very large domain of the special technique of solute-solvent drop calorimetry, a technique applications, useful for the main multicomponent metallic systems. which is particularly suitable for very refractory compounds. How- Unfortunately such works cannot start out of nothing, but out of ever, most recently his studies of refractory compounds have empha- consistent thermodynamic data used to fit the binary systems first, sized the thermochemistry of congruent melting compounds with then the ternaries. Higher order terms are generally not needed. The melting points below about 2000°C using direct synthesis calorimetry enthalpy of mixing of the liquid phase in the whole range of composi- ° at 1200 C. More detailed discussions of these investigations will be tion and the enthalpy of formation of compounds are of significant presented in the invited papers given by his co-workers S. V. Meschel interest to obtain a set of coherent multicomponent data bank. In the and Qiti Guo. 80ies we have trusted the progress of band theory and physical quantum 9:15 AM mechanics to provide a lot of “ab initio” or semi-fitted energetic data Contributions to Molten Salt Chemistry by Ole J. Kleppa: set. Unfortunately the relative phase stability in a multicomponent Milton Blander1; 1Quest Research, 1004 E. 167th pl., South Holland, system depends on only some hundredth of eV and the precision of the IL 60473-3114 USA calculated cohesive energy will not attain 0.1 eV in the more accurate Ole Kleppa and associates have accurately measured the enthalpies results. The interest of this part of the physical thermochemistry of mixing of a large number of binary molten salt systems. These remains for understanding the metallic bonding, but not for practical results have also been proven to be useful in the analyses of phase applications. In my opinion and for a very long period the only source diagrams and in creating a reliable database on free energies of mixing of information for realistic metallic multicomponent phase diagram of a large number of systems. He made a general confirmation of a previsions will be the good experimental binary and ternary data: specific result by Hildbrand and Salstrom that excess free energies of enthalpy and chemical potential measurements, each one needed to mixing of simple binary molten salts could be represented by a simple calibrate the two enthalpy and entropy contributions of the Gibbs- polynomial, an important result for ionic systems with very long function. Experimental equilibrium lines and tie-lines in phase dia- range ionic pair interactions. His measurements of the enthalpies of grams could be considered as equivalent to a Gibbs-function informa- mixing of all binary alkali nitrates led to an expression which was close tion, when calorimetric data are available. For this reason the large to that deduced form a simple model by Forland. This result also Kleppa enthalpy data set patrimony will be of crucial interest for a 15 very long future period. We will illustrate this prognosis with various 8:10 AM multicomponent diagram previsions in the field of low melting metals. An Overview of the Aluminum Industry: Richard B. Evans1; 1 MONDAY AM 11:00 AM President, Alcan Global Fabricatin Group, 6060 Parkland Blvd., Cleve- Excess Thermodynamic Functions of Systems with N (N>6) Com- land, OH USA ponents: Measurements and Calculations: M. Gambino1; J. P. An overview and outlook of the global aluminum industry will be Bros1; Z. Moser2; M. Hoch3; 1Universite de Provence, Iusti, Ura-Cnrs presented. A focused look on aluminum’s two largest markets, packag- 6995, Rue Enrico Fermi 5, Marseille, Cedex 13 13453 France; 2Instytut ing and transportation, will be given. Podstaw Metallurgii im., Alexandra Krupkowskiego Pan, Krakow, ul 8:40 AM Reymonta 25 30-059 Poland; 3University of Cincinnati, Dept. of Materials Used in Aluminium Smelting: Harald A. Oye1; 1Nor- Matls. Sci. and Eng., Cincinnati, OH 45221-0012 USA wegian University of Science and Technology, Instit. of Chem., We measure the enthalpy of mixing along a line connecting the Trondheim N-7491 Norway center of the system with one component, and the partial enthalpy at The production of alumina, anode and cathode carbon will be re- the center of the system for all components. The calorimeter is a high viewed from a historic and the present point of view. Problems, chal- temperature Calvet type calorimeter, operating between 700 and 1000 lenges and new future advances will be discussed. K. For the calculations we use the Hoch-Arpshofen model, which uses only binary interactions. The agreement between calculated and mea- 9:10 AM 1 sured data is better than ±5%. Thus only a relatively few measure- Advancing the Hall Heroult Electrolytic Process: Barry Welch ; 1 ments are needed to understand the complete system. We discuss here The University of Auckland, Dept. of Chem. and Matls. Eng., Private the 7 component system (Bi-Cd-Ga-In-Pb-Sn-Zn). Measurements and Bag, Auckland 92019 New Zealand calculations of Zn activity in the system (Bi-Cd-Pb-Sn-Zn) show simi- The design and operating advances achieved in the last quarter lar excellent agreements. century will ensure the Hall Heroult technology will maintain a competitive advantage over alternative aluminium production processes 11:30 AM for some time into the future. The advances were lead by magnetic Thermochemistry of Alloys of Transition Metals and Lanthanide compensation and computerised process control coupled with electro- Metals with Some IIIB and IVB Elements in the Periodic Table- lyte optimization. These enable larger more economic cells to be An Overview: S. V. Meschel1; O. J. Kleppa1; 1The University of designed. During the same time the fundamental studies have enabled a Chicago, James Franck Instit., 5640 S. Ellis Ave., Chicago, IL 60637 better understanding of the subtleties of the processes and secondary USA reactions that were ignored in the theoretical understanding whilst the We have in this laboratory conducted systematic studies of the cells performed poorly. These secondary processes, including reac- thermochemistry of transition metal and rare earth alloys by high tions associated with impurities and anodes consumption, those lead- temperature calorimetric methods. An overview of the thermochem- ing to onset of anode effect, and alumina dissolution kinetic have not istry of the alloys of the transition metals and lanthanide metals with been fully exploited yet. Today as the focus shifts to higher productiv- elements in the IIIB and IVB columns of the periodic table will be ity, the dynamics of the cell and the impact operations have on the presented. The enthalpies of formation of most of these compounds very finely tuned heat balance becomes more important. With the were determined by high temperature direct synthesis calorimetry. high current efficiencies and low margins for error in modern cells the This review will summarize the trends between the enthalpies of for- present challenge is to refine designs, control strategy and operating mation of the TR-X and LA-X alloys (where X is a IIIB or IVB practices so that further marginal gains and economic performance element) and the atomic numbers in each transition metal and lan- can be achieved. This will include better management of aluminium thanide metal family. We will compare our measured enthalpies of fluoride, prevention of anode effects, and earlier detection of the formation of each alloy family for the 3d, 4d and 5d transition metal increasingly prevalent anode spikes. Super structure design changes elements. We will also compare our experimental measurements with coupled with improved control and practice will also enhance produc- predicted values on the basis of Miedema’s semi-empirical model. This tivity of future generations of cells. review will show examples of a correlation between the enthalpies of formation of the alloys of the lanthanide elements with the non-metal 9:40 AM Break elements in the IIIB and IVB columns in the periodic table. We will 10:00 AM also show some comparisons of our measured enthalpies of formation A Perspective on Aluminum Melting and Metal Treatment: C. with the predictions by Gschneidner for the lanthanide alloys. Edward Eckert1; 1Apogee Technology Inc., 1600 Hulton Rd., P.O. Box 12:00 PM 101, Verona, PA 15147-2314 USA Abstract Text Is Unavailable: F. Sommer Essentially all commercially significant aluminum produced shares a common processing history; melting and metal treatment. These two operations therefore have a monumental impact on production costs, the ultimate quality of end-use products, and also have an ancillary influence on environmental issues. Melting and metal treatment Light Metals Division Plenary Session: processes understandably remain developmentally topical. The tech- Aluminum Plenary nological heritage of aluminum melting and metal treatment will be Sponsored by: Light Metals Division, Aluminum Committee chronicled, and, importantly, significant technical milestones identified. These milestones are associated with specific product/commer- Program Organizer: Ray D. Peterson, IMCO Recycling cial imperatives or a revolutionary development. An example of the Inc., Rockwood, TN 37854 USA former is the emergence of the aluminum beverage container in the 1960 timeframe, while the latter is exemplified by rotary impeller in- Monday AM Room: Presidential Ballroom line treatment. Finally, an inventory will be provided of contempo- March 13, 2000 Location: Opryland Convention Center rary aluminum melting and metal treatment technology, critical needs assessed, and a projection offered of future development. Session Chair: Ray D. Peterson, IMCO Recycling Inc., 10:30 AM Rockwood, TN 37854 USA Aluminum Solidification Processing-Prospective and Retro- spective Views of the Industry and the Field: Diran Apelian1; 1Worcester Polytechnic Institute, Aluminum Cast. Rsch. Lab., Met. 8:00 AM Introductory Remarks Proc. Instit., Worcester, MA 01609 USA Dr. Ray Peterson, IMCO Recycling Inc., Rockwood, TN 37854 USA During the last 50 years, aluminum has evolved into one of the most important societal materials; it is used in a variety of diverse

16 applications-construction, automotive, aerospace, packaging, furni- makes the economics of a new magnesium plant much less favorable. ture, jewelry and a vast number of products, which once were made One of the big problems is process technology. There are literally no from ferrous or other materials. Specifically, during the last decade, we processes commercially available that have demonstrated sufficient have seen significant increases in the use of cast aluminum net-shaped development to be able to produce magnesium metal economically. manufactured components. For example, in 1980 there were 800,000 The closest technology is the Alcan cell, but it requires a very dry and tons of aluminum casting shipments in North America versus 1,800,000 pure anhydrous magnesium chloride feed. This is the basic area where tons in 1998. In this plenary lecture, a prospective review of the every project past, present and future has had problems. These prob- science and technology of aluminum metalcasting will be presented, lems are still not solved in as this paper is being written. for both primary aluminum production as well as metalcasting. This 8:55 AM will be followed with a retrospective presentation of the emerging Magnesium Electrolysis-A Monopolar Viewpoint: Oddmund technologies and challenges we face. The plenary lecture will be a Wallevik2; Ketil Amundsen1; André Faucher3; Thorvald Mellerud4; 1Hy- holistic review of solidification processing of aluminum, addressing: dro Magnesium, Oslo N-0246 Norway; 2Norsk Hydro ASA, Rsch. Ctr., where we have been, where we are going, and what are the exciting Porsgrunn N-3901 Norway; 3Norsk Hydro Canada, Bécancour, Canada; frontiers facing the industry. 4Hydro Magnesium, Brussels, Belgium

11:00 AM Norsk Hydro has produced magnesium in Porsgrunn, Norway, since AM MONDAY Aluminum Fabrication and Applications: Elwin L. Rooy1; 1Elwin 1951. The technology including the electrolysis was “inherited” from L. Rooy and Associates, 461 Ravine Dr., Aurora, OH 44202 USA IG Farben. Hydro has since then continuously developed the magne- Modern manufacturing strategies combine solidification and sium electrolysis, first by improving the IG technology, and then by thermomechanical process technologies for optimum efficiency, prod- developing its own “diaphragmless electrolyser” (DLE), now being uct quality and reliability, and product performance. The present and used for a number of years in Norsk Hydro’s plants in Porsgrunn as well future importance of incorporating melt processing and solidification as in Bécancour, Québec. A presentation will be made of the Norsk considerations into the sequence of down-stream operations for satis- Hydro high-amperage monopolar electrolysis cell. Its performance fying product requirements and for developing new competitive mar- will be described, as a basis for the conclusion that this type of cell ket capabilities forms an essential basis for these strategies. The ma- presently is very competitive compared to bipolar cell technologies, jority of aluminum is consumed in fabricated forms ranging from rolled although it has a higher energy consumption. products to components formed by powder metallurgy. Remelted and 9:20 AM cast products represent a rapidly growing manufacturing sector. The Investigation on Electrocatalysis for Energy Saving in Magne- evolution of processes for aluminum’s multivaried commercial shapes sium Electrolysis: Zhong Xie1; Ye-Xiang Liu1; 1Central South Uni- and forms paralleled the industry’s success in determined applications versity of Technology, Dept. of Nonfer. Metallu., #2 Lushan Nan Rd., and market penetration. The history of the aluminum industry’s de- Changsha, Hunan 410083 PRC velopment of casting, forging, extrusion and rolled products and the In the present paper, we report some research results on significance of process and product developments to the dramatic electrocatalysis for chlorine evolution reaction (CER) in Mg elec- evolution of aluminum as the metal of the twentieth century is re- trolysis. Investigation has been carried out on various oxide electrodes viewed, and current and projected developments are outlined. in equimolar NaCl-KCl melts at 700°C. Oxide electrodes were prepared by thermal decomposition procedure on graphite substate. Steady state linear potential sweep and an improved current interruption technique were used to investigate the electrocatalytic activity of Magnesium Technology 2000: transition metal oxides, rare earth oxides and their mixed oxides. Electrolytic Technology Pr6O11, Tb4O7, Tm2O3, RE+Ru and CoxFeyOz (x=0.75,y=2.25,z=4) mixed oxides showed good active for CER, reducing anode overpotential Sponsored by: Light Metals Division, Reactive Metals up to 80-110 mv at a current density of 0.6A/cm.sq. compared with Committee, International Magnesium Association graphite electrode. 200-250kWh/T-Mg energy saving could be achieved Program Organizers: Howard I. Kaplan, Magnesium if above mentioned electrodes being employed in Mg electrolysis. Corporation of America, Salt Lake City, UT 84116 USA; Attempt was made to elucidate the electrocatalysis mechanism. John N. Hryn, Argonne National Laboratory, Argonne, IL 9:45 AM 60439-4815 USA; Byron B. Clow, International Magnesium Inert Anodes for Magnesium Electrolysis: Jerry F. Moore1; John Association, McLean, VA 22101 USA N. Hryn1; Michael J. Pellin1; W. F. Calaway1; Kevin Watson2; 1Argonne National Laboratory, Energy Sys. Div., 9700 S. Cass Ave., Argonne, IL 60439 USA; 2Noranda Inc., Noranda Tech. Ctr., 240 Boul. Hymus, Monday AM Room: Bayou C Pointe-Claire, Quebec H9R1G5 Canada March 13, 2000 Location: Opryland Convention Center Magnola Metallurgy Inc. (MMI) will commission a 63,000 tpa primary magnesium production plant in June 2000. The plant will pro- Session Chair: Ramaswami Neelameggham, Magnesium duce magnesium using electrolysis cells with industry standard carbon Corporation of America, Salt Lake City, UT 84116 USA anodes. Undesirable by-products of the electrolysis process with carbon anodes are chlorinated hydrocarbons (CHCs). These represent a significant environmental concern, which MMI are committed to re- 8:30 AM Invited, Keynote ducing and eventually eliminating. One possible means to prevent the Magnesium Industry Growth in the 1990 Period: Robert E. production of CHCs is to replace the carbon anodes with non-carbon Brown1; 1Magnesium Monthly Review, 226 Deer Trace Rd., Prattville, “inert” anodes. The development of a viable inert anode material has AL 36067-3806 USA been a goal for the magnesium industry for many years. To date, no The world magnesium industry has experienced a continuing growth acceptable material has been found. The major technical hurdle is to of 6 per cent or more per year for over 10 years. Major growth has develop a material with the ability to withstand chlorination by the been in the die casting sector which has grown as much as 14% per year evolving chorine gas on the anode surface whilst conducting electrical over the last 10 years. New magnesium projects are being announced current efficiently. Argonne National Laboratory (ANL) has identi- frequently. In many countries there are large magnesium projects be- fied certain metal alloys that are promising candidate materials for ing discussed, studied, designed and constructed. Unfortunately, there is inert anodes. These alloys form self-limiting surface oxide films that much more discussion than there is construction. A review of the total are thin enough to allow current to pass, yet thick enough to prevent magnesium supply situation shows a great paradox. The prices of chlorination of the underlying metal. ANL are investigating the use of magnesium will have to be lowered to successfully market all of the these alloys as inert anodes under the joint sponsorship of MMI and magnesium production tonnage that is being discussed. Lowered prices the U.S. DOE, Office of Science, Laboratory Technology Research 17 Program. This paper presents a review of previous inert anode re- involves the use of high alumina refractories. The sintered refractories search and an update of the ANL project. fail because of the penetration of the low viscosity salts into the open

MONDAY AM porosity. The high alumina fused cast refractories appear to be the best 10:10 AM Break solution in this application. Different types of high alumina fused cast 10:20 AM products have been prepared and tested in SEPR laboratory. The main The Magnola Demonstration Plant: A Valuable Investment in properties demanded by the application have been taken into account: Technology Development and Improvement: K. Watson1; P. Ficara2; low penetration by the molten salts (porosity, cracks, crystal size), M. Charron2; J. Peacey2; J. Primak2; 1Noranda Inc., Noranda Tech. chemical stability in contact with MgCl2, high electrical resistivity. Ctr., Pointe-Claire, Quebec Canada; 2Magnola Metallurgy Inc., Magnola Some general trends can be drawn regarding the application of fused Proj. Off., 620 Rene-Levesque W., 10th Fl., Montreal, Quebec H3B1N7 cast alumina products in magnesium chloride cells. Canada Noranda will become a major producer of magnesium following the commissioning of its 63,000 tpa Magnola plant in June 2000. The Magnola plant will utilise new process technology to extract magne- Opportunities for Materials & Engi- sium from serpentine mine tailings. The technology is unique and will enable Noranda to become the world’s premier primary magnesium neering Research Funding From Gov- producer. This paper presents an historical overview of the Magnola ernment & Industry: Session 1 project from the preliminary process development at Noranda Sponsored by: TMS, Public & Governmental Affairs Incorporated’s Technology Centre through to operation of the pilot demonstration plant in 1996 & 1997 and finally to design of the full Committee, Young Leaders Committee scale Magnola plant. In particular, this paper will present some of the Program Organizers: Canan U. Hardwicke, General Electric major conclusions and improvements derived from the demonstration Company, GECRD, Niskayuna, NY 12309 USA; Samuel A. plant stage and will evaluate their impact on the development of the Davis, TIMET, Henderson, NV 89009 USA overall Magnola Process. An update of the current status of the plant construction and pre-commissioning is also provided. Monday AM Room: Bayou A 10:45 AM March 13, 2000 Location: Opryland Convention Center Magnesium Electrolytic Production Process: G. Shekhovstov1; V. Shchegolev1; V. Devyatkin1; V. Tatakin1; I. Zabelin1; 1Titanium Insti- tute, 180 Prospect Lenina, Zaporozhue 330035 Ukraine Session Chairs: Canan U. Hardwicke, General Electric The Titanium Institute/VAMI proposes two variants of the magne- Company, GECRD, Niskayuna, NY 12309 USA; Samuel A. sium electrolytic production process. The first variant is based on a Davis, TIMET, Henderson, NV 89009 USA two-stage preparation process of magnesium raw material carnallite (KCl.MgCl2.6H2O) for electrolysis. In the first stage, carnallite is dehydrated in fluidized bed dryers with output of 400 t/day. Operation 8:30 AM and control of the drying process is highly automated. The second An Outline of the Federation of Materials Societies (FMS): stage of carnallite dehydration is carried out in electric chlorinators John N. Mundy1; 1Consultant, 10720 Game Preserve Rd., Gaithersburg, with output of 150-200 t/day. In the chlorinators, carnallite is melted MD 20879-3106 USA and chlorine treated. Molten carnallite flows to the electrolysis cells. FMS is an umbrella organization whose member societies and affili- The electrolysis cells are connected in a flow line that operates as one ates represent the professional societies, universities and National highly productive electrochemical unit. By electrolyte flow, magne- Research Council Organizations which are involved with materials sium moves through the electrolysis cells and is accumulated in a science, engineering, and technology. The purpose of FMS is to aid the separator cell where it is extracted and passed to the casting house for materials community in obtaining information from and exchanging casting magnesium and magnesium alloys into ingots. Electrolysis cells information with the policy community. An important FMS goal is to current is about 200-300 kA. Magnesium and magnesium alloys are help the materials community to arrive at consensus materials policy refined in continuous refining furnaces with the capacity of up to 100 and to assist it in informing policy makers of materials concerns. TMS t/day. The process is adopted by magnesium and titanium-magnesium is a contributing member of FMS and it is valuable for members of TMS plants of Russia, Kazakhstan, and Ukraine. The best modern projects to be aware of how FMS fulfills these tasks. are realized at the DSM magnesium plant in Israel. The second varia- 8:55 AM tion of magnesium electrolysis production process is based on carrying An Overview of R&D in the Federal Government with Empha- out high dehydration of carnallite in fluidized bed dryers by HCl injec- sis on DOE’s Materials Research Programs: Louis Ianniello1; tion into chambers together with combustion gases. HCl is gained from 1DOE (retired) fuel burning in chlorine gas in magnesium electrolysis cells. Solid highly Research funding by the Federal Government approximates $80 dehydrated carnallite is charged into cells connected into flow lines billion per year, covering basic, applied and technology development, having centralized magnesium collection. This process has passed pi- both defense and civilian areas. Materials research is conducted and lot-commercial tests and is ready for industrial realization. The above- supported to some extent by almost every agency of the government. mentioned carnallite processing variants can be used for different types The three largest Materials Research funding agencies for external of raw material: magnesite, chlorine-magnesium solutions, sea water, support are the Department of Defense (DOD), the National Science dolomite, and carnallite. Foundation (NSF), and the Department of Energy (DOE). The talk 11:10 AM will help the audience put the Materials Research portion of the Fed- Solid-Oxide Oxygen-Ion-Conducting Membrane (SOM) Tech- eral budget into perspective and then provide some detailed informa- nology for Direct Reduction of Magnesium from Its Oxide: D. tion on the DOE programs. DOE conducts research at its own labora- E. Woolley1; U. B. Pal2; G. B. Kenney3; 1Boston University, Boston, tories and also funds research proposals submitted in response to so- MA USA licitations as well as unsolicited proposals. The talk will include infor- Abstract Text Not Available mation on the various offices that fund materials research and on opportunities for doing research and interacting technically with dif- 11:35 AM ferent DOE programs. Comparison of Fused Cast Alumina Products for Magnesium Chloride Cells: Alexandre Mauries1; D. A. Whitworth1; 1SEPR, 9:20 AM R&D, B.P. #1, Le Pontet, Cedex 84131 France Materials Opportunities in Energy Efficiency: Toni Grobstein The molten salt electrolysis of magnesium chloride requires high Marechaux1; 1U.S. Department of Energy, EE-20, 1000 Independence quality refractories. The reduction of silicon dioxide by magnesium Ave. S.W., Washington, DC 20585-0121 USA 18 Energy its production, use, and conservation is a huge part of the activities more closely with immediate business opportunities. Within world economy, and materials enable much of the new technology academia, the pressure on the faculty remains the same, to educate as needed to improve energy production and to use it more efficiently. many graduate students as they can support. In light of the above, The Office of Energy Efficiency and Renewable Energy in the US more research in universities is being conducted collaboratively, and in Department of Energy provides a wide variety of options in funding partnership with industry and government laboratories. This provides for research and development, from small grants for the development great opportunity for new faculty to establish their own graduate train- of inventions to industry cost-shared demonstration projects, and many ing and research programs. However, a proper balance between col- types of research and development in between. Opportunities for ma- laborative and individual research must be maintained. terials funding in the areas of industrial, transportation, power, and 11:10 AM building technologies will be discussed. University/Industry Cooperative Applied Research Initiative: 9:45 AM How It Works: Manoranjan (Mano) Misra1; 1University of Nevada, Opportunities for Materials Technologies in the Advanced Tech- Metallu. and Matls. Eng., Mackay School of Mines, Reno, NV 89557 nology Program: Clare M. Allocca1; 1NIST, Adv. Tech. Pgm., 100 USA Bureau Dr. Stop 4730, Bldg. 101, Rm. A225, Gaithersburg, MD 20899- The thrust of this paper is to highlight the successful accomplish-

4730 USA ments of the Applied Research Initiative program at the University of AM MONDAY The NIST Advanced Technology Program (ATP) is a unique part- Nevada, Reno. The industry/university partnership has brought sev- nership between government and private industry to accelerate the eral industries to work with junior and senior faculty in many research development of high-risk technologies that promise significant com- projects in the Metallurgical Engineering program. In addition, the mercial payoffs and widespread benefits for the economy. The Mate- program helped in generating large scale funding from the federal rials Technology community has already taken advantage of several agencies. In this talk, several factors including how to develop such ATP opportunities, and as a result has moved ahead. Following an infrastructure will be discussed. overview, this presentation will describe past and potential accom- plishments/opportunities in the area of materials technologies, including engineered surfaces and innovative forming techniques. In the area of engineered surfaces, industry has identified high risk, critical techni- Packaging & Soldering Technologies cal investments to include: (1) simultaneously improving engineered surface process designs and reducing cost through reduced development for Electronic Interconnects: Soldering time and increased yield and consistency; and (2) developing extremely and Packaging Technologies reliable and predictable surfaces which are integral to the design and Sponsored by: Electronic, Magnetic & Photonic Materials operation of a component, as opposed to mere life enhancement. Tools (e.g., process diagnostics and life/performance prediction) and Division, Electronic Packaging and Interconnection corresponding validation strategies have been identified as key to over- Materials Committee coming these barriers. In the area of innovative forming techniques, Program Organizers: Hareesh Mavoori, Bell Laboratories, industry has identified, as appropriate for ATP, technical barriers to Murray Hill, NJ 07974 USA; Srini Chada, Motorola, Planta- implementation of rapid prototyping/solid freeform fabrication, the tion, FL 33322 USA; Gautam Ghosh, Northwestern Univer- aspects of metals (and metal matrix composites) forming which represent a major leap forward rather than an incremental step, and next sity, Department of Materials Science, Evanston, IL 60208- generation technologies for ceramics and ceramic matrix composites 3108 USA; Martin Weiser, AlliedSignal Electronic Materials, forming. Potential investment areas include predictive tools for pro- Plated and Discrete Products, Spokane, WA USA cess control and scale-up, intelligent tool design, and innovative approaches to design optimization and automation. Monday AM Room: Lincoln D 10:10 AM Break March 13, 2000 Location: Opryland Convention Center 10:20 AM Thoughts on Federal Research Funding in MSE with Specific Session Chairs: G. Ghosh, Northwestern University, Dept. Examples Related to the National Science Foundation: Bruce of Mats. Sci., Evanston, IL 60208-3108 USA; P. T. Vianco, 1 1 A. MacDonald ; National Science Foundation, Div. of Matls. Rsch., Sandia National Laboratories, Matls. Joing Dept., Albuquer- 4201 Wilson Blvd., Rm. 1065, Arlington, VA 22230 USA There are widespread opportunities for research support by the U.S. que, NM 87185-1411 NM USA Federal Government in materials science and engineering. This can be viewed as an advantage since an investigator is not tied to one particu- 8:30 AM Opening Remarks lar source for funding. The disadvantage is that there is no single key to gaining federal support since the various funding agencies may have 8:35 AM Invited different goals and funding criteria. Clearly the pursuers of funds should Solder Reaction on Electroless Ni(P) in Low Cost Flip Chip be aware of the objectives and proposal requirements of the agency Technology: K. N. Tu1; 1University of California, Dept. of Mat. Sci. from which they are requesting support. Gaining this knowledge is Eng., Los Angeles, CA 90095-1595 USA complicated by the fact that the funding environment is dynamic; The wetting reaction between eutectic SnPb solder and electroless- therefore, it is incumbent upon the investigator to maintain frequent Ni(P) under-bump-metallization has been studies by SEM, TEM, EDX contact with the agencies from which they want and/or have support. and e-probe microanalysis. Two findings are interesting. The first is In this discussion I will suggest ways in which this contact can be the enhanced crystallization of the electroless Ni(P), which has an developed, as well as describing various research initiatives at the NSF. amorphous structure in the as-plated state. The second is the lateral penetration of solder along the interface between the electroless Ni(P) 10:45 AM and the dielectric SiON substrate. The crystallization leads to the Collaborative Research Opportunity for New Faculty: Reza formation of Ni3P and Ni3Sn4 compounds. The penetration is accom- Abbaschian1; 1University of Florida, Dept. of Matls. Sci. and Eng., panied by the formation of Ni3Sn4 compound. The kinetics of the Gainesville, FL 32611-6400 USA crystallization and penetration will be presented. Materials science and engineering research in U.S. universities has been sponsored mainly by the federal government. The mission ori- 8:55 AM Invited ented agencies (mainly DOD and DOE) have provided about 60% of Evolution of Interfacial Morphology during Reaction of Cop- academic research. The agencies, however, have been shifting funds per and Electroless Nickel with Eutectic Pb-Sn Solder: A. S. toward applied and systems-oriented research. Many U.S. industries Zuruzi1; S. K. Lahiri1; 1Institute of Materials Research and Engineer- 19 have also eliminated central research laboratories to align their R&D ing, 10 Kent Ridge Crescent 119 Singapore Interfacial morphology of the intermetallics formed during the Conventional soldering technology is performed above the full reflow operation has an important effect on the wettability of the melting temperature region of low melting point solders; the massive underbump metallurgy and reliability of the solder joints. Evolution of trend toward Pb-free solders is not free from this type of temperature MONDAY AM the interfacial morphology during reflow is therefore of considerable restraint in terms of the choice of usable solders. The temperature interest for scientific as well as technological reasons, particularly limit narrows down the choice of usable alternatives to Sn-Pb solders from the viewpoint of reworking of assembled components. With the to tin-based alloys with eutectic or near eutectic composition. Off- present trend towards smaller and lighter electronic components, there eutectic alloys, however, with a high temperature liquidus line can be is currently a need in the microelectronics industry for direct attach- also used as solders in the partial melting temperature zone. The liquid ment of chip to organic substrates using the flip chip bonding tech- state and the solid state coexist in the partial melting temperature nique. However, the use of organic materials requires lower reflow zone, and the portion of liquid state is determined by the lever rule in temperatures during the assembly process than that needed for reflowing the phase diagram. To investigate the possibility of soldering in the conventional high Pb solder on chip terminal pads. Use of eutectic Pb- partial melting temperature zone, the hyper eutectic Sn-Pb alloys and Sn solder with electroless nickel underbump metallurgy, instead of the Cu plates were interconnected in the temperature range between the usual copper based metallurgy, is one of the methods which has re- eutectic temperature and liquidus temperature. Drying oven and con- cently been the subject of investigation by a number of researchers for ventional reflow soldering machine with hot-air reflow type were used. implementing a low temperature reflow process1,2. This paper will To verify the joint state, a microstructural observation was carried out address and compare the evolution of the interfacial morphology dur- using Scanning Electron Microscope (SEM). Shear test was conducted ing reaction of eutectic Pb-Sn solder with electroless nickel and cop- to check the strength of the soldered joint interconnected in the per. 1. J. Kloeser, K. Heinricht, K. Kutzner, E. Jung, A. Ostman, E. partial melting temperature zone. The test results showed a sustainable Zakel, and H. Reichl, Proc. ECTC, pp. 254-264 (1997). 2. J.W. Wang, strength of joint between hyper-eutectic solders and Cu substrate in- P.G. Kim, K.N. Tu, D.R. Frear, and P. Thomson, J. Appl. Phys., 85, terconnected in the partial melting temperature zone. 8456-8463 (1999). 10:15 AM Break 9:15 AM Invited 10:30 AM Invited Wetting of Low Melting Point Alloys on Metal Substrates: Timo- Development of Fluxes for Lead-Free Solders: Semyon Vaynman1; thy J. Singler1; Stephan J. Meschter1; 1SUNY Binghamton, Mech. Morris E. Fine1; 1Northwestern University, Dept. of Matls. Sci. and Eng., Binghamton, NY 13902-6000 USA Eng., Evanston, IL 60208 USA The wetting dynamics of low melting point alloys on metal sub- New lead-free solders, that contain zinc are promising candidates to strates is assessed using drop spreading. We observe a primary wetting replace near-eutectic tin-lead solders, because these solders have lower regime characteristic of many inert liquid systems and a secondary melting temperatures than those based on the tin-silver eutectic, pos- spreading regime characteristic of product-forming reactive systems. ses good mechanical and fatigue properties and are less expensive than We study the influence of temperature, and discuss its effects on sev- other alternatives to lead containing solders. However, the contact eral interesting spreading phenomena including the appearance of tran- angle on copper for Sn-Zn solders is rather high when utilized with sient solid phases. We explore the role of surface coatings, particularly fluxes used for Sn-Pb solders. A novel approach for flux development their effects on wetting kinetics and contact line morphology. to improve wetting of copper surface by tin-zinc eutecticis uses tin 9:35 AM containing organic compounds as an additive. These metallo-organics Application of Soldering in Partial Melting Zone to Grid Area decompose at soldering temperatures and produce metallic tin on the Package Using Pb Free Hyper-Eutectic Solders: Jun Seok Ha1; surfaces to be soldered. This process improves wetting of copper sur- Jae Yong Park1; Jae Pil Jung2; Choon Sik Kang1; 1Seoul National Uni- face by molten tin-zinc eutectic. versity, Matls. Sci. & Eng., Shillim-dong, Kwanak-gu, Seoul 151-742 10:50 AM South Korea; 2University of Seoul, Matls. Sci. & Eng., Jeonnong-dong, Reliability Investigation of Printed Wiring Boards Processed Dongdaemun-gu, Seoul South Korea with Water Soluble Flux Constituents: W. Jud Ready1; Laura J. Unlike the conventional soldering process, the partial melting sol- Turbini1; 1Georgia Institute of Technology, Matls. Sci. and Eng., 778 dering method is performed above the eutectic temperature and be- Atlantic Dr., Atlanta, GA 30332-0245 USA tween the eutectic point and the liquidus line. Because it is carried out An investigation was conducted to evaluate the effect on reliability in the mushy zone, the liquid and the solid phases co-exist. This method of water soluble flux and fusing fluid constituents used in the manufac- will enable us to use other alternative solders than the ones with eutec- ture of electronic product. The purpose of this program was to deter- tic composition and thus accelerate development and application of mine the mean-time-to-failure (MTTF) of FR-4 substrates processed new lead-free solders by offering us a broader range of alternatives. In with three different water soluble flux formulations. The fluxes incor- this study we applied lead- free hyper-eutectic solders (Sn-Bi Sn-In and porated hydrochloric acid, hydrobromic acid, a polyglycol and a Sn-Ag) to the partial melting soldering method and investigated the polyether. In order to determine the MTTF for conductive anodic possibility of bonding, metallurgical characteristics and microstruc- filament (CAF) growth a test coupon with variable hole-to-hole spac- tural evolution. A grid array-type substrate was fabricated for soldering ings was used. The variables being studied were (1) flux type, (2) con- in drying oven and conventional reflow soldering machine with hot-air ductor spacing and (3) operating voltage. Quantification of the effect reflow type. Various solder compositions were used in the liquid-solid of these variable is determined through a series of MTTF tests. In interface region and experiments were carried out in several tempera- addition to the electrical measurements, optical and scanning electron ture ranges. To determine wettability between partial melted solder microscopy (SEM) is used with energy dispersive X-ray spectroscopy and Cu substrate, wetting analysis test was conducted at each composi- (EDS) to determine the chemical nature of the CAF. tion-temperature variable set, and also the test results were compared with the case of full melted solder. After soldering, Scanning Electron 11:10 AM Microscope (SEM was used for observation of microstructure and its Effect of Plasma Cleaning on the Flip-Chip Bonding Proper- evolution during aging. To check the soldered joint strength, shear and ties of Si-Wafer/Bumps/Glass System: Soon Min Hong1; Chang tensile tests were performed. Bae Park2; Jae Yong Park1; Jae Pil Jung2; Choon Sik Kang1; 1Seoul National University, Divi. of Matls. Sci. and Eng., Shillim-dong, 9:55 AM Kwanak-gu, Seoul 151-742 Korea; 2University of Seoul, Matls. Sci. & The Possibility of Soldering in Partial Melting Zone Using Eng., Jeonnong-dong, Dongdaemun-gu, Seoul, South Korea Hyper-Eutectic Sn-Pb Alloys: Jae Yong Park1; Jun Seok Ha1; Jae Pil The flip chip provides the highest packaging density and perfor- Jung2; Choon Sik Kang1; 1Seoul National University, Matls. Sci. & mance and the lowest packing profile among other assembly methods. Eng., Shillim-dong, Kwanak-gu, Seoul 151-742 South Korea; 2Univer- As the packaging density grows high, however, the cleaning of flux sity of Seoul, Matls. Sci. & Eng., Jeonnong-dong, Dongdaemun-gu, used in conventional process becomes increasingly difficult. The flux Seoul South Korea residue can seriously affect the reliability and performance of flip chip assemblies by corrosion. In addition, the chemical solvent for flux 20 cleaning process can also cause the environmental problem which is a world-wide concern in recent years. The purpose of this research is to evaluate the fluxless flip chip bonding properties between Si wafers and Pressure Technology Applications in the Au-coated glass substrates in optical recording media application using Sn-Pb, Sn-Ag, Sn-Bi micro solder bumps. The solder bumps were elec- Hydrometallurgy of Copper, Nickel, troplated on the UBM(Cr/Cu)-deposited Si wafer and reflowed. The Cobalt and Precious Metals: Process pitch of the bumps was 50-150¥ ìm. Instead of flux, we used the Ar plasma cleaning to remove the oxides and other contaminants of Design and Engineering Considerations solder bumps and glass substrates before flip chip bonding. The in High Pressure Hydrometallurgy wettability of the Au-coated glass and UBM-coated Si wafer were estimated by meniscograph method and area of spread method. The me- Sponsored by: Extraction & Processing Division, Copper, chanical properties of the joint were examined by micro defect analy- Nickel, Cobalt Committee sis and micro tensile test. The bonding properties were compared with Program Organizers: James E. Hoffmann, Hoffmann and those of the bonding process using flux. The cross section of the solder Associates, Houston, TX 77242 USA; Norbert L. Piret, Piret joint and the intermetallic compounds between solder and coating & Stolberg Partners, Duisburg 47279 Germany materials were analyzed by optical microscopy and SEM. The effect of AM MONDAY flip chip process parameters, such as temperature profile, conveyor speed and atmosphere, on the bonding properties were also discussed. Monday AM Room: Lincoln C March 13, 2000 Location: Opryland Convention Center 11:30 AM Characteristics of the Sn-Pb Eutectic Solder Bump Formed via Fluxless Laser Reflow Soldering: Jong-Hyun Lee1; Jong-Tae Session Chairs: Jussi Asteljoki, Outokumpu Oy, Corporate Moon2; Yong-Ho Lee1; Yong-Seog Kim1; 1Hong Ik University, Metallu. Res. & Dev., Espoo 02201 Finland; Norbert L. Piret, Piret & and Matls. Sci., Sangsu-dong Mapo-Cu, Seoul Korea; 2Hyundai Elec- Stolberg Partners, Duisburg 47279 Germany tronics Company, Device and Semiconductor Rsch. Div., Ichon 467- 701 Korea With concerns on the environmental contamination and the reli- 8:30 AM ability of the electronic devices, many attempts were made to develop Process and Engineering Considerations in the Pressure a fluxless reflow soldering process in electronic packaging. In this Decopperizing of Copper Refinery Slimes: James E. Hoffmann1; study, the fluxless reflow soldering was conducted via heating the sol- 1James E. Hoffmann and Associates Company, P.O. Box 420545, Houston, TX 77242-0545 USA der bump using CO2 laser under controlled atmosphere. A solder disk was placed on the pre-tinned contact pad of the Si wafer and heated Oxidative pressure leaching is gradually supplanting all other tech- with the laser for reflow bumping. The effects of heat input, reflow niques for the decopperizing of copper refinery slimes. The reasons soldering atmosphere, solder compositions on the mechanical proper- for this include: much more rapid reactions, more compact equipment, ties and thermal stability of the solder bump were investigated. The and perhaps most important, a much lower final copper concentration heat input to a solder bump was changed from 20 to 60 J and the in the decopperized slimes. This paper will first discuss the reactions soldering atmosphere argon, helium, nitrogen, and air. The solders occurring during decopperizing, the acidity and temperatures encoun- used were Pb-Sn eutectic solder, Pb-Sn composite solder reinforced by tered and the techniques employed for discharging non condensable in-situ Cu6Sn5 dispersoids, and Sn-3.5%Ag. The reflow soldering under gasses. A spreadsheet is provided which allows adjusting the operating argon helium, nitrogen atmosphere resulted in spherical reflowed bumps. conditions depending upon raw (undecopperized) slimes composition, Microstructural observation of the reflowed bump showed a very thin solids concentration, and lixiviant composition. Typical process intermetallic layer formed at the solder/contact pad interface. Higher flowsheets and process equipment flowsheets are provided. heat inputs resulted in an excessive dissolution of the contact pad 9:00 AM metals and lower heat inputs in an insufficient reflow. Shear strengths Optimizing Gas Mass Transfer in Autoclaves: Peter Forschner1; of the reflowed solder joints measured were equal to those of the Stefan Land1; Ronald Klepper2; 1EKATO Ruhr-und, Mischtechnik reflowed joints formed in a furnace. A study on the mechanisms of the GmbH, Schopfheim, Germany; 2EKATO Corporation, Salt Lake City, fluxless reflow soldering via the laser heating were conducted by mea- UT USA suring the oxygen concentration distribution in the solder bump by In hydrometallurgy, pure gases like oxygen and hydrogen are used Auger Electron Spectroscopy as well as by estimating the thermal for oxidation and reduction. The gases are expensive and therefore stress developed during the laser heating by thermal modeling of the should be used efficiently. Non reacted gas can be recycled into the solder bump. liquid. Historically vortex gassing has been used, i.e. a mixing impeller 11:50 AM Invited close to the liquid surface entrains gas from the headspace into the Measurements of Metal/Polymer Adhesion Strengths in Mi- liquid through a gas vortex. Novel and more efficient methods are croelectronic Packaging: Jin Yu1; 1Korea Advanced Institute of surface gassing with up pumping impellers and self-inducing gassing Science and Technology, 3373-1 Kusong-dong Yusing-ku, Taejon, Ko- impellers. These alternative impeller systems are well established and rea common in the chemical industry, but have not been used until re- In plastic packages, residual stresses arising from thermal mismatches cently in hydrometallurgy. Gassing impellers act as internal compres- or pressures exerted by vaporized moisture often lead to the delamina- sors and increase the interfacial surface for a much higher mass trans- tion of metal/polymer interfaces. Modifications of polymer surfaces fer compared to alternate methods mentioned. In the paper results by rf plasma and oxidation treatments of metal surfaces before joining from lab and pilot tests and data from operated plants will be pre- dissimilar materials are commonly used to enhance the adhesion strength sented. The reactions with gases normally take place under moderate of the interface, which is measured by a plethora of techniques. In the to high pressure, therefore a safe enclosure with mechanical seals and present analysis, adhesion strength of Cu/Polyimide and Cu-based the safety “philosophy” is important. Experienced life and replace- leadframe/epoxy were measured using the peel test, pull-out test, and ment cycles will be reported. several fracture mechanics tests, and effects of the plasma and oxida- 9:30 AM tion treatments and near the crack tip stress states were investigated. Laboratory Autoclaves for Hydrometallurgical Research: Fathi Then, correlations between the peel strength, pull strength and the Habashi1; 1Laval University, Dept. of Min. and Metallu., Quebec City interface fracture toughness were presented, and the relations among G1K7P4 Canada the peel strength, interface fracture toughness and the work of adhe- Laboratory autoclaves for hydrometallurgical investigations are sion were discussed based on the X-ray measurements of plastic dissi- available in a variety of sizes, models, and materials of constructions. pation and the theoretical analysis. They vary in sizes from 25 ml to 2 liters for laboratory studies and 5 21 to 50 gallons for pilot plant work. They are essential tools for studying aqueous oxidation of sulfide concentrates, dissolution of oxide

MONDAY AM minerals at high temperature and pressure and hydrothermal precipita- Surface Engineering in Materials tion reactions. The maximum pressure and temperature at which any pressure vessel can be used will depend upon the design of the vessel Science I: Coatings/Films Synthesis and the materials used in its construction. Since all materials lose and Processes (SP)-I strength at elevated temperatures, any pressure rating must be stated in terms of the temperature at which it applies. A review of existing Sponsored by: Materials Processing and Manufacturing models and their accessories will be given. Division, Surface Engineering Committee 10:00 AM Break Program Organizers: Sudipta Seal, University of Central Florida, Advanced Materials Processing and Analysis 10:15 AM Center and Mechanical, Materials and Aerospace Engineer- Design Considerations in Autoclaving: Ir. Herman Pieterse1; 1Pieterse Consulting Inc., 6321 N. Calle Campeche, Tucson, AZ 85750 ing, Orlando, FL 32816 USA; Narendra B. Dahotre, Univer- USA sity of Tennessee Space Institute, Center for Laser Applica- The hydrometallurgical route, due to the fact that it often provides tions, Tullahoma, TN 37388 USA; Brajendra Mishra, increased recovery, reduced air and water pollution, and lower capital Colorado School of Mines, Kroll Institute for Extractive costs relative to roasting and smelting, is becoming the preferred route Metals, Golden, CO 80401-1887 USA; John Moore, Colo- for many metals. The design of autoclave circuits for various metals are discussed. Emphasis is placed on kinetics, energy balance, heating, rado School of Mines, Department of Metallurgy and cooling, retention, mixing, mass transfer, letdown, pumping, materi- Materials Engineering, Golden, CO 80401 USA als of construction, equipment selection. The leaching of copper, as one of the few applications where autoclaving has not been widely Monday AM Room: Canal B applied is highlighted. March 13, 2000 Location: Opryland Convention Center 10:45 AM Titanium Clad, High Pressure Acid Leach Autoclaves for Nickel Session Chairs: I. Manna, IIT, Metallu. and Matls. Sci. and Laterite Ore Processing: George A. Young1; 1Dynamic Materials, Metallu. Dept. Eng., Kharagpur, WB 721302 India; Brajendra Mishra, High pressure, acid leach autoclaves have been recently installed in Colorado School of Mines, Adv. Coatings and Surface Eng. Australia to process laterite ores of nickel. As a preferred design over Lab. Dept., Golden, CO 80401-1887 USA brick/lead lining all three projects have used titanium clad (integral lined), carbon steel pressure vessel autoclaves. The design features horizontal, chambered vessels with agitation. Based on various factors 8:30 AM Oxidation-Resistant Coatings for Molybdenum Electrodes: Sury including ore chemistry all three projects specified different grades of 1 1 1 1 titanium, i.e., gd. 1, gd. 11 and grade 17. This paper will review some Challapalli ; Earl Hixson ; John Moore ; Colorado School of Mines, of those grade selections decisions disclosed by the owners. Addition- Adv. Coati. and Surf. Eng. Lab., Dept. of Metallu. and Matls. Eng., Golden, CO 80401-1887 USA ally, performance of the titanium grades may be difficult to determine with one year or less service but some autoclave internal inspections The high-temperature oxidation resistance of molybdenum can be have been conducted. Comments from the operators on autoclave and significantly improved by coating it with MoSi2. But, at the high temperature of operation, silicon from MoSi2 diffuses into the molyb- material performance will be included. Dynamic Materials, Inc., Lafayette, CO supplied the titanium-clad steel for the autoclave ves- denum substrate and the oxidation resistance of the system deterio- sels for two of three projects, Bulong and Murrin-Murrin. ASC-E, rates. Further, because of the CTE mismatch between Mo and MoSi2, the composite breaks down and spalls on thermal cycling. To alleviate Adelaide Australia fabricated the vessels for all three projects including Cawse. Several other projects are awaiting final approval to proceed. the problem of the CTE mismatch, the CTE of MoSi2 is matched with that of Mo by the addition of 50 wt% SiC. But, the problem of silicon (and now additionally carbon) diffusion into the molybdenum substrate persists, changing the chemistry of the overlayer and deteriorating the oxidation resistance of the composite. Incorporating a diffusion barrier layer between the Mo substrate and the MoSi2+SiC composite layer on the top solved this problem. The newly developed amorphous diffusion barrier layer prevents diffusion of both carbon and silicon into the substrate. A number of problems still need to be resolved with respect to the diffusion barrier layer. These concern the chemistry, thermal stability, crystallization behavior, and cyclic oxidation resistance. Finite element modeling studies are also being undertaken to determine the optimal thickness of the individual layers, and the compositional gradient of the MoSi2+SiC composite to provide a tolerable residual stress level and also for optimal distribution of that stress in the overall coating system. These results will be utilized to optimize the diffusion barrier layer thickness. The present talk will review the recent results obtained and highlight the future investigations. Sup- ported by NSF under DMR Award # 9730775. 8:50 AM Invited Synthesis of Nanocrystalline Inconel 625 Powders by Cryomill- ing: Degang Cheng1; Rudy Rodriguez1; Mike Ice1; E. J. Lavernia1; 1University of California Irvine, Dept. of Chem. and Biochem. Eng. and Matls. Sci., Irvine, CA 92697-2575 USA The present paper report on a successful synthesis of nanocrystalline Inconel 625 powders by cryogenic high-energy ball milling (cryomill- ing). Commercially available Inconel 625 powders (Diamalloy 1005 AMDRY 625) is milled in liquid nitrogen for 8 hours. The characteris- 22 tics of the milled powders, i.e., morphology, self-agglomeration, pow- 10:20 AM Break der size, grain size and structure evolution during milling, were ana- 10:35 AM lyzed using X-ray diffraction (XRD), scanning electron microscopy Modeling of Combustion Flame Assisted Chemical Vapor Depo- (SEM) and transmission electron microscopy (TEM). sition of Diamond Thin Films: J. Kapat1; K. Elshot1; 1University 9:15 AM Invited of Central Florida, Dept. of Mech., Matls. & Aero. Eng., Orlando, FL Film Formation on Metals and Alloys by Thermal, Electrochemi- 32816-2450 USA cal and Plasma Oxidation: D. L. Cocke1; S. Promreuk1; D. G. Combustion flame assisted chemical vapor deposition (CFCVD) is Naugle2; R. B. Schennach1; 1Lamar University, Gill Chair of Chem. and of interest to researchers because of its simplicity. The main advan- Chem. Eng., P.O. Box 10022, Beaumont, TX 77710 USA; 2Texas tages of this method over other CVD methods include higher growth A&M University, Dept. of Physics, College Station, TX 77840 USA rates, low cost, and the potential to deposit a large area. In this study, Interfacial oxidation is an established approach to produce surface a numerical model has been developed for analyzing chemically react- thin films for catalysts, corrosion and ware protective coatings, and ing flow, mass and heat transport and reactions in CFCVD of a diamond electronic structures. The three main methods, thermal, anodic and thin film with a laminar, premixed C2H2/O2 flame. This model is used plasma, for oxidation of metallic substrates still lack an adequate fun- to numerically investigate the effect of different process parameters

damental physical-chemical models, that can allow film design, par- on the growth rate of the thin film. In this model, the flame is held AM MONDAY ticularly on alloys. Oxidation of alloys produce multicomponent ox- perpendicular to a Si substrate, where the film is deposited. The tem- ides with quite different structures depending on the conditions and the perature of the substrate is controlled independent of the flame tem- methods of oxidation. The three methods will be discussed in terms of perature as the substrate is attached to an externally cooled copper physical/chemical parameters that influence the chemical nature and substrate. As would be discussed later, the substrate is placed within the structure of the resulting oxides. The electrochemical processes that feather region of the flame for optimum diamond deposition. Chemi- occur during the materials reaction with a chosen environment will be cal model discriminates between graphitic and diamond phases through used to discuss the physical and chemical mechanisms involved. In- the use of different surface reactions so as to model the differential trinsic and extrinsic electric fields will be shown to influence the chemical etch and growth rates of these two phases. The focus of this paper is to and structural nature of the resulting oxide structures. Surface analysis present the effect of inlet gas composition and substrate to flame results [XPS (X-ray Photoelectron Spectroscopy) and ISS (Ion Scat- nozzle distance on thin film deposition rate. tering Spectrometry)] from the three oxidation methods applied to 10:55 AM metals and their binary and ternary alloys will be discussed. The result- Process Parameter Selection Rules and Direction of Maximum ing structures on the ternary and binary alloys will be discussed in terms Stress for Laser-Deposited Coatings: A. Kar1; Franz-Josef Kahlen1; of an evolving electrochemical model. 1University of Central Florida, Laser-Aided Manu., Matls. and Micro- 9:40 AM Process. Lab., Schl. of Optics and Ctr. for Rsch. and Edu. in Optics and Study of Operating Conditions on Electroless Plating of Nickel Lasers, Mech., Matls., and Aero. Eng. Dept., Orlando, FL 32816 USA for MEMS Application: Jin Huh1; Jae-Ho Lee1; 1Hong Ik University, This paper presents a set of design rules for a laser-aided powder Dept. of Metallu. Eng. and Matls. Sci., Seoul 121-791 Korea deposition process. A high power CO2 laser is used to melt the powder Electroless depositions of nickel were conducted in different bath and deposit a coating on a substrate. Dimensionless numbers charac- conditions to find optimum conditions of electroless nickel plating for terizing this powder deposition process are identified using fabrication of micro structures in MEMS applications. In LIGA or Buckingham’s P-Theorem. These dimensionless numbers are used to LIGA-like process, the operating temperature and pH is restricted and identify a range of values for the process parameters, such as the laser optimum operating conditions were different from conventional elec- beam power, spot diameter, substrate translation speed and powder troless deposition of nickel. And then to find optimum conditions, the flow rate, to achieve good quality coatings for different coating mate- effects and selectivity of activation method on several substrates were rials. The yield and ultimate strengths are examined for stainless steel investigated. The effects of nickel salt concentration, reducing agent, 304 (SS 304) coatings for three different processing conditions. These complexing agent and inhibitor on deposition rate was investigated. stresses are related to the dimensionless similarity parameters through The effect of pH on deposition rate and content of phosphorous in the operating conditions and physical dimensions of the deposit. Ex- deposited nickel was also observed. In optimum operating bath condi- periments conducted for SS 304 shows that the yield strengths are tion, deposition rate was 7?/hr at 60? and pH 10.0. The rate was close to the value of wrought material. Ultimate strengths are within decreased with stabilizer concentration. And then micro structures 80% of the corresponding values for wrought SS 304. The yield strength were fabricated with optimum bath condition. is found maximum in a given direction and this direction is oriented very close to the direction of material solidification. A mathematical 10:00 AM model is derived to calculate the residual stresses created during solidi- Electron Beam Enhancement of Composite Coatings: Vadim J. fication, accounting for directionally preferred solidification. Jabotinski1; Francis H. (Sam) Froes1; 1University of Idaho, Instit. for Matls. and Adv. Process., Moscow, ID 8384-3026 USA 11:15 AM Electron beam processing offers great technical and economic ca- Time-Dependent Relationships between Hf Dopant Incorpora- pabilities of improvement of composite coatings. Heating combined tion and HfCl4 Precursor Concentration during CVD-NiAl Dif- with radiation treatment offering by the electron beam processing fusion Coating Growth: G. Y. Kim1; Limin He1; Justin D. Meyer1; allows novel changes and modification in coating materials. This pa- W. Y. Lee1; 1Stevens Institute of Technology, Dept. of Chem., Biochem. per will consider fundamentals and applications of the electron radia- and Matls. Eng., Castle Pt. on Hudson, Hoboken, NJ 07030 USA tion in processing traditional and advanced coating materials including The incorporation behavior of Hf as a beneficial dopant during high-temperature superalloy-, intermetallic-, and ceramic-matrix com- aluminizing of a single crystal Ni alloy has been studied using a labora- posites applied by conventional techniques such as thermal spraying, tory-scale CVD reactor which can be mathematically modeled while high velocity oxygen fuel, plasma, laser, and physical and chemical emulating the actual manufacturing environment. The effects of vapor deposition. The specific effects leading to increase in the coat- proactively varying the gas phase concentration of the dopant precur- ing lifetime and wear, heat, and corrosion resistance will be identified. sor (HfCl4), as a function of aluminizing time, on the concentration Possible mechanisms for increasing the toughness, adhesion, bond and distribution of Hf in the NiAl coating matrix were examined to strength and reducing porosity and cracks will be discussed. understand the dynamic nature of the Hf doping process. Also, the process parameters and reactor conditions which led to the formation of Hf-rich particles and experimental irreproducibility were identified. These results will be discussed in the context of increasing the scale adhesion behavior of the Hf-doped NiAl coating, through model-based process optimization, for thermal barrier coating applications.

23 10:15 AM Break 10:30 AM

MONDAY AM Teaching Electronic, Magnetic and Microtechnology Education: Semiconductor and Mems Process- Optical Materials: A Symposium in ing for Undergraduate and Graduate Students at the Univer- sity of Washington: T. G. Stoebe1; T. P. Pearsall1; J. W. Rogers2; R. Memory of Professor Gregory E. B. Darling3; M. Afromowitz3; P. Yager4; 1University of Washington, Stillman: Session I Matls. Sci. and Eng., Seattle, WA 98195-2120 USA; 2University of Washington, Chem. Eng. Dept., Seattle, WA 98195-2120 USA; 3Uni- Sponsored by: Electronic, Magnetic & Photonic Materials versity of Washington, Elect. Eng. Dept., Seattle, WA 98195-2120 Division, Education Committee USA; 4University of Washington, Bioeng. Dept., Seattle, WA 98195- Program Organizer: Mark A. Palmer, Virginia Common- 2120 USA wealth University, Richmond, VA 23284-3015 USA An NSF-sponsored Combined Research and Curriculum Develop- ment project has allowed a team of faculty members at University of Washington to develop a series of courses and laboratories for students Monday AM Room: Bayou D interested in microtechnology. A sophomore class introduces students March 13, 2000 Location: Opryland Convention Center to electronic materials properties and processing; while a junior laboratory provides an introduction to clean room processes and equip- Session Chair: Mark Palmer, Virginia Commonwealth ment. A senior level class on semiconductor processing includes a University, Richmond, VA 23284-3015 USA laboratory in which the students make a MOSFET device. Graduate level courses include an introduction and laboratory class in MEMS and a process integration class. Details on course curricula and labora- 8:30 AM Opening Remarks tory development will be presented with lessons learned and advice for Mark Palmer, Session Chair; the development of similar programs. This program is supported by Robert Stull, Chair EMPMD the National Science Foundation. 8:40 AM 11:00 AM Invited A Brief Summary of Professor Stillman’s Contributions: John Introduction of Electronic Materials to Undergraduate Students Parsey in Materials Engineering: Matthias Militzer1; 1The University of British Columbia, Dept. of Met. and Matls. Eng., Vancouver, BC 8:45 AM Keynote V6T1Z4 Canada Bringing Electronic Materials to the Forefront of Engineering Electronic materials are taught to undergraduate students in materi- Education: Emily L. Allen1; 1San Jose State University, Dept. of als engineering at the University of British Columbia as a two credit Chem. and Matls. Eng. elective course in the fourth year. Since the students have in general no The design, selection, and processing of materials has always been background in quantum physics, the course is based on a predominantly critical to the practice of all engineering disciplines. As the study of descriptive approach to the subject with the objective being to develop traditional metallurgy transformed into the discipline of materials an understanding of basic concepts of specifications and making of science and engineering, a marriage with solid state physics and chem- semiconductor materials and devices. Semiconductor materials are in- istry occurred which brought new types of materials into being and troduced in relation to other materials (metals, ceramics, etc.) which allowed the unification of the discipline under the themes of structure, are stronger emphasized in the current curriculum. It is delineated why properties and processing. With the rise of the electronic age, the silicon is the material of choice. To motivate learning the basics of importance of electronic, photonic and magnetic materials has sky- electronic materials, selected optical and electronic devices (transis- rocketed in economic importance as well as in scientific and engineer- tors, photodetectors, etc.) are introduced throughout the course. An ing advances. MS&E curricula, and the service courses we offer to integral part of the course is to incorporate research aspects by a site other programs, have not always kept pace with the increased impor- visit to laboratory facilities (molecular beam epitaxy, clear room, etc.) tance of electronic materials. At San Jose State, we have initiated new and presenting selected results of research conducted by the instructor courses and programs in electronic materials, utilizing the appropriate or guest lecturers (e.g. on misfit dislocations). Further, assignment structure, properties, and processing approaches through laboratory work is included to perform simple calculations of materials aspects in experience. I will describe our electronic materials courses for Materi- the electronic industry. als Engineering majors as well as our service courses for Electrical, Computer and Chemical Engineering majors. Our new degree in Micro- 11:30 AM Invited electronics Process Engineering will be highlighted as well. I will stress Materials Science Education for the Information Age: Sharmila the learning styles-based pedagogical methods used to enhance the M. Mukhopadhyay1; 1Wright State University, Dept. of Mech. and learning environments of various courses. Matls. Eng., Dayton, OH 45435 USA Materials science, though regarded as an interdisciplinary field, has 9:30 AM Keynote historically evolved from metallurgy and this influence is very clear in Applets and Dynamic Multimedia Objects for Teaching and the traditional “materials” courses offered in most places. The typical Learning: Chu R. Wie1; 1State University of New York, Buffalo, NY focus is normally on the interconnected chain linking processing- USA structure-properties-performance, each link stressing more on me- Professor Chu is the Director for the Center for Active Learning of chanical & structural aspects than on any other. In this presentation, Microelectronics and Photonics at SUNY Buffalo, where he has devel- some ideas of possible additions and alterations to the existing cur- oped “Educational Java Applets in Solid State Materials,” he is also the ricula will be presented. These examples range from freshmen level Chair of the 2000 International Conference On Simulation and Multi- experiments across the entire engineering curriculum to focused gradu- media in Engineering Education Conference which will bring together ate (or upper-level undergraduate) courses such as “Electroceramics,” experts and colleagues who are interested in the fast growing area of “Electric Materials,” etc. that the author has introduced. Student re- modeling (both analytical and computational), simulation and visual- sponsiveness, degrees of success and special challenges will be discussed ization (and their comparison with experiments and observations), on a case by case basis. and simulation and multimedia-based engineering education. He will discuss his experience in developing these modules, using them in the classroom, and the activities of others as presented at the conference.

24 Matls. Sci. Dept., Thin Films Div., Petersenstr. 23, Darmstadt 64287 Germany Ultrafine Grained Materials: Chemical Vapor Synthesis and Low Pressure Flame Synthesis offer exciting opportunities for the preparation of nanocrystalline ceramic Fundamentals and Process powders with excellent control of the particle size, size distribution, Mechanisms: I degree of agglomeration, morphology and elemental distribution in the individual nanoparticles. In addition, porous and dense Sponsored by: Materials Processing and Manufacturing nanocrystalline coatings with functional gradients can be obtained Division, Powder Metallurgy Committee, Shaping and starting from the same metalorganic precursors. The design opportu- Forming Committee nities are similar to those common in CVD processing of thin films. Program Organizers: Rajiv S. Mishra, University of The synthesis method will be described including a model for the growth Missouri, Metallurgical Engineering, Rolla, MO 65409-0340 of primary particles and agglomerates. The resulting properties of nanocrystalline doped, two phase and coated ceramic composites will USA; S. L. Semiatin, Wright Laboratory, Materials Director- be discussed. ate, Dayton, OH 45440 USA; C. Suryanarayana, Colorado 9:50 AM School of Mines, Department of Metal and Materials AM MONDAY Synthesis and Characterization of Mechanically Amorphized Engineering, Golden, CO 80401 USA; Naresh Thadhani, and Shock Densified Nanocrystalline NiTi Alloy: Xiao Xu1; Georgia Institute of Technology, School of Materials Naresh N. Thadhani1; 1Georgia Institute of Technology, School of Science and Engineering, Atlanta, GA 30332-0245 USA Matls. Sci. and Eng., 778 Atlantic Dr., Atlanta, GA 30332-0245 USA In this study, mechanical amorphization (MA) and shock compac- Monday AM Room: Polk A/B tion (SC) experiments were performed on pre-alloyed Nitinol powders as well as elemental Ni and Ti powder mixture to prepare bulk March 13, 2000 Location: Opryland Convention Center nanocrystalline alloy compacts. The MA experiments were conducted using a SPEX 8000 mixer/mill. The pre-alloyed powders were ball- Session Chair: S. Lee Semiatin, Air Force Research milled in an Ar atmosphere and the elemental powders were alloyed Laboratory, Wright-Patterson Air Force Base, OH 45433- using Hexane. The SC experiments were performed using a single-stage 7817 USA gas gun at peak pressure of 5-9 GPa. The pre-alloyed compact showed crystallization to B2 phase with a nano-size microstructure. In contrast, amorphous microstructure was retained in the shocked compact 8:30 AM Introductory Remarks of elemental mixture, which crystallized to nanocrystalline NiTi B2 phase during post-shock thermal treatment. In this paper, we will 8:35 AM Invited present the results of shock densification and microstructural charac- Grain Boundaries of Nanophase Alloys Prepared by Mechani- teristics of the nano-structure formed in the bulk NiTi compacts. 1 1 1 cal Attrition: Brent Fultz ; Heather N. Frase ; California Institute of Research funded by ARO under Grant No.DAAG55-97-1-0163. Technology, Div. Eng. Appl. Sci., Mail 138-78, 1201 E. Calif. Blvd., Pasadena, CA 91125 USA 10:10 AM We report results on the structures of grain boundaries in Synthesis and Characterization of Ultrafine Ti Powders: S. nanocrystalline materials prepared by high energy ball milling. Results Amarchand1; T. R. Ramamohan1; P. Ramakrishnan1; 1Indian Institute are reported on average widths of grain boundaries, as determined from of Technology, Dept. of Metallu. Eng. and Matls. Sci., Bombay 400076 a combination of Mossbauer spectrometry measurements in conjunc- India tion with grain size measurements by x-ray lineshape analysis and The present work deals with a novel chemical solution synthesis TEM dark field imaging. More recently we have used small angle route, for the preparation of nanosize Ti powders, from Titanium neutron scattering to measure the densities of atoms and magnetic dioxide. Titanium dioxide is allowed to form a complex, titanium

moments within grain boundaries of nanocrystalline fcc Ni3Fe. Both catecholate precursor, in presence of ammonium sulphate and concen- densities are suppressed within the grain boundaries in comparison to trated sulphuric acid. The complex is filtered, washed with cold isopro- bulk material. From the nuclear scattering measured by SANS, we find pyl alcohol and dried. Hydrogenation of titanium catacholate is car- a distribution for the atom density in the grain boundary. Curiously, by ried out for different durations at various temperatures. Titanium hy- quenching nanocrystalline samples to low temperature we can alter dride is prepared by heating the titanium catacholate precursor at somewhat the grain boundary density. Quenching causes a change in 800°C in a furnace of 8E-6 torr vacuum and dehydrogenated in vacuum the atomic density of the grain boundaries, indicating a more discon- to get fine Ti powders. The characteristics evaluated by XRD, SEM tinuous transition in density between grain boundary and bulk material. and TEM indicated that the powders are pure Titanium with crystallite size in the range 45-60 nm. 9:00 AM Invited Localized CVD and the Ultrafine Grain Structure: Harris L. 10:30 AM Break Marcus1; Shay Harrison1; Leon Shaw1; James E. Crocker1; Lianchao 10:40 AM Invited 1 1 Sun ; University of Connecticut, Instit. of Matls. Sci., Storrs, CT Magnetization Reversal in Nanocomposite Exchange Spring 06269-3136 USA Magnets Observed Directly with a Magneto-Optical Indicator In high rate localized chemical vapor deposition using a laser beam Film: Robert D. Shull1; Alexander J. Shapiro1; Henrietta J. Brown1; to thermally decompose gas precursors the resulting grain size ranges Valerian I. Nikitenko2; Vladimir S. Gornakov2; J. Samuel Jiang3; A. from the near amorphous to a continuum of ultrafine grain sizes de- Inomata3; C. H. Sowers3; Samuel D. Bader3; 1NIST, Metallu. Div., 100 pending on processing parameters. This paper will describe the nature Bureau Dr., MS 8552, Gaithersburg, MD 20899-8552 USA; 2Institute of the grain sizes for various ceramic materials as a function of proof Solid State Physics, Russian Acad. of Sci., Chernogolovka, Russia; cessing and postprocessing conditions. The grain size characteriza- 3Argonne National Laboratory, MSD 223, 9700 S. Cass Ave., Argonne, tions were performed using Raman spectroscopy, NMR, TEM, X-ray IL 60439-4845 USA and other analytic approaches. The results will be described in terms of Epitaxial Sm-Co (350 Å)/Fe(500 Å) bilayer films were grown on Cr the various characterization approaches and related to modeling of (200 Å) buffered MgO (100) substrate by sputtering. Magnetic hyster- the processing variables. esis loops measured in a SQUID magnetometer showed characteristic 9:25 AM Invited exchange-spring behavior where the reversal of the soft Fe layer is Chemical Vapor Synthesis of Nanostructured Powders and Their pinned at the interface by the SmCo hard layer. For the first time in Properties: Horst W. Hahn1; 1Darmstadt University of Technology, such a material, the remagnetization process was observed directly using the magneto-optic indicator film (MOIF) technique. In order to 25 investigate the magnetic spin rotation process inside the bilayer during austenite grain size and the packet size, intercritical tempering to remagnetization, a 0.3 mm hole was made in the sample, and the disrupt lath alignment by interposing thermally stable austenite, and

MONDAY AM magnetostatic field (Hms) around the hole was visualized through the rapid thermal cycles that disrupt packet alignment. The mechanisms intensity changes of the double Faraday effect in a transparent indica- of refinement to ultrafine grain size will be discussed. Successful ex- tor film with in-plane anisotropy. Black and white contrast on oppo- amples of each grain refinement mechanism will be given. site sides of the microhole was observed, indicating the direction of 11:45 AM magnetization in the sample around the hole. We followed the line of Kinetics of Glass Formation and Nanocrystallization in Al-RE- contrast symmetry and analyzed the spin rotation process in the soft (TM) Alloys: Robert I. Wu1; Gerhard Wilde1; John H. Perepezko1; ferromagnetic component during remagnetization. This was compared 1University of Wisconsin-Madison, Dept. of Matls. Sci. and Eng., to the macroscopic magnetization as determined by a vibrating sample 1509 University Ave., Madison, WI 53706 USA magnetometer (VSM). Findings include direct observation of spin ro- Aluminum-rich amorphous alloys have attracted considerable at- tation in opposite directions for field applications slightly off either tention in recent years for their superior mechanical properties com- side of the easy axis of magnetization during conventional field rever- pared with conventional Al-based alloys. Often, the occurrence of a sal. When the field was aligned with the easy axis, no uniform spin precursor crystallization reaction during heating of rapidly solidified rotation was observed. During rotational hysteresis, a unique spin be- amorphous samples leads to the formation of microstructures with havior was observed: spin rotation was discovered to change sign with- finely dispersed nanocrystalline Al in an amorphous phase and offers out an accompanying change in the sign of the field rotation. The effective dispersion strengthening. While many amorphous alloys are reasons for these unusual remagnetization observations will be dis- produced by rapid solidification processing, mechanical intermixing cussed. also provides an alternative route to synthesize metallic glasses. In the 11:05 AM present study, characterization results on the Al-based metallic glasses The Relationship between the Reaction Conditions and the by TEM and modulated-temperature calorimetry (DDSC) indicate that Characteristics of the Metal-Bearing Ferrites Produced at Am- the glassy state has actually been attained by rapid melt-quenching as bient Temperature: Oscar Juan Perales Perez1; Yoshiaki Umetsu2; well as by deformation mixing. Annealing studies on the glassy samples Atsuo Kasuya1; Kazuyuki Tohji3; 1Tohoku University, Ctr. for Interdis. produced by different processing pathways indicate a completely dif- Rsch., Aramaki aza Aoba, Aoba-ku, Sendai 980-8578 Japan; 2Tohoku ferent nanocrystallization behavior and suggest that the quenched-in University, Instit. for Adv. Matls. Process., Katahira 2-1-1, Aoba-ku, nuclei originate from the rapid melt-quenching process. Moreover, Sendai 980-8577 Japan; 3Tohoku University, Dept. of Geosci. and glass formation appears to be controlled by the suppression of growth Tech., Aramaki aza, Aoba-ku, Sendai 980-8578 Japan of nuclei formed during rapid melt quenching for Al-based systems. Magnetite and various metal-bearing ferrites were produced directly With the aim of enhancing the mechanical properties of Al-based from aqueous solutions at 25°C by simultaneous control of the oxidiz- nanocrystalline materials, efforts have been focused upon increasing ing conditions for co-existing Fe(II) ion and pH. In this presentation, the particle density of nanocrystals by probing the crystallization the correspondence between the reaction conditions of formation of kinetics of the primary phase. A key issue in the controlled synthesis the ferrite in sulfate medium and its structural and magnetic character- of nanocrystalline Al microstructures is the capacity to control the istics will be discussed. The formation of a Zn-bearing ferrite was nucleation density that appears to be linked to quenched-in, pre-exist- selected as a first case study. The precipitates were characterized by ing clusters. Numerical modeling based upon the size distribution of the

XRD, EPMA, FT-IR, HRTEM and magnetic hysteresis loop measure- primary nanocrystals in partially crystallized Al88Y7Fe5 samples has ment. Furthermore, the analysis of the local structure of Fe and Zn been applied to analyze the nucleation kinetics during atoms by Extended X-ray Absorption Fine Structure Spectroscopy nanocrystallization in these metallic glasses. In addition, incorpora- (EXAFS) was also undertaken. It was found that the crystallinity, the tion of insoluble elements (e.g. Pb) during RSP has successfully yielded de-hydration of the intermediate compound and the diminution of the an increase in the nanocrystal particle density developed during pri- sulfate content in the nano-sized ferrites (average crystallite size 10 mary crystallization. The discovery has provided new microstructural nm) could be promoted by: (i) increasing the Fe/Zn mole ratio in the control in the study of heterogeneous nucleation kinetics in Al-based precipitates, (ii) a suitable duration of the aeration of the ferrite pre- metallic glasses. The support of the ARO (DAAG55-97-1-0261) is cursor suspension under alkaline conditions or, (iii) by aging of the gratefully acknowledged. precipitates at 25°C. In turn, EXAFS revealed that the ambient-temperature Zn-bearing ferrite exhibited a similar structure than the ceramic Zn ferrite produced at temperatures above 1000°C and Zn atoms were fully incorporated into the ferrite framework occupying the tet- AIME/TMS KEYNOTE ADDRESS rahedral sites. The mentioned effects were attributed to the suitable progress of the oxidation-hydrolysis reactions of Fe(II) species and Monday, March 13, 2000 the loss of water from the intermediate compound during the forma- 11:30 AM - 1:00 PM tion of the ferrite structure incorporating Zn atoms, which also ex- Room: Presidential Ballroom plained the observed enhancement in the saturation magnetization of the precipitates. The above results enable our proposal to be consid- FUTUREVIEW: A Look Ahead ered not only as a novel route to synthesize magnetic materials (ferrites) Speaker: Daniel Burrus, Burrus Research Associates, Inc. at ambient temperature but also a promising alternative to remove metal ions and produce re-usable precipitates in the treatment of large Thanks to recent innovations in science and technology we are at the volumes of polluted effluents. gateway to a renaissance in materials technology, in terms of not only developing new applications, but also in terms of the industry itself. 11:25 AM Although we are at a time of tremendous opportunity, we are at the Thermal Mechanisms of Grain Refinement in Lath Martensi- same time faced with problems of equal magnitude. This presentation tic Steels: John William Morris1; Zhen Guo1; 1University of Califor- will provide you with valuable insight into how best to capitalize on nia, Dept. of Matls. Sci., Berkeley, CA 94720 USA present and future opportunities, while artfully minimizing problems The effective grain size of a martensitic steel with a dislocated lath along the way. substructure is the pertinent coherence length. For intergranular fracture this is the prior austenite grain size, for transgranular cleavage, the packet size in the (100) plane, and for slip-dominated processes, the packet size in (110). To achieve exceptional properties, it is important to refine the effective grain size into the submicron range, and it is desirable to do this with thermal processes that can be applied to plate product. Three mechanisms are available. In increasing order of effectiveness they are: alternate thermal cycling to refine the prior 26 MONDAY PM

Recently computational tools such as Thermo-Calc have been made increasingly use of to expedite alloy development and process im- Advanced Technologies for Superalloy provement, thus cutting cost/time cycles of experimental trials. Three Affordability: Superalloy Modeling- concrete examples are presented illustrating the capabilities of the current modeling software: (1) the development of a new weld wire for Processing, Microstructure and Prop- automotive exhaust systems, (2) the development of a new alloy for erty superheater tubing in advanced power plants, (3) the improvement of Sponsored by: Structural Materials Division, High Tem- heat treating processes of high performance alloys. It is emphasized, however, that Thermo-Calc requires from the user also a sound knowl- perature Alloys Committee edge of the physical metallurgy of the system in order to ensure effec- Program Organizers: K. M. Chang, West Virginia Univer- tive usage of this tool. PM MONDAY sity, Mechanical & Aerospace Engineering, Morgantown, 3:10 PM WV 26506 USA; K. R. Bain, GE Aircraft Engines, Cincinnati, Precipitation of γ’ from γ during the Weld Thermal Cycle: OH 45215 USA; D. Furrer, Ladish Company, Cudahy, WI Recent Results of APFIM Characterization and Modeling: S. S. 53110 USA; S. K. Srivastava, Haynes International, Babu1; S. A. David1; J. M. Vitek1; M. K. Miller1; 1Oak Ridge National Kokomo, IN 46904 USA Laboratory, 1 Bethel Valley Rd., Oak Ridge, TN 37831 USA Welding plays an important role in economical reuse and reclamation of used and failed nickel-base superalloy blades. It has been shown Monday PM Room: Canal C that it is possible to weld these alloys with high-energy processes such March 13, 2000 Location: Opryland Convention Center as electron beam and laser welding. The microstructure development during weld thermal cycles plays a vital role in the weldability and the Session Chairs: Krishna Srivastava, Haynes International, service properties. In this paper, the precipitation of γ’ phase during Kokomo, IN 46904 USA; Michael Fitzpatrick, Solar Turbines simulated weld cooling conditions was studied with transmission electron microscopy and atom probe field ion microscopy and atom probe Inc., Adv. Tech. Matls. and Process., San Diego, CA 92186 tomography. The results indicate non-equilibrium alloying elements USA partitioning between γ and γ’ phases. The morphology of γ’ precipitates was irregular compared to that of cuboidal shape in the heat- treated condition. The experimental results will be compared with 2:00 PM Invited thermodynamic and kinetic calculations. This research is supported by Application of Calphad Methods to Ni-Based Superalloys: Nigel the Division of Materials Sciences, U.S. Department of Energy under Saunders1; 1Thermotech Limited, Surrey Tech. Ctr., The Surrey Rsch. contract DE-AC05-96OR22464 with Lockheed Martin Energy Re- Park, Guildford, Surrey GU25YG UK search Corporation. Thermodynamic calculations using the CALPHAD route are becoming increasingly used for practical purposes [1]. This paper will 3:30 PM describe a number of applications of the methodology to Ni-based Solidification Diagram of Ni-Cr-Fe-Nb System: Wei Chen1; superalloys, with particular emphasis on issues associated with Wanhong Yang1; Keh-Minn Chang1; Sarwan K. Mannan2; John J. affordability. These applications will include its use in helping to de- deBarbadillo2; 1West Virginia University, Dept. of Mech. and Aero. fine composition specifications, monitoring of sigma formation, criti- Eng., P.O. Box 6106, Morgantown, WV 26506-6106 USA; 2Special cal temperatures and heat treatment windows during processing, more Metals Corporation, 3200 Riverside Dr., Huntington, WV 25705 USA efficient and speedy alloy design and calculation of critical input pa- Macroscopic solidification segregation is one of the key issues in rameters for use in process modeling. [1] N.Saunders and A.P.Miodownik the production of high quality premium ingots of Ni-base superalloys, “CALPHAD-a Comprehensive Guide” (Elsevier Science, Oxford, 1998). such as alloys 718, 706 and 625. These commercial alloys contain certain amounts of Nb, which is associated with the formation of 2:25 PM Invited eutectic phases like Laves and Ni Nb. Quarternary Ni-Cr-Fe-Nb alloy Phase Compositions in Alloy 718: A Comparison between APT/ 3 system is selected as the model alloy system to study the fundamentals APFIM Measurements and Thermodynamic Predictions: M. K. solidification behaviour of multicomponent industry alloys. Several Miller1; S. S. Babu1; 1Oak Ridge National Laboratory, Mets. and Cer. experimental alloys consisting of various combinations of Cr, Fe and Div., 1 Bethel Valley Rd., Oak Ridge, TN 37831-6376 USA Nb were prepared. The elemental segregation profiles and terminal In order to improve the properties of nickel-based superalloys, it is solidification phases were determined by DTA and SEM-EDS analysis. essential to determine the partitioning behavior of the solute additions Two types of eutectic products, Ni Nb and Laves, exist in the within the microstructure. The techniques of atom probe field ion 3 interdendritic region. A computational thermodynamic software, microscopy (APFIM) and atom probe tomography (APT) permit the Thermo-Calc, was employed to calculate the solidification constitu- solute partitioning and compositions of the coexisting phases to be tion diagram of Ni-Cr-Fe-Nb system. The calculated phase boundaries determined with near atomic resolution in these complex engineering were verified using experimental results. A simplified thermodynamic alloys. In Alloy 718, these techniques have revealed that the second- database was developed to predict the solidification path and elemen- ary precipitates have a dual nature and are combination of the DO - 22 tal partitioning of the model alloys. The obtained diagram can help to ordered Ni (Nb,Ti) ‘ phase and the L1 -ordered Ni (Al,Ti,Nb) g’ phase. 3 2 3 understand the solidification segregation of Nb-containing superalloys The experimentally determined compositions of these phases will be with complex chemical compositions. compared to thermodynamic predictions. This research was sponsored by the Division of Materials Sciences, U.S. Department of Energy, 3:50 PM Break under contract DE-AC05-96OR22464 with Lockheed Martin Energy 4:05 PM Invited Research Corp. and through the SHARE Program under contract DE- Oxygen Enhanced Crack Growth in Nickel-Based P/M Super- AC05-76OR00033 with Oak Ridge Associated Universities. alloys: Robert P. Wei1; 1Lehigh University, Dept. of Mech. Eng. and 2:50 PM Mech., 7 Asa Dr., Bethlehem, PA 18015 USA Capitalizing on Computational Tools in Alloy and Process De- As a part of a study to elucidate the role of niobium on crack growth velopment: Michael G. Fahrmann1; G. D. Smith1; 1Special Metals in oxygen at high temperatures, three powder metallurgy (P/M) alloys, Corporation, 3200 Riverside Dr., Huntington, WV 25705 USA with nominal composition similar to alloy IN-100, but with 0, 2.5 and 27 5 wt. pct. niobium, were investigated. These alloys are γ strengthen and were designed to suppress the formation of γ’ precipitates. The volume fraction of precipitates in the alloys is comparable at about 53 MONDAY PM pct. The alloys were tested in high-purity oxygen and argon, under Aluminum Reduction Technology: Cell sustained-loading, at 873, 923 and 973 K. Companion microstructural Development/Operation and surface chemistry studies were also conducted. In this paper, the Sponsored by: Light Metals Division, Aluminum Committee data on the kinetics of crack growth will be summarized and compared Program Organizers: John Chen, University of Auckland, against those for Inconel 718. The mechanisms for crack growth and the role of niobium and of other elements will be discussed in terms of Department of Chemical & Materials Engineering, the ensemble of results. Auckland, New Zealand; Georges J. Kipouros, Dalhousie 4:30 PM University, Department of Mining and Metallurgical Temperature Evolution during High-Cycle Fatigue in ULTIMET Engineering, Halifax, NS B3J2X4 Canada Superalloys: L. Jiang1; P. K. Liaw1; C. R. Brooks1; H. Wang2; D. L. Klarstrom3; 1University of Tennessee, Dept. of Matls. Sci. and Eng., Monday PM Room: Sewanee 427-B Dougherty Eng. Bldg., Knoxville, TN 37996-2200 USA; 2Oak March 13, 2000 Location: Opryland Convention Center Ridge National Laboratory, 1 Bethel Valley Rd., Oak Ridge, TN 37831- 6064 USA; 3Hayes International Inc., 1020 W. Park Ave., P.O. Box 9013, Kokomo, IN 46904-9013 USA Session Chair: Alton Tabereaux, Reynolds Metals Com- The infrared (IR) thermography, as a nondestructive technique, was pany, Corp. Rsrch. and Dev., Muscle Shoals, AL 35661-1625 used to investigate the fatigue damage of ULTIMET alloy, a cobalt- USA based superalloy. The cumulative fatigue damaging process was characterized by the temperature changes during high-cycle fatigue. A noncontact, high-speed, and high-resolution IR thermoimaging sys- 2:00 PM Invited tem was capable of monitoring the temperature oscillation corre- Development of High Amperage Prebaked Cells in China: S. sponding to the change of the mechanical state during high-cycle Z. Feng2; Z. X. Leng2; Yiren Gan1 1Zhengzhou Light Metal Research fatigue testing. A thermodynamic model is presented for predicting Institute, Shangjie, Zhengzhou China; 2Guizhou Aluminium Plant, the thermal-mechanical response. The predicted temperature response Guiyang, Guizhou China was found to be in good agreement with the experimental results. Aluminium production capacity in China is over 2.5 million tonnes/ annum, but the main type of pots is Soderberg pot. In order to change 4:50 PM the backward situation, a development program for high amperage The Effects of Heat Treatment on Time-Dependent Fatigue point-fed prebaked pot has been carried out since the latter part of the Crack Propagation in a Low Thermal Expansion Superalloy 1970’s. A laboratory has been set up to carry out basic research work INCONEL 783: Longzhou Ma1; Keh-Minn Chang1; Sarwan K. Man- on electro-magnetic-hydrodynamics, thermal balance and other pa- nan2; 1West Virginia University, Mech. and Aerospace Eng. Dept., rameters in aluminium pots. It includes modeling tests, measuring meth- P.O. Box 6106, Eng. Sci. Bldg., Morgantown, WV 26506-6106 USA; ods in laboratory and industrial pots, development of mathematical 2Special Metals Corporation, 3200 Riverside Dr., Huntington, WV modeling and calculation program. After testing and verifying the 25705 USA results in industrial pots, new types of 186kA and 280kA pots have Recently developed alloy 783 (nominal composition of Ni-34Co- been developed and tested successfully in pilot plants. Based on the β 26Fe-5.4Al-3Nb-3Cr) is precipitation strengthened by Ni3Al-type test results, 2 lines of 186kA pots have been set up and are in produc- γ and NiAl-type phases. Due to its low coefficient of thermal expan- tion, another 2 lines are in construction and 2 lines of 280kA pots are sion, high strength, and good oxidation resistance, alloy 783 is used for planned for construction. This technology will be used in new alu- casings and bolting applications in gas turbines. Commercial alloy 783 minium plants in China. A 320kA testing line will be put into produc- ° plate was rolled in the laboratory to 50% reduction at 870 C. A part of tion soon. the plate was direct aged and the other part was annealed at 1121°C and aged. This was followed by fatigue crack propagation of the aged 2:30 PM materials at 300°C, 450°C, 600°C, and at room temperature. Tests Danjiangkou-A Step Forward: Hugh McLaughlin1; Guo Xing2; were carried out at 10 Hz and 1/3 Hz using sinusoidal loading and also 1VAW Aluminium-Technologie GmbH, P.O. Box 101554, Neuss D- under a 100-second hold time using trapezoidal waveform. Interest- 41415 Germany; 2Danjiangkou Aluminum Industry Company, Hubei ingly, the crack growth rates of direct aged and annealed plus aged Province, China materials were not significantly different. VAW’s former Toeging 1 smelter in Germany has been purchased by the Danjiangkou Aluminium Industry Company, Ltd. and successfully 5:10 PM relocated to China. The startup of these facilities during 1999, sup- Effects of Heat Treatments and Thermomechanical Processing ported by VAW-ATG, has upgraded and expanded the existing Soderberg on the Beta and Gamma Phases in Inconel 783 Alloy: Mohindar plant. Today it is one centered around a 100 pot, highly efficient, end S. Seehra1; A. Manivannan1; Codrin Cionca1; L. Ma1; Keh-Minn Chang1; to end prebake, complete with a modern computer control system. 1West Virginia University, Morgantown, WV 26506 USA This low cost modular design was producing aluminum only 14 months β Inconel 783 is a low CTE alloy in which the role of phase is after start of construction. This 114.5 kA potline operated consis- β γ important but not well understood. Here, changes in the and phases tently at over 94% current efficiency with a power consumption of in alloy 783 upon heat treatments and thermomechanical processing 13.4 kWh/kg during its former life. Its sale to China, due to power (TMP) are studied using x-ray diffraction (XRD), thermogravimetric constraints in Germany, and its efficient reassembly and startup reflect analysis (TGA) in a magnetic field and microstructural observations. favorably on the design and operational stability of this cell. The pots ° TMP included: HR0 (hot rolled to ¾ inch at 2000 F); HR1 (HR0 rolled are equipped with center hoppers for alumina, aluminium fluoride, and ° ° 50% at 1600 F); HR2 (HR0 rolled 50% at 1850 F) and HR3 (HR0 crushed bath. Crust breakers and point feeders are incorporated in the ° rolled 50% at 2100 F). Heat treatments included normal treatment hoppers. The VAW technology featuring pot design and hardware as (NT) and direct aging (DA). HR0DA contains only the -phase and no well as the ELAS pot control system bring an era of new life to the ° magnetic transition (Tc) above 25 C. Samples HR1DA, HR2DA and aluminium smelting industry in central China. This paper presents β γ ° ° HR3DA have and phases and two Tc’s near 390 C and 490 C. For some details around this project and emphasises the extreme interest β ° HR1NT and HR2NT, phase is weak and Tc at 390 C is lowered to within China to upgrade their aluminium smelting facilities. 352°C. These results will be discussed relative to thermodynamic calculations on phase formation and phase chemistry. 2:55 PM Satisfying Financial Institutions for Major Capital Projects: Jan Heintzen2; Robert Paul Harrison1; 1Hatch, Light Metals Grp., 5 Place Ville-Marie, #200, Montreal, Quebec H3Z3R9 Canada; 2Beddows 28 & Company, Aluminum Projects, 5 Place Ville-Marie, Montreal, Que- 4:45 PM bec H3B2G2 Canada Design of Shunt Rheostat for Coke-Bed Preheating of Alu- Major capital investments in the aluminum sector require signifi- minium Reduction Cells: S. A. Mohamed1; F. M. Ahmed1; 1Alu- cant financing, often in the hundreds of millions of dollars. Lenders minium Company of Egypt, Rsrch. and Dev., Naga-Hammadi, Egypt are understandably conservative about transactions of this magnitude, Coke-bed preheating is one of the most popular methods to preheat and impose not only contractual and financial obligations but techni- aluminium reduction cells. The preheating by this method can be cal ones as well. A project must be technologically sound, properly achieved with partial or full line current. To achieve preheating with- staffed and managed, and environmentally acceptable-to the satisfac- out full line current, shunt resistance is employed. The design proce- tion of the banks-before they will disburse the required capital. With dure of shunt resistance includes, selection of material, collection of permission from the Billiton Group, two recent examples are pre- preheating and cell design data, thermoelectric calculations in addition sented to illustrate these concepts: the construction of the Hillside to the assembly and detail drawings. In this paper, the steps taken to smelter in South Africa, and the acquisition of Worsley Alumina in design two different groups of shunt resistance fox preheating of 200kA Australia. end to end, prebaked anode cell is explained. The results of applying 3:20 PM the different designs in preheating of aluminium cells are discussed. The Effect of Anode Spike Formation on Operational Perfor- 5:10 PM MONDAY PM MONDAY mance: Bernd Rolofs1; Neal Wai-Poi1; 1Hoogovens Aluminium Reduction Cell Technology Development at DUBAL through Huttenwerk GmbH, Postfach 101154, Voerde D46549 Germany 20 Years: A. J.M. Kalban1; Y. A.M. Al Farsi1; A. S.S. Binbrek1; 1Dubai Since the start-up of the Voerde smelter in 1970, several upgrades Aluminium Company Limited, P.O. Box 3627, Dubai United Arab and retro-fits of the existing P69 technology have been completed. Emirates These include, the introduction of bigger anodes and the implementa- The Dubai Aluminium Company Limited (DUBAL) smelter com- tion of Celtrol2 computer process control system. These and other menced operations in 1979 with 3 potlines comprising 360 prebaked modifications enabled the Voerde smelter to make significant improve- cells at 150 kA and producing 135,000 tonnes of aluminium annually. ments in cell performance and operations, resulting in e.g.94+% cur- By 1990, a series of continuous, innovative improvements to the cell rent efficiency and an average cell life of 2600 days. However, since components and operational practices radically transformed the origi- the conversion from wet to dry scrubbing in 1992, the smelter has nal cell technology to operate at 180 kA. An expansion of 139 cells in experienced a persistent problem with carbon dust levels. As a conse- Potline 4 resulted in a total of 499 cells producing ~ 250,000 tonnes quence, the anode spike frequency has increased significantly. The aluminium annually. By 1996, having developed, jointly with Comalco, spiking has had a negative impact on current efficiency, typically a and tested five prototype CD-200 reduction cells at 200 kA, DUBAL 1.6% loss and resulted in a greater variation in operational parameters. installed 240 cells in Potline 5. Total cells thereby increased to 739 Therefore, several trials have been conducted to investigate the origin and annual production to 375,000 tonnes. In 1999, another 240 CD200 of the carbon dust, the impact on cell operations and the influence of cells were commissioned in Potline 6 increasing the cell population to operating practices on spiking. 984 cells and annual production to 536,000 tonnes of high quality 3:45 PM Break aluminium whilst generating 1400 MW power through natural gas- fueled turbines. This paper tracks 20 years of DUBAL’s continuous 3:55 PM advancement in reduction cell technology, both in terms of improve- Aspects of Field Studies on Hall-Heroult Cells: Nolan E. ments and development. Richards1; 1Richards Consulting, 117 Kingswood Dr., Florence, AL 35630 USA Whenever a meaningful database for the performance of a cell representative of a potline is needed, a comprehensive characteriza- Automotive Alloys 2000: Fundamental tion of such a cell should be considered. Such a characterization is even more desirable when modifications to any aspect of the cell, e.g., bath Sponsored by: Light Metals Division, Aluminum Committee chemistry, anode area, line current, thermal insulation, protocol for Program Organizer: Subodh K. Das, University of alumina additions are planned. Comprehensive field studies are also Kentucky, College of Engineering, Center for Aluminum important in ensuring that the performance of a cell representative of Technology, Lexington, KY 40506-0043 USA a greenfield potline falls within the prescribed targets. Recommenda- tions are given for an array of in situ field measurements and methods for conducting them. Typical results and sensitivities are presented. Monday PM Room: Knoxville A Examples of the data obtained from a selection of cells are shown and March 13, 2000 Location: Opryland Convention Center discussion offered of the synergism and interpretation of some results. 4:20 PM Session Chair: Subodh K. Das, University of Kentucky, Advanced Solid Bath Transport at DUBAL: W. A.R. Al-Sayed1; J. College of Eng., Lexington, KY 40232 USA Ifju2; I. Del Porto2; M. Moni2; 1Dubai Aluminium Company, P.O. Box 3627, Dubai United Arab Emirates; 2Techmo Car Spa, Via R. Colpi, 2:00 PM Limena(PD) 35100 Italy Recycling the materials extracted from the cells and removed tem- Precipitation of Iron Containing Phases in 319 Type Alloys 1 1 porarily from the smelting process due to periodic operation of the during Solidification: Jacob W. Zindel ; Larry A. Godlewski ; Wil- liam T. Donlon1; 1Ford Motor Company, Ford Rsch. Lab., P.O. Box prebaked anodes is compulsory in order to maintain high efficiency and performance of the primary aluminium smelting. Utilization of 2053, Dearborn, MI 48121 USA the solid bath requires a series of operations including its handling, Al-Si-Cu-Mg alloys, commonly referred to as 319, are widely used in the production of cast aluminum automobile powertrain compo- processing and transport which has to be fulfilled in a safest way and lowest possible losses. A tailor-made and specially designed vehicle has nents. Secondary alloys such as these contain iron as an impurity as a been developed for the Dubai Aluminium Company Ltd. in close coop- result of contamination in the recycling stream. During solidification, iron containing intermetallic compounds form which have been attrib- eration with the operation experts aimed at efficient handling, fast and safe transport taking into account environment protection and uted to increasing the propensity for microporosity formation, de- good working conditions for the operators. This paper describes the creasing ductility, and reducing fatigue strength of castings. In an effort to understand how to control the formation of these phases, work work done and economical effect in relation to the use of vehicles with innovative concept of design named Easy Truck. has been conducted to characterize their nucleation and growth. This study consisted of interrupting the solidification of 319 alloy samples with different Fe concentrations by quenching them into an iced-brine bath. Samples with 0.40, 0.65, and 0.95 wt.% Fe were quenched at 29 various solid fractions to determine when the various iron compounds ments, differential scanning calorimetry (DSC) and transmission elec- precipitate. Typically, two Fe-containing phases are observed in these tron microscopy (TEM). Electrical resistivity measurements were found alloys, a cubic phase, alpha, with the approximate stoichiometry of

MONDAY PM to be very sensitive to the heat treatment procedure and can be used to Al15(Fe,Mn)3Si2 and a monoclinic phase, beta, with the approximate provide information on the formation of solute clusters and their stoichiometry of Al5FeSi. In the 0.4 wt.% Fe alloy, alpha appeared to subsequent dissolution during artificial aging. It was also found useful to have precipitated after the nucleation of the Al-Si eutectic. No other conduct DSC traces after different levels of artificial aging to follow iron compounds were observed in this alloy. In the 0.65 and 0.95 wt.% the sequence and kinetics of precipitation. The results from this work Fe alloys, a tetragonal phase, delta (Al4Si2Fe), was observed to pre- confirmed that natural aging significantly reduced the strength at short cipitate near the liquidus followed by alpha and beta precipitation at a artificial aging times. As the level of natural aging was increased, this temperature above the Al-Si eutectic reaction. The temperature of the effect was increased. However, for natural aging times greater than thermal arrest due to Fe compound precipitation increased with in- approximately 7 days, a further increase in natural aging time had a creasing Fe concentration. much smaller effect. It is thought that the formation of solute clusters 2:25 PM during natural aging reduces the solute available for precipitation at Improving Stress Corrosion Cracking in Al-Mg Alloys: John S. higher temperatures. It appears that dissolution of clusters in order to Vetrano1; M. J. Danielson1; D. R. Baer1; R. H. Jones1; 1Pacific North- free up solute for precipitation is the rate controlling process during west National Laboratory, MSIN P8-16, P.O. Box 999, Richland, WA the initial stages of artificial aging. 99352 USA 3:30 PM Break The use of Al-Mg alloys with Mg levels of greater than 3.5 wt.% for automotive structural components is hampered by their susceptibility 3:50 PM to stress corrosion cracking (SCC) in salt water. Segregation of Mg to The High-Cycle Fatigue and Fracture Response of Al-Cu-Mg 1 1 2 1 grain boundaries causing precipitation of the Al3Mg2 (b) phase during Alloy 2524: T. S. Srivatsan ; D. Kolar ; P. Magnusen ; The Univer- low-temperature thermal exposure (sensitization) has been shown to sity of Akron, Dept. of Mech. Eng., Akron, OH 44325-3903 USA; 2 be the primary cause of SCC in these alloys. We have utilized alloying Aluminum Company of America, Alcoa Tech. Ctr., 100 Technical additions and tailored heat treatments to lessen the SCC susceptibility Dr., Alcoa Center, PA 15069 USA in Al alloys containing up to 7% Mg following sensitization heat The design of structural components for the newer generation of treatments at 175°C. Alloying additions studied include Zn, Mn and Sc, civilian and military aircraft demands satisfactory performance from at levels allowing the study of solid solution and precipitate effects. the material under conditions of cyclic stress amplitude and strain Both Mn additions and a slower cooling rate from the initial annealing amplitude control, and an extended service life. In this connection, a prior to sensitization treatment reduced the SCC susceptibility as mea- study has been made to understand the influence of test temperature sured by the ASTM G-67 weight loss tests. Allowing the samples to on cyclic stress amplitude response characteristics and fatigue life of cool in the furnace reduced the SCC susceptibility compared to those aluminum alloy 2524. Test specimens of the alloy were cyclically samples that were water quenched after annealing. Additionally, the deformed over a range of stress amplitudes at both ambient and el- addition of 0.09 wt.% Cu reduced the SCC susceptibility although evalu- evated temperatures. In this presentation, the stress response charac- ation is still in progress. The effects of alloying additions and thermal teristics and resultant fatigue properties of the alloy will be highlighted treatment on the SCC behavior of Al-7 wt.% Mg alloys are thought to in light of the competing and mutually interactive influences of cyclic be due to a change in grain boundary b phase precipitation. Work stress amplitude, intrinsic microstructural effects, matrix deformation supported by the Materials Division, Office of Basic Energy Sciences, characteristics and final fracture behavior. Research supported by State U.S. Department of Energy under Contract DE-AC06-76RLO 1830. of Ohio: Board of Regents (Columbus, OH, USA), and The University of Akron (Akron, OH, USA). 2:50 PM The Precipitation Sequence in 6111 Aluminum Alloy: Weifang 4:10 PM Miao1; David E. Laughlin1; 1Carnegie Mellon University, Dept. of Fatigue Performance of Mechanically Surface Treated Alumi- 1 1 Matls. Sci. and Eng., 5000 Forbes Ave., Pittsburgh, PA 15213 USA num and Magnesium Alloys: Lothar Wagner ; Matthias Hilpert ; 1 The hardening of 6111 aluminum alloy is realized through the pre- Technical University of Brandenburg at Cottbus, Chair of Matls. Tech. cipitation of various metastable precipitates, therefore a more in depth and Physical Metallu., P.O. Box 101344, Cottbus D-03013 Germany understanding of the precipitation sequence is very important to achieve The effect of shot peening and roller-burnishing on the HCF behav- the full strengthening potential of the alloy. While the focus of previ- ior of two widely used automotive light-weight alloys (6061 Al and the ous investigations of the precipitation hardening behavior in Al alloy magnesium alloy AZ 31) was studied. For shot peening and roller- 6111 has been on the aging response, many details of the precipitation burnishing, the main process parameters Almen intensity and rolling process remain unclear. In this paper, the precipitation sequence in force, respectively were widely varied to optimize fatigue performance. Cu-containing Al alloy 6111 has been studied by means of differential The electrolytically polished condition served as a reference. Fatigue scanning calorimetry and transmission electron microscopy. It was tests were performed in rotating beam loading (R=-1) in air and in found that in contrast to the precipitation sequence in Al-Mg-Si al- 3.5% aqueous NaCl solution at frequencies of about 60 Hz. It was found that the response of the magnesium alloy to shot peening depended loys, which is usually GP zones—needle-like β”—rod-like β’—β platelets, the precipitation sequence in the 6111 alloy is believed to be: GP strongly on Almen intensity, i.e., pronounced lifetime improvements were observed only in a range of very low Almen intensity. Higher zones—needle-like β”—lath-like Q’—Q. Financial support from Ford Motor Company is gratefully acknowledged. intensities led to marked overpeening effects. In contrast, the aluminum alloy showed no loss in lifetime with increasing Almen intensity. 3:10 PM Since both alloys responded with a similar lifetime improvement to Effect of Different Natural Aging Times on the Precipitation increasing rolling forces in roller-burnishing (which generally leads to Behaviour of AA6111: Shahrzad Esmaeili1; Warren James Poole1; a smooth surface finish) it is argued that the shot peening-induced high David J. Lloyd2; 1University of British Columbia, Dept. of Metals and surface roughness and microcracks are the main reason for the marked Matls. Eng., 309-6350 Stores Rd., Vancouver, BC V6T1Z4 Canada; sensitivity of the magnesium alloy to Almen intensity in shot peen- 2Alcan International, Kingston Rsch. and Dev. Ctr., P.O. Box 8400, ing. Kingston, ON K7L5L9 Canada It has been shown that natural aging after solution treatment nega- 4:30 PM tively affects the subsequent artificial aging response for 6000 series Comparison of Microstructures between the As Cast and Rap- 1 1 2 aluminum alloys. In this work, the effect of different natural aging idly Solidified A 390 Alloy: E. G. Baburaj ; R. Fielding ; K. Prisbrey ; 3 3 1 1 times has been examined for the automotive alloy AA6111. The level J. Hill ; R. Oswald ; F. H. (Sam) Froes ; University of Idaho, Instit. for of natural aging time was varied from 0 to 4 months and was then Matls. and Adv. Processes, 321 Mines Bldg., Moscow, ID 83844-3026 2 followed by artificially aging at 180°C. The changes in microstructure USA; University of Idaho, Dept. of Metallu. and Mining Eng., Mos- 3 were characterized using tensile tests, electrical resistivity measure- cow, ID 83844-3024 USA; LA Aluminum Casting, W. 1905 Miles Ave., Hyden Lake, ID 83835 USA 30 The hyper eutectic Al-Si base alloy A 390 (Al-17.5Si-4.5Cu-0.5Fe- 0.1Mn-0.55Mg-0.1Zn) is a better alternative to the widely used A356 (Al-7Si-0.2Cu-0.2Fe-0.1Mn-0.3-Mg0.1Zn-0.2Ti) due to its superior Cast Shop Technology: Modeling Solidi- properties which include good liquid alloy fluidity, small solidification range, high strength and rigidity, good thermal conductivity, low ther- fication and Flow mal expansion coefficient and good resistance to abrasion, wear and Sponsored by: Light Metals Division, Aluminum Committee corrosion. However A390 finds limited use due to poor ductility of the Program Organizers: Paul Crepeau, General Motors cast structure which usually consists of a eutectic matrix with a distri- Corporation, GM Powertrain Group, Pontiac, MI 48340-2920 bution of blocky primary Si particles. Modification of the alloy, through addition of P, Na and Sr, is known to reduce the primary Si particle size USA; James N. O’Donnell, Commonwealth Aluminum and thereby improve the ductility. Application of rapid solidification Corporation, Department of Engineering, Louisville, KY processing of the alloy can further reduce the particle size of silicon. 40202-2823 USA The present paper is a comparison of the effects of trace elements and cooling rate on the microstructure of the alloy. Monday PM Room: Mississippi 4:50 PM March 13, 2000 Location: Opryland Convention Center PM MONDAY The Effect of Porosity on the Fatigue Properties in a Cast 319 1 1 1 Al Alloy: James M. Boileau ; John E. Allison ; Ford Motor Com- Session Chair: Yogesh Sahai, Ohio State University, Dept. pany, Scientific Rsch. Labs., MD 3182 SRL, P.O. Box 2053, Dearborn, MI 48121-2053 USA of Matls. Sci. and Eng., Columbus, OH 43210 USA As the automotive industry increases its use of cast aluminum components, the need for more detailed information relating the effect of 2:00 PM Opening Remarks casting practice on fatigue behavior also increases. One of the key factors influencing the fatigue of cast aluminum is porosity. There- 2:05 PM fore, a study characterizing the influence of solidification time on the 3-D Modeling of Fluid Flow and Heat Transfer during the DC microstructure and fatigue properties in a cast 319 Al alloy was con- Casting Process-Influence of Flow Modeling Approach: Gerd ducted. Multiple fatigue tests were conducted on a cast 319 Al alloy Ulrich Gruen1; Dag Mortensen2; Andreas Buchholz3; 1VAW Aluminium (T6 and T7 heat-treatments) at selected stress levels so that valid AG, Rsch. and Dev., Georg-von-Boeselager-Strasse 25, Bonn D-53117 statistical comparisons could be made. Extensive metallographic and Germany; 2Institute for Energy Technology, Process Simulation Dept., fractographic characterization was performed to understand the influ- P.O. Box 40, Kjeller N-2007 Norway; 3Hoogovens Research & Devel- ence of pore size and distribution on fatigue life. In general, opment, Computational Fluid Dynamics, P.O. Box 10000, IJmuiden microporosity was associated with all of the fatigue failures and was 1970 CA The Netherlands located at or near the specimen surface. Also, as solidification time The improvement of the DC casting of aluminum rolling and extru- increased, the average initiating pore diameter increased and the num- sion ingots is an ongoing process. Besides implementation of opti- ber of samples having multiple initiating sites tended to increase. Mul- mized mold systems and automated control of the main process pa- tiple initiating sites were observed in several samples and were ob- rameters casting temperature, casting speed, metal level, and water served to have an effect on the fatigue. Quantitative measurements of cooling, the optimization of liquid metal distribution systems is an microporosity found that conventional metallographic techniques sub- actual matter of research. Various numerical models of the coupled stantially underreport the maximum pore size present in the W319 fluid flow and heat transfer phenomena dominating the DC casting alloy. process have been developed and used for understanding the complex interactions between liquid transport and temperature evolution in the 5:10 PM solidifying ingot. Although they are based on the same set of equations 1 1 Age Softening of AA5182 Alloy: Jian Chen ; James G. Morris ; some differences exist concerning the implementation of the flow 1 University of Kentucky, Chem. and Matls. Eng. Dept., Anderson Hall phenomena. In order to evaluate the influence of the chosen fluid flow 177, Lexington, KY 40503 USA model (laminar, turbulent) on the resulting velocity and temperature The age softening phenomenon of AA5182 alloy was studied. The distribution, three different 3-dimensional implementations used in effect of different degrees of cold rolling, aging temperature, the aluminum industry (based on the software ALSIM, FIDAP, homogenisation temperature on the age softening behavior were mea- PHOENICS/CFX) are compared by means of a set of well defined sured. It was found that no observable changes in crystallographic reference cases. The resulting temperatures and flow patterns of the texture, grain size, particle size and distribution and even in dislocation three models are discussed in dependence of modified material proper- structure occur during the age softening process, but the electricity ties, boundary and geometrical conditions and implemented flow model resistivity decreases continuously. The age softening process is a ther- parameters. In addition, the results are qualitatively compared with mally activated and it accelerates with increasing aging temperature. temperature measurements in the liquid pool during an experimental The activation energy of the age softening process was measured. The trial program. mechanism to cause this phenomenon is discussed. 2:30 PM Effect of Mushy Zone Mechanical Properties on the Calculated Stresses and Deformations during the Casting of an Alumi- num Alloy Ingot: Alvaro Giron1; Men Glenn Chu1; Ho Yu1; 1Alcoa Inc., Alcoa Tech. Ctr., 100 Tech. Dr., Alcoa Center, PA 15069 USA An improved constitutive model which describes the mechanical behavior within the freezing range of an aluminum alloy has been used to estimate the stresses and deformations during the early stages of the DC casting process. Comparison is made with the stresses and deformations calculated with a similar constitutive model that extrapolates property data measured at lower temperatures. 2:55 PM Determination of Boundary Conditions Using Inverse Station- ary Methods: Jean Marie Drezet1; Gerd-Ulrich Gruen2; Marco Gremaud3; 1Laboratoire de Metallurgie Physique Calcom SA, Ecole Polytechnique Federale de Lausanne, MXG Ecublens, Lausanne CH- 1015 Switzerland; 2VAW Research and Development, VAW Aluminum 31 AG, P.O. Box 2468, Bonn D-53014 Germany; 3Calcom SA Parc allows for diffusional solute mixing in both the solid and liquid phases Scientifique, Ecole Polytechnique Federale, De Lausanne PSE, Lausanne during the primary phase and monovariant Al-Si eutectic stage of

MONDAY PM CH-1015 Switzerland freezing. This paper demonstrates the predicted influence of cooling The direct chill (DC) casting process is widely used in the aluminium rate on the proportions of primary phase, binary eutectic and ternary industry to produce rolling sheet ingots and extrusion billets. In both eutectic under non-equilibrium freezing conditions for a range of alloy processes, the metal is cooled down firstly by contact with the mould compositions. (primary cooling) until an air gap forms and reduces the heat transfer 4:40 PM to almost zero, and secondly by application of a water jet on the ingot Microstructure Prediction in A356 Alloy Castings: Qingyou surface (secondary cooling). In order to quantify the cooling condi- Han1; Srinath Viswanathan1; 1Oak Ridge National Laboratory, Metals tions undergone by an ingot during DC casting, temperatures were and Ceramics, Bldg. 4508, MS 6083, Oak Ridge, TN 37831 USA measured by thermocouples immersed in the liquid pool and then en- As part of a program to develop advanced tools for the design and trapped by the solid. In run conditions of casting, the thermal field is optimization of structural A356 aluminum alloy castings, models have stationary in a reference attached to the mould. Therefore, the mea- been developed and used for predicting phase fractions and microstruc- sured temperature histories were converted into temperature profiles tural length scales. The models predict phase evolution during solidifi- and used in the inverse method described by Rappaz et al. and adapted cation and the final length scales after solidification. These length to stationary temperature conditions. This allowed to deduce in a first scales are the primary dendrite size, secondary dendrite arm spacing, the temperature dependent thermal conductivity of the alloy, and to and cell spacing for the primary aluminum phase and the particle/rod determine in a second step the highly non uniform distribution of the size for the silicon phase. Mechanisms governing the growth of these thermal heat flux extracted at the lateral surface of the ingot and phases are considered in the models. The predictions are compared corresponding to the primary and secondary cooling. with independent measurements by other researchers and with data 3:20 PM from the literature. The results of the models are presented in the Modeling of Solidification of Al Alloys in a Laboratory Scale form of analytical equations for each of the length scales. The simple DC-Simulator: Xiaohong Yang1; 1University of Quebec at Chicou- form of the equations allow them to be used in the post processing step timi, Dept. of Appl. Sci., 555 Blvd. De l’Universite, Chicoutimi, Que- of commercial solidification codes for the prediction of microstruc- bec G7H2B1 Canada ture in shape castings. A mathematical model has been developed in order to study the 5:05 PM influence of natural convection on the solidification of aluminium Enthalpy Variations and Latent Heat Evolution during Solidi- alloys during direct-chill (DC) casting. The computer model simulates fication of Lead-Tin Alloys: Sergio Fabian Gueijman1; Alicia Esther heat transfer, fluid flow, solid transport and microstructure evolution Ares1; Carlos Enrique Schvezov1; 1University of Misiones, Faculty of during solidification in a laboratory scale DC-simulator using the vol- Sci., Azara 1552, Posadas, Misiones 3300 Argentina ume averaging method. It deals with both macroscopic and micro- In order to achieve improved predictions in a solidification process scopic aspects of solidification. Both equiaxed structure and columnar using mathematical modeling, it is necessary to couple the solidifica- structure, as well as the columnar-equiaxed transition, are incorpo- tion modeling with an accurate thermodynamic model. In the present rated in the model. The simulated results fitted well with the experi- report, several thermodynamics aspects related to solidification of mental data, and it was shown that natural convection has significant Lead-Tin alloys are considered. Such aspects are; the solidification effects on the temperature field. path, the solid fraction vs. temperature, and the enthalpy and the 3:45 PM Break latent heat evolution. A thermodynamic model including the above phenomena is developed and the values of the associated parameters 3:50 PM are calculated, particularly the enthalpy of the solid and liquid phases Microporosity Prediction in Aluminum Alloy Castings: Adrian of the alloys in the mushy zone, as a function of temperature and alloy S. Sabau1; Srinath Viswanathan1; 1Oak Ridge National Laboratory, concentration. From the calculated enthalpies, the latent heat re- Metals and Ceramics, Bldg. 4508, MS 6083, Oak Ridge, TN 37831 leased during solidification, which is a key input parameter in any USA solidification model, can be readily obtained. The total integrated heat As part of a program to develop models for the prediction of released for complete solidification of Lead-Tin alloys calculated with microporosity in cast lightweight automotive structural parts, a com- the present model are in good agreement. prehensive model that takes into account solidification, shrinkage- driven interdendritic fluid flow, hydrogen precipitation, and porosity evolution has been developed for the prediction of microporosity fraction. Experimentally determined values of liquid metal permeability in the mushy zone were used to calculate pressure distributions in solidifying castings. The pressure distribution in a solidifying casting, coupled with a microporosity criterion involving the local hydrogen concentration and the effect of surface tension, is used to predict microporosity distributions in aluminum alloy castings. The results are compared with experimentally measured microporosity distributions in A356 aluminum alloy test castings. 4:15 PM A 2D Cellular Automaton-Finite Difference (CAFD) Model of the Solidification of Aluminium-Rich Al-Cu-Si Alloys: David John Jarvis1; John Anthony Spittle1; Stephen Graham Brown1; 1Uni- versity of Wales, Matls. Eng. Dept., Singleton Park, Swansea, Wales SA28PP United Kingdom A 2D cellular automaton-finite difference (CAFD) model has been developed for simulating the solidification transformations in ternary aluminium-rich Al-Cu-Si alloys. A novel feature of the model is that initial primary phase solidification occurs in a dendritic fashion, either columnar or equiaxed. A combined curvature/surface energy anisotropy routine ensures that dendrite arm growth occurs orthogonally. The model overcomes many of the limitations of traditional 1D plate numerical models by allowing solidification and solute redistribution to occur within a naturally evolving microstructure. In addition, the model 32 study the influence of hydrogen on the cyclic plastic behaviour of such crystals, in comparison with pure crystals. This is of particular interest Cyclic Deformation and Fatigue of in two cases: when hydrogen enters the materials during the fatigue Materials; A Symposium in Honor of test (corrosion fatigue under cathodic charging) and when hydrogen- precharge has been made before cycling. It is known that hydrogen Professor Campbell Laird: Cyclic decrease the cross slip ability in fcc Ni crystals at room temperature. Deformation and Mechanism (I) However, the influence of cross slip on PSB formation and evolution is known to be quite important. Thus the influence of hydrogen on the Sponsored by: ASM International: Materials Science PSB formation and the corresponding cyclic plastic behaviour is Critical Technology Sector, Structural Materials Division, Jt. analysed on pure Ni single crystals in two experimental conditions:

Mechanical Behavior of Materials during corrosion fatigue in a 0.5N H2SO4 solution at applied cathodic Program Organizers: Zhirui Wang, University of Toronto, potential and during fatigue after hydrogen precharging. A particular Department of Metals and Materials Science, Toronto, attention is paid on the effect of hydrogen on cyclic softening. TEM analyses emphasize such influence. Mechanical consequences are then Ontario, Canada; Charles McMahon, University of Pennsyl- detailed. vania, Department of Materials Science and Engineering, PM MONDAY Philadelphia, PA 19104 USA; Pedro D. Peralta, Arizona State 2:50 PM Mean Stress Effect on Cyclic Plastic Deformation of Industrial University, Department of Mechanical and Aerospace Pure Iron: Hai Ni1; Zhirui Wang1; 1University of Toronto, Dept. of Engineering, Tempe, AZ 85287-6106 USA; J. K. Shang, Metallu. and Matls. Sci., Toronto, Ontario M5S3E4 Canada University of Illinois, Department of Materials Science and It has been reported recently that sagging behavior in spring steels Engineering, Urbana, IL 61801 USA is a direct result of asymmetrical cyclic loading. Although previous work showed that cyclic creep and cyclic softening are the two main causes for sagging in mechanical springs, the mechanisms of sagging Monday PM Room: Canal A are still not well understood. In order to characterize sag resistance March 13, 2000 Location: Opryland Convention Center more precisely and to understand sagging mechanisms, both symmetrical and asymmetrical cyclic loading tests, rather than stress relaxation Session Chairs: P. Lukas, Institute of Physics of Materials, and the Bauschinger effect test, were carried out systematically on Brno Czech Republic; Z. Wang, University of Toronto, model material: industrial pure iron. It was chosen based upon the need to simplify the complicated microstructural effect on dislocation mo- Dept. of Met. & Matls. Sci., Toronto, Ontario, Canada tion in suspension spring steels. Mechanical results were explored in detail, and slip band evolution and dislocation structures were also 2:00 PM studied using an in situ optical microscope and transmission electron Effect of Loading History on Cyclic Stress-Strain Response microscopy (TEM), respectively, to gain additional information on and Cyclic Creep: L. Kunz1; P. Lukas1; B. Weiss2; D. Melisova2; the cyclic plastic deformation process. In addition, the effect of the 1Institute of Physics of Materials, ASCR, Brno Czech Republic; 2Uni- pre-strains on cyclic softening and cyclic creep was evaluated from the versity of Vienna, Instit. of Matl. Physics, Vienna, Austria energy point of view. Based upon the present study, the following Cyclic plasticity of metals depends on loading history. The cyclic conclusions have been drawn: first, in contrast with tensile slip bands, hardening/softening, steady-state behaviour, cyclic strain localisation, fatigue slip bands showed much less multi-slip even at high cyclic peak fatigue limit and fatigue lifetime are influenced by preceding deforma- stress levels and a large amount of cumulative cyclic plastic strain; tion, both cyclic and monotonic. A cyclic mechanical equation of second, mean stress was found to have a significant effect on the state, relating the saturation stress-amplitude with the saturation-strain magnitude of cumulate cyclic creep strain; third, proof was obtained amplitude, is generally not applicable. The changes of microstructure demonstrating that dislocation cell size decreases with increasing cy- due both to the monotonic and cyclic strain are considered to be the clic stress amplitude; forth, compressive cyclic creep was found in all main reason for these effects. The aim of this contribution is to pre-strained samples due to Bauschinger effect and such an effect was summarise the effect of the loading history on the cyclic stress-strain found to disappear completely in only 25-30 cycles and, therefore, response of Cu and Ni and to contribute to the completion of the this is a strong proof that sag deformation is mainly due to cyclic creep partial understanding of the influence of the loading history repre- and cyclic deformation; finally, both increasing pre-strain level and sented by different ramp loading and pre-strain on the cyclic plasticity decreasing cyclic peak stress resulted in less overall recoverable en- and cyclic creep. It will be shown that the cyclic stress-strain response ergy, and this stored energy is believed to promote the material to (cyclic stress-strain curves), dislocation microstructure and the strain enter its stable stage of dislocation substructure more earlier, even localisation both in single and polycrystals are strongly influenced by though it may be released very slowly late in the deformation if the the start-up procedure (ramp loading) and pre-strain. Both the ramp load is not symmetrical. loading (its length and the details of the load increase sequence) and 3:15 PM the pre-strain in the first loading cycle (implicitly introduced in tests Analytical Solutions at 180° Twist Boundaries in Cubic Crys- with the mean stress) affects the cyclic creep behaviour, plastic strain tals: Peter Neumann1; 1Max-Planck Institute for Iron Research, amplitude and the number of cycles to fracture elapsed at full stress Max-Planck-Str. 1, Duesseldorf D-40237 Germany amplitude. The saturated plastic strain amplitude has been found to be Grain boundaries are efficient stress raisers in elastically anisotropic related to the cyclic creep strain in saturation. This indicates that the materials. Because of the complexity of the underlying equations, the description of the cyclic plasticity entirely in terms of the plastic elastic incompatibility stresses are usually determined numerically. In strain amplitude is insufficient and additional data on the cyclic creep a recent paper the transformation behavior of compliances and elastic (monotonic strain) are inevitable. constants in anisotropic cubic crystals was treated analytically and the 2:25 PM equations of compatibility and stress equilibrium were solved analyti- Cyclic Plastic Deformation Behaviour of Ni Single Crystals cally for the most simple case of a coherent twin boundary. This ° Oriented for Single Slip as a Function of Hydrogen Content: treatment is extended in the present paper to the whole class of 180 Thierry Magnin1; C. Bosch1; K. Wolski1; 1Ecole des Mines de Saint- twist boundaries. The point is stressed that no additional shear stresses Etienne, Ctr. SMS URA CNRS 1884, 158 Cours Fauriel, St Etienne, on the boundary are produced by the piecewise constant incompatibil- Cedex02 42023 France ity stresses. The observed slip activity and crack initiation at the Ni single crystals oriented for single slip exhibit as Cu crystals a well surface and on planes parallel to the twin boundary is due to an addi- defined stress-strain curve at room temperature corresponding to PSB tional logarithmic stress singularity at the intersecting line between formation in a given plastic strain range. The aim of this paper is to the twin boundary and the specimen surface. The strength and direc- 33 tion of these singular stresses is determined by the tractions of the incompatibility stresses on the surface. They are given analytically as 1The Ohio State University, Dept. of Matls. Sci. and Eng., Columbus, well. OH 43210 USA; 2The Ohio State University, Dept. of Food, Agri. Biolog. and Aero. Eng., Columbus, OH 43210 USA; 3Princeton Uni- MONDAY PM 3:40 PM Break versity, Dept. of Mech. and Aeros. Eng., Princeton Matls. Instit., 4:05 PM Princeton, NJ 08544 USA Characterization of Dislocation Glide Kinetics during Cyclic This paper presents the results of an experimental study of short Deformation by Strain Rate Change Tests: George C. Kaschner1; and long fatigue crack growth in an a/b titanium alloy, Ti-6Al-4V. Jeffery C. Gibeling2; 1Los Alamos National Laboratory, MST-8, Los Differences between long fatigue crack growth rates at positive stress Alamos, NM 87545 USA; 2University of California, Dept. of Chem. ratios are shown to be due largely to the effects of crack closure. Eng. and Matls., Davis, CA 95616 USA Coarse Widmanstätten microstructures are also shown to exhibit higher A new experimental technique incorporating strain rate changes intrinsic fatigue crack growth resistance than fine Widmanstätten or during cyclic deformation has been developed using plastic strain as near-equiaxed a/b microstructures in the long crack regime. The im- the control variable. This technique was used to study the kinetics of proved fatigue crack growth resistance is associated with higher levels dislocation interactions by evaluating the operational activation area of roughness-induced crack closure and crack deflection. The fatigue and true stress as a function of cumulative plastic strain. In order to fracture modes are summarized in fatigue mechanism maps before demonstrate the utility of this approach, it has been applied to three presenting multiparameter and mechanism-based fracture mechanics FCC metals: polycrystalline pure copper, 7075-T6 aluminum, and 304 models for the prediction of fatigue crack growth. stainless steel. These materials represent produce three distinct categories: pure FCC metals, precipitation-strengthened metals, and solution-strengthened metals. Plastic strain rate change tests were performed at plastic strain amplitudes between 0.2% and 0.6% from a base Dislocations and Microscale Plasticity rate of 10-3s-1 at room temperature. Initial values of the operational activation areas of copper evolved from approximately 5000b2 to Modeling: Experimental Characteriza- 700b2 during cyclic loading to saturation. These values indicate a tran- tion of Dislocation Structures sition from forest dislocation cutting to cross-slip as the rate-controlling mechanism. Tests performed at saturation revealed a linear de- Sponsored by: ASM International: Materials Science pendence of activation area on plastic strain amplitude. The back Critical Technology Sector, Materials Processing and stress measured at saturation by extrapolating the activation area data Manufacturing Division, Structural Materials Division, Jt. compares favorably with the value determined from a Bauschinger Mechanical Behavior of Materials, Jt. Computational analysis. The extrapolation method is an objective method of deter- Materials Science & Engineering mining back stress and is especially suited for materials with asymmetrical hysteresis loops. The method is sensitive to the nuances of Program Organizers: Elizabeth Holm, Sandia National dislocation interactions of the various classes of materials tested; the Laboratories, Albuquerque, NM 87185-1411 USA; Diana characteristic responses of copper, 7075-T6 aluminum, and 304 stain- Farkas, Virginia Polytechnic Institute and State University, less steel are distinct. Values of activation area correlate with the Department of Materials Science and Engineering, dominant rate controlling dislocation interaction mechanisms. In cop- Blacksburg, VA 24061 USA; Jeffrey Rickman, Lehigh per, these values correspond to a transition from cutting of forest dislocations to dislocation cross-slip. The results for 7075-T6 alumi- University, Department of Materials Science and Engineer- num reveal that deformation is controlled by interactions with ther- ing, Bethlehem, PA 18105-3195 USA; David J. Srolovitz, mal obstacles in the form of GP zones and precipitates. Finally, this University of Michigan, Department of Materials Science approach shows that rate-sensitive obstacles in the form of solutes and Engineering, Ann Arbor, MI 48109 USA; Vaclav Vitek, control the cyclic deformation of type 304 stainless steel. This paper University of Pennsylvania, Department of Materials is based on work support by the National Science Foundation under Grant No. DMR-9208549. Science and Engineering, Philadelphia, PA 19104 USA 4:30 PM Cyclic Plasticity of Nickel at Low Plastic Strain Amplitude: Y. Monday PM Room: Lincoln A Jia1; D. J. Morrison1; J. C. Moosbrugger1; 1Clarkson University, Dept. March 13, 2000 Location: Opryland Convention Center of Mech. and Aeronautical Eng., Potsdam, NY 13699-5725 USA The cyclic plasticity of polycrystalline nickel was studied by ac- Session Chair: Diana Farkas, Virginia Polytechnic Institute, complishing room temperature fully-reversed fatigue experiments at a Matls. Sci. & Eng., Blacksburg, VA 24061-0237 USA constant plastic strain amplitude of 1.0x10-4 on nickel with a grain size of 290 µm. The cyclic plasticity behavior within a hysteresis loop 2 2 was analyzed by measuring the curvature of the loop, d σΓ/dεΓ , where 2:00 PM Invited

σΓ and εΓ are, respectively, the stress and total strain measured from Observation and Modeling of Grain Boundary Dislocation the reversal point. In the classical Masing model of kinematic harden- Structure and Behavior: Douglas L. Medlin1; 1Sandia National ing, the curvature can be related to the frequency distribution of mate- Laboratories, Thin Film and Interface Sci. Dept., Mail Stop 9161, rial volume element yield stresses. The results indicate that at low 7011 E. Ave., Livermore, CA 94551 USA values of cumulative plastic strain, the cyclic plasticity within a loop Incorporating the localized effects of interfaces on materials prop- approximates classical Masing kinematic hardening memory. How- erties is a significant challenge for large-scale materials simulations. ever, at higher values of cumulative plastic strain, significant devia- Critical to improving such models is developing an improved under- tions from Masing memory are observed; and the behavior tends to standing of the behavior of dislocations incorporated at grain bound- reflect kinematic type III hardening as defined by Asaro[1]. The results aries. In this presentation, we discuss atomistic and continuum models will be discussed in terms of fundamental dislocation structures that are for interfacial dislocations in relation to experimental observations produced during low plastic strain amplitude cycling of pure fcc metals made by transmission electron microscopy, focussing initially on in- and the relationships between single crystal and polycrystal deforma- terfacial dislocations in the FCC Σ=3 system. Though a simple geom- tion behavior. This research was supported by the National Science etry, the interfacial dislocations present in this system exhibit a rich Foundation under grant CMS 963407. [1]Asaro, R.J., 1975, Acta Metall., and complex set of behavior. From an analysis of these defects, we 23, 1255-1265. provide insight into the larger scale coupling of dislocation motion, by both glide and climb processes, with grain boundary behavior. Finally, 4:55 PM we discuss means of extending these results to boundaries of increasing Micromechanisms of Fatigue Crack Growth in an a/b Titanium crystallographic complexity. This work is supported by the U.S. DOE Alloy: V. Sinha1; S. Shademan1; A. B.O. Soboyejo2; W. O. Soboyejo3; under contract DE-AC04-94AL85000, and in part by the OBES-DMS. 34 2:40 PM suggests that yielding of the samples is not limited by the mobility of Micro- and Macro-Scale Subdivision of a Bicrystal Based on dislocations. Instead the transition may be controlled by the nucle- Experiment and Plasticity: A. Godfrey1; V. Prantil1; D. E. Boyce2; ation of a sufficient density of dislocations within the material. This D. A. Hughes1; H. R. Wenk3; P. Dawson2; 1Sandia National Laboratory, idea is further supported by experiments that were conducted at tem- MS 9403, P.O. Box 969, Livermore, CA 94551-0969 USA; 2Cornell peratures below 730°C in which samples were preloaded within the University, Sibley School of Mech. and Aerospace Eng., Ithica, NY linearly elastic regime and then immediately retested. This preloading 14853 USA; 3University of California, Dept. of Geology, Berkeley, CA effectively enhanced the yield behavior of the samples with the degree 94720 USA of plasticity displayed by the samples a function of the magnitude of Bicrystals of high purity aluminum have been deformed at room the preload. At the highest preloads complete yielding occurred, indi- temperature to strains of 15-60%. The shape change and local crystal cating that the BDT temperature had been lowered. orientations were investigated by optical and scanning electron mi- 4:00 PM croscopy to characterize the macroscopic deformation pattern, thereby Analysis of Anomalous Slip in Ta Single Crystals Using Opti- providing data at a length scale suitable for comparison with crystal cal Atomic Force, Orientation Imaging and Transmission Elec- plasticity model predictions. Preliminary calculations corroborate the tron Microscopies: Geoffrey H. Campbell1; James S. Stölken1; Mehdi shape changes away from the boundary, confirming that the crystal 1 1 1 1

Balooch ; Wayne E. King ; Adam J. Schwartz ; Livermore National PM MONDAY plasticity models resolve the average slip system activity reasonably Laboratory, Chem. and Matls. Sci. Directorate, P.O. Box 808, L-356, well. However heterogeneous dislocation microstructures are observed 7000 E. Ave., Livermore, CA 94551 USA in the transmission electron microscope (TEM). These microstruc- High purity Ta single crystals oriented for single slip were deformed tures have been extensively investigated in the TEM in order to deter- in compression at 300K and 77K. The sample deformed at 300K mine the pattern of microscale slip activity, using both Burger’s vector exhibited wavy glide whereas the sample deformed at 77K exhibited analysis and Frank formula analyses of the observed rotation bound- anomalous slip. Sharp load drops were recorded in the stress-strain aries. The implications of the observed microscale slip pattern for curve of the sample tested at 77K. Previous work attributes such crystal plasticity models are then discussed. Part of this work was unloading events to either the formation of large deformation twins or supported by the Office of Basic Energy Sciences, U.S. DOE, under to the anomalous slip process itself. Orientation imaging microscopy contract No: DE-AC04-94AL85000. was applied to probe lattice rotations occurring as a result of deforma- 3:00 PM tion in an effort to detect the presence of large deformation twins, Studies of Microscale Plasticity in Bulk Samples Using ECCI: none were found. Optical and atomic force microscopies were applied Benjamin Andrew Simkin1; Boon Chai Ng1; Martin A. Crimp1; Thomas to map the slip traces appearing on the sample surface. Atomic force R. Bieler1; 1Michigan State University, Dept. of Matls. Sci. and Mech., microscopy revealed that the fine structure within the rather coarse 3536 Eng., East Lansing, MI 48824 USA anomalous slip bands is comprised of atomistic scale slip lines orga- Electron channeling contrast imaging (ECCI) is a scanning electron nized into packets. These slip packets appear to account for the “fine microscopy technique that allows the direct imaging of dislocations slip traces” often observed within anomalous slip bands. Transmission and other deformation structures in the near-surface region of bulk electron microscopy was used to characterize the difference in disloca- crystals. ECCI forms contrast from regions of crystal distortion and tion structures between the specimens deformed at 300K and 77K. rotation, such as occur near dislocation cores, twins, and grain bound- The fine scale dislocation structure within the anomalous slip bands is aries. Although the contrast obtained using ECCI is similar to that compared to the corresponding slip trace structure examined with found using diffraction contrast transmission electron microscopy, as atomic force microscopy. This work is performed under the auspices ECCI uses bulk samples, it has the advantages that dislocations can be of U.S. Department of Energy and Lawrence Livermore National Labo- imaged under well defined stress states and large areas can be surveyed. ratory under contract No. W-7405-Eng-48. Direct images of the dislocation structures associated with crack propa- 4:20 PM gation and arrest has been assessed by imaging at crack tips and along Flow Stress Behavior of Polycrystalline OFHC Copper: John crack paths in single crystal NiAl. Crack deflections and arrest are E. Flinn1; David P. Field2; Thomas M. Lilo3; Gary E. Korth3; Jenya found to be directly associated with variations in dislocation genera- Macheret4; 1University of Idaho, 3450 S. 35 W., Idaho Falls, ID 83402 tion in the crack tip zone. Deformation transfer across grain bound- USA; 2TSL Inc., 392 E. 12300 S., Ste. H, Draper, UT 84020 USA; aries has been studied in relation to sample loading and macroscopic 3Idaho National Engineering and Environmental Laboratory, P.O. Box stress states in polycrystalline $\gamma$+$\alpha_{2}$ Ti-Al alloys. 1625, MSC2218, Idaho Falls, ID 83415-2218 USA; 4U.S. Department Strain transfer across grain boundaries is often found to occur by pri- of Energy, Idaho Operations Office, 850 Energy Dr., MS-1225, Idaho mary twinning inducing dislocation emission in adjacent grains from Falls, ID 83401 USA the twin/grain boundary intersection. Portions of this work were sup- The flow stress behavior of OFHC polycrystalline copper was evalu- ported in part by the National Science Foundation (DMR\#9302040), ated from tensile specimens derived from cold roll and equal-channel Office of Naval Research (N00014-94-1-204), and the MSU Research angular extrusion processing. Prior to testing at room temperature, Excellence Fund. the specimens were annealed to provide grain sizes from 0.002 to 0.05 3:20 PM Break mm. The true stress-true strain behavior exhibit a parabolic pattern that correlates with four stages of hardening. In association with an 3:40 PM increase in strain we observe: 1) dislocation source activation at the Temperature-Dependent Onset of Yielding in Dislocation-Free onset of plastic flow at annealing twin boundaries; 2) primary slip; 3) Silicon: Evidence of a Brittle-to-Ductile Transition: Robert H. cross slip and forest hardening that is tied to stacking fault behavior; Folk1; David P. Pope1; M. Khantha1; Vaclav Vitek1; 1University of and 4) dynamic recovery. The tensile properties and analyses are Pennsylvania, Dept. of Matls. Sci., LRSM, 3231 Walnut St., Philadel- accompanied by orientation imaging and transmission electron mi- phia, PA 19104 USA croscopy examinations and measurements. An investigation of the brittle-to-ductile transition (BDT) in silicon has been conducted. Photolithography has been used to produce 4:40 PM silicon test specimens from semiconductor grade silicon wafers that Effect of Temperature and Alloy Composition on Deformability 1 were essentially defect free. No pre-cracks or additional dislocation of HfV2+Ta C15 Laves Phase Alloy: Won Yong Kim ; David E. sources were introduced into the samples. High temperature three- Luzzi1; David P. Pope1; 1University of Pennsylvania, Matls. Sci. and point bending tests of the samples reveals a well defined transition Eng., 3231 Walnut St., Philadelphia, PA 19104 USA from brittle fracture of the specimens to complete yielding near 730°C The occurrence of twinning in Laves phase alloys is sensitive to at a crosshead displacement rate of 0.01 cm/min. Limited plasticity is alloy composition and deformation conditions such as strain rate and observed prior to the transition but is insufficient to prevent crack temperature. However, it remains unclear based on the existing work ° ° propagation. In addition, between 735 C and 745 C there exists a in the HfV2+Nb system whether the twinning is solely stress-driven or temperature interval in which only limited plasticity is observed. This whether there exists a critical temperature for twinning. Results in the 35 HfV2 system are somewhat ambiguous due to a fairly complex phase equilibria and the predicted presence of a low temperature phase insta- Materials Research through grant DMR-9812211 with Dartmouth

bility. We have recently found that alloying HfV2 with Ta yields more College. extensive room temperature ductility by twinning in ternary Laves MONDAY PM 2:20 PM phase alloys that are more easily studied. In the present paper, Ta is Processing and Mechanical Properties of Mo-Si-B Alloys Con- again chosen as the ternary alloying element in HfV . HfV +Ta Laves 2 2 taining High Volume Fractions of Mo Si and Mo SiB : Joachim phase based alloys with various compositions are produced by arc- 3 5 2 H. Schneibel1; Hua-Tay Lin1; 1Oak Ridge National Laboratory, Metals melting and float-zone-melting. X-ray diffraction is used to analyze and Ceramics Div., P.O. Box 2008, Oak Ridge, TN 37831-6115 USA the crystal structures and lattice parameters for each sample investi- Mo-Si-B alloys have melting points on the order of 2000°C. Their gated. Compression tests are conducted at temperatures down to near optimum composition involves a trade-off between processing, frac- liquid helium temperatures using a specially designed testing apparatus. ture toughness, and oxidation resistance. Mo-12Si-8.5B (at. %) can be The effect of temperature and composition on mechanical properties fabricated by casting and contains approximately 30 vol.% Mo Si, 30 is investigated to gain a better understanding of the mechanisms of 3 vol.% Mo SiB , and 40 vol.% α-Mo. The α-Mo occurs in the form of twinning. Alloy microstructures are characterized using conventional 5 2 toughening inclusions. At room temperature this alloy exhibits a 3- and high-resolution TEM. Based on the obtained results, the deforma- point flexure strength of 500 MPa and a fracture toughness on the tion mechanisms will be discussed with particular attention given to order of 10 MPa m1/2. Its tensile creep properties, determined at 1200°C the nucleation of twinning in the C15 cubic Laves phase. in argon, will be discussed. Mo-Si-B alloys with a continuous α-Mo 5:00 PM matrix were fabricated by powder-metallurgical techniques and their Strengthening Effects from Nitrogen Content and Grain Size mechanical properties and oxidation resistance will be compared to on the Flow Stress Behavior of Type 316 SS: Nikki Y. Pearce1; the corresponding properties for cast alloys. This research was spon- John E. Flinn2; 1Bechtel-Bettis Inc., Naval Reactors Facility, P.O. Box sored by the Fossil Energy Advanced Research and Technology Devel- 2068, Idaho Falls, ID 83403-2068 USA; 2University of Idaho, 3450 S. opment (AR&TD) Materials Program, U.S. Department of Energy, 35 W., Idaho Falls, ID 83402 USA under contract DE-AC05-96OR22464 with Lockheed Martin Energy The influence of grain size and nitrogen content on the tensile Research Corporation. behavior of Type 316 SS were evaluated. The focus of the analysis was 2:40 PM on the flow stress behavior in terms of parabolic hardening with true Phase Formation and Interdiffusion in Silicides and Aluminides strain. The results show a bilinear pattern, defined as parabolic stages of Mo With and Without Re Additions: Edward J. Ciecko1; Mysore II)p and III)p with increasing square-root of strain. The effects from A. Dayananda1; 1Purdue University, School of Matls. Eng., 1289 MSEE grain size and nitrogen content (in solid solution) are primarily associ- Bldg., West Lafayette, IN 47907 USA ated with the onset of plastic flow with very little influence on strain Diffusion structures developed by interdiffusion between disks of hardening. Stage II)p is associated with primary and secondary slip and Mo-aluminides in contact with disks of Mo, Si and Mo-silicides with Stage III)p with cross slip related dislocation forest hardening. and without additions of Re are investigated at selected temperatures between 700-1200°C. Phase formation and the effects of Al and Re on the interdiffusion of the components in the silicides of Mo will be discussed. Diffusion studies include an examination of the structures General Abstracts: Intermetallics I involving binary and ternary aluminides and silicides of the system Sponsored by: TMS Mo-Si-Re-Al. Diffusion structures will be described with the aid of Program Organizers: Mark E. Schlesinger, University of diffusion paths. Interdiffusion coefficients for the silicides and Missouri, Department of Metallurgical Engineering, Rolla, aluminides observed in the diffusion structures will also be presented. MO 65409-0001 USA; Alton T. Tabereaux, Reynolds Metals 3:00 PM Break Company, Smelter Technology Laboratory, Muscle Shoals, 3:20 PM + 1 AL 35661-1258 USA; Dan J. Thoma, Los Alamos National Composition and Mechanical Properties of Mo3Si: Isai Rosales ; Laboratory, Materials Science and Technology, Los Alamos, Joachim H. Schneibel1; 1Oak Ridge National Laboratory, Metals and NM 87545-0001 USA; Patrice E.A. Turchi, Lawrence Ceramics, P.O. Box 2008, Oak Ridge, TN 37831-6115 USA The A15 phase Mo3Si is an important constituent of a new class of Livermore National Laboratory, Materials Science and silicides based on Mo-Si-B (D. M. Berczik, U.S. Patent No. 5,595,616, Technology Division, Livermore, CA 94551 USA 1997; C. A. Nunes, R. Sakidja, and J. H. Perepezko, in “Structural Intermetallics 1997,” TMS). In this research we will show that, contrary to published results, single-phase Mo Si is slightly off-stoichio- Monday PM Room: Bayou E 3 March 13, 2000 Location: Opryland Convention Center metric. Its room temperature fracture toughness is on the order of 3.5 MPa m1/2. When the deformation rate is high (10-3 s-1), compressive deformation at 1400°C in argon often results in fracture associated Session Chair: John J. Stephens, Sandia National Labora- with a decrease in load. At low deformation rates (10-5 s-1) and 1400°C, tories, Albuquerque, NM 87185-0367 USA fairly constant loads are reached after a few percent deformation. Partial substitution of Mo by Cr increases the high temperature

strength. The high temperature strength of Mo3Si will be compared to 2:00 PM that of other silicides and A15 phases. This research was sponsored by 1 On the Yield Strength Anomaly in CoTi and CoHf: Ian Baker ; the Division of Materials Sciences, U.S. Department of Energy under 1 1 1 M. Wittmann ; P. Bove ; Dartmouth College, Thayer School of Eng., contract number DE-AC05-96OR22464 with Lockheed Martin En- 8000 Cummings Hall, Hanover, NH 03755 USA ergy Research Corporation. I. Rosales acknowledges partial support Mechanical tests have been performed on CoTi and CoHf alloys in from DGEP-FQ, Universidad Nacional Autonoma de Mexico. order to determine whether the George-Baker vacancy-hardening model (Phil. Mag., 77 (1998) 737), which has been developed for FeAl, is 3:40 PM applicable to the yield strength anomaly observed in these B2 com- Influence of Aging Treatment on the Microstructure and Hard- 1 1 pounds. Compression tests at elevated temperature reveal shifts in ness of a Cr-Cr2Ta Composite: Peter K. Liaw ; Yuehui He ; C. R. both the magnitude and temperature of the yield stress peak with Brooks1; C. T. Liu2; 1The University of Tennessee, Matls. Sci. and Eng. changes in strain rate which are consistent with the model. However, Dept., Knoxville, TN 37996-2200 USA; 2Oak Ridge National Labora- quenching experiments, suggest that the vacancy concentrations at tory, Metals and Ceramics Div., Oak Ridge, TN 37831-6115 USA elevated temperature are much lower in CoTi and CoHf than in FeAl, A Cr-Cr2Ta composite, as a new candidate of ultra-high temperature and possibly too low for the vacancy hardening to be applicable. This materials, is being studied. The excellent mechanical properties and work was funded by the National Science Foundation, Division of good oxidation resistance of the composite at temperatures above 36 1000°C are provided by a solid-solution Cr(Ta) matrix reinforced with

Cr2Ta laves-phase plates. In this study, the effects of the as-cast process and aging treatment on the microstructure and hardness of a Cr- General Non-Ferrous Pyrometallurgy: 9.8 at.%Ta composite were examined. The hardness of the composite Thermochemical Modeling and Physi- in the as-cast condition at room temperature decreased with increasing the aging temperature from 1000°C to 1300°C, which was due to the cal Properties reduction of the solid-solution extent of the Cr(Ta) matrix. The mor- Sponsored by: Extraction & Processing Division, Pyromet- phology and formation mechanism of the microstructures of the com- allurgy Committee posite in as-cast and aging-treatment states were explored. The orien- Program Organizers: Robert L. Stephens, Cominco tation relationships between the Cr2Ta phase and Cr(Ta) matrix were analyzed using transmission electron microscopy (TEM). This re- Research, Trail, British Columbia V1R 4S4 Canada; Pekka search is sponsored by the Fossil Energy Advanced Research and Tech- Taskinen, Outokumpu Research Oy, Pori FIN-28101 Finland nology Development (AR & TD) Materials Program under subcon- tract 11X-SP173V to the University of Tennessee with Dr. R. R. Monday PM Room: Bayou B Judkins as the contract monitor.

March 13, 2000 Location: Opryland Convention Center PM MONDAY 4:00 PM Effect of Temperature and Alloy Composition on Deformability 1 Session Chair: Pekka A. Taskinen, Outokumpu Research of HfV2+Ta C15 Laves Phase Alloy: Won Yong Kim ; David E. Luzzi1; David P. Pope1; 1University of Pennsylvania, Matls. Sci. and Oy, Pori FIN-28101 Finland Eng., 3231 Walnut St., Philadelphia, PA 19104 USA The occurrence of twinning in Laves phase alloys is sensitive to 2:00 PM alloy composition and deformation conditions such as strain rate and Heat and Material Balance Model of the Kokkola Zinc Roaster temperature. However, it remains unclear based on the existing work Based on the HSC Chemistry 4.0 Software: Antti Roine1; Jens in the HfV2+Nb system whether the twinning is solely stress-driven or Nyberg2; 1Outokumpu Research Oy, P.O. Box 60, Kuparitie 5, Pori whether there exists a critical temperature for twinning. Results in the 28101 Finland; 2Outokumpu Zinc Oy, P.O. Box 26, Kokkola 67101 HfV2 system are somewhat ambiguous due to a fairly complex phase Finland equilibria and the predicted presence of a low temperature phase insta- Sulfidic zinc concentrates are usually roasted in a fluidized bed fur- bility. We have recently found that alloying HfV2with Ta yields more nace into sulfur-free oxide form. Metallic zinc is produced from this extensive room temperature ductility by twinning in ternary Laves oxidic calcine using hydrometallurgical leaching, solution purification, phase alloys that are more easily studied. In the present paper, Ta is and electrowinning stages. The roasting step is needed because zinc again chosen as the ternary alloying element in HfV2. oxides are easier to dissolve than zinc sulfides using traditional leach- 4:20 PM ing methods. The Kokkola Zinc Smelter uses various types of zinc Room Temperature Deformation of Cr-Based Laves Phase Al- concentrates and secondary materials as the feed mixture. Because the loys: Won Yong Kim1; David E. Luzzi1; 1University of Pennsylvania, composition and particle size distribution of the feed mixture varies Matls. Sci. and Eng., 3231 Walnut St., Philadelphia, PA 19104 USA even on a daily basis, it is difficult to find the optimum process parameters for the process. Certain conditions may even cause difficult Cr-based Laves phase alloys with AB2 stoichiometry are promising material for high temperature structural applications due to their high accretion problems or increase the amount of calcine in the process melting temperatures, low density and potential resistance to corro- gas stream to an unacceptable level. A thermochemical heat and mate- sion and oxidation. Binary Laves phase alloys however, are extremely rial balance model was developed in order to estimate the effects of brittle at room temperature due to their complex crystal structure. different process parameters (temperature, process air coefficient, Ternary alloying has been shown to yield room temperature concentrate feed, oxygen enrichment, water feed, etc) on the heat balance, roasting temperature, and calcine composition. This model deformability by twinning in HfV2 with Nb or Ta. In the present study, refractory metals such as Hf, Ti, Ta and Nb are used as ternary alloying was constructed using the heat balance model of the HSC Chemistry elements in various Cr-based Laves phases through consideration of 4.0 software. The prevailing chemical compounds in the concentrate chemistry, atomic size and electron-atom ratio. Laves phase alloys and calcine were verified with the mineralogical analyses and equilib- with a wide range of compositions are produced by arc-melting. Crys- rium calculations. The roasting process seems to operate near the tal structure, microstructure and lattice parameter analyses are carried chemical equilibrium conditions, if the behaviour of the main compo- out using optical microscopy and x-ray diffraction. We find that room nents are considered. This paper describes briefly the basic principles temperature ductility is more common than currently understood with of the calculation model and outlines the results with several diagrams and discussion. The calculated results were in reasonable agreement extensive room temperature ductility possible in ZrCr2- and NbCr2- based cubic Laves phase alloys after ternary alloying. with the recent process air oxygen enrichment and water feed test campaigns carried out at Kokkola in 1999. 2:25 PM Evaluation of New Process Parameters and Operating Condi- tions in Non-Ferrous Pyrometallurgy Through Thermochemi- cal Modeling: Florian Kongoli1; Ian McBow1; 1Flogen Technologies, P.O. Box 49529, CP Du-Musee, Montreal, Quebec H3T2A5 Canada New operating conditions and process parameters are often necessary in today’s industrial practice of non-ferrous smelting and converting in order to accommodate various new chemical compositions of mineral charges and environmental requirements or to conceive new and more efficient industrial technologies. An effective way to evaluate and predict these important parameters and conditions is thermochemical modeling, which decreases considerably the cost of pure experimental evaluation. This work presents thermochemical modeling of various phases in non-ferrous smelting and converting and their effective use in the evaluation of several factors such as the liquidus temperatures of slag, matte/slag/metal distributions, activities of crucial components etc. Several practical easy-to-use diagrams are

37 presented along with examples of cost decrease. Future developments The most common method for decreasing the copper content of are also discussed. slags from autogenous smelting of copper sulfide concentrates is treat-

MONDAY PM ment of molten slag in an electric furnace, among other things, by 2:50 PM adding solid reducing and sulfiding agent, i.e., pyrite. One of the draw- The Correlation of Thermodynamic Properties of Multicompo- backs of this technique is production of final slag with a copper con- nent Liquid Alloy Systems: Dajian Wang1; Tae-Kyu Kim1; 1Univer- tent of about 0,5%. An innovative method was tested based on treat- sity of British Columbia, Dept. of Metals and Matls. Eng., AMPEL ment of molten slag from autogenous smelting process by a gaseous 2355 E. Mall, Vancouver, BC V6T1Z4 Canada mixture of sulfur dioxide and methane at a ratio of CH :SO =1:(3,0- To obtain the thermodynamic properties of a multicomponent liq- 4 2 4,7) in the presence of oxygen. Cleaning of slag to remove copper was uid alloy system over the whole range of concentration at an arbitrary carried out at a pilot plant in the second zone of the furnace where slag temperature, the free volume cell theory has been applied to derive was maintained within a range of 1250-1350°C. Reactions in the SO - the formula of activity coefficients of liquid solutions based on the 2 O -CH system proceed at a high rate at temperatures within 1100- infinite dilute solutions at some temperature. The linear relationship 2 4 1300°C to form reducing-sulfiding agents: H S, S, COS, CO, CO , H , of logarithm of activity coefficients of binary dilute solutions versus 2 2 2 H O. The required amount of the gas mixture is in the order of 100- reciprocal absolute temperature was verified in good agreement with 2 150 Nm3 per 1 tonne of slag. A decrease in the ferric iron concentra- the experimental values from the literature. The Monte-Carlo algo- tion (Fe3+) from 10-15% to 2-3% results in lower copper solubility in rithm was used to calculate the nonlinear end value equations of binary slag, while agitation of the melt with gas leads to an accelerated sepa- systems, and then the free volume parameters obtained were directly ration of the sulfide phase formed and the slag. The copper content of correlated with the activity coefficients of liquid binary, ternary, qua- the final slag is about 0,12-0,14%. The yield of bottom matte is 7- ternary, and quinary systems at an arbitrary temperature. The three 10% of the weight of the slag processed and its copper content is about dimensional diagrams of a-x-T of some binary systems representing 12-15%. The matte with a copper content of 50-55% sent to convert- the temperature and concentration dependence of activities were plot- ing is a mixture of bottom phases from two zones of the smelting ted. The calculated results regarding non-ferrous alloy systems have furnace, i.e., from the settling zone and from the slag decopperizing been statistically examined with the experimental values from the zone. Off-gases from both zones are mixed inside the furnace and sent literature. Hence, this simple approach could be useful for analyzing to a sulfuric acid plant. This process has been proposed for commercial thermodynamic properties of liquid alloy systems. introduction at two smelters in Russia and the CIS Republics. 3:15 PM Break 3:30 PM Viscosities of Some Binary and Ternary Slags in the System CaO-FeO-SiO2 with CaF2 Additions: Fatemeh Shahbazian1; High-Temperature Superconductors: Sichen Du1; Seshadri Seetharaman1; 1Royal Institute of Technology, Synthesis & Processing Metallu., Brinellv. 23, Stockholm 100 44 Sweden Among the physical properties of slags, viscosity is very important Sponsored by: Electronic, Magnetic & Photonic Materials in understanding the mass transfer phenomena in metallurgical pro- Division, Structural Materials Division, Superconducting cesses. The viscosities of fayalitic slags are of great interest in the Materials Committee non-ferrous metal industry, with special reference to copper produc- Program Organizers: U. Balu Balachandran, Argonne tion. In an attempt to systematize the knowledge on slag viscosities, National Laboratory, Argonne, IL 60439 USA; Pradeep the present work was carried out. The viscosities of CaO-SiO , “FeO”- 2 Haldar, Intermagnetics General Corporation, Latham, NY SiO2 and CaO-”FeO”-SiO2 slags with CaF2 additions were carried out in the temperature range 1438-1762 K. The rotating cylinder method 12110-0461 USA; Chandra Pande, Naval Research Labora- was used in the viscosity measurements. Crucibles and spindles made tory, Materials Science and Technology Division, Washing- out of pure iron were employed. The slags were prefused before the ton, DC 20375-5000 USA measurements. In order to take into account the vaporization reac-

tions involving CaF2, pre- and post measurement samples of the slags were chemically analysed and the compositions were ascertained. The Monday PM Room: Canal D

results show that in the case of the CaO-SiO2 system, CaF2 additions March 13, 2000 Location: Opryland Convention Center tend to decrease the viscosity, in accordance with the expectations. In the case of the “FeO”-SiO2 system, at higher “FeO”/SiO2 ratios in the Session Chair: Donglu Shi, University of Cincinnati, 498 slags, a reverse trend was observed. The measurements in the CaO- Rhodes Hall, Cincinnati, OH 45221 USA ”FeO”-SiO2-CaF2 system indicate that the trends in this case are some-

what similar to the CaO-SiO2 system. The results are discussed on the basis of a viscosity model for silicate melts developed in the present 2:00 PM Invited laboratory as well as the structural considerations of silicates. Dopants in Processing of High Temperature Superconductors: Sharmila Mitra Mukhopadhyay1; 1Wright State University, Mech. & 3:55 PM Matls. Eng., Colonel Glenn Hwy., Dayton, OH 45432 USA The Viscosity of Liquid Lead-Tin Alloys and its Temperature The possibilities of “Dopant enhanced texturing (DET)” of Dependence: José Deodoro Trani Capocchi1; 1University of São perovskite superconductors will be discussed. It is seen that an anionic Paulo, Dept. of Metallu. and Matls. Eng., Polytechnic School, Av. dopant such as Br on the surface of superconducting Y-Ba-Cu-O (YBCO) Prof. Mello Moraes, 2463, São Paulo, SP 05508-900 Brazil results in enhancement of sintering and grain growth rates without any Viscosity of liquid Pb-Sn alloys has been measured by the rotational adverse compositional or crystallographic changes. This effect will be viscometer method in the temperature range from 50 K above their compared with that of a cationic dopant (Yb) that lowers the eutectic respective liquidus temperature to 823 K. The results are accurate to temperature of the 123 structure. Our studies indicate that these dopants within ±1.0%. The variation of viscosity with temperature followed may cause activated sintering and/or enhanced liquid phase sintering. the Arrhenius-type equation m=m .exp(Q/RT). The composition depen- 0 Possible atomistic mechanisms underlying all these effects will be dis- dence of the isothermal viscosity and the activation energy for vis- cussed. Since large domain sizes and preferred orientations are key to cous flow has not shown anomalous changes at the eutectic composi- electrical and levitation properties of these materials, the possibility tion of the Pb-Sn system. of adding a dopant that increases grain growth rate without increasing 4:20 PM processing temperature may be very useful in controlling texture. Removal of Copper from Slags with the Aid of Reducing and Future studies that can make this a technological reality will be dis- Sulfiding Gas Mixtures: Andrey V. Tarasov1; S. D. Klushin1; cussed. 1Gintsvetmet Institute, State Rsch. Instit. of Non-Ferrous Metals, 13 Acad. Korolyov St., Moscow 129515 Russia 38 2:30 PM Invited during final heat treatment. The role of Ag2O during BSCCO-RFAST is Dislocations and Plastic Flow in Flux-Line Lattices of High- discussed. Temperature Superconductors: David O. Welch1; 1Brookhaven National Laboratory, Dept. of Appl. Sci., Bldg. 480, P.O. Box 5000, Upton, NY 11973-5000 USA Since the classic work of E. J. Kramer1 and many others during the Hume Rothery Award Symposium; 1970’s, it is known that for conventional superconductors, under conditions which depend on the magnetic flux density and the density, Phase Transformations and Evolution topology, and spatial distribution of pinning centers, the onset of flux in Materials: Session I flow, and thus the critical current density (J ), results from the plastic c Sponsored by: Structural Materials Division, Electronic, deformation of the flux line lattice. Recently by means of advanced methods of electron microscopy, Tonomura et al.2 have imaged a Magnetic & Photonic Materials Division, Alloy Phases

variety of types of plastic flow in FLLs within Bi2Sr2CaCu2O8+δ crystals. Committee Previously, within the context of a simple analytical theory based on Program Organizers: Patrice E.A. Turchi, Lawrence the theory of dislocations and plastic flow in metals and alloys, I have Livermore National Laboratory, Materials Science and MONDAY PM MONDAY shown how stress states arise in FLLs and discussed the role of tem- Technology Division, Livermore, CA 94551 USA; Antonios perature, current density, and pinning center strength, topology, and distribution in determining whether plastic shear of the FLL or Gonis, Lawrence Livermore National Laboratory, Livermore, depinning limits the critical current density.3 In this paper, I will dis- CA 94551-0808 USA cuss how the character of dislocations in the FLL and its consequent shear strength depend on the anisotropic, layered nature of cuprate Monday PM Room: Johnson A/B superconductors and will describe a theory of flux creep, flux flow, and March 13, 2000 Location: Opryland Convention Center the EJ characteristics of HTS materials based on dislocations and the plasticity of FLLs in cuprates. 1.E. J. Kramer, J. Appl. Phys. 49, 1360 (1973). 2.A. Tonomura et al., Nature 397, 308 (1999). 3.D. O. Welch, Session Chairs: Robert W. Cahn, FRS, Cambridge Univer- IEEE Trans. Appl. Supercond. 3, 1476 (1993). This research was sity, Matls. Sci. and Metallu., Cambridge CB2 3QZ England; supported by the US. Department of energy, Division of Materials Peter W. Voorhees, Northwestern University, Matls. Sci. and Sciences, Office of Basic Energy Sciences under Contract No. DE- Eng. Dept., Evanston, IL USA AC02-98CH10886. 3:00 PM Invited 2:00 PM Opening Remarks Congruent Growth Mechanism of Peritectic Phase in Under- cooled Nd-Based Superconducting Oxides: Kosuke Nagashio1; 2:05 PM Keynote Yuzuru Takamura2; Kazuhiko Kuribayashi2; Yuh Shiohara3; 1The Uni- Theoretical Characterization of Alloy Structures at Microscopic versity of Tokyo, Matls. Sci. Dept., 7-3-1 Hongo, Bunkyo-Ku, Tokyo and Mesoscopic Scales: Armen G. Khachaturyan1; 1Rutgers Univer- 113-8656 Japan; 2The Institute of Space and Astronautical Science, 3- sity, Cer. and Matls. Eng. Dept., Piscataway, NJ 08855-0909 USA 1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510 Japan; 3Supercon- Development of the theory of alloy structure from atomic to ductivity Research Laboratory, ISTEC, 1-10-13 Shinonome, Koto-ku, nanoscale level is discussed. It is shown that the structure on the Tokyo 135 Japan atomic scale is described by the occupation probability function, which

Congruent growth mechanism of a peritectic phase, NdBa2Cu2O7-x can be formulated in terms of Static Concentration Waves. Amplitudes

(Nd123), from undercooled melt below a peritectic temperature (Tp) is of the waves are the long-range order parameters, the wave vectors are discussed from the viewpoint of a phase selection theory based on a the superlattice reciprocal lattice vectors. This approach is especially competitive growth in the peritectic system for free growth condi- effective in the mean-field approximation. However, it was also suc- tion. The seeding experiment to clarify the temperature dependence cessfully used if the correlation effects are taken into account. The of phase appearance shows that the volume fraction of Nd123 drasti- Concentration Wave method describes both the atomic scale and the cally increased when the seeding was carried out at the temperature nanoscale (if the variation of lro parameters becomes considerable).

below Tp. The growth velocity of the Nd123 phase measured concur- With this feature, this method provides a bridge between the scales. It rently well agreed with the theoretical calculation based on the phase is shown how this method can be used to make an accurate transition selection theory where it was assumed that melting point of the Nd123 to the Phase Field theory of evolution of the microstructure on the

phase is Tp and the Nd123 phase grow congruently from undercooled mesoscopic scale. The Phase Field theory of the mesoscopic micro-

melt below Tp. These results suggest that the driving force of the structure evolution in coherent structurally inhomogeneous alloys with

Nd123 phase is activated below Tp, not the hypothetical congruent multivariant domains of ordered intermetallics is discussed. The evolu- melting point. tion is driven by the minimization of transformation strain. This theory is based on the Phase Field micromechanics incorporated in the 3:30 PM Invited alloy thermodynamics. This approach allows one to realistically simu- Reactive Field Assisted Sintering of BSCCO-Ag O Ceramic 2 late the mesoscopic microstructure evolution for a wide spectrum of Produced from Freeze Dried Precursor Powders: Petre Badica1; materials (metal and ceramics) with different types of transforma- George Aldica1; Joanna R. Groza2; M. C. Bunescu3; S. Mandache1; 1Na- tions (diffusional and displacive). Input data required to carry out the tional Institute for Materials Physics, POB MG-7, Bucharest, Magurele computer simulation are the crystal lattice parameters, compositions R-76900 Romania; 2University of California-Davis, Chem. Eng. and and elastic moduli of phases, and the interfacial energy. Mat. Sci. Depts., One Shields Ave., Davis, CA 95616 USA; 3Metav- S.A., Pob 18/3, Bucharest, Romania 3:00 PM Invited Nitrate freeze dried powder (Bi:Pb:Sr:Ca:Cu=1.7:0.3:2.0:2.5:3.5) was Application of Khachaturyan’s Elasticity Theory to Modeling decomposed at 750°C for 60 min. in air and mixed with commercial Coherent Phase Transformations and Structural Defects: Long- 1 1 Ag2O (1.2% wt.). Two types of samples with and without silver oxide Qing Chen ; Penn State University, Matl. Sci. and Eng. Dept., 118 addition were processed by Reactive-Field-Assisted-Sintering Tech- Steidle Bldg., University Park, PA 16802 USA nique (RFAST) at 750°C for 4 minutes under a pressure of 17.5 MPa in One of many Khachaturyan’s major contributions to materials sci- vacuum. Final heat treatments were applied at 800-870°C for 70-200 ence is his elasticity theory for any arbitrary coherent microstruc- h. RFAST-pellets produced from precursor powder with and without tures. It has become a routine tool for many experimentalists to pre-

Ag2O have shown different behavior. Reaction of 2212-phase forma- dict the equilibrium shapes and habit planes of precipitates using inde-

tion during RFAST was sluggish in Ag2O-BSCCO pellets. No 2223- pendent parameters such as lattice parameters and surface energy, and phase could be observed after RFAST processing, but this phase formed to interpret their experimental observations. In the last few years, it 39 has also become an integral part of phase-field modeling of coherent Coherency-induced ordering in a substitutional alloy is examined in a phase transformations in solids. In this talk, a brief review will be given simple model with a two-dimensional square lattice. When both elastic for the application of Khachaturyan’s elasticity theory to phase-field and chemical interactions join together for ordering, the order-disor- MONDAY PM simulation of microstructure evolution during coherent phase trans- der transition temperature is raised to a value greater than the sum of formations. In particular, the effect of an applied external load (strain/ the two individual cases. Other aspects of elastic inhomogeneity ef- stress) or internal stress fields created by local defects such as disloca- fects, including a case with tetragonal misfit strains, will be discussed. tions and point defects will be discussed. A simple method for introduc- 4:45 PM Invited ing the local fields created by structural defects into the phase-field Generalized Phase Field Modeling of Microstructural Evolu- model of coherent phase transformations will be presented. This method tion in Solids: Incorporation of Rigid-Body Motion of Grains will be applied to the diffusional nucleation and growth of coherent and Mobility/Energy Anisotropy of Grain Boundaries: Yunzhi precipitates at dislocations and the effect of local tetragonal distor- Wang1; Andrei Kazaryan2; Chen Shen1; Bruce R. Patton2; 1The Ohio tions on a cubic to tetragonal transformation. It will be shown that State University, Matls. Sci. and Eng., 2041 College Rd., Columbus, structural defects can have a significant influence on coherent phase OH 43210 USA; 2The Ohio State University, Phys. Dept., 174 W. transformations. For example, nucleation at a dislocation may be- 18th Ave., Columbus, OH 43210 USA come barrierless as a result of coupling between the coherency strain The phase field approach to microstructural evolution during solid and the local fields by the dislocations. state phase transformations, originally popularized by Armen 3:30 PM Break Khachaturyan and his coworkers, has received an increasing amount of attention in the last few years. Several reasons may have contributed 3:45 PM Invited to its popularity. For example, it is able to simulate realistic micro- Gamma’ Precipitate Shape Evolution and Splitting in Ni-Based structures and their evolution during both diffusional and diffusionless Alloys: Alan J. Ardell1; Dongman Kim1; 1University of California- transformations under conditions of high volume fraction, elastic in- Los Angeles, Matls. Sci. and Eng., 6531-G BH, Los Angeles, CA 90024- teractions arising from both internal lattice misfit and external fields, 1595 USA and multiple ordered domains and orientation variants. However, mod- It is well known that the shapes of gamma’-type (Ni3X, X = Al, Si, eling microstructural evolution in solids containing grain boundaries Ti and combinations thereof) precipitates in aged Ni-X alloys change and free surfaces demands that the model accounts for the movement from spheres to cuboids as their size increases. When the volume of individual particle as a rigid body. Further more, the mobility and fraction is small, generally less than 0.03 to 0.04, the shapes continue energy of grain boundaries are usually anisotropic rather than isotro- to evolve as the particles grow by diffusion-controlled coarsening. pic in may solids. In the current formulation of the phase field model They become nearly perfect cubes, which evolve into a concave cuboi- for solid state microstructural evolutions, both rigid-body motion and dal shape at yet larger sizes. In alloys cooled directly from the solu- crystal anisotropy are not considered. In this presentation, recent tion-treatment temperature to the aging temperature the concave efforts in extending the phase field method for simulating phenomena cuboidal particles undergo splitting transitions into either pairs of such as sintering and anisotropic grain growth will be discussed in the parallel plates or groups of 8 cuboids. These types of transitions are context of incorporating rigid-body motion of grains and mobility/ consistent with predictions of computer simulation experiments of energy anisotropy of grain boundaries. These advances allow different Khachaturyan and his co-workers. In alloys that are quenched and phenomena occurring during sintering and similar processes to be simu- aged, which is the typical heat-treatment procedure in our laboratory, lated in a single, consistent methodology. A number of problems which the evolution of shapes into concave cuboids is observed, but splitting require consideration of rigid-body motion and anisotropic grain bound- of these particles (Ni3Al and Ni3Ti, for example) has not been seen. ary properties will be addressed. Experiments are in progress to determine whether there is something inherent in the heat-treatment procedure that stimulates the splitting transition. We will also present the results of aging experiments on Ni- Ga and Ni-Ge alloys containing small volume fractions of Ni3Ga and Ni3Ge, in which the shape transitions have not been previously characterized. This research is supported by the National Science Founda- tion. 4:15 PM Invited Coherency Strain in Elastically Inhomogeneous Systems: Jong K. Lee1; 1Michigan Technological University, Dept. of Metallu. and Matls. Eng., 1400 Townsend Dr., Houghton, MI 49931 USA Professor Khachaturyan advanced a multitude of seminal works on strain effects in crystalline solids, especially in elastically homogeneous systems. His theories shed light, among others, on the role of both elastic anisotropy and tetragonal misfit strain, which led us to clear understanding of particle splitting in nickel-based superalloys and strain-induced ordering behavior in interstitial alloys. This presentation is to complement his works with recent findings on coherency strain effects in elastically inhomogeneous systems, i.e., in solids where the competing phases have different elastic constants. The origin for particle splitting has been usually understood in terms of anisotropic strain energy. This view is incomplete in light of recent theoretical works demonstrating that a particle in an isotropic system splits into multiple particlets. Splitting phenomena can be classified into a com- mensurate and an incommensurate elastic instability. In the former, a non-equilibrium elastic state may cause particle splitting provided that relaxation of the excess strain energy can overwhelm the accompanying interfacial energy increase. The second case of incommensurate instability arises when the anisotropy ratios of the precipitate and matrix phase have opposite signs, for example, when the elastically soft direction of the matrix is parallel to the hard direction of the particle phase. One of the driving forces for ordering is long known to be the relaxation of strain energy due to difference in atomic size. 40 3:00 PM Laminated Object Manufacturing (LOM): Mukesh K. Agarwala1; International Symposium on Global 1University of Dayton, Rsch. Instit., 300 College Park, Dayton, OH 45469-0172 USA Innovations in Materials Processing Laminated Object Manufacturing (LOM) is a Rapid Prototyping and Manufacturing: Tutorials and process that uses feed materials in the form of sheets. The LOM process fabricates a part by laminating sheets of material and cutting Overviews of Solid Free Form out cross-sections on each sheet layer. Commercially the LOM pro- Fabrication Techniques cess offers adhesive backed paper as the material of choice to its users. The fabricated LOM parts from paper appear like wood models and are Sponsored by: Materials Processing and Manufacturing used in a variety of applications. This tutorial will discuss the basics of Division the LOM process and review the state-of-the-art in LOM technology. Program Organizers: David L. Bourell, University of Texas, Due to sheet based processing, the LOM process has also been devel- Mechanical Engineering Department, Austin, TX 78712- oped to use green ceramic and metal sheet materials to fabricate ceramic and metal parts. Developments in the LOM processing of ce-

1063 USA; Iver Anderson, Iowa State University, Ames PM MONDAY ramic, metal, and fiber reinforced composites will also be reviewed. Laboratory, Ames, IA 50011-3020 USA; James W. Sears, Lockheed Martin, KAPL Inc., D2, 114, Schenectedy, NY 3:30 PM Break 12301 USA; John E. Smugeresky, Sandia National Laborato- 3:40 PM ries, Department 8724, Livermore, CA 94551-0969 USA; Dan Fused Deposition Modeling (FDM): Mukesh K. Agarwala1; 1Uni- J. Thoma, Los Alamos National Laboratory, Materials versity of Dayton, Rsch. Instit., 300 College Park, Dayton, OH 45469- 0172 USA Science and Technology, Los Alamos, NM 87545-0001 USA; Fused Deposition Modeling (FDM) is a Rapid Prototyping process Srinath Viswanathan, Oak Ridge National Laboratory, Oak that extrudes and deposits a thermoplastic material in selective areas Ridge, TN 37831-6083 USA; Rob Wagoner, The Ohio State as defined by the CAD data. The extruded material solidifies as it is University, Department of Materials Science and Engineer- deposited onto a substrate or onto previously built layers. Commer- ing, Columbus, OH 43210 USA cially the process offers a variety of thermoplastic materials for fabrication of prototypes. The FDM thermoplastic parts can be used in a variety of applications, including certain functional applications. This Monday PM Room: Canal E tutorial will describe the FDM process and review the state-of-the-art March 13, 2000 Location: Opryland Convention Center in the FDM technology. Several developments are currently underway to apply the FDM technology to the processing of ceramics and met- Session Chair: John E. Smugeresky, Sandia National als. Ceramic and metal processing by FDM process employs a powder injection molding type of green feedstock to fabricate green ceramic Laboratory, Dept. 8724, Livermore, CA 94551 USA and metal components. This presentation will review the developments taking place in the FDM processing of metals and ceramics. 2:00 PM 4:10 PM Overview of Direct Fabrication Processes and Materials-An Tutorial on Selective Laser Sintering: Christian Nelson1; David 1 1 Industrial User Perspective: W. R. Schmidt ; D. L. Anton ; A. F. Bourell2; 1DTM Corporation, 1611 Headway Circle, Bldg. 2, Austin, 1 1 Giamei ; United Technologies Research Center, East Hartford, CT TX 78754 USA; 2University of Texas, Mech. Eng., MC C2200, Aus- 06108 USA tin, TX 78712-1063 USA Computer-based design and visualization technologies are critical The SLS Selective Laser Sintering process is a rapid prototyping for achieving significant reductions in time-to-market for new prod- (RP) process which uses a laser to selectively fuse powdered materials ucts and production parts. In parallel with this revolution has been the together, creating objects layer by layer. The SLS process has the development of additive manufacturing technologies, which can rap- unique advantage of processing a broad range of materials in a single idly and directly render these complex computer-based ideas into physical RP platform. Plastic, ceramic, and metal material systems are com- articles via a Solid Freeform Fabrication (SFF) process. SFF opportuni- mercially available, and the development of new materials is ongoing ties exist when conventional manufacturing techniques cannot easily at a number of universities in around the world. This discussion will be used, due either to high processing costs, one-of-a-kind or low touch on the technical issues of processing the different types of volume production levels, geometry limitations, long lead times, and/ material systems, but will focus on the processing of two types of or specialty materials. This presentation will provide an overview of metal material systems. several commercial and developmental techniques for directly fabricating parts and tools for aerospace or commercial use, including a 4:40 PM description of planned usage in the manufacturing environment. Ex- Tutorial on Selective Area Laser Deposition (SALD) of Ceram- amples of current capabilities, limitations, and challenges, along with ics: Harris Marcus1; 1University of Connecticut, Instit. of Matls. Sci., a wish list of process and product attributes will be discussed. Storrs, CT 06269-3136 USA The processing necessary to do solid freeform fabricating (SFF) 2:30 PM from vapor phase precursors will be described. Included will be a de- 1 1 Tutorial on Stereolithography: Paul F. Jacobs ; Express Tool, scription of the processing instrumentation used. The nature of the Warwick, RI USA gas/laser beam interactions and specific systems studied will be de- This presentation will explain the fundamental principles underly- scribed. This will include both selective area laser deposition (SALD) ing the stereolithography process. Information will be provided re- and SALD vapor infiltration (SALDVI) SFF approaches. SALD is di- garding the nature of the UV laser radiation/photopolymer reaction, rect writing from the localized decomposition from the gas phase and the log linear “working curve” relationship between cure depth and SALDVI involves infiltration into powder layers to create the SFF laser exposure, the basic parabolic cylinder cured volume element, and shapes. The range of processing parameters and their influence on the the functional dependence of the cured line-width. The evolution of character of the deposits will be described. build styles, from “Tri-Hatch” to “WEAVE” to “STAR-WEAVE” to ACES and QuickCast will also be covered. Specific applications in- 5:10 PM volving the generation of QuickCast Patterns for the investment cast- Overview of Rapid Solidification Phenomena in Direct Metal ing of functional metal components, the use of ACES models for Deposited Materials: Dan J. Thoma1; John E. Smugeresky2; 1Los photo-stress analysis, and the Direct AIM process for prototype plas- Alamos National Laboratory, Los Alamos, NM 87545 USA; 2Sandia tic injection molding will also be described. National Laboratory, Livermore, CA 94551 USA 41 Direct metal deposition processes display microstructures that are K for 2 hours. Radioactive 57Co tracers diffused into an iridium poly- consistent with rapid solidification phenomena. For example, a con- crystal at 500K under conditions of preferable intercrystallite diffu-

MONDAY PM tinuous liquid/solid interface is maintained while achieving constant sion (at temperatures below 800K). The examination by the method cooling rates that can be varied between 10 to 105 K s-1 and solidifica- of nuclear gamma resonance spectroscopy showed that only two types tion growth rates (that scale with the beam velocity) ranging up to 10- of states in the intercrystallite diffusion (ICD) zone, one in the core of 2 m s-1. Moreover, microsegregation profiles do not necessarily adhere the intercrystallite conjugation regions and the other in adjacent re- to interfacial equilibrium conditions at the solid/liquid interface. The gions of the lattice, were populated even at extremely low tempera- rapid solidification results from approximately 100 micron layers be- tures of the diffusion introduction of the 57Co atomic probe in poly-Ir. ing epitaxially deposited onto a cooled, prior substrate. Traditional These states differed by isomer shifts, local Debye temperatures, and rapid solidification techniques rely on at least one thin dimension Curie temperatures of magnetic ordering of residual magnetic active from which heat can be rapidly removed. Direct metal deposition impurities. techniques also rely on a thin deposition layer, but permits bulk rapidly 2:50 PM solidified samples to be produced. The characterization of the rapid An Atomistic Study of the Dislocation Core Structure and In- solidification behavior and the implications related to the properties teratomic Interaction Potentials in Iridium and Rhodium: of fabricated materials will be discussed. Ludmila Yakovenkova1; Bella Greenberg1; Yurii Shamanaev1; Lidia Karkina1; 1Institute of Metal Physics, Ural Div. of Russian Acad. of Sci., Ekaterinburg 620219 Russia The interatomic potential for Ir, which describes with high accu- International Symposium on Iridium: racy phonon spectra, lattice properties, including energy characteris- Structures and Properties tics of point defects was obtained. The analogous potential is plotted for Rh. The structure and energy stacking faults as well as dislocation Sponsored by: Structural Materials Division, Refractory core was calculated by computer simulation method. Simulation of Metals Committee screw and edge dislocations showed that these split effectively on the Program Organizers: Evan K. Ohriner, Oak Ridge National {111} planes. Comparative analysis of the structure and energy of Laboratory, Oak Ridge, TN 37831-6083 USA; H. Harada, {110} planar defects in Ir, Rh and Cu was carried out. It is shown that, National Research Institute for Metals, Tsukuba, Ibaraki 305 contrary to the case of copper, the stacking-fault-energy surfaces of iridium and rhodium exhibit minima for the shear by the vector a/ Japan; R. D. Lanam, Engelhard-CLAL, Careret, NJ 07008 4<110>. Analysis of the gain in energy upon dissociation of the a/ USA; Peter Panfilov, Ural State University, Ekatrinburg 2<110> dislocations shows that in iridium and rhodium this dislocation 62001 Russia dissociates into two a/4<110> partials on the {110} planes. 3:10 PM Monday PM Room: Jackson A/B Investigations of Microstructure-Property-Relationships in Iri- March 13, 2000 Location: Opryland Convention Center dium: J. Merker1; D. F. Lupton1; H. -J. Ullrich2; M. Schlaubitz3; B. Fischer4; 1W. C. Heraeus GmbH & Company KG, Matls. Tech. Div., 2 Session Chairs: Hiroshi Harada, National Research Dev. Dept., Heraeusstrasse 12-14, Hanau D-63450 Germany; Techni- cal University Dresden; 3Infineon Technologies Dresden GmbH & Com- Institute for Metals, Ibaraki 305-0047 Japan; Joseph G. pany OHG; 4University of Applied Science, Jena Biondo, Engelhard-CLAL LP, Cateret, NJ 07008 USA Because of its chemical stability and the high melting point of 2454°C iridium is especially suitable for applications at the highest temperatures. In spite of its face-centered cubic lattice structure iri- 2:00 PM Invited dium, even of very high purity, tends to brittle behaviour both in hot On Specific Features in Mechanical Behaviour of Iridium: P. and cold forming. It shows unusually strong work hardening in form- Panfilov1; 1Urals State University, Lab. of Strength, Ekaterinburg ing. Therefore, the formability of iridium presents a technical prob- 62001 Russia lem in the manufacturing of semi- and finished products. The form- There is only one face centred cubic metal whose mechanical ability and the strength properties are essentially influenced by the behaviour may be called “puzzling.” Many tests have shown that high generation of lattice distortions during forming. In the same way, the purity iridium could be both a highly plastic and a brittle substance influence of trace impurities on mechanical properties is known. In- simultaneously. This anomaly is the subject of this paper. Octahedral vestigations by means of the back reflection X-ray divergent beam slip is the main deformation mechanism in iridium, while the contribu- technique and the Kossel technique stimulated by an electron beam tions of mechanical twinning and other mechanisms are insufficient were accomplished at the TU Dresden as a contribution to explaining for deformation over wide temperature ranges. Brittle transcrystalline the causes of brittleness. The Kossel technique stimulated by an elec- fracture or cleavage is the inherent tensile fracture mode observed in tron beam shows a high sensitivity with regard to mechanically influ- the necked region of polycrystalline samples or after considerable enced surfaces. It was possible to eliminate the influence of the surface elongation of single crystals. Analysis of the evolution of work-hardened layer on the generation of Kossel interferences by transcrystalline cracks has shown that the inclination to cleavage is a using high energy and high intensity synchrotron radiation. The influ- property of bulk crystals. Recrystallization leads to catastrophic de- ence of selected manufacturing conditions (rolling and annealing con- crease in the plasticity of iridium: grain boundaries are dangerous places ditions) on the real structure of compact samples was shown by using in polycrystalline metal. However, the intercrystalline brittleness of the back reflection X-ray divergent beam technique. High dislocation iridium does not depend on contaminants only. densities, local mechanical distortions in the lattice and small angle 2:30 PM grain boundaries were indicated. These are the main reasons for the Types and Fundamental Properties of States Occupied by 57 Co difficult processing of iridium. By means of microhardness measure- Atomic Probes in the Grain-Boundary Core and Adjacent Re- ment under testing force, both the elastic and plastic components of gions of the Lattice in Polycrystalline Iridium: V. N. Kaigorodov1; the impression and deformation processes were determined. Signifi- S. M. Klotsman1; A. V. Ermakov2; V. K. Rudenko2; A. N. Timofeev1; N. cant differences in the hardness were indicated dependent on the dif- I. Timofeev2; 1Institute of Metal Physics, Urals Div. of Russian Acad. ferent manufacturing conditions. These results correspond with the of Sci., S. Kovalevskaya 18, Ekaterinburg 620219 Russia; 2Non-Fer- investigated dislocation densities. rous Metals Processing Plant, The Head of Rsch. Ctr., Lenin Ave. 8, 3:30 PM Break Ekaterinburg 610014 Russia Iridium polycrystals with the grain size of the order of 2-10-4 m were 3:40 PM produced by deformation of a pure (4N) single crystal of iridium at The Distribution of Ir in Ni-Based Single-Crystal Superalloys: 800°C and its recrystallization in a ultra-high vacuum furnace at 1273 H. Murakami1; T. Yokokawa1; Y. Koizumi1; H. Harada1; 1National 42 Research Institute for Metals, High Temp. Matls. 21 Project, 1-2-1 structure of high-temperature modification of ZrIr was previously Sengen, Tsukuba Science, Ibaraki 305-0047 Japan reported to be cubic B2-type (at 1050°C) and of low-temperature The addition of platinum group metals (PGMs) to Ni-based superal- modification-a monoclinic B19-type (at room temperature). The trans- loys are being considered for the next generation superalloys with formation in ZrIr was recorded by means of X-ray, microstructure, higher temperature capabilities. Among PGMs, Ir is of particular in- electric resistivity, and differential thermal analysis methods. Shape terest because of its high melting point and high corrosion resistance. memory effect (SME) for ZrIr was predicted by analogy with ZrRh and In addition, since Ir and Ni both have fcc structure and they form a TiNi. An attempt to reveal SME in ZrIr was previously undertaken but complete solid solution system, a high amount of Ir is expected to be failed. The martensitic phase of ZrIr was identified as a stacking vari- alloyed to Ni-based superalloys without destroying phase stability. This ant of CrB-type structure. The current report presents new finding of study is aimed at investigating the microscopic distribution of Ir in Ni- our study carried out with aim to make clear when the SME would be based single-crystal superalloys. Atom-probe field ion microscopy displayed in ZrIr. The heating and cooling of ZrIr specimen were (APFIM) revealed that Ir atoms have a small preference to be located conducted in two regimes. By the first, speed of cooling and heating in the gamma phase and to substitute for the Al site in the gamma was quite low, about 10°/min. The five cycles (heating up to tempera- ° prime precipitates, which is in agreement with numerical estimations ture above Af, ~940 C, loading, cooling under the load down to tem- ° by cluster variation method (CVM) and Monte Carlo simulations (MCS). perature below Mf, 710 C, unloading, heating again up above Af) were In this presentation, the distribution of other PGMs in Ni-based alloys fulfilled and in each of them the specimen was bent on cooling substan- PM MONDAY is briefly discussed in comparison to Ir-containing alloys. tially but did not reveal the shape restoration on heating. The lack of SME in ZrIr as compared to ZrRh (in spite of isostructurality in both 4:00 PM origin and martensitic phases, similarity of shape of both electric The Effect of Deformation and Annealing Conditions on Re- resistivity and thermal curves) was suggested to be due to increased crystallization of Deformed Single Crystals and Polycrystals diffusion processes at higher temperatures. To inhibit diffusion proof Iridium: N. I. Timofeev1; A. V. Ermakov1; S. M. Klotsman2; V. G. cesses in ZrIr, a specimen heating rate of about 100°/scc was used. In Pushin2; V. N. Kaigorodov1; L. I. Yurchenko2; V. K. Rudenko1; A. N. this case, the shape restoration in ZrIr of about 71-75% was observed. Timofeev2; P. E. Panfilov3; 1Ekaterinburg Non-Ferrous Metals Pro- The possibility of the restoration degree increase in ZrIr as well as the cessing Plant, The Head of Rsch. Ctr., Lenin Ave. 8, Ekaterinburg divergence of our data on crystal structure of the ZrIr martensitic 620014 Russia; 2Institute of Metal Physics, Urals Div. of Russian Acad. phase is discussed. of Sci., S. Kovalevskaya 18, Ekaterinburg 620219 Russia; 3Urals State University, Lab. of Strength, Ekaterinburg 62001 Russia 5:00 PM The recrystallization threshold of pure (4N) single crystals of iri- Characteristic Features of High Temperature Properties of Iri- dium was analyzed as a function of the deformation (atmosphere and dium Among FCC Metals: M. I. Katnelson1; A. V. Trefilov2; K. Yu. temperature) and annealing (air or ultra-high vacuum) conditions. Simi- Khoromov2; A. Yu. Rumyantsev2; Yu. N. Gornostyrev1; 1Institute of lar to other FCC metals, primary recrystallization of iridium was ob- Metal Physics, Urals Brnch. Russian Acad. of Sci., Ekaterinburg 620219 2 served at 0.3-0.4 Tmelt (Tmelt-Ir melting point) after it was deformed in Russia; Kurchatov Institute Russian Science Center, Moscow 123182 a “jacket” at room temperature and annealed under a ultra-high vacuum. Russia The dispersion in the entire Brillouin zone and the temperature 4:20 PM dependence (right up to the melting temperature) of the anharmonic Microscopic Theory of Defect Structure and Peculiar Mechani- frequency shift and phonon damping in a number of FCC metals is cal Properties of Iridium: Yu. N. Gornostyrev1; O. N. Mriasov2; A. investigated on the basis of microscopic calculations. It is found that J. Freeman2; N. I. Medvedeva3; M. I. Katsnelson1; A. V. Trefilov4; the anharmonic effects depend sharply on the wave vector in the 1Russian Academy of Sciences, Instit. of Met. Physics, S. Kovalevskaya directions of the G-X, X-W, and G -L and, in contrast to BCC metals, 18, Ekaterinburg 620219 Russia; 2Northwestern University, Dept. of the magnitude of the effects is not due to the softness of the initial Phys. and Astronomy, Evanston, IL 60208-3112 USA; 3Institute of phonon spectrum. It is shown that the relative frequency shifts and Solid State Chemistry, Pervomaiskaya str. 91, Ekaterinburg 620219 the phonon damping near melting do not exceed 10-20%. The relative Russia; 4Kurchatov Institute, Russian Sci. Ctr., Kurchatov Sq., Moscow role of various anharmonic processes is examined, and the relation 123182 Russia between the results obtained and existing experimental data is dis- The brittle failure after a long stage of plastic deformation is the cussed. most surprising feature in mechanical properties of Ir and its analog, Rh, separating them from other FCC metals. On the base of ab initio total energy calculations, the peculiarities of the structure and energetic characteristics of defects in Ir (vacancies, dislocation, stacking faults) and cleavage decohesion process are investigated. We have carried out corresponding calculation also for Au which is an example of an FCC metal with a typically ductile behavior. Comparing the dislocation and vacancy formation characteristics (scalable by such factors as melting temperature, or FCC metals). A distinguishing feature of Ir is a relatively small decohesion energy (in comparison with elastic moduli) which leads to its brittle fracture, according to standard Rice-Thomson criteria of brittle-ductile behavior. The reason of this is a peculiar character of chemical bonding which is very strong for small displacements due to ion overlap butdiminishes rapidly with increased distance. 4:40 PM About Martensitic Transformation in ZrIr Compound: Yu V. Kudryavtsev1; E. L. Semenova2; 1Institute of Metal Physics, Acad. of Sci. of Ukraine, Vernadsky str., Kiev 252142 Ukraine; 2I.N. Frantsevich Institute for Problems of Material Science, Acad. of Sci. of Ukraine, Krzhyzhanovsky str., Kiev 252180 Ukraine There is some controversy as to crystal structure and nature of martensitic transformation (MT) in the equiatomic compound ZrIr. The latter is known to relate to the class of compounds formed as a result of interaction between transition metals of IV and VIII groups and to reveal transformation in solid similar to that in TiNi. Crystal 43 The excellent stability of the signal of the calorimeter, ±4nV over a long period of time (>10 days), allows to measure directly the heat evolved during the scan of an hysteresis loop, with an average accu- MONDAY PM Kleppa Symposium on High Tempera- racy of 1%. Kinetic of the phase transformation is based on the analy- ture Thermochemistry of Materials: sis of the measured heat flux, where the true rate law at the sample Session II level is obtained by deconvoluting the measured signal. It is shown that Sponsored by: ASM International: Materials Science only overall informations can be expected; the results of the numerical treatment raise the problem of the location of the heater used for Critical Technology Sector, Extraction & Processing calibration of the calorimeter. Investigations have been carried out

Division, Thermodynamics & Phase Equilibria Committee, with the ZrNi-H2 system. Process Fundamentals Committee 3:00 PM Program Organizers: Ray Y. Lin, University of Cincinnati, Calorimetric Study on Hydration of CaO-Based Oxides: Department of Materials Science and Engineering, Cincin- Yasutaka Iguchi1; Takayuki Narushima2; Chihiro Izumi3; 1Tohoku nati, OH 45221-0012 USA; Y. Austin Chang, University of University, New Industry Creation Hatchery Ctr., Arakaki Aza Aoba, Wisconsin, Department of Materials Science & Engineering, Aoba-ku, Sendai 980-8579 Japan; 2Tohoku University, Dept. of Metallu., Aramaki Aza Aoba, Aoba-ku, Sendai 980-8579 Japan; 3Tohoku Uni- Madison, WI 53706-1595 USA; Dr. Susan Meschel, The versity, Grad. Schl., Aramaki Aza Aoba, Aoba-ku, Sendai 980-8579 University of Chicago, Chicago, IL 60637 USA; Ramana Japan Reddy, University of Alabama, Department of Metals and Weathering disintegration of steelmaking slag is caused by volume Materials Engineering, Tuscaloosa, AL 35487 USA expansion due to the hydration of free-CaO and CaO-based materials in the slag. In the present work, heat of hydration of CaO solid solutions (CaO-MnO and CaO-FeO systems) and CaO compound oxides Monday PM Room: Lincoln E were measured by a solution calorimetric technique and the relation- March 13, 2000 Location: Opryland Convention Center ship between the heat of hydration and expansion due to hydration was clarified for these materials. The heat of hydration was evaluated with Session Chairs: Y. Austin Chang, University of Wisconsin, enthalpy change of a reaction with distilled water at 327K, and the Dept. of Matls. Sci. & Eng., Madison, WI 53706-1595 USA; expansion was determined in an argon-water vapor atmosphere at 353K. Effects of MnO and FeO contents in the solid solution on heat Robert J. Gottschall, US Department of Energy, German- of hydration or expansion were shown. The difference of expansion town, MD 20874-1207 USA rates for CaO compound oxides was discussed from the point of view of hydration products. 2:00 PM 3:30 PM Enthalpies of Formation of NiAl and Compounds in the Al-Ni- The Standard Enthalpies of Formation of the Compounds of Y System: Philip Nash1; Ole Kleppa2; 1IIT, Mmae Dept., 10 W. 32nd Early Transition Metals with Late Transition Metals and with St., Chicago, IL 60616 USA; 2University of Chicago, James Frank Noble Metals as Determined by Kleppa and Co-Workers at the Instit., S. Ellis Ave., Chicago, IL USA University of Chicago-A Review: Qiti Guo1; 1University of Chi- The enthalpy of formation of NiAl as a function of composition cago, James Franck Instit., 5640 S. Ellis Ave., Chicago, IL USA has been determined by high temperature reaction calorimetry. The Since the early 1980’s, experimental studies of the standard enthal- value for the Ni0.5A10.5 composition is -61.0±1.1 kJ/mole. The pies of formation of the binary intermetallic compounds of early enthalpies of formation of the ternary compounds All6Ni3Y, Al4NiY, transition metals with late transition metals and with noble metals and A12NiY and of the binary compound A12Y containing nickel have been a major long-term research project in this laboratory. Tabu- have also been measured. The enthalpy values measured are compared lated in this review are 265 enthalpy of formation values for 252 such to previously published results where available. compounds, all determined in this laboratory during the last two de- 2:30 PM cades. The calorimetric methods used in these investigations have High Temperature Calorimetry in Solid-Gas Reactions: Appli- included solution calorimetry, solute-solvent drop calorimetry, and cation to the Intermetallic Hydride Compounds: P. Dantzer1; direct synthesis calorimetry. Among these methods the direct synthe- 1Universite de Paris-Sud, Cnrs Umr 8647, Bat 415, Orsay, Cedex 91405 sis approach has been the most frequently used technique. In this France review our results will be compared with values published by other laboratories and with values predicted by the Miedema semi-empirical In order to study the intermetallic compounds-H2 systems, one has to consider the problems created by the presence of a powdered acti- model. However, the emphasis will be placed on the systematic varia- vated sample and the manifestation of hysteresis during the formation of the standard enthalpy of formation for some characteristic tion-decomposition of the hydrides. Due to the low thermal conduc- alloy families from group to group in the periodic table. A few ex- tivity of the powder, strong non isothermal behaviors can lead to amples will be presented to show the correlation between the enthalpy strong temperature gradients within the sample, which in turn may of formation and the pertinent atomic number in the binary alloy induce metallic diffusion and disproportionation of the compound. families. Hysteresis implies a non reversible character of the solid phase trans- 4:00 PM Break formation and the possibility of describing different thermodynamic paths during the scan of the hysteresis loops. Solutions to these prob- 4:10 PM lems have been brought by a sharp control of the thermodynamic Analysis of the Enthalpy of Mixing Data of Binary and Ternary variables during the phase transformation. Thus to maintain quasi- (Rare Earth (Nb, La, Y, Yb)-Alkali Metal) Halides Systems: 1 2 1 isothermal conditions, a reliable control of the temperature inside the Marcelle Gaune Escard ; Michael Hoch ; Universite de Provence, sample is insured by optimizing the hydrogen gas flow rate. The mea- IustiI-Cnrs Umr 139, Technopole de Chateau Gombert, 5 rue Enrico 2 surements have been carried out with an automatic apparatus, consist- Fermi, Marseille, Cedex 13 13453 France; University of Cincinnati, ing of a heat flow calorimeter coupled with high precision volumetric Dept. of Matls. Sci. and Eng., Cincinnati, OH 45221-0012 USA devices. It provides accurate characterizations of the thermodynamic We analyzed the enthalpy of mixing data of several liquid Rare properties as well as informations of the dynamic aspects of the hy- Earth–Alkali metal halides using the Hoch-Arpshofen solution model. We investigated the NdCl -MCl (M is Na, K, Rb, Cs,), NdBr -MB (M is dride phase growth, over a wide range of pressures 0-4 MPa and tem- 3 3 r peratures 250-800 K. The ensemble constitutes a closed system in Li, Na, K, Rb, Cs), LaBr3-MBr (M is Li, Na, K, Rb, Cs), (LaF3, YF3, YbF )-MF (M is Li, Na, K, Rb, Cs)” binary systems, and the ternary which high purity hydrogen gas is permanently transferred between 3 NdCl -LiCl-KCl, LaF -NaF-LiF systems in the binary systems the larger hydrides reservoirs and reactors with high thermal transfer capacity. 3 3 the M+ radius, the larger the maximum (in absolute terms) of the 44 enthalpy of mixing. Larger the anion radius L- the smaller the maximum of the enthalpy of mixing. In the binary systems NdL3-ML the maximum of the enthalpy of mixing is given by the equation: Hm max Magnesium Technology 2000: Thermal (in kK) =-(2.392± 0.165)*r + +(0.742±0.112) *r . In the binary M L- Reduction and Environmental Issues systems LaL3-ML the maximum of the enthalpy of minimum is given ± by the equation: Hm max (in kK) +- (2.029 0.179)*rM+ Sponsored by: Light Metals Division, Reactive Metals ± +(0.642 0.133)*rL-. In the ternary system NdCl3-LiCl-KCl along the Committee, International Magnesium Association line NdCl3-(0.58 LiCl + 0.42 KCl) the enthalpy of mixing equals that Program Organizers: Howard I. Kaplan, Magnesium of NdCl3-NaCl, because the weighted average radius of (0.58 Li+ + + + Corporation of America, Salt Lake City, UT 84116 USA; 0.42 K ) equals that of Na . In the ternary system LaF3-NaF-LiF the enthalpy of mixing could be computed from the binary systems. The John N. Hryn, Argonne National Laboratory, Argonne, IL composition of the maximum of the enthalpy of mixing depends on 60439-4815 USA; Byron B. Clow, International Magnesium the radius of the rare earth and anion. If the rare earth radius is large Association, McLean, VA 22101 USA

compared to the anion radius (La vs F) the maximum is at xMF+ 0.5. if x the rare earth radius is smaller, (Dy vs Cl) the maximum shifts to MV Monday PM Room: Bayou C PM MONDAY + 0.69. March 13, 2000 Location: Opryland Convention Center 4:40 PM Enthalpies of Mixing in Fe-C-Si Melts: Mark E. Schlesinger1; Qinfang Xiang1; 1University of Missouri-Rolla, Dept. of Metallu. Eng., Session Chair: John N. Hryn, Argonne National Labora- 1870 Miner Circle, Rolla, MO 65409-0340 USA tory, Argonne, IL 60439 USA The accuracy of mass and energy balance calculations in iron- and steelmaking is highly dependent on the enthalpy of mixing of molten 2:00 PM iron-based solutions, in particular Fe-C-Si melts. These enthalpies of Fundamentals of Serpentine Leaching in Hydrochloric Acid mixing are difficult to determine experimentally, and as a result are Media: J. E. Dutrizac1; T. T. Chen1; C. W. White2; 1CANMET, 55 calculated using a variety of models derived from Gibbs energy of Booth St., Ottawa, Ontario K1A0G1 Canada; 2Metallurgie Magnola mixing data. A comparison of calculated enthalpies of mixing in the Inc., 620 Rene Levesque W., Montreal, Quebec H3B1N7 Canada Fe-C-Si ternary system is made, using several different modeling ap- In the Magnola process, magnesium metal is produced by the elec- proaches. Featured modeling methods include the regular-solution model trolysis of anhydrous MgCl2 derived from the leaching of serpentine, of Schmid and Wagner’s model for multicomponent dilute solutions. which is the major constituent (>90%) of asbestos tailings. Serpentine The modeling results are compared with experimental data reported by reacts rapidly in concentrated HCl media, and the leaching rate is Vitusevich et al. essentially independent of the rotation speed of disks of the massive 5:10 PM mineral. The implication is that the rate is chemically controlled, and Thermochemical Study on Stability of Zro2 Fine Particles: T. this conclusion is supported by the moderately high temperature de- Mitsuhahsi1; 1National Institute for Research in Inorganic Materials, pendence and the approx. 40 kJ/mol apparent activation energy. At 1-1 Namiki, Tsukuba, Ibaraki 305-0044 Japan 95°C, the leaching rate of the asbestos tailings increases as the 0.5 It is well known that high-temperature tetragonal Zro2 with fine power of the HCl concentration, but is independent of the concentra- particle sizes occurs even at room temperature. Though this problem tions of FeCl3 or FeCl2, for concentrations as high as 1.0 M of either has been discussed from both views of kinetics and thermodynamics, a salt. The accumulation of the MgCl2 reaction product in the leaching clear explanation has not been made. A high-temperature solution solution suppresses the leaching rate, and high total chloride concen- calorimetry may give the clear answer under consideration of heat trations result in the “boiling” of HCl from the solution. The leaching capacity. In the present work, some of tetragonal and monoclinic fine reaction occurs over a diffuse reaction zone up to 400 µm thick. As a particles were prepared. A Calvet twin micro-calorimeter was used to consequence, the leaching rate is nearly independent of the particle measure heats of solution of samples into a solvent. The sample pow- size for serpentine particles less than 600-800 µm in diameter. The implication is that fine grinding of the asbestos tailings is not required. ders were dropped from 298K into 3Na204MoO3 solvent at 970K. Heat capacities were measured from 298K to 900K by DSC method. Mea- The leaching reaction generates soluble magnesium and an amorphous surements of heats of solution gave the values of 9.5 to 18 kJ/mol for silica reaction product. In acid media, only trace silica dissolution t-Zro2 and 21 to 29 kJ/mol for mZro2, respectively. By considering occurs; virtually all of the silica forms an insoluble psuedomorph after surface areas and strain in particles, enthalpy of transition and surface the original serpentine. 2 energy difference between t- and m-Zro were estimated to -12.5kJ/ 2:25 PM 2 mol and 0.1J/m at 298K, respectively. It is clearly concluded under Reduction of Molten MgO-Bearing Slags with Ferroaluminium: 2 consideration of heat capacity data that t-Zro fine particles are ther- José Deodoro Trani Capocchi1; V. Rajakumar2; 1University of São 2 modynamically unstable below 700K, compared with m-Zro fine par- Paulo, Dept. of Metallu. and Matls. Eng., Polytech. Schl., Av. Prof. ticles. Mello Moraes, 2463, São Paulo, SP 05508-900 Brazil; 2CSIRO Miner- 5:40 PM als, Light Met. Product., Clayton, Vic 3172 Australia Spinal Oxide Calorimetry: M. Wakihara Molten slags of the composition 5.6% MgO, 48.1% Al2O3 and Abstract text is unavailable 46.3% CaO were reacted with ferroaluminium (80% Al and 35% Al), in graphite crucibles, at 1435-1450°C and reduced pressure 3,066.36- 8,399.16 Pa(23-63mmHg). A technique was developed for measuring the rate of evolution of magnesium vapour transported from the reaction zone to a condenser, which was continuously weighted by means of a load cell. It was found that, in the range of operating pressures and composition studied the final yield of magnesium increased linearly as the pressure decreased. The rate per unit driving force with the 80% Al-alloy was 4.7 times that with the 35% Al-alloy mainly because of the larger slag/metal interfacial area when the 80% Al-alloy was used. The overall process appears to be controlled by transport in the slag phase and/or a first order reversible reaction taking place at the slag/ metal interface.

45 2:50 PM unstable Al2(SO4)3 was also detected in the crucible scale. These find- Magnesium Metal by the Heggie-Iolaire Process: Michael W. ings support the current proposed mechanism. Further investigations Wadsley1; 1Austherm Pty Limited, P.O. Box 2049, North Brighton,

MONDAY PM were conducted into the use of sulphur dioxide gas mixtures in ingot Victoria 3186 Australia and sow casting of pure magnesium and magnesium die casting alloys. The Heggie-Iolaire Process involves the ambient pressure The results from this study indicate that the use of SO2 gas mixtures for aluminothermic reduction of magnesia derived from magnesite and the protection of molten magnesium may present a safety problem dolomite in a thermal plasma arc furnace using selected sources of under certain operating conditions. However, for some applications, scrap aluminium. Test work has been conducted at the scale of 2.5 kg/ such as ingot casting of magnesium die casting alloys, dilute sulphur hr and 10 kg/hr magnesium metal production rates. This paper pre- dioxide gas mixtures are a viable alternative to SF6. sents some of the results of this test work and of process modeling. A comparison is made between this process and published information 4:15 PM concerning other methods for the metallothermic production of mag- EPA's Voluntary Partnership with the Magnesium Industry for 1 1 nesium metal. The factors affecting the recovery of liquid metal from Climate Protection: Scott Charles Bartos ; U.S. Environmental its vapour are discussed. A comparison is made between the condensa- Protection Agency, Climate Protect. Div., 401 M St. S.W. (6202J), tion of magnesium metal and published information for the commer- Washington, DC 20460 USA cial recovery of liquid zinc metal from its vapour. The U.S. Environmental Protection Agency (EPA) develops and fosters cooperative partnerships with a wide range of industries to 3:15 PM reduce U.S. emissions of greenhouse gases. One such voluntary part- Protective Atmospheres for the Heat Treatment of Magnesium nership is the SF6 Emission Reduction Partnership for the Magnesium Alloys: P. F. Stratton1; E. K. Chang1; 1BOC Gases, European Dev. Industry. Started in 1998, this partnership seeks to reduce the U.S. Ctr., Rother Valley Way, Holbrook, Sheffield S203RP UK magnesium industry’s emissions of the extremely potent greenhouse Most magnesium alloys are used for die castings which, due to the gas, sulfur hexafluoride (SF6). The magnesium industry employs SF6 presence of porous cores, cannot be heat treated at present without to prevent the rapid oxidation and burning that occurs when the mol- blistering. However, as technology improves, pore-free castings will ten metal directly contacts air. A continuous flow (and subsequent become available whose properties can be optimised by heat treatment release) is required to maintain a protective layer of gas at the melt and environmentally friendly protective atmospheres will be required surface. SF6, an odorless and non-toxic gas, has been the industry for mass production processing. The remaining sand cast magnesium- standard for melt protection for more than 20 years. However, the zirconium alloys, mainly used for aerospace components, are cur- industry has recognized that continued emission of this long-lived, rently heat treated. The most common alloy, ZE41, is usually only extremely potent greenhouse gas is a costly and unsustainable business treated to the T5 temper whereas the increasingly popular WE43 is practice and has begun to work with EPA to reduce emissions and treated to T6 temper. During that heat treatment there is a potential evaluate emission control technologies. In response to this environ- fire hazard which can be solved by the correct application of a protec- mental concern, EPA has launched a new initiative to assist the indus- tive atmosphere. There is always a risk of fire in any magnesium heat try in its effort to reduce SF6 emissions. As a voluntary partner, an treatment due to equipment failure or local furnace hot spots. The risk individual magnesium producer or casting company signs a memoran- of ignition is particularly acute for alloys which must be solution dum of understanding (MOU) with EPA committing to annually report treated at over 400°C at which temperature some form of protective their emissions of SF6 and take cost-effective and technically feasible atmosphere has historically always been advised. The atmospheres actions aimed at reducing those emissions. EPA works together with recommended leave a great deal to be desired in terms of effective its industry partners to review and evaluate emission reduction strate- control, toxicity and environmental impact. A study of non-toxic gies and technologies, promote technical information sharing by pre- environmentally friendly alternatives is presented for ZE41 and WE43. paring annual reports and hosting technical conferences, record and One route to pore-free castings is hot isostatic pressing (HIP). If HIP verify the partner’s progress, and provide positive public recognition of magnesium castings is to become a standard process within the for the partners’ achievements. The MOU encourages partners to automotive industry, the cost must not be prohibitive. One way of follow a pollution prevention approach to reduce SF6 emissions. This reducing costs would be to replace the argon pressurisation medium approach, as outlined in the United States Pollution Prevention Act of with nitrogen and the effects of doing so are examined. 1990, presents a hierarchy of emission reduction options that includes 3:40 PM Break source reduction of SF6 by reducing leaks and assuring appropriate cover gas concentrations and flow rates, substitution of SF6 with a 3:50 PM more environmentally benign chemical, capture and reuse of SF6, and The Use of Sulphur Dioxide as a Cover Gas for Molten Magne- lastly, destruction of the chemical before release to the environment. sium: S. P. Cashion1; N. J. Ricketts1; 1Australian Magnesium Corpo- Many companies have already implemented various cost-effective ration, Level 6, 9 Sherwood Rd., Toowong, Queensland 4066 Australia source-reduction efforts including regular inspection and maintenance The use of sulphur dioxide (SO2) as a cover gas component for the of the gas distribution system, installation of central cover gas blend- oxidation protection of molten magnesium is a viable alternative to ing equipment, and analysis of cover gas concentration and distribu- sulphur hexafluoride (SF6). The two major problems with SF6 are its tion at the molten metal’s surface. In addition, a small group of mag- high cost and extremely high Global Warming Potential of approxi- nesium companies are currently evaluating the technical feasibility mately 24,000. In comparison, SO2 is relatively inexpensive and has a and occupational safety concerns associated with installing either SF6 Global Warming Potential of zero. However, there has been some capture/recycle systems or SO2-based alternative cover gas systems. concern regarding the safety of SO2, in particular its use as a cover gas While the casting technologies of magnesium producers are distinctly in high pressure die casting furnaces. During the 1940’s and 1950’s, different from those of casting companies, both rely heavily on SF6 to numerous incidents were reported in magnesium die casting opera- provide crucial melt protection. Seven of the approximately forty tions, occurring in the sulphur domes used to protect the magnesium companies that produce and cast magnesium in the U.S. have joined die casting alloys. This “Sulphur Dome Effect” was attributed to the EPA as partners. As of June 21, 1999, the following companies have formation of magnesium sulphate, resulting from the use of SO2. An signed MOUs with EPA: Acme Die Casting, Chicago White Metal investigation was conducted into the Sulphur Dome Effect. Variables Casting, Del Mar Die Casting, Diemakers, Hyatt Die Cast & Engineer- examined covered the range of processing operations generally expe- ing Corporation, Magnesium Products of America, Spartan Light Metal rienced in primary magnesium production and magnesium die casting. Products. Several more companies are expected to join the partner- The Sulphur Dome Effect was simulated in the laboratory under a ship this year. range of operating conditions. The reaction associated with the Sul- phur Dome Effect appears to occur from a reaction between an accretion on the wall of the crucible and the molten magnesium. Chemical analyses of the accretion and surface film revealed the presence of

MgO and MgSO4 in the surface film and the crucible scale. Highly 46 ticles back to the solder-joint/pad interface, forming a dense, continu-

ous AuSn4 layer. This AuSn4 layer will break off and come back repeatedly upon further reflow-aging cycles. The mechanism for this scien- Packaging & Soldering Technologies tifically very interesting phenomenon remains unknown. Being very

for Electronic Interconnects: Applica- brittle, the AuSn4 layer will severely deteriorate the strength of a solder joint. Therefore, this phenomenon is also technologically very tions of Multicomponent Phase Equilib- important. The purpose of our study is to investigate the mechanism ria in Electronic Packaging for this phenomenon. We will present the most recent results of our Sponsored by: Electronic, Magnetic & Photonic Materials study. It is believed that this phenomenon strongly correlates with the low melting point of AuSn4, high diffusivity of Au in solder, and the Division, Electronic Packaging and Interconnection phase relationships in the Au-Ni-Sn ternary system. Materials Committee Program Organizers: Hareesh Mavoori, Bell Laboratories, 3:05 PM Use of Multicomponent Phase Diagrams for Predicting Phase Murray Hill, NJ 07974 USA; Srini Chada, Motorola, Planta- Evolution in Solder/Conductor Systems: Kejun Zeng1; Weiqun tion, FL 33322 USA; Gautam Ghosh, Northwestern Univer- 1 1 1

Peng ; Jorma Kivilahti ; Helsinki University of Technology, Dept. PM MONDAY sity, Department of Materials Science, Evanston, IL 60208- Elect. and Comm. Eng., Lab. of Elect. Prod. Tech., Otakaari 5A, PL 3108 USA; Martin Weiser, AlliedSignal Electronic Materials, 3000, Espoo FIN-02015 Finland Plated and Discrete Products, Spokane, WA 99216 USA Although the complete phase equilibrium is never reached in interconnection applications, the assumption of local equilibrium at the interfaces is generally valid in most systems composed of dissimilar Monday PM Room: Lincoln D materials. Therefore, the tie lines in ternary (or multicomponent) March 13, 2000 Location: Opryland Convention Center phase diagrams-together with the relevant stability diagrams and the mass balance requirements-can be used for predicting the phase se- Session Chairs: K.-N. Tu, University of California, Dept. of quences (i.e. diffusion paths) formed, for example, in solder/conductor joints. Generally, binary phase diagrams cannot provide sufficient in- Matls. Sci. Eng., Los Angeles, CA 90095 USA; H. Mavoori, formation on the phase formation in a solder/conductor systems be- Bell Laboratories, Murray Hill, NJ 07974 USA cause they do not bear any information on the relative stabilities between different binary phases in multicomponent systems. As examples, the formation of intermetallic compounds in several solder/ 2:00 PM Invited conductor systems with Au- or Cu-metallization was studied with the Phase Equilibria of Sn-In Base Micro-Soldering Alloys: Kiyohito help of ternary phase diagrams as well as experimentally, demonstrat- Ishida1; 1Tohoku University, Dept. of Matls. Sci., Aoba-yama 02, ing the inadequacy of the binary information. The phase diagrams Aoba-ku, Sendai, Miyagi Prefecture 980-8579 Japan were calculated by using the thermodynamic methods. The experi- We recently developed a thermodynamic database for the calcula- mental results confirmed that the dependence of formation of inter- tion of phase diagrams in micro-soldering alloy systems, which con- metallic compounds on temperature and solder composition is clearly sists of the elements Pb, Bi, Sn, Sb, Cu, Ag and Zn. The important represented by the ternary phase diagrams supplemented with the element In was not available at the time. In order to include In in this stability diagrams. database, therefore, the phase equilibria of some In base alloys have been experimentally determined by DSC, EDX, X-ray diffraction, etc., 3:25 PM Break and thermodynamic assessments have been made by CALPHAD 3:40 PM Invited method. In the present paper, the phase equilibria and thermodynamic Thermodynamic Assessment of the Sn-Ag-Cu System: U. R. properties of some Sn-In-X (X: Ag, Zn, Sb, Bi) ternary systems will be Kattner1; K. -W. Moon1; W. J. Boettinger1; C. A. Handwerker1; 1NIST, shown, which have practiced applications in the development of Pb- Metallu. Div., Mail Stop 8555, Gaithersburg, MD 20899 USA free solders with low melting temperatures. Experimental data on the Sn-Ag-Cu system will be summarized. 2:25 PM Alloys in this system are being studied for their potential as Pb-free Growth of a Au-Ni-Sn Intermetallic Compound on the Solder- solders. Thus the location of the ternary eutectic involving L, Sn, 1 Substrate Interface after Aging: Andrew Murphy Minor ; John W. Ag3Sn and Cu6Sn5 phases in the Sn-rich corner is of critical interest. Morris1; 1University of California, Dept. of Matls. Sci. and Min. Eng., Thermodynamic extrapolation of the diagram from the three con- Lawrence Berkeley Labs. Bldg. 66-200, One Cyclotron Rd., Berkeley, stituent binary systems using the CALPHAD method will be presented. CA 94720 USA A comparison to the experimental data will indicate the need for When Ni/Au metallization is used to form joints with eutectic sol- refined binary assessments and/or ternary interaction parameters. For

der, the as-solidified joints have AuSn4 precipitates distributed through- various solder compositions, solidification paths and freezing ranges

out the bulk, with Ni3Sn4 at the interface. Recent work has shown that will be predicted with a Scheil analysis. These predictions will be com- the Au-Sn redeposits onto the interface during aging, compromising pared to experimental solidification results obtained in this work and the strength of the joint. The present work shows that the redeposit is in the literature. a ternary intermetallic Au Ni Sn . While this intermetallic has, to 0.5 0.5 4 4:05 PM our knowledge, not been seen previously, it appears to be a ternary Phase Equilibria and Related Properties of Sn-Ag-Cu Based variant of AuSn . It does not form during the initial soldering since the 4 Pb-free Solder Alloys: I. Ohnuma1; X. J. Liu1; H. Ohtani1; K. Ishida1; solubility of Au in molten Pb-Sn solder separates the Au and Ni con- 1Tohoku University, Dept. of Matls. Sci., Aoba-yama 02, Aoba-ku, stituents. Sendai, Miyagi Prefecture 980-8579 Japan 2:45 PM We recently developed a thermodynamic database for micro-solder-

Formation and Migration of AuSn4 in BGA Solder Joints Hav- ing alloys which consists of the elements Pb, Bi, Sn, Sb, Cu, Ag, Zn, and ing the Au/Ni Surface Finish: C. E. Ho1; Y. M. Chen1; C. Robert In. In this paper, the phase equilibria and the related thermodynamic Kao1; 1National Central University, Dept. of Chem. Eng., Chungli, properties of the Sn-Ag-Cu base alloys are presented using this data- Taiwan base. These alloy systems are promising candidates of Pb-free solders. The Au/Ni two-layer structure is a very common surface finish for The isothermal section diagrams of the Sn-Ag-Cu ternary system were the solder-ball pads in the Ball-Grid-Array (BGA) packages. During experimentally determined by EDX, X-ray diffraction and metallo-

reflow, a layer of AuSn4 will form from the reaction of the Au layer graphic techniques. Based on the present results as well as previous

with Sn in the solder. The AuSn4 layer will subsequently break off and data on phase boundaries, thermodynamic assessments of this system

fall into the solder joints as individual AuSn4 particles. In the past few were carried out. The isothermal and vertical section diagrams, liquidus years, it was found that post-reflow aging will bring these AuSn par- 47 4 surface, mole fractions of the phase constitution etc. have been calculated. Moreover, non-equilibrium solidification process using the Scheil model has been simulated and compared with the equilibrium solidification behavior in some Sn-Ag-Cu base alloys. In addition, the predic- MONDAY PM Pressure Technology Applications in tions of surface energy and viscosity are presented. the Hydrometallurgy of Copper, Nickel, 4:25 PM Ag and Cu Migration Phenomena on Wire-Bonding: Ker-Chang Cobalt and Precious Metals: Pressure Hsieh1; Theo Martens2; 1National Sun Yat-sen University, Instit. of Technology Applications in the Hydro- Matls. Sci. and Eng., Kaohsiung, Taiwan; 2Philips Electronic Building Elements Industries Limited, Tech. Dev. Div., 10, Chin 5th Rd. N.E.P.Z., metallurgy of Gold P.O. Box 35-48, Kaohsiung, Taiwan Sponsored by: Extraction & Processing Division, Copper, ° The plastic packaged sample stored at 250 C for 588hrs and found Nickel, Cobalt Committee the Au plus 1%Pd wire composition changed. The Ag and Cu atoms can migrate from the wedge bond through the wire surface and arrive Program Organizers: James E. Hoffmann, Hoffmann and the ball bond. At the same time, the Ag and Cu atoms diffuse into the Associates, Houston, TX 77242 USA; Norbert L. Piret, Piret gold wire itself and form a layer type structure. These migration phe- & Stolberg Partners, Duisburg 47279 Germany nomena can be explained after detailed microstructure analysis. The microstructure analysis was done by using the apparatus: Joel Superprobe Monday PM Room: Lincoln C JXA-8900R. The quantitative line scan analysis result included the identified phases and phase thickness. A similar line scan analysis was March 13, 2000 Location: Opryland Convention Center done on the ball bond section. The results has the similar layer structure as the wire section. There is two type of driving force for these Session Chairs: Christopher A. Fleming, Lakefield Re- atom migration phenomena. One is the Ag and Cu concentration search Limited, Lakefield, Ontario K0L2H0 Canada; gradient to drive the diffusion process. The other is the new alloy James E. Hoffmann, Hoffmann and Associates, Houston, phases formation, which can reduce the free energy of this alloy system, based on the thermodynamic rules. The phases formation se- TX 77242 USA quence formed on the wire or ball bond section is consistent with the equilibrium Ag-Au-Cu phase diagram. Conclusions: 1. Ag and Cu atoms 2:00 PM can migrate on the wire surface and form new alloy phases. 2. The A Novel Process for the Simultaneous Dissolution of Gold, properties of gold wire will change under high temperature and long Platinum Group Metals and Base Metals: Christopher A. Fleming1; time conditions. 3. The diffusion rate of Cu is higher than Ag accord- C. Joe Ferron1; Dave B. Dreisinger2; P. Terry O’Kane3; 1Lakefield ing to this study. 4. Impurity atoms in the molding compound may Research Limited, 185 Concession St., P.O. Box 4300, Lakefield, transport through the wire surface and reach the ball bond area causing Ontario K0L2H0 Canada; 2University of British Columbia, Dept. of corrosion or other degrading problems. Met. & Matls. Eng., 309-6350 Stores Rd., Vancouver, British Colum- 3 4:45 PM bia V6T1W5 Canada; O’Kane Consultants Inc., 502-455 Granville The Tin-Rich Corner of the Copper-Magnesium-Tin Phase Dia- St., Vancouver, British Columbia V6C1V2 Canada gram: Eduardo E. Vicente1; Alicia N. Alcaraz1; 1Comisión Nacional There are many examples of ores, concentrates and other materials de Energía Atómica, Matls. Dept., Av. del Libertador 8250, Buenos containing base metals (i.e. Cu,Ni,Co) as well as gold and platinum Aires 1429 Argentina group metals PGMs in which either the distribution of base metals and The copper-magnesium-tin ternary phase diagram was studied in PGMs is unfavorable, or their concentrations are too low, for these materials to be economically treated by conventional technology the region Sn-Cu6Sn5-CuMgSn-Mg2Sn. The employed experimental techniques were: optical microscopy, scanning electron microscopy, (matte smelting, acid pressure leaching, chlorination, etc.). A new X-ray diffraction, electron-probe microanalysis and differential ther- hydrometallurgical process has been developed for treating these feed mal analysis. A liquidus projection is proposed, which includes three materials, and will be described in this paper. The process has the invariant reactions: two ternary eutectics and a pseudobinary eutectic. potential to significantly improve the economics of treating feeds containing base metals and PGMs. The main feature of the process is 5:05 PM high temperature pressure leaching, under conditions that allow simul- The Tin-Rich Corner of the Copper-Tin-Zinc Phase Diagram: taneous and efficient (88 to 99%) dissolution of all the base metals and Alicia N. Alcaraz1; Eduardo E. Vicente1; Luis M. Gribaudo1; 1Comisión PGMs. Technology has also been developed to treat the product of the Nacional de Energía Atómica, Matls. Dept., Av. del Libertador 8250, leaching process and recover the base metals and PGMs as separate Buenos Aires 1429 Argentina saleable products. The copper-tin-zinc ternary phase diagram was studied in the region delimited by the tin corner and the 50 at%Sn isopleth. The 2:30 PM employed experimental techniques were: optical microscopy, scan- The Dissolution of Gold during the Pressure Leaching of Re- ning electron microscopy, X-ray diffraction, electron-probe microanaly- fractory Gold Ores in the Presence of Chloride: Michael J. 1 1 1 sis and differential thermal analysis. A liquidus projection and a subsolidus Nicol ; Jim Qing Liu ; Murdoch University, A J Parker CRC, South St., isothermal section are presented. Murdoch, Western Australia 6150 Australia Pressure oxidation is one of the preferred methods for the recovery of gold from refractory ores and concentrates. There have been several reports of the dissolution of gold during the acid pressure oxidation process and this has been attributed to the presence of chloride in the plant water or ore. This paper will describe the results of an electrochemical study of the behaviour of gold in acidic sulphate solutions containing varying amounts of chloride ions at high temperatures. It will be shown from both thermodynamic and kinetic studies that the oxidation of gold occurs as a result of the coupled anodic dissolution of the metal as the chlorocomplex ion with the cathodic reduction of ferric ions. Oxygen is not directly involved in the dissolution process. Conditions which will either minimise or maximise the dissolution of gold can be deduced from the thermodynamic and kinetic models.

48 3:00 PM 2:10 PM A Mineralogical Study of the Cyanide Leach Residues from Metallurgical P.E.; What Do I Do and Why?: Charles V. White1; Pressure-Oxidized Twin Creek Gold Ore: T. T. Chen1; J. E. 1Kettering University, I&MSE, 1700 W. Third Ave., Flint, MI 48504 Dutrizac1; G. L. Simmons2; 1CANMET, 555 Booth St., Ottawa K1A0G1 USA Canada; 2Newmont Mining Corporation, Englewood, CO 80112 USA A discussion of the mechanics of getting licensed, what’s on the Gold in the Twin Creek ore is primarily associated with arsenian exam, and why I need to do it? A review of the requirements to be pyrite. During pressure oxidation, the sulphides are solubilized, but licensed and the paper work needed and the timing will be covered. part of the dissolved iron reprecipitates as jarosite and as an iron Secondly, what’s on the exam (not a crib) but how the exam is pre- sulphate-arsenate-phosphate phase. The pressure oxidation products pared, what are the guidelines for the items and the test make up. are subjected to cyanide leaching. The cyanide leach residues consist of Lastly, why do I want to put myself through all this pain? What are quartz, gypsum, bassanite, anhydrite, small amounts of jarosite, an the issues with industrial employment vs. independent contractors and iron-sulphate-arsenate-phosphate phase, as well as trace amounts of how these issue effect you as a professional. orthoclase, rutile, pyrite, hematite and monazite; all these particles are dispersed in a fine grained matrix of illite-muscovite. The auto- 2:35 PM 1 clave leach residues contain a small amount of carbonaceous matter. Professional Registration: A Higher Standard: Christy Allen ;

1 PM MONDAY Many gold grains are detected on the surface of the carbon particles, Tennessee Department of Commerce and Insurance, Legal Sect., 312 and these gold particles are not leached during cyanidation. The gold 8th Ave. N., 25th Floor Tennessee Tower Bldg., Nashville, TN 37243 particles are typically 0.1-0.2 µm in size and commonly are embedded USA in the carbon surface or are coated with a K-Al-Si-S-O phase on the State registration boards exist to protect the health, safety and surface of the carbon. The gold grains are consistently associated with welfare of the public. Boards accomplish this mission by ensuring that elevated CI contents (50-300 ppm Cl), and the implication is that the only properly qualified people become registered as professional engi- gold was transported to the surface of the carbon as a gold neers and that, once registered, they provide professional services in a chlorocomplex. The poor gold cyanide leach recoveries, which ini- manner consistent with protection of the public. Professional engi- tially occurred in the Twin Creek developmental circuit under certain neers are held to high standards of practice and rules of professional operating conditions, are attributed to the presence of chloride in the conduct; they face disciplinary action if they fail to uphold those feed. This leads to the formation of soluble gold chlorocomplexes in standards. This program is a discussion of the ways in which the regu- the autoclave and the subsequent sequestering of the gold on the sur- lation of professional engineers, through the enforcement of rules of faces of the carbon particles. conduct, benefits professional engineers as well as the public. 3:30 PM Break 3:00 PM Break 3:45 PM 3:10 PM 1 Alkaline and Acid Autoclaves at Barrick Gold: Kenneth Glyndwr The Registered Engineer as an Expert Witness: J. Mike York ; 1 Thomas1; Richard Williams1; 1Barrick Gold Corporation, Operations York Engineering Services, 2107 N.W. Filmore Ave., Corvallis, OR Dept., 200 Bay St. P.O. Box 119, S. Tower Ste. 2700, Toronto, Ontario 97330 USA M5J 2J3 Canada The current environment for consulting engineers working as ex- This paper reviews the alkaline and acid gold autoclaving experi- pert witness is demanding. A 1993 Supreme Court decision has placed ences gained at Barrick Gold Corporation. Alkaline autoclaving was judges in the role of gate keepers to prevent “junk science” from being operational at Barrick Mercur, Utah, USA, on carbonaceous/sulphide presented to the juries. These requirements, in turn, place an increas- refractory ore for eight years commencing in 1988. Acid autoclaves ing burden on the expert witness to provide evidence as to their quali- have been operational at Barrick Goldstrike, Nevada, USA., on sul- fications to testify. Professional registration provides an excellent phide refractory ore since 1990 and now process 17,500 stpd of ore reference to establish the individual as having met the requirements of through six large autoclaves. Information is presented on operating knowledge in their designated field. Registration confirms the indi- costs, materials of construction, reagent requirements and flowsheet vidual has met peer reviewed examination in one or more jurisdiction, developments that reduced capital and operating costs. i.e. state(s), that extend well beyond academic institution or single organization. For engineers trying to break into the expert witness field, professional registration credentials must be substituted for court- room experience until that experience can be obtained. Professional registration is a key element in credential building for the aspiring Professional Registration expert witness. Sponsored by: TMS, Young Leaders Committee, Profes- 3:35 PM sional Registration Committee The Practice of Being a Professional Engineer: It’s More Than Program Organizers: Ned Bahtishi, Westinghouse Electric Just a Stamp: Larry M. Southwick1; 1L.M. Southwick & Associates, Company, Western Zirconium Plant, Ogden, UT 84404-9799 992 Marion Ave., Ste. 306, Cincinnati, OH 45229 USA USA; David Alven, GENCORP/AEROJET, Jonesborough, A professional engineer’s license is often required to certify the TN 37659 USA competence of a particular design or other document. These situations usually arise to fulfill certain legal requirements. However, many, probably even most, design and other engineering work do not require Monday PM Room: Bayou A formal certification, but they always require, and deserve, a competent March 13, 2000 Location: Opryland Convention Center effort. Here is where professional registration perhaps has its greatest value: as a sign of trust in the work being performed. Many engineering Session Chairs: Ned Bahtishi, Westinghouse Electric and operating companies require that the lead engineers be registered, again not necessarily to autograph documents, but more as an indica- Company, Commercial Nuclear Fuel, Ogden, UT 84404 USA; tion of overall confidence in the staff and its work. While obtaining an David A. Alven, GenCorp, Aerojet Ordnance, engineering registration requires only several years of practice and Jonesborough, TN 37659 USA satisfactorily passing a qualifying exam, certainly necessary and no mean achievements to be sure, practicing to that standard afterwards demands a continuing effort. This entails not only maintaining quality 2:00 PM Opening Comments work, but doing so with integrity and forthrightness. The presentation Dr. Patrick Taylor, Professional Registration Committee, Chairman will provide several examples of how being a professional engineer means more than just having a P.E. license stamp in one’s kit.

49 4:00 PM to the lack of translation symmetry for surface spins as well as from The P.E. License: Its Value in Industry: Nick Gianaris1; 1Visteon, the stray field of surface roughness. The second one comes from the an Enterprise of Ford Motor Company, Chassis Sys., 6100 Mercury

MONDAY PM demagnetizing field of close-to-surface layer with grad M. Both terms Dr., Dearborn, MI 48126 USA linearly decrease when temperature increased from 5 to 123K, but Engineering is a field whose practitioners have various educational dominant contribution is from the first component. The work was and experiential backgrounds in all industries and academe. Unlike partly supported by KBN Grant Nr 10.120.68. Literature [1] E.M. other professional fields such as medicine and law, an engineer is not Jackson, S.B. Lio, S.M. Bhagat and M.A. Manheimer, J. Magn. Magn. always required to be licensed to practice engineering in many indus- Mater. 80(1989) 229. [2] L.J. Maksymowicz, M. Lubecka and R. trial sectors. In this paper, the following will be presented: who is Jablonski J. Magn.Magn.Mater. 192 (1999). required to become licensed as an engineer today, why licensure in industry is significant for both the engineer and the company, personal 2:20 PM Laser Surface Modification of TiAl Intermetallics: S. A. experience in obtaining and using the P.E. license, and why the P.E. 1 1 1 1 license will become more important in the future. McElroy ; D. Yang ; R. G. Reddy ; University of Alabama, Metallu. and Matls. Eng., P.O. Box 870202, Tuscaloosa, AL 35487-0202 USA Surface modification of TiAl intermetallics was investigated using Nd-YAG pulse laser. Laser processed samples were characterized for their surface morphological and compositional changes using SEM, Surface Engineering in Materials XPS and X-ray diffraction. Large cracks along the grain boundaries Science I: Coatings/Films Synthesis and surface oxide layers in the laser processed samples were observed. Oxide layers consisted of Al2O3, TiO2, TiO and absorbed O2. Alumi- and Processes (SP)-II num enrichment in the oxidation layers of TiAl was observed. Sponsored by: Materials Processing and Manufacturing 2:40 PM Division, Surface Engineering Committee The Synthesis, Processing and Properties of Graded Thin Film/ Program Organizers: Sudipta Seal, University of Central Coating: John J. Moore1; 1Colorado School of Mines, Adv. Coat. and Florida, Advanced Materials Processing and Analysis Surf. Eng. Lab., Golden, CO 80401-1887 USA Center and Mechanical, Materials and Aerospace Engineer- The paper will discuss the design, processing and the resultant prop- ing, Orlando, FL 32816 USA; Narendra B. Dahotre, Univer- erties of graded coating systems that are needed to meet specific performance criteria. Three examples of graded coating systems will be sity of Tennessee Space Institute, Center for Laser Applica- used to demonstrate the philosophy used for coating systems for (a) tions, Tullahoma, TN 37388 USA; Brajendra Mishra, forming dies, (b) oxidation resistant coatings for Mo, and (c) glass Colorado School of Mines, Kroll Institute for Extractive molding dies, as used in the current research programs in the Advanced Metals, Golden, CO 80401-1887 USA; John Moore, Colo- Coatings and Surface Engineering Laboratory at the Colorado School rado School of Mines, Department of Metallurgy and of Mines. Materials Engineering, Golden, CO 80401 USA 3:00 PM Break 3:15 PM Monday PM Room: Canal B Indium Oxide Thin Film with a Large Surface Area: T. March 13, 2000 Location: Opryland Convention Center Pisarkiewicz1; T. Stapinski1; A. Sutor1; K. Zakrzewska1; 1University of Mining and Metallurgy, Dept. of Elect., Al. Mickiewicza 30, Krakow 30-059 Poland Session Chairs: Narendra B. Dahotre, University of Indium oxide (In2O3) is known as one of the gas sensing materials Tennessee Space Institute, Dept. of Matls. Sci. & Eng. Ctr. and then the films with a high surface-to-volume ratio are promising for Laser App., Tullahoma, TN 37388 USA; Enrique candidates for gas sensors. The authors deposited the films by rheotaxial Lavernia, University of California Irvine, Dept. of Chem. and growth and thermal oxidation (RGTO) technique. This technology is a Biochem. Eng. and Matls. Sci., Irvine, CA 92697-2575 USA two-step process in which the first step is the deposition of metallic indium onto substrates heated above the melting temperature of In and in the second step the metallic droplets are thermally oxidized in air 2:00 PM forming the polyctystallline film. Optical reflection with the help of Thin Films of Magnetic Semiconductors-Transport Phenom- hemispherical attachment were performed enabling determination of ena and Magnetic Properties: L. J. Maksymowicz1; M. Lubecka1; B. light scattering. Electrical transport (conductivity, Hall effect) mea- Cieciwa1; 1University of Mining and Metallurgy, Instit. of Elect., Al. sured in varying gas atmosphere and temperature indicate the essential Mickiewicza 30, Kraków 30-059 Poland role of thin film surface in the interaction of semiconductor with the Thin films of CdCr2Se4:In and CdCr2-2xIn2xSe4 were obtained by ambient gas. rf sputtering technique. We used the deposition device equipped with 3:35 PM three cathode system and rotatable substrate holder. As-deposited Si-N Coating by Plasma CVD Method: Y. Sato1; S. Ohtani1; N. samples are in amorphous state and have a form of multilayered struc- Iwamoto1; 1Ion Engineering Research Institute Corporation, 2-8-1, ture of Cr/Cd-Cr-In-Se/Cr. Heat treatment provides uniform polycrys- Tsuda-yamate, Hirakata, Osaka 573-0128 Japan talline single films with the required composition. The samples belong Si-N coating on steel by plasma CVD method was investigated to to the class of soft magnetic materials; CdCr2Se4:In has the reentrant improve mechanical properties as hard coating. Application of pulsed transition (REE), the energetic structure is modified diluting by In and DC was used for plasma formation. SiCl4 was used for silicon source. CdCr2-2xIn2xSe4 is in the spin glass state. Both types of samples Nitrogen gas and ammonia gas were used for nitrogen source and ef- have potential for use as photodetectors. The maximum of photocon- fects of gas species on properties of films was investigated. In the case ductivity is within the wavelength from 680nm to 840nm. It was of nitrogen gas coating, nitrogen contents in Si-N films were increased found that the maximum of voltage sensitivity is shifted towards the with the increment of pulsed DC power up to 30at% at 2.0kW. Nitro- infrared region when dilution levels are reduced. As far as the magnetic gen contents in films coated with ammonia gas were also increased properties are concerned, we are classifying the type of magnetic with the increment of DC power up to 50at%, which approached order by determination the temperature dependence of magnetization stoichiometry of stable silicon nitride. All of obtained Si-N coating (M) and unidirectional magnetic anisotropy field (Han) [1]. We have films were formed in amorphous structure. Si2p peaks at 99.5eV (Si-Si also determined the surface magnetic anisotropy energy constant ver- bond) and 101.6eV (Si-N bond) were appeared with 30at% nitrogen sus temperature. It was found that two components contribute to this containing films by XPS measurement. Coating with 50at% nitrogen constant [2]. One originates from the exchange interaction term due content showed only one peak at 101.6eV. These results show that 50 more Si-Si bond was included in low nitrogen containing film and high of the CIS thin film solar cell shows the crystalline and single phase nitrogen content film consist of Si-N bond. Hardness of Si-N film was orientation. The SEM analysis indicates well connected spherical grains changed with variation of applied DC power. The maximum hardness which are densely packed. The I-V characteristics of the films are of HV1800 was obtained at 0.5kW DC power. forward and reverse biasing is similar to the ideal diode. The open circuit voltage Voc and short circuit current density Jsc are respec- 3:55 PM tively 100 mV and 5 mA/cm2. The results are preliminary in nature Selective Area Laser Surface Alloying of Mild Steel with Car- and by optimizing the growth conditions further improvement in the bon: V. Sinha1; G. L. Goswami2; G. B. Kale2; I. Manna3; 1Ohio State results are expected. University, Dept. of Matls. Sci. and Eng., Columbus, OH 43210 USA; 2BARC, Atomic Fuels Div., Trombay, Mumbai 400085 India; 3I. I. T., Kharagpur, Dept. of Metallu. and Matls. Eng., Kharagpur, WB 721302 India Carburizing is an age old surface engineering technique to enhance Teaching Electronic, Magnetic and hardness and wear resistance of steel. However, carburizing exposes Optical Materials: A Symposium in the entire component to a complex heat treatment schedule and pos-

sesses several limitations in precision, energy/time economy and de- Memory of Professor Gregory E. PM MONDAY gree of improvement. The present study concerns laser surface alloy- Stillman: Session II ing (LSA) with a pre-deposited carbon coating for selective area hardening of steel components without affecting the entire bulk. Rectan- Sponsored by: Electronic, Magnetic & Photonic Materials gular specimens of 0.2% C steel were coated with 40 and 90 mm thick Division, Education Committee (d) carbon deposited by physical vapor deposition and irradiated with a Program Organizer: Mark A. Palmer, Virginia Common- 300 W Nd-YAG pulsed laser with output energy (E) = 6-12 J and pulsed wealth University, Richmond, VA 23284-3015 USA duration (t) = 8-14 ms, respectively. LSA with an optimum conditions develop a predominantly martensitic microstructure with a very high (750-1000 VHN) microhardness. However, an increase in d, t and/or E Monday PM Room: Bayou D leads to a higher w with a greater volume fraction of retained austenite March 13, 2000 Location: Opryland Convention Center in the microstructure and a lower hardness in the near surface region. Finally, an attempt has been made to correlate the microstructure, Session Chair: Mark A. Palmer, Virginia Commonwealth composition and hardness of the AZ with the LSA parameters. University, Richmond, VA 23284-3015 USA 4:15 PM Synthesis of Nanocrystalline Diamond Thin Films by Chemi- 2:00 PM Invited cal Vapor Depositions: D. Zhou1; A. Hussian1; L. Chow2; 1Univer- Linking Mathematics to Materials Science Through Interac- sity of Central Florida, Adv. Matls. Process. and Analy. Ctr., Dept. of tive Visualization: Shannon Pixley1; Krishna Rajan1; 1Rensselaer Mech., Matls., and Aero. Eng., Eng. 381, Orlando, FL 32816 USA; Polytechnic Institute, Depts. of Comp. Sci., Matls. Sci., and Eng., 2University of Central Florida, Dept. of Physics, Orlando, FL 32816 Troy, NY 12180-3590 USA USA A number of mathematical manipulation skills are needed in many Polycrystalline diamond films whose microstructures typically con- materials science courses. In this project, we are developing interac- sist of crystallites with sizes on the order of nanometers have been tive computer applets teaching linear algebra principles in the context successfully synthesized by a hot filament chemical vapor deposition of crystallographic applications. The modules are designed to provide (CVD) technique. Mixtures of methane, hydrogen, and argon were used a direct relationship between specific skill building exercises, such as as the reactant gases for the CVD processing, and the substrate (Si) matrix manipulation, to a materials science topic. A series of applets ° temperatures ranged from 450 to 800 C. X-ray diffraction, transmis- have been built permitting the student to visualize graphically the sion electron microscopy, and electron energy loss spectroscopy char- crystallographic perspectives of specific matrix operations. This acterizations show the films consist of a pure crystalline diamond project is part of a larger effort known as Project Links, providing phase with grain sizes ranging from 10 to 30 nm. Scanning electron teaching tools in mathematics for application in a variety of engineer- and atomic force microscopies analyses demonstrate that the surface ing subjects. of the nanocrystalline diamond films remain smooth and independent of the film thicknesses. The growth morphology of the diamond coat- 2:30 PM Invited ings, particularly the transition from microcrystalline to nanocrystalline Laboratory Experiences in Electronic Materials at the Univer- diamonds, has been discussed in the light of the functions of the atomic sity of Michigan: Rachel S. Goldman1; 1University of Michigan, hydrogen and the secondary nucleation, which are strongly affected by Dept. of Matls. Sci. and Eng., Ann Arbor, MI 48109-2136 USA the hot filament CVD processing parameters. Furthermore, the poten- We are developing a series of laboratory modules in electronic ma- tial applications of the nanocrystalline diamond thin films, such as terials and have started to incorporate these into our undergraduate electron field emitters, diffusion barriers, and protective coatings have curriculum at the University of Michigan. Example modules include: been addressed. (a) resistivity vs. temperature of metals, semiconductors, and insula- tors, (b) Hall effect measurements, (c) current-voltage measurements 4:35 PM of solar cells, (d) scanning tunneling microscopy, and (e) atomic force Preparation and Properties of Mo/CIS/CdS Thin Film Inter- microscopy. In this talk, I will discuss the new laboratory modules we faces for Photovoltaic Applications: S. R. Kumar1; 1National have begun to incorporate into our junior level laboratory courses. I Institute of Foundry and Forge Technology, Dept. of Matls. and Metallu. will also discuss some of our future plans which include the addition of Eng., Ranchi, Bihar 834 003 India magnetization and measurements of ferromagnetic materials. Copper indium selenide (CIS) thin film solar cells can be prepared by electrodeposition, dip coating and flash annealing at 400°C. The CIS 3:00 PM Invited thin films were prepared by single step electrodeposition process on Multidisciplinary Program in Sensor Materials and Devices: molybdenum substrate potentiostatically or galvanostatically. The as Sheikh Akbar1; Prabir Dutta1; Marc Madou1; Bruce Patton1; Yunzhi deposited films are crystalline and are preferably oriented along (112) Wang1; 1The Ohio State University, Ctr. for Indust. Sens. and Mea- direction have low resistivity which in turn is further reduced by an- sure., 291 Watts Hall, 2041 College Rd., Columbus, OH 43210 USA nealing in air. The cadmium sulphide films were prepared by dip coat- Under the umbrella of the NSF Center for Industrial Sensors and ing technique on glass, as well as on molybdenum and CIS thin film Measurement (CISM), a research and development program for harsh substrates. The as deposited films are highly resistive and oriented environment sensors is being actively pursued at Ohio State Univer- along (002) direction. The resistivity is considerably reduced and crys- sity. Research teams include students and faculty from Departments of tallinity increases by flash annealing at 500°C. The X-ray diffractogram Chemistry, Physics, Materials Science and Engineering, and Electrical, 51 Chemical and Mechanical Engineering. The CISM model has enriched 2:25 PM Invited engineering and physical science interdisciplinary education and has Thermal Spraying of Nano-Composite Coatings: E. J. Lavernia1; allowed us to develop a multidisciplinary industry-oriented curriculum R. Rodriguez1; M. Ice1; M. L. Lau1; 1University of California, Dept. of MONDAY PM that is currently being funded by the NSF-CRCD program and OSU Chem. and Biochem. Eng. and Matls. Sci., Irvine, CA 92697-2575 Honors House. Under this program, a new three-course sequence (9 USA credit hours) in sensor materials including instructional laboratories Recent advancements developed in the thermal spraying of with industrial experience is currently being developed. The courses nanocrystalline materials have attracted scientific and industrial inter- are being designed around the multidisciplinary approach of CISM, and est. Due to the relatively short dwell time of the powder particles are being team-taught by faculty members from a wide range of disci- during the thermal spray process and their inherent thermal stability, plines. These courses are targeted for senior undergraduate and begin- the feedstock powders are able to preserve the unique property of ning graduate students. The first course covering basic scientific prin- nanocrystalline materials in the as-sprayed coatings. The use of nano- ciples of sensor materials has already been offered once during the cermet powders such as WC-Co has produced coatings with increased Spring quarter of 1999. The second course will cover different sensor microhardness while maintaining toughness values as compared to applications and related technological issues. Both courses have a labo- conventional coatings. In the present study, nano-composite Al coat- ratory component. The third course will be group projects with par- ings were produced by plasma spraying. The feedstock nanocrystalline ticipating industries. Group projects will target specific industries, iden- powders were synthesized by mechanical milling of gas atomized 3003- tify a sensor need, develop a prototype and perform field-tests at the Al powders with the addition of 10 vol.% SiC in liquid nitrogen for 8 industrial site. Each project will be a team effort involving multiple hrs to produce agglomerates with increased surface area. The cryomilled students working in close collaboration with a faculty advisor and an powders were thermally sprayed by vacuum plasma spraying to pro- industry co-adviser. Students entering the courses will have the appro- duce Al-composite coatings. The residual stress of the nano-compos- priate background in science and engineering. Students taking this ite coating will be determined by X-ray diffraction analysis and com- sequence along with 11 credit hours of relevant courses in participat- pare to that of the conventional coating. The results will be rational- ing departments including Business and Law will have the option to ized based on the microstructural features observed in the transmission receive a minor or certificate degree in “Sensors and Measurements.” electron microscopy and scanning electron microscopy analyses. In addition, coating properties were characterized by microhardness and wear measurements performed on the coating cross sections and compared to those of the conventional Al-SiC coating. Ultrafine Grained Materials: Funda- 2:50 PM Invited mentals and Process Mechanisms: II A Cost-Effective Way to Make Nanostructured Carbides and Nitrides: Leon L. Shaw1; 1University of Connecticut, Dept. of Metallu. Sponsored by: Materials Processing and Manufacturing and Matls. Eng., Storrs, CT 06269 USA Division, Powder Metallurgy Committee, Shaping and The time and energy needed to make nanostructured or conven- Forming Committee tional carbide and nitride powders for sintered components, such as Program Organizers: Rajiv S. Mishra, University of valves, seals and bearings, could be cut to a fraction of what is now Missouri, Metallurgical Engineering, Rolla, MO 65409-0340 needed through a novel process developed recently at the University of Connecticut. The new process combines thermal and mechanical USA; S. L. Semiatin, Wright Laboratory, Materials Director- activation to enhance the reaction of compound formation. The basic ate, Dayton, OH 45440 USA; C. Suryanarayana, Colorado form of the new process is to mechanically activate the reactants at School of Mines, Department of Metal and Materials room temperature through high energy milling, followed by complet- Engineering, Golden, CO 80401 USA; Naresh Thadhani, ing the synthesis reaction at high temperatures. High energy milling at Georgia Institute of Technology, School of Materials room temperature has substantially increased the reactivity of the reactants and dramatically reduced the final reaction temperature and Science and Engineering, Atlanta, GA 30332-0245 USA time. The enhanced reaction has been attributed to the structural and energy state changes of the reactants caused by the mechanical treat- Monday PM Room: Polk A/B ment prior to the reaction. These structural and energy state changes March 13, 2000 Location: Opryland Convention Center contribute to the enhanced reduction through the increased reaction kinetics as well as the increased reaction driving force. Examples to illustrate these underlying mechanisms will be presented. Session Chair: C. Suryanarayana, Dept. of Metallu. and Matls. Eng., Golden, CO 80401 USA 3:15 PM Synthesis of Fe-TiN Composites by Thermal Plasma Process- ing: Sutham Niyomwas1; Banqiu Wu1; Ramana G. Reddy1; 1The Uni- 2:00 PM Invited versity of Alabama, Dept. of Metallu. and Matls. Eng., P.O. Box Role of Water in Energetics of Zeolites and Layered Materials: 870202, Tuscaloosa, AL 35487-0202 USA Alexandra Navrotsky1; 1University of California, Dept. of Chem. Eng. The Fe-TiN composite was synthesized in a non-transferred arc d.c. and Matls. Sci., Thermochemistry Facility, Davis, CA 95616 USA plasma reactor from ilmenite ore concentrate using methane and am- The UC Davis Thermochemistry Facility has been studying the monia as the reactive gases. The standard Gibbs energy minimization enthalpies of formation of zeolites, octahedral molecular sieves, and method was used to calculate the equilibrium composition of reaction layered materials by a combination of high temperature reaction calo- species. The products were characterized by X-ray diffraction and rimetric techniques. We find several common trends. Dehydrated SEM. Effect of plasma power, gas composition, ilmenite particle size, frameworks are metastable with respect to dense phases by 5-15 kJ/ feeding rate and particle injection position on purity of composite mol but hydrated frameworks are energetically stable by a similar were investigated. Experimental and theoretical results were discussed. amount (referred to liquid water and a 2-oxygen framework formula 3:35 PM unit). This energetic stabilization is counterbalanced by a negative Activated Sintering of Al TiO Nanoceramics: Joanna Groza1; entropy of hydration. The ∆H and ∆S terms scale with each other. 2 5 Vladimir Kodash1; Lia Stanciu2; Maria Zaharescu2; 1University of Cali- Thus the localization of water within the cage or layer is a major fornia, Chem. Eng. Matls. Sci., One Shields Ave., Davis, CA 95616 driving force in the formation of both framework and layered materi- USA; 2Institute of Physical Chemistry-Romanian Academy, Bucharest, als. New thermochemical data for a variety of zeolites and manganese Romania oxide based nanomaterials will be reviewed in the context of hydration The most critical stage in obtaining nanoceramics is sintering. Key energetics. to success is preserving the nanocrystalline size of starting powders in final consolidated ceramics. One way to achieve this objective is by sintering activation using an externally applied electrical field. The 52 essence of field activation is to enhance densification of ceramic pow- This paper presents work on the formation of metal matrix com- ders by decreasing the temperature and time of sintering, thereby posites formed from nanocrystalline TiC and Fe-Al. The nano-nano considerably suppressing the grain growth. Field activated sintering composite powder was produced by milling the commercially available technique (FAST) was applied to Al2TiO5 nanoceramics formed from pre-alloyed Fe-Al with ultrafine TiC powder. The high hardness and

BINARY Al2O3-TiO2 powders obtained by sol-gel method. It was found faceted nature of the TiC particles easily shears the Fe-Al powder that electric field activates formation of Al2TiO5 and its densification particles to an ultrafine size, resulting in the formation of a nano-nano in the temperature range 1050-1250°C. The influence of electric field powder mixture. The reduction in particle size of Fe-Al as a function

on Al2TiO5 formation, crystallization densification and final proper- of milling time and TiC content has been investigated, using XRD and ties will be presented. TEM. Consolidation of the powder mixtures to retain a nanoscale 3:55 PM Break structure in the composites is in progress. 4:05 PM Invited 5:30 PM Synthesis of Nanoparticles by a Novel Laser-Liquid-Solid In- Effect of Processing Parameters on Structure and Properties of 1 teraction Technique: J. Singh1; 1Pennsylvania State University, Nanocrystalline FeCrP Electrodeposits: C. T. Kunioshi ; L. V. 1 1 Appl. Rsch. Lab., University Park, PA 16804 USA Ramanathan ; Cidade Universitaria, Instit. de Pesquisas Engerget. e A novel laser-liquid-solid interaction (LLSI) technique has been Nucl., C.P. 11049, São Paulo 05422-970 Brazil PM MONDAY developed for synthesizing nanoparticles of materials including Ag, Some nanocrystalline alloys have shown superior corrosion resistance and can be used to protect other materials less resistant in ag- Ni, Ag-Ni alloy, SnO2, Cu from liquid precursors. Rotating niobium substrates immersed in the liquid precursor were irradiated by a con- gressive environments. Several techniques have been used to obtain λ nanocrystalline alloys and one of these is conventional electrodeposi- tinuous wave CO2 and Nd-YAG laser ( = 1064 nm). Size and morphology of nanoparticles was dependent on various process parameters tion. Fe-Cr-P alloy deposits were obtained from acid citrate baths including laser energy, wavelength, precursor chemistry and interac- using sodium hypophosphite as the source of P. The influence of tion time. Two-phase alloys containing silver and nickel were fabri- processing parameters such as nature of complexing agent, bath cur- cated by LLSI technique. The powders were characterized by x-ray rent density, bath temperature and use of ion selective membranes on diffraction (XRD), scanning electron microscopy (SEM), energy dis- deposit characteristics such as crystallite size, composition, and mor- persive spectroscopy (EDS) and high-resolution transmission electron phology were investigated. The corrosion behavior of steel substrates microscopy (HRTEM). The synthesis mechanism of non-equilibrium coated with nanocrystalline Fe-Cr-P deposits under specific plating Ag-Ni alloy nanoparticles has been proposed to occur primarily at the conditions was evaluated from potentiodynamic measurements in 0.05M laser-liquid-solid interface by a nucleation and growth mechanism. sulphuric acid and 0.1M sodium chloride. Nanocrystalline deposits with ~6-7% Cr and average crystallite size of 15 A were obtained 4:30 PM under a variety of plating conditions. Deposits obtained at ~100mAcm- Consolidation of Mechanically Alloyed Cu-In-Ga-Se Powders 2, in the presence of formic acid as complexant and after aging of the by a Field Activated Sintering Technique (Fast): C. Suryanarayana1; bath, were thick, homogeneous and adherent. The electrochemical J. Curtis2; J. R. Groza2; 1Colorado School of Mines, Dept. of Metallu. tests revealed increased corrosion resistance of the nanocrystalline and Matls. Eng., Golden, CO 80401 USA; 2University of California, deposit covered surfaces, as compared to the uncoated surfaces. Chem. Eng. and Matls. Sci., One Shields Ave., Davis, CA 95616 USA 5:50 PM Recently, copper indium diselenide (CuInSe2)-based photovoltaic solar cells have received considerable attention due to a high conver- Electron Beam Modification of Nanostructured Materials: Vadim 1 1 1 sion efficiency, up to 17.7% for a Cu-In-Ga-Se device. The present J. Jabotinski ; Francis H. (Sam) Froes ; University of Idaho, Instit. work presents an alternate processing route to the usually long deposi- for Matls. and Adv. Processes, Moscow, ID 83844-3026 USA tion methods. The new approach involves mechanical milling of el- Electron beam processing offers great technical and economic ca- emental powders followed by consolidation into bulk parts. Mechani- pabilities of improvement of nanostructured materials. Heating com- cal milling achieved powder blending and synthesis of the stoichiomet- bined with radiation treatment offering by the electron beam processing allows unique changes and modification in nanostructured materi- ric CuIn0.7Ga0.3Se2 compound. The mechanically milled powders were consolidated to a 5.51 g/cm3 density by a field assisted sintering tech- als. This paper will consider fundamentals and applications of the nique. The final grain size was in the nanometer range (~ 63 nm, as electron radiation in processing sintered powder components. The determined by XRD Warren-Averbach method). specific effects leading to increase in the component lifetime, wear, and heat resistance will be identified. Possible mechanisms for strength- 4:50 PM ening and improving the structure and creep performance will be dis- A Unified Viscoplastic Model for Densification of Powder Com- cussed. pacts: Hyoung Seop Kim1; Yuri Estrin2; Elazar Gutmanas3; 1Chungnam National University, Dept. of Metallu. Eng., Taejon 305-764 Korea; 2The University of Western Australia, Dept. of Mech. and Matls. Eng., Nedlands, WA 6907 Australia; 3Technion, Dept. of Matls. Eng., Haifa 32000 Israel A model for densification of metallic powders is proposed. It involves viscoplastic constitutive equations based on dislocation density evolution and also accounts for effects of porosity. The model was applied to the case of cold powder compaction under uniaxial compression conditions. Densification behaviour during powder compaction was simulated using a combination of the implicit and explicit integration methods as applied to the dislocation density evolution and the variation of the relative density of the compact, respectively. The model was gauged by comparing the experimental data generated by the cylindrical die compaction tests on Cu powder with the simulation results. 5:10 PM Synthesis of TiC/Fe-Al Nano-Nano Composites: E. G. Baburaj1; R. Fielding1; E. Nyberg2; F. H. (Sam) Froes1; 1University of Idaho, Instit. for Matls. and Adv. Process., 321 Mines Bldg., Moscow, ID 83844-3026 USA; 2Pacific Northwest National Laboratory, Battelle Blvd., P.O. Box 999, Richland, WA 99352 USA 53 54 Other March 12 - March 16, 2000 16, March 12 - March

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Opryland Convention Center Center Convention Opryland Daily Personal Schedule - Tuesday - March 14 March - Tuesday - Schedule Personal Daily

TUESDAY AM 55 susceptibilities are temperaturedependent(orconcentration depen- susceptibility of thematerialunderinvestigation andthefactthat exploiting amagneticbodyforce thatisdependentonthemagnetic or tofurtherstillconvectionin microgravity. Thisisachievedby that isintendedtoeliminateconvection inground-basedexperiments, experimental investigationwith associated mathematicalmodeling, have beencarriedoutwithNASA support.Thepaperdescribesan been successfulandseveralsolidification experimentsinEarthorbit eliminated, e.g.tostudysolidification inthediffusivelimit,havenot is wellknown.Ground-basedexperimentswheresuchconvection is Theroleofconvectionintransportingsoluteduringsolidification 2 Dept. ofMatls.Sci.andMineralEng.,Berkeley, CA94720USA; Chris Seybert plication ofaSusceptibilityDependentMagneticBodyForce Halting ConvectionduringSolidificationExperimentsbyAp- 8:50 AM USA R. A.Schiffman,R.S.ResearchInc.,CrystalLake,Barton,VT05822 8:30 AMWelcome andIntroductions ku, Sapporo062-8517Japan Industrial ResearchInstitute,MaterialsDivision,Toyohira- Session Chair: March 14,2000 Tuesday AM gna, DepartimentodiFisica,BolognaI-40126Italy Barton, VT05822USA;CarloPatuelli,UniversitadiBolo- Program Organizers: Committee Phases Committee,Thermodynamics&PhaseEquilibria Materials Division,StructuralAlloy Critical Technology Sector, Electronic,Magnetic&Photonic Sponsored by: Materials Science:Session1 Experimental MethodsforMicrogravity 12th InternationalSymposiumon Motorola Inc.,8000W. Sunrise,Plantation,FL33324USA Convention Center,PresidentialBallroom-JeffersonA "Bridging theGapBetweenTechnology Development Convention Center,PresidentialBallroom-AdamsA 1 ; J.W. Evans "Aspects ofTechnology Transfer" ASM International:MaterialsScience Hideki Minagawa,HokkaidoNational "Ancient ArtsofSwordMaking" & CommercialApplications" Convention Center,CanalB EPD DistinguishedLecturer Tutorial LuncheonLecture Location: OprylandConventionCenter Room: MemphisA 12:00noon-1:30pm Robert Schiffman,R.S.ResearchInc., Edward Dowling EPD Luncheon 1 ; W. K.Jones Daniel Eylon Derek Fray 12:00noon ✦✦✦ ✦✦✦ 1:45pm 2 ; 1 University ofCalifornia, TUESDAY AM : vary overarangeof10 gulfed ratherthanpushed,andforwhichcalculatedratesappearto term whichdescribesthefreezingrateaboveaparticleisen- erature havebeeninconclusiveastoestimatingthecriticalvelocity, a settling, andparticleclustering.Experimentalresultsgiveninthelit- processing isthelimitedabilitytocontrolparticlepushing, problems associatedwiththem.ThemainobstacletogoodMMC have significantindustrialpotential,howevertherearestillprocessing Particlereinforcedmetalmatrixcomposites(PRMMCs)appearto Eng., KingstonK7L3N6Canada Reginald W. Smith tion duringtheFreezingofReinforcedAluminumAlloys The InfluenceofGravityonParticlePushingandAgglomera- 9:10 AM Research supportedbyNASA. terms ofmathematicalmodelsforthemagneticfieldandflow. be availableatthetimeofconference.Resultsareinterpretedin ments withoutsolidificationbutsimilarresultswithshould precision ofthemeasurements.Initialresultshavebeenonexperi- current hasbeenidentifiedatwhichconvectionishalted,towithinthe position alittlebelowthemagneticcenterofmagnet.Aparticular at oneendandacoldtheother(thewallsbeingglass)was field strengthusingparticleimagevelocimetry. Acellwithahotwall Center tomeasurevelocitiesinconvectingsolutionsasafunctionof been conductedinasuperconductingmagnetatMarshallSpaceFlight on Earthbutsimplesolenoidsmaysufficeinspace.Experimentshave magnetic bodyforce.Sufficientfieldsrequiresuperconductingmagnets a concentrationchange)canbebalancedbyanoppositechangeinthe the reductioningravitationalbodyforceresultingfromexpansion(or dent inthecaseofsolutions).Inasufficientmagneticfield(gradient), of Berlin,Instit. of MetalsRsch.,Hardenbergstr. 36, PN2-3,Berlin Alloys intheStableandUndercooled Melt Thermodynamic Propertiesof BulkMetallicGlassForming 9:50 AM geneous nucleationbytheaddition oftheparticleswasconfirmed. alloy andthesamekindsofexperiments werecarriedout.Thehetero- experiments. ThefineparticlesofTiB2, TiCandSiCwereaddedinthe The resultshowedthehomogeneousnucleationwasattainedin the was comparedwiththoseobtainedfromtheclassicalnucleationtheory. relationship betweentheamorphousfractionanddropletdiameter determined fordropletswithincertaindiameterranges.Theobtained ing thecrystallizationheatofdropletsamorphousfractionswere Zr63Al10Ni11Cu16 alloywerecontainerlesslysolidified.Bymeasur- a shortdroptubefilledwithheliumgas,thesmalldroplets of Byejectingthemoltenalloyfromnozzleofasilicacrucibleinto ku, Tokyo 108-8548Japan 2 of Metallu.,7-3-1Hongo,Bunkyo-ku,Tokyo 113-8656 Japan; Tokumitsu ing aShort Drop Tube Containerless SolidificationofZr63Al10Ni11Cu16 AlloyUs- 9:30 AM selves andadvancingsolid/liquidinterface. for theinteractionofinclusionssuspendedinliquidwiththem- engulfment. Theseresultswillbediscussedinthelightofcurrenttheory were alsoexaminedandfoundtoincreasethecriticalvelocityfor became trappedbetweencellularprojections.TheeffectsofG-Jitter the pushingwasdonelaterallysothatreinforcementeventually growth conditionsexamined.However,duringcellulargrowth,mostof sec to100 ferent PRMMCsystemsprocessedatgrowthratesvaryingfrom1 the particlepushingexperiments.Thesamplesconsistedofthreedif- processing. Asemi-automatedfurnaceapparatuswasusedonMIRfor MIR inanattempttofurtherunderstandtheseproblemsPRMMC A seriesofexperimentswereperformedontheRussianSpaceStation -J. Fecht Shibaura InstituteofTechnology, Dept.ofMatls.Sci.,3-9-14,Minato- 2 ; D.S.Lee µ 1 ; KatuhisaNagayama m/sec. Someparticlepushingwasobservedunderallofthe 1 ; 3 ; S.Glade 1 Queen’s University, Dept.ofMatls.andMetallu. 4 whenappliedtotheAl+SiCparticlesystem. : Takahiro Suwa 3 ; W. L.Johnson 2 ; 1 The UniversityofTokyo, Dept. 1 ; Toshio Suzuki : 3 ; R. K.Wunderlich 1 Technical University 1 ; Kazuto 1 ; H. µ m/ :

TUESDAY AM 56 ; Daniel 1 Changxu ; 1 ; Baiyun Tong ; Kerry D. Moody 1 1 Popok Analytical Consulting & Popok Analytical Consulting 2 ; Langhong Lou K. M. Chang, West Virginia Univer- Virginia K. M. Chang, West 1 ; April M. Heaton 1 Room: Canal C Location: Opryland Convention Center David Furrer, Ladish Company, Cudahy, Ladish Company, David Furrer, Structural Materials Division, High Tem- Morgan Research Corporation, Matls. Sci., 2707 Artie St., Morgan Research Corporation, : Yaoxiao Zhu : Yaoxiao 1 Michael R. Fiske National Natural Science Foundation of China, 35 Huayuan ; 1 2 : ; 1 8:30 AM Invited Solidification of Su- Elements on Directional Effect of Trace peralloys Shi Beilu, E. Gate, Beijing 100083 China ele- of low segregation superalloy controlled by trace Technology ments was developed two decades ago at Institute of Metal Research in Advanced Technologies for Superalloy Advanced Technologies Technology Affordability Affordability: for Casting by: Sponsored perature Alloys Committee Organizers: Program Morgantown, Mechanical & Aerospace Engineering, sity, WV 26506 USA; K. R. Bain, GE Aircraft Engines, Cincinnati, WI Cudahy, Ladish Company, OH 45215 USA; D. Furrer, 53110 USA; S. K. Srivastava, Haynes International, Kokomo, IN 46904 USA Tuesday AM March 14, 2000 Session Chairs: WI 53110 USA; Gerhard Fuchs, University of Florida, Gainesville, FL 32611 USA Matls. Div., Processing Sci. and Tech. Brnch., M/S 105-1, Cleveland, M/S 105-1, Brnch., Tech. Sci. and Processing Div., Matls. USA OH 44135 interfa- solid/liquid measure the used to was Seebeck technique The The of Bi-lat%Sn. solidification during directional cial undercooling during microgravity conditions were conducted under measurements MEPHISTO Columbia using the flight of the space shuttle the STS-87 the Seebeck results show that The solidification facility. directional distance, velocity and growth not only on the interface signals depend The latter, behind the interface. the structure of the solid but also on the solidified to the translation of structural Seebeck, is due termed the gradient zone behind the interface. structure through the temperature contributions to the solidification measure- The structural Seebeck by the post-flight analysis of the space-grown ments were determined samples. AM 11:30 Fur- for Microgravity Technology A Unique Sample Quench naces Popok 35805 USA; Ste. 17, Huntsville, AL Homestead Rd., N.E., Huntsville, AL 35811 Engineering Inc., 6302 USA research programs require Microgravity Materials Science NASA’s analysis, evaluate rapid cooling of samples to enhance microstructural the geometry of the concentration/impurity profiles, and preserve of up to 100°C/sec is solid-liquid interface. A sample quench rate using traditional quench desired which has been shown to be unattainable (SACA) designs. systems and Sample Ampoule Cartridge Assembly I SBIR project aimed This paper will present the results of a Phase “Quench-in-Cartridge” specifically at solving this problem. A unique which the quench media (QIC) system has been designed for SACAs in is delivered internal to a (water and liquid gallium have been evaluated) reduces furnace design metallic containment cartridge. This concept of SACA design while complexity and allows it to be kept independent None of the existing or achieving significantly higher quench rates. incorporated in either planned quench system designs/methodologies simplicity and over- terrestrial or microgravity furnaces offer the whelming advantages provided by the QIC concept. ; ; 1 1 ; F. Cu- ; D. 5 1 1 NASA, Nb 2 57 Tadahiko ; Minoru 1 ; Tomihisa : 1 : Y. Lian : Y. and, Zr 8 data obtained by data obtained p ; Misako Uchida Ni 1 47 ; Kyoichi Kinoshita 1 Cu 11 ; F. D. Schowengerdt ; F. 1 Zr University of Florida, Matls. 1 ; Shinichi Yoda 34 systems has been studied with 1 x ; 2 , Ti 3 ; Naokiyo Koshikawa 1 California Institute of Technology, Institute California 3 Co 9 ; Yoshito Arai ; Yoshito ; Shuji Munejiri 1 1 ; J. J. Moore Ni 1 18 Cu and NiTi-TiB x 10 ; H. C. de Groh Al 1 X. Zhang 60 University of Ulm, Dept. of Eng., Albert-Einstein- Dept. of of Ulm, University : 2 ; Makoto Natsuisaka , Ti-TiB , Zr 1 3 National Space Development Agency of Japan, Tsukuba 10 1 Colorado School of Mines, Ctr. for Commercial App. of Colorado School of Mines, Ctr. O 1 2 ; Ni 1 ; Yasuhiro Nakamura ; Yasuhiro ; 1 7.5 1 C-Al ; Tomoharu Fukazawa ; Tomoharu ; Satoshi Matsumoto 4 Cu 1 1 R. Abbaschian have been investigated in the stable and undercooled melt in a and undercooled melt investigated in the stable have been 7.5 ; 10 1 Al Al 65 5.4 Chen USA; Gainesville, FL 32611 Box 116400, Sci. and Eng., P.O. Space Ctr., 2-1-1 Sengen, Tsukuba, Ibaraki 305-8505 Japan 2-1-1 Sengen, Tsukuba, Space Ctr., The measurement of diffusion coefficient of high temperature melts is one of the most important subjects for the utilization of microgravity environment. The shear cell is an advanced and capable method for the diffusion experiment. The shear cell for the high temperature melts was developed and tested due to the sounding rocket TR-IA 7th. The shear cell was applied to the diffusion experiment of molten Ag- Cu alloys and InGaAs semiconductors. The six furnaces were boarded couples were diffusion or five different on the sounding rocket. Ten contained within each furnace. The microgravity experiment was performed successfully in November 1998. The isotope diffusion and interdiffusion coefficient of molten Ag-Cu alloys were determined in the 6 different compositions at three different temperatures. Interdif- fusion coefficients of molten InGaAs semiconductor at three different temperatures were also determined. The correlation between the experimental results under microgravity and on ground is discussed. AM 11:10 using Seebeck Effect Measurements Interfacial Temperature of Bi-Sn Alloys Solidification during Directional Nakamura Kaneko respect to their sensitivity to the SHS reaction parameters of stoichi- respect to their sensitivity to the SHS reaction pressure, diluents and gasifying agents, ambient green density, ometry, porosity and me- microgravity in an effort to engineer the required to meet the require- chanical properties in these composite materials of bone replacement ments of a consumer, such as for the application expansion and the liquid materials. Gravity serves to restrict the gas it affects the microstruc- movement during SHS reaction, as a result, testing in KC135 ture and properties of the SHS products. Microgravity This paper will has extended the ability to form porous products. SHS process, the micro- emphasize the gravitational effects on the by comparing the structure and properties of those porous composites, microgravity (~Og), combustion synthesis of porous materials under normal gravity (1g), and higher gravity (~2g). 10:50 AM of Molten Eutectic The Measurement of Diffusion Coefficient Alloys by Using the Shear Cell under Microgravity Masaki Hirokazu Kato Itami Toshio Combustion in Space, Golden, CO 80401-1887 USA Combustion in Space, Golden, CO 80401-1887 synthesis (SHS) Combustion of self-propagating high-temperature of the B heating a glass prepared in earth laboratory by rapid quenching, the in earth laboratory by rapid quenching, heating a glass prepared a of these alloys have been evaluated over thermodynamic functions the allowing a systematic comparison of large range in temperature al- determining glass forming ability of these thermodynamic factors with results from ground based viscosity loys. These data are combined temperature-time-transformation curves with measurements to model Comparison with temperature- parameter. surface tension as a free measured in a electrostatic levitation de- time-transformation curves of of the interfacial tension and the influence vice allows estimates on the glass forming ability in these alloys. heterogeneous nucleants 10:10 AM Break 10:30 AM of Advanced Gravitational Effects on Combustion Synthesis Materials Porous Johnson P. Keck Lab. for Eng. Matls., 138-78, Pasadena, CA 91125 USA CA 138-78, Pasadena, Matls., Lab. for Eng. Keck alloys forming metallic glass of the properties thermophysical The Zr in the specimen were processed environment. The reduced gravity on board device TEMPUS containerless processing electromagnetic the method were performed by heat measurements spacelab. Specific c Combined with accalorimetry. of non contact 10623 Germany; Germany; 10623 1 Allee 47, Ulm 89081 Germany; Germany; 47, Ulm 89081 Allee

TUESDAY AM 57 A. Jackman ture. cation hasasignificanteffecton thefinalsolidificationmicrostruc- segregation. Itwasdemonstrated that grainmovementduringsolidifi- in termsofamountLavesphase, graindistributionandfinalmacro- cation ofINCONEL718.Theresults ofcalculationcanbepresented dendrites areconsidered.Themodelwasusedtocalculatethesolidifi- mity ofgrainsizeforeachcontrolvolume.Atthistimeonlyequiaxed growth. Adistributionfunctionisintroducedtohandlethenon-unifor- kinetics modelthatassumescontinuousnucleationandcalculatesgrain contraction. Themicro-transportmodeliscoupledtoasolidification transport calculation.Itconsidersthermosolutalflow, solidification microstructure ofalloys.Thecontinuummodelisusedinthemacro- of grainmovementonthemicrostructureevolutionandfinal Anexistingmodelwasfurtherdevelopedtoaccountfortheeffect P.O. Box870202,Tuscaloosa, AL35487USA Yang ture EvolutionduringSolidificationofSuperalloyIN718 Modeling ofGrainMovementanditsInfluenceonMicrostruc- 9:45 AM Processing Consortium. Energy undercontractDE-AC04-94AL85000,theSpecialtyMetals be discussed.ThisworkwassupportedbytheU.S.Departmentof conditions, andthemechanismsbywhichsegregationoccurswill resolution. ThenatureofNbsegregation,itsrelationshiptomelting total ingotcrosssection,aswellinisolatedregionsathigherspatial ray fluorescencetechniquestogeneratecompositionmapsoverthe been longitudinallysectionedandcompositionallyanalyzedusingx- been meltedoverawiderangeofprocessingparameters.Ingotshave stand thesegregationofNbandformationdefects,ingotshave gots aremeltedundercloselycontrolledconditions.To betterunder- Nb containingmacrosegregationdefectscanonlybemetiflargein- Alloy 718.ThetightcommercialspecificationsonNbcontent,and SegregationofNbcanbeamajorissueinhighqualityrotatinggrade 9402, Livermore,CA94550USA J. VanDenAvyle Niobium Segregation in718VAR Ingots 9:20 AMInvited larger partswiththeconventionalandlowcostcast-wroughtapproach. superalloys, ithasbeenpossibletomeettoday’s requirementsfor part. Withcontinuingimprovementsinthetechnologyofmelting This isnotpossibleforverylargepartswheretheentireingotone inspection andselectiveremovalofsuchdefectsatthebilletstage. nents, madefromsmalldiameterforgedbillet,allowforanin-process detected asultrasonicindicationsinfinishedforgings.Smallercompo- white spotsandoxide-nitrideinclusions.Manyofthesedefectsmaybe can resultfromthemeltingprocess.Theseincludefreckles,dirty for severalsuperalloyswithreferencetometallurgicaldefects,which loy components.Processingandcurrentsizecapabilitiesarereviewed base powergeneration.Thishasledtothedemandforlargersuperal- and operatingtemperatureofturbineenginesforbothaircraftland Inrecentyears,therehasbeenaverysubstantialincreaseinthesize USA Allegheny Teledyne Co.,2020AshcraftAve., Monroe,NC28110 Large DiameterSuperalloyIngots 8:55 AMInvited Hf. Experimentalfactswithexplanationwillbepresented. can beimprovedwithlowsegregationtechnologywithoutadditionof elevated temperatures.(4)ThepropertiesofDSsuperalloyRene’125 tional solidificationwithpronouncedimprovementofpropertiesat segregation technologycanmakemoresuperalloyssuitablefordirec- properties hasbeendevelopedbylowsegregationtechnology. (3)Low superalloy thatcansubstitutecobaltbaseX-40withsuperion higher thenconventionalonesatsimilarcomposition.(2)Nickelbase effective inthefollowingway. (1)Newalloyscouldbeused20-25 Low segregationtechnologyusedforsuperalloydevelopmentisvery China. Theprincipleandexperimentaleffectswillbedescribed. 1 ; D.M.Stefanescu 1 ; A.StewartBallantyne 1 ; 1 Sandia NationalLaboratories,P.O. Box 969,MS 1 ; 1 The UniversityofAlabama,Solid.Lab., : 1 ; BetsyJ.Bond Richard L.Kennedy : J. Brooks 1 ; 1 ; J.Krafcik 1 1 Allvac, An ; Laurence : B. J. ° C 1 ; Superalloys The HotDeformationModelingofAs-CastHigh-Strengthened 10:50 AM influences solidification. discussed withrespecttothepossiblemechanismsbywhichcarbon DTA foralarge setofalloys.Theresultstheseexperimentswillbe carbides hasbeenstudiedviasegregationmeasurementscoupledwith the defectgeneratingmechanismsarenotwellunderstood.Theroleof precipitation ofMCcarbides,theinteractionsthesecarbideswith of graindefects.Whileitisknownthatcarbonadditionsresultinthe (up to0.1wt.%)haveastrongbeneficialeffectinreducingthenumber mechanism(s) whichleadtograindefectformation.Carbonadditions investigate therelationshipbetweenalloychemistryand problem. Recentsolidificationexperimentshavebeenconductedto during directionalsolidificationhasbecomeanincreasinglyimportant to improvehigh-temperaturecreepproperties,graindefectformation loys. Aslevelsofrefractoryalloyingadditionshavegraduallyincreased development ofmulti-componentsinglecrystalnickel-basesuperal- Demandsforincreasedefficiencyinturbineengineshaveledtothe Engines, OneNeumannWay, Cincinnati,OH45215USA Glow PlasmaSurfaceAlloying A NewTechnology ofSuperalloySurfaceMetallurgy–Double 11:10 AM ena occurringduringthehotdeformation. experimental resultsaccuratelybutalsoreflectthephysicalphenom- eters wasalsobuiltup.Generally, theseequationsnotonlyfittothe relationship betweendeformationductilityandparam- hot deformationparameterswerebuiltup.Second,themathematical stress anddeformationparameters,especiallythepeakflowvs on thetestresults.First,mathematicalrelationshipbetweenflow were examined,andthehotdeformationmodelingwasbuiltupbased deformation behavior. Inthispaper, thehotdeformationbehaviors worthy todevelopaeffectivehotdeformationmodelingpredictthe steps mustbetakentogetsuitableprocessingparameters,so,itisvery ventional manufacturingroutes,agreatamountsoftrial-and-error deformation parametersisverydifficultandimportant.Inthecon- available deformationtemperaturerange.So,thecontrollingofhot cause oftheirhighflowstress,lowdeformationductilityandnarrow Thehigh-strengthenedsuperalloyshaveharshhotworkabilitybe- 100081 PRC Dept. ofSuperalloys,76XueyuanNanRd.,HaidianDistrict,Beijing Forbes Ave., Pittsburgh, PA 15213USA; fied Nickel-BaseSuperalloys Carbides andGrainDefectFormationinDirectionallySolidi- 10:25 AM 10:10 AMBreak and oneorderofmagnitudelower than thatofAISI304stainlesssteel. layer onpureironareequaltothat ofnickel-basesuperalloyInconel625 20%HCl solutionshowthatthe corrosion ratesofsurfacealloying local chemicalcomposition.The corrosiontestsin20%H2SO4and layers consistofmatrixandseveralprecipitateswhichdependson the ers wereanalyzedbySEM,EDAXandXRDshowthatthealloying DGPSA. Thechemicalcompositionandmicrostructureofsurfacelay- steels (lowcarbonsteel,pureironandstainlesssteel304)byusing base superalloyInconel625isobtainedonthesurfaceofthreekind rial surfaces.Inthispaperthesurfacealloyinglayersimilartonickel- ing layerswithspecialpropertiescanbeformedonthecommonmate- Kingdom, UnitedStatesandsoon.Thepremiumqualityplasmaalloy- China byZhongXuandpatentedinChina,Canada,Japan,United an advancednewsurfacemetallurgy technology. Itwasinventedin TheDoubleGlowPlasmaSurfaceAlloyingTechnology (DGPSA)is University ofTechnology, Taiyuan 030024China Matls. Sci.andEng.,30XueyuanLu,Beijing100083China; Dong Lin Murphy 1 ; 1 Zengyong Zhong ; ZhongXu 2 ; 1 Carnegie MellonUniversity, Matls.Sci.andEng.,5000 : Zhengdong Long 2 ; 1 University ofScienceandTechnology, Dept.of 1 ; 1 Central Iron&SteelResearchInstitute, : 1 ; JingyunZhuang Sammy Tin : Xishan Xie 2 General ElectricAircraft 1 ; Tresa Pollock 1 ; XuZhang 1 ; BoDeng 1 1 ; Jianxin ; Wendy 2 Taiyuan 1 ; Ping

TUESDAY AM 58 ; ; 1 1 : Hongmin Jomar Thonstad Xiangwen Wang : : University of Applied 3 Norwegian University of Science 1 ; 3 Massachusetts Institute of Technology, 1 ; 1 Smelter Technology Laboratory, Corp. Rsrch. Corp. Laboratory, Smelter Technology 1 ; ; Helmut Vogt 1 2 University of Toronto, Dept. of Matls. Sci., 184 Col- University of Toronto, 2 Donald R. Sadoway ; 1 & Technology, Dept. of Matls. Tech. & Electrochem., Trondheim & Electrochem., of Matls. Tech. Dept. & Technology, 7491 Norway; Ontario M5S3E4 Canada; lege St., Toronto, Rm. 8-109, Cam- Dept. Matls. Sci. and Eng., 77 Massachusetts Ave., bridge, MA 02139-4307 USA The electrode reactions occurring on carbon anodes during the electrolytic production of aluminum are being studied in a laboratory-scale cell. Electroanalytical techniques such as voltammetry and electrochemical impedance spectroscopy are being used to determine the mechanisms associated with the electrochemical reactions at the anode. The work is motivated by the belief that an understanding of the elementary reactions occurring under a variety of process conditions will enable the development of strategies for reducing the intensity of perfluorocarbon (PFC) emission. The research is sponsored jointly by the Aluminum Association and the U.S. Environmental Protection Agency. have also been studied and it has been found these differences have a differences found these has been and it been studied have also cell conditions. individual effect on the direct AM 9:25 and of Anode Overvoltage Anodic Phenomena–Observations Electrolysis during Aluminium Gas Bubbling Tabereaux Alton T. AL Second St., Muscle Shoals, Metals Co., 4276 Reynolds and Dev., USA 35661-1625 (gas bub- formation-release process and the gas Anode overvoltage anodic phenomena during the electrolytic bling) are two important in Hall cells. Comprehensive electrolysis studies production of aluminum of these anodic phenomena including bubble and physical modeling observations, overvoltage, and their relations formation and release have been reported in the literature. to anode size and configuration studies have been conducted mainly with two But, these anode bubbling in 1) extremely small (low amperage) anodes extreme anode scales; industrial (high amperage) anodes in produc- laboratory cells 2) large an on electrolysis studies conducted with tion cells. This paper reports to cm diameter) anode in a laboratory cell intermediate scale (15.2 data and explanations to bridge the results ob- provide experimental using the two extreme anode scale cases tained from previous studies Information on bubble size and the formation- with bubble formation. the bubble formation- release processes were obtained by measuring magnitude from bubble release process frequency as well as the voltage during a continuous 72 growth, coalescence and release from the anode on increasing the cell electrolysis test. The impact of gas bubbles phenomena as a func- resistance, the anode overvoltage and gas bubble were observed and re- tion of anode consumption (shape change) in anode current density was investigated. The recorded. Variation relationship between bub- sults provide an insight in understanding the during aluminium bling phenomena and anode overvoltage variations production. 9:50 AM On the Anode Effect in Aluminium Electrolysis A. Utigard Torstein Sciences, Berlin D-133353 Germany result in reduced energy Anode effects are detrimental in that they C2F6. With prospects of efficiency and cause emissions of CF4 and gases may be- future CO2, taxes, the emissions of these greenhouse US$ per tonne, each anode effect a CO2 tax of 15 With come costly. cost by about minute per day per cell will increase the production has been reviewed and 1.2%. Research work related to anode effects effects occur when the analyzed. Although it is well known that anode normal electrolysis, the alumina content becomes too low to maintain mechanism of the initiation of the anode effect as well as the current distribution and gas behavior in industrial cells are still not fully understood. The paper concludes by analyzing various methods which may be used to decrease the frequency and duration of anode effects in prebake as well as Soderberg cells. 10:15 AM Break 10:25 AM An Electroanalytical Study of Electrode Reactions on Carbon Anodes during Electrolytic Production of Aluminium Zhu : The 1 Ladish ; 1 2 ; 1 Aluminium 1 ; 1 ; D. Furrer 1 ; Tony D. Ackland Tony ; 1 ; B. Zirbel ; Michel Reverdy 1 1 John Chen, University of Auckland, New Zealand Aluminium Smelters Limited, ; Barry J. Welch ; H. Waldal 2 1 1 Room: Sewanee Location: Opryland Convention Center Bernd Rolofs, Hoogovens Aluminium Light Metals Division, Aluminum Committee T. Reay T. : ; Jean-Michel Peyneau 1 M. Derek Gadd M. Derek : Tech. Dev., Private Bag 90110, Invercargill, New Zealand Invercargill, Private Bag 90110, Dev., Tech. With modern smelting cells operating to a fine heat balance the impact of various operating and cell condition changes on the heat A study of the changes in balance needs to be examined more closely. top heat losses has been made by monitoring duct gas flow rate, duct gas and hood temperatures while regularly measuring ambient air and electrolyte temperature. With a continuous recording of cell process event messages, correlations between heat loss and the various routine operations and process changes have been possible. Particular attention has been placed on anode changing, metal tapping, alumina feeding and cell anode effects. The differences between individual cells University of Auckland, Chem. and Matls. Eng., Private Bag 92019, Auckland New Zealand; Pechiney, LRF-BP 114, Saint-Jean-de Maurienne 73303 France 114, LRF-BP Pechiney, enabled the control of Hardware and software developments have last two decades. Pro- reduction cells to evolve dramatically over the as well as the technical cess computers allow the control of cells of cell automatic management of modern potlines. The objectives encompass alumina feed- process control are reviewed. They normally and cell heat balance ing, cell resistance regulation and bath chemistry Tools control. Routine operations on the cells are also accounted for. are made available to assist potline supervisors in the optimization of operations, quick diagnosis of process changes, correction of abnormal and exceptional situations on individual cells or potlines as well as scheduling of work on the cells. New developments in cell and potline control provided by the ALPSYS system are presented. 9:00 AM Heat Operations on Smelter Cell Top The Effects of Process Losses 8:30 AM Invited Cells and Potlines Overview of Process Control in Reduction March 14, 2000 Session Chair: D-46549 Germany Huttenwerk GmbH, Voerde Pierre Homsi Tuesday AM Aluminum Reduction Technology: Aluminum Reduction Phenomena Process Control/Anodic Sponsored by: Program Organizers: Auckland Department of Chemical & Materials Engineering, J. Kipouros, Dalhousie University, New Zealand; Georges Engineering, Department of Mining and Metallurgical Halifax, NS B3J2X4 Canada Company Inc., P.O. Box 8902, 5481 S. Packard Ave., Cudahy, WI Cudahy, Ave., 5481 S. Packard 8902, Box Inc., P.O. Company USA 53110-8902 design require- are key factors for level and flaw content Quality engine manu- for aircraft turbine component lifting issues ments and used for many superalloys are and wrought nickel-base facturers. Cast low and high engines, such as the applications in turbine demanding is of of these critical components disks. Inspection pressure turbine a An effort has been undertaken to develop significant importance. inspecting cast and wrought superalloy ma- new method of ultrasonic the complete assessment of input material in terial to allow for a more value-added operations being performed. billet stage prior to extensive be ultrasonic inspection has proven to The utilization of multizone for improving ultrasonic inspection of cast effective and beneficial billet material. and wrought superalloy 11:30 AM 11:30 Superalloy Metallurgy of Ingot Inspection Sonic Multizone Material Billet

TUESDAY AM 59 Lorentz PetterLossius elimination ofreinforcement partsandthestamping diesusedtomanu- exact needsofa specificpart.Costsavingscan begainedbythe cess. Thisenables thedesignengineerto“tailor” blanktomeetthe and/or propertiesjoinedtogether through sometypeofweldingpro- These blanksconsistoftwoormore sheetsofdissimilarthicknesses can besavedinaluminumstructures withtheuseoftailoredblanks. existing manufacturingprocesses.As insteelstructures,costandweight crease theweightofvehiclebody structures andisalsoconsistentwith body structures.Aluminumisone suchmaterialthatcangreatlyde- auto industrytolookalternativematerialsthansteelforvehicle Thepushtomanufacturelighter-weightvehicleshasforced the Sys. Eng.,2300Eng.Complex,Dearborn,MI48128USA USA; Sys. Dept.,P.O. Box2053,MD3135/SRL,Dearborn,MI48121-2053 P. A.Friedman Aluminum Tailor-Welded BlanksforAutomotive Applications 8:30 AM USA Sherman, FordMotorCompany, Dearborn,MI 48121-2053 College ofEng.,Lexington,KY40232USA;AndyM. Session Chairs: Room: Knoxv March 14,2000 Tuesday AM Technology, Lexington,KY40506-0043USA Kentucky CollegeofEngineering,CenterforAluminum Program Organizer: Sponsored by: Automotive Alloys2000:Applied control system. implementing, replacing,expandingorrevampingthereductionline parison isthenpresented,providingavaluabledecisiontoolwhen some architecturesarediscussed.Aframeworkfortopologiescom- tributed automationtopologiesaredescribed.Theprosandconsfor and resultstoimplementcentralized,semi-distributedtotallydis- aluminium reductionlinecontrolsystems.Theconcepts,approach, Thispaperanalyzesthedifferentdegreesofdistributionadoptedby Pernambuco 353,BeloHorizonte,MinasGerais30130-150Brazil Trigueiro Carsten M.Ritter Distribution AspectsinReductionLineControlSystems 11:15 AM feedback toimprovethenextround. served. Aftereachroundrobintheresultsareanalysedandusedas ins areconductedannuallytoensurethattheharmonisationispre- 0.45wt% dependingonequipmentandmethods.Atpresentroundrob- tribute toarealstandarddeviationinthereportedresultsof0.20 precision canbelessthanO.O5wt%,otherstepsintheanalysiscon- participating laboratories.Itisshownthat,althoughtheinstrument reported resultsandtheeffectofusingdifferentequipmentin vidual stepsintheanalysiscontributetostandarddeviation standards areaddressed.Thepresentationalsooutlineshowtheindi- bath standards,andsomeproblemsconnectedwiththeaccuracyof critical stepsidentified.Themostcomplexpartwasestablishingnew sampling toinstrumentcalibrationandanalysiswasscrutinisedthe acidity inHydroAluminiumMetalProducts(HAMP).Eachstepfrom This presentationdescribestheharmonisationofanalysisbath plants itisimportanttoensurethattheresultsreallyarecomparable. Whencomparingprocessdatafromdifferentaluminiumreduction 303, Ovre-ArdalN-6881Norway Foosnaes Analysis ofExcessAlF 10:50 AM 2 University ofMichigan-Dearborn,Dept.Indust.andManufact. 1 ; 1 ; 1 Hydro AluminiumTechnology CentreArdal,P.O. Box 1 ATAN AutomationSystems,AluminiumDiv., Rua 1 ; G.T. Kridli Light MetalsDivision,AluminumCommittee 1 ; LuizF. R.Neves Subodh K.Das,UniversityofKentucky, 1 ; HelgeHoie Location: OprylandConventionCenter Subodh K.Das,Universityof 3 -Harmonization inHydroAluminium 2 ; 1 Ford ResearchLaboratory, Manufact. 1 ; HanneHoelPedersen 1 ; LeonelV. M.Ivo ille A 1 ; JoséH.S. 1 ; Trygve : : : Hall, 5000ForbesAve., Pittsburgh, PA 15213-3890USA; 1 the DisorientationCorrelationFunction Alloy SheetanditsRelationtoMicrostructureAnalyzedwith Surface RoughnessDevelopmentin6022and6016Aluminum 8:50 AM these blanksforautomotiveapplications. ability oftheseblanksisdiscussedaswelltheoverallpotential conventional steelTWB.Theeffectofgaugemismatchontheform- aluminum alloyswereanalyzedandcomparedwiththoseofamore aspects ofTWBsmanufacturedfrom6111-T4,5754-Oand5182-O fore haveagreatertendencytofailintheweld.Inthisstudy, several minum TWBsdonotexperiencethisincreaseinstrengthandthere- material whichhelpspreventfailureintheweldduringforming.Alu- welding ofsteelTWBstendstoincreasethestrengthweld ability ascomparedwithtypicaldrawing-qualitysteels.Additionally, This problemismoresevereinaluminumbecauseofitslimitedform- ness differentialinTWBscanoftenresultdifficultystamping. potential weightandcostbenefits,thecontinuousweld-linethick- fore canallowfordown-gaugingofparts.WhileTWBsofferboth one thickerpieceismoreefficientthanaweldedstructureandthere- facture them.Weight savingscanbeattainedbasedonthefactthat be lesssusceptible toSCCasaresultoflimitingbeta phase(Al8Mg5) tions ofelements thatproduceaprecipitatemicrostructure thatmay 5083 composition willbeevaluated.Emphasis beplacedonaddi- ary regions.Theprecipitationbehavior ofvariousalloyswithnear- enrichment andsubsequentMg-based phaseformationingrainbound- out asthemostsusceptiblestress corrosion crackingasaresultofMg levels ofMghigherthanabout3.5 wt%havebeenspecificallysingled phase) alonggrainboundaries.The alloysofthisseriesthatcontain (SCC) hasbeenlargelyattributed totheprecipitationofMg(beta Thesusceptibilityof5000seriesalloystostresscorrosioncracking Box 98,Ravenswood,WV26164USA USA; Sci. andEng.,477Watts Hall,2041CollegeRd.,Columbus,OH43201 Mills fied 5083AluminumAlloys Precipitation BehaviorinGrainBoundaryRegionsofModi- 9:10 AM FG02-96ER45601. Energy Research,USDepartmentofundergrantnumberDE- rolling direction.ThisworkwasprimarilysupportedbytheOffice of direction, thefracturepathbecomesparalleltoridges,i.e. the that, whenthetensileaxisiswithinafewdegreesoftransverse the Hilltheoryasanglefromrollingdirectionincreasesexcept esting resultofthesheettensiletestsisthatfractureanglefollows phenomenon, theDCFrevealsacomplexbandedstructure.Aninter- mation ofsheets.Insamples6016treatedtodeveloptheridging correlation mayhaveimplicationsforstrainlocalizationinthedefor- roughening tendencies.Theseobservationsoflongrangeorientation stronger texturecorrelationsareobservedinmaterialswithgreater sheets withdifferentsurfacerougheningsusceptibilitiessuggestedthat with surfaceridging,similarspacingsarefound.Also,acomparisonof other direction.WhenbandsobservedintheDCFmapsarecompared along theextensiondirectionaremorehighlycorrelatedthaninany function ofstrainlevel.Atlargestrains,forexample,grainslying grain diameters.SubstantialchangesintheDCFareobservedasa long-range orientationcorrelationsextendingovermorethanfive tion ofdistanceanddirection.Theresultsindicatethepresence been used.TheDCFcalculatestheaveragemisorientationasafunc- ventional images,thedisorientationcorrelationfunction(DCF)has ities andcorrelationsintexturethatarenotreadilyapparentcon- formed inplanestraintension.Inordertoquantifyheterogene- through samplesof6022and6016,bothintheT4condition,de- orientation imagingmicroscopyhasbeenusedtocharacterizesections Taking thecrystallographicnatureofslipasabasisforinvestigation, crease theusefulnessofformedpartorevenlimitformability. face roughnessasplasticstrainaccumulates.Suchmayde- Animportantaspectofsheetformingisthedevelopmentsur- cal Center, PA 15069USA Young University, Dept.Mech.Eng.,Provo,UTUSA; Paul S.Lee Carnegie MellonUniversity, Dept.Matls.Sci.&Eng.,3327Wean 1 ; G.S.Daehn 2 Century AluminumCorporation,RavenswoodOperations,P.O. 1 ; BrentL.Adams 1 ; B.R.Dunbar : 2 ; HenryR.Piehler M. C.Carroll 2 ; 1 The OhioStateUniversity, Matls. : 1 ; P. I.Gouma Anthony D.Rollett 1 ; HassoWeiland 3 Alcoa Techni- 2 Brigham 1 ; M.J. 1 3 ; ;

TUESDAY AM 60 ; 1 Ford John 2 : Ford Motor 1 ; 1 ; Peter A. Fried- 1 ; Richard William Davies ; Richard William 1 ; John E. Allison 2 University of Illinois, Mech. and 2 ; Armand J. Beaudoin ; Armand J. 1 Battelle PNNL, Matls. Processing, 902 1 ; 1 Mark Tower Smith Mark Tower Karole J. Lian ; Huseyin Sehitoglu 1 : : University of Illinois at Urbana-Champaign, Dept. of Mech. of Illinois at Urbana-Champaign, University 1 ; 2 Company, Matl. Sci. Dept., Scientific Rsch. Lab., MD 3182 SRL, Company, Dearborn, MI 48121-2053 USA; Battelle Blvd., P.O. Box 999 MSIN:P8-35, Richland, WA 99352 USA 99352 Box 999 MSIN:P8-35, Richland, WA Battelle Blvd., P.O. is receiving sig- Tubular hydroforming of automotive components capable of reducing part nificant attention as a manufacturing method costs. Hydro- count, component weight, and overall manufacturing produce complex shaped forming is extremely attractive as a method to materials. U.S. automo- components from tradition tube and extrusion many steel tive companies and suppliers are currently manufacturing aluminum al- tubular hydroformed components. However introducing with the current auto- loys to hydroforming applications is consistent to reduce the overall motive company and government initiatives work evaluates and weight and emissions of automobiles. The current during hydroforming ap- presents the formability of aluminum alloys vary the applications, including studies conducted to systematically plication of axial end feed and internal pressure during the hydroforming experiments. The current work also experimentally investigates the anisotropic yield locus of the extruded aluminum tubing, and theoretically evaluates the effects the manufacturing inherent anisotropy has on the formability of aluminum alloys extrusions. AM 11:00 Thermo-Mechanical Fatigue of a Cast 319 Aluminum Lasecki Victor Industrial Eng., 144 Mech. Eng. Bldg., 1206 W. Green St., Urbana, IL Industrial Eng., 144 Mech. Eng. Bldg., 1206 W. 61801 USA The majority of automotive engine cylinder heads are cast aluminum. The trend is for aluminum cylinder heads to be used in increasingly more demanding operational environments which necessitates a knowledge of the material behavior under cyclic thermo-mechanical loading conditions. The purpose of this study is to determine the extent to which existing constitutive and life models can be extended to loading situations in which the strains are predominantly compressive. TMF experiments were carried out under mechanical strain control on solid cylindrical specimens of 319 Al. The TMF cycle was selected so as to simulate the critical conditions that exist in the surface volume of a cylinder head during a start-up and shut down man USA; St., Urbana, IL 61801 Green Eng., 1206 W. and Industrial Box 2053, Sys., P.O. Dept. of Manufacturing Research Laboratory, MI 48121-2053 USA MD 3135/SRL, Dearborn, (FLD) provides a useful engineering tool The forming limit diagram analysis of stamping operations. It is predi- for the development and the deformation history will follow a propor- cated on the notion that extend the utility of the FLD, recent efforts tional strain path. To of of pre-straining the sheet in a specific mode have studied the effect determination. In sheet forming practice deformation prior to FLD deformation imparted on the sheet before there is often significant specific examples of this type of punch. Two contact with the forming bending occurring during tension-leveling deformation are reversed traversing a drawbead. The objective of this operations and in material study the effect of through-thickness straining current research is to A test apparatus has on the subsequent formability of aluminum sheet. sheet of width sufficient been designed to impart reversed bending to were performed for extended limiting dome height tests. Experiments bending, and the results on both AA5754 and AA6111 sheets after detect changes in form- were compared to the original sheet stock to magnitude of through-thickness plastic pre-strain is as- The ability. texture and sessed through X-ray measurement of crystallographic residual stress. 10:40 AM during Hydroforming Formability of Aluminum Extrusions Applications Mohammad A. Khaleel evaluate alloys produced by Thixomolding that are traditionally not traditionally that are Thixomolding by alloys produced evaluate the ZK and composites metal matrix magnesium such as die cast, alloys. Break 10:10 AM 10:20 AM of Alu- on the Formability of Reversed Bending The Influence minum Sheet Pacific 3 ; Daniel 1 ; Stan G. 2 Pacific North- 1 ; 2 ; Stan G. Pitman 1 ; Russell H. Jones ; Russell H. 1 Thixomat Inc., 620 Technology Dr., Thixomat Inc., 620 Technology 2 ; Raymond F. Decker ; Raymond F. 2 Pacific Northwest National Laboratory, Pacific Northwest 1 ; Russell H. Jones Ken I. Johnson 1 ; 3 : C. Most research on the ZAC alloys has focused on com- ; Robert D. Carnahan ° 1 ; Eric A. Nyberg Eric Arthur Nyberg Pacific Northwest National Laboratory, Matls. Resources/Struc- Laboratory, Pacific Northwest National 3 2 : J. Edwards Box Battelle Blvd., P.O. Matls. Resources, west National Laboratory, 99352 USA; 999, Richland, WA Ann Arbor, MI 48108 USA have attracted inter- High temperature ZAC alloys (Mg-Zn-Al-Ca) cost, forming/processing est due to their reasonable combination of characteristics and mechanical properties. In particular, the improved high temperature creep resistance of these alloys makes them candidates for automotive applications where the creep strength of magnesium is limited because the operating temperatures exceed approximately 125 paring the die cast properties of the ZAC alloys to other alloys currently used in die cast production (AZ91D, AM50A, AM60B, AS21 and AS41). This project is part of the Northwest Alliance for Trans- program which is funded through (NATT) portation Technologies (PNGV) program. The DOE's Partnership for New Generaton Vehicles program is to address specific transportation goals aim of the NATT North- Pacific through cooperative R&D with suppliers. In this study, west National Laboratory and Thixomat Inc. have partnered to investigate the high temperature properties of ZAC8506 (8%Zn-5%Al- 0.06%Ca) comparing standard die casting and the semi-solid forming process referred to as Thixomolding. The objective of the work was to better understand the influence of lower part forming temperatures, from the semi-solid, laminar flow process (Thixomolding), on void/ pore fraction, tensile strength and high temperature creep behavior as compared to die casting. As has been shown for other alloy systems, the fraction of pores is reduced and the mechanical properties are improved when formed by Thixomolding. This work is continuing to Northwest National Laboratory, Matls. Resources/Matls. Processing, Northwest National Laboratory, 99352 USA Box 999, Richland, WA P.O. are of interest for automotive transmission Magnesium die-castings of potential to save up to 30% of the weight housings because of the However, a major drawback is the poor traditional aluminum castings. casting alloys at elevated-tempera- creep resistance of magnesium loss of bolt load retention (BLR) and subse- tures. This can result in de- flange joints. There is a current need to quent leakage of bolted the that correlate fundamental creep data with velop modeling tools This stems from the ease of creep testing BLR of actual joint designs. with BLR tests. and the relative abundance of creep data compared simplified BLR tests are Both constant load tensile creep tests and testing and finite currently performed. This paper describes material the correlation element modeling that was performed to demonstrate ZAC 8506. The goal of between these different forms of creep data for with which to optimize this research is to develop an analytical tool constitutive models based bolted joints in magnesium castings. Material MARC finite element on constant load creep tests where input to the The models include code to simulate actual bolt load retention tests. creep relaxation, thermal the effects of bolt preload, surface contact, Results are pre- expansion, and yielding due to thermal softening. the results of actual sented that compare the model predictions with used to show the relative bolt load retention tests. The models are also on the retained bolt importance of initial preload, creep, and yielding load. 9:50 AM Resistant Magnesium Alloys: Ad- High Temperature-Creep Automotive Compo- vances in the Use of Thixomolding for nents tural Matls. Dev., P.O. Box 999, Richland, WA 99352 USA; 99352 WA Box 999, Richland, P.O. tural Matls. Dev., Pitman Energy Div./Appl. Mech. Grp., P.O. Box 999, Richland, WA 99352 Richland, WA Box 999, P.O. Mech. Grp., Div./Appl. Energy USA; formation. Particular attention will be paid to analyzing local precipi- local to analyzing will be paid attention Particular formation. boundaries. grain and subgrain adjacent to the regions changes in tation micros- electron transmission based on be presented will Information dispersive spectros- energy as fine-probe as well (TEM) images copy composition profiles. copy (EDS) 9:30 AM Joints Relaxation in Bolted Modeling of Creep Finite Element Castings of Magnesium

TUESDAY AM 61 8:30 AMIntroductory Remarks WA 99027-0603USA Session Chair: Room: Mississippi March 14,2000 Tuesday AM 40202-2823 USA Corporation, DepartmentofEngineering,Louisville,KY USA; JamesN.O’Donnell,CommonwealthAluminum Corporation, GMPowertrainGroup,Pontiac,MI48340-2920 Program Organizers: Sponsored by: Solidification Cast ShopTechnology: Castingand patterns werestudiedthoroughly. thixotropic behaviorofmaterialandprocessconditionsonfilling trials confirmedthesimulationpredictions.Inaddition,effectsof be filledwithoutanydifficulties fromA356slurry. Theinitialcasting casting simulations.Simulationresultsshowedthehat-shapeddiecould semi-solid slurriesthoughtviscositymodels,wereusedtoperformthe tions foraNewtonianfluidandintroducerheologicalbehavior using singlephasesimulationapproachwhichemploygoverningequa- development program.Two softwarepackagesFlow-3DandAPECS, hat-shaped die,whichisademonstrationpartchosenbyanAlcoa ment andoptimizationtool.Thispaperpresentsafillinganalysisof merical simulationshavebeenadoptedasaprocessdesign,develop- standing ofdiefillingandsolidificationpattern.To achievethis,nu- The productionofhighqualitycomponentsrequiresdetailedunder- tially highrewardingmethodforproducingnearnet-shapedcastings. Formingalloysinthesemi-solidstateisarelativelynewbutpoten- Tech. Ctr., 100Technical Dr., AlcoaCenter, PA 15069USA Yie Zhao Casting SimulationsforSemi-SolidMetalFormingProcess 11:40 AM to reliablypredictandpreventcastingcracksduringsolidification. mined. Ahot-tearingcriterionisalsodevelopedinthispaperorder and theconditionstopreventcrackingatcastingsurfacearedeter- fication afterthemoltenmetalisinjectedintodiecavitystudied this paper,thethermomechanicalbehaviorofalloyduringsolidi- stresses developinthecastpartandcausematerialtocrack.In Due tothecharacteristicsofalloy, higherinelasticstrainsand alloy whichhasahigherstrengthandmoresusceptibleforhot-tearing. presents ahot-tearinganalysisofsolidifyingdie-castpartforan such aswroughtingot,diecastpart,foundryetc.Thispaper significant influenceonhot-tearing.Hot-tearingoccursinallcastings, sition. Processconditionsandthegeometryofacastingalsohave (hot-tearing). Thesusceptibilitylargelydependsonthealloycompo- Aluminumalloysaresusceptibletocrackingduringsolidification Tech. Ctr., 100Technical Dr., AlcoaCenter, PA 15069USA Ruan Hot-Tearing AnalysisofaSolidifyingDieCastPart 11:20 AM was conductedtounderstandthecrackinitiationmechanism. and durabilitymodelsforcast319Al.Fractographyoffailedsamples num. Resultswillbecomparedwithrecentlydevelopedconstitutive amplitudes wereusedtocharacterizetheTMFbehaviorofcastalumi- In thisstudytheroleofselectedmeanstressesandmechanicalstrain performed inairwiththetemperaturecycledbetween50and250 perature coincidingwiththemaximumcompressivestrain.Tests were cycle, thereforeexperimentswereconductedwiththemaximumtem- operation. Outofphaseloadingdominatesthecylinderheadduty 1 ; JamalRighi 1 ; Jamal Righi Light MetalsDivision,AluminumCommittee Martin J.Ekenes,Hycast,Otis Orchards, 1 ; 1 1 ; Location: OprylandConvention Center Alcoa Inc.,ShapedCastingPlatform, Paul Crepeau,GeneralMotors 1 Alcoa Inc.,ShapedCastingPlatform, : Yimin ° C. : ing TipsforAluminumSheetCasting Chemical, Physical&MechanicalProperties ofToday’s Cast- 9:00 AM a prematureendofcast. acquisition systemcanbeusedtolocalizethephenomenonthatlead A seriesofpracticalexampleswillbegiventoillustratehowadata be linkedtotheautomationandusedforanalyzingcastingconditions. tial lyingwithinapowerfuldataacquisitionsystem.Suchsystemcan the structureofamodernautomation,thispaperwillshowpoten- rameters canbekeptundertightcontrol.Afterarapidpresentationof its introductionisthedrasticreductioninsafetyhazard,asmostpa- in thecasthouse1980’s. Oneofthemainarguments justifying Automationhasproventobeavaluabletoolsinceitsintroduction agement Limited,Tech. Ctr., Chippis3965Switzerland A PotentialCastingPitCoatingMaterial 9:25 AM calculated laboratorytestresultstoproductperformanceinthefield. cies wereevaluatedanddocumented.Effortsmadetocorrelate exists withinthecastingtip.Amethodofimprovinginconsisten- mine theconsistencyofproductanditwasdeterminedvariability binders. Propertieswerealsomeasuredthroughoutthetiptodeter- shrinkage, waterabsorptionandthemeasurementoforganic/inorganic density, modulusofrupture,compressivestrength, flexuralstrength, erties includedtypicalchemistry, shotcontent,thermalconductivity, aluminum andimpactthecontinuouscastingoperation.Measuredprop- part ofthecastingprocessandcandirectlyaffectquality and arenowavailableintheglobalmarket.Castingtipsanintegral asbestos freecastingtipscurrentlyusedinthetwinrollprocess Aprogramhasbeeninstitutedtomeasurepertinentpropertiesof OH 44444USA 1 ing Automation &DataAcquisition:Tools forSafer&EasierCast- 8:35 AM results showed thatgrain refinement canconsiderablyreduce the hot- effectrefinement onhot-tearing tendency. ofgrain Theexperimental Grain refinementwas carried outinAA1050Alalloytoverifythe control toolforthecastingindustry.tearing, andpossiblyasaquality rences, andcanbefurtherdeveloped formechanisticstudiesofhot- hot-tearing occur- that theAEtechniqueiseffective indetecting was shown aided cooling-curveanalysis(CA-CCA) wasdeveloped.It Hence, a technique ofAEsignalanalysis combinedwithcomputer- ture reference-frameforsolidificationanddefectformationevents. definition forAEsignalcharacteristicsandadefinitetime-tempera- the finalfreezingzone.Thesemeasurementshaveprovidedatime of aninsertedsteelwaveguideandaK-type thermocouple placedin acquired simultaneouslywithtemperaturemonitoring bythe use were and analysis(TDA)techniques.Inlab-scaleexperiments,AEsignals situ viaanacousticemission (AE) andatemperature-dataacquisition a ring-shapedtest-castingmoldwasinvestigatedinreal-timeand in The hot-tearingtendencyofAA1050aluminumalloysolidifyingin and Metallu.ofAl,555Univ. St., Chicoutimi,QuebecG7H2B1Canada in Chicoutimi,Dept.AppliedSci.,Alcan-UQACChairSolidification Mihriban O.Pekguleryuz Via anAcousticEmissionTechnique Study ofHot-Tearing inSolidificationofAluminumAlloys 9:50 AM water aredescribedandreported. sheeting involvingsituationsofcontactwithmoltenaluminumand characteristics. Experiencesandperformanceevaluationsofrubber times, simplicityofrepair,longservicelife,andvibrationdampening low costs,multipleavailability, easeofapplication, exclusion ofcure ber sheeting,whichisorganic,asthecoatingmaterial.Theseinvolve ous. Therearemanyfavorableattributesassociatedwithutilizingrub- potential contactsurfacesofmoltenaluminumandwateriscontinu- need toenhancethesafetyperformanceofDCcastingpitsinvolving industry funded,andongoingresearchprojectforseveralyears.The mentally unfriendlyTarset coatinghasbeentheobjectofanaluminum Findinganacceptablereplacementforthefamiliar,butenviron- 1 S.C. Systems,P.O. Box6154,Moraga,CA94570USA Thermatex Corporation,Rsch.&Dev., P.O. Box125,NewtonFalls, : Patrick Pouly 1 ; EtienneCaloz 1 ; MichelBouchard 1 ; : 1 Alusuisse Technology &Man- Xiaojin Li : 1 ; : George J.Binczewski 1 University ofQuebec Jason M.Canon 1 ; Celil A.Aliravci 1 1 1 ; ; ;

TUESDAY AM 62 : University 1 ; 1 ; Ibrahim Karaman 1 Zhirui Wang, University of Toronto, Zhirui Wang, Room: Canal A Location: Opryland Convention Center , misfit strains in the range of 0.1 to 0.5, and 2 J. D. Embury, McMaster University, Matls. McMaster University, J. D. Embury, ; Scott Andrews 1 ASM International: Materials Science ASM International: of Illinois, Dept. of Mech. and Industrial Eng., Urbana, IL 61801 USA of Illinois, Dept. of Mech. and Industrial Eng., It has been widely known that both solute concentration, ie. frictional effects, and stacking fault energy influence the degree of cross- slip and slip planarity in fcc alloys (for details see Hong and Laird, 1990). Cross-slip is preceded by constriction of two partial dislocations. A model is proposed for the energy required to form a constriction from two parallel partial dislocations as a function of stacking interstitial concentration and atomic size misfit. In the fault energy, analysis, the local stress fields are calculated due to either interstitial or substitutional solute concentrations around the partial dislocations. The cross-slip is curtailed due to interaction of interstitials with the edge components of the partials. The atomic size misfit influences the local interstitial concentration, local stresses which in turn decide the energy to form the constriction. The shape of partials and the energy to form the constriction was established for stacking fault energies in the range 10-100 mJ/m nominal interstitial concentration varying from 0 to 10 atomic %. In extreme cases, the constriction energy has been found to increase by four-fold compared to the interstitial-free case. The results are readily applicable to iron alloys with carbon and nitrogen interstitials, and copper alloys with manganese, aluminum or zinc as substitutional solute atoms. The results converge to the well known solution of Stroh in the limit of zero interstitial concentration. 8:30 AM an Interstitial Field Constriction Energy in the Presence of product ductility. Assan Aluminum, in cooperation with FATA Hunter, FATA with in cooperation Aluminum, Assan ductility. product to characterize of casting trials series an extensive completed recently and gauge, speed casting including parameters, of casting the effects The foil alloys. fin and of various microstructure on the tip setback in com- and electron microscopy, examined using optical samples were resistivity micro-hardness and mechanical properties, bination with rolling used to optimize the casting, This analysis was measurements. the initial This paper presents practice for each alloy. and annealing casting general trends correlating this study and describes results from to microstructure. parameters and Fatigue of Cyclic Deformation Symposium in Honor of Materials; A Laird: Cyclic Professor Campbell and Mechanism (II) Deformation Sponsored by: Structural Materials Division, Jt. Sector, Critical Technology of Materials Mechanical Behavior Organizers: Program Toronto, Department of Metals and Materials Science, of Pennsyl- Ontario Canada; Charles McMahon, University and Engineering, vania, Department of Materials Science USA; Pedro D. Peralta, Arizona State 19104 Philadelphia, PA Department of Mechanical and Aerospace University, AZ 85287-6106 USA; J. K. Shang, Engineering, Tempe, Science and University of Illinois, Department of Materials Engineering, Urbana, IL 61801 USA Tuesday AM March 14, 2000 Session Chairs: Peralta, Arizona P. Sci. & Eng., Hamilton, Ontario Canada; Dept. of Mech. & Aerospace Eng., Tempe, State University, AZ 85287-6106 USA Huseyin Sehitoglu ; 1 Kobe 3 ; Erol 1 ; Chris ; Kenji 3 ; Alvaro 2 1 ; Seda Ertan 1 Gungor Yildizbayrak ; Shaun Hamer ; 2 1 Alcoa, Alcoa Tech. Ctr., Tech. Alcoa, Alcoa 1 ; 1 ; Kiminori Nakayama ; Lawrence J. Martonik ; Lawrence 1 1 Murat Dundar Kobe Steel Limited, Process Tech. 1 ; FATA Hunter Inc., 6147 River Crest FATA 1 Murat Dundar 3 ; 1 ; 1 Kibar Holding A.S., E-5 Karayolu 32.Km, ; Men Glenn Chu ; Men Glenn 2 1 ; Gungor Yildizbayrak 1 Makoto Morishita Douglas A. Weirauch Douglas A. : ASSAN Aluminum Works, E-5 Karayolu 32.Km, Tuzla, ASSAN Aluminum Works, 1 Kemal Sarioglu Kobe Steel Limited, Mech. Eng. Rsch. Lab., 5-5, Kobe Steel Limited, Mech. Eng. Rsch. Lab., : 2 : A. Soner Akkurt ; : 3 ; Katsuyuki Yoshikawa 3 ; Kemal Sarioglu 1 ; Donald P. Ziegler ; Donald P. 1 ASSAN Aluminum Plant, Tech. Coordination Div., Tuzla, Istanbul Tuzla, Div., Coordination ASSAN Aluminum Plant, Tech. Ozden Romanowski Tuzlal, Istanbul 81700 Turkey; Istanbul 81700 Turkey; Tuzlal, Riverside, CA 92507 USA Dr., roll casting is used throughout the aluminum industry to pro- Twin duce reroll for a variety of fin and foil products. The recent trend has been to reduce the gauge at which these casters operate to <3mm. Difficulties in industrially processing this thin gauge cast strip have been reported; in particular, maintaining satisfactory final fin and foil Istanbul 81700 Turkey; 81700 Turkey as a cost-effective roll casting has been accepted worldwide Twin This process con- method of producing wide variety of Al products. The uniform distribu- verts molten aluminium alloys into coiled sheet. with a ceramic tion of metal to the water cooled roll is accomplished fiber tip. Internal buffling configuration affects this uniform distribu- the placement tion causing defect free sheet production. In this study, of the buffles in the tip having different widths has been investigated by using computer simulation. Uniform flow distribution at the exit of the tip was attained with proper arrangement of the buffles within the Practical applications verified that unperturbed flow distribu- tip body. tion over the whole width of the tip prevented void formation at certain location of the sheet and insufficient crown formation. The goal of this research is also to find sufficient tip geometry that enables continuous metal feeding for thinner gauges. AM 11:35 Roll Cast Strip Mi- The Effect of Casting Parameters on Twin crostructure 1 Giron 1-Chome, Nishi-ku, Kobe, Hyogo 651- Rsch. Lab., 5-5, Takatsukadai 2271 Japan; Takatsukadai 1-Chome, Nishi-ku, Kobe, Hyogo 651-2271 Japan; 1-Chome, Takatsukadai 100 Tech. Dr., Alcoa Center, PA 15069-0001 USA PA Alcoa Center, Dr., 100 Tech. caster is described which permits the care- A small-scale, aluminum pa- the important continuous casting process ful control of many of the early stages of solidification. The immer- rameters which affect high-purity aluminum as a first step in quanti- sion caster is applied to process variables on cast surface features and fying the effect of key The observed characteristics of surface fea- subsurface microstructure. the basis of heat transfer and shell growth tures are interpreted on casting speed, melt superheat, mold surface kinetics. The effects of alloy solidification range are discussed. roughness, and aluminum 10:45 AM Cast Surface Structure Evolution II. Macro Laboratory Study of Air Gap Stage Tokuda Plant, 15 Kinugaoka, Steel Limited, Aluminum Rsch. Dept., Moka Japan 321-4367 Moka, Tochigi process, an exudation is At macro air gap stage of aluminum casting thermal resistance of the occurred by surface remelting because of high This exudation causes air gap between solidification shell and mold. and so forth. The some problems such as segregation, uneven structure air gap and the exudation air gap tester, which is possible to create the to molten aluminum alloy in is applied on the surface experimentally, on the exudation during order to clarify the effect of casting variables superheat, mold surface solidification. The effects of grain size, melt range are discussed. roughness and aluminum alloy solidification AM 11:10 System Used in Twin Computer Simulation of Metal Feeding Roll Casting tearing tendency in the AA1050 alloy. Fracture surface analysis was surface analysis Fracture alloy. in the AA1050 tendency tearing Typi- microscope. electron a scanning samples under for all conducted were ob- structure free dendritic with tear surfaces hot cal exposed and analyzed. served 10:15 Break 10:20 AM I. Mold Structure Evolution: Study of Cast Surface Laboratory Contact Stage

TUESDAY AM 63 quency ontheHigh CycleFatigueProperties ofAlZnMgCul,5 Influence ofThermo-Mechanical Treatment andLoading Fre- 10:35 AM 10:10 AMBreak of thesestressesonbothmonotonic andcyclicdeformation. ines avarietyofmethodsestimating thesestressesandtheinfluence residual stressesproducedbycodeformation. Thecurrentworkexam- aspect ofthesematerialswhichispoorlyunderstoodthepattern of able methodofproducingextremelyhighstrengthmaterials.One Thedeformationoftwophasematerialsrepresentsoneveryvalu- Canada 32310 USA; 1 Influence onMechanicalResponse Internal StressesinHeavilyDeformedMaterialsandTheir 9:45 AM curves wasnotdetecteduntilthefinalfailure. of strainamplitudesinvestigatedstresssaturationincyclichardening again undertotalstraincontrolmodeandthistimefortheentirerange Laird [3-5]investigatedthecyclicdeformationofsamealloy Cu-16at% Alsinglecrystalorientedforslip.However,Hongand tion behaviorandaregularcyclicstress-straincurvewithplateauin using multisteptests,Yan etal.[2]reportedtheoccurrenceofsatura- than 11at%Aldidnotshowsaturationbehaviorbeforefailure.By crystals showingclearsaturationbehavior. Alloyscontainingmore with Alcontentlessthan4at%wassimilartothatofpureCusingle single slip.Theyfoundthatthecyclichardeningbehaviorofalloys at%) onthefatiguebehaviorofCu-Alsinglecrystalsorientedfor (SFE). Abeletal.[1]studiedtheeffectofaluminumcontent(2-16 such asAlorZninordertoreducethevalueofstackingfaultenergy these studieswereusuallycopperalloyscontainingalloyingelements sometimes evencontroversialwitheachother. Thematerialsusedfor been muchless.Theavailablereportsuptodatearenotconsistentand knowledge aboutthecyclicdeformationofplanarslipmaterialshas Comparedtothecyclicdeformationofwavyslipmaterials,our 110015 China Science, StateKeyLab.forFatigueandFractureofMatls.,Shenyang Zhong GuangWang and Cu-16at%AlSingleCrystalswithDifferentOrientations Cyclic DeformationandStrainBurstBehaviorofCu-7at%Al 9:20 AM toughness ofMoSi may indicatethat(001)faultsarebeneficialforincreasingthefracture to (110)sothatacrackisarrestedby(001)faultsiftheyexist.This ness ishigherforMoSi propagates parallelto(001)faultplanes,thevalueoffracturetough- content withnotchedspecimensbythreepointbending.Whenacrack tively. FracturetoughnesshasalsobeenmeasuredasafunctionofWSi values tobe3.12+0.10and3.34forMoSi mental high-resolutionTEMimageswithcalculatedonesindicates tween Mo(W)layersaboveandbelowthefault.Matchingofexperi- dicular tothefault,whichiscausedbyrepulsiveinteractionbe- value of3,becausedilatationthelatticeindirectionperpen- n[001], however,theirnvaluesareslightlydeviatedfromtheexact the displacementvectoroffaultsisexpressedinformR=1/ lattice, givingrisetoadisplacementvectorparallel[001].When type inwhichtwosuccessive(001)Silayersareremovedfromthe WSi the solid-solutionswithdrasticincreaseoccurringonlynear these stackingfaultsincreaseswiththeincreaseinWSi faults, onlyafewfaultsareobservedinbinaryMoSi method. AlthoughbinaryWSi copy (TEM),usingtheirsinglecrystalsgrownbythefloating-zone structure havebeencharacterizedbytransmissionelectronmicros- Stackingfaultson(001)inMoSi sity, Dept. of Matls.Sci.andEng.,Sakyo-ku,Kyoto606-8501Japan ior the C11 Stacking Faultson(001)inMoSi 8:55 AM Florida StateUniversity, Nat.HighMag.FieldLab., Tallahassee, FL : 2 - endside.These(001)faultsarecharacterizedtobeoftheFrank- H. Inui b Structure andTheirInfluenceontheFracture Behav- 1 ; K.Ito 2 McMaster University, Matls.Sci.&Eng.,Hamilton, 2 1 -WSi ; XiMaoWu 1 ; T. Nakamoto 2 thanforWSi 2 solid-solutions. 2 containsahighdensityofstacking 1 ; GuangYi Li 2 1 -WSi ; M.Yamaguchi 2 whenacrackpropagatesparallel 2 -WSi : 2 solid-solutionswiththeC11 Ke Han 2 Solid-Solutionswith 1 ; 1 Chinese Academyof 1 2 1 ; J.D.Embury andWSi ; 2 . Thedensityof 1 Kyoto Univer- 2 contentin 2 respec- Π 2 2 b ; : National Laboratory, MSL-356,Livermore,CA94550USA; Sci. andEng.,Cambridge,MA02139-4307USA; Peralta Interfacial FatigueFracture inCopper-Sapphire Bicrystals 11:00 AM found inS-Nexperiments. fatigue crackcouldbedetected,whereasnoendurancelimit for T6condition.Athresholdcyclicstressintensitytopropagatea cycles. Similarly, thebestfatiguecrackgrowthpropertieswerefound deteriorated thefatigueproperties,especiallyatveryhighnumbersof condition, whereasT66aswellT64thermo-mechanicaltreatment fatigue propertiesintheS-NexperimentswerefoundforT6hardening using conventionalandultrasonicfatiguetestingequipment.Thebest frequency onthefatiguebehaviour,S-Nexperimentswereperformed increase ductility(T64).To observeaneventualinfluenceofcycling crease staticstrength(T66),andcoldworkedartificiallyagedto tions: artificiallyaged(T6),coldworkedandtoin- AlZnMgCul, 5wastestedinthreedifferentthermo-mechanicalcondi- have beeninvestigatedinthehighcycle/lowcrackgrowthrateregime. FatiguepropertiesofagehardenedAlZnMgCul,5aluminumalloy teorology &Physics,Vienna, Austria Aluminum Alloy ing topredictthe roleofprecipitatesonthedeformation resistance The presentation will highlightsomeofthemicro-mechanical model- herency andprecipitatesizeinfluences thedeformationresistance. pseudoelastic stress-strainresponse. Consequently, theprecipitateco- these materialsarealmostalways usedinagedconditiontoproduce are aknownfunctionoftheloading axisofthecrystal.Inaddition, deformation mechanisms(martensite platevariantsandslipsystems) strong advantageofsinglecrystals isthatthecharacteristicsof alloys. Inthispresentation,thefocuswillbeonsinglecrystals.The characteristics ofNiTihavebeenprimarilystudiedinpolycrystalline and stressdirectiondependent.Inthepast,cyclicdeformation Both thetransformationstrainsanddetwinningareorientation from aparenttomartensiticphase,anddetwinningofthemartensite. hardening modulus.Thedeformationiscontrolledbytransformation The increaseinstressamplitudeisprimarilyfromtheincreasingstrain as muchfactorof1.2intensionanda2compression. experiments. Thestressamplitudeunderstraincontrolcanincrease by hardening underzero-tensionandzero-compressionstraincontrol SinglecrystalNiTishapememoryalloysexhibitconsiderablecyclic Plasticity andStrengthofMatls.Lab.,Tomsk 634050Russia CO 80309USA; 61801 USA; 1 Sehitoglu Cyclic DeformationMechanismsinNiTiAlloys 11:25 AM account forthenon-crystallographicstriationsobservedisproposed. second crackdirectionhadtheminimummodeIImix.Amodelto crack growthdirectionhadthehighestenergyreleaserate,whereas stress fieldsfortheinterfacialcrackrevealedthatpreferential relatively freeoffeatures.Elasticanalysistheanistropicnear-tip observed onthecopperfracturesurface;however,largeareaswerealso cide macroscopicallywithtracesofavailableslipplanes,couldbe also resultedinaninclinedcrackfront.Striations,whichdidnotcoin- less favorablywhenthegrowthdirectionwasalong<001> Cracks grewpreferentiallywhenthegrowthdirectionwas<110> growth wereloadedintension-tensionwith (CT) specimenswithtwodifferentcrystallographicdirectionsforcrack lography andslipgeometryinthefractureprocess.Compacttension (110) bicrystals withtheboundaryperpendiculartoloadaxisand 87545 USA Alamos NationalLaboratory, MST-CMS,MSK765,LosAlamos,NM Singapore; Technological University, SchoolofMech.andProd.Eng.,639798 space Eng.,P.O. Box876106,Tempe, AZ85287-6106USA; E. Mitchell Stanzl-Tschegg University ofIllinois,Dept.Mech.andIndustrialEng.,Urbana,IL Interfacial fatiguecrackswerepropagatedincopper/sapphire Cu 1 (1010) ; U.Ramamurty 1 ; KenGall 5 3 ; Massachusetts InstituteofTechnology, Dept.ofMatls. 2 Al2O3 University ofColorado,Dept.Mech.Eng.,Boulder, 1 1 Arizona StateUniversity, Dept.ofMech.andAero- ; 3 /[001] Cu[0001] Siberian PhysicalandTechnical Institute,Physicsof 1 : University ofAgriculturalSciences,Instit.Me- 2 ; I.Karaman H. Mayer 2 ; S.Suresh 1 ; M.Papakyriacou 1 Al2O3 ; R.Anderson 3 ; G.H.Campbell tostudytheeffectofcrystal- ∆Κ 1 4 ; Y. I.Chumlyakov applied Lawrence Livermore 1 4 ; R.Pippan ; W. E.King : ≈ 2MPa.m Cu 2 Huseyin Nanyang , which Cu 1 : 5 and 4 ; S. Los ; T. 1/2 P. 3 ; .

TUESDAY AM 64 ; 2 Simon Noranda : 2 University of 1 ; Sabina Grund 1 ; 1 University of California, 1 Consultant, Alter Postweg ; 2 2 Daniela Pilone ; 1 ; C. Allen 1 Markus Andreas Reuter : : Carla Lupi TU Delft, Raw Matls. Processing, 120 Mijnbouw- 1 ; J. W. Evans ; J. W. 1 ; 1 Hoogovens Staal BV, Environmental Control & Mgmt. Control Environmental BV, Staal Hoogovens 1 A. Roy ; 1 : Inc., Tech. Ctr., 240 Hymus Blvd., Point-Claire, Quebec H9R1G5 240 Hymus Ctr., Inc., Tech. Canada The spouted bed electrode (SBE) is a particulate electrode in which metal particles may be grown from a small “seed” to particles that are a few mm across. In prior work at UC Berkeley the SBE has been studied to determine its suitability for use in electrowinning zinc (from both conventional acid sulfate electrolytes and from alkaline electro- The paper describes the results of a laboratory lytes) and copper. investigation into the application of this electrode for electrowinning from zinc chloride electrolytes. The anodic reaction was the evolution of chlorine and, when steps were taken to minimize attack of the zinc particles by this chlorine, high current efficiencies (as high as 93%) were obtained. The dependence of cell performance on some operating/design parameters such as current density (up to 4381A/m2) was examined. Reasonable electrical energy consumptions (as low as 3kWh/ straat, Delft 2628RX The Netherlands; CA 94720 USA; Dept. of Matls. Sci. and Eng., Berkeley, Honingh 1970CA The Netherlands Box 1000, IJmuiden Sys., P.O. for the pro- different options has been investigating Hoogovens have been flue dust. Four methods zinc/lead containing cessing of their dust viz. (i) scale to process this flue and/or pilot applied on laboratory (ii) hydrometallurgical processing, and subsequent pressure leaching acid in a with spent pickling of the flue dust together processing in treatment of the flue dust pyrohydrolyzer, (iii) pyrometallurgical furnace and (iv) processing of the flue an electric arc furnace/plasma results obtained will be discussed and Various dust in a cupola furnace. of process is most suitable for processing evaluated to establish which this flue dust. 9:30 AM on Zinc Electrowinning from Sulfate and Comparative Study Chloride Solutions 00184 Eudossiana 18, Roma ICMMPM, Via Rome “La Sapienza”, Dept. Italy from sulfate solutions is the traditional indus- Zinc electrowinning SHG zinc. Over the past few years several trial method to produce in order to reach efforts have been done to improve process efficiency The latter aim can be high productivity with low energy requirement. and by a reduc- pursued both by a hard purification of the electrolyte tests on indus- tion in the anodic voltage. In this work electrowinning Pb-Ag anode and by trial electrolyte have been carried out by using acetic acid or ethylene adding organic depolarizers such as ethanol, on chloride solutions glycol. At the same time tests were performed electrolyte: these experi- obtained from purification of zinc exhausted conditions by using DSA ments have been done in different operative such TEACl and anodes and by testing the effect of various additives with the two methods it TBACl. Comparing the best results obtained electrowon in both cases, can be highlighted that a high quality zinc is of zinc chloride elec- but the energy requirement is lower in the case trowinning. 9:50 AM Metallurgical The Use of Data Reconciliation to Optimise Plants-Case Study Zn Plant Thomas Auping 12, Dorsten 46282 Germany as a tool to assist in the This paper discusses data reconciliation plants. After discussing modeling and optimisation of metallurgical an industrial hydro- the theory the methodology is illustrated using sections of the plant Various zinc plant as a case study. metallurgical and practical useful rela- are mass balanced and various fundamental tionships are derived. These are discussed in terms of among others process control, metallurgical control, accounting and environmental monitoring. 10:10 AM Spouted Bed Electrowinning of Zinc from Zinc Chloride Elec- trolytes 9:10 AM 9:10 to Alters Gradually Steel Industries Integrated Zincproblem Aid of Metallurgy with the and Zinc of Lead Source ; ; ; 2 2 1 Union 3 ; P. Verguts ; P. 1 ; I. Dañobeitia 1 ; N. Goicoechea 1 KU Leuven, Dept. of 1 ; Union Minière, B.U. Pre- 3 2 Bart Blanpain UMR, Dept. of Metallu., 210 3 ; Nancy Ayala : 1 CENIM, Centro Nacional de 1 ; E. García-Ventosa 1 ; 3 in, University of Missouri, Rolla, MO in, University of Missouri, Markus Reuter, Delft University of Markus Reuter, ; Frank De Buyck 2 Room: Bayou D Convention Center Location: Opryland M. A. Reuter, Delft University of Technol- Delft M. A. Reuter, Extraction & Processing Division, Lead, & Processing Division, Extraction Eric G. Allain Eric Alla ; Enrique Ruiz-Ayúcar ; 1 1 : Fernando García-Carcedo ; S. Brouwer 1 Compañía Industrial ASER, S.A. Carretera Bilbao-Plencia, Asúa- 2 Erandio, Bilbao, Vizcaya 48950 Spain; Erandio, Bilbao, Vizcaya Investigaciones Metalúrgicas, C/. Gregorio del Amo 8, Madrid 28040 Spain; Fulton Hall, Rolla, MO 65401 USA This research aimed to develop a clean technology for the produc- The tion of ZnO from residues generated by the steel making industry. scientific and technologic parameters were both investigated in order to define an industrial methodology allowing the integral recycling of EAF dusts. A reengineering of the Wáelz process was performed, aiming to produce a clean fraction of ZnO, free of fluorine, as well as a slag enriched in metallic iron, which can be recycled to the electric arc furnace. The technical conditions used to produce the ultra pure fraction of ZnO are described. The magnetic separation of the EAF dust allowing the production of a phase high in iron and directly recyclable to the electric arc furnace is also discussed. Thermodynamic of the volatilization of all the elements contained in the EAF dust was performed in order to allow a better control of the thermal process in the reducing agents, weakly or were run using different rotary kiln. Tests highly reactive, to determine their specific efficiency. Metallu. and Matls. Eng., Leuven Belgium; B-2660 Belgium; cious Metals, A. Greinerstraat 14, Hoboken A. Hernández N. Cornejo 8:30 AM Modeling of the Lead Blast Furnace March 14, 2000 Session Chair: Sci., Delft, RX 2628 The Netherlands Appl. Earth ogy, Belgium Minière, Research, Kasteelstraat 7, Olen B-2250 metal producers in Union Minière, one of the major non-ferrous recently changed its the world with several industrial sites in Belgium, Before the change, flow sheet substantially. copper-lead metallurgy were fed into a blast lead-copper ore sinter and secondary materials are smelted in the blast furnace. Now only secondary raw materials low in comparison with furnace. Since the porosity of this feed is very occur very slowly. the former sintered ores, the gas-solid reactions a changed considerably, Because the process of the blast furnace has constructed as a tool to mathematical model of the furnace is being The model uses general study the phenomena occurring in the furnace. models for porous zones, Computational Fluid Dynamics together with to study the influence of combustion and so on. The model will be used in order to opti- operating parameters on blast furnace phenomena of the model, together mize blast furnace performance. An outline with first results will be discussed. 8:50 AM ZnO by the Recycling Production of an Ultra-Pure Fraction of of EAF Dust Tuesday AM Fundamentals of Lead and Zinc of Lead Fundamentals I Session and Recycling: Extraction by: Sponsored Delft 2628 RX The Applied Earth Sciences, Technology, Netherlands; 65409-1460 USA Zinc, and Tin Committee Zinc, and Tin Organizers: Program and explain the strong dependence of orientation and stress direction and stress of orientation dependence the strong and explain fatigue response. on the Wollants P.

TUESDAY AM 65 Clair C.Calvert tion ofxenotime rawmaterialbyrare-earthelements/compounds has lish optimizedconditions forthereaction.Thekinetics ofchlorina- been performed.Particularemphasis wasonkineticsstudiestoestab- of thereactionbetweenxenotime (REPO much workconcerningchlorination. Inthiswork,asystematicstudy and sodiumhydroxideathightemperatures; however,thereisnot major processesofdecomposition ofrare-earthoresusesulfuricacid precursors inthedevelopmentof newmaterialsandprocess.The route inordertoobtainintermetalliccompounds,whichareused as vanced ceramicsareashasbeenwidelyinvestigatedasapreparative Theutilizationofchlorinationinextractivemetallurgyandad- Av. Bandeirantes3900,RibeirãoPreto,SãoPaulo14040-901Brazil 1 of Carbon Chlorination KineticsofXenotimewithChlorineinPresence 8:55 AM the influenceofdifferentoxygenpartialpressuresandtemperatures. spinoidal decompositionofcomplexspinelphaseshasoccurredunder der diffractiondata.Itisevidentfromtheexperimentalresultsthat these valueswerecomparedwiththeobtainedfromX-raypow- studies wereusedtocalculatelatticeparameterofthespineland tron probemicroanalyser(EPMA).TheresultsobtainedfromEPMA in elementalcompositiondifferentphaseswereanalysedbyelec- examined usingscanningelectronmicroscope(SEM)andthechanges calcined producthasbeendiscussed.Themicrostructuralchangeswere partial pressureandtemperatureonthephaseconstituentsof temperature rangefrom200to1200 mineral inair,argonand5%hydrogen+atmospheresovera natural chromitemineralshasbeeninvestigatedbycalcining the crystallographyofdifferentchromiteminerals.Phaseequilibriain tions. Experimentswerecarriedoutinordertostudythedifferences the Cr have beensystematicallyinvestigatedinviewofthephaseequilibria tial onthemicrostructureandcompositionofmineralphasesformed effect theprocessingparametersi.e.temperatureandoxygenpoten- structure asafunctionoftemperatureandgaseousatmosphere.The investigated theeffectofheattreatmentonmineralcompositionand the extractionchemistryofchromiumspecies.Inthispaper,wehave chromite phasearethereforeimportantpartofourinvestigationon mium metalandchemicals.Themineralogycrystalstructureof Chromiteoreisofimmenseimportancetotheextractionchro- UK; 1 Equilibria ofNaturalChromite Minerals ofTemperatureEffect and OxygenPartial Pressure onPhase 8:30 AM 10591-6714 USA Session Chair: March 14,2000 Tuesday AM Taskinen, OutokumpuResearch Oy, PoriFIN-28101Finland Research, Trail,BritishColumbiaV1R4S4Canada;Pekka Program Organizers: allurgy Committee Sponsored by: Minerals andMetals Pyrometallurgical Processingof General Non-FerrousPyrometallurgy: metallic tothenakedeyeanddenseunderSEM. kg Zn)werefoundundermanycircumstances.Zincdepositsappeared Faculdade deFilosofia,CiênciaseLetrasRib.Preto-USP, Chem., University ofLeeds,Dept.Matls.,West Yorkshire LS29JT 2 Elementis Chromium,Egalescliff, Stockton-on-Tees, UK 2 O 3 -Al : MarcoAntonioGimenes 2 O 3 -Fe 1 ; AnimeshJha Extraction &ProcessingDivision,Pyromet- Adrian C.Deneys,Praxair, Tarrytown, NY x O y -MgO systemandspinoidaldecompositionreac- Location: OprylandConventionCenter Room: BayouB Robert L.Stephens,Cominco 1 ; M.P. Antony 1 ; ° C. Theeffectoftheoxygen Herenilton PaulinoOliveira 4 ), chlorine,andcarbonhas : Vilas D.Tathavadkar 1 ; MartinWilkinson 2 1 1 ; ; ; 543,000+64.6T[J/mol](1848 to1973K),Y 566,000+103T[J/mol](1673 to1873K),1/2O conium Thermodynamics ofDeoxidationMoltenTitaniumandZir- 9:45 AM flash reactionsandservesasreferenceforcomputersimulations. ments enlargestheknowledgeofphysicalandchemicalphenomenain dust formationandreactionmechanisms.Dataobtainedintheexperi- tion phenomenonand,consequently, to compose adetailedmodelof position areviewedtocloselyfollowthedevelopmentofoxida- particles arediscussed.Changesinparticlemorphology, size,andcom- occurring duringreactions.Oxidationkineticsaswellignitionof microscopy withEDS-analyserwereusedtoexaminethephenomena define theirrespectiveremovalrates.Opticalandscanningelectron to 75vol%.SampleswereanalysedchemicallyforCu,FeandS tures of1100and1300 them intoawaterfilm.Experimentalconditionsincludedtempera- nace andsampledaftershortreactiontimeintervalsbyquenching furnace. Intheexperiments,screenedfractionswerefedintofur- lating thephenomenatakingplaceinreactionshaftofaflash mattes werestudiedusingalaboratoryscalelaminar-flowfurnacesimu- Oxidationofchalcopyriteconcentrateandtwolow-ironcopper 02015 Finland Lab. ofMatls.Proc.andPowderMetallu.,P.O. Box6200,Espoo influence ontherateofconversionxenotimetoRECl been studiedoveratemperaturerangefrom600 different slagsintheCaF tally investigated.Theremelting experimentswerecarriedoutwith Electroslagremelting(ESR)of Cu-Cr-Zralloyhasbeenexperimen- Research Institute,505WuNing Rd., Shanghai200063PRC Yan ChangRd.,Shanghai 200072PRC; Shen Study onElectroslag RemeltingofCu-Cr-ZrAlloy 10:20 AM 10:10 Break dynamic data. using yttrium-basedfluxesarediscussedbasedontheobservedthermo- 317T[J/mol](2153 to2173K).Thepossibilitiesofdeoxidation by Y Ti)+3O(mass pct,inTi), The resultsaresummarizedasfollows:1/2O were equilibratedwithaY nique. Moltentitanium,zirconium,andtheiralloyswithaluminum and zirconiumhavebeeninvestigatedbyachemicalequilibriumtech- thermodynamic propertiesofoxygenandyttriuminmoltentitanium ten titaniumandzirconiumhasnotbeenestablished.Inthisstudy, have notbeenclarifiedandtheeffectivedeoxidationprocessofmol- modynamic propertiesofoxygeninmoltentitaniumandzirconium and physicalpropertiessuchasductilitytoughness.However,ther- for useinapplicationbecauseitsignificantlyaffectsthemechanical Theremovalofoxygenfromtitaniumandzirconiumisimportant Japan of AdvancedMatls.Sci.,7-3-1Hongo,Bunkyo-ku,Tokyo 113-0033 Tsukuba-shi, Ibaraki305-0047Japan; search InstituteforMetals,Matls.CreationRsch.Station,1-2-1,Sengen, Peuraniemi Reaction SequencesinSulphideParticleOxidation 9:20 AM+ 1). chloride. We thankFAPESP forfinancialsupport(proc.:1997/05779- presence ofanintermediatestepbeforetheformationlanthanide ride (YOCl),indicatingthatthereactionmechanisminvolves ing clearlythepatternsrelatedtoformationofyttriumoxychlo- The powderX-raydiffractiontechniquecorroboratedthemodelshow- unreacted coreshrinkingmodelwithaformationofproductlayer. eters hasbeendeveloped.Theresultsshowthattheprocessfollows were investigated.Aglobalrateequationthatincludestheseparam- ture, partialpressureofchlorine,carboncontent,andparticlesize losses ofalloying elements(ZrandCr)hasbeenconsidered andexam- tems inanESunit of25kgcapacity. Theinfluenceofslagonthe 2 O 3 2 (s)=2Y(mass pct,inZr)+3O(massZr)and ; Ji HeWei : Yoshinao Kobayashi 1 ; AriJokilaakso 1 ; 1 Shanghai University, Dept. ofMetallicMatls.,149 ° C withreactiongasoxygencontentsfrom21 2 ∆ +NaF, CaF 2 O G 3 1 0 , Al ; =601,000-262T[J/mol](1991 to2093K), 1 ; FumitakaTsukihashi 1 2 Helsinki UniversityofTechnology, O 3 , orZrO 2 +ZrO 2 The UniversityofTokyo, Dept. 2 Shanghai ElectricalApparatus 2 andCaF 2 2 2 pelletinacoldcrucible. 2 (g)=O(X (g)=O(X O 3 (s)=2Y(mass pct,in ° C to1100 2 2 +NaF+ZrO O ; O , inZr), , inTi), ∆ 1 3 National Re- G oftempera- : 0 =736,000- : Xiao Yu ° C. The Esa J. ∆ ∆ 2 sys- G G 0 0 =- =-

TUESDAY AM 66 ; M. 2 ; Peter 1 University Chau-Yun 1 were studied : ; C. Park ; 3 2 2 O 2 Argonne National Labo- 1 , and Yb 2 Dean J. Miller ; ; J. E. Mathis rotated grains. The YBCO 2 2 ° : ; D. M. Kroeger 2 Oak Ridge National Laboratory, 2 ; F. A. List ; F. 2 ; D. P. Norton ; D. P. 2 ; Dave K. Christen 2 does not show the same island microstructure, ; A. Goyal 1 2 ; D. F. Lee ; D. F. 2 ; Ron Feenstra 1 Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA Oak Ridge National Laboratory, 2 has an island microstructure like that of YBCO on YSZ. These has an island microstructure like that of YBCO 3 ; S. E. Babcock 1 O 2 Berghuis IL 60439 9500 S. Cass, MSD-223, Argonne, Matls. Sci. Div., ratory, USA; rather a single YBCO grain that contains twin boundaries on both sets rather a single YBCO grain that contains twin 20 microns observable of {110} planes extend over the entire 10 to widely dispersed area of TEM specimens. Although some dislocations from YBCO on a in the film, no clear domain structure is observed factors are open observed main current limiting given Ni grain. Two grain boundaries. The pores and poor YBCO connection across Ni 0.2 MA/cm2. The high Jc results is a films with a low Jc value of just ~ developed new buffer (1.7MA/cm2) YBCO film grown on recently Yb length scale ranging from results suggest that microstructural details of This layer. on the buffer sub-micron to many tens of microns depend work is supported by US-DOE through ORNL. 9:50 AM Break 10:00 AM Invited Currents of Grain Boundary Transport Measurements Direct in YBa2Cu3Ox Coated Conductors The impressive transport properties achieved in YBa2Cu3Ox coated conductors have led to an intense effort to understand the key factors that influence the critical current and current density on this type of In this work, we aim to understand the current path in these conductor. conductors and particularly how grain boundaries influence the critical use micropatterning techniques to isolate indi- We current density. vidual grain boundaries on coated conductors prepared using RABiTS substrates. The transport properties measured across these single grain boundaries are then compared to those across grain boundaries from thin film and bulk bicrystals as well as to the global transport properties of coated conductors. In this presentation, details of the patterning and measurement of critical currents will be presented. An emphasis will be placed on the comparison with global transport properties and the influence of the criterion used to establish the critical current. This work was partially supported by the U.S. Department of Energy, Basic Energy Sciences-Materials Sciences and Energy Efficiency and under contract #W-31-109-ENG-38. Renewable Energy, Advances in the fabrication of Rolling assisted biaxially textured biaxially assisted of Rolling the fabrication in Advances HTS on of or formation deposition and epitaxial (RABiTS) substrates in the been made progress has Significant reported. is such substrates metal textured biaxially strengthened, of non-magnetic, fabrication in the fab- other buffer layers and of oxide and templates, deposition ex- High Jc’s and superconductors. long length substrates rication of grown YBCO on epitaxially have been demonstrated ceeding 1 MA/cm2 have Jc’s the starting template. High using Ni-Cr as films on RABiTS of new buffer layer configurations on a variety been demonstrated to fabricate Efforts are underway buffer layers. including conducting samples exceeding 10cm and results ob- longer length superconductor to Particular emphasis would be given tained will also be summarized. affecting Jc in coated conductors. Research microstructural factors of Energy under contract DE-AC05- sponsored by U. S. Department Martin Energy Research Corporation. 96OR22464 to Lockheed 9:10 AM Films Deposited on Oxide Buffered Microstructure of YBCO Ni Substrates Textured Rolling Assisted Biaxially Yang Paranthaman 1500 Engineer- Ctr., Appl. Superconductivity of Wisconsin-Madison, USA; Madison, WI 53706 ing Dr., Box 2008, Oak Ridge, TN 37831 USA P.O. YBCO films on differ- The microstructures of pulsed laser deposited ent buffer layer materials including YSZ, CeO defects and elucidating with a view toward identifying current limiting coated conductors. The the roles of the buffer layer material in YBCO microstructure, and YBCO films deposited on YSZ possess an island thickness. The observed the island size increases with increasing film low angle grain bound- current limiting mechanisms are unlikely to be the columnar pores aries between YBCO islands but pores, especially the films are over 1 elongated through YBCO [001] direction when mm thick, second phase particles, and 45 film grown on CeO ; 1 ; C. 1 Zhiyu ; D. P. 1 C, HRB : 3 ° O Oak Ridge 2 1 ; ; T. Autug ; T. 1 1 ; C. Park 1 ; D. M. Kreoeger 1 was studied by TG 3 Northeastern Univer- 1 O 2 ; 1 ; D. F. Lee ; D. F. 1 ; D. B. Beach ; T. Chirayil ; T. 1 1 give mainly VC, and there are 3 ; D. T. Verebelyi ; D. T. 1 O 2 system and the remelted Cu-Cr-Zr and the system 2 ; Jing Yang 1 ; F. A. List ; F. 1 U. Balu Balachandran, Argonne is an important raw material due to its low ; E. D. Specht ; P. M. Martin ; P. 3 ; R. Feenstra 1 1 1 Room: Canal D Location: Opryland Convention Center 0 2 +NaF+ZrO 2 Amit Goyal Chandra S Pande, Naval Research Labora- system and other operation parameters employed, a other operation parameters system and Electronic, Magnetic & Photonic Materials 2 : ; Zhenqi Huang 1 ; X. Cui 1 ; D. K. Christen ; R. K. Williams 1 1 +NaF+ZrO 2 can provide valuable information to the production of VC, VN, can provide valuable information to the production 3 ; Zhitong Sui 1 O 2 Norton 8:30 AM Invited High-Jc, YBCO Conductors Fabricated by Epitaxial Deposi- Sub- tion of YBCO on Rolling Assisted Biaxially Textured strates (RABiTS) M. Paranthaman Cantoni MS 6116, Box 2008; Metals and Ceramics, P.O. National Laboratory, Bldg. 4500S; Rm. B-248, Oak Ridge, TN 37831 USA Tuesday AM National Laboratory, Argonne, IL 60439 USA; Pradeep Argonne, National Laboratory, General Corporation, Latham, NY Intermagnetics Haldar, 12110-0461 USA; Chandra Pande, Naval Research Labora- Division, Washing- Materials Science and Technology tory, ton, DC 20375-5000 USA March 14, 2000 Session Chair: DC 20375 USA Washington, Matls. Sci. Div., tory, High-Temperature Superconductors: High-Temperature Coated Conductors Sponsored by: Division, Structural Materials Division, Superconducting Division, Structural Materials Division, Materials Committee Program Organizers: V(C,N). In this paper the reduction process of V V(C,N). In this paper the reduction process of the reduction rate was and XRD method, the study results reveal that step and mass trans- controlled by both interface chemical reaction scope (1300K—1700K). port step in the experimental temperature chemical reaction The apparent activation energy for the interface for the mass transport was 34kJ/mole; the apparent activation energy mechanism can give step was 32kJ/mole. The study on the reduction is lower than 1300K, the following conclusion. When the temperature the carbon reduction mechanism of V is a self-catalyzed reac- enough clues indicates that the main reaction tion at this temperature range. oxygen content in the molecule, so the kinetic study on reduction of oxygen content in the molecule, so the kinetic V Lu PRC Shenyang 110006 School of Matl. and Metallu., sity, in making high strength is an important alloy element Vanadium vanadium can play the role of dispersion low alloy steel in which In recent years there has been great interest strengthening to the steel. vanadium nitride (VN) and vanadium carbide in vanadium carbide (VC), all of the three compounds can exhibit excel- nitride (V(C,N)), because of vanadium to the molten steel. In mak- lent quality for the addition ing these compounds V high quality ingot of Cu-Cr-Zr alloy may be made with high yields of may be made with ingot of Cu-Cr-Zr alloy high quality alloy with a the remelted Cu-Cr-Zr means of ESR. For Zr and Cr by Zr, the soften- Cr and 0.1 mass-% of 0.5-mass% specified composition 550 conductivity are hardness and electrical ing temperature, ined. The technologies of the pressure working and heat treatment of heat treatment working and pressure of the The technologies ined. proper- physical Some and discussed. been described ingot have the ER CaF the slag in ties of of Cu-Cr-Zr The properties MS/m, respectively. than 43 75 and larger with and superior to the requirements alloy products are in accordance 5182-1991(E). and specifications of ISO 10:45 AM Carbon Thermal Reduction of V Kinetic Study on the alloy have been determined. The results indicated that with the slag in with the indicated that The results have been determined. alloy a CaF

TUESDAY AM 67 University, Dept.ofElect.Eng.,Evanston,IL60208USA; 8:30 AMOpening Remarks Sci. andEng.Dept.,LosAngeles, CA90095-1595USA Session Chair: March 14,2000 Tuesday AM Materials EngineeringDivision,Livermore,CA94550USA Lawrence LivermoreNationalLaboratory, Manufacturing& Laboratory, Livermore,CA94550USA;Chol K.Syn, 1063 USA;DonaldR.Lesuer, LawrenceLivermoreNational Mechanical EngineeringDepartment,Austin,TX78712- Program Organizers: als Committee,ShapingandFormingCommittee Processing andManufacturingDivision,StructuralMateri- Sponsored by: and BehaviorA Oleg D.Sherby:CreepMechanisms Honorary SymposiumforProfessor energy, andgrowalongthea-axisrapidlyresultinginatexturedfilm. face ofthesilveralloyinaparallelfashiontominimizeitssurface cess. Duringsolidification,theYBCOgrainswillnucleateonsur- achieve thegraintexturinginperitectic-reaction-controlledpro- force. We foundthatagrain-orientedsubstratemaynotberequiredto temperature wasloweredto950 observed onthesurfaceofsilveralloysubstrateasquenching (the samplewaspre-meltedat1030 structure asaresultofrapida-growthwhenquenchedfrom1000 substrate. TheinitialYBCOmorphologyexhibitsacolumn-likegrain perature forthethickfilmsofYBa2Cu3Ox(YBCO)onsilveralloy Quenchingexperimentswerecarriedoutneartheperitectictem- Hall, MailLocation0012,Cincinnati,OH45221-0012USA Donglu Shi a SilverAlloySubstratethroughPeritecticSolidification A StudyontheGrainTexturing MechanismofYBCOFilmon 11:20 AMInvited Superconductivity (GrantNo.DMR91-2000). Science FoundationthroughtheandTechnology Centerfor Contract W-31-109-Eng-38.Work atNUsupportedbytheNational as partofaprogramtodevelopelectricpowertechnology, under U.S. DepartmentofEnergy, Energy Efficiency andRenewableEnergy, cussed. *Work atANLand part oftheworkatIGCsupportedby sition conditionsrequiredtoobtainthetexturedlayerswillbedis- (critical currentdensity>1MA/cm processing parameterswereoptimizedandcriticalcurrentsof>50A by metal-organicchemicalvapordeposition(MOCVD).TheMOCVD superconductors of deposited onIBAD/YSZfilmsbyelectronbeamevaporation.YBCO of YSZwereinvestigated.Epitaxialcaplayersceriumoxide ion-to-atom fluxratioandbeamopticsdivergenceonin-planetexture and anargon-iongunaidedtexturedevelopmentintheYSZ.Effectsof (IBAD). Atomicplumeswerecreatedbyelectronbeamevaporation ited onpolishedHastelloysubstratesviaion-beam-assisteddeposition Biaxiallyalignedyttria-stabilizedzirconia(YSZ)filmsweredepos- 3 Tech., 9700S.CassAve., Argonne, IL60440USA; Selvamanickam U. Balachandran IBAD/MOCVD-Based YBCO-CoatedConductorDevelopment 10:40 AM Intermagnetics GeneralCorporation,Latham,NY12110USA 1 ; 1 University ofCincinnati,Matls.Sci.&Eng.,498Rhodes 3 ; P. Haldar 1 ; M.P. Chudzik Structural MaterialsDivision, Alan Ardell,UniversityofCalifornia, Matls. ≈ 1 µmthicknessweredepositedonceriacaplayers Location: OprylandConvention Center Room: BayouE Eric M.Taleff, UniversityofTexas, 3 ; 1 Argonne NationalLaboratory, Energy ° 1 C providingamuchgreaterdriving ; R.A.Erck 2 ) wereobtainedat77K.Thedepo- ° C). Awaffle-likestructurewas 1 ; C.R.Kannewurf 2 Northwestern 2 ; V. ° C : : Flow The Interpretation ofCreep MechanismsinHighTemperature 9:10 AMInvited vated dislocationcuttingprocesses. room temperature.Thisappearstobecontrolledbythermallyacti- films. Sometime-dependentstressrelaxationisobservedinAufilmsat and comparedwiththehardeningprocessesthatoccurinsinglecrystal sistance. Thehardeningeffectsofgrainboundariesarealsoexplored strate andfilm/passivationinterfacesdominatesthedeformationre- sivated thinfilmsbecausethestorageofdislocationsatfilm/sub- dislocation processes.Dislocationplasticityislargelyathermalinpas- served. Forpassivatedfilms,plasticityappearstobedominatedby that dislocationplasticitymustbeactivewhenfullrelaxationisob- the stressescompletelyathightemperatures,withconsequence film/substrate interface,diffusionaldeformationalonecannotrelax unless thefilm/substrateisfreetoslide.Forcaseofnoslidingat that classicalCobleorHerring-Nabarrocreeprelationsdonotapply constrained bykineticprocessesatthefilm/substrateinterfaceand port betweenthefreesurfaceoffilmandgrainboundariesis films itisshownthatdiffusionaldeformationinvolvingmasstrans- inhibited bythepresenceofthinpassivatinglayers.Forunpassivated utes toplasticityinthesefine-grainedmaterials,thoughitcanbe of dislocationsandgrainboundaries.Diffusionaldeformationcontrib- ticular referencetounderstandingthesofteningandhardeningeffects metal films(Al,Cu,Au)onsiliconsubstratesarereviewedwithpar- Mechanismsoftime-dependentplasticityinpolycrystallinethin 94087-2205 USA Matls. Sci.andEng.,416EscondidoMall,Bldg.550,Stanford,CA Thin FilmsonSubstrates Mechanisms ofTime-DependentPlasticityinPolycrystalline 8:40 AMKeynote ture creepafterstress reductionsoccursbyparallel processesofdislo- of temperaturesand stresses.Theseresultsshow that constantstruc- numerous investigationspresenta consistent pictureoverawiderange is giventothelatterinpresent discussion.Dataforaluminumfrom While bothtypesofexperimentsgive similarresults,greateremphasis strain ratechangeexperimentsand stresschangetestsareconsidered. understanding ofthemechanisms ofdeformation.Datafromboth ture isreviewed,withthegoalofusing theseresultstodevelopabetter Theanalysisofcreepunderconditionsconstantinternalstruc- USA Chem. Eng.andMatls.Sci.,OneShieldsAve., Davis,CA95616-5294 World Constant StructureCreepofAluminum:AlltheDatain 9:50 AMInvited Metals Forum,4,1981,pp.53-56. A.K. MillerandM.E.Kassner,“SubgrainStrengtheningRevisited”, stresses inassociationwithdislocationheterogeneities.[1]O.D.Sherby, beam electrondiffractionexperimentsonmetalstoevaluateinternal discussions ofrecentin-situTEM,x-raydiffractionandconvergent recent developmentsregardinginternalback-stresses.Thiswillinclude law-creep insingle-phasemetals.Particularattentionisdevotedto subgrain boundaries,ontherate-controllingprocessforfivepower- discern thecontributionsofvarioussubstructuralfeatures,including in thisarea,includinginvestigationsbytheauthor,thatattemptedto ture plasticity[1].Thisworkdiscussessomeofthemorerecent the authoroneffectsofsubgrainboundarieselevated-tempera- ThisworkisasequeltoearlierwithProf.OlegD.Sherbyand OR 97331USA 1 Subgrain StrengtheningRevisitedII 9:30 AMInvited tification. crystalline solidsandexaminesproceduresfortheirunambiguousiden- energy. Thispaperconsidersthedifferent creepprocessesoccurringin based onmeasurementsofthestressexponentandactivation creep andanidentificationoftherate-controllingprocessisgenerally Severaldifferentflowmechanismsmayoccurinhightemperature USA Depts. ofMatls.Sci.&Mech.Eng.,LosAngeles,CA90089-1453 Oregon StateUniversity, Dept.Mech.Eng.,RogersHall,Corvallis, : : Terence G.Langdon Jeffrey C.Gibeling : 1 1 William D.Nix ; ; 1 1 University ofSouthernCalifornia, University ofCalifornia,Dept. : Michael ErnestKassner 1 ; 1 Stanford University, 1 ;

TUESDAY AM 68 ; 2 ; Oleg D. Sherby 1 ; Chol K. Syn 1 Stanford University, Dept. of Matls. Sci. and Dept. of Matls. Stanford University, 2 Donald R. Lesuer : Lawrence Livermore National Laboratory, L-342, P.O. Box 808, L-342, P.O. Lawrence Livermore National Laboratory, rate ratio predicted using these anisotropy parameters was in reason- was in parameters anisotropy using these predicted rate ratio large relatively results albeit the experimental with able agreement deter- texture was The crystallographic in the data. was noted scatter from pole figures and direct via inverse diffraction using x-ray mined were de- functions (CODF) orientation distribution which crystallite with slip plasticity in conjunction based on crystal rived. Predictions to arise which were initially thought large deviations, CODF exhibited Dislocation and/or second phase. from twinning from contributions stress level as a function of the were investigated microstructures equi-biaxial (=) and creep tests at uniaxial following At stresses below about 180 MPa, dislocation (=1) loading. random while at higher stresses (at ~211 arrangement was generally formation was noted. Whereas, uniaxially loaded MPa) distinct subgrain distribution of dislocations even at very samples exhibited random In all cases, the dislocations are predomi- high stresses (~351 MPa). on {10 0} planes. Some type disloca- nantly <11 0> type lying are few low angle grain boundaries, and these tions were observed in No twins were noted while only small relatively widely separated. phase were observed confined mainly to grain amounts of  boundaries. AM Invited 11:30 Law Breakdown in Metals, Alloys and An Evaluation of Power Compounds 1 Livermore, CA USA; Eng., Stanford, CA 94305 USA rates that do not follow Creep at high stresses often produces strain and stress. At low stress, a power law relationship between strain rate high stress, greater strain a power law relationship is observed while, at by this relationship. This rates are observed than would be predicted (PLB). In this phenomena is referred to as Power Law Breakdown at high stress in pure paper, we examine the available creep data alloys and com- metals, solid solution alloys, dispersion strengthened and experimental condi- pounds to identify materials characteristics that result in PLB. The tions (stress, temperature and strain rate) of these higher stresses results are analyzed by assessing the influence For a number of Fe-C and strain rates on the diffusion coefficient. in dislocation density alloys, PLB can be explained by the increase When in diffusivity. with increasing stress and the resulting increase in terms of an effective creep results in the Fe-C alloys are analyzed PLB disappears. which includes lattice and pipe diffusion, diffusivity, in terms of the production Power Law Breakdown has also been studied vacancies on the diffu- of excess vacancies and the influence of excess to study PLB sion coefficient. A simple model has been constructed of vacancies. The based on the rates of production and annihilation for PLB in metals alloys results provide insight into the physical basis performed under the auspices of the U.S. De- and compounds. Work National Laboratory partment of Energy by the Lawrence Livermore under contract W-7405-ENG-48. ; : 1 UCLA, Matls. 1 ; K. Linga Murty Defence Metallur- 1 3 : MCNC Electronic and Infor- 2 .5V Tubing 2 Al 3 ; Marek A. Przystupa 1 North Carolina State University, P.O. Box P.O. North Carolina State University, 1 ; 3 Northwestern University, Dept. of Matls. Sci. Dept. Northwestern University, 1 ; 1 Alan J. Ardell : ; A. Paradkar 2 .5V tubing by varying the internal pressurization superimposed 2 Al 3 7909, Raleigh, NC 27695-7909 USA; NC 27709-2889 USA; RTP, mation Technologies, Hyderabad, India gical Research Laboratory, Biaxial creep characteristics were investigated on recrystallized Ti with axial load at 673K. The stress ratio () of the hoop to axial was varied from 0 to while the hoop and axial creep strains were respec- monitored using a telemetric laser extensometer and an LVDT dissipation rate The creep locus defined at a constant energy tively. deviated from isotropy with relatively large hardening towards the equation axial stress axis. The results were fit to the modified Hill’s were derived from which the creep anisotropy parameters, R and P, and these parameters deviated from unity with R quite large (~6) and P relatively smaller (~0.5). The stress-state dependence of the strain- Sci. and Eng., 6531-G Boelter Hall, Los Angeles, CA 90095-1595 USA Sci. and Eng., 6531-G Boelter Hall, Los Angeles, deformation The dislocation network theory of high-temperature creep that other theo- explains many features of Harper-Dorn (H-D) in the H-D creep regime ries do not. One is that the dislocation density of dislocation network is independent of the applied stress. Frustration rule cannot be satisfied at the nodes coarsening, arising because Frank’s are eliminated, is respon- when the network coarsens and dislocations primary creep in the sible. The reduction in dislocation density during equations of the H-D regime is also satisfactorily explained. Previous kind of node resulting network theory involved formation of only one In real f.c.c. crystals sev- from dislocation collisions and annihilation. to different configura- eral kinds of interactions are possible, leading tions at dislocation nodes. In the present work we take these into apply the new equations to describe the experimentally account. We also at- measured distributions of dislocation link lengths in Al. We tempt to provide a self-consistent prediction of creep curves in Al deformed in the H-D regime. AM Invited 11:10 Effect of Stress-Ratio on Biaxial Creep and Dislocation Micro- Ti in Recrystallized structures S. Nangalia & Eng., Evanston, IL 60208 USA & Eng., Evanston, IL of about 3 at the Many alloys have a “natural” power law exponent have an “unnatural” higher temperatures. Pure metals and some alloys temperatures and an power law exponent of about 5 at the higher of 5) at moderately unnatural power law exponent of about 7 (instead the discrepancy of the high temperatures. It is argued in this talk that as the occurrence of exponent in high temperature creep, as well a consequence of simili- nonlinear elastic-plastic stress strain curves, is mechanics. (Similitude tude breaking in the underlining dislocation Met. Trans. breaking is a concept introduced by Kuhlmann-Wisdorf 16A, 2091 (1985) to dislocation mechanics.) 10:50 AM Invited Theory of Harper- New Predictions of the Dislocation Network Dorn Creep cation glide within subgrain interiors and dynamic recovery associated dynamic interiors and subgrain glide within cation ther- in stress, small changes relatively After boundaries. with subgrain is the interiors within subgrain of dislocations activated motion mally a thermally In this regime, deformation. of mechanism predominant enabling creep transients, thereby law can describe the activated rate data. In par- be evaluated from the parameters to various activation acti- are consistent with thermally true activation areas ticular, the recovery In contrast, dynamic of forest dislocations. vated cutting rela- deformation following the constant structure processes dominate metals and results for other FCC stress reductions. Selected tively large to follow the trends established for pure related materials are shown it is demonstrated that constant structure aluminum. In particular, and LiF at high temperatures and after small creep of pure copper with a description based on thermally stress changes is also consistent in behavior between these materials activated glide. The differences energy. in stacking fault are attributed to differences 10:10 AM Break 10:20 AM Keynote Creep Exponents, Nonlinear Monotonic Unnatural Power-Law Curves and Similitude Breaking and Cyclic Stress-Strain Johannes Weertman

TUESDAY AM 69 short rangeorder totheunderlyingelectronicstructure ofthedisor- functional approachprovidesadirect wayofrelatingclusteringand proximation (LDA-KKR-CPA) the,in principleexact,concentration sity approximationKorringa-Kohn-Rostoker coherent-potential-ap- field approximationandcombined withthefirstprincipleslocalden- Phys. Rev. Letters{\bf56},374(1983)].Whenevaluated inthemean stability developedintheearly80’s [B.L.Gyorffyand G.M.Stocks, first principlesconcentrationfunctional theoryoforderingandphase InthispaperIreviewtheorigins,successes,andlimitationsof the 37831-6114 USA Laboratory, Met.andCer. Div., P.O. Box2008-6114, OakRidge,TN Phase Stability First PrinciplesConcentrationFunctionalApproachtoAlloy 9:30 AMInvited interfaces, dislocations. deformations, coherentornot,suchassemi-coherentincoherent precipitates interactions)andwhichisabletodealwitharbitrarylocal cases, reproduceswell-knowproperties(particleshapetransitions, atomistic approach,basedonMonteCarlosimulations,which,insimple proach validforcoherentsystems.We willalsopresentageneral erties. We willdiscusstheseaspectsinacontinuousphasefieldap- tic effects,inparticulargrowthlawsofparticlesizesandscalingprop- of thecharacteristicsthesemicrostructuresaredeterminedbyelas- complex microstructures.Atamesoscopictimeandspacescale,most the coexistenceofmanydifferentphasesordomainswhichform Structuralororderingtransformationsinalloysleadgenerallyto BP72, Chatillon,Cedex92322France Monte CarloSimulations Dynamical EvolutionofOrderinginAlloys:PhaseFieldand 9:00 AMInvited variable. Thisdiscursivesurveywilllookatanumberoftheseaspects. mental andtheoretical,notmuchattentionhasasyetbeenpaidtothis distinct methodsexisttoestimatetheorderingenergy, bothexperi- some aspectsofrecrystallization.Inspitethefactthatseveral the widthofsuperdislocations,resistancetocreepunderstress,and main boundaries,thechangeinlatticeparameterwhenorderislost, of theorder-disordertransition,specificenergyantiphasedo- number ofitsproperties,includingthetemperature(actualorvirtual) Theorderingenergyofanalloywithasuperlatticedetermines England University, Matls.Sci.&Metallu.,PembrokeSt.,CambridgeCB23QZ Some AspectsofOrderingEnergy 8:30 AMInvited Angeles, CA90024USA USA; AlanJ.Ardell,UCLA,Matls.Sci.andEng.,Los University, Matls.Sci.andEng.,Pittsburgh, PA 15213-3890 Session Chairs: Room:JohnsonA/B March 14,2000 AM Tuesday CA 94551-0808USA Gonis, LawrenceLivermoreNationalLaboratory, Livermore, Technology Division,Livermore,CA94551USA;Antonios Livermore NationalLaboratory, MaterialsScienceand Program Organizers: Committee Magnetic &PhotonicMaterialsDivision,AlloyPhases Sponsored by: in Materials:SessionII Phase Transformations andEvolution Hume RotheryAward Symposium; : Structural MaterialsDivision,Electronic, David E.Laughlin,CarnegieMellon George MalcolmStocks Location: OprylandConventionCenter Patrice E.A.Turchi,Lawrence : Alphonse Finel : Robert W. Cahn 1 1 ; ; 1 1 Oak RidgeNational Onera/CNRS, LEM, 1 ; 1 Cambridge tion underL1 mation withalatticesymmetrychange,suchasthetetragonaldistor- model todescribetheinfluenceofelasticforcesonphasetransfor- great simplificationofthecalculations.We alsosuggestamicroscopic combines highaccuracyinthedescriptionofthermodynamicswith being akineticanalogueoftheknownclustervariationmethodwhich cluster methods.Inparticular,wedevelopakineticfieldmethod cal physicsincludingthekineticmean-fieldmethodand proximate methodsanalogoustothoseusedintheequilibriumstatisti- non-equilibrium alloy. To solvetheseequationsweemploytheap- and correlatorsoftheirfluctuations,aswellforthefreeenergya exact equationsforthetemporalevolutionoflocalconcentrations tion ofnon-equilibriumatomicdistributionsinanalloy. We derive equation todevelopaconsistenttheoreticaldescriptionoftheevolu- We reviewaseriesofworkswhere weusethefundamentalmaster Instit., Moscow123182Russia Transformations Equilibrium AlloysandItsApplicationstoStudiesofPhase Master EquationApproachtoConfigurationalKineticsofNon- 10:00 AMInvited poration. DEAC05—960R22464 withLockheed-MartinEnergyResearchCor- Materials Sciences,USDepartmentofEnergy, undersubcontract tions. Work supportedbyOffice ofBasicEnergy Sciences,Divisionof on alloyphasestabilitybasedlargecell(100-1000atom)simula- regarding screeninginsubstitutionallydisorderedalloysanditsaffect will placeparticularemphasisonwhatasbeenlearnedinrecentyears charge transfer, ...)thatgiverisetotheobservedorderingbehavior. I underlying electronicmechanisms(Fermisurfacenesting,bandfilling, tion metals.Ineachcasestresswillbeplacedonunderstandingthe theory andtothemagneticphasetransitioninferromagnetictransi- tration functionalmethodtoanumberofclassicalproblemsinalloy dered phase.IwillreviewapplicationsoftheLDA-KKR-CPA concen- USA burgh, Matls. Sci. andEng.,848BenedumHall,Pittsburgh, PA 15261 Polytwinned Ferromagnets Evolution ofMicrostructure andDefectStructurein 11:15 AMInvited tems. good agreementwiththeexperimental resultsintherealalloysys- tation willbedemonstrated.Theresultssimulatedarequantitatively in der phasetransitionwithdecomposition,discontinuousprecipi- strain inducedmorphologicalchangesofprecipitates,theorder-disor- such asformationofmodulatedstructurebyspinodaldecomposition, etc. Timedependentmorphologicalchangesofthemicrostructure on thelocalorderparameterssuchascomposition,degreeoforder, systems. Theelasticityandmobilityofatomsareassumedtodepend count soastobeapplicableforthephasediagramofrealalloy sition dependenciesofatomicinterchangeenergyaretakeninto ac- Fe-Al-Co andGaAs-InPbasedonthephasefieldmethod.Thecompo- microstructure changesinrealalloysystems,suchasFe-Mo,Al-Zn, ment ofcomputer. Inthepresentstudy, wecalculatethedynamicsof namics ofphasetransformationwiththerecentremarkabledevelop- become verypowerfulmethodinfundamentalunderstandingthedy- Thekineticsimulationbasedonthenon-lineardiffusionequation 8555 Japan ogy, Dept.ofMatls.Sci.&Eng.,Gokiso-cho,Showa-ku,Nagoya466- Toru Miyazaki tion inRealAlloySystemsBasedonthePhaseFieldMethod Computational InvestigationsontheMicrostructureForma- 10:45 AMInvited 10:30 AMBreak well withexperimentalobservations. of newandinterestingmicrostructuraleffects,manythemagreeing well aswithoutandwithelasticeffects.Thesestudiesrevealanumber B2, D0 tions includingthedecompositionofdisorderedalloysandorderings studies ofthemicrostructuralevolutionundervariousphasetransi- man Samolyuk 3 , L1 2 andL1 0 ordering.Thedevelopedmethodsareusedforextensive 1 1 ; ; Toshiyuki Koyama Valentin Vaks : KirillBelashchenko 0 typebothwithoutandwithphaseseparationas : 1 William A.Soffa ; 1 Russian ResearchCenter, Kurchatov 1 ; 1 Nagoya InstituteofTechnol- 1 ; VladimirDobretsov 1 ; 1 University ofPitts- 1 ; Ger- :

TUESDAY AM 70 : Missis- 1 ; 2 ; Ward Jensen ; Ward 1 Naval Research Laboratory, 1 ; 1 anal E Nancy S. Losure David L. Bourell, University of Texas, David L. Bourell, University : Location: Opryland Convention Center ; George Spanos ; George 1 Oreck Manufacturing, 21180 Oreck Blvd., Long 2 Materials Processing and Manufacturing Materials David L. Bourell, University of Texas- sippi State University, Swalm Schl. of Chem. Eng., Mississippi State, sippi State University, MS 39762 USA; Beach, MS 39560 USA Rapid prototyping techniques have traditionally been used to produce parts to validate design dimensions and assembly procedures. Stereolithographic (SLA) techniques produce parts with excellent surface finish and detail, but limited strength and problems with dimen- On the other hand, a relatively new process, Fused sional stability. Deposition Modeling (FDM), produces parts from an engineering resin, ABS, with good surface finish, much higher strength and excellent It is important that the mechanical properties dimensional stability. 8:30 AM Navy Perspective Solid Freeform Fabrication: A United States Washing- S.W., Ave. Code 6324, 4555 Overlook Matls. Sci. & Tech., ton, DC 20375 USA agencies such as ONR in cooperation with other federal government OSD and NSF has been sponsoring research in Solid Freeform DARPA, early days. These agencies Fabrication (SFF) technology since it’s and develop- have played a major role in promoting the understanding Deposition Modeling ment of manufacturing processes such as Fused Sintering (SLS), Shape (FDM), 3-D Printing (3DP), Selective Laser (SLA), Selected Area Deposition Modeling (SDM), Stereolithography and others. SFF Laser Deposition (SALD), Direct Photo Shaping various homogeneous projects have been pushed to experiment with materials and combination of materials (functionally graded materi- are finding their way into industry for customized als). Technologies prototypes and even for functional components. But theoretical and experimental work remains to be done and new opportunities in diverse areas such as electronic packaging and biomedical engineering are emerging. This talk will survey some of the projects supported by ONR and other agencies and discuss some possible Navy applications. 9:00 AM Effect of Build-Plane Orientation on the Mechanical Proper- ties of Parts Made by Fused Deposition Modeling (FDM) and by (SLA) Stereolithography International Symposium on Global on Symposium International Processing in Materials Innovations Stereolithography and Manufacturing: Sintering Laser and Selective by: Sponsored Division, Organizers: Program Department, Austin, TX 78712- Mechanical Engineering Ames Iowa State University, 1063 USA; Iver Anderson, Sears, USA; James W. Ames, IA 50011-3020 Laboratory, NY Schenectedy, Inc., D2, 114, Lockheed Martin, KAPL Sandia National Laborato- Smugeresky, 12301 USA; John E. Livermore, CA 94551-0969 USA; Dan ries, Department 8724, Materials National Laboratory, J. Thoma, Los Alamos NM 87545-0001 USA; Los Alamos, Science and Technology, Oak Laboratory, Oak Ridge National Srinath Viswanathan, The Ohio State Ridge, TN 37831-6083 USA; Rob Wagoner, of Materials Science and Engineer- Department University, ing, Columbus, OH 43210 USA Tuesday AMMarch 14, 2000 C Room: Session Chair: Austin, Austin, TX 78745 USA Cooper Khershed P. 2 1-x +L1 -Pt Com- x 0 1 ; 2 stability region, our 2 ; Armen G. Khachaturyan 1 two phase region of the Co-Pt system. 2 +L1 0 Yann M. Le Bouar Yann Rutgers University, Cer. and Matls. Eng., 607 Taylor Cer. Rutgers University, 2 : microscopic simulation explain the formation of the platelet or saw- microscopic simulation explain the formation results are in excellent tooth-like morphologies. All the simulation agreement with our experimental observation in the Co-Pt system. two phase region, our continuous simulations predict the formation of two phase region, our continuous simulations aligned in the elastically a chessboard microstructure, whose edges are of such a microstructure soft directions, and show that the coarsening entire band of the pat- is only possible with the disappearance of an L1 tern. When the concentration is close to the alloys. Depending of the average concentration, our TEM images alloys. Depending of the average concentration, towards a chessboard show that the microstructure may evolve either two computational or a platelet-like microstructure. Then, we present field kinetic equations or methods, based on the continuum stochastic a first order phase the microscopic Master Equation, able to describe reduction. No a priori transition with a cubic -> tetragonal symmetry and the sequence constraints are made on the possible configurations computer simulations are performed 2D of structural pattern. Finally, crystal. When the con- for an elastically isotropic and homogeneous middle of the L1 centration of the alloy is chosen close to the Rd., Piscataway, NJ 08855-0909 USA NJ 08855-0909 Rd., Piscataway, evolution of The understanding and control of the microstructure to synthesize advanced multiphase alloys is of critical importance last decades, the use of materials with given properties. During the enabled a detailed de- Transmission Electron Microscopy (TEM) has multiphase alloys. We scription of the microstructure of numerous during ordering in focused here on puzzling microstructures obtained the platinum-rich L1 Field and High Resolu- First, we present a series of TEM images (Dark of our Co tion images) to describe the complex microstructures The L10 family of ferromagnets are interesting magnetic materials interesting are of ferromagnets L10 family The These intermetal- of view. point and technical both a scientific from or form as stable and MnAl, FePd CoPt, FePt, include lics, which alloy composi- equiatomic of the in the vicinity phases metastable by a high are characterized tetragonal structures tions. The exhibit anisot- an “easy” c-axis and anisotropy with magnetocrystalline formation of 107-108 ergs/cm3. The in the range K1 ~ ropy constants generates in these alloy systems from the parent phase the L10 phase which have and defect structure polytwinned structure a characteristic in- the transformation mechanisms regarding important implications pa- structure-property relationships. In this volved and the resultant the microstructure and defect structure char- per, the development of structures will be discussed and related acterizing the L10 polytwinned to -> order transformation giving rise to the nature of the disorder by This work has been supported these polytwinned ferromagnets. NSF and DOE. AM Invited 11:45 in Decom- Morphologies Saw-Tooth-Like The Chessboard and posing Alloys Gif-Sur-Yvette Cea-Saclay, Atomique, DTA/SRMP, missariat a l ‘Energie France; 91191

TUESDAY AM 71 Recentworkin SelectiveLaserSinteringofmaterials attheUniver- 1063 USA versity ofTexas atAustin,Mech.Eng.,MC C2200, Austin,TX78712- Harlan Selective LaserSinteringwith Meso-ScaleFeatures 10:40 AM 10:20 AMBreak for superalloy625arepresented. conventionally processedmaterial.ResultsofSLS/HIPdevelopment cal propertiesofmaterialprocessedbySLS/HIParecomparable to oped forsuperalloy625andTi-6Al-4V. Microstructureandmechani- compared toHIPofcannedparts.SLS/HIPiscurrentlybeingdevel- reduced pre-processingtime,andreductioninpost-processingsteps ning stepandcontainermaterial,nocontainer-powderinteraction, tages ofin-situencapsulationincludeeliminationasecondarycan- or “oneofakind”highperformancemetalcomponents.Theadvan- ing andhotisostaticprocessing(HIP)torapidlyproducelowvolume turing techniquethatcombinesthestrengthsofselectivelasersinter- ing (SLS).Theapplication,knownasSLS/HIP, isalowcostmanufac- tion ofhighperformancemetalcomponentsviaselectivelasersinter- Thispaperfocusesonrecentadvancesindirectfreeformfabrica- C2200, Austin,TX78712-1063USA David L.Bourell nents viaSLS/HIP Direct LaserFabricationofHighPerformanceMetalCompo- 10:00 AM tures anddirectmanufacturing. polymer-ceramic systemsarebothusedforfabricationofgreenstruc- tional prototypesanddirectmanufacturing,thepolymer-metal polymer-polymer compositehasapplicationsinfabricationoffunc- polymer-polymer, polymer-ceramic,andpolymer-metalsystem.The tural characteristicsofthreeSLSmaterialsystemsformedbyCMA:a initial investigationintothemechanicalpropertiesandmicrostruc- microstructure inpartsproducedbySLS.Theworkpresentedisan particles viaSLSoffersthepossibilityofformingaco-continuous continuous throughouttheparticle.Consolidationofthesecomposite composite particlesmadebyacoatingprocess,bothmaterialsare ducing compositepowdersforselectivelasersintering(SLS).Unlike Cryogenicmechanicalalloying(CMA)offersanewmeansofpro- Eng., 213HoldenHall,Blacksburg, VA 24061-0237USA Kander Mechanical Alloying and Polymer-CeramicCompositePowdersMadebyCryogenic Selective LaserSinteringofPolymer-Polymer, Polymer-Metal, 9:40 AM technique forcreatingSLSpowdersusingceramicsormetals. posite morphologiesarestudiedhere,theMAprocessisalsoaviable containing co-continuousphases.Althoughpolymer/polymercom- cally alloyedpowdercanthenbeselectivelylasersinteredintoparts chanical, andelectronicpropertiesoftheblendaltered.Themechani- resulting compositepowdercanbemanipulatedandthephysical,me- time, andtemperatureoftheMAprocess,phasedomainsize process isinvestigatedinthisresearch.Byvaryingthechargeratio, phology ofmechanicallyalloyedpolymerblendsforuseintheSLS phases duringselectivelasersintering(SLS).Specifically, themor- alternative totraditionalcoatingmethodsforcreatingco-continuous Inthiswork,mechanicalalloying(MA)ispresentedasaneffective 24061-0237 USA Tech, Matls.Sci.&Eng.Dept.,213HoldenHall,Blacksburg, VA tering Mechanical AlloyingPolymerBlendsforSelectiveLaserSin- 9:20 AM duced byFDMandSLA. orientation affectsthestrengthandstiffnessofprototypepartspro- of thedimensionalaxes,inordertodeterminehowbuild-plane and impactspecimensinwhichthebuild-planeisperpendiculartoeach prototyping program.Inthiswork,wewillproducetensile,bending direction ofbuildsothatuserscanmaximizethebenefitfromarapid of prototypepartsbeunderstood,particularlywithrespecttothe : 1 1 ; Seok-MinPark ; CarlosTres Ayala Suchicital Julie PatriciaMartin 1 ; : SumanDas 1 University ofTexas atAustin,Mech.Eng., MC : 1 ; JosephJ.Beaman Jeffrey PatrickSchultz 1 ; RonaldGeorge Kander 1 ; Martin WohlertMartin 1 ; 1 Virginia Tech, Matls.Sci.and 1 ; DavidL.Bourell 1 ; JosephJ.Beaman 1 ; RonaldGeorge 1 ; : 1 Virginia 1 ; Nicole 1 Uni- 1 ; R. White SFF UsingInvertedProjectionofLiquidMetalDroplets 11:40 AM ing tosuccessfulfabricationofrefractorymetalcomponents. ders anddepositsoptimizationofDLFprocessparametersislead- has proveneffective ineliminatingporosity. Characterizationofpow- processing priortodepositionremoveorreduceundesiredelements being tracedbacktotraceelementsinthepowder. Additionalpowder precipitate powdersresultsinporositythesolidifiedproductthatis tion, precipitationprocess.DLFprocessingoftheserefractorymetal are typicallygasorwateratomized,producedbyachemicalreduc- metal powders,incontrasttomanylowermeltingpointpowdersthat machining stepsusedinconventionalprocessing.However,refractory powder consolidation,thermo-mechanicalprocessing,joining,and to thefabricationofrefractorymetalcomponentsbysavingmultiple metal inasinglestep.Thisprocessisviewedasparticularlybeneficial has beenshownfeasibletobuildlayeredcomponentsfromalmostany DirectedLightFabrication,asolidfree-formfabricationprocess, Alamos, NM87545USA Zirconia MoldsforTitaniumCasting 11:00 AM presented. of SelectiveLaserSinteringpartswithmeso-scalefeatureswillbe fully ceramiccomponents.Severalexamplesillustratingthepotential Optical micrographsshowthatholesizesof180 cial polymerbinder, infiltratedandpost-sinteredtohigherdensity. was pre-processedintosphericalparticles,lasersinteredwithasacrifi- with finefeaturesoftheorder100 sity ofTexas atAustindemonstratesthecapabilitytoproduceparts also presented. ments conducted on singleandmultipledroplets, bulkfeaturesare using projectedaluminumandsteel droplets.Theresultsofexperi- droplet approachtoSFF. Inaddition,experimentswereperformed tional manner. Thispaperpresentsanumericalanalysisofthehanging sionally controllablesidewall,than anobjectproducedintheconven- object, ourexperimentsshowthat it hasamuchsmoother,anddimen- smooth side.Asthesehanging droplets accumulatetoforanSFF and surfacetensioninteracttoproduceanelongateddroplet,with a upwards, andallowedtoimpingehangona“superstrate,”gravity chining formanyapplications.Ifhowever,thedropletisprojected often havefairlyroughorirregularsurfaces,whichrequirefinishma- difficult tocontrolprecisely. Thus,SFF partsmadeusingdroplets and wettinginvolved,however,theresultisthatpartgeometry is the droplet,dropletliquidfraction,etc.affectdegreeofspreading ing uponimpingement.Factorssuchassurfacetension,viscosity of Under theseconditions,gravityhastheeffectofcausingdropletspread- transfer ofadroplettosubstratebeneaththeoriginationsite. been developed.Withoutexception,theseinvolvetheformationand Anumberofdropletbasedfreeformfabricationtechniqueshave 1063 USA 2053 USA; Laboratory, P.O. Box2053,MD3135SRLBldg.,Dearborn,MI48121- K.Lewis Gary Solid Free-FormFabricationofRefractoryMetalComponents 11:20 AM bone wasproducedusinglaserscanneddata. ture casting.Ahalf-scalecastingmoldfortheheadofahumanfemur is lessthan10 be increasedtotwicethatofthegreendensity. Surfaceroughness(Ra) surface toaporousinterior. Theaveragedensityofthefiredpartscan placed byzirconia.Thefiredpartsshowgradedporosityfromadense sintered intothedesiredgreenshape.Thebinderisremovedandre- material, stabilizedzirconiamixedwithacopolymerbinder,islaser tivity withmoltentitaniumandthermalshockresistance.Thebase nium casting.Themoldmaterialsystemwaschosenforitslowreac- has beenusedtocreate“partiallystabilized”zirconiamoldsfortita- Acombinationofselectivelasersinteringandcolloidalinfiltration Austin, Mech.Eng.,MCC2200,TX78712-1063USA Park Burghardt 1 ; DavidL.Bourell 1 ; SankaranSubramaniam 1 ; 2 University ofTexas-Austin, SFFLab.,Austin,TX78712- 1 Los AlamosNationalLaboratory, MailStopG770,Los 1 ; JoeC.Fonseca µ m andflexuralstrengthissufficientforhightempera- 1 ; JosephJ.Beaman 1 ; RonB.Nemec 1 ; LarryJepson µ m to200 : Nicole Harlan 1 ; 1 1 University ofTexas at ; Tom N.Taylor µ m. Zirconiapowder µ 2 ; m arepossiblein 1 Ford Research 1 ; Seok-Min : 1 Dawn ; Paul :

TUESDAY AM 72 . -2 2 Ir U 191 235 L. F. : W. Ir, the Ir : Urenco ; L. G. 192 3 1 191 Malinckrodt 1 ; 3 mm for diameter of -2 Ir to at least 85% using the ; H. Rakhorst ; A. V. Sedavnykh ; A. V. Ir that is activated to 2 1 191 191 Ekaterinburg Non-Ferrous Metals Ekaterinburg Non-Ferrous 1 W.C. Heraeus GmbH & Company W.C. 2 are manufactured by radiation treat- are manufactured by radiation ; 1 192 and Vickers hardness is 240-280 kg/mm is 240-280 hardness and Vickers Engelhard-CLAL, 700 Blair Rd., Carteret, 2 D. F. Lupton D. F. 1 Ir is a much more efficient use of reactor ; 2 191 ; 1 A. V. Ermakov A. V. : Ir which is not activated. Urenco has a proprietary Ir sources play an important role in medical applica- 193 . By means of a hydrogen reduction treatment, this . By means of a hydrogen reduction treatment, 6 192 Ir Gamma-Sources Made from Enriched Ir Gamma-Sources Made from ; S. G. Tretiakova 1 192 ; M. Frericks 1 ; D. A. Toenshoff 1 Toth versus natural iridium giving the following advantages: (1) no minimum yield problem, (2) unplanned shutdowns of reactors do not jeop- and (3) longer shutdown periods of ardize the continuity of supply, reactors can be overlapped. 9:50 AM Iridium and Iridium Alloy Utilization in Ignition Devices NJ 07008 USA The high melting and boiling points, corrosion and spark erosion resistances of iridium and iridium alloys make these ideal candidates for electrodes in ignition devices for use in the hostile environment of The demands for ever increasing envi- a typical combustion chamber. KG, Heraeusstrasse 12-14, Hanau D-63450 Germany; KG, Heraeusstrasse 12-14, Hanau D-63450 used for enriching gas centrifuge technology that is extensively process gas IrF black. The ultra-fine compound is converted to high purity iridium iridium metal powder is consolidated to compact products by Heraeus. The iridium black is induction melted and then remelted under high The vacuum by an electron beam process, to ensure ultra-high purity. fine powder can also be consolidated by powder metallurgical techniques, but experience has shown this to be a less satisfactory route. As forming operations can be car- a result of the extremely high purity, ried out more readily than with conventional grades of iridium. The advantage of enriched The purity of iridium is 99.98-99.99% and the main impurities are the and the main impurities of iridium is 99.98-99.99% The purity The method of galvanoplastics group (Pt, Rh). metals of platinum It is an eco- rings, and disks). various articles (tubes, allows producing technology. and practically waste-free logically pure 9:10 AM High of Disks from for Production Experimental Technology Iridium Strength Grokhovskaya 8, Ekaterinburg Ave. Lenin Head of Rsch. Ctr., Processing Plant, The 620014 Russia Ir The sources of radioisotope should Iridium discs for this purpose in reactor. ment of iridium targets as (1) no contaminants should be contained meet hard conditions, such of discs is about 10 in the metal; (2) concavity of 0.1-0.3 mm; and (3) their edges should 1.5-3.0 mm and thickness for manufacture of these Technology not crumble after processing. is Massive iridium crystals, whose purity discs has been elaborated. at Mechanical treatment of crystals 99.9%, are used as workpieces. grain size of 5 x 10 high temperatures allows obtaining sheets with and calibrated during mm. Fine grain iridium can be stamped to discs do not crumble. An- one technological operation. Besides, these discs coating of disc edges by other way for suppressing the crumble is the aluminum. 9:30 AM Radioactive Borneman Netherlands; Petten Medical B.V., Almelo, Netherlands Nederland B.V., Radioactive and in industrial non-destructive test- tions, especially brachytherapy, with variable neutron ing (NDT). Due to the nature of nuclear reactors supply of iridium sources fluxes and sometimes unplanned shutdowns, the guarantee of a minimum has not only been under stress, but also the are made by irradiat- yield (Ci/gram) has been difficult. Current sources Natural nuclear reactor. ing natural iridium, in solid metal form, in a iridium, however, contains only 37% remainder being R&D programme for commercial nuclear power plants. A successful has adapted this technology to enrich neutrons, resulting in much smaller sources, or sources with much gains outweigh the higher These efficiency higher specific activity. costs of enrichment and pellet manufacturing. Irradiation results have verified a near doubling of specific activity of irradiated 85% of crucible corresponded to the degree of mechanical treatment of the treatment of mechanical the degree to corresponded of crucible and high plasticity has iridium The electrodeposited matrix. graphite of electrolytic Microhardness castings. as iridium density the same kg/mm is 320-340 iridium : ; G. 1 ; T. Giesel ; T. 1 atmosphere. The Ekaterinburg Non- Ekaterinburg 2 1 ; 2 ; M. Frericks 1 ; N. Saltykova Institute of High Temperature Elec- Institute of High Temperature 1 2 C. The most optimum method can be T. Loose T. ° : Evan K. Ohriner, Oak Ridge National Oak Evan K. Ohriner, Location: Opryland Convention Center Location: Opryland Richard D. Lanam, Engelhard-CLAL LP, Richard D. Lanam, Engelhard-CLAL Structural Materials Division, Refractory Materials Division, Structural ; V. E. Baraboshkin ; V. 1 W.C. Heraeus GmbH & Company KG, Heraeusstrasse 12- W.C. 1 ; 1 Ferrous Metals Processing Plant, The Head of Rsch. Ctr., Lenin Ave. Rsch. Ctr., Ferrous Metals Processing Plant, The Head of 620014 Russia; 8, Ekaterinburg Russia Ekaterinburg, trochemistry, Iridium has the high melting point and unique resistance to aggressive oxidation environments at high temperatures. It is used as container material for growing of high temperature oxide crystals. The mechanical treatment of iridium has essential difficulties because of its considerable hardness. In the Ekaterinburg Non-Ferrous Metals Pro- cessing Plant, the electrolysis was performed in the hermetic electrolyzer in argon atmosphere. The electrodeposition of iridium was carried out in the melt of eutectics of NaCl-KCl-CsCl containing iridium chlorides at 500-600 considered as the combination of the electrolytic iridium refining of metal- and non-metal impurities with the preparation of iridium articles using the method of galvanoplastics. Therefore, the dissoluble anodic material can be used not only in form of pure iridium but also as its scrap. The cathodic matrices were made of graphite having the form of articles. The anodic current density should be as low as to avoid salt passivation of iridium anode. The reversal current and the rotation of the cathode during electrolysis decreased the grain size of avoid iridium compact layer (coating) and smoothed its surface. To the appearance of the structure coating defects (excrescencies, pores) several technological procedures were used; one of which was the preliminary thermal treatment of graphite matrixes in aim to remove the gases from them. After the electrodeposition of iridium coatings onto matrix the latter was destroyed. The roughness of the internal surface 14, Hanau D-63450 Germany d.c. reactive magnetron Iridium oxide coatings were produced by Ar/O sputtering of a metallic iridium target in an properties of the deposit depend on the sputter parameters (time, properties of the deposit depend on the sputter temperature) as well as the substrate material oxygen flow, power, was used to investigate (titanium, stainless steel). Cyclo-voltametry NaCl-solution was mea- electrochemical properties. Corrosion in 0.9% potential of the sured by potentiostatic voltametry at the corrosion oxide was deter- uncoated surface. The composition of the iridium surface morphology by the mined by auger electron spectroscopy, Adherent, crack free coatings with good scanning electron microscopy. using a metallic mechanical and corrosion stability can be achieved interlayer. 8:50 AM of Molten Salts Production of Iridium Crucibles by Electrolysis N. I. Timofeev 8:30 AM Iridium Oxide Coat- Characterization of Sputter-Deposited ings for Medical Implants Session Chairs: Non- Ekaterinburg N. I. Timofeev, Carteret, NJ 07008 USA; Plant, The Head of Research Ferrous Metals Processing 620014 Russia Ekaterinburg Center, Herklotz Tuesday AMMarch 14, 2000 Room: Jackson A/B Sponsored by: Sponsored Metals Committee Organizers: Program H. Harada, TN 37831-6083 USA; Oak Ridge, Laboratory, 305 Ibaraki for Metals, Tsukuba, National Research Institute Engelhard-CLAL, Careret, NJ 07008 Japan; R. D. Lanam, Ekatrinburg Ural State University, USA; Peter Panfilov, 62001 Russia International Symposium on Iridium: Symposium International Applications

TUESDAY AM 73 their life-timein GGG is2000hoursandinAYG is800hours, while of 2mm)possess highestworkingresourcefor iridium containers: crucibles). Welding crucibles fromsinglecrystalworkpieces(wallthick welding ofcrucibles)orgalvanoplastic means(productionofjointless either traditionaltechnology(rolling ofsheets,stampingcansand 200 mminheight,thicknessofwalls is2mmcouldbemanufactured ity ofcrystals.Iridiumcontainers with sizeupto200mmindiameter, key elementofgrowingtechnology, whichdetermines purityandqual- other oxidescouldbegrown.Experience hasshownthatcrucibleisthe garnet GGG(Gd tals ofaluminum-yttriumgarnetAYG (Y Iridiumisthesolematerialforcontainers,wherelargesinglecrys- Alaxandrov, Russia Ctr., Lenin Ave. 8,Ekaterinburg 620014Russia; 1 TimofeevI. Iridium asContainerMaterialforOxideCrystalGrowing 11:20 AM of thetraditionalPt-Irandnewiridiumuseswillbeshown. surface enhancingprocessesuniquedesignscanbeachieved.Examples make itadesirablematerialforjewelry. Throughnear-netshapeand jewelry. Iridium’s propertiesofbeingveryhardandcorrosionresistant will bediscussed.Arecentdevelopmentistheuseofiridiumitselfin wear. Thecompositions andapplicationoftheplatinum-iridiumalloys addition toplatinumincreasehardnessandimproveresistance Theprincipleuseofiridiumforjewelryhasbeenasanalloying USA; Lanam The UseofIridiumforJewelry 11:00 AM yields adramaticincreaseinperformance. now beoperatedattemperatureswellinexcessof1900 and otherdefects.Usingthisarchitecture,combustionchamberscan resulting coatingisverypureandfreeofcracks,porosity, pinholes, rhenium, andCVDisthepreferredprocessingtechniquebecause tion resistance,highmeltingpoint,andthermalexpansionmatchwith interior. Iridiumisidealforthisapplicationduetoitsexcellentoxida- (typically 0.003")ofchemicalvapordeposited(CVD)iridiumonthe bers nowcomprisearheniumstructuralshellprotectedbythinfilm catastrophic failureoccurs.Currentstate-of-the-artcombustioncham- At highertemperatures,rapidoxidationofthesilicidetakesplaceand chambers typicallyoperateattemperaturesbetween1300and1400 niobium combustionchambersforapogeetoppingmaneuvers.These Mostsatellitesplacedingeosynchronousorbitrelyonsilicide-coated Pacoima, CA91331USA WilliamsE. pulsion Iridium/Rhenium CombustionChambersforChemicalPro- 10:40 AM be discussed. of properextensionwiresanddataacquisitionrecommendationswill control. Inaddition,practicalerrorconsiderations;suchasutilization temperature measurementforcrystalgrowthandindustrialfurnace will focusoncurrentapplicationssuchasgasturbineinstrumentation, higher temperaturesespeciallyunderoxidizingconditions.Thispaper becoming increasinglyimportantwiththeneedtoaccuratelymeasure of itanditsalloysinhightemperaturethermometry. Thisuseis Oneofthelessorknownindustrialusesiridiumisapplication USA Grossi The UseofIridiuminHighTemperature Thermometry 10:20 AM 10:10 AMBreak tial methodsofovercomingthem. into someoftheobstaclesencounteredinuseiridiumandpoten- incorporation andbehaviorinvariousignitiondevices,aninsight thermomechanical propertiesandprocessingofiridiummaterials,their alloys assparkplugelectrodes.Thispaperwillexaminesomeofthe mobile enginesstronglysuggesttheutilizationofiridiumand/orits ronmental andcombustionefficiencylongerservicelifeinauto- Ekaterinburg Non-FerrousMetalsProcessingPlant,TheHeadofRsch. 2 2 1 Engelhard-CLAL, 700BlairRd.,Carteret,NJ07008USA : ; ; A. J.Fortini 1 1 Tiffany &Company, 143SparksAve., Pelham,NY10803 Engelhard-CLAL, 4025ClipperCt.,Fremont,CA94538 1 1 ; J.W. Brockmeyer ; B.Dorogovin 3 Ga 5 O 1 12 ; R.H.Tuffias ), gallium-lanthanumsilicate(La 2 ; A. V. Yermakov 1 ; : 1 1 Ultramet, 12173MontagueSt., C. Volpe ; R.B.Kaplan 3 Al 5 O 1 12 ; K.Vaithinathan ), gallium-gadolinium 1 ; S.Yu. Stepanov 1 ; A.J.Duffy 3 Ga 2 VNIISIMS, 5 SiO ° C, which 14 ), and : N. : 2 1 ; R. ; B. ° C. J. 2 ; covering andrecyclingprocessesforiridiumarediscussed. and supplyassociatedwithincreasedapplicationsofiridium.Newre- minimize tremendouspricechangescausedbyimbalanceindemand additives. Highefficiencyintherecoveryiridiumisveryimportantto including microstructurecontrol,improvedpurification,andspecial difficulties inprocessingthroughthespecialtechniques succeeded indevelopingvariousmaterialsandovercoming per productionofvariousmaterialssuchasPZTandSBZ.We have consumption, isexpectedtogrowrequiringiridiumasabestcandidate superior nonvolatility, speed,andvolumerequiringlesspower spark plugs.UseofferroelectricmemorysocalledF-RAM,having mocouples, rocketparts,gas-turbineblades,glassmanufacturing,and to itshighrefractorycharacteristics,iridiumfindsapplicationinther- devices. Growthiniridiumdemandthenearfutureisexpected.Due tal growthforadvancedelectronicsdevices,YAG lasertips,andSAW total supply. Thoseincludeapplicationsofthecompoundsinglecrys- Demand fortheiridiumcruciblesandpartscomprisesabout3%of sis, chlor-alkalielectrolysis,andelectro-galvanizingamongothers. iridium demandisconsumedforelectrodesusedinindustrialelectroly- Another isintheelectrochemicalfieldwhereabout25%oftotal the newlydevelopedcatalysttoreduceautomotiveengineemission. Japan, withanincreasingvarietyofapplications.Oneapplicationis Iridiumdemandistremendouslyincreasing,especiallysince1995in Ibaraki 308-0861Japan 1 Iridium andItsApplication-Present StatusinJapan 11:40 AM ones. iridium islessthanfor“singlecrystal”crucibles,buthigher for AYG. Resourceofweldingcontainers fromelectronbeammelted lifetimes ofgalvanoplasticonesare1000hoursforGGGand120 26500, Patras,Greece High Temperature ChemicalProcesses,Forth, P.O. Box1414,GR- Trondheim N-7491 Norway; 1 Vik Fluoro ComplexesFormedinLiF-NaF-KF-Melts Solubility andRamanSpectra ofNiobium(V)FluoroandOxo 8:30 AM Matls. Rsch.,Arlington,VA 22230USA Bruce MacDonald,NationalScienceFundation,Div. of of Matls.Sci.andEng.,Cincinnati,OH45221-0012USA; Session Chairs: March 14,2000 Tuesday AM Materials Engineering,Tuscaloosa,AL35487USA Reddy, UniversityofAlabama,DepartmentMetalsand University ofChicago,IL60637USA;Ramana Madison, WI53706-1595USA;Dr. SusanMeschel,The Wisconsin, DepartmentofMaterialsScience&Engineering, nati, OH45221-0012USA;Y. AustinChang,Universityof Department ofMaterialsScienceandEngineering,Cincin- Program Organizers: Process FundamentalsCommittee Division, Thermodynamics&PhaseEquilibriaCommittee, Critical Technology Sector, Extraction&Processing Sponsored by: Session III ture ThermochemistryofMaterials: Kleppa SymposiumonHighTempera- Furuyametals CompanyLimited,1915Morizoesima,Shimodateshi, Norwegian UniversityofScience andTechnology, Dept.ofChem., 1 ; Terje Ostvold ASM International:MaterialsScience 1 ; Vassilis Drakopoulos Ray Y. Lin,University ofCincinnati,Dept. Location: OprylandConventionCenter Room: LincolnE Ray Y. Lin,UniversityofCincinnati, 2 Institute ofChemical Engineeringand 2 ; George N.Papatheodorou : : Aasmund F. T. Maruko 1 2 ; ;

TUESDAY AM 74 ; ; 1 1 sys- 4 1.0, in ≤ G. Boureau : ; Teruhisa Horita ; Teruhisa 1 University of Miskolc, 0.35 and (ii)0.45 1 ≤ ; 1 CdTe National Institute of Materials -based ceramics and perovskite- 1 2 = 0.4 establish that the system = 0.4 establish ; 1 CdTe ; Katsuhiko Yamaji ; J. Sytchev 1 1 -based ceramics, the interaction parameters for -based ceramics, the interaction parameters 2 G. Kaptay 0.45), in which the behaviour appears to be compli- 0.45), in which the behaviour ≤ ; Hideyuki Negishi 1 : Harumi Yokokawa : x CdTe x CdTe ≤ Universite Pierre et Marie Curie, Lab. de Chimie Physique, Matiere et Curie, Lab. de Chimie Physique, Matiere Universite Pierre et Marie tem has been used at 973K, under argon gas. Experiments were performed in the glassy-carbon crucible, which served as counter electrode and reference electrode, as well. Cyclic voltammetric curves were taken at different scan rates from 0.001 V/s till 10 V/s. When silver was used as cathode, a one-step, 3-electron boron deposition was observed as a reversible electrochemical process. However, when molybdenum wire was used as cathode material, several pre-peaks appeared at more positive potentials compared to deposition of B on Ag cathode. The pre-peaks are due to the formation of molybdenum between The potential difference stoichiometry. borides of different the B-peak on the Ag-cathode and between the pre-peaks observed on the Mocathode are related to the formation energies of different mo- and Chemical Research, Energy-Related Matls. Grp., 1-1 Higashi, and Chemical Research, Energy-Related Matls. Ibaraki 305-8565 Japan Tsukuba, Thermochemical properties of ZrO type oxides were analyzed so as to obtain the good correlation with type oxides were analyzed so as to obtain the determined phase ionic properties and to reproduce the experimentally relations. For ZrO calculation in the cubic phases were derived from the phase diagram properties. Those pa- absence of the experimental thermochemical rameters which were derived for respective valences of dopants show the good correlation with ionic radii of dopants. This allowed us to calculate solubility of transition metal oxides over a wide range of oxygen patential, in which the valence of the transition metal ions The calculated solubility was compared with ex- changes drastically. perimental values determined by Sasaki et al. Good agreement was obtained except for the zirconium vanadium oxygen system. AM 11:40 Formation Energies of Molybdenum Borides Measured by Voltammetry Miskolc, Egyetemvaros 3515 Hungary For measurements the molten NaCl-KCl-NaF (5 mol%)-KBF consists of two terminal regions (i) 0 < x two terminal regions (i) consists of behaviour is relatively simple. The two which the thermodynamic by a narrow transient or central region terminal regions are connected (0.35 cated. 10:40 AM Modelisation in Oxides Thermochemistry and 1 Pierre et Marie Curie, Paris, Cedex 05 75231 Rayonnement, 11 Rue France we show that the informations won from In the present paper of are essential in the understanding experimental thermodynamics of formation investigate the following fields: energy shall oxides: We (2) both, direct of defects in bulk oxides (1) and at the interfaces; of oxygen vacancies experimental investigation and ab initio studies invaluable in providing are difficult. The help of thermodynamics is (3, 4). Without any severe constraints. Ionic and electronic transport. analysis of experi- additional parameters, a purely thermodynamic electronic transport in mental data provide a good understanding of thermodynamics some particular cases (polaronic models). Statistical may have a number (5). Such an approach needs reliable inputs which to make guesses about of origins. In some cases, thermodynamics allow with micro- the nature of defects and of interactions. Comparison we shall discuss links scopic observation is particularly useful. Then in silicium oxides between thermodynamic data and charge transfer and in germanium oxides. AM 11:10 Oxide Fuel Cell Ma- Thermodynamic Considerations on Solid terials Natsuko Sakai excess stability functions. The stability and excess stability together stability and excess stability The stability functions. excess pa- stability relative excess and relative stability stability, with ideal continu- The temperatures. at different calculated have been rameters excess stability constancy of and stability Darken’s of ous variation HgTe-CdTe, that ZnTe-CdTe, composition confirm functions with of single phase field systems consist PbSe-PbTe and ZnSe-ZnTe hand, in the On the other the entire range of composition. throughout and of stability changes in the variation system, sharp CdSe-CdTe functions near x excess stability ; 3 3 1 O- 2 = 3; (s) + 5 Nb at low o = 2. 2. O 2 2- O-MoO Nb 7 2 O-MoO o 2 R. Ferro O/n o C has been C has ° : melt in the O/n 3 o + Nb was dissolved. + in the melt as 3 2- -alumina Na and temperature β 3 O concentration in O concentration . 2 -1 C), and the dissolu- ° -alumina as the solid K in FLiNaK was mea- O-MoO 5 (s) previously formed -1 S(s) β was formed upon fur- 2 3 2 3- O 4 2 F was formed; n 2 3 system was studied using a 3 C to 800 M.L., Dept. of Matls. Sci. and ° 1 ; 2 for the reaction (based on concen- for the reaction (based (g), Pt(s)Na O in the Na 2 2 O-MoO < 2; all Nb (V) and O < 2; all Nb sol solubilities were observed. The struc- solubilities were observed. 2 ° Banaras Hindu University, Instit. of Banaras Hindu University, 2- Nb 1 o O in the melt was evaluated from the 2 ; 1 O/n o (s). H 3 , the following observations were recorded at observations were , the following 7 was increasing. NbO : 1. n Nb ; John F. Elliott ; John F. Nb o ) was found to be 89 kJmol 1 o metals, their thermodynamics of reaction with the -1 NbF 2  O/n O/n o Universita degli Studi di Genova, Dept. di Chimica e Universita degli Studi di Genova, Dept. di Chimica o 1 K + AlkNbO octahedra. The solubility of Nb octahedra. The solubility 6 -1 3- 4 ; < 3; a solid of the type AlkNbO < 3; a solid of the type 1 M. Shamsuddin F 2 Nb Ray Y. Lin Ray Y. o : when n : University of Cincinnati, Cincinnati, OH 45221 USA University of Cincinnati, Cincinnati, OH 45221 2- 2 melt. The activity of Na 5 O/n 3 o = NbO - Tech., Dept. of Metallu. Eng., Varanasi 221-005 India Dept. of Metallu. Eng., Varanasi Tech., In recent years thermodynamic measurements on several HgTe- ZnTe-CdTe, pseudobinary chalcogenide systems, viz. CdSe-CdTe, using fused salt gal- and PbSe-PbTe and PbSe-PbTe ZnSe-ZnTe CdTe, vanic cell technique have been conducted. Thermodynamic data show that these systems do not follow regular solution model and also do not formalism. Hence thermodynamic behaviour of these satisfy Darken’s stability and systems have been analyzed in the light of Darken’s Chimica Industriale, Via Dodecaneso, Genova 31-16146 Italy Chimica Industriale, Via In the framework of a description of the general alloying behaviour of the rare earth MoO was also evaluated a function of temperature and melt composition from the Na from the Gibbs-Duhem equation with the help is reviewed. Also 15th and 16th group elements of the Periodic Table on the basis of our obtained laboratory results, special attention is given to the thermochemistry of formation of the arsenides, antimonides, bismuthides, selenides and tellurides of the R elements. The properties of these substances are also discussed and compared with those of compounds formed by other transition elements similar to the R metals (actinides, etc.). Problems met in the thermochemical characterization and in the experimental investigation of this family of substances are finally highlighted and discussed. 10:00 AM Break 10:10 AM Thermodynamic Investigations of Pseudobinary Chalcogenide Systems phase diagram. 9:30 AM of the Rare Earth Comments on the Formation Thermodynamics Clements Compounds with the 15th and 16th Group a minimum in the Nb (V) and O a minimum in the Nb (V) to be given by the reaction: Alk tion mechanism seems 9:00 AM Study of the Na Electrochemical High Temperature Eng.; Physical chemistry of the Na high temperature electrochemical cell with Na, mixture of tungsten, electrolyte. The reference electrode is a solid may be expressed as the tungsten sulfide and sodium sulfide. The cell following. W(s), WS2(s)| Na+| O MoO composition range from 50.87 to 92.18 mol% this cell. Partial molar from 890 to 1230 K was determined using enthalpy of mixing for Na G. Borzone System ture of the species in the melt was not easy to establish due to a very ture of the species in the < r < 4; the AlkNbO weak Raman signal. 3.3 trations in mole kg the Gibbs-Helmhotz temperature dependence of the activity data using reported in the literature equation. The value agrees well with those of MoO from calorimetric measurements. The activity The Raman spectra indicated the presence of monomeric NbF of monomeric spectra indicated the presence The Raman and was the dominating specie at n ther additions of oxide the formation of both corner and edge sharing dissolved, possibly with distorted NbO temperature (550 sured as a function of 4F The solubility of Nb (V) as a function of the Na as a function of Nb (V) solubility The at 700 melt (FLiNaK) LiF-NaF-KF eutectic the ternary and concentrations oxide at different Raman spectra The determined. of melt analysis on chemical Based also recorded. were temperatures to the Nb- bands, suggestions related the observed Raman samples and containing are given. In FLiNaK formed in the melt O-F complexes 0.22 mole kg melt + the to niobium in the molar ratios of oxygen varying total n solids formed, which reacted with oxide to form monomeric oxide concentrations, NbOF 2 < n

TUESDAY AM 75 3515 Hungary ingots asfeedstock fordiecastings,numerousstudies havebeencon- Aspartofaninternationalprogram toqualifymagnesiumalloy Hills, MIUSA Hills, MI48335-5718USA; 1 tions inMagnesiumAlloys Observations ofIntermetallic Particle andInclusionDistribu- 8:55 AM porosity canbetightlycontrolled. mine itsusefulnessforspeciallycastsampleswherechemistryand oxide inclusionsiningots.Furtherworkwouldbenecessarytodeter- ity, itisunlikelythatconductivitycouldbeusedtodirectlymeasure crease inporosity. Givenitssensitivitytobothchemistryandporos- tivity; specifically, conductivitiesdroppedabout3%foreach1% in- measurements. Increasesinporosityalsocauseadecreaseconduc- AM60B) andthehigh-aluminumAZ91Dalloy, usingconductivity distinguish betweenthelow-aluminumAM-typealloys(AM50Aand This dependenceonchemistryislargeenoughtomakeiteasy to level produceda6-8%decreaseintheconductivityofsamplesstudied. variables governingconductivity. A1wt%increaseinthealuminum num concentrationandmicrostructuralporosityaretwoimportant impact ontheconductivityofmagnesiumdie-castingalloys.Alumi- report revealthatothermicrostructuralfeaturesalsohavealarge bedded intheconductivematrix.However,resultspresentedthis potential ofdetectingtheelectricallyinsulatingoxideparticlesem- a fastandsensitivemeansofnondestructiveevaluationthatoffersthe matrix (magnesiummetal).Electricalconductivitymeasurementsare between thepropertiesofembeddedoxideparticlesandthose metal cleanliness,allofwhichseektotakeadvantagedifferences Magnesiummetalsuppliersuseavarietyofmethodstoestablish Rd., Warren, MI48090-9055USA R&D Center,Matls.&Process.Lab.,MC480-106-224,30500Mound ing Alloys Conductivity MeasurementsonIngotsofMagnesiumDie-Cast- 8:30 AM Rsch. Labs.,Dearborn,MI48121-2053USA Session Chair: March 14,2000 Tuesday AM Association, McLean,VA 22101USA 60439-4815 USA;ByronB.Clow, InternationalMagnesium John N.Hryn,Argonne National Laboratory, Argonne, IL Corporation ofAmerica,SaltLakeCity, UT84116 USA; Program Organizers: Committee, InternationalMagnesiumAssociation Sponsored by: tive IssuesandRecycling Magnesium Technology 2000:Automo- Yaghmaee Equilibrium intheLiquidFe-Al-NSystem 12:10 PM metric resultof[3]. given ontheMo-Bphasediagram,andtakingintoaccountcalori- mated byususingourvoltammetrydatacoupledwithinformation Thermodynamic propertiesofallmolybdenumborideshavebeenesti- close tothecalorimetricresultsobtainedbyMeschelandKleppa[3]. lybdenum boridephases.Calculationsproved,thatourresultsarevery Climax ResearchServices,39205 Country ClubDr., C-40,Farmington Abstracttextnotavailable 1 : ; G.Janosfy Carlton D.Fuerst Light MetalsDivision,Reactive Gerald S.Cole,FordMotorCompany, Ford 1 ; Location: OprylandConventionCenter Room: BayouC 1 University ofMiskolc,Egyetemvaros Howard I.Kaplan,Magnesium : 2 Daimler ChryslerCorporation,Auburn 1 John M.Tartaglia ; CameronJ.Dasch : 1 ; JohnC.Grebetz G. Kaptay 1 ; 1 General Motors 1 ; M.S. 2 ; Dörsam Magnesium Melting/CastingandRemeltinginFoundries 9:45 AM garding theapplicabilityofmethodasarecyclingprocess. and thetypesofinclusions.Acriticalassessmenthasbeenmadere- aided withmicroanalysiswereusedtodeterminethesize,distribution the crosssectionofbillets.Lightandscanningelectronmicroscopy understand theireffectsonthedistributionofinclusionsthroughout subsequent removal.Centrifugalcastingparameterswerevariedto inclusions intheouterskinsofbilletsduringcentrifugalcastingfor part oftherecyclingtechnology. Thegoalwastoconcentratethe magnesium alloyAZ91scrapbyutilizingcentrifugalcastingprocessas This studyhasbeenundertakentoassessthefeasibilityofrecycling opment ofaneffectiverecyclingtechnologyformagnesiumscrap. chemistry beforeitcanbereusedforcasting.Thisrequiresthedevel- ing ofscrapmetalandremovalinclusionsaswelladjustingthe sium industry. Recyclingofmagnesiumalloysnecessitatestheremelt- indicate thatrecyclingwillsoonbecomeanintegralpartofthemagne- Thetotalproductionandconsumptionfiguresofmagnesiummetal Matls. Grp.,P.O. Box21,Gebze-Kocaeli41470Turkey 1 Alloy Scraps Utilization ofCentrifugalCastinginRecyclingMagnesium 9:20 AM will bepresentedinthistalk. the particlesandsurroundingmatrix.Severalexemplarycasestudies ergy dispersivespectroscopytocharacterizetheelementalcontentof volume fractionandsize;scanningelectronmicroscopyen- tions; automatedopticalimageanalysisforquantifyingtheparticle cal macrographyandmicrographytodocumenttheparticledistribu- in surfacedefectregionssuchasfolds.Thestudieshaveincludedopti- and inclusionsdistributedthroughouttheingotbulkconcentrated recycled ingots.Thestudieshavefocusedonintermetallicparticles ducted onthemicrostructuresofAM50,AM60,andAZ91virgin 10:10 AMBreak diecasting. brief, especiallyforthetrendylarge castingpartsinhighpressure well aseconomicalandenvironmental aspectswillbedescribedin minimize therespectivespacerequired forthefurnacesareshownas furnace serieswithoptimizedhandlingsystemsandgeometricsizes to which isgettingmoreandimportant.Newdevelopments of casting machinesandforliquidchargingtowardsthepouringfurnaces expected, asforexamplethe“inhouserecycling”plantwithingot scribed andapreviewisgivenaboutthedevelopmentswhichareto be tube orinanothercastingform.Existingremeltingplantsarede- the fillingchamberofdiecastingmachinebymeanscasting The desiredcastingquantitiescanbepresetandarecasteddirectlyinto and Dynarad.Castingquantitiesof0.5to30kgpershotarepossible. from thepracticalcastingisgiven,especiallythoseNorskHydro magnesium pumpsavailableonthemarketwithexperimentalvalues gas intothefurnacetocovermagnesiummelt.Asurveyof the be added.Thus,itispossibletoconstantlymixthedesiredprotective Normally, dryairismixedwithSF6orSO2.CO2asthirdgascanalso to threedifferentmediumsinapreviouslyexactlydefinedrelation. mixed gascontrolcabinetenablesthemixturewithoneanotherofup magnesium perhouratanaverageingotsizeof8kgarepossible.A accordance tothecastingcapacity. Throughputsofupto1000kg takes placeandanautomaticchargingintothecruciblefurnacein ingots whichcanbeappliedbyhandinaferry‘swheel.Apreheating different dimensionsareavailable.Thecapacityis,forexample,36 is chargedintoaliquidmelt.Unitsforchargingofingotswiththemost ing andchargingmachinesisshownwhichpreventthathumidmaterial quent castinginingotmoulds.Theapplicationofmodernheat- mostly usedasmeltingfurnacesforcleanrecyclingmaterialsubse- hour. Tiltable, gas-heatedfurnacedesignsarealsoavailablewhich 100 to5400kgatmeltingcapacitiesof1500magnesiumper Newfurnacesandcastingplantsaredescribed,havingacapacityof Mainz-Kastel, Postfach5909,Weisbaden D-65049Germany Tubitak-Mam, MarmaraRsch.Ctr., Matls.andChem.Tech. Instit.- 1 ; 1 StrikoWestofen GmbH,Lorenz-Schott-Strasse5,D-55252 : A. ArslanKaya 1 ; SerdarSevik 1 ; HavvaZeytin : Horst 1 ;

TUESDAY AM 76 University 1 ; 1 J. Fraser Forbes : Concurrent Technologies Corpora- Concurrent Technologies 1 ; 1 Koushik Ray : tion, Matls. Eng. Grp., 100 CTC Dr., Johnstown, PA 15904 USA Johnstown, PA tion, Matls. Eng. Grp., 100 CTC Dr., Military Specification testing requirements dictate that mechanical properties of large castings and forgings are to be examined at a particular depth (for e.g. at a depth of 3" for a 12" thick casting). The experimental method for determining the heat-treatment parameters to produce optimum mechanical properties, by uniquely heat-treating several identical blocks, is impractical for economic and material handling reasons. This paper describes a method in which Finite Element Analysis (FEA) is used to determine the heat treatment required to of Alberta, Chem. and Mat. Eng., 536 Chem. Mineral Bldg., Edmonton, of Alberta, Chem. and Mat. Eng., 536 Chem. Alberta T6G2G6 Canada has evolved signifi- The meaning of the term “process control” industries in cantly since its widespread use began in the manufacturing process control applications has the scope of Further, the 1940’s. of industries using pro- drastically increased both in terms of breadth integration of these cess automation technologies and the vertical evolution and integration This technologies within a single industry. manufacturing industries of process control technologies within the automation is an integral has proceeded to such an extent that process will examine the current part of modern business practices. This paper process regulation status of process control technology from simple business planning. Each through process performance optimization to will be discussed both in stage of the operations automation hierarchy terms of the current state-of-the-art and the directions in which these technologies are evolving. The key tools and tasks necessary for success at every level of the automation hierarchy will be introduced. the the critical challenges that must be faced in accomplishing Finally, goal of complete Computer Integrated Manufacturing (CIM) will be practical although this paper addresses issues of described. Finally, the discussions will be importance to any manufacturing company, framed in terms of the particular challenges facing and the opportunities available within the materials manufacturing industries. 10:00 AM Break 10:10 AM for Large Castings Techniques Optimizing Heat Treatment and Forgings Structural optimization programs are often used to design products to design often used are programs optimization Structural displacement, on stress, to constraints subject weight for minimum in each and iteratively; are solved problems optimization etc. These 2) are performed, analyses finite element 1) the appropriate iteration of are evaluated, 3) the sensitivities constraint functions the cost and algo- 4) a nonlinear programming are computed, and these measures update necessary, check and, if to perform a convergence rithm is used generally These algorithms and initiate another iteration. the design conver- to attain such desirable a few iterations. However, converge in be avail- information must accurate sensitivity gence characteristics, re- optimization is for structures whose able. The aforementioned Unfortunately, the theory of linear elasticity. sponse is governed by To cannot be modeled with linear theories. manufacturing processes we may use the same iterative optimiza- design such nonlinear systems above. However, the nonlinear analysis and tion algorithm discussed the facilitate analysis are more complex. To subsequent sensitivity problems, the analysis and sensitivity analy- treatment of such design the nonlinear system. It is shown that sis are derived for a general that is required to perform the sensitivity analysis computational demand of that which is required to perform the actual is only a small fraction examples are provided to illustrate these meth- analysis. Three specific of a polymer extrusion die is designed to mini- ods. 1) The geometry time variations over the outlet. A Hele- mize velocity and residence the melt through the thin Shaw analysis is used to model the flow of 2) An element-by-element discontinuous Galerkin method is cavity. during the quench used to simulate precipitate nucleation and growth the subsequent optimiza- process of an aluminum alloy extrusion. In to control distortion and tion, the process parameters are determined shape in an aluminum the size distribution of precipitates. 3) The die The steady-analy- drawing process is designed to minimize distortion. which the displacement sis is modeled using a novel mixed method in unknowns. and internal field variables appear as the primary 9:20 AM Keynote Process Control: From PID to CIM Noranda 1 ; 1 Daniel Anthony : ; Don Argo ; Don 1 General Motors Research and 1 ; 1 Randy Sheng Randy : Vaughan Voller, University of Voller, Vaughan Alan A. Luo Room: Lincoln A Location: Opryland Convention Center : Vaughan R. Voller, University of Minne- R. Voller, Vaughan Extraction & Processing Division, Materials University of Illinois at Urbana-Champaign, Dept. of 1 ; 1 8:30 AM Opening Remarks 8:40 AM Keynote Optimization of Manufacturing Processes Green St., Urbana, Mech. and Indust. Eng., Mech. Eng. Bldg., 1206 W. IL 61801 USA Tortorelli Tuesday AM Sponsored by: Jt. Processing Processing and Manufacturing Division, Modeling Analysis & Control Committee Organizers: Program Minneapolis, Minnesota, Saint Anthony Falls Laboratory, MN 55414-2196 USA; Hani Henein, University of Alberta, Edmonton, AB T6G 2G6 Canada; Sulekh Jain, Ge Aircraft Engineering, MId M-89, Cincinatti, OH 45215 USA March 14, 2000 Session Chairs: sota, Civil Engineering, Minneapolis, MN 55455 USA; Hani and Process. Matls. Henein, University of Alberta, Adv. Lab., Edmonton, Alberta T6G2G6 Canada Materials Processing in the Computer Materials Processing in the and Age III: Process Optimization Control Technology Centre, 240 Hymus Blvd., Pointe-Claire, Quebec H9R1G5 Quebec Pointe-Claire, Hymus Blvd., Centre, 240 Technology Canada in developing significant efforts Noranda has made Since 1993, and process wheel casting simulation the area of aluminum expertise in at wheel casting machine a counter-pressure Recently, improvement. cast modified to Center was successfully Technology Noranda Inc. such as the cycle necessary process data supply wheels. To magnesium simulations of the casting model intensity, time and the mold-cooling using different magnesium alloys. The model process were carried out of to aluminum alloy A356, the casting results revealed that compared more process optimization. The lower volu- magnesium wheel requires an magnesium alloys is more likely to cause metric heat content of re- premature solidification in the wheel-rim over-cooled mold and to long solidification path from the wheel rim gion. Furthermore, the mold-temperature distribution to main- the hub requires an optimized solidification pattern. A carefully determined tain a directional wheel mold cooling process is therefore needed cycle time and programmed operation and to produce sound magnesium to obtain a stable casting wheels. 10:45 AM of Magne- Materials Comparison and Potential Applications sium in Automobiles Rd., P.O. Matls. & Process. Lab., 30500 Mound Development Center, MI 48090-9055 USA Box 9055, Mail Code 480-106-212, Warren, performance, mass In this paper, the material properties, structural characteristics of magne- saving potentials, design and manufacturing materials such as cast sium are compared against various competing The current and iron, steel sheet, aluminum alloys and polymers. are reviewed, and the potential automotive applications of magnesium also discussed. Recent technical challenges for these applications are and the creep resis- alloy development for powertrain applications are critically reviewed. tance of several experimental magnesium alloys magnesium in automo- Generic R&D needs for expanding the use of biles are given at the end of the paper. 10:20 AM 10:20 Magnesium of Noranda’s Modeling and Solidification Filling Process Casting Wheel

TUESDAY AM 77 online simulation andcontrol.Issuesinvolvedwith thesacrificeof model wasthenstreamlined intoareal-timemodel that canbeusedfor ness, steelchemistry, andpouringambienttemperatures.This secondary spraycoolingwaterflow ratesandtemperature,slabthick- solidification conditionsasafunction oftime-varyingcastingspeed, of thecasterwasdeveloped.The modelcomputesslabthermaland slower thanreal-time,two-dimensional transientheattransfermodel tinuous steelslabcasterisdescribed. First,ahighlyaccurate,though Acomputationalmodelforonlinesimulationandcontrolofacon- SC, IowaCity, IA52242USA Christoph Beckermann a ContinuousSteelSlabCaster Development ofaModelforOnlineSimulationandControl of 11:10 AM optimum designandoperatingconditionsarediscussed. of electrodes,thicknessslaglayerandsoon,wasevaluated.And the (including accretion)andscale,electrodesconfiguration,immersedepth adopted, andtheeffectofvariousconditions,suchasfurnaceshape method. Inthisstudy, themodel waspartiallymodified,k- and fluidflowanalysis,tracersimulationtheparticletracking furnace. Themodelconsistedof4modules,electricfieldanalysis,heat developed anumericalmodelforsimulatingphenomenaintheCL- of theCL-furnaceshouldbeoptimized.Inpreviousstudy, we minimize powerconsumption,thedesignandoperatingconditions furnace). Inordertoimprovetheseparationofslagandmatte rated continuouslyinanelectricfurnace(slagcleaningfurnace,CL- cess, slag/mattemixtureoverflowedfromasmeltingfurnaceissepa- IntheMitsubishiContinuousCopperSmeltingandConvertingPro- 8508 Japan tion, Cent.Rsch.Instit.,1-297Kitabukuro-Cho,Omiya,Saitama330- Nozomu Hasegawa ishi ProcessbyUsingNumericalHeatandFluidFlowAnalysis Optimization ofContinuousSlag/MatteSeparationinMitsub- 10:50 AM and TiAlalloys. cesses forisothermalandnonisothermalcompressionofcarbonsteel application ofthisoptimizedapproachtocontroltheforgingpro- for metalsforming.Numericalresultswillbepresentedtoillustratethe tion canselectivelycontrolledsoastoachieveanoptimizedcondition ties suchasgrainsizedistributionandrecrystallizationvolumefrac- distribution, strainrateanddeformationmicrostructuralproper- approach, thethermomechanicalfieldvariablessuchastemperature that isusedbyaNewtonbasedoptimizationmethodology. With this cesses. Thiscoupledfiniteelementmodelthenformsasacoremodule senting themicrostructuredevelopmentduringmetalsforgingpro- coupled withamicrostructurematerialsmodelthatiscapableofrepre- applied totreatthepressurefield.Thefiniteelementmodelisstrongly solve therigidplasticdeformationproblemswithpenaltymethod code forthesolutionofnon-Newtonianfluidflowandheattransferto ment modelisdevelopedbasedonthemodificationofourin-house crostructure formationduringmetalsformingprocesses.Afiniteele- approach tothecontrolofthermomechanicaldeformationandmi- Thispaperpresentsafiniteelement-basednumericaloptimization ern University, Mech.Eng.,BatonRouge,LA83808USA University, SchoolofMech.Eng.,Pullman,WA 99164USA; Liming Zhang tion andMicrostructureDevelopmentduringMetalForming Optimization andModelingofThermomechanicalDeforma- 10:30 AM for apredictedheattreatmentisalsoincluded. mechanical propertiesofeachtheslices.Experimentalvalidation number ofpossibleheattreatmentscanbestudiedbyevaluatingthe the thermalresponsesfordifferentslices,consequencesofalarge on thelargeblockusingFEA,andexperimentallymatchingeachof By generatingthermalresponseprofilesfordifferentheattreatments same thermalresponseasifitwerewithinthematerial,atthatdepth. matched forathinsliceoftheblockmaterial,sothatitreceives generated usingFEA.Thisthermalresponseisthenexperimentally thermal responseforaheattreatmentatgivendepthintheblockis obtain theoptimummechanicalpropertiesatagivendepth.First, 1 ; BenQ.Li 1 ; Akira Kaneda 1 ; 1 University ofIowa,Dept.Mech.Eng.,2412 1 ; RezaA.Mirshams : RichardA.Hardin 1 ; 1 Mitsubishi MaterialsCorpora- 2 ; 1 Washington State ε 1 ; KaiLiu modelwas 2 South- 1 ; : : Intelligent Sys.,Jamova39,LjubljanaSI-1000Slovenia; Askerceva 6,LjubljanaSI-1000Slovenia; Casting ofSteel ApproachAn Interdisciplinary Towards OptimalContinuous 11:30 AMInvited sired profileisdemonstrated. control forpreventingsurfacetemperatureexcursionsfromthede- trol isdescribed.Theuseandeffectivenessofdynamicspraycooling real-time, simulation-basedalgorithmforsecondaryspraycoolingcon- profile andthesolidificationendpoint.Finally, thedevelopmentofa effects oftransientchangesincastingvariablesontheslabthermal sults ofparametricstudiesarepresentedthatprovideinsightintothe using acalibrationprocedureforthespraycoolingcorrelations.Re- temperatures foractualcasteroperatingconditionsisachievedby interface isprovided.Goodagreementbetweenmeasuredandpredicted puter-caster hardwareinterfaceandthemulti-threadedgraphicaluser face throughthecaster’s Level1system.Anoverviewofthecom- mented onaWindowsNT-basedcomputerwithanonlinedatainter- detail inthereal-timemodelareaddressed.Thiswasimple- slab castersarepresented. (stainless steel)andNovaHut,CzechRepublic(microalloyed cal metallurgicalcriteria.ThecasestudiesfortheACRONI,Slovenia transfer modeloftheprocessandextractingvaluesempiri- lection andvariation.Solutionsareevaluatedbyrunningtheheat a randomsetofsolutionsanditerativelyimprovesthemthrough se- tically byapplyingtheprinciplesofbiologicalevolution.Itstartswith employed. Thealgorithmexploresprocessparameterssettingsheuris- the strand.To solvetheoptimization problem,ageneticalgorithmis criteria evaluatedfromthesteady-statetemperaturedistributionof minimization problembasedontheanalyticalformofcooling problem offindingoptimumcastingparametervaluesisstatedasa internal, longitudinalandtransversalsurfacecrackingpossibility. The unbending region.Thecriteriaensurethecastersafetyandlimit viation atgivenaxiallocation,andminimumsurfacetemperature recommended surfacecooling/reheatingrate,temperaturede- mum allowedlengthofliquidpool,recommended seven empiricalmetallurgicalcriteria.Thecriteriaincludethemaxi- water ontherolls,andradiation.Thequalityofslabisrelatedto mode, steelgrade,waterorair-mistspraytype,runningwater,trapped casting speed,temperature,powder,moldoscillation spray, androllheattransfercoefficients bycopingtheeffects ofthe cooling relyoncombinationofthegenericandplantspecificmold, IDS solidificationanalysispackage.Boundaryconditionsforthestrand volume enthalpyscheme.Thesolutionprocedureiscoupledwiththe The modelissolvedbytheoperator-splittingCrank-Nicolsonfinite sidered throughenhancedthermalconductivityoftheliquidphase. for theconvective-diffusiveheattransport.Fluidfloweffectsarecon- ture distributionreliesontheclassicalmixturecontinuumformulation optimization algorithm.Thephysicalmodelofthestrandtempera- transfer modeloftheprocess,empiricalmetallurgicalcriteria,and in thecontinuouscastingofsteel.Thesystemconsistsheat tational systemforautomatedsettingofoptimizedcastingconditions Thispaperdescribesmainelementsandpracticaluseofthecompu- Czech Republic University ofBrno,HeatTrans. Lab.,Technicka 2,BrnoCZ-61669 Raudensky 3 ; 1 University ofLjubljana,FluidMech.andThermo., : Bozidar Sarler 1 ; BogdanFilipic 2 Jozef StefanInstitute,Dept. 2 ; Miroslav 3 Technical

TUESDAY AM 78 ; 1 ; J. 1 North- 1 ; 1 ; R. Presthus 1 Won Kyoung Choi Won G. Ghosh ; 1 : Binghamton University, Phys- Binghamton University, 1 ; C from 30s up to 10hrs followed C from 30s up to 10hrs 1 o ; R. R. Chromik 1 Hyuck Mo Lee : ; J. Tova 1 ; A. Zribi 1 C for 100, 400 and 800hrs. The initial formation of C for 100, 400 and 800hrs. o ; L. Zavalij 1 ) which was generated when the IMC formed in the ) which was generated m H Eric J. Cotts ∆ : ; K. Teed 1 Korea Advanced Institute of Science and Technology, Dept. of Matls. Dept. and Technology, Institute of Science Korea Advanced Clum western University, Dept. of Mat. Sci. and Eng., 2225 N. Campus Dr., western University, Evanston, IL 60208-3108 USA interface, both The intermetallic formation at the solder/substrate role in determining the during processing and in service, play a key joints. Even though Pb- mechanical property and reliability of solder due to various industry, Sn eutectic solder is widely used in electronic of Pb-free solders. Fur- reasons there is a growing interest in the use solders having a thermore, electronic packaging paradigm requires size decreases and the hierarchy of melting points. As the solder joint increases, the issue of service temperature of the advanced products critical. Metallization interfacial reaction kinetics becomes very popular in elec- schemes using Ni and Pd are becoming increasingly of interfacial will present a comparative study tronic packaging. We Pb-Sn, Ag-Sn, Bi-Sn reaction kinetics in diffusion couples between The evolution of eutectic solders and Cu/Ni/Pd metallization scheme. reactions will be microstructures due to both liquid- and solid-state are characterized by presented. The products of interfacial reaction will be dis- SEM, TEM, and AEM. The interfacial microstructures isothermal sec- cussed in terms of diffusion paths using the calculated tions of the relevant ternary system. 9:50 AM Inter- Solder-Metallization Interdiffusion in Microelectronic connects Parkway East, Binghamton, NY Box 6016, Vestal ics Dept., P.O. 13902-6016 USA The reliability of solder joints is in large part determined by the nature of the intermetallic compounds which form at the solder/metal rates While dissolution interface, their stoichiometry and geometry. of eutectic Pb-Sn solder on Cu substrates are fairly well known, the solder/substrate combinations of different and integrity, solderability, has become an issue. For instance, the increased use of Pd lead finishes, or the use of electroless Ni metallizations, or the increased interest in Pb free solders, creates the need for an increase in the scope of char- of the report on our study acterization of solder/metal systems. We rates of intermetallic compound formation in solder-metallization systems, and the mechanical integrity of specific solder-substrate combinations such as (Pd; [Ni-P]; Pd/[Ni-P], Au/[Ni-P], Au/[Ni-P]/Cu) characterize the substrates in combination with Sn or [Sn-Pb]. We reaction mechanisms and constants for new phases (such as intermetallics) during short and long term aging, with a view to understanding carried out tests of reactivity (dissolution failure mechanisms. We rate) between various substrate materials and solder alloys using differential scanning calorimetry (DSC). Reaction products were character- analysis, optical and electron metallography, ized by x-ray diffraction focused on We and cross-sectional transmission electron microscopy. the reactions which produce alloys shown in mechanical testing to quantify reactivities compromise the integrity of the solder joints. We growth kinetics for the reactions with the three different solders will solders the three different with the reactions kinetics for growth the Cu substrate, with the reactions to similar Compared be presented. slower. magnitude an order of are about Ni substrate with the reactions be com- will three systems in these evolutions The microstructural compared. energies will also be The activation pared and discussed. Invited 9:10 AM Alloy on Sn-3.5wt%Ag Solder Phenomena of the Interfacial the Ni Substrates the Cu and 1 305-701 Korea 373-1, Taejon Yusung-Gu Sci. and Eng., Kusung-Dong the of the Sn-3.5wt%Ag solder alloy on The interfacial phenomena were investigated during soldering and aging. Cu and the Ni substrates at 250 The soldering was performed by aging at 130 been found to exert an effect on the growth IMC after soldering has during aging. The morphology of IMC formed and morphology of IMC the was closely related with the change of in the soldering reaction enthalpy ( liquid phase of solder. 9:30 AM Microstructure in Diffusion Couples Kinetics of Interfacial Metallization between Solder and Cu/Ni/Pd ; : 2 National Central Polly Hopkins 1 : ; 1 Sandia National Laborato- 1 ; 1 with the layered structure. The 4 C. Robert Kao Sn 3 ; 1 Hareesh Mavoori, Bell Laboratories, Hareesh Mavoori, Bell Room: Lincoln D Convention Center Location: Opryland ; C. E. Ho 1 ; Kenneth Erickson 1 Sandia National Laboratories, P.O. Box 5800, MS Sandia National Laboratories, P.O. Martin Wieser, AlliedSignal, Plated and AlliedSignal, Plated Martin Wieser, 2 Electronic, Magnetic & Photonic Materials Magnetic & Photonic Electronic, ; C. Chen 1 University, Dept. of Chem. Eng., Chungli, Taiwan University, The nickel layer with a thin Au coating is a very common surface coating reacts the Au finish in electronic components. During reflow, with the solder very rapidly and then disappears into the solder, expos- solder to The Ni layer will then react with the ing the Ni layer below. solid- the form intermetallic compound at the interface. In this study, state reactions between the 37Pb63Sn, 14Bi43Pb43Sn, 58Bi42Sn solders and the Ni substrate were investigated at several temperatures. Aging time as long as five months was used. It was found that in all cases the reaction product was Ni 0834, Albuquerque, NM 87185-0834 USA (HMC) electronics Solder joints in hybrid microelectronic circuit noble metal thick film are formed between the solder alloy and the the ceramic. The noble conductor that has been printed and fired onto reactions with Sn or metal conductors is susceptible to solid-state or more intermetallic other constituents of the solder, forming one because of the inherent porosity of compounds (IMC). Unfortunately, cannot be well pre- thick film conductors, IMC growth in conductors a quasi-one-dimensional dicted by simply applying growth kinetics to A previous paper summarized initial 2-D modeling layer geometry. work. In the results from coupled experimental and computational porous substrate-solder present paper, 3-D intermetallic growth in a determined experi- system has been modeled using a 3-D pore structure cross sections. mentally by digitizing successive 2-D metallographic The effects of the two-phase solder field in the 63Sn-37Pb/76Au- 21Pt-3Pd solder-substrate system were addressed. Calculations were based on the reaction couple formed between 63Sn-37Pb solder and 76Au-21Pt-3Pd substrates. Physical constants in the model were evaluated from experimental data. Consumption of the thick film was predicted as a function of time and compared with data from independent experiments. Sandia is a multiprogram laboratory operated by Sandia for the United States De- Corporation, a Lockheed Martin Company, partment of Energy under contract DE-AC04-94AL85000. 8:50 AM Invited Aging Study on the Solid-State Reactions between Long-Term 37Pb63Sn, 14Bi43Pb43Sn, 58Bi42Sn Solders and Ni Substrate 8:30 AM Invited Growth between Modeling 3-D Intermetallic Compound Layer Sn-Pb Solder and Porous Substrate Coatings Paul Thomas Vianco Albuquerque, NM 5800, MS1411, Box ries, Matls. Joining Dept., P.O. USA; 87185-1411 B. L. Shiau Sponsored by: Sponsored and Interconnection Electronic Packaging Division, Committee Materials Program Organizers: Packaging & Soldering Technologies & Soldering Packaging Kinetics Interconnects: for Electronic Joints in Solder Reaction of Interfacial Tuesday AM Murray Hill, NJ 07974 USA; Srini Chada, Motorola, Planta- Murray Hill, NJ 07974 Gautam Ghosh, Northwestern Univer- tion, FL 33322 USA; Evanston, IL 60208- Department of Materials Science, sity, AlliedSignal Electronic Materials, 3108 USA; Martin Weiser, USA Products, Spokane, WA Plated and Discrete March 14, 2000 Session Chairs: USA; K. N. Subramanian, Discrete Products, Spokane, WA Dept. of Mats. Sci. and Mech., Michigan State University, East Lansing, MI 48824-1226 USA

TUESDAY AM 79 samples areanalyzed byusingmetallographyand powderXRD.The prepared andannealed at160 investigated inthisstudy. In-Sn-Ni alloys ofvariouscompositionsare substrate andthephaseequilibria oftheIn-Sn-Niternarysystemsare In-Snalloysarepromisinglead-free solders.TheirreactionswithNi wan tional Tsing-Hua University, Dept. Chem.Eng.,Hsin-Chu30043Tai- ria ofIn-Sn-NiSystem Interfacial ReactionsinIn-Sn/NiCouplesandPhaseEquilib- 11:25 AM Invited the theoreticalcalculationiscomparedwithexperimentaldata. sumption oftheCu/Niduringsolderingreactionisproposed,and intermetallic aswellthegrowthrate.Akineticmodelofcon- diffusion behaviors,whichinturnaffectedthemorphologyof the interface revealedthatdifferentNi/Curatiosdemonstrated molten solderbath.EDXresultsoftheelementdistributionat the solder reactionwasstudiedwithalloyfoilsofvariousNi/Curatioand original intermetallicformationreaction.Inthisresearch,theUBM/ Cu/Sn system,however,bringsextracomplexitytothekineticsof the UBM duringthereflow. TheintroductionofNiintotheconventional correspondly reducestheconsumptionofwettingmetalsin pounds (IMC)growthrateatthesolder/UBMinterface.Thiseffect to beableeffectivelyreducethegrowthrateofintermetalliccom- Ni-containingunderbumpmetallizations(UBM’s) havebeenproved Dept. ofMatls.Sci.andEng.,356BardHall,Ithaca,NY14853USA Korhonen Containing UBM’sandEutecticPb/SnSolder A KineticStudyoftheIMCGrowthatInterfaceNi- 11:05 AM layer microstructure;3.growthrateevaluation. research include,1.samplepreparationmethod;2.solder/Cureaction metallic phaseformedandgrowthratedecreased.Thecontentsofthis similar wayincomparisontheinter-metallicgrowthrate.Ag positions, D1/2=f(Pbwt.%).TheinfluenceofAgareexamineda metallic growthrateconstantareexpressedasfunctionofalloycom- Pb-Sn binaryalloysandninePb-Sn-Agternaryalloys.Theinter- ing at4,9,16and25daysrespectively. Thesolderalloysincludesix inter-metallic phasesareexaminedunderSEMandEPMAafterhold- at 150 PurecoppersolderedwithPb-SnalloysandPb-Sn-Agstored Taiwan tional SunYat-sen University, Instit.ofMatls.Sci.andEng.,Kaohsiung, Influence ofAgContent The GrowthofCu-SnInter-MetallicsinSolderedCuandthe 10:45 AM scribes dissolutionreasonablywell. amount ofCudissolvedundernon-isothermalconditions,whichde- libria data.Anumericalmethodwasdevelopedforcalculatingthe microstructural changescanbeexplainedusingSn-Ag-Cuphaseequi- drites increasewithincreasingsolderingtemperatureandtime.The that thevolumefractionsofprimarySndencritesandetaphaseden- described byaNernst-Brunnerequation.Microstructurallyitwasfound dering temperatureandtimethattherateofdissolutioncouldbe amount ofCudissolvedduringsolderingincreasedwithincreasingsol- tent ofsamplessolderedundervariousconditionsshowedthatthe and x-raymicroanalysis.X-raymicroanalysisoftheaverageCucon- microstructure werestudiedbylightmicroscopy, scanningmicroscopy ThedissolutionofCuintomoltenSn-3.5Agsolderanditseffecton Rotunda Dr., Dearborn,MI48121USA 71083 Germany; tation, FL33322USA; Box 1881,Milwaukee,WI53201USA; Shangguan onMicrostructureEffect Copper SubstrateDissolutioninEutecticSn-AgSolderandIts 10:25 AMInvited 10:10 AMBreak microstructure. and jointintegritiesasafunctionofinitialsubstratemetallurgy ° C forlongperiodoftime.ThegrowthCu 1 4 ; MattA.Korhonen ; 1 Marquette University, Matls.Sci.andEng.Pgm.,P.O. 4 Ford MotorCompany, Visteon Auto.Sys.,17000 3 : Solectron GmbH,Solectronstr. 2,Herrenberg : : S.Chada Sinn-Wen Chen Ker-Chang Hsieh ° and240 1 ; Che-Yu Li 2 ; R. A.Fournelle ° 2 C. Thephasesformed inthe Srini Chada,Motorola,Plan- 1 ; Ching-Yu Huang 1 1 ; Hen-SoChang ; 1 : Cornell University, Peng Su 3 1 Sn andCu ; W. Laub 1 3 ; TiaM. Sn inter- 1 1 ; ; 3 1 1 6 ; D. Na- Na- Sn 5 nificant intheZn/NiandBi/Nisystemsat150 fects of300A/cm passage ofelectriccurrent,whichindicatethatelectromigrationef- of thetwosystems.Theresultsareidenticaltothosewithout to investigatetheelectromigrationeffectuponinterfacialreactions current of300A/cm addition tothesereactionexperimentsmentionedabove,anelectric sign ofexistenceintheBi/Nicouplesreactedupto144hours.In stable binaryNi-Biintermetallicatboth150 NiBi phase, wasformedintheBi/Nicouplesreactedat150 Zn/Ni couplesreactedatboth150 Eng., Hsin-Chu30043Taiwan stable binarycompoundsare kinetic ofthemetals andtheyieldsofelemental sulphur. Thispaper of chlorideinan acidsulphatebasedsystemto promotetheleach separation andrecovery, and,theuseofultrafine millingand/ortheuse advances andthewideracceptance ofsolventextractionformetals the directpressureleachingofnickel concentratesspurred,inpart,by ing. Thepastdecadehaswitnessed astrongresurgenceininterest specific applicationsbasedonsulphuric acidoxidativepressureleach- ammoniacal oxidativepressureleach basedprocess,andtotworather lurgical treatment hasbeenlimitedtotwoapplicationsofSherritt’s To date,however, thecommercialapplicationofdirecthydrometal- production ofelementalsulphur,ratherthansulphurdioxideoracid. impurity (arsenic,magnesium)feeds,highercobaltrecoveries,and based processes,includetheabilitytotreatlowergradeand/orhigher nickel sulphideconcentrates,overthetraditionalpyrometallurgically Potentialadvantagesusuallycitedforthedirectpressureleaching of 113 St.,FortSaskatchewan,AlbertaT8L4K7Canada M. Berezowsky Pressure LeachingofNickelSulphideConcentrates 8:30 AM Duisburg 47279Germany CO 80403USA;NorbertL.Piret,Piret&StolbergPartners, Session Chairs: March 14,2000 Tuesday AM & StolbergPartners,Duisburg47279Germany Associates, Houston,TX77242USA;NorbertL.Piret,Piret Program Organizers: Nickel, CobaltCommittee Sponsored by: Hydrometallurgy ofNickel Technology Applicationsinthe Cobalt andPreciousMetals:Pressure the Hydrometallurgy ofCopper, Nickel, Pressure Technology Applicationsin reached amaximumofabout6 η Chen Interfacial ReactionsinZn/NiandBi/NiCouples 11:45 AM couples reactedatboth160 cated, thereisonlyonecompoundformedinallthe(Sn-In)alloys/Ni the Sn-In-Nisystemsandphaseequilibriarelationshipsarecompli- are examined.Althoughtheremanyintermetalliccompoundsin wt.%Sn/Ni, andIn-80wt.%Sn/Nicouplesreactedat160 Ni phasesincreasedwithlongerreactiontime,whilethatofthe 2 In β 3 1 1 3 phasegrewwithtimeaswell.TheNiBiwhichisalsoa -NiZn, ; Sinn-Wen Chen , Ni 28 In η 72 -Ni , Ni 1 ; 15 Extraction &ProcessingDivision,Copper, 2 electricdensityuponinterfacialreactionsareinsig- Zn 1 3 Nic Hazen,HazenResearchInc.,Golden, Dynatec Corporation,Metallu.Tech. Div., 8301- Sn, Ni 2 densitywaspassedthroughthereactioncouples 21 1 and ; Location: OprylandConventionCenter Room: LincolnC 1 James E.Hoffmann,Hoffmannand National Tsing-Hua University, Dept.Chem. 3 Sn ° δ and240 -NiZn 2 andNi β -In ° µ and200 8 3 phases,formedattheinterfacesof m. Onlyoneintermetallic,NiBi Sn, ° 3 C upto144hours. Sn η , Ni 4 . In-49.1wt.%Sn/Ni,In-60 ° C. Thethicknessof ° 3 In, Ni and200 ° and200 2 ° In, Ni and200 ° : C showedno ° ° C. and240 Chih-Ming 3 : In ° 9 δ Roman , NiIn, C. The β phase 1 and ° C 3

TUESDAY AM 80 Eddie Hazen 1 Phelps 2 : ; 3 ; G. Houlachi 2 Bulong Nickel Operation, 1 ; 1 ; Jerry Hanks 1 ; G. J. McCunn 1 Noranda Technology Center, Pointe Claire, Pointe Center, Noranda Technology 3 ; Alan Williams 1 G. L. Frampton ; Phil Rooke : 1 ratios with associated high manganese content. It also results in sig- also results content. It manganese high with associated ratios rela- chrome, plus associated with platinum content metallic nificant to ore. The desire goethite within the content high scandium tively and manganese of high in the presence recovery cobalt maximise Whereas the recovery circuit. selection the metal chrome influence residues and from the leach recover refractory platinum potential to further circuit considerations. circuit water introduces scandium from 10:45 AM Madagascar Laterite Cobalt Recovery from Nickel and Chou St., Golden, CO 80403 USA; Research Inc., 4601 Indiana Dodge Exploration; Canada (PD) is currently developing a nickel/cobalt Phelps Dodge, Inc. provides technical assis- Hazen Research, Inc. deposit in Madagascar. recovery processes fro nickel and cobalt. tance to PD to investigate and were evaluated in laboratory experiments process options Various The process selected for the feasibility study pilot plant operations. high-pressure acid leach, countercurrent consists of feed preparation, precipitation, sulfide dissolution, solvent decantation wash, sulfide and electrowinning. Among these unit pro- extraction, ion exchange, leach, sulfide precipitation, and sulfide disso- cesses, high-pressure acid Process development lution are applications of pressure technologies. of these unit pro- work and design criteria for commercial operations related to scaling in the Concerns cesses are presented in this paper. processes are high-pressure acid leach and the sulfide precipitation under these envi- discussed. Corrosion rates of various metal coupons ronments were analyzed. AM 11:15 of the Commissioning Bulong Nickel Operations: A Review Pressure Acid Leach and Early Operations Phases in the High Plant 6430 Box 10391, Kalgoorlie, WA Svcs., P.O. Tech. metallurgical complex The Bulong Nickel Operation is a mining and Australia. in Western located approximately 30km east of Kalgoorlie solvent extraction and The process uses high-pressure acid leaching, cathode. The projected electrowinning to produce nickel and cobalt per year, with target ore-processing rate is up to 600,000 tonnes per year of nickel production levels of approximately 9000 tonnes in Phase 1. As expected metal and 640 tonnes per year of cobalt metal of mining, leaching and from a complex, integrated facility consisting early operating period refining operations, the commissioning and numerous challenges during the first ten months of 1999 has provided majority of these chal- to the process and engineering disciplines. The or are close to already, lenges have either been successfully addressed with the intention of being resolved. This paper has been written Acid Leach Plant reviewing the performance of the High Pressure during this period. Major issues influencing plant throughput rates, plant availabilities and plant recoveries have been highlighted and discussed. An attempt has been made to discuss these factors using a multidisciplinary approach that examines a number of significant chem- process and engineering aspects. istry, ; D. 1 Geoff : Outokumpu 1 ; 2 Brian C. Blakey University of Toronto, 3 : Outokumpu Research Oy, Outokumpu 2 University of Toronto, Dept. University of Toronto, 2 Inco-ITSL, 2060 Flavelle Blvd., 1 ; Stig-Erik Hultholm 1 ; 1 ; E. Krause 3 ; Kari Knuutila 1 Black Range Minerals NL, Syerston Nickel Cobalt Project, 1 ; ; M. Kawaji 1 Esa Lindell 2 : Level 10, 190 St. Georges Tce, Perth, Western Australia 6000 Perth, Western Tce, Level 10, 190 St. Georges is The Syerston Nickel Cobalt Project in Central New South Wales unique amongst the laterite projects being developed in Australia and laterite enrich- The unique nature ensues from the internationally. ment occurring over an Alaskan style ultramafic intrusion with dunite core. Characteristics that result include a goethite host mineralisation with low magnesium content and rapid extraction rates in High Pres- sure Acid Leach, along with low clay content and minimal viscosity problems. The base dunite mineralisation exhibits high cobalt to nickel F. James F. Mississauga, Ontario L5K1Z9 Canada; Canada; of Mech. and Indust. Eng., Toronto Canada Dept. of Chem. Eng. and Appl. Chem., Toronto, those containing signifi- Unlike most hydrometallurgical slurries, highly viscous and shear- cant concentrations of goethite are typically 5%. The viscosity may thinning, even at solid volume fractions below also depend upon time. These characteristics must be taken into consideration in slurry transport and heating. The technical literature is replete with apparent contradictions regarding the viscous behavior of these slurries, which may be due, in part, to variations in viscosity- present techniques which yield consistent measuring techniques. We results suitable for use in process design. A striking degree of time- meth- Reliable dependent behavior is demonstrated for a laterite slurry. ods to design and analyze tubular transport and heating systems for time-independent slurries are summarized. Rules of thumb are then of time-dependency. to account for the effects offered 10:00 AM Break 10:15 AM Application of Hpal at the Syerston Laterite Project Motteram Pori, Finland mattes at leach of the nickel deals with the pressure This paper The overall nickel process is also Metals Oy. Outokumpu Harjavalta in nickel plant was modernized and expanded shortly discussed. The t/ increase from 17 000 t/a to 40 000 1995 which led to a production expansion only cathode nickel was produced. a in 1999. Before the the is nickel powder and briquettes produced in The additional capacity a plant. Ammonium-sulphate is obtained as new hydrogen reduction an optional capacity to produce cobalt pow- by-product. There is also In the nickel smelter where the Outokumpu der via hydrogen reduction. two separate granulated products are produced: DON process is utilized (FSF) matte and electric furnace (EF) matte. flash smelting furnace refinery has two separate leach circuits one Consequently the nickel The FSF matte leach circuit consists of two for each type of matte. leach stages and two pressure leach stages counter current atmospheric matte leach circuit con- both in counter current arrangement. The EF stage. All reaction sists of an atmospheric and a pressure leaching Copper in the vessels and autoclaves are designed by Outokumpu. rich PGMs which is di- mattes is separated as a sulphide precipitate removed as a hematite rected to the copper smelter whereas iron is the first atmospheric residue from the EF pressure leach stage. From and copper free nickel leach stage of the FSF circuit neutral, iron solution is further sulphate solution is obtained. The nickel sulphate cobalt and other minor purified in a solvent extraction process where stream is then fed to the impurities are removed. The purified nickel plant. The pressure electrowinning and to the hydrogen reduction the start-up. Further- leach process has been in stable operation since production capacity more, the nickel process has reached its design according to the schedule. 9:30 AM of Goethite and The Viscous Behavior of Aqueous Slurries Design and Analysis Limonitic Laterite: Characterization for and Heating Systems Transport of Tubular provides, a discussion on leach chemistry, options on metals recovery on metals options chemistry, on leach a discussion provides, as operations, commercial of the existing a review solution, and from processes. promoted recently the most promising some of well as 9:00 AM Met- at Outokumpu Harjavalta Leach Process Nickel Pressure als Oy Harjavalta Finland; Metals Oy, Harjavalta

TUESDAY AM 81 P. A.Russo process cycletimes, anewheatingpracticefor34" diameterTi-6-4 Inresponseto aneedforincreasedfurnacecapacity andreduced 28110 USA eny Teledyne Co.,2020Ashcraft Ave., P.O. Box5030,Monroe,NC Forbes Jones Ingots Redesign ofFurnaceHeatingPractice for34"DiameterTi-6-4 9:20 AM perimentally observedbehavior. element analysissoftwarecode,showedgoodagreementwiththe ex- dation resultsofTIMETALâ-17 (Ti-17) usingDEFORM,afinite- mechanical propertydatabasegenerationarealsodiscussed.Forgevali- ate smallscaletestsforthepurposesofFEAmodelvalidationand evant totheconversionprocessbeingmodeledisdiscussed.Appropri- flow behaviorcorrespondingtospecificmicrostructuresthatarerel- ties andvalidationtrialsneedtobeconducted.Utilizationofmaterial turbine engines,appropriateexperimentstogeneratematerialproper- TIMETALâ-17 (Ti-5Al-2Sn-2Zr-4Cr-4Mo), aforging alloyforgas niques tomodeltheprimaryprocessingoftitaniumalloyssuch as Inordertodevelopaccuratefiniteelementanalysis(FEA)tech- USA Technical Laboratories,8000W. LakeMeadDr., Henderson,NV89015 sion ofTitanium Alloys Application ofFiniteElementAnalysistothePrimaryConver- 8:55 AM will yieldfinegrainalphathroughthesectionthickness. This informationhasbeenusedtopredictproductionprocessesthat thickness afterwaterquenchinghasbeenstudiedbythermalmodeling. of billetsectionsizeaswellforgingtemperatureonalphaplatelet by reducingalphaplateletthicknessduringbetaquenching.Theeffect lower thecriticalstrainrequiredforrecrystallizationofalphaplatelets demonstrated bythedeformationmodeling.Anotherapproachisto is toimpartmorestrainintocenter. Afeweffective wayshavebeen center ratherthanstrainhistory. To solve thisproblem,oneapproach above-mentioned problemisaresultofthethermalhistoryat the highesteffectivestrain.Basedonthisfact,itisspeculatedthat ever, 2.5Ddeformationmodelingclearlyshowsthecenteralreadyhas was hypothesizedtobetheresultoflowerstrainatcenter. How- lets inthecenteroflargesectionforgingscomparedtoedge.This equiaxed alphaforTi-6Al-4V. Itismoredifficult tobreakalphaplate- Forgingisusedtorefinecoarsecaststructure,anddevelopfine 1000 Warren Ave., Niles,OH44446USA; Modeling ofOpenDieForgingforTi-6Al-4V 8:30 AM Niles, OH44446-0269USA OR 97321USA;KuangOscarYu, RMICorporation,R&D, Session Chairs: March 14,2000 Tuesday AM Yu, RMICorporation,R&D,Niles,OH44446-0269USA USA; IsaacWeiss, JohnsonMattheyUSA;KuangOscar Idaho, IMAP-MinesBldg.#321,Moscow, ID83844-3026 Albany, OR97321USA;F. H.(Sam)Froes,Universityof Program Organizers: Shaping andFormingCommittee Division, StructuralMaterialsTitaniumCommittee, Sponsored by: Its Alloys:SessionI Production &ProcessingofTitanium Process SynthesisandModelingforthe : Ramesh S.Minisandram 1 ; J.M.Hjelm 1 ; RobertJ.McHugh Materials ProcessingandManufacturing James Hall,Oremet-Wah Chang,Albany, Location: OprylandConventionCenter Room: KnoxvilleB 1 ; G.W. Kuhlman : James A.Hall,Oremet-Wah Chang, Vasisht Venkatesh 1 ; JohnW. Pridgeon 1 ; RobertMarkDavis 2 ; 2 Consultant 1 RMI Titanium Company, 1 : ; S.P. Fox D. J.Li 1 ; 1 Allvac, Allegh- 1 1 ; K.O.Yu ; RobinM. 1 ; 1 TIMET 1 ; David U.Furrer Processing ofTitanium Cylindersby Roll FormingTechniques 10:50 AM phases. titioning betweenthehexagonalclosepackedandbodycenteredcubic and concludewithpresentationofdetailedanalysesthestrainpar- the influenceoftextureonformabilityasdeterminedbyr-values, bound andconstrainedhybridmodels).We willpresentresultsshowing tions thatlinkthemicroandmacroscales(again,upperbound,lower ume oftheaggregate,andprovideameanstoevaluatesimplerassump- anisotropy influencestheheterogeneityofdeformationovervol- These resultsquantifythedegreetowhichstrongsinglecrystal subjected toanidealizedrollinghistory(planestraincompression). in whicheverygrainisindividuallyresolvedwithfiniteelementsand discuss additionalmodelingresultsperformedonaggregatesofgrains ness variationsinthestrainingandfortextureevolution.We will ment formulationforflatrollingwhichaccountsthrough-thick- per bound,lowerandconstrainedhybrid)withinafiniteele- will compareresultsobtainedusingseveralmodelingassumptions(up- ing slipmodesassociatedwithc-axisextensionorcompression.We close packedphase,whicharisesfromtherelativedifficultyinactivat- nium ismadedifficultbythestrongyieldanisotropyofhexagonal a two-phasealloy(Ti-6Al-4V).Themodelingofplasticflowtita- evolution duringrolling,bothforcommercialpuritytitaniumand formability. Thispresentationwillfocusonthesimulationoftexture ropy isreadilyapparentinthestrengthofrolledproductsaswell enced bythecrystallographictextureimpartedprocessing.Anisot- Mechanicalpropertiesoftitaniumanditsalloysarestronglyinflu- Ithaca, NY14853USA Dawson Modeling Texture EvolutioninTitanium Rolling 10:25 AM verification anditsapplicationinaddressingmanufacturingproblems. model arepresentedalongwithafewexamplesthatillustrate used onaroutinebasisinaddressingproductionissues.Detailsofthe rapid turnaroundofsimulationresults,makingitahandytoolthatis model makesuseofauniquesteadystateapproachthatallowsfor cess asatransient(stroke-by-stroke)analysis.Allvac’s radialforging number ofstrokesinvolvedmakeitprohibitivetosimulatethepro- the type,canoperateatafewhundredstrokesperminute.Thelarge number ofrepetitivesteps.Radialforgingmachines,dependingupon Theradialforgingprocessisacomplexthatinvolves USA Minisandram Steady StateModelfortheRadialForgingProcess 10:00 AM 9:45 AMBreak cess willbediscussedalongwiththeexperimentaldetails. to 20%.Thepracticalhurdlesthatwereovercomeinthedesignpro- tice isexpectedtoreducefurnaceheatingtimeforingotproductbyup lb. ingotsinstrumentedwithsub-surfacethermocouples.Thenewprac- coupled withproduction-scaleexperimentaltrialsusingnominal17,000 on awidearrayofnumericalsimulationstheingotheatingpractice ingots isnowbeingimplemented.Thenewpracticewasdesignedbased range ofcylinder diameters,heightsandwallthicknesses. Acombina- processing consideration. Thisprocessiscapableof producingawide forming techniques,whilealloyed titaniummaterialsrequirespecial cesses. Commerciallypuretitanium canbereadilyprocessedbyroll the dimensionaltolerancecapability canapproachmachiningpro- components canbeproduced.Often conductedatroomtemperature, ing isaunique,incrementalextrusion processbywhichnetornear-net have beendevelopedandoptimized fortitaniummaterial.Rollform- tages, andassuch,methodstoproducethesetypesofcomponents Seamless processingofcylindricalstructureshaveshownmanyadvan- are oftenincylindricalgeometriesforcasings,tubesandotheruses. and non-aerospaceapplications.Componentsproducedfromtitanium Titaniumisanimportantmaterialutilizedinnumerousaerospace 8902, Cudahy, WI53110-8902 USA USA; Rsch. &Dev., 2020AshcraftAve., P.O. Box5030,Monroe,NC28110 2 Colorado StateUniversity, CivilEng.,FortCollins,CO80523 1 ; NathanBarton 1 ; RobinM.ForbesJones 1 ; RobertNiemi 1 ; 1 Cornell University, 196RhodesHall, 1 ; 1 Ladish CompanyInc.,P.O. Box 1 ; ErikG.Thompson : Paul Richard : 2 Ramesh S. ; 1 Allvac, :

TUESDAY AM 82 ; 1 Yip- : ; J. Allen Haynes 1 storage density provides 2 Stacie LeSure : Oak Ridge National Laboratory, Met. Oak Ridge National Laboratory, 1 ; 1 Northwestern University, Dept. of Matls. Sci. and Eng., Dept. of Matls. Sci. Northwestern University, 1 ; Bruce A. Pint 1 ; 1 Ian G. Wright Evanston, IL 60208 USA The magnetic spacing budget at 100 Gb/in an ultrathin overcoat only 2nm for the protective overcoat. Such smooth enough to allow must have the necessary wear resistance, be to provide corrosion low flying heights and be sufficiently defect-free One also requires layer. protection for the underlying magnetic media and materials in the overcoat to be compatible with the lubricant synthesize such a coating contact. It is desirable that the technique to In this paper, we be compatible with existing manufacturing practice. present preliminary results on the synthesis and characterization of three promising candidate coatings: (i) amorphous CNx; (ii) crystalline TiB2 and (iii) hydrogen-free amorphous carbon. Advantages and disadvantages of each coating material and the associated synthesis technique will be discussed. 9:35 AM Characterization of Oxide-Metal and Grain Boundary Inter- faces in Aluminide Bond Coats Box 2008, Oak Ridge, TN 37831- Surf. Sys. Grp., P.O. Div./Cer. & Cer. 6063 USA thermal barrier coat- efficiency, to increase gas turbine In an effort are used to protect superalloy components in gas ing systems (TBC’s) turbine engines. Most TBC systems consist of a superalloy substrate, an oxidation-resistant bond coat and a ceramic top coat. This study will focus on the formation and adhesion of a protective alumina scale at the bond coat- top coat interface. Adhesion of the scale, which is of factors, is influenced by a number the weak link in TBC durability, including bond coat platinum content. Thus, the purpose of this investigation is to examine the role of platinum in improving scale adher- will be Electron Microscopy (ATEM) ence. Analytical Transmission used to examine the alumina/bond coat interface in bond coats with and without platinum additions. Grain boundary segregation in the aluminide (Pt-Ni-Al) bondcoat on nickel based superalloy engine com- engine based superalloy on nickel bondcoat (Pt-Ni-Al) aluminide TGO excellent display bondcoats that Pt-Ni-Al It is known ponents. limited but chemistries, bondcoat to traditional adhesion relative scale scales for in the literature data exist chemical and microstructural to 2 microns the TGO is typically 1 TBC system. Since formed by this electron suited to transmission of the scale is well thick, analysis windowless TEM, scanning TEM, (TEM). Conventional microscopy loss spec- energy and electron X-ray spectroscopy, dispersive energy used to reveal the microstructural among the techniques troscopy were that the scale scale. It was found characteristics of the and chemical aluminum oxide (-Al2O3) in both as-deposited consists of hexagonal specimens; no metastable Al2O3 allotropes and in thermally cycled grains were as-deposited specimen, the scale’s were observed. In the observed to occur both Zr-rich particles were predominantly columnar. throughout the scale thickness, and their intra- and intergranularly upon approaching the YPSZ. Thermally cycled concentration increased of banded scale structure: one band specimens had a morphologically YPSZ had an equiaxed morphology and con- grains adjacent to the a second band of grains adjacent to the bondcoat tained Zr-rich particles; with axes oriented normal to the TGO/ had a columnar morphology is believed that this is the first experimental bondcoat interface. It banded scale containing Zr-rich dis- observation of a morphologically having a Pt-Ni-Al bondcoat. For specimens persoids in a TBC system equiaxed band and the undergoing up to 10 thermal cycles, both the thermal exposure. columnar band increased in thickness with increased by the equiaxed band However, the proportion of the scale comprised grains of the as- tended to decrease with greater cycling. The columnar in that the latter con- coated and thermally cycled specimens differed coarse in size. tained no Zr-rich particles and were comparatively irregular interface be- Porosity and cracks were associated with the at the YPSZ/TGO or tween the bands, but no porosity was observed can act as a weak link TGO/bondcoat interfaces. Since these defects that elimination of the promoting YPSZ spallation, it is expected It is proposed reliability. banded structure is key to improving TBC banded morphology is that formation of the equiaxed grains and the associated with the Zr-rich dispersoids. 9:10 AM Invited Overcoats Synthesis and Characterization of Ultrathin Chung Wah ; 1 Michael R. ; M. Radecka 1 : ; A. Kusior 1 A. Brudnik ; 1 Sudipta Seal, University of Central Sudipta Seal, University Polish Academy of Sciences, Instit. of Ca- 2 Room: Canal B Location: Opryland Convention Center Purdue University, Sch. of Matls. Eng., 1289 Purdue University, 1 ; 1 Sudipta Seal, University of Central Florida, Materials Processing and Manufacturing Materials Processing K. Zakrzewska : University of Mining and Metallurgy, Al. Mickiewicza 30, Al. Mickiewicza University of Mining and Metallurgy, 1 ; 2 ; J. L. Lee 1 MSEE Bldg., Rm. 150, West Lafayette, IN 47907-1289 USA MSEE Bldg., Rm. 150, West A chief influence governing the reliability of modern gas turbine is the adhesion of a thermally engine thermal barrier coatings (TBC’s) grown oxide (TGO) scale to both the bondcoat and the insulative ceramic topcoat layers. Factors affecting scale adhesion include TGO and bondcoat chemistry in addition to growth and thermal stresses developed during engine service. Several advanced TBCs incorporate an electron beam-physical vapor deposited (EB-PVD) yttria-partiallystabilized zirconia (YPSZ) ceramic topcoat and a platinum-nickel- talysis and Surf. Chem., Ul. Niezapominajek 1, Kraków 30-239 Poland talysis and Surf. Chem., Ul. Niezapominajek AFM (Atomic Force Mi- GID (Grazing Incidence Diffraction) and structure evolution in croscopy) were used to study the progressive by the reactive mag- thin films of TiO2-x. Thin films were deposited of Ti emission line netron sputtering with the controlled intensity parameter reflected a change in the in this (l=500 nm). Variation and as a consequence oxidation state of the sputtered metallic target titanium dioxide: ana- affected the growth of polymorphic forms of tase and rutile. The anatase was found to dominate the structure of films obtained from the oxidized target. The ratio of rutile/anatase phases was found to increase with the increasing intensity of Ti emission line, i.e. decreasing target coverage by oxides. AFM images gave evidence of two types of grains: those of smaller size constituting the base of the sample and large ones formed at the film surface. Good correlation was established between the relative distribution of these species and the structure evolution observed in X-ray diffraction experiments performed at different angles of grazing incidence. 8:50 AM Determination of the Structure and Chemistry of the Ther- mally Grown Oxide Scale in Thermal Barrier Coatings Con- taining a Platinum-Nickel-Aluminide Bondcoat Brickey Kraków 30-059 Poland; 8:30 AM Sputtered by Microstructure of TiO2-x Thin Films Reactively Dc Magnetron A. Kowal Tuesday AM Division, Surface Engineering Committee Division, Surface Engineering Program Organizers: Materials Processing and Analysis Florida, Advanced Materials and Aerospace Engineer- Center and Mechanical, USA; Narendra B. Dahotre, Univer- ing, Orlando, FL 32816 Institute, Center for Laser Applica- Space sity of Tennessee 37388 USA; Brajendra Mishra, tions, Tullahoma, TN Mines, Kroll Institute for Extractive Colorado School of 80401-1887 USA; John Moore, Colo- Metals, Golden, CO Department of Metallurgy and rado School of Mines, USA Materials Engineering, Golden, CO 80401 March 14, 2000 Session Chairs: Wah & MMAE, Orlando, FL 32816 USA; Yip AMPAC Dept. of Matls. Sci. and Chung, Northwestern University, Eng., Evanston, IL 60208 USA Sponsored by: Surface Engineering in Materials Engineering Surface I: Coating/Films Science (C)-I Characterization tion of manufacturing process design and material application can application and material design process manufacturing tion of components. titanium and economical in high performance result

TUESDAY AM 83 tained fromthestandard Sargentbathremainedunchanged onrecrys- after recrystallization. Thetexturesofchromium electrodeposits ob- changed tothe<100>,and textures,respectively, textures ofcopperelectrodeposits obtainedfromcoppersulfatebaths and maychangeafterrecrystallization. The<100>,<111>,and<110> Thetextureofelectrodeposits varieswithelectrolysisconditions Sci. andEng.,Shinrim-dongKwanak-gu, Seoul151-742Korea Joon HwanChoi of CopperandChromiumElectrodeposits Relation betweenDepositionandRecrystallization Textures 10:50 AM investigated. tion mechanismsinasinglesplatunderdifferentconditionsarealso condition ontheformationofcolumnarorequiaxedgrains.Solidifica- effect ofcoatingmaterial,substrateandthesurface heat transferanalysesareperformedusingthemodeltostudy the crystalline nucleiandthemeltundercoolingatnucleation.Detailed is incorporatedintheheattransfermodeltopredictformation of characteristics ofsplatsolidification.Theclassicalnucleationtheory surface. Aheattransfermodelisdevelopedtoanalyzethethermal large sizeswereseenintheMosplatssprayedonasmoothglass denum splatssprayedonasteelsubstrate,butgrainswithsignificant grains wereobserved.Finecolumnarformedinthemolyb- with veryhighgraindensity, althoughoccasionallysomeequiaxed most ofcases,theceramiccoatingsshowacolumnargrainstructure conia, andthesubstratematerialsaresteelglass.Itisfoundthat,in used includemolybdenum,alumina,andpartiallyyttria-stabilizedzir- splats plasma-sprayedondifferentsubstrates.Thecoatingmaterials some recentexperimentalobservationsofgrainstructuresinsingle terial, substratematerial,andprocesscondition.Thispaperpresents been foundinplasma-sprayedcoatings,dependingonthecoatingma- and microstructuresofeachsplat.Avarietygrainstructureshave the propertiesofacoatingthereforestronglydependonphases molten particlesimpactatahighspeedonsubstrate.Thequalityand Plasma-sprayedcoatingsaremadeofsmallsplatsformedwhen Stony Brook,NY11794-2275USA York, Dept.ofMatls.Sci.&Eng.,Ctr. fortheThermalSprayRsch., Ctr. 106B,Akron,OH44325-3903USA; 1 Experiment andModeling Grain StructureDevelopmentinPlasmaSprayedCoatings: 10:30 AM 10:15 AMBreak particles sprayingprocess. step furthertowardtheunderstandingandoptimizingofTiSi2 melted. Thephenomenawerediscussed.Thisinvestigationprovideda in bothcases.ItimpliedthatmostoftheTiSi2particleswereverywell revealed thatthefeaturesofcoatingswerecharacterizedbysplashing tute incoatingobtainedlowpressurechamber. SEMobservation of TiSi2werealsofound.Incontrast,phasewasamajorconsti- Ti5Si3, whichwaspredominantincoating.Inaddition,oxideproducts in aircondition,somestartingTiSi2particlesweredecomposedinto probe microanalysis(EPMA).TheXRDpatternsshowedthat,sprayed croscopy (SEM).Chemicalcompositionswereexaminedbyelectron tion (XRD).Microstructureswereobservedbyscanningelectronmi- device. ThephasespresentincoatingswereanalyzedbyX-raydiffrac- experiments werecarriedoutwithaconventionalDCarcplasmaspray sprayed, inbothairandlowpressureconditions,respectively. All of coatingswasreportedinthisarticle.TiSi2particles(<44Êm)were Effectofplasmasprayprocessingparameteronthemicrostructure Mitaka, Tokyo 181-0004Japan 1 in BothAirandLowPressureConditions Microstructures ofTiSi2CoatingsObtainedbyPlasmaSpray 9:55 AM hot-stage AugerElectronSpectroscopy(AES). phenomena occurringatthebondcoatsurfacewillbestudiedusing microstructures ofthebondcoatsandscales.Additionally, segregation ning electronmicroscopy(FEG-SEM)willbeusedtocharacterizethe bond coatwillalsobeinvestigatedbyATEM. Fieldemissiongunscan- The UniversityofAkron,Dept.Mech.Eng.,AuburnSci.&Eng. Ship ResearchInstitute,Matls.andProcess.Div., Shinkawa6-38-1, 1 ; SooYoung Kang : Guo-Xiang Wang 1 ; 1 Seoul NationalUniversity, Matls. 2 State UniversityofNew : : G. Li 1 ; SanjaySampath Dong NyungLee 1 ; S.Uematsu 1 1 2 ; ; ; coating. strate andimprovingthenucleationrateadhesionofdiamond preventing therapiddiffusionofhydrogenandcarbonintosub- plasma nitridingfollowedbycarbonitridingwaseffectivein diamond crystalsandpooradhesion.Agradedinterlayercombining substrate, butresultsshowedarelativelylownucleationdensityof could preventtherapiddiffusionofhydrogenandcarbonintotitanium diamond coatinghadpooradhesionstrength.Plasmanitridedlayer as theprecursorfordiamondnucleation.However,so-formed diamond crystalswereformedonDLCinterlayerinwhichacted gen plasmaandchangedtodiamondcrystals,atthesametime,new diamond-like-carbon (DLC)interlayer. DLCfilmwasetchedbyhydro- adherence. Thereweretwomechanismsfordiamondnucleationon ation andgrowth,thedepositeddiamondcoatingsshowedapoor interlayer, therewasnosignificantimprovementindiamondnucle- the nucleidensityofdiamondcrystals.ResultsshowedthatonTiN strate usinghydrogenplasmaforashorttimesignificantlyincreased diffusion ofhydrogenintothesubstrate.Pre-etchingtitaniumsub- crystals increasedsignificantly. However, itcouldnotpreventthe pre-treatment indiamondsuspensions,thenucleidensityof showed thatafterpolishingwithdiamondpastesandultrasonically surface treatmentsandinterlayerswerestudiedinthispaper. Results rapid diffusionofhydrogenandcarbonintothesubstrate,different coating). To increasethediamondnucleationrateandprevent crystals (thusdecreasingthenucleationandgrowthrateofdiamond into substrate,theformationofcarbideandnucleationdiamond substrate. (2)Competitionamongtherapiddiffusionofcarbonatoms formation ofhydridethusdegradingthemechanicalproperties processes: (1)Diffusionofhydrogenintotitaniumsubstrateandthe Duringdiamonddepositionontitaniumsubstrate,thereexisttwo Schl. ofAppl.Sci.,639798Singapore Prod. Eng.,639798Singapore; 1 Yongqing Fu and GrowthofDiamondCoatingsonTitaniumSubstrate ofPre-TreatmentsEffects andInterlayersontheNucleation 11:10 AM tion duetodislocationsinthenon-recrystallizedgrains. direction canbeparalleltotheabsolutemaximuminternalstressdirec- lized grainsorientthemselvessothattheirminimumelasticmodulus strain energyreleasemaximizationmodel.Inthemodelrecrystal- tallization. Theresultsareinagreementwiththepredictionof Nanyang Technological University, Matls.Lab.,Schl.ofMech.& 1 ; NeeLamLoh 1 ; BiboYan 2 Nanyang Technological University, 1 ; ChangQ.Sun 2 ; PeterHing 2 : ;

TUESDAY AM 84 ; ; 1 1 Rainer : ; K. Hono 1 Samuel Benavides : M. Murayama phase is observed along the phase is observed along θ : m as a result of grain growth. At µ The University of Texas at El Paso, The University of Texas 1 ; 1 ’ two-phase Al-1.7at.%Cu alloy has been ’ two-phase Al-1.7at.%Cu θ + α ’ precipitates are dissolved and a fine grained ’ precipitates are dissolved C. The ability to weld any metals or alloys at - C. The ability to weld any metals or alloys at θ University of Wisconsin-Madison, 1500 Engi- ° 1 ’ precipitates are severely deformed after the first ’ precipitates are severely ; 1 θ National Research Institute for Metals, Tsukuba 305- for Metals, Tsukuba National Research Institute m. At higher welding temperatures the residual grain size m. At higher welding temperatures the residual 1 Kyushu University, Dept. of Matls. Sci. and Eng., Fukuoka Dept. of Kyushu University, 2 µ C to -100 ° ; 2 ; Lawrence E. Murr 1 C the welding produced a very narrow temperature spike of around C the welding produced a very narrow temperature C is in itself rather extraordinary, especially since the steady- C is in itself rather extraordinary, C, precipitation of the equilibrium C, precipitation of the C, but the residual grain sizes remained in the sub-micron range. In C, but the residual grain sizes remained in the ° ° ° ° m and 0.8 precipitates. The supersaturation required for precipitation of the precipitates. The supersaturation required 100 somewhere between 0.5 state (recrystallized) grain size appears to be µ in the weld zone increases to near 10 -100 240 with the workpiece sub- this case the welding was actually performed been examined in de- merged in liquid nitrogen. Microstructures have The weld zone properties tail using transmission electron microscopy. were monitored by measuring and comparing residual microhardness profiles through the stir-welded zone and extending into the base metal (workpieces). Research supported in part by a NASA Cooperative and Mrs. MacIntosh Murchison En- Agreement NCC8-137 and a Mr. dowment. 10:00 AM Amorphization of Al-Sm-Based Alloys by Cold-Rolling 1217 ERB, Madison, WI 53706 USA neering Dr. Melt-spinning and splat-quenching as traditional production techniques for amorphous materials often result in the formation of quenched in nuclei and subsequent nanocrystal formation during processing. Intense straining and cold-rolling offer not only the opportunity for the formation of bulk amorphous material but also for a new approach to study the nanostructural evolution during processing. Cold- rolling of Al92Sm8 yielded a partially amorphous sample that revealed a clear glass transition during linear heating in DSC. Modulated DSC reflected a similar Tg for melt-quenched Al92Sm8 thus indicating that amorphous Al92Sm8 is a true glass in contrast to amorphous, short- range ordered structures. A systematic study of Al-Sm based alloys following cold-rolling has been conducted in terms of the dependence of the glass-transition behavior as well as the grain size and micro- occurs after high strains and the microhardness decreases. This process This decreases. the microhardness strains and after high occurs and the crystallite growth grain by significant accompanied was not the As a result, deformation. plastic stable during essentially size was place. took structure submicrocrystalline equilibrium of an formation submicro- of the non-equilibrium of transformation A mechanism one will be considered. into a recrystallized crystalline structure 9:20 AM Deformed Al-1.7at.%Cu Alloy Evolution in an Microstructural Angular Pressing by Equal-Channel Z. Horita 0047 Japan; 812-8581 Japan during the equal channel angular (ECA) The microstructural evolution pressing process of an electron microscopy (TEM) and energy-fil- studied by transmission tered TEM. The with a strain of e~1. After 8 passes of ECA pass of ECA pressing that pressing, most of the only GP zones are formed in the undeformed grain boundaries, whereas in the ultrafine specimen. This suggests that the grain boundaries nucleation sites for the grained microstructure provide heterogeneous θ the grain boundaries. GP zones is lost quickly by diffusion of Cu to 9:40 AM of Alu- in the Friction-Stir Welding Ultrafine Grain Structure minum Alloy 2024 at Low Temperatures Li Ying El Paso, TX 79968- University Ave., Metallu. and Matls. Eng., 500 W. 0520 USA intercalation process Friction-stir welding involves a solid-state accommodates super- facilitated by dynamic recrystallization which Adiabatic and frictional heating, a result of high strain and plastic flow. process. In high strain-rate deformation, drive the recrystallization for aluminum alloy this study we examined the residual grain structures which ranged from 2024 friction-stir welded at starting temperatures roughly 30 Johannes Hebert (~500nm) supersaturated solid solution is obtained. When the ultrafine (~500nm) supersaturated at prepared by ECA pressing is aged for 24 h grain single phase alloy 100 ; 2 D. R. ; 2 University of 1 ; m. An attractive 1 m. A highly non- µ µ ; D. Gromov 2 : Minoru Furukawa Kyushu University, Dept. Kyushu University, m could not be produced 3 µ ; F. Musin ; F. 2 Institute for Metals Superplasticity 2 Terence G. Langdon Terence ; 3 Rajiv S. Mishra, University of Rajiv S. Mishra, Fukuoka University of Education, Dept. of Room: Polk A/B Convention Center Location: Opryland 2 Naresh N. Thadhani, Georgia Institute of Naresh N. Thadhani, Georgia Institute : R. Kaibyshev Materials Processing and Manufacturing Materials ; Minoru Nemoto 3 Lawrence Livermore National Laboratory, L-342 P.O. Box L-342 P.O. Lawrence Livermore National Laboratory, 1 ; 1 which were free of internal stresses. In addition, this structure is non- uniform. Secondary recrystallization was observed to occur with the formation of grains which were greater than 10 alternative for the conversation of a non-equilibrium ultrafine grain structure into an equilibrium one is via plastic deformation. The microstructural evolution during plastic deformation of the 6061 aluminum alloy with an initial submicron structure will be discussed in detail. It was shown by X-ray analysis, TEM examinations and microhardness tests that plastic deformation led to a decrease of internal elastic stresses due to recovery of grain boundary dislocations. Adsorption of grain boundary defects and the formation of a recrystallized structure equilibrium structure was produced with a high density of extrinsic dislocations at grain boundaries which are sources of long-range stress fields. As a result, the alloy demonstrates poor workability and insuf- processing approaches for reducing the ficient service properties. Two internal stress were evaluated. The first approach involved recrystallization annealing which was effective in relaxing internal stresses. However, the relaxation of internal stresses was accompanied by dramatic grain coarsening. Using a recrystallization anneal, microstructures with average grain size less than 1.5 Lesuer 808, Livermore, CA 94551 USA; Problems RAS, Khalturina 39, Ufa 450001 Russia Ultrafine grain structures have been produced in a 6061 aluminum alloy using ECAE. The average size was 0.4-0.5 Tech., Munakata, Fukuoka 811-4192 Japan; Munakata, Fukuoka 811-4192 Tech., Southern California, Depts. of Matls. Sci. & Mech. Eng., Los Angeles, Southern California, Depts. of Matls. Sci. & Mech. CA 90089-1453 USA; 812-8581 Japan of Matls. Sci. & Eng., Faculty of Eng., Fukuoka processing method which Equal-Channel Angular (ECA) pressing is a metals Typically, may be used to achieve substantial grain refinement. the submicrometer range. subjected to ECA pressing have grain sizes in the development of a This paper considers the factors influencing separated by high angle homogeneous microstructure of equiaxed grains the strain introduced on grain boundaries, including the pressing speed, of specimen rotation each passage through the die and the effect between consecutive pressings. 8:55 AM Invited Structure in a 6061 Formation of Equilibrium Ultrafine Grain Aluminum Alloy 8:30 AM Invited Ultrafine Grained Ma- Factors Influencing the Development of terials through Severe Plastic Deformation Sponsored by: Sponsored and Committee, Shaping Powder Metallurgy Division, Forming Committee Program Organizers: Ultrafine Grained Materials: Severe Materials: Grained Ultrafine I Processing: Deformation Plastic Tuesday AM Missouri, Metallurgical Engineering, Rolla, MO 65409-0340 Missouri, Metallurgical Materials Director- Laboratory, Wright USA; S. L. Semiatin, USA; C. Suryanarayana, Colorado ate, Dayton, OH 45440 of Metal and Materials School of Mines, Department CO 80401 USA; Naresh Thadhani, Engineering, Golden, School of Materials Institute of Technology, Georgia Atlanta, GA 30332-0245 USA Science and Engineering, March 14, 2000 Session Chair: Atlanta, GA 30332-0245 USA Technology, Zenji Horita

TUESDAY AM 85 low andhighangle dislocationboundariessurrounding nanometerto Grainsubdivision duringdeformationresultsina distributionofboth P.O.Box 49,RoskildeDK-4000Denmark 94551-0969 USA; for Matls.andEng.Sci.,P.O. Box 969, M.S.9403,Livermore,CA Darcy A.Hughes formed MetalsOvertheEntire MisorientationAngleRange Characterization ofSub-Micrometer StructuresinHeavilyDe- 11:20 AM tion ofprocessingconditionswillbediscussed. ing repetitiveECApressingofpurealuminum.Implicationstoselec- tion ofthegrain-to-grainmisorientationaswellmicrotexturedur- ter. Thesemethodshavebeenemployedheretoexaminetheevolu- ods enablestheevaluationofmicrotextureandgrainboundarycharac- computer-aided electronbackscatterdiffraction(EBSD)analysismeth- ment ofgrain-to-grainmisorientationbyuserecentlydeveloped cantly dependentonthedetailsofprocessroute.Directmeasure- and recrystallizationduringrepetitivepressingoperationsaresignifi- evolution ofthedeformationmicrostructureandrolesrecovery loys. Frominvestigationsbytransmissionelectronmicroscopy the submicron grainsizeshavebeenattainedinaluminum-magnesium al- ported forpurealuminumprocessedbyrepetitiveECApressingand aluminum anditsalloys.Grainsizesofabout1.0 ing isapromisingapproachtoachievingextremegrainrefinementin Severeplasticdeformationbyequal-channelangular(ECA)press- Eng., LosAngles,CA90081-1453USA 3 University, Dept.ofMatls.Sci.andEng.,Fukuoka 812-8581Japan; Mech. Eng.,700DyerRd.,Monterey, CA93943-5146 USA; Horita of Pure Aluminum texture andGrainBoundaryCharacterduringECAPressing The InfluenceofProcessingRouteontheEvolutionMicro- 10:55 AMInvited on thisinvestigation. ing temperatureandtime.Thistalkwillsummarizeourresultstodate soids inthestructuralstabilityhasbeenstudiedasafunctionofanneal- been analyzedbyoptical,andelectronmicroscopy. Theroleofdisper- Initial studiesonseveralAlalloyscontainingdispersoidparticleshave sheets ofaluminumalloystocreatedesiredfine-scalemicrostructures. deformation techniquehasbeendevelopedandappliedtoplates structure-altering aspectsofrollingdeformation,asurface-shearbased make scale-upofbilletsizeanontrivialproblem.To minimizethese process scale-upisdie-wallstickingwiththemovingworkpiece,which and thishasbeenfoundtoaltertheirmicrostructure.Anotherissuefor is asheet,furtherrollingrequiredaftertheseveredeformationsteps, which needstobeaddressedinthefutureyears.Ifdesiredproduct deformation andtothermalexposureishoweveramajorproblem nm sizemicrostructures.Stabilityofthesemicrostructurestofurther etc. arefoundmoreconvenienttocreatebulkmaterialswith50ñ500 forging, ECAE(EqualChannelAngularExtrusion),pressurizedtorsion structured samples,butrepeateddeformationmethods,suchas3-axis deposition processeshavebeenusedforproducingsmallscalenano- to obtainimprovedstrengthandprocessabilityinthesealloys.Vapor creating nanocrystallinemicrostructuresinmetallicalloysaneffort Significantinterestexistsinthematerialssciencecommunity USA sity ofMichigan,Dept.Matls.Sci.andEng.,AnnArbor,MI48109 Ultrafine Microstructures Severe DeformationBasedProcessforGrainSubdivisionand 10:30 AMInvited 10:20 AMBreak acknowledged. tures. ThesupportoftheARO(DAAG55-97-1-0261)isgratefully the potentialforsynthesisofbulknanocrystaloramorphousstruc- that intensecold-rollingcanyieldglass/nanocrystal-structuresandhas rolling responseofAl-Smalloys.Thisexperiencehasdemonstrated accounted forbytheinfluenceofselectedNi-additionsoncold- tion. Theeffectofmulticomponent-alloyingontheamorphizationis structure onboththenumberofrollingcyclesandsoluteconcentra- University ofSouthernCalifornia,Dept.Matls.Sci.andMech. 2 ; Terry G.Langdon 1 ; NielsHansen : 2 Risø NationalLaboratory, Matls.Rsch.Dept., Terry R.McNelley : 3 ; A. K.Ghosh 1 Naval PostgraduateSchool,Dept.of 2 ; 1 Sandia NationalLaboratories,Ctr. 1 ; DouglasL.Swisher 1 ; W. Huang µ m havebeenre- 1 ; 1 The Univer- 2 Kyushu 1 ; Zenji : elevated temperature. temperature, someofthemshowedlowtemperaturesuperplasticityat rials showedlimitedductility(especiallyuniformelongation)atroom steel iftheyhadultra-finegrains.Thoughthegrainedmate- ingly discontinuousyieldingappearedeveninpurealuminumandIF than thatofthestartingmaterialsatambienttemperature.Interest- grained materialsshowedverylargestrengthtwotofourtimeslarger the microstructureofmaterialwasalsoclarified.Theultra-fine discussed. Effectoflubricationinroll-bondingonthepropertiesand ture annealing.Theformationprocessoftheultra-finegrainswillbe structure, however,ultra-finegrainsformedinthembylowtempera- perature didnotshowultra-finegrainsbutcomplicateddeformation restoration duringreheating.ThematerialsARBedatambienttem- to accumulatestrainobtainultra-finegrainsbecauseofenhanced nano-meters. Aboverecrystallizationtemperature,itwasimpossible were filledwithultra-finegrainswhosediameterwasseveralhundred temperatures belowrecrystallizationtemperature,theARBedsheets peratures, theARBwassuccessfullycarriedout.Especiallyatwarm temperatures intherangefromroomtemperaturetohot-rollingtem- aluminum alloys,interstitialfreesteelandlow-carbonsteel.Atvarious also abondingprocess(roll-bonding).TheARBwasappliedtovarious material, therollinginARBisnotonlyadeformationprocessbut to betheinitialthickness,androlledagain.Inorderobtainsolid lative Roll-Bonding(ARB).InARB,therolledmaterialwascut,stacked straining processapplicabletolargestructuralmaterials,theAccumu- been significantlystudied.We haverecentlydevelopedanovelintense Ultra-grainrefiningofmetallicmaterialsbyintensestraininghas Sci. &Eng.,2-1Yamadaoka, Suita,Osaka565-0871Japan by AccumulativeRoll-Bonding Ultra-Fine GrainedFerrousandAluminumAlloysProduced 11:40 AM under contractNo.DE-AC04-94AL85000. work wassupportedbytheOfficeofBasicEnergySciences,U.S.DOE angle boundariesconstituteakindofgrainrefinement.Partthis The questionisconsideredofwhetherthesedeformationinducedhigh as cyclic-extrusion-compressionandequal-channel-angle-extrusion. deformation byrollingorsimpleshearandmorecomplexpathssuch the boundarymorphology. Acomparisonismadebetweenmonotonic type canmodifytheboundaryspacingandangledistributionsaswell increasing deformation.Differentdeformationmodesandmaterial structure andthatthefractionofhighangleboundariesincreaseswith deformation. Itisobservedthattheseboundariesrefinethemicro- tron microscopyandTEMKikuchidiffractionasafunctionofthe distributions, arequantifiedusinghighresolutiontransmissionelec- including morphology, aswellspacingandmisorientationangle micrometer scaledvolumes.Keycharacteristicsoftheseboundaries, 0871 Japan; sity, Dept.ofMatls.Sci.&Eng.,2-1Yamadaoka, Suita,Osaka565- Yoshinori Ito 2 2 Graduate StudentofOsakaUniversity, Dept.ofMatls. ; HiroshiUtsunomiya : Nobuhiro Tsuji 1 ; Tetsuo Sakai 1 1 ; Yoshihiro Saito ; 1 Osaka Univer- 1 ;

TUESDAY AM 86 ; 1 A. : ; J. B. 1 ; Minoru 1 ; Tadahiko 1 ; Kazumasa ; Yukihiro 1 1 L. J. Little ; F. D. Schowengerdt ; F. 1 : ; Hirokatsu Aoki ; Yoshito Arai ; Yoshito 1 1 ; Sinnichi Yoda 1 ; J. J. Moore 2 ; Naokiyo Kosikawa 1 ; Akira Tanji 1 ; Akitoshi Mizuno 1 ; Natsumi Tateiwa 1 ; J. Y. Guigne ; J. Y. 2 Guigne International Limited, Paradise, Newfound- 2 National Space Development Agency of Japan, Tsukuba National Space Development Agency of Japan, ; H. C. Yi Toshio Itami Toshio 1 1 University of Alabama, Dept. of Matls. and Mech. Eng., University of Alabama, Dept. of Matls. and 1 : ; 1 ; 1 ; Tomihisa Nakamura ; Tomihisa ; Tomoharu Fukazawa ; Tomoharu 1 1 ; Yukiko Yamaura ; Yukiko 1 Colorado School of Mines, Dept. of Metallu. and Matls. Eng., Golden, R. Manerbino Birmingham, AL 35294 USA alloys leads to sedi- Ground-based processing of binary immiscible microstructures, early mentation. In an attempt to obtain dispersed alloys were pro- experiments were performed in which immiscible However upon evaluation of the samples from cessed in microgravity. separated structure was these experiments, it was discovered that a One pos- obtained, where one phase completely surround the other. sible cause for this segregation in microgravity-processed immiscible alloys was believed to be perfect wetting. The purpose of this research is to investigate the wetting behavior in immiscible alloys and determine the mechanisms behind the segregation process. A transparent cell assembly will be used in order to permit direct observation of the solidification process. The succinonitrile-glycerol system and the succinonitrile-water system will be utilized in the investigation to evaluate the wetting phenomenon. It is anticipated that this research will give insight into perfect wetting behavior and information concerning its influence on the microstructures obtained from microgravity processing. 3:20 PM Break 3:40 PM Combustion Synthesis of Porous Glass Ceramic Materials 1 CO 80401 USA; land A1L 1C1 Canada Combustion synthesis also know as, Self-Propagating High Tem- perature Synthesis (SHS), is a processing method which utilizes exothermic reactions to produce advanced materials which could prove to have many applications. This technique is used to produce glasses in In most of crystal growth experiments of semiconductor under of semiconductor of crystal growth experiments In most methods by static research materials were analyzed the microgravity, situ observa- of the mission. An in after the completion on the ground microgravity methodology during as a promising tion is considered experimental used of the limited in order to make full experiment of resources, because simultaneous observation opportunities and their and the environment can more precisely reveal the growing interface temperature and concentration gra- the influence of supersaturation, An in surface kinetics on the growth behavior. dients, convection, and for solution growth process of semiconductor situ observation setup on static magnetic field experiment based was developed for a high the axial magnetic field ex- Subsequently near-infrared microscopy. of 6 were performed to reveal the influence periments from 0 to the flow on the growth surface. As a result, strongly-damped fluid rates were successfully obtained using the setup dissolution and growth instability of the surface will The morphological with a high accuracy. be discussed in detail. 2:40 PM Reactive Liq- Diffusion Experiment for Very The Microgravity uid Metals Kaneko Goto Masaki Ibaragi, Japan 2-1-1 Sengen, Tsukuba, Space Ctr., features from the The space experiment still has many different is only one chance with- laboratory experiments, for example, there the proceed of safety, out the repetition, strictly a requirement for it is not always easy long time since sample is delivered, etc. Therefore very reactive materials. to perform the microgravity experiments for method for In this report description is given for the experimental and its applica- diffusion experiments of liquid Li under microgravity tion to rocket experiment due to the TR-IA-6-rocket. 3:00 PM Phenomena in Immiscible Alloys Wetting Andrews Nakamura ; 2 A- ; S. 1 12.6 Ni 15.4 TUESDAY PM TUESDAY Cu 5 ; U. Geyer ; Takao Maki ; Takao 1 1 T values are as Nb ∆ 57 ; J. Schroers 1 California Institute of Technol- 1 ; Kengo Horiuchi ; 1 1 C. C. Hays : The Institute of Space and Astronautical 1 Robert Schiffman, R.S. Research Inc., Robert Schiffman, R.S. Location: Opryland Convention Center ; 1 ; Ayako Kato ; Ayako 1 ; W. L. Johnson ; W. 1 C. Patuelli, Universita di Bologna, Dept. di C. Patuelli, Universita di Bologna, Dept. ASM International: Materials Science ASM International: T 100K. Differential thermal analysis (DTA) measurements thermal analysis (DTA) T 100K. Differential ∆ ; N. Stein Yuko Inatomi Yuko 1 T=(Tx-Tg), as determined from calorimetric measurements is T=(Tx-Tg), as determined from calorimetric ∆ : T 70K. This alloy has been investigated by our group in recent T 70K. This alloy has been investigated by 0 (Vit 106), developed at Caltech exhibits an exceptional glass form- 0 (Vit Olympus Optical Company Limited, 2951 Ishikawa-chou, Hachiouji, 1 Tokyo 192 Japan Tokyo 2 Science, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510 Japan; Science, 3-1-1 Yoshinodai, l Kazuhiko Kuribayashi Bossuyt as large show that the onset of melting for this new alloys is 10 K less than that by 106. When examined in the ESL the new alloys are vitrified of Vit purely radiative cooling. This is the first non-Be containing alloy to be vitrified on free cooling in the ESL. This places the microstructural properties of the ESL processed materials were examined by x-ray and thermal analysis electron- and optical-microscopy, diffraction, methods. These results are used to interpret the complex evolution of the glass forming properties observed in this alloy system. 2:20 PM Solution Growth of Semiconductor in an Axial Static Magnetic Field ing ability (GFA) and has an excellent thermal stability with respect to ing ability (GFA) supercooled liquid recrystallization. For example, the width of the gion ∆ conducted at the NASA electrostatic levitation (ESL) experiments Inde- Levitation facility. Marshall Space Flight Center Electrostatic 106 specimens show conclusively pendent ESL experiments on Vit (TTT) diagram for this that the Time-Temperature-Transformation branches. The alloy is a superposition of high and low temperature 1-2 seconds, which pre- nose of the TTT diagram is located at tnose 106 specimens on free cooling in the ESL. As vents vitrification of Vit part of our continuing investigations of alloys in the Zr-Nb-Cu-Ni-Al system, we have identified a neighboring composition, Zr58.5Nb2.8- com- Cu15.6Ni12.8Al1 0.3, that exhibits a substantially improved GFA 106. This alloys is easily vitrified by standard techniques; pared to Vit e.g., arc melting and melting on a water cooled silver boat apparatus. Using these methods, the critical casting thickness for this composition is near 1cm. The calorimetrically determined Session Chair: Materia, Bologna Fisica ed Istituto Nazionale di Fisica della I-40127 Italy 2:00 PM Bulk Me- Electrostatic Levitation Processing of Zr-Nb-Ni-Cu-Al tallic Glass Forming Alloys USA Dept. of Matls. Sci., 138-78, Pasadena, CA 91125 ogy, alloy system The bulk glass forming ability in the Zr-Nb-Cu-Ni-Al Zr is well established. One of these bulk metallic glasses, Tuesday PMMarch 14, 2000 Room: Memphis A Barton, VT 05822 USA; Carlo Patuelli, Universita di Bolo- Barton, VT 05822 USA; Fisica, Bologna I-40126 Italy gna, Departimento di Critical Technology Sector, Electronic, Magnetic & Photonic Electronic, Magnetic Sector, Critical Technology Structural Materials Division, Alloy Materials Division, Thermodynamics & Phase Equilibria Phases Committee, Committee Program Organizers: Sponsored by: 12th International Symposium on Symposium 12th International for Microgravity Methods Experimental Session 2 Materials Science:

TUESDAY PM 87 ture (T dispersion uniformity. Experimentalresultstoevaluate microstruc- ated withthistechniquehavebeen evaluatedinviewofoptimizing tion withappliedultrasonicenergy. The processingparametersassoci- analogue, succinonitrile-glycerol system wereconductedinconjunc- cence phenomena.Experiments with thetransparentorganic,metal segregation stilloccursduetogravity independentwettingandcoales- between thephases.Microgravityprocessingminimizessettling but miscible liquidsonEarthishamperedbyinherentdensitydifferences Uniformmicrostructuraldevelopmentduringsolidificationofim- Ctr., MS-MSD47,Huntsville,AL35812USA Korea; Grugel ence ofAppliedUltrasonicEnergy Solidification ProcessingofImmiscibleLiquidsinthePres- 4:40 PM refinement inundercooledpurecobalt. cooling wasincreasedfrom20to320K,demonstratingthegrain average grainsizewasdecreasedfrom500to30mmwhentheunder- of classicalnucleationtheorycoupledwithstatisticalapproach.The long droptube.Undercoolingdataareanalyzedwithintheframework been achievedinthelowgravity, containerless environmentofthe clustered from300to330K.Comparablylargeundercoolingshave corded forthesame4-millimetersample,90%undercoolingvaluesare 99.5 and99.999%.Amongthetotalof1,155nucleationeventsre- sample diameterinthe1to10mmrangeandmaterialpuritybetween average andmaximumundercoolingwasobservedtobeinsensitive flux agentonundercoolingwereinvestigated.Forfluxingexperiments, drop tube.Theeffects ofsamplesize,materialpurity, crucible,and drop andmanyseparatesamplesusingcruciblesthe105-meter AlargenumberofundercoolingcycleswasperformedonasingleCo 35812 USA; Tom J.Rathz cibles andtheMSFCDrop Tube Undercooling ComparisonofPureCobaltProcessedinCru- 4:20 PM the measurementofsurfacetension. each otherbecauseoftheeffectperturbationE-Mfieldfor been measuredbyE-Mlevitationandfree-fall,weredifferentfrom face tensionderivedbythefrequencyofsurfaceoscillation,whichhad National IndustrialResearchInstitute)droptower. Thevaluesofsur- by free-fallsystemhavebeencarriedoutatthe1.2sHNIRI(Hokkaido been performedundernormalgravitycondition,whilemeasurements M) levitationandfree-fall.ThemeasurementsbyE-Mlevitatorhave have beenmeasured,whichweredemonstratedbyelectromagnetic(E- periment. Thecomparableresultsofsurfacetensionmoltensilicon tromagnetic levitatorhavebeencomparedwiththesebyfree-fallex- Theresultsofsurfacetensionmoltensiliconmeasuredbyelec- Tokyo, Japan Utilization PromotionCenter,3-30-16,Nishiwaseda,Shinjuku-ku, Higashi Toyohiraku, Sapporo,HokkaidoprefectureJapan; Institute, Matl.Div., Agcy. ofIndustryandSci.Tech., 2-17Tsukisamu- Kamada Orihashi Minagawa niques ofFree-FallandElectromagneticLevitation Surface Tension Measurements ofMoltenSiliconwiththeTech- 4:00 PM terial, orlightweighthigh-temperatureapplications. a widevarietyofapplicationsincludingfilters,bonereplacementma- before combustionreaction.Thisadvancedmaterialcouldbeusedfor a numberofmechanismsincludinggreendensityandreactantpowders porous, typicallycontaining50-70%porosity. Poresaregeneratedby and glass-formingregionswithinthesamples.Samplesproducedwere and ScanningElectronMicroscopy(SEM)todeterminethecrystalline analysis wasdoneusingX-rayDiffraction (XRD),lightmicroscopy, mine theadiabatictemperature(T the presentwork.Thermodynamicanalysiswascarriedouttodeter- 2 c 2 ; ), andwavevelocityofseveralchemistries.Microstructural Universities SpaceResearchAssociation,MarshallFlight 2 ; Takeshi Okutani 1 ; Yoshiho Ito 1 1 Hoseo University, Dept.ofMatls.Sci.andEng.,Chung-Nam ; Yusuke Goto 2 2 ; UAH, SD47,MSFC/NASA,Huntsville,AL35812USA 1 MSFC/NASA, ScienceDirectorate47,Huntsville,AL 1 ; Takashi Tsurue 1 ; MasatakaSasamori 1 ; 1 Hokkaido NationalIndustrialResearch ad ), andactualcombustiontempera- : Mike B.Robinson : 1 Shinwoo Kim ; Yoshinori Nakata 1 ; HideakiNagai 1 ; 1 2 ; DelinLi Japan Space Richard N. : 1 ; Masaki 1 Hideki ; Keiji 1 ; allurgy NickelBasedSuperalloys Microstructure ModelingofForgedComponentsIngotMet- 2:25 PMInvited Engines, Lynn, MA01910USA Cincinnati, OH45215USA;DavidMourer, GEAircraft Session Chairs: March 14,2000 Tuesday PM Kokomo, IN46904USA 53110 USA;S.K.Srivastava,HaynesInternational, OH 45215USA;D.Furrer, LadishCompany, Cudahy, WI WV 26506USA;K.R.Bain,GEAircraftEngines,Cincinnati, sity, Mechanical&AerospaceEngineering,Morgantown, Program Organizers: perature AlloysCommittee Sponsored by: for WroughtAlloys Affordability: Affordability Technology Advanced Technologies forSuperalloy and NCC8-66isgratefullyacknowledged. tems, willalsobepresented.SupportfromNASAgrantsNAG8-1231 tural phasedistributions,basedonotherliquid-liquidimmiscibilitysys- entire thermaland deformationprocessesduringa forging. Thismeth- operations andfinalcooldown.The microstructureisupdatedforthe in deformation,andstaticstructural changesindwellrestingbetween way: staticstructuralchangesinpreheating, dynamicstructuralchanges evolution evolvedinforgingprocess isconsideredinthefollowing ingot metallurgy superalloys:Waspaloy and718.Themicrostructure tion. Thesamemicrostructuremodeling approachwasusedfortwo were developedtomakeuseofthisinformationforgrainsizepredic- cation oftheforgedcomponents.Microstructuremodelingprocedures obtain thedetailedthermomechanicalhistoriesofeachindividual lo- TheapplicationofFEMtosuperalloyforgingmadeitpossible to Packard Ave., Cudahy, WI53110-8902 USA pany Inc.,Adv. Matls.&ProcessTech., P.O. Box8902,5481S. Inc. 242 HR-120 and230areregisteredtrademarksofHaynesInternational, cessing isalsopresentedanddiscussed.HAYNES®, HASTELLOY®, resistance forHAYNES 230®alloyobtainedvialowtemperaturepro- excellent resistancetostresscorrosioncracking.Enhancedfatigue alloy forboltingapplications.Itshighnickelcontentalsoprovides tially increasedbycoldworkingandagingtoprovideanexceptional aging timerequired.Thestrengthofthismaterialcanalsobesubstan- two-step heattreatmentforthealloythatwillsubstantiallyreduce of thermalexpansion.Recentstudieshavealsopointedthewayfora 242 without theneedforprotectivecoatingsthroughuseofHAYNES® facturers havebeenabletoincreaseusetemperaturesforsealrings to increaseenginecapability. Inanothercase,gasturbineenginemanu- to stainlesssteelsforuseinlandbasedgasturbineapplicationsorder X alloy. Thisalloyhasalsobeenfoundtoserveasasignificantupgrade alloy whichhaspropertiesequivalenttocurrentlyusedHASTELLO® has occurredintheformofalowercostmaterialsuchasHR-120® introduced whichoffer thesuperalloyuserenhancedaffordability. This Overthelastseveralyears,newalloysandprocessinghavebeen Box 9013,Kokomo,IN46904-9013USA Klarstrom New MaterialsandProcessingtoEnhanceAffordability 2:00 PMInvited  alloy, arelativelynew, highstrengthalloywithalowcoefficient  1 isatrademarkofHaynesInternational,Inc. ; 1 Haynes InternationalInc.,Eng.&Tech. Depts.,P.O. Structural MaterialsDivision,HighTem- Kenneth R.Bain,GEAircraftEngines, Location: OprylandConventionCenter Room: CanalC K. M.Chang,West Virginia Univer- : Gangshu Shen 1 ; 1 Ladish Com- : D. L.

TUESDAY PM 88 ; : ; 2 1 , and powder General Electric  1 ; 2 Solar Turbines Inc., Solar Turbines ; Jingyun Zhuang 2 1 ; Paul F. Browning ; Paul F. 1 Central Iron and Steel Re- 1 ; 1 ; David Furrer 2 ; Allen R. Price Zhengdong Long 1 : Howmet Research Corporation, Adv. Tech., Howmet Research Corporation, Adv. 1 ; Gangshu Shen ; ; Zengyong Zhong 1 2 1 Ladish Company, Adv. Matls. and Process Tech. Dept., and Process Tech. Matls. Adv. Ladish Company, 2 Di Feng ; 1 Tammy Marie Simpson Tammy : Bo Dong 1500 S. Warner St., Whitehall, MI 49461 USA; St., 1500 S. Warner San Diego, CA and Process., 2200 Pacific Hwy., Matls. Tech. Adv. 92186 USA to optimize prop- Dual property gas turbine disks were investigated disk. For the rim mate- erties in both the rim and hub sections of the creep rupture life. rial, it is necessary to have good high temperature strength and good low However, for the hub material, both high burst would increase turbine cycle fatigue are important. These properties turbine inlet temperature fuel efficiency by allowing an increase in the In the past, rims and a reduction in the disk cooling air requirements. into dual alloy and hubs of different materials have been consolidated hafnium oxide, may wheels. However, deleterious particles, namely Howmet overall ductility. have contributed to planar failure and reduced with tailored material has demonstrated the ability to HIP bond disks of a planar oxide properties in specific areas without the formation Mar-M 247 LC, IN The alloys investigated were Mar-M 246, layer. 792 Mod5A, and U720 in cast-wrought, Spray-Cast metallurgy form. 4:50 PM of High- the Hot-Workability A New Method to Improve Strengthened Superalloys Nan Rd., Hai search Institute, Dept. of Superalloys, No.76, Xue Yuan dian District, Beijing 100081 PRC A new method based on the optimization of microstructure to improve the hot-workability of high-strengthened superalloys is proposed. By this method, the coarsened gamma prime phase is obtained by lower cooling rate at specified temperature range. This paper discusses the detailed processing, microstructure change, hot deformation flow stress, ductility and recrystallization microstructure. The results show that the new method is very effective to improve the hot- workability of this kind of superalloys. Conducting this process, the the flow stress is lowered deformation uniformity is enhanced greatly, The mecha- and the hot deformation ductility is increased obviously. nism to improve the hot-workability can be explained that the coarsened gamma prime phase optimizes the distribution of alloying elements and lessens its solution strengthening effect at high temperature. Results from disk forging evaluations indicate that through a con- through indicate that evaluations forging from disk Results the microstructural sequence, processing thermomechanical trolled very to provide be controlled can components in the final response inspectability. and ultrasonic grain sizes controlled uniform 4:10 PM Forgings of P/M Rene88DT Grain Size Evolution Modeling Canan U. Hardwicke NY Circle, Niskayuna, One Research Rsrch. and Dev., Corp. Company, 12309 USA; USA 53110-8902 WI Cudahy, 5481 S. Packard Ave., route for powder metal produced engine In a typical processing influencing the component’s is a key processing step disks, forging hence, mechanical properties. The definition final microstructure and processing window to achieve the desired of a forge and heat-treat an iterative process. In this work, a micro- microstructures has been in for Rene88 to describe the change structural model was developed it is isothermally forged and then heat treated. grain size of a billet as a grain size database using isothermal The first step was to develop varied temperature and strain rate. Then em- compression tests with an- developed to describe the deformation and pirical equations were were then integrated with an FEM These equations nealing behavior. microstructure variations for a given part code to predict the local the trial-and-error Application of this model should reduce geometry. superalloys into useful steps in processing R88 and other commercial supported by the AFRL component configurations. This work was under the contract number F33615-95-C-5229. 4:30 PM Disk Applica- HIP Bonding of Multiple Alloys for Advanced tions Michael Fitzpatrick ; 2 ; Carl 1 Special 1 ; 2 Rolls-Royce 3 ; David Furrer 1 Alloy for Fas-      ; M. C. Losch 1 242 ; Dan Wallem 1      ; Xavier Pierron Ladish Company Inc., P.O. Box Ladish Company Inc., P.O. 1 2 ; S. K. Srivastava ; Dan Yates 1 1 Special Metals Corporation, 100 Industry 1 ; 3 L. M. Pike Anthony Banik : : Gaylord Smith Gaylord : ; Sushil Jain Haynes International, P.O. Box 9013, Kokomo, IN 46904 Haynes International, P.O. 2 1 ; 2 Pratt and Whitney, Aircraft Rd., Middletown, CT 06457 USA Pratt and Whitney, 2 Boeing Commercial Airplane Group, Propulsion Sys. Grp., P.O. Box P.O. Propulsion Sys. Grp., Airplane Group, Boeing Commercial 8902, 5481 S. Packard Ave., Cudahy, WI 53110 USA; WI 53110 Cudahy, 8902, 5481 S. Packard Ave., Ln., Princeton, KY 42445 USA; Box 420, Indianapolis, IN 46206 USA Allison, P.O. Powder metal superalloys for turbine disk applications have historically been produced by a two step hot compaction and extrusion sequence to consolidate and refine canned loose powder into consolidated billet material. Powder metal superalloys exhibit relatively low and as such, extrusion process- elevated temperature tensile ductility, ing has provided a means of bulk deformation under predominately compressive stresses. Recent advances in the consolidation of superalloy powders, which incorporate a sub-solidus hot isostatic press (SSHIP) consolidation practice, improves the consolidated billet ductility such that conventional conversion operations can be utilized to produce fine grain billet for subsequent disk forging. This alternate conversion route results in significant reductions in cost and lot size requirements. Metals Corporation, 3200 Riverside Dr., Huntington, WV 25705 USA; Huntington, WV 25705 Dr., 3200 Riverside Metals Corporation, Joe Lemsky One cost-effective solution for the development of materials is the One cost-effective solution for the development Improvements adaptation of an established alloy for new applications. obtained through modi- in certain application-critical properties may be a processing, etc. and can often be explored at fications in chemistry, alloy development pro- considerably lesser expense than a full-scale 242™ alloy HAYNES® gram. An example of this is the adaptation of low-expansion, high- for high-temperature fastener applications. This engines as a seal/ strength alloy is used extensively in gas-turbine standard annealed and containment ring material. However, in the than requisite for cer- aged condition the strength properties are less of a direct-aging process tain fastener applications. The development with significantly im- (cold-work + aging) has resulted in a material Room-tempera- ductility. proved strength while retaining respectable strengths of more than 1750 MPa (250 ksi) are pos- yield ture (RT) the standard annealed sible; this represents a 100% improvement over in strength allows 242™ and aged condition. This dramatic increase it offers a unique combi- alloy to be considered for applications where materials such as alloy nation of properties not found in competing low-thermal expan- 718 or Custom 455®. These properties include cracking in both chloride sion as well as resistance to stress-corrosion for direct-aged and hydrogen environments. Potential applications components in both 242™ alloy include fasteners and high-strength as other demanding indus- aerospace and land-based gas turbines as well is a registered trademark of Haynes trial environments. HAYNES® International, Inc. 242™ is a trademark of Haynes International, Inc. Custom 455®. is a registered trademark of Carpenter Technology Corporation. 3:30 PM Break 3:45 PM Invited Development and Utilization of Press Converted Powder Metal Superalloy Billet USA; tener Applications E. Kelly 3707, MS 4T-80, Seattle, WA 98124 USA Seattle, WA 3707, MS 4T-80, for wide-body aircraft is a critical reduction of the engines Weight of weight saving is possible is through the use issue. One area where increase the strength and fatigue resis- mill processing to dramatically employed in the pneumatic ducting, thereby tance of the material gauge and cost from current alloys possible. making a reduction in alloys for this ducting is INCONEL alloy Since one of the preferred developed to produce a 75 kis yield strength 625, a mill practice was is described in some detail including cer- sheet product. This product the method of manufacture aimed at enhanc- tain steps pertaining to ing fatigue resistance. 3:10 PM HAYNES Development of Direct-Aged 2 odology has been successfully used in various processes such as hydrau- such as processes used in various successfully has been odology on hammer forging and press forging mechanical forging, lic press 718 parts. and Waspaloy numerous 2:50 PM Strength Ducting Though Alloy of Pneumatic Reduction Weight Enhancement

TUESDAY PM 89 prebaked endto end203kAAluminumproduction cellsat Amodification issuggestedonthepresentbusbar designusedinthe Egypt Cairo, GizaEgypt; Shady ration Optimization Towards aMore StableAluminiumCellVia BusbarConfigu- 2:50 PM venture willbeoutlinedandsomepreliminaryresultsshown. structured meshes.Theverychallengingissuestobeovercomeinthis modeling-the complexgeometriesinvolvedareaddressedbyusing un- of thephenomenaandfacilitatestheirinteractionsdirectlyin the taneously. Thisapproachusesafinitevolumeapproximationforeach the modelingofaluminiumcellswhichdescribesallphysicssimul- cial CFDandFEAtools.Inthispaperwewilldescribeanapproach to of theotherphenomena;thishasenabledusestandardcommer- have beenmodeledseparatelyusinguncoupledestimatesoftheeffects resentation simultaneously. Conventionally, aspects oftheprocess provide acomprehensivemodeloftheseprocessesinvolvestheirrep- these phenomenaarecoupledinsomesignificantsenseandso to complexities plusthedevelopmentofstressincellstructure.All of heat transferandphasechange,twofluidflowwitharangeof range. Theseprocessesinvolveelectromagneticfields,coupledwith which actsimultaneouslytoprovideanarrowsatisfactoryoperating Aluminiumcellsinvolvearangeofcomplexphysicalprocesses Process Analysis,Wellington St.,Woolwich, LondonSE186PFUK Williams Cross Multi-Physics ModelingofAluminiumReductionCells 2:25 PMInvited nism. and asimplephysicalexplanationcanbegiveforthedrivingmecha- field andanode-cathodeseparationarecrucialindeterminingstability, mal modeshavesimilarfrequencies(resonance).Thecellmagnetic disrupting theefficientoperationofcell,particularlyiftwonor- however couplesthenormalmodesandmayleadtoamplitudegrowth, are non-interactingandofconstantamplitude.TheLorentzforce mal modes,whichintheabsenceofaforcefieldorenergydissipation pressing the(smallamplitude)wavesystemasacombinationofnor- the Lorentzforceaddsanewtwist.Stabilitycanbeanalysedbyex- be excitedinthesystemisaclassicalproblemhydrodynamics,but minium) inarectangularcontainer. Determiningthewaveswhichcan rior canberegardedapproximatelyastwo-fluidsystem(cryolite/alu- which candestabilisethecryolite-aluminiuminterface.Thecellinte- generates anassociatedmagneticfield,andhenceaLorentzforce-field Theelectriccurrentflowingthroughanaluminiumreductioncell Private Bag3105,Hamilton2001NewZealand Shin Metal PadInstabilitiesinAluminiumReductionCells 2:00 PMInvited Director, MountMacedon,Victoria 3441Australia Session Chair: March 14,2000 Tuesday PM Engineering, Halifax,NSB3J2X4Canada University, DepartmentofMiningandMetallurgical Auckland, NewZealand;GeorgesJ.Kipouros,Dalhousie Department ofChemical&MaterialsEngineering, Program Organizers: Sponsored by: MHD/Modeling Aluminum ReductionTechnology: 1 ; 1 1 ; K.Pericleous ; W. Ismail Alfred DavidSneyd 1 ; 1 University ofGreenwich,Ctr. forNumericalModeling & 1 Light MetalsDivision,AluminumCommittee ; F. M.El-Dawi Jeff Keniry, AluminationConsulting, 2 Egyptalum-Aluminium Company of Egypt,Cairo, : M.F. El-Demerdash 1 ; L.Leboucher Location: OprylandConventionCenter Room: Sewanee John Chen,UniversityofAuckland, 1 ; 1 University ofWaikato, Dept.ofMath., 2 ; 1 1 Cairo University, FacultyofEng., ; T. N.Croft 1 ; A. Adly 1 ; V. Bojarevics 1 ; S.E.Abu- : : D. Mark 1 ; A. trical Eng.,Spl.Independentei313,Bucharest77206Romania; Models: ATutorial Thermo-Electric Designofa400kACellUsingMathematical 3:15 PM are presentedindetailthepaper. figurations, computedfieldsresults,andcorrespondingstabilitylevels several busbarconfigurationswereconsidered.Detailsofthosecon- design ascomparedtothebasedesign.To reachthemodifieddesign, field component,andmorestablestabilityfiguresforthemodified Results showedmoresymmetricmagneticfieldsespeciallyforvertical PACEM3 packageformagneticfields,forces,andstability figures. currently workingandthemodifiedconfigurationarecomputedusing EGYPTALUM, Nage-Hammady, Egypt.Boththebaseconfiguration industrial electrolysiscells. 12,5 MWh/tisachievable,which will probablybeaworldnoveltyfor that theFaradayefficiencyshould increase.Aspecificconsumptionof the overvoltagesduetoanodiceffects willbeloweranditisexpected will becontrolledbyamicroprocessor. Underthesenewcircumstances symmetrization willhaveacentral, punctualsupply, andeachofthem tal cellsareopencells).Inthesecondhalfof1999with type ofindustrialcellsworkinginsymmetricalfield.(Theexperimen- 13 MWh/tisaremarkableparameter,ifonetakesintoaccount the Aluminium Works. A specificconsumptionofelectricenergy below symmetrical cellsand122intheelectrolysisHallno9of the month isOctober1996.Themediahavebeendoneongroupsof 6 the graphicsthereismonthaveragedvaluerefersto.Thefirst and atwhichthecellshavefunctionedinstability).Onxaxes of ages (3.65Vhasbeenthelowestreferencevoltagethattested notice thatthesecellscanfunctionatrelativelylowreferencevolt- tities havebeengraphicallyrepresented.(Figures1and2).Onecan voltage droponcellhavebeenrecorded,andthevaluesofthesequan- efficiency oftheelectrolysisprocess(Faradayefficiency),and the The variationofthespecificconsumptionelectricenergy, ofthe one year,becausetheyhaverelativelyimportantvariationsintime. been averagedon30-dayperiods(monthly),6-monthand done withspecialprecaution.Thefunctioningcharacteristicshave the cellwouldbemodified.Thedecreasesofvoltageshavebeen be reducedonlythereferencevoltage,becausethermalbalanceof the last910days(twoyearsandahalf).Atanindustrialcellitcannot tains themaintechnicalindicatorsofcellswithsymmetrizationfor technology insymmetricalfield.Thus,atpresent,thedatabasecon- ods oftimehavebeennecessarytodemonstratetheadvantages determines onlythedecreaseofcurrentsthroughrods.Longperi- second, duetotheaccumulationsofgasesunderanodes,andwhich are nowaves.Thereonlyoscillationswithafrequencyofabout appeared. Thisisaproofthatonthesurfaceofmoltenmetalthere 3.65 V, andoscillationsofthecurrentswithlongperiodshavenot lower referencevoltages.Thevoltagehasbeendecreasedto the cellsthatworkinsymmetricalfield,instabilitiesappearat stability whenthereferencevoltagedecreasesbelow4V. Inthecaseof currents oftheanodicrods.AstandardcellinHallno9losesits This facthasbeenshowedexperimentallybytheoscillographyof of thesurfacemoltenaluminiumhavebeenstronglydecreased. Inthecellswithsymmetricalmagneticfieldverticaloscillations ALRO S.A.,GeneralManager, Str. Pitesti116, Slatina, Romania Panaitescu Electrolysis CellswithSymmetricMagneticField 3:50 PM 3:40 PMBreak slice processmodel. as wellthenewlydevelopeddynamicthermo-electric2D+fullcell full cellslicemodelandthe“lumpparameters”dynamicprocess of modelsusedarethenowstandardsteadystatethermo-electric3D example isamodernprebakedPBFcellrunningat400kA.Thetype cell liningdesign.Thepaperisstructuredasatutorial,theselected ematical modelstoproduceathermallybalancealuminumreduction Thispaperpresentsatypicalapplicationofthermo-electricmath- Jonquiere, QuebecG7S2M9Canada 1 ; G. Dobra : Marc Dupuis 2 ; 1 University PolitehnicaofBucharest,Elec- 1 ; 1 GeniSim Inc.,3111 AlgerSt., : 2 S.C. A.

TUESDAY PM 90 : ; 1 ; Werner K. ; Werner 1 ; Werner K. Fischer ; Werner 1 ville A ; Raymond C. Perruchoud 1 Box 362, R & D Carbon Limited, P.O. 1 University of Auckland, Chem. and Matls. 2 ; Markus W. Meier ; Markus W. ; Morten Sorlie, Elkem ASA Research, Morten Sorlie, Elkem 1 2 Location: Opryland Convention Center Nigel R. Turner, Tarconord Group, Bitmac Tarconord Nigel R. Turner, Light Metals Division, Aluminum Committee Light Metals Division, Kirstine L. Hulse : ; Barry J. Welch 1 R&D Carbon Limited, Rsrch. and Dev., P.O. Box 362, Le Châblé, Box 362, Le P.O. R&D Carbon Limited, Rsrch. and Dev., Fischer Eng., Private Bag 92019, Auckland, New Zealand Traditionally recipes have used 3000 Blaine dust in the carbon paste due to limitations that existed previously in the processing equipment, particularly in the classifying, weighing, preheating and mixing stages. The optimum processing conditions will change for different recipe conditions and different equipment capabilities. For a given paste plant design, the recipe should be chosen requiring optimum processing conditions as dictated by the plant equipment limitations. This investigation demonstrates how the paste consistency of different recipes can be altered through adjusting the parameters in the preheating, mixing, levels of anode quality. forming and cooling stages to produce differing 2:00 PM to the Smelters Coke Characteristics from the Refiners 1 Sierre, VS 3960 Switzerland anode behaviour Modern smelter technologies require consistent and net carbon consump- ending with long anode cycles for low gross resistant anodes as tions. Therefore high density but thermal shock have been developed in well as high performance forming machines material side the coke the last decade to match this goal. From the raw and bulk density properties like: pulverizing factor and grain stability, production of crack free and resiliency are becoming critical for the preparation and pitching anodes as they influence not only the fines the green anodes after aspects but also the extent of lamination of These mechanical and forming and the crack propagation resistance. of resid oil but also by physical properties are influenced by the type of the coke macro- the coking and calcining conditions. The impacts structure (isotropy) from the coking to the calcining steps are reviewed. The blending aspects of green or calcined cokes with different macrostructures and sulfur content are also reviewed taking into ac- This knowledge allows optimiza- count the anode burning behaviour. tions of the coke production from the refineries to their usage in the carbon plant. 2:30 PM Process Adaptations for Finer Dust Formulations: Mixing and Forming Sierre CH3960 Switzerland; fields in various industrial apparatus for aluminum manufacturing. The manufacturing. aluminum for industrial apparatus in various fields and optimization operation for both cell were implemented models proof the transfer investigations Computer developing. new designs in anode carried a gas evolving cells with reduction in aluminium cesses conduct does not practically direction. A gas bubble the following of the elec- insulates a certain part and it therefore electrical current of these model for the analysis The 3d mathematical trode surface. the growth equation, describing comprises a differential phenomena equation time and the Laplace of the bubble shape versus and changes relationship basis of this model the potential. On the for the electrical of in electrolyte and shape, size and number between voltage drop bubbles is obtained. Mill and Green Carbon Technology: Anode Baking Sponsored by: Program Organizers: N-4675 Norway; Christian Dreyer, Kristiansand Vaagsbygd, Jean De Maurienne 73303 France St Aluminium Pechiney, Tuesday PMMarch 14, 2000 Knox Room: Session Chair: 6UR UK Limited, Scunthorpe, North Lincs DN15 Raymond C. Perruchoud ; 1 PSC PSC : S. 1 1 ; ; 1 1 Vladimir V. ; ; A. Moraru 1 1 P. V. Polyakov V. P. ; 1 ; K. F. Nikandrov ; K. F. 1 A. Panaitescu : : A. G. Barantsev ; A. G. Barantsev 1 ; T. V. Piskazhova V. ; T. 1 University Politehnica of Bucharest, Electrical Eng., Electrical of Bucharest, Politehnica University 1 ; ; V. V. Pingin V. ; V. 1 1 ; V. C. Mann ; V. 1 Krasnoyarsk Aluminum Plant, Krasnoyarsk 660111 Russia The experience in software developing and application for various Russian aluminium plants is confirmed that parallel with universal software complexes, relatively small mobile programs for personal computers have the right to exist. The interface of these programs makes it possible for technologists and designer to work with them without any thorough training in the area of computer technique. Effective algorithms and relatively high speed of calculations allow to check a lot of versions. The developed complex was applied for calculation and analysis of 2d and 3d distributions of thermal and electrical Yurkov 660111 Krasnoyarsk Aluminum Plant, Krasnoyarsk Russia metal has been A model of the process of reduction of aluminum the dynamic developed allowing to describe in the first approximation ACD, bath chemistry, process variables such as bath temperature and and others. A math- frozen cryolite ledge thickens, operating voltage ematical model comprises several sub-models dedicated to different aspects of reduction process. Based on the presented mathematical model a virtual (“soft’) cell was developed. A virtual (“soft”) cell can be used to run analyses of various situation in a real (“hard”) operating cell, for prior testing the process control algorithms and establishing optimum operating conditions for the newly designed cells and person- nel training. Some fragments of the model can be incorporated into the process control system for doubly connected temperature/ratio control. 5:05 PM and Its Application for 3D Thermo-Electric Field Modeling Tool Energy Regime Simulations in Aluminum Reduction Cells A. Sherbinin Spl. Independentei 313, Bucharest 77206 Romania 313, Bucharest Spl. Independentei oscillations of cells the vertical aluminum reduction In Hall-Heroult energy effi- on the current and have a great influence the metal pad least average order to establish the reduction process. In ciency of the of the cell, a quiet functioning distance which ensures anode to cathode in differ- the metal pad waves is necessary to survey a on-line method the cell with pre-backed anodes the electroly- ent operation stages. In several-usually four-stubs embedded in each sis current is lead through 1. By measuring the beam to aluminum pad anode block, as in Fig. of currents, and by using an adequate model voltage drop and the stub the resistance, including the electrolyte layer, the anode block quart electrolyte bath below each anode quart can average thickness of the basis a monitoring system was developed, using be established. On this system, which is measuring the stub currents, an 64 channel acquisition of 10 ms. After conditioning the acquired with a sampling interval in space, for each set of data can be shown signals and by interoplating surface. When are not known the channel scale the profile of the pad drop, a self-calibration of the data is used, factors stub current/voltage operation section. Several post-processing accomplished on a “quiet” the acquired or filtered and plotting facilities are provided: plotting of separated or grouped signals, versus the time moment of acquisition, signals on anode together on anode, plotting of the self-calibrated surface, determined rows, plotting of animated 3D aluminium pad’s 3D aluminium pad’s with 64 stub signals, and plotting of animated last two processing are surface, determined with 16 anode signals. The vary inversely with based on the assumption that the signals (currents) an weighted, direct and the electrolyte layer thickness. For the 3D plot points which corre- inverse, interpolation is used between the centre function griddata from spond to the acquired signals, using the Below two 3D plots are shown (Fig.2 and Fig. 3), which MATLAB. cellfq.m for 64 stub illustrate the results obtained with the functions: last plot is more poor in signals and cellgq.m for 16 anode signals. The information is more details as the first one, because also the primary The 3D plots may be animated, according to the duration of the poor. the moving aluminium acquisition cycle (0.64 s), what allows to follow waves in the cell. 4:40 PM of Electrolysis Model of Process 4:15 PM 4:15 Re- in the Aluminum Waves Metal Pad of the Visualization Anodes Pre-Baked Cell with duction I. Panaitescu

TUESDAY PM 91 consumables tremendously. increase thereliabilityofsystem andcancuttherunningcostsfor temperature. Specialinstrumentation likeIR-sensorsandopacitymeters and forfinetuningoftheFiring IndexModuletothefinalbaking sion ofcriticaltemperaturegradients intheanodeduringpitchburn the anodetemperaturebyadynamicalmodelisusedforsupervi- actual fluesituationandbakingcondition.Theon-lineprediction of the specificfurnace.On-linetestsequencesadaptsthisstructureto the non parametricneuralnetworkmodelreproducesthebasicstructure of the volatilecomponentsandincreasedirectlyfuelefficiency. A and theFloodingMonitorModuleensurecompletecombustion of improved. AdvancedcontrolalgorithmsusingtheFiringIndexModule ciency, thequalityconsistencyandproductivitycanbehighly introduction ofanadvancedfiringandcontrolsystemthefueleffi- emissions maynotsatisfytheenvironmentalauthorities.With the the pollutioncontrolaccordingtoCO,NOxandunburnedcarbon automation. Duetothissituationthefuelefficiencycanbepoorand these furnacesarestillmanuallycontrolledorjusthaveaverybasic ready alongtimeinoperationfortheproductionofanodes.Many Intheprimarysmelters,alotofopenpitbakingfurnacesareal- Germany Detlef Maiwald Advanced FiringandControlSystem-BenefitsResults Improvement ofExistingAnodeBakingFurnacesbyUsean 3:55 PM 3:45 PMBreak amples oftheeffectsrawmaterialchangestobakedcarbon. anode core.Thispaperwilloutlinethemethodsusedandgiveex- devised amethodoftrackingtherawmaterialsfromdeliverytobaked Rodding totheanodeperformanceincell.CenturyAluminumhas tracking rawmaterialschangesthroughtheGreenMill,Baking,and in theincomingcokeandpitch.Smeltershavealwayshaddifficulty produce aconsistentlyhighqualityproductwhileexperiencingchanges in asmelter. ThechallengeforCarbonPlantsaroundtheworldisto weight, pitchdemand,oroptimalaggregatesizingamongotherfactors quantity. Thesechangesaffect netcarbon,anodedensity, return butt and pitchprocessingfacilitiesarefrequentlychanginginquality ing businessclimates,thesourcesoffeedstockstocokecalcining the steelindustry’s production,changingproductdemands,andchang- Withnewenvironmentalregulationseffectingcokers,changesin 26264 USA tury Aluminum,PrimaryProducts,P.O. Box98,Ravenswood,WV ode CorePerformance A MethodtoCorrelateRawMaterialPropertiesBakedAn- 3:20 PM of determiningbakelevel. review overallperformanceofatypicalpitdistributionandthemethod used tomaximizetheefficiencyofbakedcarbon,method mize bakedanodeperformance.Thispaperwilldetailtheprocedures properties canthenbedeterminedandbakelevelsadjustedtomaxi- Carbon equation,thebestpossiblecombinationofbakedanodecore properties toabakelevelindicator. ThenusingtheR&DCarbonNet nace operation.Themethodincludescomparingbakedanodecore maximum anodeefficiencythatcanbeachievedbytheBakingFur- ucts Divisionhasdevelopedasystematicmethodtodeterminethe optimized toreducenetcarbonconsumption.Century’s PrimaryProd- anode’s behaviorintheelectrolysisprocesseachofthesestepsmustbe preparation, mixing,forming,andanodebaking.To improvethe many factorsincluding,butnotlimitedto,rawmaterials,aggregate Thecarbon’s performanceinthereductioncellisinfluencedby WV 26164USA 1 Anodes A MethodtoDeterminetheOptimalBakingLevelofCarbon 2:55 PM pressed anodes. This hasbeenexecutedonpilotandproductionscale,vibrated Century Aluminum,PrimaryProducts,P.O. Box98,Ravenswood, : Marilou McClung 1 ; 1 LVE Verfahrenselektronik GmbH,EssenD45138 : Marilou McClung 1 ; J.AnthonyRoss 1 ; J.AnthonyRoss 1 ; GeraldChovanec 1 ; 1 Cen- 2 ; : Southwire Company, Hawesville,KY42348USA Session Chair: Room: Mississippi March 14,2000 Tuesday PM 40202-2823 USA Corporation, DepartmentofEngineering,Louisville,KY USA; JamesN.O’Donnell,CommonwealthAluminum Corporation, GMPowertrainGroup,Pontiac,MI48340-2920 Program Organizers: Sponsored by: Operations Cast ShopTechnology: MeltShop ing System Improvements inAlbrasBakeFurnacesPackingandUnpack- 4:20 PM Charles R.Emond Adapted tothe Specific NeedsofaCastShop Multi-Functional, Articulated Vehicle whichcanbeEasily 2:30 PM these problemswillbeaddressed in thepaper. No topdrainofskull;7)Environmental problems;8)Safety. Eachof (below 675 thermitting dross;4)Presscould notprocesslowtemperaturedross life ofpresshead;3)Presscouldnotprocesshot(over900 problems withthedrosspress:1)Drossstickingtopresshead;2)Short 1895. Fromourinitialtrials,therefore,wehadidentifiedthefollowing operating in1995wasnotmuchdifferenttotheoriginalmachine of or thermittingdross.Ourconclusionwasthatthemachinewewere medium temperaturedross,weexperiencedseriousdifficultieswith hot Ltd startedtouseadrosspress.Althoughwehadsomesuccesswith (132mbls) ingotperyear. During1995weat J.McIntyreAluminium is theUKslargestrecyclerofaluminium,producing60,000tons Experience with1stGenerationMachineJ.McIntyreAluminiumLtd break, andmeltdownswithinthesystemoftenoccurred.Operating ture ofdrossandassociatedsticking.Steelcastingstendedtocrack Early systemsfailedduetotheproblemsassociatedwithhightempera- furnace intocastironorsteelpotsandsqueezedbyahydraulicram. Dross presseshavebeenusedsince1895.israkedfromthe combined tomaximizemetalrecovery. FirstGenerationMachines of thedrosscooler,pressandstirrerhavebeen have evolvedovertheyears.Thispaperdescribeshowbestaspects Manydifferenttechnologiesforrecoveringaluminiumfromdross gland Harrimans Ln.,Dunkirk,Nottingham,NottinghamshireNG36JREn- Perry The DevelopmentoftheModernDrossPress 2:05 PM 2:00 PMIntroductoryRemarks creasing morethanfourtimesthepackingcokesuctioncapacity. the pneumaticconveyorphenomenon,breakingparadigmsandin- internal solutionusingamathematicalmodeltoanalyzeandoptimize the CarbonPlantEngineeringGrouphasprojectedanddevelopedan head cranesof15t/hcokesuctioncapacity. Thispapershowshow the heattransfer. Eachfurnaceisservicedbythreemultipurposeover- which petroleumcokeispackedtoavoidairoxidationandfacilitate deep andaccommodatesfourlayersofthreeanodeblocks,around walls throughwhichthefurnaceisfired.Thecellaboutfourmeters composed bysectionsmadeupofsixcellsseparatedpartitionsflue ALBRASoperatesfourring-typebakefurnaces.Eachfurnaceis Brasil Carbon Eng.Grp.,Rod.PA483, Km21,Barcarena,Para68447-000 1 ; 1 J. McIntyreMachinery, Sales,UnitG,AcornParkInd.Estate, : ° C); 5)Inconsistenton-sitemetal recovery frompress;6) Paulo DouglasVasconcelos Light MetalsDivision,AluminumCommittee Julian V. Copenhaver, NSADivisionof 1 ; LucBoivin Location: OprylandConventionCenter Paul Crepeau,GeneralMotors 2 ; 1 Multi-Functional Vallee Inc., 310 1 ; 1 Albras AluminioBrasileiro, : : Serge Desgagne Ophneil Henry ° C) or 1 ;

TUESDAY PM 92 ; 1 ; Juan de Dios 1 ; Stephen L. Houser 1 Alfredo Flores : Young E. Lee Young : CINVESTAV, Unidad Saltillo, Carretera Saltillo Monterrey, Unidad Saltillo, Carretera CINVESTAV, 1 ; 1 Eramet Marietta Inc., State Route 7 South Riverview Dr., P.O. Box P.O. Dr., Eramet Marietta Inc., State Route 7 South Riverview model presented model rolled scrap feeding interest when of direct could be into molten aluminium. PM 4:15 Alumi- Removal of Molten Study on the Antimony A Kinetic Powder Injection num by CaSi Castrejón 25900 Mexico Arizpe, Coahuila Km. 13, Ramos of sodium or over the behaviour effect of antimony The deleterious addressed in eutectic phase has been modifiers of the AlSi strontium as through the last few years. Nevertheless, different technical papers of publications related to the development there are not enough from molten aluminum alloys. In this processess to remove antimony the the experimental results obtained after sense, this paper describes of based on the submerged powder injection application of a technique antimony from molten aluminum. Kinetic CaSi blends, to remove performed as a function of powder flow rate- measurements have been ratio, temperature of the bath, and powder size. to-carrier gas flow rate of 65% were reached for the best combinbation Efficiencies in the order so it was possible to sustain that the method of operating parameters, reaching the objective proposed. studied is adequated for 4:40 PM Ele- for High Melting Point Transition Dissolution Mechanism ments in Aluminum Melt 1 299, Marietta, OH 45750 USA Fe, and Mn in aluminum Alloying transition elements such as Cr, to cast shop opera- melt with a consistent performance is a challenge This study is to density. tors because of their higher melting point and for Cr, Fe, Mn by provide an understanding of the alloying process The dissolution behaior. examining their alloying performance and melt was deter- alloying performance for Cr, Fe, and Mn in aluminum elements in alumi- mined by measuring the recovery of the alloying the microstruc- num melt and the dissolution behavior by examining alloying pocess. It was tures of the interrupted samples during the for Fe and Mn than observed that the time for a full recovery is shorter condition and that their for Cr in a similar aluminum melt stirring additives as well as recoveries are affected by the design of the alloying melt. The variation of by the hydrodynamic condition of aluminum shows that the alloying the microstructures with the processing time dissolution sequence of i additives for Cr, Fe, and Mn go through the in aluminum melt but ncubation, exothermic reaction, and dispersion The dissolu- from each other. their dissolution kinetics are different process of Cr, Fe, and tion mechanisms are proposed for the alloying Mn in aluminum melt. ; : ; 1 1 Norwegian 1 ; 1 Alcan Primary Met- Alcan 2 ; John van Heeswijk 1 ; Mohamed Guermazi 1 Hoogovens Research and 1 Ålesund College, Ålesund 2 ; 2 ; Thorvald Abel Engh Wim Boender Wim 2 Claude Allaire : : ; Jan Quisthoudt 2 ; Frede Frisvold 1 Hoogovens Aluminum NV, A. Stocletlaan 87, Duffel B-2570 Belgium A. Stocletlaan 87, Duffel Hoogovens Aluminum NV, Ecole Polytechnique of Montreal, CRIQ Campus, 8475 Christophe Ecole Polytechnique of Montreal, CRIQ Campus, University of Science and Technology, Dept. of Matls. Tech. and Dept. of Matls. Tech. University of Science and Technology, Electrochem., Trondheim N-7491 Norway; N-6025 Norway Metal losses during remelting is common when recycling aluminium. Reduction of these losses could give a substantial economic gain. Ex- periments with continuous feeding of aluminium plates into molten aluminium have been performed. A simple steady-state mathematical model has been developed that gives the temperature profile and the penetration depth into the melt as a function of the feeding velocity, superheat, and the heat-transfer coefficients from melt to solid and from a solidified shell to the plate. A criterion for shell formation is also formulated.The results can be applied to understand more complex systems whereshredded scrap is fed into molten aluminium. The In the cast house of Hoogovens Aluminium NV in Duffel, Belgium, In the cast house of Hoogovens Aluminium furnaces. A smooth nearly all melting furnaces are channel induction inductors that are the operation of these furnaces is important. The extremely reliable and heating elements of these furnaces must be An induc- predictable. Hence inductors are monitored systematically. it is similar Electrically, tor is an a.c. device for heating liquid metals. Its resistance and reactance depend to a short-circuited transformer. and secondary circuits. on the resistances and reactances of its primary resistance and reactance are dependent on the The secondary circuit’s shape and the size of the inductor channels. The changes of these channels due to wear or clogging can be assessed measuring the resis- A comparison with the tance and reactance of an operating inductor. regular mechanical measurements has shown that the electrical method accuracy to monitor state with sufficient determines an inductor’s geometry changes. Therefore it has been adopted in daily operations. 3:45 PM Break 3:50 PM Remelting by Continuous Feeding of Rolled Scrap into a Melt 2 Dirk Van Nieuwerburgh Dirk Van Box 10000, 1970 CA IJmuiden The Netherlands; Development, P.O. Snorre Farner Colomb Rd., Montreal, Quebec H2M2N9 Canada growth may take place In aluminum treatment furnaces, corundum of their refractory at the metal line which promote the deterioration may increase the sidewall. While conventional non-wetting additives the metal line in such resistance to corrosion of refractories below at the high operating furnaces, their efficiency is significantly reduced line. The purpose of temperature conditions prevailing at their metal permit to protect refrac- this paper is to present a new additive which in the above application. tories against the action of corundum growth 3:20 PM of an Inductor of a An Electrical Method to Monitor the State Channel Induction Furnace 1 Principale, St-Alban, Québec G0A 3B0 Canada; G0A 3B0 Québec St-Alban, Principale, G7S4LS Canada Quebec Jonquiere, Box 1500, P.O. Project, als, Alma for adapted equipment, mobile specialized use of efficient, The posi- have a major, can purposes, and charging maintenance furnace perform Forklift trucks cannot operations. on cast shop’s tive impact can economi- Customized tools required in a cast shop. all the tasks of the cast operators, the quality the safety of the furnace cally ensure reducing the refractory life, while productivity and metal, improve of a paper describes the advantages required. This number of vehicles A quick- adapted to the cast shops. articulated vehicle, multi-functional connects semi-automatically onto a vari- action attaching mechanism perform various tasks such as scrap charg- ety of modular tools which stirring, skimming and cleaning the fur- ing, alloy material charging, clamped to the vehicle and hydraulically nace. The tools are rigidly and positioning. The operator can com- activated for tilting, rotating ever having to leave the vehicle. He has plete his work cycle without all times while enjoying the comfort of an air- an unobstructed view at in and ergonomics have played a major role conditioned cabin. Safety the design of the equipment. 2:55 PM Against Corundum Growth in Alumi- Protecting Refractories Furnaces num Treatment

TUESDAY PM 93 fatigue crackgrowth ofsmallcracks(~20 distribution enables thepredictionoffatigueproperties. Astudyof derstanding ofthesmallcrackbehavior andknowledgeoftheporesize initiate predominantlyfrommicroshrinkage pores.Therefore,anun- num specimensisdominatedby propagation ofsmallcrackswhich Forawiderangeofstressamplitudes, thefatiguelifeofcastalumi- MD 3182/SRL,20000RotundaDr., Dearborn,MI48121USA Arbor, MI48109-2136USA; sity ofMichigan,Dept.Matls.Sci.andEng.,2300Hayward,Ann Alloy the BehaviorofSmallFatigueCracksinaCastAluminum The InfluenceofHeatTreatment andSolidificationRateon 2:25 PM light oftheseprerequisites. intrusions. Theexistingmodelsofcrackinitiationareaccessedin the sions includinghardeningofmaterialaroundtherootsurface sion root,and(iii)irreversibleslipprocessesaroundthesurfaceintru- peak topography, (ii)locallyhighercyclicplasticstrainattheintru- prerequisites forthemicrocrackinitiationare(i)expressivenotch- sents onlyoneofthemodescyclicsliplocalisation.Thenecessary but thissliplocalisationneednotbeduetothePSBs;PSBsrepre- plays alwaysthecrucialroleininitiationoffatiguemicrocracks, coarse surfacehill-valleytopography. Thusthe cyclic sliplocalisation fests itselfbyotherformsofslipactivityleadingtotheformation critical rangeand/orunderhightemperaturesthecyclicplasticitymani- stacking faultenergycycledunderstressesand/orstrainsoutsidethe perature. Forsinglecrystalsofnotsuitableorientationsand/orlow plitudes withzeroornear-zeromeanstressesatnottooahightem- energy cycledatarelativelynarrowrangeofstressand/orstrainam- crystallographic orientationsandofsufficientlyhighstackingfault of persistentslipbands(PSBs)isconfinedtosinglecrystalssuitable cyclic plasticityandincrackinitiation.Itisshownthattheformation emphasis willbeplacedontheroleofcyclicsliplocalisationin fcc singlecrystalsusedinengineeringpracticewillbediscussed.The Initiationoffatiguecracksbothinmodelfccsinglecrystalsand Republic Ludvik Kunz Fatigue CrackInitiationinFCCSingleCrystals 2:00 PM Laboratory, Washington, DC20375USA Brno, CzechRepublic;K.Sadananda,NavalResearch Session Chairs: March 14,2000 Tuesday PM Engineering, Urbana,IL61801USA University ofIllinois,DepartmentMaterialsScienceand Engineering, Tempe, AZ85287-6106USA;J.K.Shang, University, DepartmentofMechanicalandAerospace Philadelphia, PA 19104USA;PedroD.Peralta,ArizonaState vania, DepartmentofMaterialsScienceandEngineering, Ontario Canada;CharlesMcMahon,UniversityofPennsyl- Department ofMetalsandMaterialsScience,Toronto, Program Organizers: Mechanical BehaviorofMaterials Critical Technology Sector, StructuralMaterialsDivision,Jt. Sponsored by: Initiation, GrowthandFatigueLife(I) Professor CampbellLaird:Crack Materials; ASymposiuminHonorof Cyclic DeformationandFatigueof : Michael J.Caton 1 ; 1 Institute ofPhysicsMaterialsAsCR,Brno,Czech ASM International:MaterialsScience L. Kunz,InstituteofPhysicsMaterials, Location: OprylandConventionCenter Room: CanalA 1 ; J.Wayne Jones Zhirui Wang, UniversityofToronto, 2 Ford MotorCompany, Matls.Sci.Dept., 1 µ ; JohnE.Allison m to2mm)incast W319- : Petr Lukas 2 ; 1 Univer- 1 ; Mixed-Mode ThresholdsinHigh-CycleFatigue 4:05 PM 3:40 PMBreak the coppersinglecrystals. Coffin Mansonequationprovidesalowerboundforthefatiguelifeof Manson equationforpredictingthefatiguelife.Itisseenthis modeled asafunctionofthecumulativestrainandleadstoCoffin known. Thegrowthkineticsofthepopulationcrackscanbe The extentofthis“strainrobbing”regionunderloadcontrolisnot adjacent PSB’s ofstrainandhaltthegrowthcracksinthosePSB’s. cracks alsoshowatendency, similartothatin straincontrol,to“rob” “skipping” onasecondaryslipsystemtoanadjacentPSB.These PSB’s. ThecracksthengrowalongthePSB’s withtheoccasionalcrack strain control,thesecracksarealmostexclusivelyfoundinmicro are foundtonucleateinPSB’s underloadcontrol. However, unlikein the kineticsofstage-Icrackgrowthcanbedeveloped.Stage-Icracks dicting fatiguelivesofcoppersinglecrystalsbasedonthephysics and requiresanunderstandingbeforeaunifiedmethodologyforpre- ior ofthestage-Icracksunderloadcontrolissignificantlydifferent understood. However,thePSBbehaviorandconsequentlybehav- tiation andpropagationofstage-Icracksunderstraincontroliswell stage-II behaviorheraldstheadventoffracture.Theini- magnitude ofthelifeincoppersinglecrystalsastransitionto Theinitiationandpropagationofstage-Icracksdeterminesthe and AerospaceEng.,Tempe, AZ85287-6106USA Crystals underLoadControl Initiation andPropagationofStage-ICracksinCopperSingle 3:15 PM spacing ofstriationsisalsodiscussed. tion betweentherateoffatiguecrackgrowthin1018steeland with anumberofproposedmodelsforstriationformation.Therela- of striationsformedatvarious of stereographictechniquesinadetailedexaminationthegeometry growth ina1018steelhasbeencarriedout.Thisstudyincludedtheuse Astudyofthefractographicfeaturesdevelopedduringfatiguecrack CT USA 2 Cai On StriationsandFatigueCrackGrowthin1018Steel 2:50 PM strength willbediscussed. sented. Crackgrowthcorrelatingparametersandtheroleofyield small crackgrowthdatafortheT6andT7conditionswillbepre- growth ratesdespitethedifferencesinstrength.Acomparisonof nominally identicalporesizedistribution.Thissuggestssimilarcrack These conditionsexhibitconsiderablydifferentyieldstrengthsand similar fortheover-aged(T7)andpeak-aged(T6)conditionsofW319. terestingly, apreviousstudyrevealedthattheS-Ncurvesarevery slowly solidifiedmaterial,whichpossessesaloweryieldstrength.In- rate onpropagationbehavior. Fastercrackgrowthoccursinmore a significantsmallcrackeffectaswellaninfluenceofsolidification T7 Al,acommercialAl-Si-Cualloyusedinautomotivecastings,showed puted intermsof finer-scale bimodal microstructure,providedthedriving forceiscom- ∆ the modeIthresholdisdecreased withincreasingmode-mixity(at mode (modesI+II)versus I conditions.Itisshownthatwhereas lamellar microstructures,withemphasis onbehaviorundermixed- load-ratio conditions,inaTi-6Al-4V bladealloywithbimodaland of thefatiguethreshold,underrepresentative highfrequencyand cannot occurwithin~10 design mustbebasedonaHCFthreshold,suchthatcrackpropagation eign objectdamage.Duetothehighfrequencies(>1kHz)involved, disks, initiatedatsmalldefectsoftenassociatedwithfrettingorfor- bine enginefailures.Itresultsfromfatigue-crackgrowthinbladesand High-cyclefatigue(HCF)isaprimecauseofmilitaryaircrafttur- Mineral Eng.,Berkeley, CA94720USA R. O.Ritchie delphia, PA 19104USA; Campbell Laird University ofConnecticut,Dept.Metallu.andMatls.Eng.,Storrs, K II 1 / ; ArthurMcEvily ∆ K 1 ratiosfrom0to2,atload from0.1to0.8),inthe 1 ; 1 ; 1 ∆ University ofCalifornia,Dept.Matls.Sci.and 1 G bysummingup thecontributionsinbothmodeI University ofPennsylvania,Dept.MSE,Phila- 2 ; 9 cycles.Inthiswork,weexaminethenature 1 2 Motorola Corporation,Austin,TXUSA; Arizona StateUniversity, Dept.ofMech. ∆ : K levels.Theresultsarecompared Ahsan Jameel : 1 ; PedroPeralta J. P. Campbell : H. 2 1 ; ;

TUESDAY PM 94 : Stanford 1 The Ohio 1 ; 1 ; 1 Robert Sinclair ; Michael Mills 2 : Diane E. Albert, Los Alamos National Los Alamos Diane E. Albert, Room: Canal D Convention Center Location: Opryland Diane E. Albert, Los Alamos National Diane E. Albert, Los Structural Materials Division, Physical Materials Division, Structural ; Jörg M.K. Wiezorek 1 University of Pittsburgh, Dept. of Matls. Sci. and Eng., Pittsburgh, State University, Matls. Sci. and Eng., Columbus, OH 43210 USA; State University, 2 USA PA Alloys based on the intermetallic compound TiAl can be heat- treated to yield various forms of microstructure, among which the lamellar version offers advantages in terms of optimizing strength. This optimization is associated with the scale of the microstructure that can be effected by heat-treatment. While strength may be optimized, room temperature ductility usually remains at quite low values (<2%). Most useful compositions of lamellar TiAl involve (at least) two phase microstructures of TiAl and Ti3Al. Characterization of deformed samples yields the result that in the main the TiAl lamellae deform readily by twinning and slip, there is little evidence for extensive deformation in lamellae of Ti3Al. This study is aimed at developing an understanding of the deformation behavior in lamellar Ti3Al, focusing on the transmission of slip from adjacent lamellae of TiAl and the factors affecting the activation of dislocations whose Burgers vectors with components perpendicular to the basal plane of this compound (i.e.,[c]-component dislocations). It has been found that transmission of slip as well as stress induced activation of dislocations occurs but that generally motion of [c]-component dislocations is a very difficult. HREM studies have shown that the cores of these dislo- High Resolution Electron Microscopy Electron Resolution High Defect Structures Science: in Materials by: Sponsored Committee Metallurgy Program Organizers: Los Alamos, Group, The Metallurgy MST-6, Laboratory, Allen Crimp, Michigan State NM 87545 USA; Martin of Materials Science and Mechan- Department University, 48824-1226 USA; John E. Smugeresky, ics, East Lansing, MI Department 8724, Livermore, Sandia National Laboratories, CA 94551-0969 USA Tuesday PM March 14, 2000 Session Chair: Los Alamos, NM 87545 and Tech., Matls. Sci. Laboratory, USA 2:00 PM Phase Trans- From Research: of HREM in Materials 25 Years formations to Interface Reactions Stanford, CA 94305-2205 Dept. of Matls. Sci. and Eng., University, USA or so ago, we were demonstrating the applicabil- years Twenty-five resolution, to revealing ity of lattice fringe imaging, at 0.2nm line microscope resolutions details of phase transformation processes. As preparation methods gradually improved and cross-section specimen applied to semicon- became routine, structure imaging was successfully close-packed metals and ductor interfaces and eventually to defects in microscopy (HREM) ceramics. Accordingly high-resolution electron techniques in materi- became one of the most important investigative of studying reactions at als research. Our own work followed the path in situ HREM. Follow- interfaces, including of course development of our current understanding of interfacial ing a brief historical overview, examples of direct con- reactions will be presented, drawing on recent of computer temporary technological importance (e.g. graphitization metallization interfaces hard disk overcoats, amorphization at Ta-Cu etc.). 2:30 PM Invited in Lamellar TiAl HREM Characterization of Slip Transmission Hamish Fraser TH K. G : ∆ ; Morris 1 Shrikant P. Bhat Shrikant P. : Office of Naval Research, Ar- of Naval Research, Office 2 Naval Research Laboratory, Code Laboratory, Naval Research 1 ; 2 Northwestern University, Dept. of Matls. Northwestern University, 2 G threshold is actually increased with mode-mixity, such with mode-mixity, increased is actually G threshold ; A. K. Vasudevan ∆ Ispat Inland Inc., R&D Dept., 3001 E. Columbus Dr., East Dr., Ispat Inland Inc., R&D Dept., 3001 E. Columbus 1 1 ; 2 Sci., 2225 N. Campus Dr., Evanston, IL 60208 USA Evanston, IL Sci., 2225 N. Campus Dr., cracks initiate at the free While it is well recognized that fatigue conducted on carefully surface, most of the mechanistic studies are in most commercial prepared, highly polished specimens. In contrast, oxide layer formed dur- applications that utilize hot rolled steels, the through the in-service ing the manufacture of the steel remains intact research projects, life of the component. Through a series of graduate research program the Inland-Northwestern University cooperative layer of controlled examined the effects of a thermally grown wustite paper, fatigue crack ini- thickness on fatigue crack initiation. In this and modeled. In tiation with and without the wustite layer is compared HSLA steel, the surface both commercially pure iron and an 80 ksi A polished sur- oxide layer drastically changes the crack morphology. extrusions at low strain face results in multitude of intrusions and wustite layer, fewer sur- amplitudes. In contrast, in the presence of a in life, mainly occurring face cracks were seen. They appeared earlier crack formation in this along the grain boundaries. Modeling of the at the interface paper is based on the accumulation of dislocations at a critical dislocation leading to the formation of crack surfaces The influence of grain size and substrate yield strength on density. fatigue crack initiation in the presence of an oxide layer will also be discussed. Chicago, IN 46312 USA; Sadananda USA; DC 20375 6323, Washington, 22217 USA lington, VA the fatigue crack growth has been developed by Unified approach to approach. It is shown that crack growth authors using a two parameter of one in terms of delta K and other in terms involves two thresholds, need to be satisfied simultaneously although Kmax. Both thresholds controlling parameter for a given range of load one or the other is the crack closure is neither necessary or sufficient ratio R. It is shown that crack growth. The anomalous behavior of short to account for fatigue and retardation effects under under-loads cracks and the acceleration successfully accounted using this two param- and overloads have been Kitagawa diagram, it is shown that the con- eter approach. Using the nucleation and growth can be combined to pro- cepts of fatigue crack that is self-consistent and physically mean- vide a unified frame work stressed in crack nucleation, short cracks and ingful. Role of internal the unified approach. overloads are discussed in the frame work of 4:55 PM Initiation in Iron Effects of an Oxide Layer on Fatigue Crack Low Alloy Steel and a High Strength thresholds under mixed-mode conditions. mixed-mode under thresholds 4:30 PM Growth Nucleation and to Fatigue Crack Unified Approach and II, the and II, E. Fine that the mode I value is the worst case. In contrast, preferred crack preferred In contrast, worst case. value is the mode I that the to reduced do lead microstructures lamellar in the coarser paths

TUESDAY PM 95 Two classes ofinterfacialdislocationsplaya roleinthissystem:Dis- dislocations present at I willdiscussourworkonthestructure andbehaviorofinterfacial standing ofsuchdefects.Afterreviewing someofthesekeyadvances, electron microscopy(HRTEM) hassignificantlyimprovedourunder- the atomicscaleinformationprovided byhighresolutiontransmission Though alongstandingissueinmaterials science,overthelastdecade roles indeterminingthestructure andbehaviorofgrainboundaries. Interfacialdefectssuchasdislocationsandstepsplayimportant Sci. Dept.,7011 EastAve., Livermore,CA94551USA L. Medlin Structure andDynamicsofGrainBoundaryDefects 4:20 PM 0208 andF49620-98-1-0321. the AirForceOfficeofScientificResearch,GrantsNo.F49620-98-1- benchmarks fortheabinitiocalculations.Thisworkwassupported by used tocharacterizethedislocationcorestructuresandprovide lated andexperimentallyobtainedHREMimageswillbepresented as inputsforHREMimagesimulations.Directcomparisonsofsimu- provide atomiclevelmodelsofthedislocationcoresthatcanbeused their effects ondislocationmobility. Thetheoreticalpredictions also used topredictdislocationcorespreadingandsplittingderive on the2D-Peierls-Nabarromodelandabinitiocalculationshavebeen planar andnon-planarcoredissociations.Theoreticalanalysisbased surrounding thedislocationcores,allowingforcharacterizationof utilized toexperimentallyobservethearrangementofatomiccolumns fcc Au-Ir,L12Ni3Ge-Fe3GeandL10TiAl-CuAu.HREMhasbeen dislocation corestructuresinthreedifferentsetsofmetalsandalloys: experimental andtheoreticalapproachtocomparecontrastthe mining theirmechanicalbehavior.We haveimplementedacombined large numberofmetalsandalloysplayanimportantroleindeter- Dislocationcorestructurescontrolthemobilityofdislocationsina 620219 Russia 3 Rm. F275,2145No.SheridanRd.,Evanston,IL60208-3112USA; 21218 USA; of Mech.Eng.,122LatrobeHall,3400N.CharlesSt.,Baltimore,MD Gornostyrev tures Based onAbInitioCalculationsofDislocationCoreStruc- Comparisons ofHREMObservationsandTheoreticalAnalysis 3:50 PM 3:30 PMBreak tures. ties ofNiAlandthedeformationgamma-TiAlathighertempera- flow strengthbehaviorobservedinNi be presented.Specificexamplestodiscussedincludetheanomalous vide withrespecttotheuniqueflowpropertiesinthesealloyswillalso tinuum modelingapproaches.Theinsightthatthesecomparisonspro- the directcomparisonofthesefinestructureswithatomisticandcon- gations usinghighresolutionTEMtechniqueswillbedescribed,as roscopic mechanicalproperties.Theresultsofexperimentalinvesti- ing theconnectionbetweenfinestructureofdislocationsandmac- derstanding ofplasticflowinseveralorderedintermetallics,emphasiz- dislocations. Thispresentationwillfocusondevelopmentsinourun- simple metals)whichaffectboththecorestructureanddissociationof linked directlytotheircomplexcrystalstructures(ascomparedwith at hightemperaturesanduniqueflowpropertiesofintermetallicsare high temperatureapplications.Inmanycases,theattractivestrength and scientificinterestduetotheirpotentialasstructuralmaterialsfor Orderedintermetalliccompoundsareofconsiderabletechnological Columbus, OH43221USA University, Matls.Sci.andEng.,477Watts Hall,2041CollegeRd., Intermetallic Compounds Fine StructureofDislocationsandDeformationBehavior 3:00 PM MacDonald asProgramManager. supported bytheNationalScienceFoundation,withDr. Bruce presumably accountsforthelackofmobility. Thisworkhasbeen cations arespreadfairlysignificantlyoutoftheirslipplanesandthis Institute ofMetalPhysics,18S.KovalevskayaSt.,Ekaterinburg : Kevin J.Hemker 1 ; 3 ; ArthurJ.Freeman 1 2 Sandia NationalLaboratories,ThinFilmandInterface Northwestern University, Dept.ofPhys.andAstro., Σ =3 {112}and{111} interfacesinFCCmetals. 1 ; T. JohnBalk : Michael J.Mills 2 ; 1 Johns HopkinsUniversity, Dept. 3 Al, theanisotropicflowproper- 1 ; OlegN.Mryasov 1 ; 1 The OhioState : 2 ; Yuri N. Douglas phous filmsgives directevidenceoftheregular curvature oflattice tion contrast.HREM ofCuSewhiskerswithIBCLP growninamor- characterised byintermediateatom orderingandachangeofdiffrac- focus series)israthersharp,with thetransitionregionabout1nm lized region(analysedindynamics onthephotosmadebythrough- anisotropy. Theinterfacebetween amorphousmaterialandcrystal- served regularitiesareexplainedby combinationofIBCLPandcrystal offset attheboundary, correspondingtotiltingboundaries.Theob- continuously fromonegraintotheotherandwithnoverysharp some oftheplacesexaminedinmoredetaillatticefringesarepassing latter areasnomisfitordislocation-likecontrasthasbeenobserved. In most slowly. Atthegrainboundarieswhicharemostfrequentat orient radiallyinthefilmplane)aremostimperfectandgrowing maximal rates,thecentralareasofevenzones(where[001]tends to film planearehighlyperfectsinglecrystallineareasgrowingwith the nucleus) andthecentralareasofoddzoneswith[001]normalto the tion, imperfectionandgrowthrate[2]:thecrystalcentre(initial alternating circularzonesoftwokindswhichdiffersinlatticeorienta- of amorphousironoxidefilmsisusuallyrealisedbyformation of (0.496 nm)andforTe (0.593nm)differ significantly. Crystallisation rather surprisingfactsincethelatticeconstantsalong[001]for Se same forthesampleswithminimalandmaximalTe content.Itis content inamorphousfilm,whereasmeaninterplanarspacingsarethe of elements(intherange5-20%Te) isbuiltupupontheincreaseofTe growing (0.5-1mm/s)inSe-Te filmswithagradientinconcentration thinner. Themagnitudeofinternalbending incrystalsofhexagonalSe lose thecontrastandbecomelessdiscernibleasfilmgets HREM revealsasteadymeaninterplanarspacingwhilelatticefringes 100¸15 nm)latticebendingisstronglyincreasing.Atthesametime film evaporatedwithastrongthicknessgradient(thicknessrange front movingtothethinnerpartofamorphousantimonyselenide initiate andkeepgoingtheIBCLPphenomenon.Forcrystallisation lattice imperfectionsnorinclusionsofamorphousmaterialwhichcould were alsoused.Themostgeneralresult:HREMdisplayedneitherany internal latticebendingandcrystalthickness.EDX,EELSCBED lattice orientation(incombinationwithselectedareadiffraction), Micrograph software.Bendcontourtechniquewasusedtoevaluate CM200FEG andaslowscanCCDcameraanalyzedwiththeDigital situ. HREMwasperformedinaplaneviewofthesampleswith tion wasusuallyinitiatedbyelectronbeaminsideTEMandtracedin tion andlatticeorientationontheIBCLPphenomenon.Crystalliza- structures, demonstratingtheinfluenceoffilmthickness,composi- axis lyinginthefilmplane).InthispaperwepresentHREMofsome crystal latticeplanes(IBCLP)inagrowing(realizedaroundan crystal length)regular,dislocationindependentinternalbendingofthe This newphenomenonresidesinstrong(upto120 formation wererevealedearlierbyTEMstudiesinsomethinfilms[1]. Unusualmicrostructuresformedduringamorphous-crystallinetrans- Phys., Göteborg41296Sweden 620219 Russia; nomic University, Eng.Dept.,8-thMarch62,GSP-985,Ekaterinburg in ThinFilms Formed asaResultofAmorphous-CrystallineTransformations HREM ofCrystalswithUnusualInternalLatticeBending 4:50 PM Division ofMaterialsScience,undercontractDE-AC04-94AL85000. Department ofEnergy, in partbytheOffice ofBasicEnergy Sciences, interpreting theobservations.ThisworkissupportedbyU.S. calculations andtheresultingprovidinginsightcriticalto vations ofdefectconfigurationsmotivatingatomisticandcontinuum coupling betweencomputationandexperiment,withHRTEM obser- terfacial dissociation.Throughout,Iemphasizethenecessarilyclose (2) shearprocessesofa/6<112>dislocationsandtheirimpactonin- 3<111> dislocationsleadingtointerfacialslidingandtwingrowth concentrate ontwoexamples:(1)glideandclimbprocessesofa/ dicted fromtheinterfacialdislocationstructure.Inparticular,Iwill rich varietyofphenomenathatcanbedirectlyunderstoodandpre- decomposition reactions.Eventhisrelativelysimplesystemyieldsa deviations fromideallatticecoincidenceorthroughdislocation 3<111>. Suchdislocationsoriginateasameansofaccommodating locations withBurgersvectora/6<112>anda/ : 2 Vladimir Kolosov Chalmers UniversityofTechnology, Dept.ofExp. 1 ; A.R.Thölén 2 ; 1 Ural StateEco- ° per 1mmof

TUESDAY PM 96 ; 1 University of University of 1 1 ; ; 1 1 ; Christopher Schuh 1 General Motors, Rsrch. and Motors, General 1 Hsu-Yang Technologies Com- Technologies Hsu-Yang ; 1 1 ; 1 Matra Defense, STTN, 20-22 Rue David L. Bourell 2 James C. Earthman : C (in the beta-field of titanium), and ° : David C. Dunand : Shu-En Hsu : Paul E. Krajewski Paul E. Northwestern University, Dept. of Matls. Sci. and Dept. of Matls. Sci. Northwestern University, 1 : ; 2 C (about the alpha-beta phase transformation of titanium). In ° Abstract text is not available Philippe A. Noel Taiwan Taipei-Hsian, pany Limited, 80 Erh-Chia Rd., Ying-Keh, pioneering In response to the influence of Prof. Oleg D. Sherby’s contributions to the field of high-temperature mechanical behavior, strain-rate effects and creep behavior of NiAl and TiNi intermetallics have been investigated. NiAl intermetallics were once recognized as Eng., Evanston, IL 60208 USA; 78141 France Grange Dame Rose, Velizy The densification of titanium powders is investigated in uniaxial die pressing experiments at 980 compared with densification during thermal cycling between 860 and 980 and Sherby on agreement with the 1982 paper by Ruano, Wadsworth white cast iron powders, we observe that thermal cycling enhances densification kinetics of titanium powders through the emergence of transformation-mismatch plasticity (the mechanism responsible for transformation superplasticity) as a densification mechanism. The isothermal hot-pressing data compare favorably with existing models of powder densification, and these models are successfully adapted to the case of transformation-mismatch plasticity during thermal cycling. 4:20 PM Invited Strain Rate Sensitivity and Creep Behavior of Some Nickel- Based Intermetallic 2:40 PM 2:40 of Behavior on the Creep Reinforcement of Particle The Effect Alloys Aluminum USA MI 48090 Warren, 30500 Mound, MC-480-106-212, Ctr., Dev. of alu- on the creep behavior of particle reinforcement The effect strengthening direct and indirect will be reviewed. The minum alloys solid solution examined in pure, reinforcement are effects of particle In pure aluminum alloys. and precipitation strengthened strengthened, substruc- controlled by dislocation where strengthening is aluminum, In behavior. controls creep composite strengthening ture, indirect alloys, where a dislocation substructure solid solution strengthened strengthening dominates creep behavior and does not develop, direct in pre- by continuum models. Finally, strengthening can be predicted alloys, indirect strengthening dominates creep cipitation strengthened reinforcements on precipitate of the particle The effect behavior. of can actually lead to composite weakening distribution and stability creep deformation. Ideas for designing a creep aluminum alloys during will be suggested. resistant aluminum composite 3:00 PM Invited 7075-T6 Al at Ambient and Behavior of Open Cellular Tensile Intermediate Temperatures CA of Chem. Eng. and Matls. Sci., Irvine, California, Irvine, Dept. 92697-2575 USA 3:20 PM Break 3:40 PM Invited in Selective La- Powder Densification Maps and Applications ser Sintering Post Processing Matls. Instit., Mech. Eng., MC C22000, Aus- at Austin, Texas Texas tin, TX 78712 USA Freeform Fabrication pro- Selective Laser Sintering (SLS) is a Solid without the use of cess in which a part is built quickly from powders ceramic and composite part-specific tooling. Production of metallic, sintering to achieve parts often requires some form of post-process Densification Maps represent a potent tool for Powder full density. achieve full density parts. optimizing the post-processing parameters to of part density as af- Such maps are computational representations properties. Criti- fected by time, temperature, pressure and materials is an understanding of cal to the formulation of densification maps will summarize SLS de- This presentation time-dependent plasticity. at Austin with emphasis on velopments at The University of Texas of part post-processing. the utility of powder densification mapping 4:00 PM Invited Powders by Cyclic Trans- Enhanced Densification of Titanium formations under Stress Brian : Kochi University of 1 ; 1 Yoshio Monma Yoshio : Eric M. Taleff, University of Texas, Eric M. Taleff, Room: Bayou E Location: Opryland Convention Center David Bourell, The University of Texas, TX David Bourell, The University of Texas, Structural Materials Division, Materials Structural Materials University of Wales Swansea, Matls. Eng., Singleton Park, University of Wales 1 ; 1 Technology, Dept. of Environ. Sys. Eng., Tosayamada-cho, Kami- Sys. Eng., Tosayamada-cho, Dept. of Environ. Technology, gun, Kochi 782-8502 Japan Parameter) methods pro- Among various TTP (Time-Temperature posed for the extrapolation of creep-rupture data, the merit of OSD (Orr-Sherby-Dorn) and BAS (Barrett-Ardell-Sherby) parametric procedures are not recognized widely as compared with the LM (Larson- Miller). Because of the availability of the long-term stress rupture data from the NRIM Creep Data Sheet program, which includes many data points beyond 100,000h for various heat-resisting steels and alloys, we can directly validate the ability of fitting and extrapolation by TTP methods. This paper is to examine the accuracy of extrapolation OSD and BAS methods using computerized data evaluation system. We consider the treatment of the heat-to-heat variation, how to incorporate the microstructural changes during long-time creep in TTP analysis. Wilshire Swansea, Wales SA28PP UK Swansea, Wales of oxide-dispersion- It has recently been shown that, during creep of the dispersoid par- strengthened (ODS) alloys, the principal role present after ticles is to stabilize the retained dislocation substructures creep resistance of ODS thermo-mechanical processing. Linking the defines three catego- alloys to their retained dislocation densities then on grain size and shape. ries of stress/creep rate behaviour, depending with equiaxed grain (i) Category A characteristics are found for alloys (ii) Category B structures and low retained dislocation densities. high grain-aspect-ra- behaviour is observed with polycrystals having high retained dislocation tios (GAR), relatively fine grain sizes and by ODS single crys- densities. (iii) Category C properties are displayed both having high tals and by coarse grain high-GAR polycrystals, retained dislocation densities. The validity of this classification system is illustrated by reference to the high-temperature creep properties recorded for three types of ODS ferritic steel. 2:20 PM Invited Critical Assessment of Creep Extrapolation Using OSD and BAS Parameter Methods 2:00 PM Invited Ferritic Steels Creep of Oxide-Dispersion-Strengthened Tuesday PM Sponsored by: Department, Austin, TX 78712- Mechanical Engineering Lawrence Livermore National Lesuer, 1063 USA; Donald R. CA 94550 USA; Chol K. Syn, Livermore, Laboratory, & Manufacturing National Laboratory, Lawrence Livermore Division, Livermore, CA 94550 USA Materials Engineering March 14, 2000 Session Chair: Matls. Instit., Austin, TX 78712-1063 USA Honorary Symposium for Professor Symposium Honorary Creep Mechanisms Oleg D. Sherby: B and Behavior Division, Structural Materi- Processing and Manufacturing and Forming Committee als Committee, Shaping Organizers: Program planes. References: 1. Kolosov V. Yu., Proc. XII ICEM, Seattle, San Seattle, ICEM, XII Proc. Yu., V. 1. Kolosov References: planes. A.R., And Thölén Yu. Kolosov V. (1990). 2. 1, 574 Press, v. Francisco RSAS support of Partial 9, 323 (1997). Materials, NanoStructured acknowl- is gratefully 97-02-17784) RFBR (grant 1557) and (grant edged.

TUESDAY PM 97 stoichiometry oncreepbehaviorcouldbeexplained. Ni taking theeffectofAlconcentrationoninter-diffusioncoefficient of from onestotheothersgovernsvelocityofdislocations. By vacancy sinkfortheclimbmotion.Thetimemigration of jogs,onewhichactsasavacancysourceandtheother a ture range.Thedouble-kinktypelockingpartsarecomposedofapair mechanism controlledbydiffusivityofvacancyinthehightempera- kink typeconfigurationcanbeexpectedtomovewithadragging mechanism, asabasis.Thiscross-slippedpartswhichhavedouble- of screwdislocation,well-knownastheKearandWilsdorf(K-W) to explainthestressanomalywithformationofcross-slippedpart such hightemperatures.Largenumberofstudieshavebeenattempted stress anomalypersistsinitseffectonthedislocationmotionevenat higher thanthepeaktemperature,andmechanismcontrolling (111) planegovernsthecreepdeformationofNi slip. We haverevealedthattheviscousmotionofdislocationson intermediate temperaturesaswellfortheathermalstressofcube ent activationenergyforthestressanomalyofoctahedralslipat strength. Thesingularityhadpreviouslybeenobservedfortheappar- have showntheexistenceofsingularityatstoichiometryforcreep Systematicinvestigationsonbothpoly-andsingle-crystallineNi Yokohama 226-8502Japan nology, Dept.ofMatls.Sci.andEng.,4259Nagatsuta,Midori-ku, Tosayamada-cho, Kochi782-8520Japan; 8628 Japan; Div. ofMatls.Sci.andEng.,Kita-13 Nishi-8,Kita-ku,Sapporo060- Miura Singularity ofCreepStrengthinNi 4:40 PMInvited ing goodswillbepresentedinthisreport. lustrations ofapplicationsforTiNi-basedintermetallicsusedinsport- technologically significantformanufacturingengineering.Severalil- presence ofthisdualbehaviorsuper-elasticityandsuperplasticityis the dampingcapacitywashighsincemodulusverylow. The exhibited superplasticityathightemperature,wellaboveAf,where martensitic transformation.Alternatively, Cu-modifiedTiNi-SMA tic (Super-elastic)materialcanbeobtainedbypropercontrolofthe tensitic transformationatlowtemperature,belowMs.Apseudo-elas- modulus decreased.Moduluschangewasduetothestressinducedmar- found thatthecoefficientofstrain-ratesensitivityincreasedaselastic the strain-ratesensitivityofCuandV-ComodifiedTiNi-SMA.Itwas tion amongthemodernadvancedmaterials.Thisreportwillreview the samematerialatdifferenttemperatureswillattractmoreatten- formation, theco-existenceofsuperplasticityandsuper-elasticityin memory, highdamping,andpseudo-elasticityduetomartensitictrans- tional inherentductility. Besidestheinterestingphenomenaofshape hand, unlikemostofthestructuralintermetallics,TiNihasexcep- components inaero-enginesatelevatedtemperature.Ontheother shortness oftheseintermetallicspreventedtheirapplicationtocrucial nisms thatcanbeappliedtoovercomestrain-ratesensitivity, thehot- TiAl orFeAl.Asaresult,exceptforsomeeffectivetougheningmecha- was acommontrendformanyotherstructuralintermetallics,suchas sensitivity resultedinreductionofductilityandtoughness.Infact,this significantly. However, adecreaseofthecoefficient ofstrain-rate both thestressexponentandactivationenergyforcreepincrease and single-crystalNiAl-intermetallics.Experimentalresultsshowthat report reviewstheresultsofstrain-ratestudypolycrystalline was notsosuccessfulwhenstrain-ratesensitivityevaluated.This evated temperature.However, aftermanyyearsofstudy, theoutcome ideal aerospacematerialsforkeycomponentsinturbo-enginesatel- 3 Al, boththesingularityatstoichiometryandeffectofoff- 1 ; Yoshinao Mishima 1 Kochi UniversityofTechnology, FacultyofTech., 2 ; Tomoo Suzuki 3 Al atStoichiometry 2 1 Tokyo InstituteofTech- ; 1 Hokkaido University, 3 Al attemperatures : Seiji 3 Al and Oxidation on ParallelComputers-SinteringandConsolidation,Fracture, Multimillion AtomSimulationsofNanostructuredMaterials 2:00 PMInvited Eng., UniversityPark,PA 16802USA Long-Qing Chen,PennStateUniversity, Matls.Sci.and Technology, Matls.Sci.andEng.,Nagoya466-8555Japan; Session Chairs: Room:JohnsonA/B March 14,2000 PM Tuesday CA 94551-0808USA Gonis, LawrenceLivermoreNationalLaboratory, Livermore, Technology Division,Livermore,CA94551USA;Antonios Livermore NationalLaboratory, MaterialsScienceand Program Organizers: Committee Magnetic &PhotonicMaterialsDivision,AlloyPhases Sponsored by: in Materials:SessionIII Phase Transformations andEvolution Hume RotheryAward Symposium; is ofconsiderable interestbecauseitlendstheability totailormaterial Dimensionallyinducedphasetransitions inthinfilmsandmultilayers 43210 USA Matls. Sci.andEng.,477Watts Hall,2041CollegeRd.,Columbus,OH Rajarshi Banerjee Phase Transitions inMetallicMultilayers 3:00 PMInvited different twingeometriesareexamined. understanding ofdefectenergetics.Forcompleteness,anumber of twinned systemintermsofidealizeddefects,leadingtoanintuitive analytical resultsarecomplementedbysimplifieddescriptionsof the ing electrostaticandelasticdefectswithinaunifiedframework.Our multipole characteroftheimperfectionsassociatedwithatwin,treat- of athinferroelectricfilm.Theanalysisemployedfocuseson the We examineelectrostaticandelasticcontributionstothetwinning University, Matls.Sci.&Eng.,Bethlehem,PA 18015USA 2 Instit., BowenHall,70ProspectAve., Princeton,NJ08540USA; N. Sridhar A DefectModelforTwinning inFerroelectrics 2:30 PMInvited and PRF. AFOSR, ARO,USC-LSUMURI(DARPA &AFOSR),AustrianFWF, temperature distributions.ResearchsupportedbytheUSDOE,NSF, at elevatedtemperaturewillbereportedalongwithlocalstressand nanoclusters andnanoindentationsimulationatroomtemperature interface. Multimillionatomsimulationsofoxidationaluminum ceramic interfaceisstudiedbyapplyingtensilestrainparalleltothe fracture surfacesisexamined.Mechanicalfailureatsemiconductor/ Crack propagationandfracturearestudiedthemorphologyof are usedtovalidatetheinteratomicpotentialsinsimulations. Structural correlationsdeterminedbyneutronscatteringexperiments ure incrystallineceramics,nanophaseandatinterfaces. million atomsimulationshasbeenusedtoinvestigatemechanicalfail- Multiresolutionmolecular-dynamics(MRMD)approachformulti- Baton Rouge,LA70803-4001USA current Comp.Lab.forMatls.Sims.,Depts.ofPhys.andSci., Aiichiro Nakano thy Campbell Rockwell ScienceCenter,ThousandOaks,CA91360USA; 2 ; Jeffrey Rickman 1 ; RajivK.Kalia : 1 ; PhillipWalsh Structural MaterialsDivision,Electronic, 1 Priya Vashishta ; SulimanA.Dregia Toru Miyazaki,NagoyaInstituteof Location: OprylandConventionCenter Patrice E.A.Turchi,Lawrence 3 ; 1 ; HideakiKikuchi 1 Princeton University, PrincetonMatls. 1 ; 1 ; MartinaE.Bachlechner 1 Louisiana StateUniversity, Con- 1 ; 1 The OhioStateUniversity, : 1 : ; SanjayKodiyalam Hamish L.Fraser David J.Srolovitz 1 ; Timo-; 3 Lehigh 1 1 1 ; ; ;

TUESDAY PM 98 ; Mark Sandia 2 1 ; ; Amit K. 1 1 Stanford University, ; Drew Nelson 2 1 University of Michigan, 1 ; 1 ; Michael Oliver 1 Debasisch Dutta : anal E Michelle Griffith : David L. Bourell, University of Texas, David L. Bourell, University ; Jyoti Mazumder ; Donald Greene 1 Location: Opryland Convention Center 1 Iver E. Anderson, Iowa State University, Materials Processing and Manufacturing Materials Processing ; Noboru Kikuchi 2 ; Daryl Reckaway 1 University of Michigan, Dept. of Matl. Sci. and Eng., Ann Arbor, MI University of Michigan, Dept. of Matl. Sci. and Ensz Dept. of Mech. Eng. and Appl. Mech., Ann Arbor, MI 48109 USA; Dept. of Mech. Eng. and Appl. Mech., Ann Albuquerque, NM USA; National Laboratory, 2:00 PM Fabrication of Designed Materials 2 48109 USA and fabri- describe a new technology for design, representation, We It involves the computer cation of graded materials; and components. homogenization design integration of three core technologies, that of material deposition. method, heterogeneous solid modeling, and direct system framework and describe each core tech- show the overall We nique in detail. Examples of design and fabrication of a materials system with desired properties using proposed methodology are presented in the paper. 2:30 PM The Development of Residual Stress in Laser Engineered Net Shaping (LENS) Fabrication Stanford, CA USA In direct laser metal deposition technologies, such as the LENS process, it is important to understand and control the emergence of residual stresses during fabrication. In essence, the thermal behavior and its transients during fabrication must be monitored and, hopefully, controlled to reduce residual stresses to usable levels. This talk will describe techniques to monitor the thermal signature and history during LENS processing. Methods to measure the residual stress in LENS components will be described, and correlation between thermal his- microstructural evolution, and resulting stresses will be discussed. tory, Development of an understanding of residual stress manifestation and ways to reduce residual stress will be discussed. tural intermediate states realized by a dilation-adjustment mechanism dilation-adjustment by a states realized tural intermediate author. by the present proposed recently on Global Symposium International Processing in Materials Innovations Direct Fabrication and Manufacturing: and Metal Powders Sponsored by: Division, Organizers: Program Department, Austin, TX 78712- Mechanical Engineering Ames Iowa State University, 1063 USA; Iver Anderson, Sears, USA; James W. Ames, IA 50011-3020 Laboratory, NY Schenectedy, Inc., D2, 114, Lockheed Martin, KAPL Sandia National Laborato- Smugeresky, 12301 USA; John E. Livermore, CA 94551-0969 USA; Dan ries, Department 8724, Materials National Laboratory, J. Thoma, Los Alamos USA; Los Alamos, NM 87545-0001 Science and Technology, Oak Oak Ridge National Laboratory, Srinath Viswanathan, The Ohio State Ridge, TN 37831-6083 USA; Rob Wagoner, of Materials Science and Engineer- Department University, ing, Columbus, OH 43210 USA Tuesday PMMarch 14, 2000 C Room: Session Chair: Ames National Lab., Ames, IA 50011 USA Ghosh : K. Akira : University of Maryland, Northwestern University, 1 1 ; ; 1 1 P. W. Voorhees W. P. ; 2 Alexander L. Roytburd : Kyoto University, Dept. of Phys., Kyoto 606-01 Japan Kyoto University, ; N. Akaiwa 1 1 National Research Institute for Metals, 1-2-1 Sengen, Tsukuba National Research Institute for Metals, 1-2-1 ; 2 1 I will discuss effects of elastic misfit interactions in phase separation and structural phase transitions and present some new computational results in 2D and 3D. I am particularly interested in (i) slowing down of phase separation at high volume fractions with elastic misfit, (ii) critical behavior of binary solids influenced by elastic misfit (where even thermal fluctuations can be elastically affected), and (iii) struc- Matls. Sci. and Eng., 2225 N. Campus Dr., Evanston, IL 60208-3108 Matls. Sci. and Eng., 2225 N. Campus Dr., USA; 305-0047 Japan evolution of micro- A major challenge in predicting the late-stage in lattice param- structures in two-phase solids is that the difference engenders a long-ranged eters between the particle and matrix phases where the evolution of elastic stress field. Unlike stress-free systems, the total interfacial en- the microstructure is driven by a decrease in in these materials ergy of the two-phase mixture, the ripening process is driven by a decrease in the sum of the elastic and interfacial energies. It is thus not clear if the classical results of interfacial energy driven ripening hold true in elastically stressed solids. Due to the strong shape dependence of the interparticle elastic interactions this issue can only be addressed using large-scale numerical calculations. Through the use of boundary integrals and the fast multipole method, we have examined the morphological evolution of many thousands of elastically and shall discuss the temporal evo- interacting particles. We diffusionally lution of the statistically averaged properties of these coarsening en- sembles, such as the exponent of the temporal power law for the average particle size, the dependence of the rate constant on volume fraction, and the evolution of the spatial correlations between particles. 4:45 PM Invited in Solids Elastic Misfit Interactions at Phase Transitions Matls. and Nuc. Eng., College Park, MD 20742 USA Matls. and Nuc. Eng., College Park, MD 20742 is discussed. Thermodynamics of constrained phase transformations of polydomain The concept of elastic domains is used for description 1D- constraint. As ex- microstructures formed under 3D-, 2D- and and epitaxial films are amples phase transformations in composites phase transformations. discussed, as well as self-constrained coherent conditions is demon- Dependence of phase diagrams on constraint strated. 4:15 PM Invited Stressed Solids Late-Stage Phase Separation in Elastically Thornton Onuki properties by engineering their structure at the nanoscale. Recently, a Recently, at the nanoscale. structure their by engineering properties in Ti/Al reported have been transitions phase of interesting series to hcp structure its bulk stable from Ti transforms wherein multilayers and Al transforms (~ 5nm) thicknesses small layer structure at an fcc were reported structural transitions hcp at ~ 2.5 nm. These from fcc to on sputter (TEM) studies electron microscopy based on transmission cross-section thinned in the multilayered specimens deposited Ti/Al model has been a classical thermodynamic Subsequently, geometry. materials as a in multilayered explaining phase stability proposed for this model it thickness. Using the composition and bilayer function of on the effect of cross-section thinning has been possible to rationalize of the anisotropic ingress of hydrogen into the phase stability in terms for The model presents an elegant framework the Ti/Al multilayers. of alloying/impurity additions on the phase rationalizing the effect by con- the scope of model has been expanded Furthermore, stability. to other systems including non close-packed sidering its applicability in Recent experiments have explored ones such as Co/Cr multilayers. fcc Ti and the coherent to incoherent transi- detail the formation of as a function of composition and bilayer tion in Ti/Al multilayers the initial thermodynamic model has been modi- thickness. In addition, effect of coherency strains on the phase stabil- fied to account for the in detail and a new phase stability These results will be discussed ity. for Ti/Al multilayers. diagram will be proposed 3:30 PM Break 3:45 PM Invited and Mi- Thermodynamics Constrained Phase Transformations: crostructure

TUESDAY PM 99 Analysis resultsand actualmoldtestdatawillbepresented comparing tortion, anddramatically increasedmoldproductivity. FiniteElement and cooling,quasi-isothermalactive moldsurfaces,reducedpartdis- management layers,conformalcooling channels,sequentialheating conductivity moldmaterials,nickel activesurfaces,copperthermal tant moldcharacteristics:lowthermal inertiainserts,highthermal information willbepresentedregarding eachofthefollowingimpor- vanced plasticinjectionmolddesign andconstruction.Specifically, Thispresentationwilldiscusssomerecentdevelopmentsin ad- press Tool, Warwick, RI USA Advanced MoldDesignandConstruction 4:20 PM cussed. these fieldsandinothercloselylinkedareasofresearchwillbedis- that theapproachwhichisbeingusedhaspromiseandprogress in tool steelsfordifferentapplications.Preliminaryworkhassuggested which aimstoproducelong-life,fullydensetoolingforanumber of now underwayaimedatproducingtoolingbybothofthesetechniques direct laserfabricationfacilitywitha1.4kWlaser. Programmesare the equipmentisasinterstationwithlaserupgradedto100Wand a laboratory fittedoutwithover£3.5Mofprocessingequipment.Among the areaofNetShapeManufacturingwithrecentopeninganew TheInterdisciplinaryResearchCentre(IRC)hasamajoractivityin Birmingham, Interdis.Rsch.Ctr., EdgbastonB152TTUK Sercombe by RapidPrototyping andbyDirect LaserFabrication Materials Research intheIRCRelevanttoTooling Produced 3:50 PM 3:30 PMBreak tionality. composite (reinforced)microstructuresandSMART componentfunc- components withnovelfeaturessuchasvariablecompositionlayers, two approachescanbeutilizedintheproductionofnearnetshape these developmentsandtosuggesthowthebringingtogetherof during thebuildprocedure.Theobjectiveofthispaperistoreview tor thatmaintainsanullpointbeneaththestationarylaseratalltimes (Laser DirectCasting).Thisisdoneusingauniquesix-axismanipula- cladding processtotheincrementaladditionbuildingofcomponents of componentsfromCADdatacanbeachievedbyadaptingthelaser this means.Atthesametime,ithasbeenshownthatlaserdirectbuild crostructural variationintertiaryalloysystemscanbeachievedby puter control.Ithasbeenfoundthatcompositionalcontrolandmi- Liverpool byemployingamultiplepowderhoppersystemundercom- Variable compositionlasercladdinghasbeendemonstratedat L693BX UK Liverpool, Dept.ofEng.,LaserEng.Grp.,BrownlowSt.,Liverpool Laser Direct Casting Variable CompositionLaser CladdingandItsApplicationin 3:10 PM DE-AC04-94AL85000. Work supported bytheU.S.DepartmentofEnergy undercontract refinement anddislocationdensityaffectthemechanicalproperties. of ourmicrostructureanalysiswillbediscussedtoshowhowbothgrain strength ofannealedmaterialthereisnolossinductility. Theresults annealed materialwithlittlechangeinductility. Atdoubletheyield strengths betweentwotothreetimesthatofconventionallyprocessed the processconditions,itispossibletoobtainarangeoftensileyield dependent onprocessparametersandcomposition.Byvaryingonly carbide particles,havebeenengineeredtoobtainarangeofproperties microstructures. Samplesof316SSwith,andwithoutfinetungsten metal shapeswithmonolithic,composite,andfunctionallygraded evaluated theprocessparameterspaceformakingusefulfullydense UsingtheLaserEngineeredNetShaping(LENS que, NMUSA; pany, Albuquerque,NMUSA; Laboratory, Livermore,CA94551-0969USA; Philliber Composite Materials Engineering theMicrostructureandPropertiesin316SS 2:50 PM 1 ; J.AnthonyRomero 1 ; X.Wu 4 Vanderbilt University, Nashville,TNUSA 1 ; I.T.H. Chang : : Ken Watkins John E.Smugeresky 3 3 W. ; H.Hofmeister Sandia NationalLaboratory, Albuquer- 1 ; 1 ; MattMurphy M. H.Loretto : 1 ; D.M.Keicher 2 Paul F. Jacobs Optomec DesignCom-  4 ; ) process,wehave 1 1 ; 1 ; Sandia National 1 1 University of University of 1 2 ; ; J.A. : T. 1 Ex- LENS aimed atassessingtheviabilityofuseelementalpowdersduring solution istheuseofelementalblendspowders.Thepresentstudy when thealloyingelementsarereactive,forexampleTi.Anobvious being thecostinvolvedinprocuringpre-alloyedpowders,particularly there aresomepotentialbarrierstoitswidespreadapplication,one to post-consolidateparticulateandnet-shapeprocessing.Incontrast, of LENS Therearesomeveryexcitingpossibilitiesaffordedbyapplication Sci. andEng.,2041CollegeRd.,Columbus,OH43210USA Amancherla Alloys UsingLens Use ofElementalPowderBlendsintheFormationComplex 4:40 PM nickel-copper electroformed/steelbackedtools. the performanceofconventionalsteeltoolswithnew, advanced ergy underContractDE-AC04-94AL85000. Lockheed MartinCompany, fortheUnitedStatesDepartmentofEn- Sandia isamultiprogramlaboratoryoperatedbyCorporation, parameters andtheresultantmicrostructureswillalsobediscussed. surements fortheH13alloy. Therelationshipsbetweenprocessing scriptions ofthevariousprocessescoupledwithexperimentalmea- subcritical peaktemperatures.Themodelsarebasedonclassicalde- and carbidecoarseningmodelstoaccountforthermalcycleswith models toaccountforreheatingintercriticalpeaktemperatures, developed. Theseincludesolidificationmodels,phasetransformation of microstructureinH13toolsteelduringthevariouscyclesarebeing perature thermalcycles.Inthecurrentwork,modelsforevolution These historiesincluderemeltingaswellnumerouslowerpeaktem- plex thermalhistoriesareexperiencedindifferentregionsofthebuild. layer. Theprocessistherebysimilartomulti-passwelding,andcom- Fabrication proceedsbybuildingthestructurelineandlayer cated bycreatingalasermeltedpoolintowhichparticlesareinjected. IntheLaserEngineeredNetShape(LENS)process,partsarefabri- USA; M. L.Griffith Steel Microstructural EvolutionDuringLENSFabricationofH13Tool 5:00 PM presented anddiscussed. taken fromtheTiAl,Mo-Si-BandNb-Nbsilicidesystemswillbe and Ti-Nb. Finally, theresultsofprocessingcomplexalloys have beenundertakeninvolvingtheuseofelementalblendsTi-Cr control experiments,aimedatassessingtheinfluenceofthisfactor, influencing theuseofelementalpowdersisheatmixing.Some processed materialisratherhomogeneous.Amongthevariousfactors cessed sampleshavebeendeterminedandithasshownthatthe phase materialresults.Thecompositionalvariationsovertheas-pro- have beenprocessedandithasshownthatrapidlycooled,single of NiandMopowderscorrespondingtothestoichiometry : TM 2 Sandia NationalLaboratory, Livermore,CA87185USA C. V. Robino processing.Aspartoftheinitialassessment,elementalblends TM technologyincludingrapidsolidificationwithouttheneed 1 ; RajarshiBanerjee 1 ; 1 Sandia NationalLaboratory, Albuquerque, NM87185 TM 1 ; R.C.Dykhuizen : Hamish L.Fraser 1 ; 1 The OhioStateUniversity, Matls. 1 ; J.A.Brooks 1 ; KatrinSchwendner 2 ; T. J.Headley 1 ; Sundar 3 Mo 1 ;

TUESDAY PM 100 ; ; 1 1 ; I. 1 H. Hosoda University of A. Smirnov P. J. Hill P. atmosphere. 2 2 : : : Mintek, Phys. Metallu. 1 ; 3 formed above Ir layer. A problem formed above Ir layer. 3 O Tohoku University, Instit. for Matls. University, Tohoku 2 2 University of Tsukuba, Instit. for Matls. Instit. University of Tsukuba, 1 ; M. J. Witcomb ; 2 2 C. Thermogravimetric testing under air and ° University of the Witwatersrand, Elect. Micro. 3 C. Current work seeks to elucidate the effect of work seeks to elucidate C. Current ° . Ir plays a role of ODB and formation of iridium oxides . Ir plays a role of ODB and formation of iridium 3 ) is suppressed by Al ; S. Hanada 3 2 O 2 ; L. A. Cornish 1 and IrO 2 Engelhard-Clal L.P., 700 Blair Rd., Carteret, NJ 07008 USA 700 Engelhard-Clal L.P., techniques such as X-ray diffraction and metallography have been used to assess the oxidation behaviour of these alloys, allowing optimal alloy compositions to be selected. 3:20 PM Mutual Diffusion in Couple of Iridium-Rhenium 1 Bimetal composition of a rhenium and iridium has provided high- temperature capability for usage in different applications-rocket nozzles or crucibles for crystals growth. The use of different materials at high- Div., Private Bag X3015, Randburg 2125 South Africa; Private Bag X3015, Randburg Div., Unit, Private Bag 3, Wits 2050 South Africa requiring good high- Alloys for application as spark-plug electrodes, resistance at elevated temperature strength and exceptional oxidation work has shown that temperatures, are being investigated. Previous alloys based on IrAl have exceptionally high hardnesses, and oxidation properties comparable with those of RuAl-based alloys. Additionally, some Ir-based alloys are known for their superior high-temperature mechanical properties. An isostructural B2 phase has been found to form between IrAl and RuAl, allowing substitution between Ir and Ru. Convergence between the room temperature toughness of RuAl, and the superior high-temperature mechanical and oxidation properties of IrAl is being sought. Although a thorough assessment of the oxidation, cyclic oxidation and hot corrosion behaviour of the alloys is required, an initial indication of the alloys’ properties can be obtained from isothermal oxidation testing. This paper is concerned with the isothermal oxidation behaviour of IrxRu50-xAl50 alloys in the temperature range 900 to 1400 S. Watanabe 305-8577 Japan; Rsch., Tsukuba Japan Rsch., Sendai 980-8577 of B2 IrAl alloys containing Ni was investi- Oxidation behavior potential to be ultrahigh-temperature oxygen- gated. IrAl has large due to formation of smart structure composed diffusion-barrier (ODB) of Ir and Al (IrO oxidation easily occurs at of IrAl fabricated by ingot metallurgy is that are usually intro- boundaries between IrAl and Ir domains: Ir domains by a powder metallur- duced through solidification. This may be solved and Ni addition stability, gical method and improvement of B2 phase IrAl. Alloys containing was expected to improve phase stability of B2 pressing method using 51 mol % Al were fabricated by a reactive hot were carried out under high-purity elemental powders. Oxidation tests K/min up to 1863 K and the conditions of (1) continuous heating of 10 K in an O (2) isotherms between 1273 K and 1863 thermogravimetry Oxidation behavior was studied by simultaneous and SEM observation. It thermal analysis (DTA) (TG)- differential oxidation resistance was found that Ni addition dramatically improves is also discussed. of IrAl. Effect of Ni addition on mechanical property 3:00 PM Oxidation of Alloys Based on B2 IrxRu50-xA150 M. Wolff Eng., Private Bag 3, Wits the Witwatersrand, Schl. of Proc. and Matls. 2050 South Africa; points, and exceptional mechanical properties. The well-known ‘bo- well-known The properties. mechanical and exceptional points, and both strength to improve found has been effect’ ron ductlising as 0.5 at of as little additions However, systems. in the above ductility com- RuAl based of the resistance the oxidation modify % boron temperatures oxidation rates at to escalated internal pounds, leading 1300 approaching and Ir-Nb resistance of the Ir-Al on the oxidation boron additions oxidation and static isothermal analyses systems. Thermogravimetric oxidation the operative have been used to characterise techniques behaviour of between the which leads to a comparison mechanisms, ex- alloys. The companion paper the ruthenium- and iridium-based between the singular room temperature tough- plores the convergence and the superior strength and oxidation resis- ness in the RuAl system in the RuxIr50-xAl50 series. tance in the IrAl system 2:40 PM of IrAl Alloys Containing Ni Oxidation Behavior ; 1 ; J. 1 Mintek, Phys. 1 ; E. P. George ; E. P. ; E. H. Lee 1 1 ; 1 ; P. J. Hill ; P. Dentsply International, Pre- 1 Th precipitates in the matrix 3 ; L. Heatherly 5 1 C. G. McKamey Byron Products Inc., 3781 Port Th precipitates and diffusion of is thermodynamically favorable, 2 5 2 : I. M. Wolff : ; J. L. Wright Evan K. Ohriner, Oak Ridge National Oak Evan K. Ohriner, 3 Location: Opryland Convention Center Location: Opryland Peter Panfilov, Urals State University, Peter Panfilov, Structural Materials Division, Refractory Materials Division, Structural Nb (L12), and RuAl (B2), which have high melting 3 ; A. N. Gubbi 2 C for times up to 3000 h. The results show the presence of C for times up to 3000 h. The results show ° Oak Ridge National Laboratory, Mets. and Cer. Div., P.O. Box 2008, P.O. Div., Mets. and Cer. Oak Ridge National Laboratory, Metallu. Div., Private Bag X3015, Randburg 2125 South Africa Private Bag X3015, Randburg Metallu. Div., Intermetallic compounds based on Ir and Ru are candidate materials for high-temperature applications, notably as spark plug electrode (SPE) materials. The high thermodynamic stability and resistance to deformation at elevated temperature have also profiled these alloys for structural applications. Of particular interest are the systems based on IrAl (B2), Ir which refine grain size. However, earlier studies showed that, in an which refine grain size. However, earlier studies of oxygen (on the order atmosphere containing a low partial pressure of 1 mPa), the dissolution of the Ir thorium to the surface to form ThO and reduced impact leading to anomalous growth of near-surface grains specimens were exposed to oxygen partial strength. In this study, of 1230, 1280, and pressures of 1.3 and 13.3 mPa at temperatures 1330 the However, anomalous growth of near-surface grains in this alloy. data also show that there is no significant difference in grain size or grain growth rates for the 1.3 versus 13.3 mPa oxygen levels. This tends to indicate that, at least under these exposure conditions, grain growth in DOP-26 is controlled by the outward diffusion of thorium rather than the inward diffusion of oxygen. This is supported by Auger results which show a depletion of thorium as one moves from the interior towards the surface. Research sponsored by the Office of Space and Defense Power Systems of the U.S. Department of Energy. This work was performed for the Department of Energy at the Oak Re- managed by Lockheed Martin Energy Ridge National Laboratory, search Corporation, under contract DE-AC05-96OR22464. 2:20 PM Oxidation Behaviour of Iridium-Based Intermetallic Com- pounds Doped with Boron Oak Ridge, TN 37831-6115 USA; 1 Union Rd., Fairfield, OH 45014 USA; 17404 USA PA York, 1301 Smile Way, ventive Care Div., oxygen-containing The grain-growth behavior in a low-pressure desig- This alloy, atmosphere of an Ir-0.3 wt.% W alloy was studied. oxide fuel in nated DOP-26, is used for cladding of 238-plutonium A small amount of radioisotope thermoelectric generators (RTGs). properties through added thorium (~60 wppm) improves the impact to and strengthening the two different mechanisms: (1) by segregating grain boundaries and (2) by forming Ir 2:00 PM on the Grain Growth Effect of a Low Partial Pressure of Oxygen Characteristics of Iridium Alloys Session Chairs: George, P. 62001 Russia; Easo Strength Lab., Ekaterinburg Oak Metls. and Ceram. Div., Laboratory, Oak Ridge National Ridge, TN 37831-6093 USA Tuesday PMMarch 14, 2000 Jackson A/B Room: Sponsored by: Sponsored Metals Committee Organizers: Program H. Harada, TN 37831-6083 USA; Oak Ridge, Laboratory, 305 Ibaraki for Metals, Tsukuba, National Research Institute Engelhard-CLAL, Careret, NJ 07008 Japan; R. D. Lanam, Ekatrinburg Ural State University, USA; Peter Panfilov, 62001 Russia International Symposium on Iridium: Symposium International and Diffusion Oxidation W. Cohron W.

TUESDAY PM 101 intercrystallite diffusion parametersof57Coinpoly-W andpoly-Irat ary coreevenat such lowhomologoustemperatures as0.2Tmelt.The high occupancyof stateswhicharelocalizedoutside thegrainbound- tions. Existenceofthetwo-dimensional diffusionfluxprovidesthe In poly-Irtwo-dimensionaldiffusion flowwasrealizedatthesecondi- homologous temperatures,which are extremelylowforFCCmetals. file typeshowedthataone-dimensional diffusionflowwasabsentat diffusion zonewasremoved.Functions sensitivetothediffusionpro- radiation fromtherestofsample leftafterpartoftheintercrystallite ments ofintensitysingle-energycomponentstheatomicprobe included traditionalmeasurementsof“layeractivities”andmeasure- formed. Thesectioninganalysisofthediffusionzonewasused. It mation andsubsequentrecrystallizationofasinglecrystalwasper- atomic probesinpolycrystallineiridium(poly-Ir)producedbydefor- Thepioneeringstudyofintercrystallitediffusion57Coand195Au 620219 Russia Metal Physics,RussianAcad.ofSci.,S.Kovalevskaya18,Ekaterinburg cessing Plant,LeninAve. 8,Ekaterinburg 620014Russia; Timofeev Kaigorodov Iridium in Polycrystalline Grain-Boundary Diffusionof57Coand195AuAtomicProbes 4:30 PM of Ir-addedFeAlalloyswillbealsodiscussed. atmosphere. Effectofvacancyonmechanicalpropertyandoxidation thermogravimetry-differential thermalanalysisat1273Kinan0 temperature. Oxidationbehaviorwasevaluatedusingsimultaneous ness testsatambienttemperatureandcompressionelevated terization. MechanicalpropertieswereinvestigatedbyVickers hard- to 1773KandX-raydiffractometrywerecarriedoutforalloycharac- cal analysis,opticalmicroscopy, differential scanningcalorimetry up ing heatingtreatmentswereadditionallycarriedout.ICP-OESchemi- under 70MPainvacuum.Vacancy-eliminating andvacancy-introduc- powders of99.9%purity. RHPwascarriedout at 1523Kfor10.8ks fabricated byareactivehotpressing(RHP)methodusingelemental additional IrmustsubstituteFesites.TheseIr-addedFeALalloyswere and 40mol%AL0(binaryFeAl),15milIr,where Concentrations ofAlandIrweresystematicallychangedtobe30,35, erties andoxidationresistancewereinvestigatedforB2FeAlalloys. Effectsofmicro-andmacro-alloyingwithIronmechanicalprop- 8577 Japan 8577 Japan; Hanada FeAl Alloys Mechanical PropertiesandOxidationResistanceofIr-Added 4:10 PM dium, whatisthecauseforfailureofiridiumcontainers. iridium. Onthecontrary, liquidzinc,aluminumandtindissolveiri- samples contactedwithmelts.Despitethistheydonotembrittled noble metalsandled,whilethinfilmsofAuAgappearonthe It wasshownthatiridiumdoesnotchemicallyinteractwithmelted Ag, Au,Pb,Sn,Zn,andAlinvacuumisthesubjectsforcurrentwork. melted metalsduringlongtime.Studyofiridiumcontactedwithliquid scraps, inasmuchasitisthesolemetalthatcanbeincontactwith for pyrometallurgicalextractionofgoldandsilverfromindustrial Newestareaforapplicationofiridiumismanufacturereactors 620014 Russia cessing Plant,TheHeadofRsch.Ctr., LeninAve. 8,Ekaterinburg Timofeyev posed toMeltsofChemicalElements On BrittleFractureofIridiumandIridium-BasedAlloysEx- 3:50 PM 3:40 PMBreak tion andexpansionofdiffusionzonewillbediscussed. material werevacuumannealedat1950 from conformingmoltensalts.Representativesamplesofcomposite was obtainedbysuccessiveelectrodepositiontoformIrandRelayers mutual diffusionofbimetalcompositionsiridium-rhenium,which result ofinterdiffusioncomponents.Inthiswork,wehavestudied structure, strengthandcorrosionpropertiesofcompositematerialasa temperature requiresthatallowancebemadeforpossiblechangesof 2 ; 2 ; N.I.Timofeev 1 1 2 University ofTsukuba, Instit.ofMatls.Sci.,Tsukuba 305- ; ; S.A.Matveev : A. V. Ermakov 2 Tohoku University, Instit.ofMatls.Sci.,Sendai980- H. Hosoda 1 ; K.Yoshimi : 1 1 2 ; ; ; V. K.Rudenko A. V. Ermakov 1 1 Ekaterinburg Non-FerrousMetalsPro- Ekaterinburg Non-FerrousMetalPro- 2 ; S.Miyazaki ° C fordifferenttime.Forma- : V. A.Dmitriev 1 1 ; G.N.Tatarinova ; S.M.Klotsman 1 ; S.Watanabe 2 Institute of 1 2 2 ; N.I. ; V. N. ; A.N. 2 ; S. 2 Brewer Chem Eng.&Matls.Sci.,Davis,CA95616USA Alexandra Navrotsky, UniversityofCalifornia,Dept. Dept. ofMet.&Matls.Eng.,Tuscaloosa,AL35487USA; Session Chairs: March 14,2000 Tuesday PM Materials Engineering,Tuscaloosa,AL35487USA Reddy, UniversityofAlabama,DepartmentMetalsand University ofChicago,IL60637USA;Ramana Madison, WI53706-1595USA;Dr. SusanMeschel,The Wisconsin, DepartmentofMaterialsScience&Engineering, nati, OH45221-0012USA;Y. AustinChang,University of Department ofMaterialsScienceandEngineering,Cincin- Program Organizers: Process FundamentalsCommittee Division, Thermodynamics&PhaseEquilibriaCommittee, Critical Technology Sector, Extraction&Processing Sponsored by: Session IV ture ThermochemistryofMaterials: Kleppa SymposiumonHighTempera- to thesametypeofinteratomicinteractionsind-transitionmetals. comparable homologoustemperaturesarenearlyequal.Thisfactisdue Japan Metallu. andMatls.Sci.,Hongo 7-3-1, Bunkyo-ku,Tokyo 113-8656 ent Elements Solutions fromFundamental Physical QuantitiesofConstitu- A ModelforPredictingThermodynamic PropertiesofMetallic 3:00 PM 850K wasdetermined. of Al2.98x10-3forthemolefraction0.48inTi-Alalloys at showed alarge negativedeviationsfromthe Raoult’s law. Theactivity ture range820to900K.Experimentalresults,activitiesofAlinalloys method. Theemfofconcentrationcellwasmeasuredinthetempera- ActivitiesofAlinTi-Alalloysweredeterminedusingtheemf fornia, Chem.Dept.,M.C.1460,Berkeley, CA94720USA Box 870202,Tuscaloosa,AL35487-0202USA; Thermodynamic PropertiesofTi-AlAlloys 2:30 PM will beanewassessmentofthesystem. and comparedtoexistingdataavailableinliterature.Theultimatetask some solidandliquidsolutions.Theexperimentalresultswillbegiven tion calorimetryformostofthebinaryintermetallicsaswell probe analysis.Enthalpiesofformationweremeasuredbydirectreac- Equilibria werecharacterizedbyX-raydiffractionandelectronmicro- pure metalsandannealingat1000 system. Alloysweresynthesizedbyreactionbetweenpowdersofthe study ofbothphaseequilibriaandenthalpiesformationinthis available resultsareconfusing.We haveundertakenanexperimental ing thebehaviorofmanyindustrialalloys.Atsametime, Al-Cr-Nbisoneoftheternarieswhichinterestinunderstand- B.P. 239,Vandoeuvre, Cedex54506France Henri Poincare,Lab.deChimieduSolideMin.,UMR7555Nancy1, Metallu. etRheo.desMat.,B.P. 28/S,AgadirMorroco; Mahdouk A ThermodynamicStudyoftheAl-Cr-NbTernary System 2:00 PM 2 ; 1 ; JeanClaudeGachon 1 The UniversityofAlabama,Metallu.andMatls.Eng.,P. O. : Peng Fan ASM International:MaterialsScience Ramana Reddy, University ofAlabama, Location: OprylandConventionCenter Room: LincolnE Ray Y. Lin,UniversityofCincinnati, 1 ; 1 The UniversityofTokyo, Dept.of 2 ; ° 1 C followedbywaterquenching. Universite IbnouZohr,Thermo. : 2 R. G.Reddy University ofCali- 2 Universite : 1 Kamal ; Leo

TUESDAY PM 102 Evergreen Energy Technology Corpora- Technology Energy Evergreen 1 ; 1 Khershed P. Cooper, Naval Research Cooper, Khershed P. Room: Bayou B Location: Opryland Convention Center Fernand Marquis, South Dakota School of Materials Processing and Manufacturing Kuochih Hong : 2:00 PM Opening Remarks and Introductions: Powder Materials Commit- Primary Organizer, Cooper, Khershed P. tee Liquid Metal Atomization: Fundamen- Liquid Metal Atomization: and Visual- tals and Practice: Overview ization Sponsored by: multicomponent systems. Two candidates are the In-Sn-Zn and Al-Sn- the In-Sn-Zn are candidates Two systems. multicomponent and investigations lattice parameter measurements, DTA Zn systems. dia- the phase to determine performed were analyses micro-probe and calorimetric by emf was obtained date The thermodynamic grams. were the ternary phase diagrams Based on this data measurements. of the bulk theoretical investigation different models. A optimised by through the alloys has been made surface of liquid solder as well as the such as of various properties concentration dependence study of the diffusion, long wavelength limit, fluctuations in the concentration theory A statistical mechanical and surface composition. surface tension for has been used to develop expressions based on the layered structure surface composition in the frame-work of self- the surface tension and formation models. association and compound 5:10 PM and Their Application to Hydride Hydrogen Storage Alloys Batteries Taiwan tion, Taipei, in a suitable metal as a solid metal hydride. Hydrogen can be stored applications for the metal hydride technol- There are many potential development of commercial The most important one today is the ogy. ad- A metal hydride battery has many rechargeable hydride batteries. cadmium battery such as (1) much higher capac- vantages over a nickel and, (3) no environmental pollution. Not (2) no memory effect ity, as a hydrogen storage/ every hydrogen storage material can be used storage electrode hydride electrode. The criteria of useful hydrogen based on thermody- alloys will be discussed. A semi-empirical formula, and/or develop a useful namic and electrochemical approach to predict Abx, is presented. There are two major alloy hydride electrode alloy, earth metal-based alloy, systems: Abx titanium-based and Abx rare In general, a titanium- currently used in the nickel hydride batteries. capacity than that of a based alloy can have a higher electrochemical a sealed nicked hydride battery However, rare earth metal-based alloy. material of the anode using a rare earth metal-based alloy as the active including high generally has a better electrochemical performance, and lower inter- working potential, high rate charging and discharging of making a nickel nal pressure during overcharging. A brief discussion several examples of hydro- hydride battery will be described. Finally, and electro- gen storage electrode alloys and their thermodynamic chemical properties will be presented. Division, Powder Metallurgy Committee Organizers: Program Division, Technology Materials Science and Laboratory, DC 20375-5343 USA; Frank Biancaniello, NIST, Washington, MD 20899-8556 USA; Stephen D. Ridder, Gaithersburg, MD 20899-8556 USA Gaithersburg, NIST, Tuesday PM March 14, 2000 Session Chairs: Dept. of Matls. & Metal Eng., Rapid Mines and Technology, Naval Cooper, P. SD 57701-3995 USA; Khershed City, DC Washington, Matls. Sci. & Tech., Research Laboratory, 20375-5343 USA ; 1 Uni- 1 ; C. T. ; 1 1 ; Kazuhiro 2 Tokyo Insti- Tokyo 2 J. H. Zhu A. Mikula Taichi Murakami Taichi : : : ; Masahiro Susa 1 ; Miyuki Hayashi 1 Tokyo Institute of Technology, Chem. and Matls. Sci., 2- Institute of Technology, Tokyo 1 ; Oak Ridge National Laboratory, Mets. and Cer. Div., P.O. Box P.O. Div., Mets. and Cer. Oak Ridge National Laboratory, 1 1 ; 1 versity of Vienna, Instit. of Inorg. Chem., Waehringerstrasse 42, Vienna Chem., Waehringerstrasse Instit. of Inorg. versity of Vienna, A-1090 Austria Lead-tin solders are commonly used in the electronic packaging due to their unique combination of electrical, chemical, physical, thermal and mechanical properties. Since lead alloys cause great environmental concern and health hazards it is more economical to replace lead in get the solder materials instead of cleaning up the electronic waste. To same or better properties it is therefore necessary to investigate some 12-1, Ookayama, Meguro-ku, Tokyo 152-8552 Japan; 152-8552 12-1, Ookayama, Meguro-ku, Tokyo Nagata Metallu. and Ceramic Sci., 2-12-1, Ookayama, tute of Technology, 152-8552 Japan Meguro-ku, Tokyo Exhaustion of fossil fuel and minimization of carbon dioxide emissions have been serious and urgent problems in the current steelmaking further development, aiming at From this point of view, industry. more efficient operations in the ironmaking process, is required for is one of the most effective Temperature the coming 21st century. operational factors in the ironmaking process, which is a key to reduce consumption of energy and emission of carbon dioxide. In order to make production of pig iron at temperatures as low as possible, better understandings of the carburizing reaction of solid iron are essentially required. In the present paper, reactions between solid iron and graphite have been observed in situ using a high-temperature microscope which enables a sample to be heated up to 1473K in one minute. The effect of oxygen potential on the carburizing reaction is also discussed. 4:40 PM In-SnZn and Al-Sn-Zn New Solder Materials Hiroyuki Fukuyama 2008, Bldg. 4500S, MS 6115, Oak Ridge, TN 35831-6115 USA 2008, Bldg. 4500S, MS of binary and ternary Laves phases Thermodynamic properties and reviewed. The enthalpies of forma- have been critically surveyed Dr. have been determined recently by tion of many Laves phases using the high-temperature calorimetry. Kleppa and his coworkers of formation of many Laves phases are now The vibrational entropies properties of also available. Some regularities in the thermodynamic data. A thermody- Laves phases were deduced using the experimental the size ratio limits for namic interpretation is offered to explain the ideal size ratio Laves phase formation. As the deviation from of formation decreases increases, the maximum negative enthalpy ex- elastic strain energy which is assumed to be due to the linearly, =1.03 and 1.65, the pended in compressing the atoms. At RA/RB deviation in the RA/RB enthalpy of formation reaches zero. Further positive. Thus, the free ratio will lead to the enthalpy of formation to the negligible entropy energy of formation becomes positive, due can only be stabilized in of formation term. Therefore, Laves phases of formation of certain atomic size, RA/RB, ratios. The enthalpies semiempirical Miedema many binary Laves phases were calculated by the available experimental model, which showed good agreement with the the importance of understanding thermodynamic prop- data. Finally, point defects, and erties of Laves phases in predicting phase stability, glass formability in these phases is discussed. 4:10 PM of Solid Iron with In Situ Observation of Carburizing Reaction Oxygen Potentials Graphite under Different A new model for predicting thermodynamic properties of metallic of properties thermodynamic for predicting new model A ele- of constituent quantities physical fundamental from the solutions geometrical new generation based on the has been developed, ments inter- equations for model. The Miedema Chou and proposed by model activity coef- systems and for in multi-component action parameters have been in ternary systems excess Gibbs free energy ficients and that it is on these equations show discussions derived. Theoretical model than generation geometrical using the new more reasonable model. model and Kohler as Toop geometrical models such using other in a interaction parameters has been applied for predicting This model solutions, and the agreement between predic- large number of metallic data is reasonable. tion and experimental 3:30 PM Break 3:40 PM of Laves Phases Thermodynamic Properties Liu

TUESDAY PM 103 Qingzhou Xu Fundamental FluidDynamicsinLiquidMetalAtomization 3:15 PMInvited or ultrasonicassistedatomization. atomization (bypouringthemeltontoarotatingdisc),andultrasonic instance two-fluidatomization(gas/meltandwater/melt),centrifugal most commonlyandcommerciallyusedatomizationtechniquesasfor paper confinesthediscussionoffundamentalsandpracticeto and solidificationconditionsoftheparticlesinspraycone.The including themeltbreak-upmechanismandendingwithcooling and masstransferbalancesstartingatthemeltflowintundish, and tailormadeprocesses.Thefundamentalsmainlydealwiththeheat of theliquidmetalsrequiresspecialmaterials,purpose-builtdevices keep themeltliquidwhichoftenincombinationwithahighreactivity of heatenergyat,inmostcases,hightemperaturelevelsorderto reference tothehighsurfacetensionofmajoritymelts)butalso the devices.Itisnotonlysupplyofhighkineticenergy(with a limitationofthevarietythosetechniquesandinmodifications omization comparedwithnormalliquidsthisinconsequenceresults interesting metalmeltsneedsignificantlyhighertemperaturesforat- liquids, suspensionsoremulsions.Butsincemostofthetechnically zation techniquesof“normalliquids”,i.e.aqueousoroil-basedpure most ofthem,inprinciple,showmoreorlesssimilaritytotheatomi- Atomizationofliquidmetalscanbeachievedinavarietyways, Badgasteiner StraBe3,BremenD-28359Deutschland 3:45 PMBreak surface intheinitialstage. velocity fieldsincetheincomingatomizationgasbouncesoffon its tion, theprotrusionlengthofdeliverynozzlealsoinfluences the pressure, deliverynozzlegeometryanditsprotrusionlength.Inaddi- occur there.Theaspirationpressureisdeterminedbyatomization tion) pressurezoneswithrespecttotheatmosphericmay vicinity ofthedeliverynozzle;andmeanwhile,negative(oraspira- chamber atahighspeed,recirculatingflowfieldsoftenformin the mospheric environment.Whentheatomizationgasentersinto the metal deliverynozzle,andthen,spreadsdeceleratesintothe at- typically underexpanded.Itisconicallyfocusedinfrontoftheliquid tion gasattheexitofatomizerreachesspeedsoundand is low pressurechamber. Under highatomizationpressures,theatomiza- the orificeofanatomizerfromhighpressuregasreservoirinto the atomization gasisacceleratedtoacertainvelocityasitexpandsthrough process. Thecalculatedresultsaresummarizedasfollows.Atfirst,the eters andgeometricarrangementsduringtheliquidmetalatomization ity andpressurefieldsaswelltheinfluencesofprocessingparam- Computationalfluiddynamictechniquesareusedtoanalyzeveloc- nology, Dept.ofMatls.Sci.andEng.,Cambridge,MA02139USA Matls. Sci.,Irvine,CA92697USA; 1 Bauckhage Liquid MetalAtomization:FundamentalsandPractice 2:45 PMInvited atomization aredelineated. are illustrated. To conclude,trendsand challengesinindustrial-scale yield andparticlesizedistributionontheeconomicsofatomization respect totheproductionoffinepowders.Theimportancepowder and centrifugalatomizationtheirimplicationsconsideredwith are assessedforcommercialandnear-commercialwater,gas,vacuum size distribution,shape).Empiricalrelations,modelsandmechanisms properties andprocessingconditionsonpowdercharacteristics(size, tion arereviewedwithparticularreferencetotheinterplayofmelt Thefundamentalsandindustrialpracticeofliquidmetalatomiza- delphia, PA 19104USA 1 Metal PowderProductionViaMeltAtomization 2:10 PMKeynote Drexel University, Dept.ofMatls.Eng.,LeBowBldg.,Phila- University ofCalifornia,Dept.Chem.andBiochem.Eng. 1 ; 1 ; Yizhang Zhou 1 Universitat Bremen,InstitutfurWerkstofftechnik, 1 ; GerardoTrapaga 2 Massachusetts InstituteofTech- 2 ; EnriqueJ.Lavernia : Alan Lawley : Klaus 1 1 : ; ; Phase-Doppler-Anemometry Analysis ofMoltenMetalAtomizationProcessUsingModified 5:00 PM ered geometries. ments producedimprovementsinthefinepowderyieldofconsid- concluded thattherecommendationssuggestedbyfluidexperi- results, anumberof316SSproductionrunswereperformed,anditwas yielded morespatialresolutionofthephenomenaathand.Usingthese computational fluiddynamicmodels,whichalthoughnotasaccurate, geometries. Theaspirationresultswereconfirmedwiththehelpof designed todeterminetheaspirationperformanceoftwoprototype fans, shearlayers).Withthisinformationathand,anexperimentwas location ofimportantflowfeatures(e.g.,shockwaves,expansion the flowwasvisualizedviaschlierenphotographytodetermine using anumberofpreviouslypublishedresearchtechniques.Initially Theperformanceofacommercialgas-metalatomizerwasstudied Gaithersburg, MD20899USA with highyieldslessthan20micronsusingAr, N methods ofproducingrapidlysolidifiedfinemetalandalloypowders atomization method,hasprovedtobeoneofthemosteffective Highpressuregasatomization(HPGA),aclose-coupled,discretejet 2 zation Gas FlowImagingandHighSpeedPhotographyofAtomi- 4:00 PMInvited the metalatomizationprocessisdemonstrated. parison betweenmeasuredPDAresultsandofsimulations of for inflightdiagnosticsonindividualparticles.Furthermorethecom- water filledtubesandwithresultsobtainedusingainfraredpyrometer techniques includingsieveanalysisofparticles,thatarecollectedusing sults arecomparedtoresultsreceivedwithdifferentmeasurement spray conecanbeobtained.FortheparticlepropertiesPDA re- for instancethedeterminationoflocalmassfluxdistributions the ticle sizeandvelocitydistributionsbutalsoadditionalinformation as optical measurementmethodnotonlycharacterisationoflocalpar- of amovedatomizerareshown.Withthismodifiednon-intrusive, Phase-Doppler-Anemometry resultsobtainedbyexaminingthespray the PDAtechnique.To demonstratethesensibilityofmodified particles intheliquidatomizationprocessrequiredmodificationof spheres withsmoothsurfaces,theopticalbehaviourofsolidifying applied toconventionalmaterials,e.g.smallwaterdropletsormetal vestigate sprays.Sincestandardphase-Dopplersystemscaneasilybe Phase-Doppler-Anemometry(PDA)isanappropriatetooltoin- Bremen 28359Germany Uhlenwinkel P. I.Espina omizer Optimization ofanAnnularJetCommercialGas-MetalAt- 4:30 PMInvited W-7405-Eng-82 andtheUSNavalResearchLaboratory. pects ofthisworkweresupportedbyUSDOE-BESundercontractno. during HPGAprocessingcanbederivedfromthisdata.Differentas- understanding ofthemeltdisintegrationmechanismsthatoperate presented, includingbriefhighspeedmovieselections.Anenhanced and cinematographycharacterizationoftheHPGAprocesswillalsobe jets andfullgasjetensemblesusedforHPGA.Highspeedphotography flow characteristicsofconvergentandconvergent-divergentsingle succession ofHPGAnozzles.Thispresentationwillcomparethegas process haveprovidedvaluableinsighttoguidethedevelopmentofa tion ofgas-onlyflowsandhighspeedphotographytheatomization University, AmesLab.,126MetalsDev., Ames,IA50011-3020 USA; Crucible Research,Pittsburgh, PA 15205USA : : Iver E.Anderson Aaron Johnson 1 ; G.J.DelCorso 1 ; 1 Universität Bremen,FB4/FG01,Badgasteinerstr. 3, 1 ; FrankS.Biancaniello 1 ; R.L.Terpstra 1 ; : 1 NIST, Fluid FlowGrp.,100BureauDr., Jens Ziesenis 1 ; JasonTing 1 ; Jörg Tillwick 2 1 , orHegas.Visualiza- ; StephenD.Ridder 2 ; 1 Iowa State 1 ; Volker 1 ;

TUESDAY PM 104 ; 1 ; V. 1 ; P. Juchmann ; P. 1 Panayiotis Tsakiropoulos ; 1 University of Hanover, Instit. University of Hanover, 1 ; 1 H. Haferkamp : Tim Mitchell Tim : particles could act as barriers to the propaga- particles could act as 12 ; T. Phan-tan ; T. 1 Al 17 -Mg β ; M. Niemeyer 1 University of Surrey, Schl. of Mech. and Matls. Eng., Guildford, Sur- University of Surrey, Kaese 1 rey GU25XH England Physical vapour deposition is suitable for the production of Mg-TM microstructures of PVD alloys consist of columnar alloys. Typical grains and exhibit inter-columnar porosity and chemical inhomogene- the latter being present in bands growing perpendicular to the ity, direction of growth of the columnar grains during deposition. Porosity and chemical inhomogeneity are detrimental to the mechanical properties and the corrosion resistance of the alloys. In situ mechanical working by flailing has been used previously to reduce porosity and eliminate columnar crystals in the microstructures of PVD deposits. In this work flailing was used in the production of PVD Mg-xTi (x=8, 14, 26, 34, 40 and 48wt%) alloys. The microstructures and surfaces of alloys in the as deposited condition and after immersion in 3wt% NaCl were characterised by electron microscopy and surface analysis techniques. The solid solubility of Ti in Mg was extended to 48wt%Ti by PVD. Flailing eliminated the columnar structure and reduced porosity locally in the regions where mechanical working was applied. In these regions there was some evidence of recrystallisation of the microstructure. The corrosion resistance of the flailed alloys decreased with increasing alloying content and was inferior to the corrosion resistance of PVD Mg. This behaviour has been attributed to the localised effects of flailing, with preferential attack occurring along the flailing lines leading to exfoliation of the deposits. therefore of technological significance with regard to the corrosion with regard significance of technological therefore of the investigations alloys. TEM/SEM Mg-Al-based of the properties that revealed morphologies the corrosion and microstructure as-cast (1) the on alloys is dependent studied of the resistance the corrosion where corro- particles and types of small Mn-containing distribution the barrier ef- fissures, (2) form to initiate corrosion sion pits could types of manga- in the alloys. Two fissures propagation fects for the I is a Type in the alloys studied. phases were found nese-containing morpholo- of equiaxed or short-bar phase and type II is flower-shaped a much higher Al/Mn ratio and II particles have a lower gies. The type than the type I phase. The type II particles cathodic reaction rate form pits and initiate corrosion fissures. The could provide sites to higher Al content adjacent to the grain bound- segregated regions of aries and the tion of corrosion fissures. 3:15 PM and Perspectives of New Mechanochemical Characteristics Magnesium-Lithium-Alloys Nichteisen-Metallurgie, Applestrasse 11a, of Matls. Sci., Fachgruppe Hannover 30167 Germany in tendencies towards an ecological increase On the base of growing it is the light weight efficiency of technical products and processes However, its ba- material magnesium that enjoys recurrent attention. of alloys that sic attraction is presently spoiled by the deficiency the general as- doesn’t allow more complex applications. Therefore improving creep resis- pects of the alloy development are focused on well as the increase of tance and enhancement corrosion resistance as aim of current research activities at the Institute of The plasticity. Materials Science is the development of Magnesium-Lithium-alloys corrosion resis- high ductility and high with further lowered density, a discussion of phase tance. The presented research work includes and corrosive proper- constitutions and their impacts on mechanical alloyed cph Magnesium- ties. A variety of Aluminium and Silicium tensile or impact Lithium-materials is tested. Investigations include corrosion test and bending tests, potentiostatic tests, atmospheric to Mg standard water vapour cabinet. The materials are compared shows supe- materials. A selection of Magnesium-Lithium-materials to representative rior strength and ductility properties in comparison of the active standard Magnesium materials. Principal mechanisms presented and used to corrosion protection of Magnesium alloys are achieve a satisfying corrosion resistance. 3:40 PM Break 3:50 PM In Situ Mechanically Microstructure Property Studies of Alloys Mg-Ti PVD Worked Guilian ; Darryl 2 ; Darmstadt 1 1 ; 1 ; C. Berger 1 ; Terje Kr. Aune Kr. ; Terje 2 Ford Research Laboratory, Matls. Ford Research Laboratory, Hydro Magnesium, Magnesium 1 3 ; 1 : Vladimir Tchervyakov ; M. Gugau 1 Howard I. Kaplan, Magnesium Howard I. Room: Bayou C Convention Center Location: Opryland ; Håkon Westengen ; Gerry Cole 1 1 Eli Aghion, Dead Sea Magnesium, Potash Eli Aghion, Dead Sea Norsk Hydro ASA, Rsch. Ctr. Porsgrunn, P.O. Box Porsgrunn, P.O. Norsk Hydro ASA, Rsch. Ctr. Light Metals Division, Reactive Metals Division, Reactive Light Metals 2 ; E. Broszeit 1 Luleå University of Technology, Div. of Eng. Matls., Luleå Div. Luleå University of Technology, 1 J. Senf ; 3 Liu-Ying Wei Liu-Ying : ; John Bomback : 1 Albright S97187 Sweden; 2560, Porsgrunn N-3901 Norway; Gao USA 39209 Six Mile Rd., Ste. 200, Livonia, MI 48152 Market Dev., Manganese is an element often used to remove iron from the magnesium melts in order to produce high purity magnesium alloys. A study of manganese-containing particles in the magnesium alloys is Sci. Dept., MD 3182 SRL, 20000 Rotunda Dr., Dearborn, MI 48121 Sci. Dept., MD 3182 SRL, 20000 Rotunda Dr., USA Galvanic corrosion of magnesium alloys is the major issue in corrosion reliability of Mg alloys in automotive applications. Anodization is a very effective way of corrosion protection for magnesium alloys. In this paper, the corrosion resistance of AZ91 alloys with different surface treatment (bare, anodized, anodized and sealed) were compared. Electrochemical test results showed that anodization not only improves general corrosion resistance, but also significantly increases its resistance to galvanic corrosion. Sealing the anodized film is also shown to further improve the corrosion resistance. 2:50 PM Characterisation of Manganese-Containing Intermetallic Par- ticles and Corrosion Behaviour of Die Cast Mg-Al-Based Al- loys University of Technology, Instit. of Matls. Tech., Grafenstr. 2, Grafenstr. Instit. of Matls. Tech., University of Technology, Darmstadt 64283 Germany is the chemical and One main disadvantage of magnesium alloys Consequences of electrochemical reactivity of this group of materials. reliability and lifetime of this reactivity are problems in functionality, High purity alloys machines and constructions made of these alloys. But looking at corrosion behaviour, have reduced corrosion sensitivity. is only one part of the the corrosion of magnesium alloys for itself other and maybe the corrosion problem. Galvanic corrosion is the for the gal- Typical main part, especially for machines and vehicles. in contact with each vanic corrosion of different metallic materials noble material. Magne- other is the enhanced corrosion of the minor used for machine sium alloys are the least noble metallic materials behaviour of four parts. In this paper corrosion and galvanic corrosion AS 41, AE 42) are pre- die cast magnesium alloys (AZ 91, AM 60, corrosion the magnesium sented and discussed. Looking at the galvanic alloys typically used in alloys were connected to different aluminium the automotive industry. 2:25 PM Resistance of An- Laboratory Evaluation of Galvanic Corrosion odizing Film on Magnesium 2:00 PM Die Cast Magnesium Corrosion and Galvanic Corrosion of Alloys Sponsored by: Sponsored Association International Magnesium Committee, Program Organizers: Magnesium Technology 2000: Alloy 2000: Technology Magnesium and Corrosion Development Tuesday PM Corporation of America, Salt Lake City, UT 84116 USA; UT 84116 City, of America, Salt Lake Corporation IL Argonne, Laboratory, National John N. Hryn, Argonne International Magnesium B. Clow, 60439-4815 USA; Byron 22101 USA VA Association, McLean, March 14, 2000 Session Chair: 84100 Israel House, Beer-Sheva

TUESDAY PM 105 phase diagramand thermochemicalpropertiestoexplicitly character- since early1970’s haschangedthisview. Thistechniquecouples the CALPHAD techniqueforcomputational thermodynamicsdeveloped has oftenbeenviewedapplicable to statesnearequilibriumonly. The terms ofthermodynamicandkinetic parameters.Thermodynamics ations. Theessentialfeatureisto expressthedesignobjectivesin modynamics, kineticsimulations, andexperimentalprototypeevalu- grates processing,structureandproperties throughcomputationalther- fields isthesystemsmaterialsdesign.Systemsdesigninte- in computationaltechniquesthepastdecade.Oneofemerging edge onalloytheoriesinthepastcenturyandsignificantprogress ment. Thesituationisnowchangingthankstotheaccumulatedknowl- theories tendtoexplainthebehaviorofmaterialsaftertheirdevelop- empirical approach,whichisusuallycostlyandtimeconsuming.Alloy Alloydevelopmentistraditionallyconductedby“make-and-see” sity Park,PA 16802USA Pennsylvania StateUniversity, Dept.ofMatls.Sci.and Eng.,Univer- Computational ThermodynamicsCanHelp A PerspectiveViewontheDesignofMagnesiumAlloys:How 5:05 PM parameters evaluatedusingtheleastsquaremethodarealsopresented. dissolution reactionAlNi=Al+Niisgiven.Thethermodynamic ity ofNiinequilibriumwithphaseAlNithemeltaccordingto more dominantasthealuminiumconcentrationincreases.Thesolubil- equilibrium withthemeltareAlNiandAl3Ni tion ofaluminium.SEManalysisshowsthattheprecipitatedphasesin alloys showsamarkedreductionofnickelsolubilitywithsmalladdi- parison ofnickelsolubilityinpuremagnesiumwithMg-Al the temperaturerange650-900 SolubilityofnickelinliquidMg-Al-Nialloyshasbeenmeasured Tech., Trondheim N-7465Norway Hydro ResearchCentre,PorsgrunnN-3901Norway; Electrochem., AlfredGetzVei 2B,Trondheim N-7491Norway; versity ofScienceandTechnology, Dept.ofMatls.Tech. and Jo Fenstad Above 650 Solubility ofNickelinMoltenMagnesium-AluminiumAlloys 4:40 PM tion ofZrinthesurfacesbothas-depositedandcorrodedalloys. extremely lowcorrosionrates,whichwereattributedtotheparticipa- of Vfromthesurfacefilmformedonalloys.Mg-Zrexhibited pure Mgorotheralloys,whichhasbeenattributedtotheabsence sion resistance.Mg-Valloysexhibitedlowercorrosionresistantthan Zr alloys.Thetwoalloysystemsbehaveddifferentlyregardingcorro- led toadecreaseofthec/aratiowithincreasingZradditionsinMg- of thea-latticeparameteranddecreasec decreased withincreasingVcontentintheMg-Valloys.Theincrease ceeded. Boththecandalatticeparameters,aswellc/aratio precipitated whentheextendedsolidsolubilityofVinMgwasex- decreased astheVandZrcontentinalloysincreased.Pure Zr (3.5at%)respectively. Thesolidsolutionbreakuptemperature were extendedapproximatelyto17.5wt%V(8.9at%)and10.5 tures andastrongbasaltexture.ThesolidsolubilitiesofVZrinMg deposits exhibitedcompositionalinhomogeneity, columnarmicrostruc- the as-depositedconditionandafterimmersionin3wt%NaCl.All have beenstudiedbybulkandsurfacecharacterisationtechniquesin Zr. InthispaperwewillreportonPVDMg-VandMg-Zralloyswhich loy designhasselectedcandidatesoluteadditionswhichincludeVand which couldimprovecorrosionresistanceinsalineenvironment.Al- to theformationofastableandifpossibleself-healingsurfacefilm, enced bytheneedforabeneficialcontributionofalloyingaddition alloys havebeenconsidered,wherethechoiceofTMhasinflu- properties andcorrosionresistance.AspartofthiseffortMg-TM been usedforthedevelopmentofMgalloyswithimprovedmechanical ment withsignificantlyhighermeltingpointthanMg.Thus,PVDhas suitable fortheproductionofMg-Xalloys,whereXisalloyingele- Physicalvapourdepositionisanon-equilibriumprocesswhich Matls. Sci.andEng.,Guildford,SurreyGU25XHEngland Tsakiropoulos Studies ofMg-VandMg-ZrAlloys 4:15 PM 1 ° ° ° ° ° ; ThorvaldAbelEngh C 1 : ; Harsharn SinghTathgar 1 University ofSurrey, Schl.ofMech.andMatls.Eng., ° C for1-10%aluminiumcontent.Com- 1 ; FredeFrisvold : 1 ; PerBakke Spyros Diplas 2 withthelatterbecoming : 3 Zi-Kui Liu ; 2 ; EivindØvrelid 1 3 Norwegian Uni- SINTEF, Matls. 1 ; Panayiotis 1 ; 2 Norsk 1 The 3 ; Rsch. andDev., Chester, VA 23831USA USA; DanielPaulCook,ReynoldsMetalsCompany, Corp. Dept. ofMatls.Sci.andMin.Eng.,Berkeley, CA94720 Session Chairs: March 14,2000 Tuesday PM Engineering, MIdM-89,Cincinatti,OH45215USA Edmonton, ABT6G2G6Canada;SulekhJain,GeAircraft MN 55414-2196USA;HaniHenein,UniversityofAlberta, Minnesota, SaintAnthonyFallsLaboratory, Minneapolis, Program Organizers: Modeling Analysis&ControlCommittee Processing andManufacturingDivision,Jt. Sponsored by: Modeling ofMaterialsProcesses Age III:PhysicalandMathematical Materials ProcessingintheComputer design ofmagnesiumalloys. series toZAalongwiththefutureactivitiesofsystems the Mg-Al-ZnternaryalloyscoveringcompositionrangefromAZ be discussed.Particularattentionwillpaidtothephaserelationsin magnesium alloyswillbeintroduced,andtheCALPHADtechnique this presentation,theconceptofsystemsmaterialsdesignappliedto able forthedesignofalloycompositionsandprocessingprocedures.In both equilibriumandnon-equilibriumconditionsareextremelyvalu- process variability, phaserelationsinmulti-componentalloysunder intermetallic phases.To developrobustalloysthatlesssensitiveto alloys, magnesiumalloysaremulti-componentinnaturewithmany for simulatingdynamicmicrostructureevolutions.Asallcommercial tion ofdrivingforcesbetweenanyintermediatenon-equilibriumstates The modelingofGibbsenergyindividualphasesenablesthecalcula- phases overawiderangeoftemperature,pressureandcomposition. ize allphasesinasystem,includingstable,metastable,andunstable Dept. ofMatls.Sci. andMin.Eng.,Berkeley, CA94720USA ten Metals A CapacitanceProbefortheMeasurement ofBubblesinMol- 2:50 PM design suggestedbyfurthermodel calculationswillbepresented. application, inletpressuremap, die coolingmodification,andmold tion inwheelcasting.Changes castingpractice,e.g.moldcoating used tovalidateseveralmathematicalmodelsoffillingandsolidifica- profile inthemoldsidecoresandfillingtime.Thisdatawas normal operation.Thisdatayieldedinformationsuchasthethermal ments wereconductedatanumberofpositionsinwheelmoldduring ducted inalow-pressurediecastingfacility. Temperature measure- years. Inthispaper,resultswillbepresentedfromplanttrialscon- tion slatedtoincreasealmost8millionperyearinthenexttwo currently producesroughly6.5millionwheelsperyearwithproduc- has beenmostsuccessfullyproducedinaluminum.ReynoldsMetals crease inthe1970’s. Thecarwheelisoneofthesecomponentswhich alloys hasbeenincreasingsincethepriceofgasolinestartedto in- Thepercentageofautomotivepartsmanufacturedfromaluminum Broadmoor SE,GrandRapids,MI49512USA Enon ChurchRd.,Chester, VA 23831USA; Dantzig Daniel P. Cook ing ofAluminumAutomotiveWheelCastingOperations Physical ExperimentationCoupledwithMathematicalModel- 2:30 PM 2 ; 1 Reynolds MetalsCompany, Corp.Rsch.andDev., 13203N. : QianFu 1 ; MelissaI.Bloch Extraction &ProcessingDivision,Materials James W. Evans,UniversityofCalifornia, 1 ; Location: OprylandConventionCenter Room: LincolnA James W. Evans Vaughan Voller, Universityof 2 ; Juergen Biermann 1 ; 1 University ofCalifornia, 3 SIMTEC Inc.,3663 3 ; JonathanA. :

TUESDAY PM 106 ; 1 Tohoku Tohoku 1 1 ; ; 1 1 ; Miao Wang 1 Ji He Wei ; Shoji Taniguchi 1 : ; Shoji Taniguchi 2 Lifeng Zhang ; Kaike Cai 1 : University of Science and Technology Beijing, Steel. University of Science and Technology 2 Lifeng Zhang : Shanghai University, Dept. of Metallic Matls., 149, Yan Chang Rd., Yan Dept. of Metallic Matls., 149, Shanghai University, University, Taniguchi Lab., Dept. of Metallu., Aoba-ku, Sendai 980- Taniguchi University, 8579 Japan; 1 Shanghai 200072 PRC the powder particles and The mass transfer characteristic between Blowing) refining was the liquid steel in the RH-PTB (Powder Top for a 90t RH degasser. investigated in a hydraulic model of 1/5 scale was used as the flux The sodium chloride powder with chemical purity of the liquid side were for blowing. The mass transfer coefficients influences of the main determined under the conditions of PTB. The rate were examined. technological parameters on the mass transfer coefficient on the liquid The results indicated that the mass transfer internal diameter of the side increases with raising the gas blowing rate, size, and decreases up-snorkel, circulation rate of liquid and powder down-snorkel. It was in with an increase of the internal diameter of the conditions of the present the range of (1.36-7.30)x10(-4) m/s under the were obtained. work. The appropriate dimensionless correlations 4:50 PM Mathematical Simulation of Fluid Flow in Gas-Stirred Liquid Systems Instit., Schl. of Metallu., Beijing 100083 PRC In the present paper, based on the two-phase (Eulerian-Eulerian) model, the 3D fluid flows in gas-stirred systems, i.e., air-stirred water vessel and argon-stirred liquid steel ladle, are simulated. In the Eulerian- Eulerian two-phase model, gas and liquid are considered to be two different continuous fields. The phases are assumed to share space in proportion to their volume fractions. The exchange between the phases is represented by source terms in conversation equations. Turbulence simulated by the model is assumed to be the property of the liquid phase. The following effects of mathematical treatments and operational factors on the fluid flow are discussed, such as interphase drag force, turbulent model, the size of bubble, and gas injection mode. Some interesting results are derived. Except the interphase drag force, the interphase lift force should be taken into accounted in order to exactly simulate the fluid flow in gas-stirred systems. Suitable turbulent model and drag coefficient have effect on the mathematical simulation. Injecting small bubbles can realize a well mixing flow condition. The distance between the two gas-injection nozzles has effect on the fluid flow. University, Taniguchi Lab., Dept. of Metallu., Aoba-ku, Sendai 980- of Metallu., Aoba-ku, Lab., Dept. Taniguchi University, 8579 Japan the 3D single-phase turbulent steady fluid flow In this paper, firstly stirred by a single impeller is mathemati- in a vessel with four baffles is modeled by using the standard model. cally simulated. Turbulence The flow domain is used to model the impeller. Sliding-grid method is as the inner one rotates at the same speed divided into two cylindrical, one is fixed with the baffles. Results indi- the impeller, and the outer zone is near the paddles, and larger stirring cate that the high-speed stirring in- The calculated flow velocity. fluid speed generates larger the analyze the experimental results. Secondly tensity data are used to size, gas flow rate and NaCl concentration, effects, such as filter pore by experiment. For the particle removal rate on bubble size are studied this vessel, first order kinetics is adopted. The by bubble flotation in flow rate, particle and effects of initial number of the particles, gas on the removal rate bubble size, stirring speed and surface condition, is derived by experi- constant are discussed, and an empirical equation to study the particle mental data. At last, a simple model is developed turbulent flow condi- attachment probability on bubble surface under tions. 4:30 PM Characteristic between Molten Steel Study on Mass Transfer and Particles in RH-PTB Refining contact angle and evaluating the interfacial tension between the sili- between tension the interfacial evaluating angle and contact various light of the in the are discussed The results and water. con oil as the as well such systems flow in in the viscous involved forces affinities. chemical Break 3:50 PM 4:10 PM in a Me- by Bubble Flotation and Particle Removal Fluid Flow Vessel Stirred chanically : Univer- 1 ; 1 Royal Institute of Tech- 1 ; 1 ; Brian G. Thomas 1 Hua Bai : ; Seshadri Seetharaman 1 ; Sichen Du 1 nology, Metallu. Dept., Brinellv. 23, Stockholm 10044 Sweden Dept., Brinellv. Metallu. nology, The viscosities of two-phase mixtures are of great importance in the modelling of the fluid flow in metallurgical processes. For example, in steelmaking and refining, the intimate mixing of metal droplets in the slag phase requires a consideration of the effective viscosities for the mixture. The present work was aimed at an understanding the phenomena underlying the viscous flow in a two-phase mixture with widely differing viscosities. Emulsions of silicone oils of known viscosities (3.45 dPa·s and 10.10 dPa·s at 293 K) with small amounts of water evenly distributed in the same were prepared by The subjecting the mixture to uniform stirring using a magnetic stirrer. The vis- uniformity of the emulsions was checked by photography. cosities of these emulsions were measured at constant temperature by The the rotating cylinder method using Brookfield Digital Rheometer. uniformity of the method of preparation of the emulsions was confirmed by the reproducibility of the results. The measured viscosities were generally found to be independent of the torque under the experimental conditions so that the two-phase mixture could be considered as a Newtonian liquid. The variations of viscosities with temperature and the effect of addition of a surface-active substance were also studied in this work. The measured viscosities were found to be higher than those of both pure water and silicone oil. The experimental viscosities showed a positive deviation from linearity and the deviation was found The influence of to increase with increasing concentration of water. surface tension on the viscosities was examined by the measurement of There are many metallurgical processes where bubbles are injected bubbles are where processes metallurgical are many There copper converters are Obvious examples melts. temperature into high These industry. the aluminum found in fluxing units chlorine and the not are therefore the melt within and the bubbles are opaque melts (nota- probes have been developed Electroresistivity readily observed. the frequency, groups) to measure and by Iguchi’s bly by Brimacombe’s work by liquid metals. The probes of bubbles in size and velocity a conductor contact between interruption of electrical detecting the melt, as a melt and the surrounding immersed in the (usually metallic) describes an alternative The paper the conductor. bubble intercepts a a measurement of the capacitance between probe which relies on as and the melt; that capacitance changes conductor within the probe the electroresistivity probe, this capacitance a bubble passes. Unlike is conductor in contact with the melt, rather it probe does not have its refractory material such as alumina. Conse- shielded by a sheath of withstand hostile environments and one such quently the probe can detecting bubbles for 30 minutes in molten probe has survived, while the describes the probe construction, illustrates aluminum. The paper metals and treats the deconvolution algo- signals it gives in molten to convert the bubble signals to useful rithm and software necessary information. 3:10 PM Nozzles during Continu- Argon Bubble Behavior in Tundish ous Casting of Steel Slabs Urbana, IL Green St., sity of Illinois, Mech. Eng. Dept., 1206 W. 61801 USA efficient and widely em- Argon injection into tundish nozzle is an continuous casting pro- ployed method to reduce nozzle clogging in quality by changing cess. It also affects casting operation and product this paper, a 3-D finite the flow pattern in the nozzle and mold. In liquid steel-argon bubble difference model is developed to study the tundish nozzles. Ex- multi-phase turbulent flow in continuous casting caster” to verify the periments are performed on a 0.4-scale “water with the measurements model by comparing the model prediction developed The technology. using PIV (Particle Image Velocimetry) of various variables model is then employed to investigate the effects slide-gate nozzle. Be- on flow patterns and jet characteristics for the continuous casting cause the input and output between the real-life different, HPQF model, operation and numerical simulation are usually variable numerical based on advanced curve fitting of the multiple the numerical model- results, is then developed and applied to convert with real-life operation ing results to present trends that correspond conditions. 3:30 PM Mixtures of Two-Phase Physical Modeling of the Viscosities Liu Wei

TUESDAY PM 107 W. GreenSt.,Urbana, IL61801USA of IllinoisatUrbana-Champaign, Dept.ofMatls. Sci. andEng.,1304 der Interfaces Microstructures andFatigue Resistance ofElectroless-Ni/Sol- 2:00 PMInvited Plantation, FL33322USA Session Chairs: March 14,2000 Tuesday PM Plated andDiscreteProducts,Spokane,WA 99216USA 3108 USA;MartinWeiser, AlliedSignalElectronic Materials, sity, DepartmentofMaterialsScience,Evanston,IL60208- tion, FL33322USA;GautamGhosh,NorthwesternUniver- Murray Hill,NJ07974USA;SriniChada,Motorola,Planta- Program Organizers: Materials Committee Division, ElectronicPackagingandInterconnection Sponsored by: Joints Reaction andReliabilityofSolder for ElectronicInterconnects:Interfacial Packaging &SolderingTechnologies tion andblowingintheRHrefiningofmoltensteel. mizing thetechnologyandprocessofdesulfurizationbypowderinjec- basis fordeterminingthereasonabletechnologyparametersandopti- may beexpectedtoprovidesomeusefulinformationandareliable effectively raisetherateofprocessinRHrefining.Themodel operation andincreasingthecirculationrateofliquidsteelmay ately be12-20min.Intensifyingthepowderinjectionandblowing (60-80)x10-4 mass-%.Thetotaltreatmenttimeneededwillappropri- molten steeltotheultra-lowlevelbelow(5-10)x10-4mass-%from t-steel, itisentirelypossibletodecreasethesulfurcontentin chemical compositionof85mass-%CaO+15CaF practice. Injectingandblowingthelime-basedpowderfluxwith ment withsomedataoftheindustrialexperimentsandproduction indicated thatthepredictionmadewiththismodelisingoodagree- eight circulationcyclesoftheliquidsteeltobetreated.Theresults ization undereachmodewassetuptobe24min,thatisequivalent and 10,8,6,5,4,3kg/t-steel.Thetotaltreatmenttimefordesulfur- tively assumedtobe0.007,0.006,0.005,0.004,0.003,0.002mass-% treated andtheamountsofpowderinjectionblowingwererespec- respectively. Theinitialcontentsofsulfurintheliquidsteeltobe injection andblowingrateweretakentobe100t/min150kg/min, model. Therelevantcirculationrateoftheliquidsteelandpowder blown inaRHdegasserof300tcapacitywerecarriedoutusingthe different initialcontentsofsulfurandamountspowderinjected lime-based powderfluxundertheassumedoperatingmodeswith Predicting andmodelingfortheprocessbyinjectingblowing being treatedfordesulfurization,weremorereasonablydetermined. transfer coefficients,theeffectivepowderamountinmoltensteel developed. Therelatedparametersofthemodel,includingmass balance ofsulfurinthesystem,akineticmodelforprocesswas lyzed. Basedonthetwo-resistancemasstransfertheoryand refining ofmoltensteelanditsmechanismwereconsideredana- ThedesulfurizationprocessbyinjectionandblowingintheRH 149, Yan ChangRd.,Shanghai200072PRC Zhu Blowing inRHRefiningofMoltenSteel A KineticModelofDesulfurizationbyPowderInjectionand 5:10 PM 1 ; Neng-Wen Yu : Pilin Liu Electronic, Magnetic&PhotonicMaterials D. Frear, Intel;SriniChada, Motorola, 1 ; 1 Shanghai University, Dept.ofMetallicMatls., Location: OprylandConventionCenter Room: LincolnD 1 ; ZhengkuiXu Hareesh Mavoori,BellLaboratories, 1 ; JianKuShang : Ji-He Wei 1 ; 1 2 ; Shou-Jun of3-5kg/ 1 University Korhonen Under BumpMetallizationsforLeadFree Solders 2:25 PM cial fatigueresistancebyreducingP-concentrationwillbediscussed. thermal processingconditions.Thepotentialforimprovinginterfa- highly dependentonphosphorousconcentrationinthenickeland cial microstructureandinterfacialfatigueresistance.Theeffectswere showed thatphosphoroushadastronginfluenceonboththeinterfa- microscopy andinterface-fracturemechanicstechniques.Theresults tance oftheNi-solderinterfaceswerestudiedbytransmissionelectron structure followingreflowandaging,theresultingfatigueresis- solved inthenickel.Inthiswork,changesinterfacialmicro- only bythereactionofSnandNi,butalsophosphorousdis- developed betweenelectroless-Nisolderalloysarecomplicatednot in bothflip-chipandBGApackages.Theinterfacialmicrostructures metallurgical reactionbetweensolderalloysandcoppermetallization Electroless-Niiswidelyusedasadiffusionbarrieragainsttherapid tallic layerformation andtheresultantsolderjoint microstructure. tions. Suchoperations canaffect thesolderability, interfaceinterme- Solderjointsusedinelectronic applicationsundergoreflowopera- Eng. Bldg.,EastLansing,MI48824-1226 USA Subramanian Mechanical Properties ofSolderReflowonWettability,Effects Microstructure and 3:05 PM with T/Ctest. test PCBboardwaspreparedandevaluatedthesolderjointreliability and crackpropagation,wereinvestigated.AlsotheDaisyelectrical ing, interfacialreactionandmicrostructuresuchascrackinitiationsite also applied.AfterT/Ctest(-65 To comparethesolderjointreliability, Sn-36Pb-2Agsolderballwas were placedonPCBboard,thentemperaturecycletestwasperformed. 0.7Cu ballswereattachedonLF-CSPpackagesandeachcomponents simulate therealsurfacemountingcondition,Sn-3.5AgandSn-3.3Ag- ber ofreflowcycleinconsideringtherealboardmounting,too. To joint strengthandthemicrostructuralchangewereobservedwithnum- temperature showedthesuperiorsolderjointstrength.The optimum reflowconditionandthespecimenspreparedbyhigher The differenttypesofreflowprofilewereinvestigatedtofindoutthe examined andanalyzedbyopticalmicroscopy, XRD,SEMandEDX. microstructure ofsolderjointinterfaceandbulkballwere and hightemperaturestoragetest(150 after environmentaltestssuchastemperaturecycles(-65 troless Au/Ni/Cusubstrate.Eachjointedsampleswerecharacterized pared byelectroplatingasNi,Sn/Ni,Ag/NionCualloyandwithelec- cial reactionandsolderjointreliability. Various substrateswerepre- 3.5Ag andSn-3.3Ag-0.7Cusolderswerestudiedinthefieldsofinterfa- To evaluatethePb-freesoldersinapplicationofCSPpackages,Sn- Memory Rsch.Div., Ichon,Kyoungki-do467-701Korea Chang JunPark (LF-CSP) Sn-3.3Ag-0.7Cu SoldersinLeadFrameChipScalePackage Interfacial ReactionandSolderJointReliabilityofSn-3.5Ag, 2:45 PM ability ofthejoints. slow reactionrate.Sheartestswerealsoperformedtoassessthereli- affects thereaction,andhowmuchNiisneededtoobtainasufficiently faces wereanalysedwithSEMtofindouthowtheNi-concentration fabricated andreflowedwithlead-freesolders.Thesolder/UBMinter- use aCuNialloy. Inthisstudy, UBM’s withdifferent CuNialloyswere Ni isaviablealternativeasthewettablelayer. Anotherapproachisto causes dewettingandfailureofthejoint.SinceSn-Nireactionisslower, reflow isveryintenseandcandepletetheUBMofcopper,which Sn, containlargeamountsoftin,sothattheSn-Cureactionduring Most commonlyusedlead-freesolders,suchaseutecticAg-SnandBi- ally Cu,musthavesufficient resistancetoreactionwiththesolder. sion, thewettablelayerofunderbumpmetallization,whichisusu- underbump metallizations(UBMs)areneeded.To obtaingoodadhe- Inordertouseleadfreesoldersinflipchipbonding,compatible versity, MSE,356BardHall,Ithaca,NY14853USA 1 : ; PengSu 1 Seung Wook Yoon ; 1 1 ; Michigan StateUniversity, Matls.Sci.&Mech.,3536 Jong Tae Moon 1 ; MattA.Korhonen : F. Guo 1 ; SungHakHong ° C~150 1 ; 1 1 ; S.Choi Hyundai ElectronicsCorporation, ° C) ofPCBboardlevelmount- ° 1 C). Theirfracturedsurface, ; Che-Yu Li 1 ; J. P. Lucas 1 ; Yoon HwaChoi 1 ; 1 Cornell Uni- ° : C~150 1 ; K.N. Tia M. ° C) 1 ;

TUESDAY PM 108 ; : 2 GIK 1 ; 1 ; Juergen Gamalski ; Juergen 1 ; M. Rashid 1 Siemens AG, Dept. ZT ME6, 2 ; John A. Williams 1 ; S. E. Benjamin 1 C and 85% RH. Average values for the readings for C and 85% RH. Average F. A. Khalid F. C and the resulting microstructure of the joints is resulting microstructure C and the ° ; James Brokaw ° 1 : Georgia Institute of Technology, Matls. Sci. and Eng., 778 Atlantic Institute of Technology, Georgia Institute of Engineering Sciences, Topi, Nwfp Pakistan Institute of Engineering Sciences, Topi, The importance of electronic interconnects have been increased with the advancement in technology due to the miniaturization of electrical components. This has also lead to an increase in the number of input/output terminations. Consequently not only the solder joints have increased but also the joint dimensions have decreased in electronic packages with increased speed and greater packaging density. However, reliability has become crucial because of their use to control operational and safety functions in aerospace and automobile applications. The present work focuses on the examination of microstructural features and their influence on the interfacial properties of substrate using optical, scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). A series of solder alloys with and without lead alloying developed were used to investigate interdiffusion 1 Atlanta, GA 30332-0245 USA; Dr., Siemensdamm 50, Berlin D-13623 Germany phones are becoming Wireless devices such as pagers and cellular low loss RF signal common consumer items. These products require and processing con- propagation which is affected by material choices series of no-clean solder ditions. This paper examines the effect of a which sends a broad- pastes on signal integrity using an RF test circuit switch and measures band RF signal through a gallium arsenide antenna The test circuit also mea- its transmission using a network analyzer. different test vehicles, sures signal leakage. This paper reports on two the other that used a 2.0 one that used a 900 MHz antenna switch, and GHz antenna switch. The transmission and leakage readings were taken daily for 20 days while the test vehicles were under accelerated aging conditions of 85 each solder paste were plotted to provide comparison among the pastes. The comparison data clearly distinguish solder pastes that provide consistency throughout the test period from those which do not. 5:10 PM Microstructure and Interfacial Characteristics of Electronic Interconnects of new viable eutectic alloy candidates for soldering applications, the applications, for soldering candidates alloy viable eutectic of new solution solid of Sn-rich on the formation based being TFB technique tailoring for options new metallurgical use of more can make joints is pure If the undercoating materials. interconnection low temperature occurs is pure Bi, the bonding alloy and the topcoating Sn or Sn-based 200 well below of Bi being the concentration dilute Sn[Bi] solid solution, essentially than near the middle of the joint higher in the originally somewhat a very strong Dissolved Bi has lead or substrate interfaces. component of Bi exceeds if the amount on Sn (/2/). However, hardening effect limit, about 3.5 wt-% at room temperature, significantly the solubility at the grain boundaries; at low supersaturation pure Bi will precipitate as globular particles while at the higher bismuth tends to precipitate precipitate discontinuously along the grain supersaturations it will case the reaction product has an embritteling boundaries. In the latter this work the mechanical behaviour of several effect on the joints. In have been studied, and respective material dilute Sn[Bi] solid solutions were assessed and implemented in a finite- models and parameters effect of the Bi distribution in the solder joint element program. The and the joining process parameters are modi- is analysed by the FEM The simulation results optimum reliability. fied accordingly to achieve which are conducted by shear tests with are verified by experiments real solder joints (/3/). 1. J.Kivilahti and dimensions similar to Density Interconnec- K.Kulojärvi, ‘A New Reliability Aspect of High Solders and Solder Inter- tions’, The Proc. of Design and Reliability of 9-13 February 1997, connections”, TMS Annual Meeting, Orlando, ´Deformation Reinikainen and J. Kivilahti, USA, pp. 377-384. 2. T. Metallurgical and Behaviour of Dilute SnBi(0.56at%) Solid Solutions´, T. 1999, pp. 123-132. 3. 30A, January, A, Vol. Materials Transactions ´A finite-element Reinikainen, M. Poech, M. Krumm and J. Kivilahti, in various shear tests and experimental analysis of stress distribution 120, March, 1998, ASME J. Elec. Pack., Vol. for solder joints´, Trans. pp. 106-113. 4:45 PM Invited RF Signal Integrity The Effect of Solder Paste Residues on Laura J. Turbini ; 1 Tommi Helsinki Daimler Shibaura 2 1 1 : Nokia Re- 1 ; ; 2 1 ; 2 Yoshiharu Kariya Yoshiharu : NEC Corporation, Mobile 2 ; Wayne Johnson ; Wayne ; Masahisa Otsuka 1 2 ; Jorma K. Kivilahti 2 Auburn University, 200 Broun Hall, Au- Auburn University, 2 ; John Evans 1 ; Yasunori Tanaka ; Yasunori 1 ; Roope Nikander 1 Ping Kwong Seto Ping Kwong : search Center, Nokia Grp., P.O. Box 407 FIN-00045 Finland; Box 407 FIN-00045 Nokia Grp., P.O. search Center, Institute of Technology, Dept. of Matls. Sci. and Eng., Shibaura 3-9- Institute of Technology, 1088548 Japan; 14, Minato-ku, Tokyo Kumiko Nakamura 224 Kanagawa Yokohama, Ikebe-cho 4035, Tsuzuki-ku, Comm. Div., Japan which are suitable for Packages of the area array mounting type and the production high-density mounting are receiving attention, packages is conse- volume of fine pitch BGA (ball grid array)-type sizes, characteristics quently increasing. With diminishing solder joint mechanical reliability of of interfacial microstructure which affect the electroless Recently, the joins are an issue that can not be neglected. of substrate or elec- Ni-P/Au plating has been used for surface finishes of fine pitch BGA. trode to meet a demand on mounting technology plating often exhibits However, BGA solder joint on electroless Ni-P reaction layers poor mechanical reliability because brittle interfacial Therefore, understanding which are formed during soldering process. the interfacial microstructure between solder and electroless Ni-P plating and its effect on the mechanical reliability is required in order to develop highly reliable solder joints. In this paper, the interfacial microstructure between Sn-Ag eutectic and electroless Ni-P plating has been characterized using SEM and TEM. The effect of interfacial microstructure on the mechanical reliability of actual CSP (chip size package) will also be presented. 4:25 PM Bonded Joints Mechanical Behaviour of Transfusion Box 3000, P.O. Lab. of Elect. Prod. Tech., University of Technology, TKK FIN-02015 Finland A recently introduced novel joining method-Transfusion Bonding (TFB)-allows fluxless Pb-free microjoining by utilising metallurgically compatible low melting point metals being bicoated chemically or it combines the benefits of inter- electrochemically (/1/). Essentially, metallic- and paste-free joining and bonding, and therefore it can be This type of joining used also for very fine-pitch electronics assembly. and bonding technique is becoming ever more important, when thinner diffusion barrier or adhesion layers, coated overlayers and especially smaller solder joint volumes are encountered in very high density electronic assemblies. Moreover, since there are only a limited number Chrysler Corporation, Huntsville Elect. Div., 100 Electronics Blvd., Huntsville Elect. Div., Chrysler Corporation, USA; Huntsville, AL 35824 burn, AL 36849 USA de- Grid Array (BGA) packages proliferate, the As the use of Ball and cost savings is driving automotive mand for packaging density form factor BGA to be used in the underhood electronics towards smaller to ensure the solder joint integrity of the BGA environment. In order compromised due to this miniaturization, components are not Electronics (DCHE) and Auburn Univer- DaimlerChrysler Huntsville the a study to use BGA underfill to achieve sity have embarked on use of underfill for flip chip has been demon- reliability goal. Since the in enhancing solder joint life. In this strated to be very effective feasibility of using un- DCHE is evaluating the multiple phases study, still meeting the aggres- derfill to extend the BGA solder joints while impact of various printed sive manufacturing cycle time. The reliability in thermal cycling circuit board (PCB) finishes and pad geometries ranging from 27mm to performance are also assessed. BGA packages 15mm body sizes are included in the study. 3:45 PM Break 4:00 PM Invited Reliability of Sn- Interfacial Microstructure and Mechanical Ni-P Film Ag Solder Joint on Electroless O. Reinikainen These in turn can affect the overall mechanical behavior of such behavior mechanical overall affect the in turn can These micro- and on solderability of reflow the effects In this study joints. sol- out with Sn-Ag carried studies were These were studied. structure Cu and Cu-Ni-Au using reinforcements, Cu or Ag or without ders, with made with carried out on joints properties were substrates. Mechanical using copper substrates. the same solders 3:25 PM Electron- Underhood Automotive Reliability for BGA Underfill ics

TUESDAY PM 109 Alberta T8L4K7 Canada 1 Dynatec Pressure AcidLeachingofZinc andCopperConcentratesby 3:30 PM cess willbedelineated. nally, theperceived economicsofthisuniqueindustriallyprovenpro- precious metalsfromchalcopyrite concentrateswillbediscussed.Fi- outlined. Inparticular,anovelmethodologyforeffectiverecovery of the systemanditsapplicationtochalcopyriteconcentrateswill be feasible processalternativeforthefuture.Inthispaper,history of leach systemtoproducecopperviaSX/EW. Thismayprovetobea ogy, utilized nitrogenspeciescatalyzationintheoxidizingpressure an overlookedbut,ironicallythefirstindustriallyprovenmethodol- proaches andseveraltechnologicalcandidateshaveemerged.Ofthese, sure oxidationofcopperconcentratesisonethemoreviable ap- new processingalternativesforproduction.Hydrometallurgicalpres- vailing inthecopperbusiness,thereisincreasedinterestevaluating Today, withastringenteconomicandenvironmentalclimatepre- LLC Bldg.,Butte,MT59701USA tana Tech., TheCtr. forAdv. Min.andMetallu.Process.,Rm.221, lyzed OxidativePressureLeaching The Treatment ofChalcopyritewithNitrogen SpeciesCata- 3:00 PM cussed. mechanisms ofchalcopyritedissolutionduringHPAL arebrieflydis- cated aninitialcopperprecipitation,followedbydissolution.Possible on theleachprocess.Kineticsamplingduringpressureindi- gangue materialsintheconcentrate,particularmagnesiumminerals using steady-staterecyclestreams,revealedthesignificantimpactof HPAL tobetechnicallyfeasible.Furtherbenchandpilotplanttests Mauritania. Initialbenchscaletestsonvariousconcentratesconfirmed various concentratesamplesfromtheGuelbMoghreindepositin alternative tosmeltingforchalcopyriteconcentrateswastestedon Thefeasibilityofapplyinghighpressureacidleaching(HPAL) asan 2 Concession St.,PostalBag4300,Lakefield,OntarioKOL-2110Canada; McKay (HPAL) ChalcopyriteFlotationConcentrates Chemistry andMechanismsofHighPressureAcidLeaching 2:30 PM USA Hoffmann, HoffmannandAssociates,Houston,TX77242 Saskatchewan, AlbertaT8L4K7Canada;JamesE. Session Chairs: March 14,2000 Tuesday PM & StolbergPartners,Duisburg47279Germany Associates, Houston,TX77242USA;NorbertL.Piret,Piret Program Organizers: Nickel, CobaltCommittee Sponsored by: Hydrometallurgy ofCopperandZinc Technology Applicationsinthe Cobalt andPreciousMetals:Pressure Hydrometallurgy ofCopper, Nickel, Pressure Technology Applicationsinthe date interfacialpropertiesofsolderalloys. characteristics andtheformationofintermetallicphasestoeluci- General GoldAustralia Dynatech Corporation, Metallu.Tech. Div., FortSaskatchewan, 1 ; I.Dymov : K.R.Buban Extraction &ProcessingDivision,Copper, 1 Gerry Bolton,DynatechCorporation,Fort ; D.Butcher 1 Location: OprylandConventionCenter Room: LincolnC ; James E.Hoffmann,Hoffmannand M. J.Collins 2 ; 1 Lakefield ResearchLimited,185 : 1 ; I.M.Masters Corby G.Anderson : C. J.Ferron 1 ; J.Stiksma 1 ; 1 Mon- 1 ; N. 1 ; for mixingoxygen,liquidandsolidtogether. this purpose.TheGLS-agitator(GLSgas,liquidandsolid)ispowerful oxygen andliquid.Outokumpuhasdevelopedanefficientagitatorfor point intheleachingistogetintocontactsolidcopperwith mud withthequickhydrochloricacidleachingprocess.Theimportant are treatedinthesilverelectrolysis.Goldisrecoveredfromgold tilting rotatingconverterwithoxy-fuelburner(TROF).Doréanodes with thegasroasting.Thedorésmeltinginfurnaceisdone copper isremovedwithpressureleaching.Seleniumroastingdone 000 mtin1998.Theanodeslimeamountisabout700-800mt. ThecapacityoftheOutokumpuPorirefineryistodayabout125 Box 103,Riihitontuntie,7E02200Espoo per AnodeSlime Outokumpu ProcessforthePreciousMetalRefiningfromCop- 4:45 PM from 15-35%.Afterautoclavinglessthan1%copperremains. the decopperizingprocess.Coppercontainedinrawslimeranges process chemistry, unitoperationsandprocessesassociatedwith Paso Refinery. Processequipmentwillbedescribed,alongwiththe sure leachingfordecopperizingofcopperrefineryslimesattheEl volve manydifferentprocesses.Thispaperdescribestheuseofpres- TheextractionofmetalsfromCopperRefinerySlimesmayin- El Paso,TX79915USA Wesstrom Pressure LeachingofCopperRefinerySlimes 4:15 PM 4:00 PMBreak in thedevelopmentofanewcopperpressureleachprocess. studies, andhowtheexperiencegainedinthesestudieshasbeenutilized sure leachingthathavebeenidentifiedthroughprocessdevelopment sure leaching.Thispaperhighlightsrecentimprovementsinzincpres- additional zincconcentrateshavebeenshowntobeamenablepres- studies carriedoutintheDynateclabFortSaskatchewan,dozensof has beencommercializedatfourseparatelocationstodate.Inpilot direct leachingofconcentratewithspentelectrolyteinanautoclave, commercially fornearlytwodecades.Theprocess,whichincludes Pressureleachingofzincsulphideconcentrateshasbeenpracticed Problems, RussianAcad.ofSci., Ufa450001Russia; Senkov Shagiev Mechanical PropertiesofaTiAl IntermetallicAlloy Effect ofGrainSizeandStrainRateonRoomTemperature 2:00 PM ID 83844-3026USA;IsaacWeiss, JohnsonMatthey, USA Session Chairs: March 14,2000 Tuesday PM Yu, RMICorporation,R&D,Niles,OH44446-0269USA USA; IsaacWeiss, JohnsonMatthey, USA;KuangOscar Idaho, IMAP-MinesBldg.#321,Moscow, ID 83844-3026 Albany, OR97321USA;F. H.(Sam)Froes, Universityof Program Organizers: Shaping andFormingCommittee Division, StructuralMaterialsTitaniumCommittee, Sponsored by: Its Alloys:SessionII Production &ProcessingofTitanium Process SynthesisandModelingforthe 2 1 ; F. H.(Sam)Froes ; A.V. Kuznetsov 1 ; 1 Phelps DodgeRefiningCorporation,6999N.LoopRd., Materials ProcessingandManufacturing : Sam Froes,UniversityofIdaho,Moscow, Olli Jarvinen Location: OprylandConventionCenter Room: KnoxvilleB James A.Hall,Oremet-Wah Chang, 1 ; G. A.Salishchev 2 ; 1 Institute forMetalsSuperplasticity 1 ; 1 Outokumpu Wenmec Oy,P.O. 1 ; R.M.Imayev : 2 University of Bradford C. : M.R. 1 ; O.N.

TUESDAY PM 110 ; ; 1 1 metastable β ; Krishna + 1 ADMA Prod- 2 primary δ ; O. N. Senkov 2 ) phase is stable-no ; Oleg N. Senkov 1 β retained β Henry J. Rack ” + University of Idaho, IMAP, : 1 δ University of Idaho, Instit. for C followed by rapid cooling a C followed by rapid cooling ; 1 2 ° + ( ; 1 C and above. ; N. K. Gabdullin ° 2 primary Javaid I. Qazi δ m, and, at the smaller grain size, an ) : µ retained β ’, is formed. However at temperatures between ’, is formed. However ’ + δ R. M. Imayev m to 0.1 δ µ : + ( ; F. H. (Sam) Froes ; F. ; Valadimir S. Moxson ; Valadimir 2 C but had no influence on ductility at higher tempera- 1 ° C, rapid cooling results in the formation of orthorombic, C, rapid cooling results C using tension and compression testing. The ductility of C using tension and compression testing. The primary ° ° δ Clemson University, Cer. and Matls. Eng., 110 Olin Hall, 110 and Matls. Eng., Cer. Clemson University, ’ 1 δ ; Institute for Metals Superplasticity Problems, Russian Acad. of Institute for Metals Superplasticity Problems, 1 2 ”. Finally below this temperature region the ”. Finally below this Matls. and Adv. Process., 321 Mines Bldg., Moscow, ID 83844-3026 Moscow, Process., 321 Mines Bldg., Matls. and Adv. USA; Sci., Ufa 450001 Russia on ductility and flow The effect of grain size and partial disordering in the temperature range stress of an intermetallic Ti3Al was studied of 20 to 800 when the grain size the fully ordered material increased considerably decreased from 27 elongation of 4.8% was achieved at room temperature. Partial disordering of the crystal lattice led to a decrease in ductility at temperatures below 500 tures. The critical grain size at which a brittle-to-ductile transition occurred in the fully ordered material was determined for each temperature studied. This critical grain size increased as the temperature increased. Dislocation slip changed from a localized planar mode to a more uniform fine slip, the slip line spacing decreased, cross-slip developed, and relaxation capability of grain boundaries enhanced when the grain size decreased below the critical value. The fracture mode changed from a brittle transcrystalline mode to a brittle intercrystalline to a ductile mode when the grain size decreased and mode and, finally, temperature increased. Transcrystalline fracture was observed in specimens with grain sizes above the critical grain size, while intercrystalline and ductile fracture modes occurred in specimens with grain sizes below the critical grain size. Specimens with submicron sized grains exhibited features of superplastic flow at 600 3:15 PM Break 3:15 PM PM 3:30 on Marten- Temperature Treatment Solution of The Influence in IMI 550 Transformations sitic Phase Kharia 29670-0907 USA Clemson, SC the martensi- temperature on of solution treatment The influence in IMI 550(Ti-4Al-4Mo-2Sn-0.5Si) observed tic phase transformations samples is treated of equilibrated When solution has been investigated. of above 960 conducted at temperatures hexagonal martensite, 850 and 960 δ occurring on rapid cooling. This transi- martensitic transformation tion from by treatment temperature will be discussed with decreasing solution of solution treatment temperature on alloy considering the effect as of this partitioning on phase stability partitioning and the influence tem- transmission electron microscopy and elevated revealed by x-ray, perature neutron diffraction. 3:55 PM a Gamma-TiAl Sheet Produced from Characterization of Blended Elemental Powders Francis H. Froes USA; ID 83844-3026 Mines Bldg. Rm. # 321, Moscow, OH USA Twinsburg, ucts Inc., 8180 Boyle Park Way, composition of Ti- Gamma titanium aluminide sheet of a nominal elemental powder. 46.5Al-2Cr-3Nb-0.2W was produced from blended with hot rolling at tem- A novel loose sintering approach combined The sheet was char- peratures near alpha-transus temperature was used. and TEM. A acterized using X-ray diffraction, optical microscopy a colony size of around fully lamellar structure was produced with gamma-TiAl and about 100mm. The material consisted of two phases: 2%. Mechanical proper- 20% of Ti3Al. The porosity level was about ties of the sheet were also studied. 4:20 PM of Grain Size and Ductility of a Ti3Al Intermetallic: Effect Partial Disordering G. A. Salishchev ; 2 m to µ C and ° Clemson 1 ; 1 University of 1 C. Tensile me- C. Tensile ° ; ; M. R. Shagiev 1 2 C to 600-900 ° , that is the dependence was , that is the dependence ; C. R. Robinson 1 0.5 ; V. M. Imayev ; V. m. The increased ductility was m. The increased 2 µ ; F. H. (Sam) Froes ; F. 1 =0.4 MPa m y Henry J. Rack Institute for Metals Superplasticity Problems, 2 : ; G. A. Salishchev 2 ; O. N. Senkov C followed by annealing at 770-990 C followed 2 ° m led however to considerable decrease in ductility. The decrease in ductility. m led however to considerable and grain size of 8 and grain µ -1 R. M. Imayev m were produced by an isothermal forging in the temperature in the forging by an isothermal produced m were : µ the strain rate range was substantially extended towards the higher strain rates. The effects of composition, superlattices type, and grain size on low-temperature superplastic properties of titanium aluminides was investigated. An increase in the volume fraction of the Ti3Al phase in TiAl based alloys led to improvements in the superplastic properties such as ductility and strain rate sensitivity and more homogeneous deformation. The activation energies of superplastic flow were determined to be close to the activation energy of grain boundary diffusion. The considerable decrease in superplastic forming temperatures opens possibilities in cost reduction by using less expensive tools and deformation processes. Russian Acad. of Sci., Ufa 450001 Russia The data on superplastic behavior of TiAl and Ti3Al intermetallic alloys with a high ordering energy and submicron grain size are summarized. By decreasing grain size from 10 ìm to 0.1 ìm, the superplastic temperatures were decreased from 1000-1200 Idaho, Instit. for Matls. and Adv. Process., 321 Mines Bldg., Moscow, Idaho, Instit. for Matls. and Adv. ID 83844-3026 USA; chanical properties of the specimens were determined at room tem- were determined of the specimens chanical properties were ana- and after deformation microstructures before perature and a strain rate 6.9% was achieved at TEM. Peak ductility of lyzed using s around 0.1 N. K. Gabdullin yield stress versus grain size followed the Hall-Petch relation with the size followed the Hall-Petch relation with yield stress versus grain k Hall-Petch parameter accompanied with development of single-system deformation twins. single-system deformation with development of accompanied twinning in specimens with larger grain sizes Activation of multiple twin development in specimens with the grain and suppression of the size below 1 as compared to the coarse-grained material. about 5 times weaker 2:25 PM Strain Deformation of Coarse-Grained High High Temperature, Beta-CEZ Titanium 29670- Olin Hall, Clemson, SC Eng., 110 and Matls. Cer. University, 0907 USA high strain deformation behavior of coarse The high temperature, grained Widmanstatten Beta CEZ (Ti-4.8Al-2Sn-3.8Zr-3.8Mo-1.9Cr- strain rates of 1 to 2x10- 1Fe-0.045O) has been investigated between Under these condi- 4 s-1 at temperatures between 1013 and 1138K. exhibited an initial maxi- tions the compressive stress-strain response strain. At the lowest mum followed by flow softening with increasing this flow softening temperatures and highest strain rates examined examined by strain hard- behavior was followed at the highest strains stable flow and there- ening. Dynamic material modeling indicated that expected above strain fore optimal deformation conditions can be 1025 and 1100K. This rates of 10-2 s-1 at temperatures between this stable flow regime presentation will discuss how establishment of associated deformation, involves a balance between grain boundary of the grain bound- resolution of the phase, dynamic spheroidization of lamellae ary and lamellae, dynamic recovery and recrystallization associated with dynamic and dynamic grain growth. Stable flow was and phases, while recovery and recrystallization of the constituent 1013K, was associ- unstable flow at the lowest temperature examined, formation at/interfaces, ated with shearing of grain boundary and void the later at the lower the former predominating at high strain rates, temperature void strain rates examined. With increasing deformation flow within the formation was progressively replaced by localized spheroidization, dissolu- grain boundary region incorporating dynamic of the phase. Finally tion of the phase and dynamic recrystallization flow was associ- at the highest temperatures and strain rates, unstable the lamellae within the ated with flow localization and kinking of near-grain boundary region. 2:50 PM Based Al- and Ti3Al Superplasticity of TiAl Low-Temperature loys Idaho, Instit. for Matls. and Adv. Process., 321 Mines Bldg., Moscow, Bldg., 321 Mines Process., Adv. Matls. and Instit. for Idaho, USA ID 83844-3026 from 0.4 sizes varying with grain alloy samples TiAl Gamma 17 range 800-1000

TUESDAY PM 111 contrasting particle spatialdistributions,following theapproachof two differentPM-processed SiC-reinforced7093Al materialswith ture toughnesspredictionsareobtained fromthemicrostructuresof selected crackpathmetrics.Using crackpropagationsimulations,frac- show strongcorrelationsbetween the degreeofparticleclusteringand ential pathsforcrackpropagation inclusteredmicrostructures,and Cellular automata-basedcrackpropagation simulationsrevealprefer- experimentally obtainedandartificially simulatedmicrostructures. defined, usingfractalgeometrytechniques.Resultsaregivenboth for nomena. Theanalysisallowsmulti-scaleclusteringparametersto be tential damagesitesisdiscussedintermsofcrackpropagationphe- inter-particle proximity. Theimportanceoftheconnectivitypo- whereby theinter-particleconnectivityisgivenpriorityover ticles. Inthispaper,newcharacterizationtechniquesaredemonstrated limited informationaboutthespatialarrangementsofindividualpar- Distribution Functions(RDF’s) ortessellationschemes,revealonly particle-particle spacings.Theseapproaches,basedeitheronRadial microstructures haveconcentratedonthestatisticsof Previous attemptstocharacterizeparticledistributionsincomposite aspect ofthecompositemicrostructurehasreceivedlittleattention. arrangements ofthereinforcingparticles.However,untilrecentlythis discontinuously-reinforced metallicmatrixcompositesandthespatial strong correlationbetweenthefracturetoughnessof Previousexperimentalandtheoreticalworkhasshownthatthereis Wright-Patterson AFB,OH45433USA ratory, Matls.Direct.,AFRL/MLLMBldg.655,2230Tenth St.,Ste.1, structures New DirectionsintheCharacterizationofCompositeMicro- 2:30 PM for theseapplicationswillbeprovidedanddiscussed. research thatwillberequiredtosupportthedevelopmentofMMC’s applications intheaerospaceindustrywillbeprovided.Suggestionsfor sive metalstechnology. Theresultsofarecentanalysispotential ability areexpectedfrommorewidespreadapplicationofthisperva- matic additionalbenefitsinaffordability, performanceandsupport- automotive, electronicsandrecreationproductsectors.However,dra- lished inthemilitaryandcommercialaerospaceindustry, aswell discontinuously-reinforced MMC’s. Significantmarketsarenowestab- the understanding,development,processingandimplementationof Agreatdealofprogresshasbeenmadeinthepastthreedecades 7817 USA and Manu.Direct.,2230Tenth St.,Wright-Patterson AFB,OH45433- Daniel B.Miracle Directions forResearchinDiscontinuously-ReinforcedMMC’s 2:00 PMInvited Lab., Wright PattersonAFB,OH45433USA 44106 USA;BenjiMaruyama,USAirForce,ForceRsch. Reserve University, Matls.Sci.andEng.,Cleveland,OH Session Chairs: Room:BayouA March 14,2000 PM Tuesday USA Aluminum ConsultantsGroupInc.,Murrysville,PA 15668 Engineering, Cleveland,OH44106USA;Warren H.Hunt, Reserve University, DepartmentofMaterialsScienceand Program Organizers: Committee; Young LeadersCommittee Sponsored by: Directions inMMCResearch Metal MatrixComposites:New Research andDevelopmentEffortson : Jonathan EdwardSpowart 1 Joint ASM-MSCTS/TMS-SMDComposites ; BenjiMaruyama John J.Lewandowski,CaseWestern Location: OprylandConventionCenter John J.Lewandowski,CaseWestern 1 ; 1 AF ResearchLaboratory, Matls. 1 ; 1 Air ForceResearchLabo- : Formed byChemicalPartitioning In-Situ DuctileMetal/BulkMetallicGlassMatrixComposites 3:10 PM to besignificantlylowerthanthatpresentedintheliterature. gram hasbeenreexamined.Theperitectictemperaturefound addition, thealuminumrichregionofboronphasedia- cooled dramaticallyaffectstheaspectratioofresultingAlB2.In has beenfoundthattherateatwhichaliquidaluminumboronalloyis the growthofAlB2inliquidaluminumhasbeenextensivelystudied.It AlB2 intheabsenceofAlB12andotherborides.Aspartthiseffort cost synthesisroutesthatwillallowpreparationofhighaspectratio material. Currentdevelopmenteffortsarefocusedonelucidatinglow tions usingalaboratoryscaledynamometersuggestpromiseforthis ties arerequired.Mechanicaltestingandsimulationofbrakingcondi- a combinationofexcellentwearresistanceandhighspecificproper- cations includeautomotivebrakerotorsandturbinecomponentswhere making thiscompositealowcostmaterial(~$5.00/kg).Target appli- In situpreparationoftheAlB2reinforcementsimplifiesprocessing which AlB2flakesthatarepreparedinsituactasthestiffeningphase. new materialisadiscontinuouslyreinforcedaluminumcompositein diboride flakes(diameter/thickness>100)hasbeendeveloped.This Anewmetalmatrixcompositebasedonhighaspectratioaluminum Sci. andEng.,1304W. GreenSt.,Urbana, IL61801USA MMC Development ofaNewDiscontinuouslyReinforcedAluminum 2:50 PM materials. and theexperimentally-obtainedfracturetoughnessvaluesforthese Rice andJohnson.Thereisgoodagreementbetweenthepredictions 18, Roma00184 Italy; 1 Fibers Metal MatrixCompositesBased onAluminumandOptical 3:40 PM 3:30 PMBreak Ti-Cu-Ni-Be system. matrix compositebasedonbulkglassformingcompositesinthe Zr- results arepresentedforaductilemetalreinforcedbulkmetallicglass ticles. X-raydiffraction,microstructural,andmechanicalproperty and forthepropagationofshearbandsthroughbeta-phasepar- cally homogeneous.Thiscleaninterfaceallowsforstabledeformation ductile metalbeta-phaseandthebulkmetallicglassmatrixischemi- to theimprovedbehaviorisqualityofinterfacebetween the large plasticstrainstofailureontheorderof8%.Anotherkeyfactor values of~4%.Specimenstestedundercompressiveloadingexhibit matrix alone.Bendtesthaveshownlargeplasticstraintofailure ness numbersthatare250%greaterthanofthebulkmetallicglass this newcompositematerialhavedemonstratedCharpyimpacttough- mechanical loading.Sub-standardCharpyspecimenspreparedfrom glass matrixthatleadstothegenerationofmultipleshearbandsunder particles imposeintrinsicgeometricalconstraintsonthebulkmetallic chemical compositionandprocessingconditions.Theseductilemetal phology withaparticlesizeandperiodicitythatisdeterminedbythe from theliquidstate.Thecrystallinebeta-phasehasadendriticmor- ite (ductilemetalinabulkmetallicglassmatrix)isobtainedoncooling cal compositionandprocessingconditionsastabletwo-phasecompos- extends thecompositestraintofailure.Specially, bycontrolofchemi- metallic glassmatrix;thisstabilizescrackgrowthinthematrixand constraint thatallowsforthegenerationofmultipleshearbandsin tion ofaductilemetalphaseintometallicglassmatrixyields trix viain-situprocessing;i.e.chemicalpartitioning.Theincorpora- of ductilemetalreinforcedcompositeswithabulkmetallicglassma- glass formingabilityofbulkmetallicglassesallowsforthepreparation improved toughnessandlargeplasticstraintofailure.Theremarkable mechanical properties.Thisnewlydesignedmaterialexhibitsboth composite materialhavebeenpreparedthatdemonstrateimproved Anewclassofductilemetalreinforcedbulkmetallicglassmatrix 91125 USA Matl. Sci.,W.M. KeckLab.ofEng.,MailStop138-78,Pasadena,CA C. Hays University ofRome “LaSapienza”,Dept.ICMMPM, Via Eudossiana : : 1 Aaron C.Hall Ferdinando Felli ; William L.Johnson 1 ; 2 1 University ofRome”La Sapienza”,Dept. 1 ; AntonioPaolozzi The UniversityofIllinois,Dept.Matls. 1 ; 1 California InstituteofTechnology, : Choongnyun PaulKim 2 ; MicheleA.Caponero 1 ; Chuck 3 ;

TUESDAY PM 112 ; 1 Kent 1 ; 1 Herve Deve : 3M, Met. Matrix 1 ; 1 Julia E. Fulghum : ; S. R. Holloway 1 Sudipta Seal, University of Central Room: Canal B Location: Opryland Convention Center D. L. Cocke, Lamar University, Gill Chair of D. L. Cocke, Lamar University, Materials Processing and Manufacturing ; J. P. Sorensen ; J. P. 1 2:00 PM Invited High Energy and Spatial Resolution XPS Analysis of Surface- Modified and Heterogeneous Polymers Surface Engineering in Materials Science I: Coating/Films Characterization (C)-II Sponsored by: Chem. Dept., Kent, OH 44242 USA State University, Surface analysis of polymers has historically been viewed as being XPS is particularly both of particular interest and of special difficulty. useful in the analysis of polymers since chemical information can be Metal matrix in-situ particle composites are being developed in being developed are composites in-situ particle matrix Metal stable thermodynamically of producing the objective years with recent clean interface matrix having in the reinforcements fine particulate been attempts have work, In the present products. reaction free from in-situ com- particle reinforced Al matrix MgAl2O4 made to produce To Mg alloy. particles in an Al-2 of reactive oxide posites by addition to 2 wt% of composites, up in-situ particle prepare Al-MgAl2O4 into Al-2 Mg were incorporated and TiO2 particles Fe2O3, Cr2O3 formed in and MgO particles vortex method. MgAl2O4 alloy melt by and the the oxide particles by reaction between all the composites the pure Fe, Cr and Mg2Ti2O5 also formed in alloy melt. In addition, The reaction between the oxide particles and respective composites. the nearly complete. The microhardness of Al-2 Mg alloy melt were to dissolution of the reduced elements such composites improved due a extent. The reduction in microhardness in as Fe, Cr etc. to limited with the presence of porosity and deple- few composites is associated Additional factor to increase the hardness tion of Mg from the matrix. dispersion of MgAl2O4 and MgO particles. of the composites is the the poor tensile strength, except where Porosity resulted in improved. Elongation % is higher microhardness was substantially to alloy for all the composites probably due than that of the base the the matrix and presence of microporosity in depletion of Mg from structure. 5:00 PM at 3M Continuous Fiber Metal Matrix Composites L. Anderson T. MN 55144-1000 USA Comp., 3M Center Bldg. 60-1N-01, St. Paul, matrix composites will 3M R&D efforts on continuous fiber metal aluminum/alumina fiber be reviewed. In particular, the development of lines will be composites wires for high voltage power transmission discussed. Division, Surface Engineering Committee Program Organizers: and Analysis Florida, Advanced Materials Processing Aerospace Engineer- Center and Mechanical, Materials and B. Dahotre, Univer- ing, Orlando, FL 32816 USA; Narendra Space Institute, Center for Laser Applica- sity of Tennessee Mishra, tions, Tullahoma, TN 37388 USA; Brajendra Colorado School of Mines, Kroll Institute for Extractive Metals, Golden, CO 80401-1887 USA; John Moore, Colo- rado School of Mines, Department of Metallurgy and Materials Engineering, Golden, CO 80401 USA Tuesday PM March 14, 2000 Session Chairs: Chem. and Chem. Eng., Beaumont, TX 77710 USA; L. J. Instit. Maksymowicz, University of Mining and Metallurgy, of Elect., Kraków 30-059 Poland ; 2 United 1 ; P. N. P. ; 1 ; ; S. Sakai 1 2 Enea Frascati Enea 3 Furukawa Electric 2 ; K. Mihara 1 ; V. C. Nardone ; V. 1 ; S. C. Panigrahi 1 Hirowo G. Suzuki ; J. T. Beals ; J. T. 1 P. C. Maity P. : : Sumitomo Metal Industries Limited 3 National Institute of Foundry and Forge Technology, National Institute of Foundry and Forge 1 National Institute for Metals Japan; 1 ; 1 ; 3 Shihong Gary Song : P.O. Hatia, Ranchi 834003 India P.O. Chakraborty Company Limited; conductive Cu based Development of high strength high electrical electric and electronic in-situ composites is potentially useful in the obtain high strength and industries. Microstructure control is useful to the effects alloy, Based on the Cu-15wt%Cr binary high conductivity. of microalloying elements such as Zr, Fe and Sn were examined. Pro- cessing involves ingot making by induction heat melting, hot stage forging, solution treatment, cold rolling and aging. Heavy cold rolling is effective to refine the lamellar spacing of second phase (Cr fiber) and aging treatment gives precipitation strengthening and recovery of in the cop- Dynamic recrystallization occurs electrical conductivity. per matrix during heavy cold rolling more than h=5.0 (here, h=lnA0/ while banded structure is formed and A) in a Cu-15wt%Cr binary alloy, higher strength is attained in the Cu-15wt%Cr-0.2wt%Zr alloys, indi- Age hardening is remarkable in this of recovery. cating the difficulty alloy due to the acceleration of Cr precipitation. The addition of 0.2 to 0.5wt% of Fe does show work softening. Fe is scavenged to the second phase of Cr during solidification. The effect of Sn is similar to that of Zr although the electrical conductivity drops more than the The tensile strength follows Hall-Petch type equation with case of Zr. Cr phase becomes quite ductile in the Cu matrix. lamellar spacing of Cr. In the conference, the microstructure control is emphasized to optimize the strength as well as electrical conductivity. 4:40 PM Preparation and Mechanical Properties of Al-MgAl2O4 In-Situ Particle Composites Technologies Research Center, 411 Silver Ln., Hartford, CT 06108 411 Center, Research Technologies USA for their ultra light- Aluminum-beryllium composites are known and have found broad weight and exceptionally high specific stiffness in aerospace indus- applications as static and low-stress components recently been seen for An increasing interest in the alloys has try. applications for aircraft dynamic, high-temperature, and high-stress an apparent scarcity in and engine components. However, there is in particular, the sec- literature of the property data of these alloys, fatigue, and fracture ondary mechanical property data such as creep, the time dependent toughness. The present investigation concerns temperatures of a com- deformation and rupture behavior at elevated 162”. The creep and mercial aluminum-beryllium alloy “AlBemet and discussed in stress rupture properties of the alloy were measured reinforced Al matrix comparison with that of ceramic particulate were conducted and ana- composites. Fractography of the specimens and stress rupture proper- lyzed in connection with the measured creep ties. 4:20 PM High Conductive Cu Microstructure Control of High Strength Based In-Situ Composites K. Adachi Aerospaziale, Via Eudossiana 18, Roma 00184 Italy; 00184 Italy; 18, Roma Eudossiana Via Aerospaziale, 00044 Italy Roma 46, Frascati, Enrico Fermi Via Center, Research promis a very components into structural fiber optical Embedding inter- Recently the health monitoring. for real time technology ising in the me- sensor is increased low cost and reliable est for producing Aluminum and community. and aerospace engineering chanical, civil embedded in been successfully optical fibers have polyimide coated tech- both cast and colamination alloys by using different aluminum tests: been subjected to the following studied samples have niques. The optical the structural integrity; tests in order to verify mechanical the fiber integrity after embedding pro- transmission tests to highlight of the fiber-matrix interface; inter- cess; metallographic observation to verify that the embedded optical fiber can ferometric tests in order sensor for measuring variation of the physi- be usefully used as a global material. The possibility of embedding cal properties of the hosting alloys has been demonstrated. The obtained optical fibers in aluminum show interesting performances. aluminum composites 4:00 PM Behavior of Be/Al Composite Mate- Creep and Stress Rupture rials

TUESDAY PM 113 Films Gas AdsoptiononHighlyDiffusingSurfacesof(Sn,Ti)O2Thin 3:10 PM correlates withahighersheetresistance. significantly lowerextinctioncoefficientofthesputter-depositedfilms resistance measurementsverifythatthisisthecase.Specifically, the ent methodswillnotbethesameandx-raydiffractionsheet constants suggestthatthemicrostructureoffilmsfromtwodiffer- deposited byasimplesputterdepositionmethod.Theresultingoptical we determinethedensityofplatinumdepositedbyevaporationand measuring thicknesswiththesemethodsandweight-gain, ness ofeachtwometalsinabi-metalicstackisdiscussed.Finally, by the opticalconstantsformaterial.Thedeterminationofthick- We discusstheconditionswherethisispossibleandhowtodetermine films, withemphasisonspectroscopicellipsometryandtransmission. Opticalmethodsareusedtodeterminethethicknessofthinmetal Rsch. Labs.,Tempe, AZ85224USA strate temperature aslongtheinitialstateis metallic. Thelight that veryroughsamples couldbeobtainedindependently ofthesub- melting pointofdepositedmetalor alloy. In thepresentworkweshow feature ofthistechniqueisthesubstrate temperaturehigherthanthe to beefficientforquiteanumber ofoxidecompounds[2].Thekey known asRGTO(rheotaxialgrowth andthermaloxidation)hasproved in formationofhighlydiffusingsurfaces of(Sn,Ti)O2.Thismethod the post-depositionoxidationofpreviously grownmetalfilmsresults nealing enhancesthesurfaceroughnessonlytosomeextent.However, presence ofoxygen,havesmoothsurfaces.Thepost-deposition an- In general,thinoxidefilmsgrowninthereactiveprocess,i.e. the creation oflargesurface-to-volumeratioseemstosolvethisproblem. such asanappropriatedopingorincorporationofcatalysts,asimple centers activeforgasadsorption.Despiteaquitewellknownmethod its sensitivity, canbegreatlyimprovedbyincreasingthedensityof candidates forgassensingdevices.Thesensorperformance,especially prepared byrfreactivesputteringfrommetallictargetsarepromising Recently, ithasbeendemonstrated[1]that(Sn,Ti)O2 thinfilms Metallurgy, Al.Mickiewicza30,Cracow30-059Poland Harland G.Tompkins Spectroscopic EllipsometryMeasurementsofThinMetalFilms 2:45 PMInvited ity ofmetalcontaminationdeviceregions. analysis ofmetalprecipitatestabilityinsiliconanddiscussthefeasibil- tion ofthermaltreatment.Basedonourresults,wepresenttheoretical studied thedissolutionrateofmetalprecipitatesinsiliconasafunc- Furthermore, withx-rayfluorescencemicroscopy(m-XRF),wehave state ofsub-micronscaleCuandFeimpurityprecipitatesinsilicon. tion spectromicroscopy(m-XAS),wehavecharacterizedthechemical growth-related defectsinthebulkofmaterial.Withx-rayabsorp- region ofintegratedcircuitsbyuseoxygenprecipitatesandtheir the abilitytoretainmetalimpuritiesawayfromactivedevice Metalimpurityprecipitatesinsiliconwerestudiedwithafocuson Ctr., MailStop2-400,Berkeley, CA94720USA McHugo Precipitates inSiliconUsingSynchrotron-BasedX-Rays Elemental andChemicalIdentificationofSub-MicronMetal 2:25 PM and 3M. has beenpartiallysupportedbyNSF(DMR89-20147),DowChemical in correlationwithimagingFTIRandphase-contrastAFM.Thiswork blend sampleswillbedemonstratedusingsmallareaandimagingXPS surface modifications.Lateralandverticalheterogeneitiesinpolymer valence bandphotoelectronspectrawillbeusedintheevaluationof ods toenhanceXPSsensitivitywillalsobediscussed.Bothcoreand analysis ofcomplexpolymersurfaces.Theusederivatizationmeth- resolved, smallarea,andimagingphotoelectronspectroscopyforthe ever-decreasing featuresizes.Thistalkwillfocusontheuseofangle- demands foranalysisofmulticomponentormultilayeredsampleswith plexity. Alongwiththesedevelopments,however, comeincreasing acquire interpretablechemicaldatafromsamplesofincreasingcom- opments inXPSinstrumentationhaveenhancedtheanalystsabilityto acquired, frequentlywithminimaldamagetothesample.Recentdevel- : 1 M. Radecka ; 1 Lawrence BerkeleyNationalLaboratory, Adv. LightSource 1 1 ; K.Zakrzewska ; 1 Motorola Inc.,Labs.,PhysicalSci. 1 ; 1 University ofMiningand : Scott : Deposition from theVapor Phase Construction ofaNewC-H-OTernary DiagramforDiamond 4:00 PM order of102Ohmin80%RHand(3)stabilityreproducibility. ment whichchangesfromtheorderof105Ohmin30%RHto processing, (2)humiditysensitivitybymeansofresistancemeasure- method includinghowtodecreaseafilmresistancebyusingsurface conduction carrier. Iwillreportinthepaper about(1)fabrication not onlypreventthosetroublesbutalsohaveafunctiontoproduce resistivity anditshygroscopicswelling.Metaloxidesabovementioned is notdesirabletouseitasahygrometerbyitselfbecauseofitshigh tics. Compoundzeoliteitselfexhibitshumiditycharacteristics.But,it Fe2O3 fabricatedbyevaporation,exhibitagoodhumiditycharacteris- compound zeoliteandmetaloxidethinfilmssuchasNiO,CuO quickly inthehumidityatmosphere.Itwasfoundthatmixtureof ducible thinfilmhumiditysensorofwhichresistancecanrespond Itisearnestlydemandedforproducingsensitive,stableandrepro- Higashi-Osaka, Osaka577-8502Japan Jun-ichi Kodama Humidity CharacteristicsofThinMetalOxide-ZeoliteFilms 3:40 PM 3:30 PMBreak films (RGTO technique),Semicon.Sci.Technol. 5(1990)1231. A. Camanzi,AnewtechniqueforgrowinglargesurfaceareaSnO2thin 47(1998) 194.[2]G.Sberveglieri,Faglia,S.Groppelli,P. Nelliand SnO2-TiO2 solidsolutionsforgassensors,SensorsandActuatorsB gas adsorptionprocesses.[1]M.Radecka,K.Zakrzewska,Rekas, tivity measurementsinchanginggasatmosphereswereusedtostudy SEM andthelevelofdiffusedreflectionlight.Electricalresis- correlation wasfoundbetweenthefilmmorphologyasdeterminedby ranges wereperformedinordertostudythesurfacedevelopment.The scattering experimentsintheultraviolet,visibleandnear-infrared penetration kinetics forseveralcasesofpractical interest, suchas,a specific constants. Thisrelationshipisusedinananalysis forcapillary and equilibriumvaluesofthecontact angle,andBAaresystem form: q(t)=q0+exp(B-At), where q(t)andq0areinstantaneous reactive couplesiscompatiblewith anempiricalrelationshipofthe spreading problems.Itisshownthat complexflowbehaviorofseveral models provideamoreconvenient approachtoanalyzepractical regimes thatarelimitedbyinterfacial reactionsordiffusion,empirical proach couldallowforidentificationbyexclusionofcomplexflow for simpleliquids.Itissuggestedthatwhilesuchapresentational ap- versus ln(time)thatareformallyconsistentwiththeclassicalmodels are revisitedtoidentifyflowregimesfromplotsofln(dropletradius) Thespreadingkineticsinselectedhigh-temperaturereactivecouples Pgm., Menomonie,WI54751USA Couples An AnalysisforCapillaryPenetrationKineticsinReactive 4:20 PM Lydtin, DiamondandRelatedMaterials,1,1(1991). lowship (SallyEaton).Reference:1.P.K. Bachmann,D.LeersandH. 9876251 andfromKYNASA-EPSCoRprogramthroughKSGCfel- Financial supportcamefromNSFthroughCAREERaward#CTS analyzing thediamonddepositionfromvaporphaseinsidetrenches. Furthermore, thenewternarydiagramisshowntobeusefulwhen ture andpressureonthisnewternarydiagramarealsoexplained. monoxide (CO)istreatedasaneutralspecies.Theeffectsoftempera- diagram basedonradicalspeciescompositionworksonlywhencarbon non-typical feedgasmixtures.Theanalysisalsoshowsthattherevised and helpsexplainthecontradictingexperimentaldatapointswith that theradicalspeciescompositiondodistinguishthreeregions compositions. Theanalysisofthecomputationaldomainindicates original C-H-OternarydiagrambyBachmannet.al.1basedonfeedgas phase andgas-surfacechemistryforthedatapointspresentedin This constructionisbasedonthesteadystatecomputationsofgas tion, non-diamonddepositionandnofromthevaporphase. is constructedthatdistinguishesdifferentregionsfordiamonddeposi- AnewC-H-Oternarydiagrambasedonradicalspeciescomposition KY 40292USA Eaton 1 ; : 1 University ofLouisville,Dept.Chem.Eng., R. Asthana 1 ; 1 Kinki University, Elect. Dept.,3-4-1Kowakae, 1 ; 1 University ofWisconsin-Stout,Manu.Eng. : Mahendra K.Sunkara 1 ; SallyC. :

TUESDAY PM 114 Uni- 2 Kyushu 1 ; ; David E. 2 1 University of 1 ; 2 ; Yuji Kimura ; Yuji 1 Wayne C. Chen Wayne University of Idaho, 3450 S. of Idaho, University 3 : ; Huahang Tian 1 Dynamic Systems Inc., 323 Route 355, Dynamic Systems Inc., 1 National Research Institute for Metals, Setsuo Takaki 2 ; 1 : Michael Atzmon : ; Hugo S. Ferguson 1 versity of Michigan, Dept. of Matls. Sci. and Eng., Ann Arbor, MI 48109-2136 USA present a study of the evolution of grain size and strain in Fe We powder during low-energy ball milling. For this method of inducing mechanical attrition, local heating by impact is negligible, so that the temperature and milling intensity can be controlled independently. method, the grain size and RMS strain Using the Warren-Averbach were determined as a function of milling time for temperatures be- grain tween 298K and 523K and varying milling amplitudes. Average diameters as small as 7 nm were observed. A model was developed to describe the evolution of the grain size, based on a rate equation which includes grain refinement and simultaneous grain growth. The contri- University, Dept. of Matls. Sci. and Eng., 6-10-1 Hakozaki, Higashi- University, ku, Fukuoka 812-8581 Japan; Ibaraki 305-0047 Japan 1-2-1 Sengen, Tsukuba, is a useful technique for Mechanical milling of metallic powders and producing nanosized giving ultimate severe deformation to the metal milled metallic grains within the powder particles. If the mechanically powders were successfully consolidated to bulk without loosing the fine grained microstructure, we ought to be able to obtain ultra fine grained bulk materials. In this paper, the MMC process (Mechanical Milling & Consolidation process) will be introduced for iron as a technique to fabricate ultra fine grained bulk materials and be discussed on the Hall- Petch relationship of iron materials in the ultra fine grained region. 3:30 PM Grain-Size Evolution in Nanocrystalline Fe during Mechani- cal Arttrition Michigan, Dept. of Nucl. Eng. & Rad. Sci. and Matls. Sci. & Eng., Cooley Bldg./North Campus, Ann Arbor, MI 48109-2104 USA; 35 West, Idaho Falls, ID 83402 USA Falls, ID 83402 Idaho 35 West, with by processing alloys in several were obtained grains Ultrafine Copper (OFHC), Alloy 101 were Copper processed Materials ECAE. high purity 270 (99.97% pure), brass), Nickel Alloy Alloy 260 (70/30 ultrafine Alloy 1100. In all cases, and Aluminum aluminum (99.999%), the ECAE multiple passes through were produced with grains (<1um) as-processed analysis of property and microstructural die. Mechanical less in the grain stability to be much material showed the and annealed alloys. in the more “dirty” materials than was observed high purity the a very high level of stored energy in ECAE processing produces a strong driving force for grain growth microstructure which provides temperatures if grain boundaries are rela- at relatively low annealing or impurities tend to pin the grain bound- tively clean. Any dispersions ultrafine grains. aries and stabilize the 2:50 PM Methods to Achieve Extremely Large Multiaxis Deformation Grain Steels Strains and Ultrafine Ferguson Poestenkill, NY 12140 USA Box 1234, P.O. is often achieved by severe plastic deformation. Ultrafine grain size been developed to achieve severe plastic defor- A few techniques have pressing/extrusion, tor- mation, such as equal channel angular (ECA) (ARB) techniques. This sion straining, and accumulative roll bonding which can achieve paper will introduce multiaxis deformation techniques dif- Two strains with constant deformation volume. extremely large with a different num- ferent types of hot deformation methods, each two-axis deformation ber of deformation axis, are studied. They are can be fully and three-axis deformation. The two-axis deformation deformation has restrained or unrestrained lengthwise. The three-axis restraint compression no restraint. The bulk volume of multiaxis full test samples for specimens can be easily machined into mechanical studies. A plain carbon mechanical property measurements and other Restraint Compres- steel (AISI 1018) was studied using the Multi-Axis Inc.. One micron grain sion system developed at Dynamic Systems The ultimate tensile size was achieved with the plain carbon steel. that of the convention- strength measured doubled, when compared to ally hot rolled material. 3:10 PM Iron through Mechani- Fabrication of Ultra Fine Grained Bulk cal Milling of Iron Powder Dr., Idaho Falls, ID 83415-1225 USA; 83415-1225 Falls, ID Idaho Dr., ; ; 2 2 Naval Air 2 ; Jenya Macheret 1 ; Rabindranath Mahapatra 1 ; Thomas M. Lillo 1 Rajiv S. Mishra, University of Rajiv S. Mishra, University Room: Polk A/B Location: Opryland Convention Center Shankar M.L. Sastry : Washington University, Mech. Eng. Dept., Campus Mech. University, Washington Gary E. Korth Materials Processing and Manufacturing Materials Processing S. Lee Semiatin, Air Force Research 1 Idaho National Engineering and Environmental Labo- 1 : ; 3 ; 3 U.S. Department of Energy, Idaho Operat. Off., 850 Energy Idaho Operat. Off., U.S. Department of Energy, U.S. Naval Academy, Mech. Eng., 590 Holloway Rd., Annapo- Mech. Eng., 590 Holloway U.S. Naval Academy, 2 3 ratory, Met. and Cer., P.O. Box 1625, Idaho Falls, ID 83415-2218 P.O. Met. and Cer., ratory, USA; Warfare Center, Aircraft, Matls. Lab., Patuxent River, MD 20670 Aircraft, Matls. Lab., Patuxent River, Center, Warfare USA; John E. Flinn Box 1185, One Brookings Dr., St. Louis, MO 63130 USA; One Brookings Dr., Box 1185, lis, MD USA With the objectives of producing sub micron grains and determining the beneficial effects of such sub micron grained microstructures on mechanical properties, several gamma+alpha2 based Ti-Al-X (X= Nb, Cr, Mn,Mo) alloys were processed by equal channel angular extrusion (ECAE) at 1200-1500K. 6-12 mm diameter cylindrical specimens were produced by multiples passes at different temperatures and were annealed at 1300-1600K. Microstructures of as processed and annealed specimens were determined by transmission and scanning elec- Hardnesses, bend strengths, and bend ductilities were tron microscopy. evaluated as functions of the temperature, deformation rate, and number of passes. Whereas in conventionally processed materials, the grain sizes were 10-50 micrometers, the grain sizes were < 2 micrometers in ECAE processed and annealed conditions. Furthermore there was ample evidence for the break up and conversion of gamma|alpha2 lamellar morphology to equaixed gamma and alpha2 grains. The effects of microstructural modifications on mechanical properties were determined. 2:25 PM Invited Ultrafine Grained Materials by Equal Channel Angular Pro- cessing (ECAE) 2:00 PM Invited by Equal Channel Grain Refinement of Titanium Aliminides Angular Extrusion Dennis Hasson Sponsored by: Tuesday PM Ultrafine Grained Materials: Severe Ultrafine Grained Processing: II Plastic Deformation Committee, Shaping and Division, Powder Metallurgy Forming Committee Program Organizers: Engineering, Rolla, MO 65409-0340 Missouri, Metallurgical Director- Materials Laboratory, USA; S. L. Semiatin, Wright Colorado ate, Dayton, OH 45440 USA; C. Suryanarayana, and Materials School of Mines, Department of Metal Thadhani, Engineering, Golden, CO 80401 USA; Naresh School of Materials Institute of Technology, Georgia USA Science and Engineering, Atlanta, GA 30332-0245 March 14, 2000 Session Chair: Air Force Base, OH 45433- Wright-Patterson Laboratory, 7817 USA homogeneous capillary, a stripwise binary capillary with or without with or capillary stripwise binary a capillary, homogeneous pores shrinking capillary with and a homogenous effects, gravitational Si of by molten the penetration for calculations reaction. Model due to that time-depen- binary) show phase or (single Si3N4 capillaries C and a binary kinetics. With angles retard the penetration dent contact profiles that match yields stepped infiltration the analysis capillary, angles for both contact effective based upon Cassie’s the predictions out- situations. The computational and gravity-inclusive gravity-free shrinking pore and time-dependent combined effects of comes for the work in of recent experimental are assessed in light contact angles reactive systems.

TUESDAY PM 115 Angular Extrusion Severe PlasticDeformationofTi-6Al-4VviaEqualChannel 4:25 PMInvited of ultrafinegrainformationarediscussed. Effects ofinitialgrainsizeandsecondaryphasesonthemechanisms boundaries ofultrafinegrains.Itleadstodecreaseinternalstresses. into grainboundaries.Atthirdstagearecoveryprocessoccurs highly non-equilibriumduetohighdensityofextrinsicdislocations tive. Thismechanismisconsideredindetails.Formedstructure observed. Aspecificmechanismforultrafinegrainformationisopera- in finecrystallitesandastrongincreaseoflatticedislocationdensityis place. Atsecondstageofmicrostructuralevolutionasingleslipoccurs at moderatetemperaturesandrefinementofinitialstructuretakes tures resultsingrainseparation.Dynamicrecrystallizationmayoccur with highvaluesofSFEaformationlowenergydislocationsstruc- twinning providesthissubdivisionatambienttemperature.Inmaterial fragments occurs.InmaterialswithlowvaluesofSFEadeformation sists ofthreestages.Atfirststagethesubdivisionifinitialgrainsinto talline grainformation.Ingeneralthemicrostructuralevolutioncon- strongly influencemechanismofnanocrystallineandsubmicrocrys- tion. Itwasshownthatstackingfaultenergy(SFE)andtemperature performed torevealoperatingmechanismsofultrafinegrainforma- mechanical properties,X-rayexaminationandTEMobservationswere loys wereprocessedbyECAEatenhancedtemperatures.Evaluationof ambient temperaturebyusingofBridgemananvil.Fewaluminumal- 0.65%Zr, aluminumalloy2219and15Cr25Tisteelwerestrainedat were usedtodeformbulkmaterials.AmagnesiumalloyMg-5.8%Zn- structural evolutionduringsevereplasticdeformation.Two techniques Presentworkisanoverviewofexperimentaldatadealtwithmicro- ity ProblemsRAS,Khalturina39,Ufa450001Russia Rsch. Ctr., 1-1Minamiwatarida-cho,Kawasaki-ku, Kawasaki-shi210- Super MetalConsortium ofJapan,NKKCorp.Matls. &Processing Yokota on AusteniteGrainSizein 0.3%C-9%Ni Steel Effect ofLarge-StrainDeformation PriortoAustenitization 4:50 PM mation duringECAE,andtheresulting microstructuresaredescribed. material flowproperties,processing conditions,macroscopicdefor- various processingroutesarecompared.Therelationshipsbetween resulting fromECAEperformedatvarioustemperaturesandusing or anequiaxedalphapreformmicrostructure.Microstructuralfeatures effects ofECAEprocessingonTi-6Al-4Vbilletshavingeitheralamellar crystallographic orientations.Physicalmodelswereusedtostudy the throughout theworkpiecerefiningmicrostructureandaffecting Under idealconditions,thesimplesheardeformationoccursuniformly mation occursintheformofsimpleshearconfinedtoanarrowzone. changing theoveralldimensionsofworkpiece.Incrementaldefor- vere plasticdeformationthroughoutabulksectionofmaterialwithout Theequalchannelangularextrusionprocess(ECAE)imposes se- OH 45433-7817USA Manufact. Direct.,AFRL/MLLM,Wright-PattersonAirForceBase, Research Laboratory, Matls.Process.andSci., Hone Corporation,1IndustryBlvd.,Irwin,PA 15642USA; tic Deformation Mechanisms ofUltrafineGrainFormationduringSeverePlas- 4:00 PMInvited 3:50 PMBreak ball-milled supersaturatedsolidsolutionwillbepresented. application oftheresultstoobservednon-monotonicprecipitationin or pointdefectsisobservedtodecreasewiththemillingamplitude.An fraction oftheimpactenergywhichisconvertedintograinboundaries contribution tothegrain-growthtermisnoticeableabove473K.The with thedominanceofnonequilibriumdefects.Athermallyactivated coefficient forgraingrowthisnegligiblebelow473K,inagreement assumptions made.Inparticular,theactivationenergyforkinetic a functionoftemperatureandmillingintensityisconsistentwiththe curves forallconditions,andthebehavioroffittingparametersas tion-enhanced diffusion.Themodelexpressionfitswellthetemporal formation wasincorporated,usingconceptsdevelopedtomodelradia- bution tograingrowthbynonequilibriumvacanciesgeneratedde- 1 ; Tetsuo Shiraga : R. Kaibyshev : David P. DeLo 1 ; MasakazuNiikura 1 ; 1 Institute forMetalsSuperplastic- 1 ; S.LeeSemiatin 1 ; KaoruSato : 2 2 ; ; 2 Tomoyuki Air Force 1 1 Extrude Ferrous Iron withOxideParticles Thermal StabilityofUltrafineGrainedFerriticStructure 5:10 PM discussed. metallurgical conditionforthespontaneoustransformationwillbe taneous transformation.Transformationmechanismandrequired heating duetodeformationwassuggestedcontributesuchaspon- cron, anditshowedhardnessoffullyquenchedmartensite.Adiabatic size ofthespecimenwasremarkablyrefineddowntoaround0.5mi- reheating. ItwasrevealedbyTEMobservationthataustenitegrain induced bysuchalargestraindeformationevenwithoutsubsequent for thereductionabove70%.Spontaneousreversetransformationwas heating. Drasticchangeinreversetransformationbehaviorwasfound reheating toaustenitizationtemperature(700 ously refinedaustenitegrainsizedownto2micronaftersubsequent deformation simulator. Increaseinreductionratioupto50%continu- single passbycompressionofcylindricalspecimensusinglaboratory with extremelyhighhardness.Deformationupto70%wasdoneina once reversetransformationoccurs,austenitetransformsmartensite ied using0.3%C-9%Nisteel.Becausethissteelhashighhardenability, tion temperatureonaustenitegrainsizeafteraustenitizationwasstud- strain deformationatatemperaturerangejustbelowAc1transforma- effect onaustenitegrainsize,andinthispaper,theoflarge- deformation priortoaustenitizationisknownhaveabeneficial factors formicrostructuralcontrolinheattreatment.Coldorwarm austenite grainsizerefinement,whichisoneofthemostimportant Development Organization).Oneeffortwithinthisnationalprojectis project supportedbyNEDO(NewEnergy andIndustrialTechnology 1micron insteeliscurrentlyunderwayas“FerrousSuperMetal” Fundamentalresearchprojecttopursueultrafinegrainsizebelow Kawasaki-shi 210-0855Japan App. Tech. Rsch.Ctr., 1-1Minamiwatarida-cho,Kawasaki-ku, 0855 Japan; and theZenerpinningeffectofoxideparticles. structures weretheninvestigatedinrelationtothestructuralchange dated tobulkmaterials.Thethermalstabilityofultrafineferritegrain powders withoxideparticlesweremechanicallymilledandconsoli- and thenre-precipitatedveryfinelyonannealing.Inthispaper,iron persed butalsodecomposedduringultragrainrefiningofthematrix particles, whicharethermodynamicallysostable,werenotonlydis- firmed inferriticstainlesssteelpowdersthatalargeamountofoxide nm orless(chargedtruestrainismorethan10).Moreover,wecon- mate work-hardeningbasedontheultragrainrefiningtoaboutfewten kneading reaction.Sufficientmillingtreatmentfinallycausesanulti- metals, becauseendlesscyclicdeformationcanbeperformedthrough Mechanicalmillingisveryeffectiveforchargingalargestraininto 812-8581 Japan Eng., Grad.Schoolof6-10-1Hakozaki,Higashi-ku,Fukuoka Tsukuba, Ibaraki305-0047Japan; Institute forMetals,FrontierRsch.Ctr. forStruct.Matls.,1-2-1Sengen, Hideyuki Hidaka 2 Ferrous SuperMetalConsortiumofJapan,NKKCorp. 2 ; HidetoGoto : 2 ; SetsuoTakaki Yuuji Kimura 2 Kyushu University, Matls.Sci.and ° C) byinductionrapid 1 2 ; SatoruNakamyo ; 1 National Research 2 ;

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Opryland Convention Center Center Convention Opryland Daily Personal Schedule - Wednesday - March 15 March - Wednesday - Schedule Personal Daily

WEDNESDAY AM 117 reactive materials withoutcontaminationformcrucible walls.One environment forstudying materialsintheundercooled stateandhighly ten materials.Inparticular,containerless processingoffersandideal the nucleation,solidification,and thermophysicalpropertiesofmol- Acontainerlessenvironmentoffers severaladvantagesforstudying Huntsville, AL35812USA W. Hyers tem attheMarshallSpaceFlight Center Solidification Studiesfromthe ElectrostaticLevitationSys- 8:50 AM the variationininterfacialenergyofsystem. the breakupandreunificationofDLMwillalsobediscussedwith will bediscussed.Theeffectoftheapplicationultrasonicwave on mental factorstoaffectthestabilityandtransformationofDLM transformation processoftheDLMwascarefullyobserved.Funda- water wassuccessfullyproducedinaplateautankfacilityand the cesses undermicrogravity. TheDLMconsistingofsiliconeoiland two liquidphases.Thiscanbewellappliedinthecontainer-freepro- dures, wherethereactionoccursatalloverinterfacebetween the may beoneofthepromisingmaterialrefiningandprocessingproce- spherical liquidmassiscoveredwiththesecondlayerorshell, undertaken inTokai University, Japan.TheDLM,inwhichthefirst ThestudyofDouble-layeredLiquidMassundermicrogravityis 1292 Japan 1 Takahashi Double-Layered LiquidMassUnderMicrogravity 8:30 AM Canada Dept. ofMatls.andMetallu.Eng.,KingstonK7L3N6 Session Chair: March 15,2000 Wednesday AM gna, DepartimentodiFisica,BolognaI-40126Italy Barton, VT05822USA;CarloPatuelli,UniversitadiBolo- Program Organizers: Committee Phases Committee,Thermodynamics&PhaseEquilibria Materials Division,StructuralAlloy Critical Technology Sector, Electronic,Magnetic&Photonic Sponsored by: Materials Science:Session3 Experimental MethodsforMicrogravity 12th InternationalSymposiumon Tokai University, Dept.ofMetallu.Eng.,Hiratsuka,Kanagawa259- "Some GeneralitiesintheAnalysesofEquilibriaIonicSolutions" Convention Center,PresidentialBallroom-JeffersonA Institute ofMetalsLecture&RobertF. MehlMedalist Convention Center, Tennessee Ballroom-Nashville "The AluminumIndustryoftheFuturePartnership" 1 1 ; MichaelB.Robinson ; Takamitsu Kurokawa ASM International:MaterialsScience Reginald W. Smith,Queen’s University, Location: OprylandConventionCenter Room: MemphisA Robert Schiffman,R.S.ResearchInc., LMD Luncheon Denise Swink Robert Rapp 12:00noon 12:00noon ✦✦✦ 1 ; KazuyukiShimamura 1 ; 1 NASA/MSFC, MailCodeSD47, : Jan R.Rogers WEDNESDAY AM 1 ; ItaruJimbo : 1 ; Robert Masato 1 ; LMS Mission The Source ofVoids inAl-InSamplesProcessed duringthe 9:10 AM alloys, solidificationvelocity, anddiscussesrelatedmicrostructures. perature, transformation(TTT)diagramsformetallicglass-forming Facility isdiscussedalongwithrecentmeasurementsfortime,tem- an electrostaticlevitator(ESL).ThecurrentstatusoftheMSFCESL relatively newtechnologyforcontainerlessprocessingofmaterialsis mine theEffect of ConvectiveFlowonInterface Stability The Directional SolidificationofHypermonotectics toDeter- 10:30 AM Research. ton, DCundergrantN00014-94-1-GO16 fromtheOfficeofNaval GM51018 andinpartbytheNaval ResearchLaboratoryinWashing- Sciences oftheNationalInstitutes ofHealththroughgrant1R15 This researchwassponsoredbythe NationalInstituteofGeneralMedical modify standardnucleationtheorytotaketheseeffectsintoaccount. species, whichservestoacceleratetheirrateofagglomeration. We solved saltproduceDebye-Huckelplasmascreeningofthesecharged of H charge, weproposeanucleationmechanismwhichincludesdonation prevent thedimeranditssuccessornucleifrombuildinganexcessive nism istheformationofadimerfromtwothesemacro-ions. To highly chargedmacro-ions.Thefirststepinthenucleationmecha- strong electrolytes.Inaqueoussolution,proteinmoleculesexist as ProteincrystalsnucleatefrompHbufferedaqueoussolutions of Huntsville, AL35899USA cooled Semiconductors Growth Velocity-Interface FigurationRelationshipsinUnder- 9:30 AM way tohelpcontrolthisdifficultyinthefuture. attempt toidentifythesourceofthesevoidsandmodificationsunder- The presentationwilladdresstheresultsoftestscarriedoutinan fication shrinkage,and4)loadingsealingtheampouleundervacuum. spring arrangementtocompensateforthermalcontractionandsolidi- of allportionstheampouleassembly, 3)theuseofapistonand included: 1)vacuuminductionmeltingthealloys,2)bake-out likelihood ofvoid/gasbubbleformationinthesesamples.Stepstaken the solidificationprocess.Greatpainshadbeentakentominimize small voidsinsomeareasthatweresufficientsizetolocallyperturb flight analysisrevealedthattwoofthethreesamplescontained aspects ofsolidificationprocessesinimmisciblealloysystems.Post- Growth inHypermonotecticsthatisdesignedtostudyfundamental These sampleswerepartofanongoingexperimententitledCoupled fied duringtheSTS-78LifeandMicrogravitySpacelabshuttlemission. Three aluminum-indiumimmisciblealloysweredirectionallysolidi- Birmingham, AL35294USA Alabama, Dept.ofMatls.Mech.Eng.,1150 10thAve. S.,BEC254, Crystals Effect ofBufferandSaltontheRateNucleationProtein 10:10 AM 9:50 AMBreak change ofthesolid-liquidinterfacefiguration. The transitionofthedendritegrowthbehaviorwasobservedfrom cooling bymeansoftwophotodiodesandahigh-speedvideocamera. The crystalgrowthvelocitiesweremeasuredasafunctionofunder- an electromagneticlevitatorcombinedwithalaserheatingfacility. present experiment,pureSi,Geandtheiralloyswereundercooledby with respectstothecriticalundercoolingfortransition.In alloys. However,therearemanydiscrepancybetweentheirresults tinuous growthinsolidificationofundercooledpureGeandGe-based Several investigatorshavereportedthetransitionfromlateraltocon- undercooled meltisexpectedtobedifferentfromthatofametal. Acrystalgrowthbehaviorofasemiconductingmaterialfromdeeply Kanagawa 229-8510Japan tute ofSpaceandAstronauticalScience,3-1-1Yoshinodai, Sagamihara, + tothebuffer. We suggestthattheionscontributedbydis- : James K.Baird : J. B.Andrews : 1 ; T. Aoyama 1 1 ; L.J.Hayes University ofAlabama,Dept.Chem., 1 ; K.Kuribayashi 1 ; D.Downs 1 ; 1 ; 1 University of 1 The Insti- : J. D.

WEDNESDAY AM 118 ; ; 1 1 FFE Min- 1 ; 3 Suresh K. Bhargava Benny Erik Raahauge : : ; Martín Gayol 3 Alcoa Europe, Apartado de 3 C) to produce smelting grade ° ; José Pulpeiro 2 Vito Cedro, Alcoa World Alumina, World Cedro, Alcoa Vito Room: Jefferson B Convention Center Location: Opryland Ashwadama Pasupulatey, Alcoa World Ashwadama Pasupulatey, Light Metals Division, Aluminum Committee Division, Aluminum Light Metals ; Hélène Boily 1 Alcan International Limited, Banbury Lab., Southam Rd., 2 RMIT University, Dept. of Appl. Chem., GPO Box 2476V, Melbourne, of Appl. Chem., GPO Box 2476V, Dept. RMIT University, Jens Fenger Allé, Copenhagen DK 2500 Den- erals DK A/S, MIA, 77 Vigerslev mark; Oxfordshire OX16 7SP UK; Banbury, Correos 71, San Ciprián (Lugo) ES 27890 The first Solid-Liquid Calcination plant for destruction of organics San in Bayer plant liquor was commissioned in 1999 at Alcoa Europe’s Ciprián plant in Spain. The paper compares the first year of operational experience with the design criteria and reports on the testing of alumina dust from a calciner as a feed component. Alumina and Bauxite: Bayer Process Bayer Bauxite: and Alumina Development by: Sponsored Organizers: Program Alumina Queensland USA; Joe Anjier, 15219 PA Pittsburgh, 4680 Australia Queensland Limited, Gladstone, AM Wednesday March 15, 2000 Session Chair: TX 77971 USA Alumina, Point Comfort, 8:30 AM Invited Bayer Liquor Organics Removal from 1 3001 Australia Victoria alumina from bauxite is The Bayer process for the production of smelting grade alumina. The used to produce ~95% of the world’s of aluminum hydrox- initial reaction in this process is the dissolution to produce sodium ide Al(OH)3 and AlO(OH) in hot sodium hydroxide impurities (mostly aluminate Na+Al(OH)-4. After removal of insoluble {gibbsite-Al(OH)3}. quartz and fine iron oxides) the aluminum hydroxide This is subsequently calcined (10000 and has only a very small alumina Al2O3). The Bayer process is cyclic any organic Consequently, bleed of solution with the insoluble residues. accumulate in the Bayer substance, which is soluble in hot alkali, will concentration. For process liquor to reach a very high steady-state hydroxide/alumi- example, starting with a pure Bayer liquor (sodium step will result in nate), each passage through the bauxite digestion carbon (TOC). How- solution containing ~0.4g/L of the total organic ~30g/L. This especially ever, the steady-state TOC concentration is Australian alumina refineries, which process very trues for Western and fulvic acids and low-grade bauxite. Such impurities may be humic rank coal precursors, salts, tannins and other polyphenolic salts, low been classified according and their degradation products. These have of these dissolved to their molecular weight distribution. The presence processing problems and organics pollutants (or TOC) causes major hydroxide yield, production inefficiencies including: Reduced aluminum hydrate, interference impure aluminum hydroxide, colored aluminum of process liquor and with flocculation of iron oxide residues, foaming devised to reduce Many processes have been increased liquor viscosity. very However, liquor. from the Bayer the concentration of organics few of these suggested processes have been put into commercial use One successful since they are generally capital expansive and risky. process that is in use at certain alumina refineries is “liquor burning”. This is based upon technology licensed from a Japanese company- Showa. However, this is also capital intensive, expansive and associated with other air pollution problems. This lecture will discuss various issues related to limitation caused by organics on the Bayer process production and probable solutions to reduce or remove these organic pollutants from the aluminate liquor of Bayer process. 9:15 AM of Operation of the SLC Process A Year DEM/ 1 ; Vanderbilt 1 1 ; 2 ; D. Camel 1 ; R. N. Grugel 1 M. D. Dupouy : ; A. Anilkumar 1 University of Alabama, Dept. of Matls. and of Matls. Dept. of Alabama, University 1 ; 1 ; Q. Kou 1 University Space Research Association, Huntsville, AL University Space Research 2 ; J. B. Andrews ; J. B. J. Bhowmick 1 : SPCM, CEA-Grenoble, 17 Rue Des Martyrs, Grenoble, Cedex 38054 SPCM, CEA-Grenoble, 17 Rue Des Martyrs, France in castings is well known The formation of equiaxed microstructures sedimentation. Following to be strongly influenced by convection and and LMS96 our previous experiments performed during EUROMIR95 in refined Al-4wt%Cu missions on the Columnar to Equiaxed Transition and space experi- alloys [1-3], a new series of comparative ground multigrain equiaxed ments has been performed in order to analyse with a smalll solidifica- solidification. A refined Al-3.5wt%Ni alloy, been chosen in order to tion interval and a high eutectic fraction, has directly reveal the morphology of the growing solid frozen at an early stage by the eutectic transformation of the remaining liquid. Samples of this alloy were directionally solidified with several velocity steps, 98, respectively in the AGHF furnace during STS-95 mission (Nov. AGHF6 experiment), and in TITUS during MIR-PERSEUS (May-June 99, collaboration with ACCESS). Comparative ground experiments present here the preliminary were performed vertically upwards. We results of the experiment AGHF6: Space samples show a homogeneous dendritic equiaxed structure with increasing grain sizes for decreasing solidification rates. By contrast, a transition to mixed columnar- equiaxed and then purely columnar structures is observed in ground samples. Morphological parameters of the microstructures are determined by Image Analysis, and the influence of gravity driven convection on these morphologies is discussed in relation with the radial D. Camel, macrosegregation observed on the ground. [1] M.D. Dupouy, Proc. 8th Int. Conf. on Modeling Botalla, J. Abadie and J.J. Favier, F. and Advanced Solidification Processes, San Diego of Casting, Welding Botalla, J. Abadie, J.J. D. Camel, F. 1998, p.415. [2] M.D. Dupouy, D. XI/1 (1998), p.1. [3] M.D. Dupouy, Techn. Sci. Microgr. Favier, Camel, J.E. Mazille and I. Hugon, Proc. 3rd Int. Conf. Solidification April 26-29, 1999. Miskolc, Hungary, And Gravity, University, Ctr. for Microgravity Rsch. and Appls., Nashville, TN for Microgravity Ctr. University, 37235 USA; 35812 USA experiments with NaNO3 revealed that steady Our previous flat zone by the con- thermocapillary flow (TC flow) can be balanced/offset by end-wall vibra- trolled surface streaming flow (CSS flow), induced the effects of tion. In the current experiments, we are examining oscillatory thermocap- surface streaming flow on steadying/stabilizing this effect, we have set up a controlled NaNO3 half- To illary flow. like zone dimen- zone experiment, where the processing parameters varied to achieve oscilla- sions and temperature gradients can be easily of we discuss the thermal signature In the present paper, tory TC flow. The of CSS flow. by imposition and how it is affected the TC flow, of a NaNO3- results will also include a comparison of the microstructure TC conditions, with Ba(NO3)2 eutectic, processed under oscillatory and without imposed CSS flow. AM 11:10 Solidification of a Effect of Gravity on Directional Equiaxed Refined AL-3.5WT%NI Alloy Mech. Eng., 1150 10th Ave., SBEC 254, Birmingham, AL 35294 USA AL 254, Birmingham, SBEC Ave., 10th Eng., 1150 Mech. was succinonitrile-glycerol system transparent-metal-analog The flow of convective the effect determine observe and directly used to directionally so- alloys were Hypermonotectic stability. on interface Samples were microscope. a temperature-gradient-stage lidified using No flow stabil- to minimize flow. horizontally in order first processed the growth increasing determined by systematically ity limits were then orientations were processing Vertical instability. rates to promote limits. The stability to determine the flow-modified used in order the increased in order to decrease sample thickness was systematically Different hypermonotectic com- the fluid flow. amount of damping on the so that a comparison could be made on positions were studied and convective flow on interface sta- influence of both composition bility. 10:50 AM Thermocapillary on Oscillatory Vibration Effects of End-Wall Flow Barnes

WEDNESDAY AM 119 Strength Conditions of Gibbsite(aBayerProcessSolid)underHighIonic,pH The AdsorptionofSodiumOxalateStabilizerstotheSurface 10:25 AM 10:05 AMBreak regeneration andrepeatedapplicationarepursuedfurther. cess” thelossesofaluminaareminimum.Somefeasiblevariations putting sorbenthavegreatimpactonthesorption,andat“LGIPro- losses ofaluminawerestudied.Itwasestablishedthatamounts sium compoundsonresultsofthesorptionorganicsubstancesand ture, durationofthetreatment,concentrationputtingmagne- process evaporatedliquorswasconsidered.Theinfluenceoftempera- number reasonablemagnesiumcompoundsforpurificationofBayer of organicsubstancesandre-usable.Thepossibilityapplication was determined.Analkalineearthcompoundsareattractiveassorbent organic substancesinevaporatedspentliquorbygravimetricmethod liquor averagesbetween1.5kgand2kg.Thefractiondistributionof The extractionfromonetonofbauxiteorganicsubstancesatgreen of organicsubstancesistheDarlingRangebauxitedistinctivefeature. initial bauxiteorganicinchemicalconstitution.Theelevatedcontent great transformations.Theformedneworganicsubstancesdifferfrom quence ofrepeatedcirculationtheorganicsubstancesaresubjectedto Bayer processduringlongtimeisstockpiledinspentliquor. Inconse- interacted withalkalineliquors,andstilltheyrepeatedcirculatingin Bayer processsubstantially. Itarrivingattheprocessfrombauxitesis Theorganicsubstanceshaveanimpactondifferentoperationsin Aluminum Corporation, Shangjie,Zhenzhou,Henan 450041China China Tube Digestion Technology forTreating Diaspore Bauxite in 11:15 AM raise thetarget oftechnologyandeconomy. crease theoutputofballmill,decrease theenergyconsumptionand from othergrindingflowsheets in applicationatpresent.Itcanin- classifier, canpreparequalifiedslurry. Thisnewtechnologyisdifferent new technology, withahydrauliccycloneinsteadofthepreviousspiral meet thedemandsofparticlesizecompositionintubedigestion. A circuit grindingwithaballmillandspiralclassifier,cannoteasily SlurryinBayerProcess,preparedbythetraditionalonestageclosed- of Metallu.,Changsha,Hunan410083China Shanxi 043300China; Guihua Zhang Chengzhong A NewTechnology ofSlurry Preparation forBayerProcess 10:50 AM liquors (highionicstrength,extremelyalkalinemedia). gibbsite (andotherBayerprocesssolids)insyntheticand gibbsite, whilstalsoleadingtotheinsituinvestigationofsurface sition of“doseresponse”curvesfortheaforementionedQAson C16

WEDNESDAY AM 120 ; 2 Alcoa 1 ; 1 ; Tseng T. Tseng ; 2 Pier Enterprises 3 ; John T. Pisano ; John T. ; E. Dolin 1 1 ; Chris Cleary 1 Unisearch Associates Inc., 2 Comalco Aluminium Limited, 2 ; V. Bakshi ; V. 1 ; Andre Abbe 1 Boyne Smelters Ltd, Reduction Lines Boyne Smelters Ltd, 3 ; R. Roberts 1 Elaine Yee-Leng Sum Elaine Yee-Leng Rudolf Heger : Hamburger Aluminuim-Werk GmbH, Dradenauer Aluminuim-Werk Hamburger 1 : ; 3 Jerry Marks : Comalco Research & Technical Support, 15 Edgars Rd., Support, Technical Comalco Research & 1 ; 3 Matthias Franz Hauptdeich 15, Hamburg 21129 Germany; Concord, Onatrio L4K1K8 Canada; 96 Bradwick Dr., 7, Hattersheim 65795 Germany GmbH & Co. KG, Voltastrasse to stricter legislation forcing smelters outside these areas to install areas to outside these smelters forcing legislation to stricter 80% approximately represents The electrolysis systems. SO2 control 95% for and approximately smelters for prebake released SO2 of the legis- SO2 removal current is addressing The paper smelters. Söderberg the Alu- technologies applied within as current removal lation as well cost per ton and operational with focus on investment minum industry SO2 removed. Break 10:15 AM 10:25 AM HF Fugitive Emissions through Understanding and Controlling Characterisation and Air Velocity Continuous HF Monitoring in Reduction Lines Khoo 3074 Australia; Thomastown, Victoria Boyne Island, Line 3, Handley Dr., Boyne Smelters Reduction Queensland 4680 Australia; Island, Queensland 4680 Australia 1&2, Handley Drive, Boyne were studied at Boyne Smelters Ltd., an alu- HF fugative emissions with two different technologies. Fugative minium smelter operating cells, anode butts, bath sows, Pacman skips emissions from reduction were characterised by an open path FITR and open metal crucibles draught and cell design The effects of bath chemistry, spectrometer. Real time monitoring by on fugative cell emissions were investigated. tool for improving a continuous HF gas analyser provided a useful The air velocity pro- work practises and reducing fugative emissions. using an array of vane file in the reduction line roof was characterised air velocity underlined anemometers. The diurnal variation in the roof if intermittent moni- the importance of a proper sampling proceedure, optical air velocity toring is employed. A continuous, open path, new approach using an monitoring system was successfully trailed. A for monitoring roof ultrasonic anemometer was found to be suitable air velocity continuously. 10:50 AM Primary Aluminum Perfluorocarbon (PFC) Generation during Production Technical Center, 100 Tech. Dr., Alcoa Center, PA 15069-0001 USA 15069-0001 PA Alcoa Center, Dr., 100 Tech. Center, Technical working to improve The primary aluminum industry is continually performance. As production efficiency and enhance environmental Pro- Aluminum Industrial Partnership (VAIP) Voluntary part of EPA’s on reducing the gram, eleven U.S. primary producers are focusing which reduce aluminum duration and frequency of anode effects (AEs), (PFCs), CF4 and current efficiency and generate two perfluorocarbons contributing to C2F6. PFCs effectively trap heat in the atmosphere, and key better understand PFC emissions To the greenhouse effect. sponsored a second, data- factors influencing their generation, VAIP smelters (the results intensive measurement program at six aluminum at the 1998 TMS of the first round of measurements were reported meeting in San Antonio and appeared in Light Metals 1998—277- 285). At each smelter, PFCs were measured from the potroom exhaust emis- Fugitive ducts using a continuous real-time mass spectrometer. sions were sampled from roof exhausts and measured by FTIR spec- Emissions were related to facility operational parameters trometry. The real- AE duration, and AE over-voltage. such as AE frequency, time measurement capability provides the ability to generate highly time resolved emissions profiles of individual anode effects. This information gives new insights into the factors influencing emissions in addition to estimating overall smelter emissions. Several smelters provided data on the voltage profile of individual anode effects, which has shown correlation to emissions in both bench-scale laboratory studies at MIT and other measurements. The paper reviews the data, provides recommendations for improving PFC emissions predictability and suggests possible means for reducing these emissions. AM 11:15 for the Mea- Separate Technologies of Three Intercomparison Primary Alu- HAW the from of HF Stack Emissions surement minium Smelter ; 2 Hydro 2 Univer- 2 ; Morten Nancy C. 1 Svein Ole : : ; Margaret M. Hyland ; T. Foosnaes ; T. 1 1 Hydro Aluminium Metal 1 ; 1 ABB Environmental Norway, 1 ; 1 University of Auckland, Dept. Of 3 ; H. Kvande 1 ; G. Wedde 1 ; Kirsten L. Bolstad 2 Alistair Ross Gillespie Comalco Research and Technical Support, Alu- Support, Comalco Research and Technical 1 : ; 3 ; E. Bjornstad 1 ; Victoria Kielland ; Victoria 1 ; Marit S. Aalbu 1 Emission Control in the Aluminum Industry 2 Strømmen Flakt Div. for the Aluminium Industry, Postboks 6260 Etterstad, Oslo for the Aluminium Industry, Flakt Div. 0603 Norway SO2 emissions from the aluminum industry are modest on a worldwide and national scale. Large modern smelters using high-sulfur petroleum coke in anodes and smaller smelters with topographical unfa- This be significant sources locally. however, vorable conditions may, has lead environmental regulators to again review local legislation. Currently SO2 emission legislation is in force in Scandinavia and in some areas in the US. The ongoing review of SO2 emissions might lead Chem., Private Bag, Auckland 92019 New Zealand prevent discharge of Dry scrubbers at modern aluminium smelters by returning virtu- particulate material and gaseous hydrogen fluoride cell. As such, they ally all of the collected material to the electrolytic materials balance. Return have an important impact on the smelter’s requirement to add of fluoride is beneficial as it reduces the smelter’s aluminium fluoride to maintain constant bath ratio. On the other or chemically HF, hand, return of hydrogen in the form of water, bound hydroxyl, is not beneficial as this may result in release or regen- Data presented here show fluoride in dry scrubbed alu- eration of HF. mina to be bound as a hydrated aluminium-hydroxy-fluoride phase of of hydration is relatively weakly bound Water variable stoichiometry. and could participate in hydrolysis reactions in the fume, during cell feeding. Hydroxyl ions are more strongly bound and may participate in hydrolysis reactions with the electrolyte, or in self-hydrolysis of the aluminium hydroxy-fluoride. 9:50 AM SO sity of Auckland, Dept. of Chem. and Matls. Eng., Private Bag, sity of Auckland, Dept. of Chem. and Matls. Auckland 92019 New Zealand; mina Tech., 15 Edgars Rd., Thomastown, Vic 3074 Australia; 15 Edgars Rd., Thomastown, Vic mina Tech., Aluminium, Ardal Smelter, Norway Aluminium, Ardal Smelter, potline usually has higher roof emissions A traditional Soderberg work has been made over the last two than a prebake line. Much reduction of roof emissions and improve- decades and considerable atmosphere have been obtained. During ments of the internal working in Årdal were converted to point feeder 1998 the Soderberg potlines and identify and a new study was initiated to analyze technology, of potential. This study consists factors with further improvement operating routines, analysis of HF and dust emissions data, potroom elements such as ventilation conditions, alumina quality and technical and changes of raw feeding. It is found that technological elements for periods of high roof materials are the more important reasons HF and dust emissions from the pots emissions of the potline. Average with the ones with side with point feeding are not higher compared of alumina silos on breakers. It is observed that filling and fluidizing of alumina charac- the pots may cause dusting, and that a combination be a source for seasonal teristics and certain climatic conditions can does not contribute variations in roof emissions. Potroom ventilation at the center of the to unusually high emissions, however, conditions resulted in suggestions potroom may not be optimal. CFD simulations for improved working atmosphere. 9:25 AM from the Dry The Surface Chemistry of Secondary Alumina Scrubbing Process James B. Metson Karlsen Norway; Centre Årdal, Øvre Årdal N-6882 Products, Tech. sulfur is released as COS, which is not entirely oxidised to SO2 before to SO2 entirely oxidised is not as COS, which is released sulfur in the atmospheric critical gas COS is a environment. to the its release The stratosphere. into the to its transportability cycle, owing sulfur the dry its fate in nor is well understood, gas is not of this generation released of the sulfur gases the complete oxidation Ensuring scrubber. emitted. The to ensure COS is not is one strategy from the anode in the in anode effect frequency seen a dramatic reduction industry has modern pause and examine whether but we need to last two decades reducing them further. can be applied towards knowledge 9:00 AM in a Soderberg Potline Environmental Improvements Holt

WEDNESDAY AM 121 values, aftercalcination. Pitchcokeislessvariable inmicrostructure amounts ofisotropic andanisotropicstructureswhich candifferinLc leum cokes,presentlyusedforindirect measurements,havevarying indirectly determiningthedegree ofbakinganodes.Greenpetro- (Lc), indicatethatcoaltarpitch canbeeffectiveasameansfor pitch cokewithcalcinationtemperature andgraphitecrystallinesize anode binderpitch.Thecorrelation ofthemaximumreflectance for theindirectdeterminationof thecalcinationlevelofcokefrom of maturitycoal.Theadaptationthesetechniquesisproposed tance techniqueshavebeenusedsuccessfullytocharacterizethedegree of coalinvariousmechanicalandthermalprocesses.Vitrinite reflec- Coalrank,ordegreeofmaturationcoal,influencesthebehavior Murrysville, PA 15668USA 26164 USA; num ofWV, PrimaryProductsDiv., P.O. Box98,Ravenswood,WV Coal Tar Pitch The RelationofReflectancetotheDegreeCalcination of 9:00 AM and routineoperations. various characteristicsvaluabletotheevaluationofprocesschanges minimal. Acursoryreviewofsmelterprocessmaterialswillalsoshow basic useofmicroscopictechniquesinmostsmelterlaboratoriesis advanced porestructure/volumemeasurementsofpetroleumcoke,the developments inrecentyearstheareasofmicroscopicimagingand to liquidpitchisalsopresented.Althoughtherehavebeensignificant green-anode pastecharacteristicsfromconversionofsolidpitchusage change, inacasestudyatCenturyAluminum’s Smelter. Theimpacton and howtheyprovedvaluableindefiningapetroleumcokequality sented. Includedisabriefreviewofthetechniquesusedinpetrography support ofaprocesscontrolsysteminanaluminumsmelterispre- Thevalueofroutineusecommonpetrographictechniquein 98, Ravenswood,WV26164USA thony Ross terial andProcessChangesinanAluminumSmelter The UseofPetrographic Techniques forEvaluationofRawMa- 8:30 AM Frankfurt/M D-65933Germany Session Chair: Room: March 15,2000 Knoxv Wednesday AM Aluminium Pechiney, StJeanDeMaurienne73303France Vaagsbygd, KristiansandN-4675Norway;ChristianDreyer, Program Organizers: Sponsored by: Properties andModeling Carbon Technology: Materials the 30tests. TDLAS instrumentationandthestandardmethodwasaround7%for measuring HFemissionsastheoverallaveragedeviationbetween vides aneffectivealternativetoothertechnologieswithrespect scrubber efficiencycontrol.TheTDLASinstrumentationused,pro- one second.Thisfastandaccurateresponsewouldlikelyenhance process duringtheevaluationperiodandhadresponsetimesasfast closely trackedthemanymanualmanipulationsdonetoscrubbing better agreementtothestandardmethod.TheTDLASresponsealso measurement methodsandinallbut5theTDLASinstrumentwas tation. Atotalnumberof30testswereconductedbetweenallthree Spectroscopy (TDLAS)withexistingpotentiometricbasedinstrumen- pounds (VDI-2286Part1)wasusedtocompareTunableDiodeLaser reference measurementprocedureforgaseousinorganicfluorinecom- technologies withrespecttoHFmeasurements.ThestandardVDI Tests wereconductedattheHAW smelterbetweenthreeseparate 1 ; 2 1 Coal PetrographicAssociatesInc.,3100BraunAve., Century Aluminum,PrimaryProductsDiv., P.O. Box : Light MetalsDivision,AluminumCommittee Frank Hiltmann,SGLCarbonGroup, J. AnthonyRoss Location: OprylandConventionCenter Morten Sorlie,ElkemASAResearch, 1 ; RayPatalsky ille A 2 ; 1 Century Alumi- : J. An- Application tostubholeandcollectorbarslotdesignisalsodiscussed. of predictingcontactresistancewithexistingtheoriesisdiscussed. ment withexperimentaldatawasfoundtobeexcellent.Thedifficulty tact pressureandtemperaturetoelectricalcontactresistance.Agree- to obtainasemi-empiricalconstitutiveequationrelatingnominalcon- [1] wasbuiltusingthecommercialcodeANSYS.Thismodelused mechanical finiteelementmodelofthe1992experimentM.Sørlie trical contactresistance.Here,anindirectlycoupledthermo-electro- did notprovideanypracticalmeansofpredictingtheinterfacialelec- made inthepastyears,bothsituandlaboratories.However,they anodic andcathodicassemblies.Numerousexperimentalstudieswere sis oftheelectricallossesatcastiron/carboninterfacesin amount ofelectricalpower. Energy savingstrategiesleadtotheanaly- TheHall-Héroultaluminumreductionprocessrequiresanenormous GOA1SO Canada 1000 evolution ofthesecharacteristicsbetweenroomtemperatureand resistivity, flexuralstrengthandfractureenergy measurements.The blocks hasbeenperformed,throughthermalconductivity, electrical also underelectrolysis.Characterizationofvariousgradesgraphite properties versustemperature,andconcerningelectricalresistivity been developedtocharacterizethermal,electricalandmechanical under conditionsasclosepossibletotherealconditions.Tests have electrolysis pots,measurementsoftheirpropertiesshouldbemade Inordertopredictthebehaviourofcathodicblocksinaluminium BP16, Venissieux 69631France 1 with Temperature Graphitised CathodeBlocksforAluminiumElectrolysisCells Evolution ofThermal,ElectricalandMechanicalProperties 9:25 AM reflectivity measurements. and presentsamorereliablemeansforthedeterminationofLc has beendeveloped, andisintheprocessofcommercialization for Anultrasonicsensorforcleanliness measurementinliquidmetals College St.,Toronto, OntarioM5S3E4Canada Sommerville for CleanlinessMeasurement inLiquidMetals Laboratory andIndustrialValidation ofanUltrasonicSensor 8:35 AM 8:30 AMIntroductoryRemarks OH 44202-8240USA Session Chair: March 15,2000 Wednesday AM 40202-2823 USA Corporation, DepartmentofEngineering,Louisville,KY USA; JamesN.O’Donnell,CommonwealthAluminum Corporation, GMPowertrainGroup,Pontiac,MI48340-2920 Program Organizers: Sponsored by: and Foundry Cast ShopTechnology: MeltQuality Canada; University, Chem.Eng./GIREF, PouliotBldg.,Ste-Foy, QuebecG1K7P4 Daniel Richard Steel andCarbonCylindersUsingtheFiniteElementMethod Thermo-Electro-Mechanical ModelingoftheContactbetween 9:50 AM 1000 Carbone Savoie,Lab.deRechercheetd’Essais,30,RueLouisJouvet, ° ° C canbeusedforpotmodelization. C isstudiedandcomparedtothecarbonblocksone.Values at 2 Alcoa-Lauralco, 1Boul.DesSources,Deschambault,Quebec 1 ; 1 ; M.Fafard 1 University ofToronto, Metallu. and Matls.Sci.,184 Light MetalsDivision,AluminumCommittee Elwin L.Rooy, Rooy&Associates,Aurora, : Bénédicte Allard Location: OprylandConventionCenter Room: Mississippi Paul Crepeau,GeneralMotors 1 ; R.Lacroix 1 ; J.M.Dreyfus 1 ; P. Clery 2 ; Y. Maltais 1 ; M.Lenclud : 2 Iain D. ; 1 Laval 1 : ;

WEDNESDAY AM 122 ; R. 2 Ravi : Ford Motor 1 ; E. Elder 1 ; 1 D. C. Chesonis : ; John E. Allison 1 Timminco S.A., 44 Chemin Petite- 1 Alcoa Inc., Ingot and Solidification, Alcoa Inc., Ingot and 1 ; 2 Shellcast Foundries Inc., Montreal North, 2 ; 1 ; S. Khan 1 ; Jacob W. Zindel ; Jacob W. 1 ; D. H. DeYoung 2 B. Closset : Alcoa Inc., Alcoa Mt. Holly, P.O. Box 1000, Goose Creek, SC 29445 Box 1000, P.O. Holly, Alcoa Inc., Alcoa Mt. Boissiere, Geneve CH-1208; Vijayaraghavan Ford Rsch. Labs., MD-2122 SRL, Dearborn, MI 48124- Company, 2053 USA The significant volumes of cast components required by the automotive industry provides an important opportunity for alloy refinement. One tool which is available for more efficient alloy design is computational thermodynamics. In this study we have used ThermoCalc, a software tool to calculate thermodynamic phase equilibria in complex multicomponent systems. The objective of this work is to study and demonstrate the potential of phase diagram calculation in refinement of cast aluminum alloys used in engine blocks and heads. Non-equilibrium solidification of a multicomponent 319 aluminum alloy was simulated under the Scheil condition using ThermoCalc. Results were quickly obtained, predicting evolution of fraction solid, of ThermoCalc predic- latent heat and phase formation. Validation Quebec H1G5L4 Canada amounts of stron- Several types of A357 alloy containing different bars were Test tium, berillyum, titanium and zinc were investigated. mechanical properties of cast in ceramic shell molds to measure the heat treatment the the different A357 alloys compositions. After were studied. The prop- microstructures and the mechanical properties cycles were compared to erties obtained after two new heat treatment the properties measured after a standard heat treatment cycle. It was shown that a small amount of berillyum (0.040%) added in combination to strontium modification increased significantly the mechanical properties (tensil strength, yield strength, elongation). The effect of the heat treatment on the Al-Si eutectic morphology has also been studied. AM 11:10 Alloy Refinement Using Computational Thermodynamics of the quality of final products from casting foundries and casthouses, foundries from casting final products quality of of the metal benchmark accurately operations world-class that it is important been widely has metal cleanliness today, and still For decades, quality. These samples. of solidified analysis metallographic using the monitored required tech- With filtering, the or may not be filtered. samples may results of — analysis consuming and resource-intensive niques are time delays. If no only after significant are obtained off-line grab samples and human from low sensitivity used, the results suffer filtering is of expressing proposes a new way The following paper interpretation. benchmark aluminum, and provides measurements of liquid cleanliness castings and wrought alloys. The paper also references for common conditions and the validity of these bench- provides the measurement of the instrument used to generate marks, and gives a description directly at-line. cleanliness measurements 10:15 AM Break 10:20 AM of Alcan Compact Degasser and Metal Quality Comparison Casthouse SNIF at Alcoa Mt. Holly O. Wood 15069 USA; PA Alcoa Center, Dr., 100 Technical Ctr., Alcoa Tech. 2 USA and hydrogen con- LiMCA and Alscan measurements of inclusion Casthouse to compare centrations were performed at the Mount Holly Degasser to that the metal quality obtained with an Alcan Compact The measurements were conducted at obtained with a SNIF degasser. the degassers. The in-line two casting pits that are identical except for SNIF degassing unit, metal treatment at one pit has a two stage, R-140 Identical Degasser. while the other pit uses a six rotor Alcan Compact the degassers. Data was ceramic foam filters are used downstream of a four day period. This obtained from 11 casts of 6xxx alloys over a statistical comparison paper will summarize the data and will provide concentrations en- between the two degassing units. LiMCA inclusion after the ceramic foam tering the degassers, inclusion concentrations the degassers, and the filters, hydrogen concentrations at the exit of hydrogen removal efficiencies will be compared. 10:45 AM of A357 Foundry and Heat Treatment Mechanical Properties Alloys : : ABB- 1 ; Jasmin ; 1 1 Jean-Claude ; VITO, Process VITO, 2 1 ; 3 Katholieke Hogeschool ; Paul Rochette 2 Alain A. Simard 1 ; J. Vits 2 : Péchiney Aluminium Engi- 3 ; Ronald Becher 2 VAW Highpural GmbH, P.O. Box Highpural GmbH, P.O. VAW 2 ; G. Mertens 1 ; François Dallaire 1 ; Werner Kapellner ; Werner 1 VAW Aluminium AG, R&D, Cast Shop Tech., P.O. Box P.O. Aluminium AG, R&D, Cast Shop Tech., VAW 1 ; F. De Schutter ; F. 1 ; ; Dany Veillette 3 1 Hayes Lemmerz Belgie BVBA, Lage Weg 392, Hoboken 2660 Bel- BVBA, Lage Weg Hayes Lemmerz Belgie D. Proulx Quebec G2E5S5 Bomem Inc., 450 St-Jean-Baptiste, Quebec City, Canada Quality Man- Total Benchmarking is an important aspect of today’s agement (TQM) and is a requirement for world-class corporations. Quality measurement is also required by standardization programs such as ISO9000 and QS9000. As liquid metal quality is an essential aspect R. Terrier 100664, Grevenbroich 41490 Germany; 24, Voreppe neering, Alpur and Casthouse Equip., Centr’Alp-B.P. 38341 France quality requirements Due to the steady increase of the customers’ ingots have to spend the producers of high purity aluminum rolling By optimization of the much effort on reducing the hydrogen content. highpural, a german producer of melting and casting process, VAW high purity aluminum, already achieved low hydrogen levels. In order to meet even higher requirements as for example for the production of high voltage capacitor foils a degassing system (ALPUR TS 35) was respect to possible melt contamination With installed additionally. with oxides, major selection criteria were a good sealing of the system against ambient air and an additional calming chamber within the box. For the evaluation of the system and the optimization of the degassing parameters, a systematic program of casting trials was carried out using AlSCAN and NOTORP measurements up- and downstream to whereas the capability of inclusion assess the degassing efficiency, measure- removal was evaluated by means of LiMCA and PoDFA ments. In general, a reduction of the hydrogen content from approx. 0.17 ml/100g Al (AlSCAN) to 0.10 ml/100g Al was achieved while the inclusion content in some cases slightly decreased. 9:50 AM Using the Prefil-Footprinter Instrument 2468, Bonn 53014 Germany; Leonhard Heusler Leonhard gium important gas in liquid aluminum and can have Hydrogen is the only In on the properties of the cast product. severe detrimental effect hydrogen content in liquid aluminum, several order to measure the and are used in tools for on-line measurements have been developed between these production facilities. However, a straight correlation guaranteed. Moreover, a measurements and the final product is not or shrinkage may distinction between pores originating from hydrogen In order to measure the be important to adjust the production process. methods such as hy- hydrogen concentration in solidified aluminum, This paper de- drogen extraction techniques have been developed. 2020) in order to scribes the use of such a system (Ströhlein H-MAT aluminum wheels. The evaluate the hydrogen concentration in cast calculated solidification obtained hydrogen data are compared with microscopic investiga- profiles and with test results of mechanical and the hydrogen concentrations. The results show a correlation between tion and the solidification profiles. 9:25 AM Purity Aluminum Achieving Low Hydrogen Content in High 3 Tech., Boeretang 200, Mol 2400 Belgium; Boeretang Tech., Kleinhoefstraat 4, Geel 2440 Belgium; Kempen, Campus HIKempen, aluminum melts. In this paper, attention is focussed on practical as- on practical is focussed attention In this paper, melts. aluminum location, width and of gate choice procedure, such as calibration pects and of the probes, movement and ease of handling the time setting, atten- Particular the casthouse. in ease of operation and the cheapness of the and the conversion paid to the signal processing tion has been format for trace to a user-friendly contained in the CRT information and attenu- roles of counting assimilation. The relative quick and easy of casting in the dynamic situation melt cleanliness ation in assessing in conduct sampling simultaneously and the ability to are explained, arrangements for various probe and the potential several locations, to other ancillary procedures which help are also discussed. Several are also described. validate the measurements 9:00 AM Hydrogen Concentration in Cast Alloys Measurements of the Jo Verwimp

WEDNESDAY AM 123 However, thereis asubstantialconservatismbuilt into theflawevalu- as thefailurecriterion forsafetyassessmentofnuclear powerplants. loading. Nowadays,theflawanalyses areperformedusing“limitload” nuclear reactorpressurevessels(RPV), whicharesubjectedtocyclic Surfaceandinternalcracksare theflawscommonlyobservedin TN 37996-2200USA; 2 Rd. ChiaanVillage, ChiaanVillage Lungtan,Taoyuan, Taiwan 325; Nuclear Energy Research,NuclearFuelsandMatls.Div., 1000Wenhua Roang ChingKuo ing Life Prediction ofReactorPressure Vessels underCyclicLoad- 8:30 AM Matls. Sci.&Eng.,Evanston,IL60208USA Johannes Weertman, NorthwesternUniversity, Dept.of Dept. ofMatls.Sci.&Min.Eng.,Berkeley, CA94720USA; Session Chairs: March 15,2000 Wednesday AM Engineering, Urbana,IL61801USA University ofIllinois,DepartmentMaterialsScienceand Engineering, Tempe, AZ85287-6106USA;J.K.Shang, University, Department ofMechanicalandAerospace Philadelphia, PA 19104USA;PedroD.Peralta,ArizonaState vania, DepartmentofMaterialsScienceandEngineering, Ontario Canada;CharlesMcMahon,UniversityofPennsyl- Department ofMetalsandMaterialsScience,Toronto, Program Organizers: Mechanical BehaviorofMaterials Critical Technology Sector, StructuralMaterialsDivision,Jt. Sponsored by: tiation, GrowthandFatigueLife(II) Professor CampbellLaird:CrackIni- Materials; ASymposiuminHonorof Cyclic DeformationandFatigueof soldering occurs. that promotesoldering,andthestrengthofbondformedwhen case ofpurealuminumand380alloycastinasteelmold,thefactors solidification. Thepaperdiscussesthemechanismofsolderingfor phase isliquidandjoinsthediewithcastingduringsubsequent surface ishigherthanthiscriticaltemperature,thealuminum-rich and solidintermetalliccompounds.Whenthetemperatureatdie begins toreactwithaluminumformanaluminum-richliquidphase vations. Asolderingcriticaltemperatureispostulatedatwhichiron ing. Asolderingmechanismispostulatedbasedonexperimentalobser- the morphologyandcompositionofphasesformedduringsolder- casting. Opticalandscanningelectronmicroscopywereusedtostudy to investigatethemechanismofdiesolderingduringaluminum carried outonsmallsteelcylindersusingpurealuminumand380alloy Two typesoftests,“dipping”testsand“dip-coating”were Bldg. 4508,MS6083,OakRidge,TN37831USA Viswanathan Die SolderinginAluminumCasting 11:35 AM computational thermodynamics. is thedevelopmentofamethodforsystematicalloyrefinementusing FeSi andscriptphase,willbesummarized.Amajorgoalofthisresearch effect ofalloyingelementsonevolutiontheironintermetallics, tions withquenchexperimentswillbepresentedinthistalk.The The UniversityofTennessee, Dept.ofMatl.Sci. and Eng.,Knoxville, : Ren ZhiLi 1 ; 1 Oak RidgeNationalLaboratory, MetalsandCeramics, 1 ; JiunnYuan Huang ASM International:MaterialsScience 1 ; PeterK.Liaw R. O.Ritchie,UniversityofCalifornia, 3 Taiwan PowerCompany, Taipei, Taiwan 100 Location: OprylandConventionCenter Room: CanalA Zhirui Wang, UniversityofToronto, 2 ; JennGwoHuang 1 ; JiJungYeh : QingyouHan 1 ; KenFengChien 3 ; 1 Institute of 1 ; Srinath β 1 - ; work hardeningsolidinsmallscaleyielding.Itisy=a(v the problemofplasticzoneamodeIIIcrackinpowerlaw 0. Thecoordinatesystemthatsatisfiesthisrelationshipisfoundfor particular coordinatesystemsetting radii ofcurvaturethefingerandthumbtrajectories.Givenany Work HardeningSolid Curvilinear CoordinatesforModeIIICrackPlasticZoneina 8:55 AM while thecracksareobservedduringroutinemaintenance. analysis database,theresidualservicelifeofRPVwillbepredicted various potentialsitesundersimulatedloadingconditions.Withthese designs weretestedtocharacterizethecrackingbehaviorofRPVat of thecomplexconfigurationRPV, fatiguespecimensofdifferent specimens, fromwhichinternalflawprofilescanbeinferred.Inview performed toexaminethefractographicfeaturesoffatigue-tested electron microscopy. Scanningelectronmicroscopy(SEM)wasalso front surfaceofaprogressingcrackcanbeobservedbyopticalor mental resultswereusedtoassessthefeasibilityofthismodel.The trum couldbepredictedviatheblockandstatisticalmethods.Experi- these surfacecracksandremaininglifeundertheserviceloadingspec- stress intensityfactorsandtheinitialcrackshape,developmentof ratios wereestimatedbyfiniteelementanalyses.Accordingtothe intensity factorsforsurfacecrackswithdifferentlengthsandaspect rived fromtheexperimentalresults.Meanwhile,aseriesofstress relationship betweencrackgrowthratesandstressintensitieswasde- non-destructive testsorprescribedbyrelatedregulations.AParis-law The initialcrackshape,aninputforthismodel,canbeobtainedby flaw lengthalongtheboundaryofsurfacecrackcouldbedifficult. flaw shapeduringpropagation.However,in-situmeasurementofthe surface crackvariesalongtheflawborder,leadingtoachangein evolving crack.Itisalsoknownthatthestressintensityfactorofa the shapeofaflawandtoestimatestressintensityfactorsfor through cracksinRPVbythismodel,itisnecessarytocharacterize linear elasticfracturemechanics.To predictthepropagationofpart- Design,” amorereliablelifepredictionmodelwasdevelopedbasedon ation. Inthiswork,withadoptingtheconceptof“DamageTolerance closure mechanisms), the ments. However, atR>0.5(beyondtheelimination ofmacroscopic load ratio(orK constant-K 0.96 onthefatiguethresholdinTi-6Al-4V usingbothconstant-Rand work hasfocusedontheinfluence ofloadratiointherange0.1- at veryhighloadratios,R>0.8.For thisreason,recentexperimental enced inturbineenginesunderhigh-cycle fatigueconditionscanoccur 0.1 to0.8.However,“ripple-loading”conditionssuchasthoseexperi- erate loadratios(ratioofminimumtomaximumload)intherange of Typically fatiguecrackpropagationischaracterizedatlowtomod- ley, CA94720USA of Matls.Sci.andMineralEng.,1CyclotronRd.,MS:62-203,Berke- 6Al-4V Influence ofHighLoadRatiosontheFatigueThresholdin Ti- 9:20 AM trajectories. obtained byvaryinguwhileholdingvfixedandviceversaforthumb and risgivenby(v where x,yaremeasuredfromthecracktip,aishalflength 2a{u = (1/R equation to and ε a powerlawhardeningofexponentmthestraincomponentsare nate systemcanbefound(intheory)inwhich solves someantiplaneproblem.Givenaparticularproblemcoordi- strain compatibilityequationis coordinate systemis Inantiplanestrainthestaticequilibriumequationinanycurvilinear versity, Dept.ofMatls.Sci.andEng.,Evanston,IL60208USA problem mustsatisfy: of thecoordinatesystemtrajectoriesthatgivessolutiontoa Here FandTrefertofingerthumbdirectionsR zF =0and σ 4/(1+m) Tz F

: ) ≠ δ 0)reducesto / B. L.Boyce (2ar) δ max F -(1/R δσ ε Tz approaches.AtR>0.5,thevariation ofthresholdwith Tz / -(1-m)/(1+m) ε / 0 δ max =( F +m ) canlargelybeaddressedbased onclosureargu- 2 T /2ar) ) σ δσ δ 1 δ ; R.O.Ritchie Tz / -v δ (1/R δσ σ zF / T itiseasilyshownthattheradiiofcurvature 2m/(1+m) σ : Tz / δ Tz 0 ∆ /R ) F + 4m/(1+m) Johannes Weertman F / 1/m K thresholddecreases linearlywithrespect δ )/ T T + =0.Usingtherelationship . Theequilibriumequation(when +(u δ σ δε F -m zF (2ar) Tz σ /R Tz / 2 δ /2ar) /R 1 F + T σ δ ; + (1/R F zF (1-m)/(1+m) =0andthestraincompatibility 1 =0and 2/(1+m) University ofCalifornia,Dept. δσ ε Tz T )/ Tz /R =1.Afingertrajectoryis / δ δ +[(1-m)/(1+m)](2ar)}, σ T T + T +(1-m)(1/R 1 - zF ; =0and σ δε 1 Tz σ Northwestern Uni- zF Tz

/ ≠ /R δ F 0immediately T - m andR δ u) F 2 =0andthe / σ 2/(1+m) δ ε Tz F zF F

2 )(1/R /R T - ≠ arethe , x=1/ σ 0.For δ zF F =0. 2 =0 / T δ ) = T 2

WEDNESDAY AM 124 Nijhof 1 ; Ramana 1 ; 2 C/85% RH. Under C/85% RH. University of Ala- ° 2 Intel Corporation, CH5- Corporation, Intel Steven W. White Steven W. 1 : ; ; Peter C. Rem 1 1 C/85% RH, near-threshold insta- C/85% RH, near-threshold ° Guy Fredrickson, Reynolds Metals University of Alabama, Dept. of Chem. Eng., 1 Jieping Zhang Jieping Room: Canal C Location: Opryland Convention Center ; 2 : Gerrit H. Nijhof Guy L. Fredrickson, Reynolds Metals Extraction & Processing Division, Light Extraction & Processing : ; Banqiu Wu Delft University of Technology, Mijnbouwstraat 120, RX Mijnbouwstraat Delft University of Technology, 2 2 G. Reddy AL 35487 USA; Box 870203, Tuscaloosa, P.O. Box 870202, Tuscaloosa, bama, Dept. of Metallu. and Matls. Eng., P.O. AL 35487 USA Plasma technology has been around for a long time, but has just recently been used widely for a number of new processes, including the treatment of waste materials. Current investigation includes the manufacturing of magnesium from waste MgO dust using carbon as a reduc- 8:30 AM Introductions and Opening Comments 8:40 AM Metals from for Separation of Non-Ferrous New Techniques Streams Waste Delft 2638 The Netherlands the non-ferrous metals Separation technologies and upgrading of for remelting purposes is a continuous subject of research. Progress has been reported during the previous four session on General recycling of items last years presentation in the Light Metals Conferences. Two San Diego were further investigated in this year: 1)Image analysis of Eddy Current the material separated by the Eddy Current and 2)Wet sorting. Measurements have been performed on the sorting and monitoring of household waste under industrial conditions using image analy- Eddy Current” technology is further developed. Experi- sis. The “Wet ments have been performed on the separation of aluminum and aluminumoxide from dross. In this presentation the actual situation of the running research and the results of recent experiments will be presented. 9:05 AM MgO Dust of Waste Plasma Processing 11:25 AM 11:25 Micro- in Materials in Underfill Propagation Crack Fatigue Packages electronic AZ 85226 USA Blvd., Chandler, Chandler W. 158, 5000 are often ob- during stresses formed in underfill materials Cracks which into traces in the substrate, their propagation served to continue a fracture devices. Hence, failures in microelectronic cause electrical fatigue crack to characterize the technique was used mechanics-based two differ- underfill materials under behavior of different propagation ambient and 85 conditions, i.e., ent environmental in there was a well-defined threshold existing the ambient condition, under 85 each material studied, while growth rate at the near threshold region bility was observed. Crack a period of time during cycling. The near- suddenly increased after believed to be the result of interaction between threshold instability is environment. the materials and the of Materials: Topics General Recycling Metals Recycling Related to Light Sponsored by: Metals Division, Recycling Committee Program Organizers: Muscle Shoals, Laboratory, Smelter Technology Company, OH Toledo, Chrysler, AL 35661 USA; Ilaria Accorsi, Daimler 43606 USA AM Wednesday March 15, 2000 Session Chairs: Shoals, AL 35661 Lab., Muscle Smelter Tech. Company, Dept., MEFOS, New Tech. USA; Christina Viklund-White, Lulea SE-971 25 Sweden Heemsteedse Dreef 92, KN Heemstede 2102 The Neth- Consultancy, erlands; : ; 1 P. Villechaise P. Engineering Sys- : 1 ; 1 Waseda University, Dept. University, Waseda 1 ; 1 F. Lorenzo F. : ; S. Horibe 1 influence on the threshold. influence on ENSMA, Lab. de Mecanique et Physique des ENSMA, Lab. de Mecanique max 1 ; 1 ; E. Fujimagari 1 ; J. Mendez 1 . The possible mechanisms for this behavior include: sustained include: this behavior for possible mechanisms . The max of Matls. Sci. and Eng., 3-4-1 Ohkubo, Shinjuku-ku, Tokyo 169-8555 of Matls. Sci. and Eng., 3-4-1 Ohkubo, Shinjuku-ku, Tokyo Japan Several years ago, it has been found that anelastic behavior is produced in Y-TZP ceramics, i.e., when stress is applied to the specimen the strain is not simultaneously produced but gradually formed abruptly, and after unloading it takes a time to reach the time-dependently, the curious stress-strain hyster- original level. Due to this anelasticity, esis behavior and unusual crack growth behavior were observed. In this paper, the change of stress-strain response during cyclic loading and crack growth under monotonic and cyclic loads in Y-TZP in comparison with those in other kinds of zirconia ceramics were investigated and discussed in terms of time-dependent anelastic behavior and stress- induced phase transformation. tems Inc., 600 Rockmead, Ste. 116, Houston, TX 77339 USA tems Inc., 600 Rockmead, Ste. 116, Houston, and materials developed more than thirty years ago is Technology Normal wear and still in service in the United States and Worldwide. new pipelines have al- tear added to improvements, construction of causing failures by tered and in some cases damaged old pipelines, infinite life otherwise. fatigue in pipeline systems that would have for life prediction This paper contains a review of current theories available theories will under biaxial stresses. The basis for the various and limitations of be discussed with special emphasis on the strengths the various models and techniques to estimate fatigue properties when limited information exists. Data from pipeline rupture case studied by the author will be used to compare life prediction results. Treatment of notches caused by mechanical damage and its effect under biaxial stresses will also be discussed. The paper will also consider the practical limitation of stress based vs. strain based approaches. AM 11:00 Cyclic Deformation and Crack Growth in Zirconia Ceramics M. Matsuzawa Materiaux, Teleport 2, 1 Avenue C.Ader, Chasseneuil, Cedex BP40109 Chasseneuil, Cedex C.Ader, 2, 1 Avenue Materiaux, Teleport France and crack initiation feature were investigated Plastic deformation at steel (316L) cycled in tension compression in an austenitic stainless plastic strain control. For these conditions room temperature under or observed to initiate at Intense Slip Bands different crack types are This paper is focused on crystallographic in twin and grain boundaries. cracks (in PSB), the most frequent microcracks analysis of transgranular of For that a population of some hundred in the air environment. by Each specimen surface area concerned cracks was investigated. by EBSD (Electron Back Scattered these cracks was characterized Then, the knowledge of crystalline orien- Diffraction) measurements. us to identify the tations with regard to the stress axis permitted of the sites for crack activated slip systems in each grain. The nature aspects were studied by initiation was also identified. Crystallographic Firstly the influence of taking into account global or local textures: cyclic behavior and on the global rolling texture of the material on the For that, different total fatigue damage (cracks density) was studied. plat to favor <111>, sampling directions were defined in the rolled slip behavior or other <100> directions corresponding to multiple described in this Differences directions favoring single slip behavior. Concurrently, density. paper concern stress-strain curves and crack and crack initiation the role of local texture on slip band activity and geometric relevant mechanisms was analyzed. Crystallographic then determined. parameters in crack initiation process were 10:35 AM Life Prediction A Review of Practical Application to Fatigue Conditions under Biaxial Stress to K hydride or stress-assisted creep-fatigue induced by (as load cracking focus on will Discussion or static modes. tip closure, near formation), to delineate in the literature evidence work and experimental recent for this K the mechanism Break 9:45 AM 10:10 AM 316L Aus- Crack Initiation in and Fatigue Plastic Deformation Steel: Crystallographictenitic Stainless Aspects M. Mineur

WEDNESDAY AM 125 tics. ian rawmaterialsandtheproblems associatedwiththesecharacteris- unit operationswillbediscussed,as wellasthecharacteristicsofBrazil- gallium marketwillbedescribed in termsofdemandandprices.The oxidation andtextureofthedeposited metalhadtobesolved.The The refineofthemetalisdonevia electrolisis.Specificproblemsof our “homemade”productsuperiortothecommercialsamplestested. described intheliterature.Ithasbeensuccessfulandweconsidernow product. Anefforthasbeendonetosynthesizeresinssimilarthose were alsosuccessfulbutithasbeenimpossibletobuysuch a tractant refusedtosellitus.Ionexchangeresinsselectivegallium successful buthadtobediscontinuedasthemanufacturersof ex- solvent extractionandionexchangehavebeentried.Thefirstonewas high gradegalliumfromBrazilianBayerliquors.Thebasicprocesses of This paperdescribestheeffortdonetodevelopaprocessprovide potential forbecomingagalliumproducerofinternationalexpression. minium industry. AsBrazilisamajoraluminiumproducer, thereis is recoveredasabyproductfromthezincormainlyalu- Thereisnoonedepositofgalliumallovertheworld.Allthismetal Paulo, SP05508-900Brazil Paulo (Epusp),EscolaPolitécnica,Av. Prof.Mello Moraes2373,São Chaves Gallium RecoveryasaBy-ProductofBauxites 10:45 AM 10:20 AMBreak metal ionsfromprocesswastesolutionswouldalsobediscussed. the resultsofourrecentworkoncementationcobaltandother review ofimportantapplicationscementationinhydrometallurgy, streams andtoxicmetalsfromprocesswastewater. Inadditiontothe also beenappliedfortherecoveryofpreciousmetalsfromprocess rity metalionsfromadvancedelectrolytes(product).Themethodhas for theseparation/recoveryoftraceorsmallconcentrationsimpu- tion: Co tation (separation)ofcobaltaccordingtothefollowingchemicalreac- a solutioncontainingzincandcobaltionswouldallowfortheprecipi- progressively dissolves.Forexample,additionofzincmetalpowderin solutions ofitssaltsonamoreelectropositivemetalwhich,inturn, reactions involveelectrochemicalprecipitationofanoblemetalfrom recovery ofmetalionsfromprocesswastesolutions.Cementation Thispaperwouldreviewtheapplicationsofcementationin Rsch. andDev. Div., HawesSt.,Towanda, PA 14848USA mentation ofMetalIonsfromRecovery Process Waste SolutionsbyCe- 9:55 AM ders. compared withthepropertiesofpartsmademoreexpensivepow- moved byvacuumannealing.Mechanicalpropertieswerestudiedand fine-grained structureinsinteredparts.Thehydrogenwasthenre- allowed thermohydrogenprocessingtobeperformedproducea novel loosesinterapproach.Thepresenceofhydrogeninthesystem of CPtitaniumandTi-6Al-4Vwereproducedfromthesepowdersbya cleaned, hydrogenatedandthenmilledtoproducethepowders.Parts were producedfromtheirrespectiveturnings.Turningsinitially Commerciallypure(CP)titaniumandTi-6Al-4Valloypowders Products Inc.,8180BoyleParkWay, Twinsburg, OH44087USA and Adv., 321MinesBldg.,Moscow, ID83844-3026USA; Froes drogen Processing Recycling ofTitanium andTi-6Al-4V Turnings UsingThermohy- 9:30 AM results, aprocessflowsheetwasdeveloped. obtained betweenexperimentalandtheoreticaldata.Basedonthese dynamic andkineticmodelsweredeveloped.Goodagreementwas Rapid quenchingwasemployedtominimizebackreactions.Thermo- recovery wasobtainedwitha48kWpowerinputnitrogenplasma. methods. Experimentalresultsshowedthathighmagnesiummetal enthalpy andimprovedenergyefficiencyoverconventional ing agent.Plasmaenergyisidealforthisreactionbecauseofitshigh 1 ; Valadimir S.Moxson 1 ; AlcídioAbrão 2+ +Zn : Raj P. Singh ° =Co : ° Javaid I.Qazi +Zn 1 1 ; Waldemar Avritscher ; 1 OSRAM SylvaniaInc.,Chem.Dev. Dept., 2 2+ ; . Cementationhasbeenfrequentlyused 1 University ofIdaho,Instit.forMatls. 1 ; OlegN.Senkov 1 ; 1 University ofSão : Arthur Pinto 1 ; FrancisH. 2 ADMA ment Recycling ContaminatedAluminuminaSalt-FreeEnviron- 12:00 PM operations andpotassiumchloridefortificationoftherecycledsalt. operations: minimizingevaporatorheatduty, simplifying evaporator Tennessee. Thispaperidentifiesthreeelementsthat allowpractical plant operatedbyTennessee AluminumProcessorsatMt.Pleasant design, operationandstartupofacommercialscalefluxreclamation flux saltsfromslagwastes.Theauthorssharetheirexperiencesinthe tipping feeswillincreasethenumberofplantswhichopttorecover cal methodsfortheproductionofreclaimedfluxaswellrising very limitedbasisintheUnitedStatesforreasonsofeconomy. Practi- in eliminatingslagwates.Reclaimingsaltfluxhasbeenconductedona reused inthealuminumsmelting.Reclaimingsaltisalogicalfirststep Aluminum Recycling.Slagwastesconsistsofsolublesaltsthatcanbe otherwise environmentallybeneficialandhighlydesirableindustry- Thedisposalofaluminumslagwastescontinuestochallengean Inc., Mt.Pleasant,TNUSA Blvd., Nashville,TN37212USA; 1 cess Design-ProductPerformance Reclaiming SaltFluxfrom AluminumSaltSlagWastes Pro- 11:35 AM baths. a cost-effectivealternativetoperiodicallyreplacinghigh-usagerate ing bathuse.Preliminaryevaluationindicatestheseprocessesmightbe chemical methodstoselectivelyremovemetalsthataccumulatedur- ment workhasshownthatbathslifecouldbeextendedusingelectro- of secondarydeposits,orbymetalsurfacequality. Recentdevelop- Bath lifemayconstrainedbytheetchormillingrate,formation num mayundergosurfacetreatmentinstrongoxidizingacidbaths. Duringmanufacture,metalssuchastitanium,zirconium,andalumi- 1 Strong OxidizingAcidBathRejuvenation 11:10 AM ing practices. thus alsoofferinganeffectiveenergy savingoverconventionalmelt- The heatvalueoftheorganicsubstances isreleasedforuseinmelting, heated, usingtheenergy fromthefluegasesofheatedchamber. ing itanenvironmentallycompatiblesolution.Thescrapchamber is carbonization andsubsequentincinerationofthecontaminants,mak- charged withoutanyrisk.Thisprocessisbasedonlow-temperature dure alsoallowsdampmaterial,orscrapwithwaterinclusions,to be allows chargingoffineturningswithminimalmetalloss.Thisproce- charging fromsillslocatedatbothends.Anelectromagneticpump burners issuitableforingots,pigs,andsows,thusallowingfurnace other scrapofsuchkind.Thechamberheatedbymeansthemain clean andcontaminatedthin-walled,bulk,sheet,thin-walledscrap, ing locatedatthebottomofwall.Thescrapchamberisused for ten metalbathsofbothchambersareinterconnectedthroughanopen- air-cooled wallseparatesthetwochambersfromeachother. Themol- scrap chamberandadirectlyheatedhigh-temperaturechamber. An melting furnaceconsistsoftwo(2)chambers:anindirectlyheated dross accumulationinthebath.Asnameimplies,twin-chamber clude lowenergy&fuelconsumption,minimalmetalloss,andreduced ing technologyandanautomaticchargingmachine.Theresultsin- 150,000 lbs.,inasalt-freeenvironment,usingelectromagneticpump- capable ofprocessingupto18,000lbs./hrwithacapacity lation. Oursolutionconsistsofatwin-chamberedmeltingfurnace, the environment,energyconsumption,metalloss,anddrossaccumu- posed significantproblemsanddifficultieswithmaterialpreparation, oil, grease,paint,orthermalinsulationlayers(rubberplastic)has view. Untilrecently, recyclingofwetor“dirty”scrapcontaminatedby attractive, fromeconomicalaswellanenvironmentalpointsof resources havemadetherecyclingofaluminumscrapincreasingly Risingenergypricesandtheworldwidecrisisofavailablenatural Canonsburg, PA 15317USA Richard M.Russell&Associates,LLCConsultingEng.,2003Blair Ch2m Hill,P.O. Box91500,Bellevue,WA 98009USA : Donald M.Martosko 1 ; 1 LOI Inc.,333Tech. Dr., Ste.109, : 2 Tennessee AluminumProcessors Richard Russell : James D.Mavis 1 ; JerrySweeny 1 2 ; ;

WEDNESDAY AM 126 ; : 2 Juergen M. Lawrence Ber- : 1 ; 1 ; Stephen M. Foiles 1 Technion, Dept. of Matls. Technion, 2 University of Oxford, Dept. of 1 pure tilt character. These films pure tilt character. ° ; 2 ; Urlich Dahmen 1 ; Wayne E. King ; Wayne 1 about a common <110> axis. The misorientation about a common <110> Tamara Radetic Tamara ° ; Dan Schectman 1 : ; Geoffrey H. Campbell ; Geoffrey 1 Lawrence Livermore National Laboratory, Chem. & Matls. Sci. Di- Lawrence Livermore National Laboratory, Sandia National Laboratories, Comp. Matls. Sci. Dept., Mailstop 9161, Plitzko 1 Box 808, Livermore, CA 94550 USA; rect., Mailstop L-370, P.O. 2 Box 969, Livermore, CA 94550 USA P.O. The Sigma 5 (310)/[001] symmetric tilt grain boundary (STGB) has been investigated in four different fcc metal systems. The metals chosen include pure aluminum, pure copper, aluminum with 1 at.% These model grain boundaries and copper with 1 at.% silver. copper, have been fabricated by ultra-high vacuum diffusion bonding of precisely oriented single crystals. The atomic structure of these STGBs Eng., Haifa, Israel by CVD techniques Thin films of diamond grown on Si substrates using a microscopy, have been investigated by high resolution electron were prepared by re- JEOL 4000EX electron microcsope. Specimens milling. Most grains in moval of the Si substrate followed by Ar+ ion with additional twin the films showed heavy twinning on {111} planes, Five-fold twin centres were found structures of increasing complexity. in many grains, and it is shown that these centres give rise to incoherent, high-order twin boundaries. The core structure of the five-fold twin centre is shown to be a planar C5 ring, a stable ring configuration of sp3 carbon atoms. The implications of the twin structures on crystal growth processes will be discussed, and it will be shown that the first-order twin boundaries are essential for fast crystal growth, and give rise to many of the features that are observed on the macroscopic scale. AM 11:20 Substitutional Impurity Segregation to the Sigma 5 (310)/[001] Symmetric Tilt Grain Boundary in Fcc Metals A few applications of high-resolution transmission electron mi- electron transmission of high-resolution few applications A will be materials dissimilar between of interfaces to the study croscopy semiconduc- ceramic/ceramic, include metal/ceramic, These discussed. addition In interfaces. and semiconductor/ceramic tor/semiconductor formation of dislocations, the defects such as misfit to interfacial the resulting on a substrate, and during deposition different variants In particular, will be considered. between these variants planar defects transforma- that occur during phase focus on interfaces the talk will at the inter- and look in detail bandgap semiconductors tions in wide a phase transformation. that occur during mediate phases 10:00 AM on of Interfaces in Thin Films of Au Structure and Morphology Ge Substrates Micro., Matls. Sci. for Elect. Nat. Ctr. keley National Laboratory, CA 94720 USA 72, 1 Cyclotron Rd., Berkeley, Bldg. Div., on films have been grown epitaxially {110} Au mazed bicrystal physical vapor deposition. There are only two {001} Ge substrates by variants in the film, resulting in a “mazed equivalent orientation made of many grains in only two orienta- bicrystal” microstructure tions, rotated 90 is while the inclination (grain boundary plane) between grains is fixed, in- are perpendicular to the film/substrate variable. Grain boundaries terface and are therefore are of 90 on the structure have been annealed in situ and the effect of annealing with the substrate and morphology of grain boundaries and interfaces high resolution electron has been investigated by conventional and The stability of particular grain boundary inclinations microscopy. their atomic structure during grain coarsening has been examined and that during annealing has been studied by HREM. It has been observed diffusion induced grain interdiffusion at the Au/Ge interface leads to instabilities at boundary migration in the film as well as morphological structure of the Au/ the Au/Ge interface. The evolution of the atomic by HREM. This Ge interface with annealing has been characterized Energy Research, Office work is supported by the Director, Office of Division of the U.S. of Basic Energy Sciences, Materials Sciences Department of Energy under Contract No. DE-ACO3-76SFOOO98. 10:30 AM Break 10:50 AM Invited in CVD Diamond HREM Studies of Interfaces and Boundaries John Hutchison Matls., Parks Rd., Oxford OX13PH UK; Al) 3 David Pirouz : : GKSS Research 1 ; 1 Fritz Appel : Diane E. Albert, Los Alamos National Los Alamos Diane E. Albert, Room: Canal D Convention Center Location: Opryland Martin A. Crimp, Michigan State University, Martin A. Crimp, Michigan Structural Materials Division, Physical Materials Division, Structural Case Western Reserve University, Matls. Sci. and Eng., 510 Reserve University, Case Western 1 Arizona State University, Dept. of Phys. and Astro., Tempe, Dept. of Phys. Arizona State University, 1 ; 1 ; 1 White Bldg., CWRU, 10900 Euclid Ave., Cleveland, OH 44106-7204 White Bldg., CWRU, 10900 Euclid Ave., USA Centre, Instit. for Matls. Rsch., Max-Planck-Strasse, Geesthacht D- 21502 Germany Titanium aluminides with compositions slightly lean in Al are presently being considered for engineering applications. Phase equilibria and transformation in these alloys lead to the formation of a lamellar microstructure comprising of the intermetallic phases alpha 2(Ti Pirouz and gamma (TiAl). This morphology has received much attention since nearly all mechanical properties of g-base alloys are improved when the materials contain a significant volume fraction of lamellar colonies. Several aspects of deformation and fracture might be associated with mismatch structures and coherency stresses of lamellar interfaces. In the present study these structural features will be examined by detailed transmission electron microscopy observations involving in situ heating studies and high resolution imaging techniques. The implications of interface related processes will be discussed with respect to strengthening phenomena and the structural stability of lamellar materials. 9:30 AM A Few Applications of HRTEM to Hetero-Interfaces 8:30 AM Invited Interfaces HREM Characterization of Hetero-Epitaxial AZ 85287 USA based on two (or more) There is much current interest in structures associated with achiev- dissimilar materials but there are many problems lattice mismatch, which ing heteroepitaxial growth. In addition to formation, valence mis- invariably causes strain and possible defect are factors that can seri- match and differences in thermal expansion can be grown. Charac- ously impact the quality of the materials which addition to close interac- terization of microstructure using HREM, in role in optimizing the tion with the crystal grower, can play a valuable three systems of consid- growth process. This talk will concentrate on a) heterostructures based erable scientific and industrial importance: of band-gap engineer- on SiGeC/Si, which offer the intriguing prospect substrates, which could ing in a lattice-matched system; b) CdTe/Si with MCT (mercury allow the monolithic integration of Si electronics alloys of Group III-ni- cadmium telluride) infrared detectors; and c) microelectronics and op- trides, which could totally revolutionize the toelectronics industries. 9:00 AM and Fracture in Interface-Related Phenomena of Deformation Aluminides Titanium Two-Phase Smith Sponsored by: Sponsored Committee Metallurgy Program Organizers: High Resolution Electron Microscopy Electron Resolution High Interfaces Science: in Materials AM Wednesday Laboratory, MST-6, The Metallurgy Group, Los Alamos, The Metallurgy MST-6, Laboratory, Allen Crimp, Michigan State NM 87545 USA; Martin of Materials Science and Mechan- Department University, 48824-1226 USA; John E. Smugeresky, ics, East Lansing, MI Department 8724, Livermore, Sandia National Laboratories, CA 94551-0969 USA March 15, 2000 Session Chair: Dept. of Matls. Sci. and Mech., East Lansing, MI 48824-1226 Dept. of Matls. Sci. USA

WEDNESDAY AM 127 7405-Eng-48. Lawrence LivermoreNationalLaboratoryundercontractnumberW- under theauspicesofUnitedStatesDepartmentEnergyand dependence oftheinteratomicinteraction.Thisworkwasperformed boundaries canbeunderstoodintermsofthestrengthangular Generalized PseudopotentialTheory. Thediffering structuresofthese gularly dependentinteractions,suchasthosedevelopedwithinModel atomistic simulationsusinginteratomicpotentialsincorporatingan- structures. Thestructuresoftheseboundarieshavebeenmodeledwith croscopy. Theboundarieshavebeenfoundtodifferent atomic have beendeterminedbyhighresolutiontransmissionelectronmi- precisely orientedsinglecrystals.Thestructureoftheseboundaries three different BCCmetals(Nb,Mo,andTa) bydiffusion bonding the identicalSigma5(310)/[001]symmetrictiltgrainboundaryin critical testforinteratomicpotentials.To thatend,wehavefabricated tures thanFCC.We havefoundthatgrainboundarystructureisa atomistic simulationsofmaterialswithmorecomplicatedcrystalstruc- tronic structureondefectstructuresisakeyingredientforsuccessful prising thecrystal.Understandingandmodelinginfluenceofelec- aries canbeinfluencedbyelectroniceffects,i.e.theelementcom- However, foragivencrystalstructure,thestructureofgrainbound- boundaries isthecrystalstructureofmaterial,e.g.FCCvs.BCC. Thedominantfactorindeterminingtheatomicstructureofgrain Mailstop 9161,P.O. Box969,Livermore,CA94550USA CA 94550USA; ratory, Chem.&Matls.Sci.,MailstopL-356,P.O. Box808,Livermore, Moriarty als Electronic EffectsonGrainBoundaryStructureinBCCMet- 11:40 AM Contract W-7405-Eng-48. der theauspicesofUnitedStatesDepartmentEnergyunder work wasperformedatLawrenceLivermoreNationalLaboratoryun- tal resultsarediscussedandcomparedtothetheoreticalmodel.This tion ofthrough-focalserieshavebeenused.Finally, theseexperimen- at theinterface,HREMcoupledwithimagesimulationandreconstruc- quantified. To determinetheatomicpositionsofsegregatedatoms amounts ofthesegregatedspeciesatgrainboundaryhavebeen Philips CM300-FEGequippedwithanimagingenergy filter. The HREM imagesandanalyticalmeasurementswereperformedusinga microscopy havebeenusedtovalidatethetheoreticalmodels.The transmission electronmicroscopy(HREM)andanalytical Ag atomssegregatetodistinctsitesattheinterface.Highresolution retical calculationsoftheinterfacestructureindicatethatCuand ture calculationswithintheLocalDensityApproximation.Thetheo- tials basedontheEmbeddedAtomMethodandwithelectronicstruc- has beenmodeledwithatomisticsimulationsusinginteratomicpoten- : Geoffrey H.Campbell 1 ; StephenM.Foiles 2 Sandia NationalLaboratory, Computat.Matls.Sci., 1 ; Wayne E.King 2 ; 1 Lawrence LivermoreNationalLabo- 1 ; JamesBelak 1 ; JohnA. Steels A HistoryofthePatentingandLicensingUltrahigh-Carbon 9:00 AMInvited under ContractW-7405-Eng-48. Department ofEnergybyLawrenceLivermoreNationalLaboratory materials. ThisworkwasperformedundertheauspicesofU.S. containing laminatesisgiven,andparallelsaredrawnwithancient paper, asummaryofthemoderndevelopmentUHCSandUHCS- both ancientandmoderntimesinlaminatedcomposites.Inthepresent tion. Inadditiontomonolithicproducts,UHCShavealsobeenusedin and inparticular,DamascusSteels,havereceivedconsiderableatten- nections betweenthemodernUHCSandtheirancientcounterparts, logical periodofdevelopment(from1975tothepresent).Thecon- history (datingbackto~300BC)andaninteresting,recent,techno- and nowknownasultrahighcarbonsteels(UHCS),havebotharich Hypereutectoidsteelscontainingbetweenabout1and2.1wt%C, 808, L-001,Livermore,CA94550USA 1 mids, toAlexandertheGreat, toY2K The EvolutionofUltrahigh-CarbonSteels-FromtheGreatPyra- 8:30 AMKeynote Matls. Instit.,Austin,TX78712-1063USA Session Chair: March 15,2000 Wednesday AM Materials EngineeringDivision,Livermore,CA94550USA Lawrence LivermoreNationalLaboratory, Manufacturing& Laboratory, Livermore,CA94550USA;CholK.Syn, 1063 USA;DonaldR.Lesuer, LawrenceLivermoreNational Mechanical EngineeringDepartment,Austin,TX78712- Program Organizers: als Committee,ShapingandFormingCommittee Processing andManufacturingDivision,StructuralMateri- Sponsored by: Steels Oleg D.Sherby:Ultrahigh-Carbon Honorary SymposiumforProfessor The extrudedUHCSs weretestedintensionatboth ambientandinter- ate temperatures, 650to820 Ultrahigh-carbonsteels(UHCSs) arereadilyextrudedatintermedi- sity, Matls.Sci.andEng.,Stanford, CA94305USA Lewis ResearchCenter,Cleveland, OH44135USA; National Laboratory, L-342,Livermore, CA94551USA; 1 Syn truded atIntermediateTemperatures Superplasticity andStrengthofUltrahigh-CarbonSteelsEx- 9:20 AMInvited Carbon Steels. to thefutureconsiderapplicationsandopportunitiesforUltraHigh as thecreationofsteelminimillsisconsideredtobe.We willthenlook plore theideaofUltraHighCarbonSteelsasadisruptivetechnology, inventions ofProfessorOlegSherbyandhiscolleagues.We willex- the patentedtechnologiesandreviewlicensinghistoryof the ing newmaterialsintocommercialmarkets.Thispaperwilldescribe some interestingstoriesanddemonstratesthedifficultiesinintroduc- yet reachedlargescalecommercialuse,butthelicensinghistoryhas many years,orsometimesdecades.UltraHighCarbonSteelshave not commercially significantandtheroadtocommercialsuccessmaytake Onlyasmallnumberofdiscoveriesmadeatuniversitiesbecome Licen., 900Welch Rd.,Ste.350,PaloAlto,CA94304USA Lawrence LivermoreNationalLaboratory, Director’s Off., P.O. Box WESGO Metals,Belmont,CA94002 USA; 2 ; DonaldR.Lesuer : Jon C.Sandelin Structural MaterialsDivision, Eric Taleff, TheUniversityofTexas, TX 2 Location: OprylandConventionCenter Room: BayouE ; J.DanielWhittenberger Eric M.Taleff, UniversityofTexas, 1 ; ° C, intoroundbars andT-shapesections. 1 Stanford University, OfficeofTech. : Toshi Oyama : 2 Jeffrey Wadsworth Lawrence Livermore 3 ; OlegD.Sherby 4 Stanford Univer- 1 ; CholK. 3 NASA- 1 4 ; ;

WEDNESDAY AM 128 Univer- 1 ; 2 John William : ; Marvin L. Cohen 2 University of California, Dept. of Phys., 2 Patrice E.A. Turchi, Lawrence ; David Roundy Room: Johnson A/B Location: Opryland Convention Center 1 Kazuhiro Otsuka, University of Tsukuba, Structural Materials Division, Electronic, ; Chris R. Krenn 1 Instit. of Matls. Sci., Tsukuba, Ibaraki 305-8573 Japan; Instit. of Matls. Sci., Tsukuba, Alphonse Finel, ONERA/CNRS, LEM, BP72 Chatillon, Cedex, France Morris Sponsored by: Alloy Phases Magnetic & Photonic Materials Division, Committee Program Organizers: Materials Science and Livermore National Laboratory, Division, Livermore, CA 94551 USA; Antonios Technology Livermore, Gonis, Lawrence Livermore National Laboratory, CA 94551-0808 USA AM Wednesday March 15, 2000 Session Chairs: 8:30 AM Invited Mechanical Stability and the Limits of Strength Evans Hall, Dept. of Matls. Sci., 555 sity of California-Berkeley, CA 94720 USA; Berkeley, CA 94720 USA Berkeley, The upper limit of strength (the “theoretical strength”) has been an active subject of research and speculation for the better part of a The subject has recently become important, for two reasons. century. First, given recent advances in ab initio techniques and computing machines, the limits of strength can be calculated with considerable mechanical making this one of the very few problems in accuracy, behavior that can actually be solved. Second, given recent advances in materials engineering, the limits of strength are being approached in some systems, such as hardened or defect-free films, and their rel- evance is becoming recognized in others, including hard coatings, carbonitrides and diamond-cubic crystals. An elastically strained solid it is always at least metastable. Given a kinetically plausible pathway, delay dynamic recrystallization by pinning the grain boundaries. Large boundaries. the grain by pinning dynamic recrystallization delay thus en- region, surrounding in the density raise dislocation carbides slowing ductility by reduce Fine carbides of DRX. nucleation hancing and concentrations cause stress carbides large DRX, whereas and DRV high tempera- are stable up to quite steels, the carbides cracks. In tool strength in tendency for cracking, considerable increase tures causing the fine C steels. In HSLA steels, energy compared to and activation of the hot at the low end carbonitrides tend to precipitate microalloy activation strength and the apparent which raises the working range, austenitic phase For steels with an lowering the ductility. while energy carbides and ductility, carbon enhances DRV in which the dissolved the strength and decrease ductility on coding to considerably raise the in steels are stronger and less ductile than those ferritic phase. Pearlitic however, they show considerable work the spheroidized condition; spheroidizes during hot working. By suitable softening as the pearlite the high carbon steels can be produced thermomechanical processing, In capable of superplastic deformation. with a micro-duplex structure large alloy carbides slow interpass recrys- multistage rolling schedules, refinement at the hot end. In contrast, fine tallization and hence grain delay it at the cool end, resulting in pancaked microalloy carbonitrides yield a fine ferritic grain structure. austenitic grains which Discussion AM Round Table 11:20 Steels-What does From Damascus Steels to Ultrahigh-Carbon the past reveal of future applications? Moderator: George Mayer Symposium; Hume Rothery Award and Evolution Phase Transformations in Materials: Session IV : ; 2 The 1 ; 3 Hugh J. : C resulted in austenite ° Case Western Reserve Case Western 1 ; Oleg D. Sherby : Alberto Fernandez temperature. The results temperature. 1 1 ; 1 Stanford University, Matls. Sci. and Stanford University, Concordia University, Mech. Eng. H Concordia University, 3 1 ; Eric M. Taleff ; 2 2 C). ° C immediately prior to austempering. It was found C immediately prior to John J. Lewandowski ° University of Wollongong, Matls. Eng., Wollongong, University of Wollongong, 1 : Oscar Ruano ; ; 1 2 ; C. A.C. Imbert University of the West Indies, Mech. Eng., St. Augustine, University of the West 1 2 Centro Nacional de Investigaciones Matalurgicas, Av. de Gregorio del de Gregorio Av. Centro Nacional de Investigaciones Matalurgicas, Trinidad Carbides have a strong influence on the hot working behaviour of hardness and the steels depending on their size, distribution, solubility, matrix, either austenite or ferrite. Fine carbides pin dislocations slow- and despite the higher dislocation density ing dynamic recover (DRV) 54934, 1455 de Maisonneuvre Blvd. W., Montreal, Quebec H3G1M8 54934, 1455 de Maisonneuvre Blvd. W., Canada; University, Dept. of Matls. Sci. and Eng., 10900 Euclid Ave., Univ. Dept. of Matls. Sci. and Eng., 10900 Euclid Ave., University, Circle, Cleveland, OH 44016 USA This presentation will provide a review of the microstructural features which affect the cleavage fracture stress in fully pearlitic steels. Data has been obtained over a wide range of test temperatures on a variety of steels where the pearlite interlamellar spacing, prior austenite grain size, and pearlite lamallae thickness have been varied. The effects of such changes on the magnitude of the cleavage fracture stress will be reviewed. AM 11:00 of Steel Influence of Carbides on the Hot Working Amo 8, Madrid 28040 Spain; Tara Chandra Tara 2 Eng., Stanford, CA 94305-2205 USA ultrahigh-carbon steel (UHCS) alloys have been thermal-me- Two The first alloy chanically processed to obtain various microstructures. weight percent, and the contains 1.3 C, 0.5 Mn, 0.6 Si, and 0.18 Cr in 0.09 Cr and 0.31 Mo in second alloy contains 1.5 C, 0.75 Mn, 0.23 Si, by processing include weight percent. The microstructures developed pearlite of sev- fine-grained spheroidite, coarse-grained spheroidite, martensite. Unique eral different interlamellar spacings, and tempered described for producing thermal-mechanical processing procedures are from the same fine- several of these microstructures in each alloy The fracture alloy. grained spheroidized material of the respective microstructure have been toughnesses of both UHCS alloys with each samples. The effects experimentally determined using chevron-notch toughness are pre- of microstructure and alloy content on fracture trends in the behavior of sented and discussed in light of more general UHCS materials. 10:40 AM Invited Microstructural Effects on the Cleavage Fracture Stress of Pearlitic Steels McQueen 9:40 AM Iron of Austempered Ductile Processing Thermomechanical that in general deformation increased the transformation kinetics dur- that in general deformation the alloyed ductile irons with high manganese ing austempering. For on resulted in a significant reduction levels (>0.3%), the deformation the the deleterious unstabilised austenite in the volume fraction of 30% reduction at 900 intercellular regions. The NSW 2522 Australia of both unalloyed and alloyed duc- High temperature deformation under uni axial compression at an austenitisation tile irons was carried out temperature of 900 mediate temperatures. At ambient temperature, all extruded UHCSs extruded all temperature, At ambient temperatures. mediate than of more tensile strength (ultimate strength high tensile showed of over (elongation-to-failure elongation with outstanding 700 MPa) was ob- behavior superplastic temperatures, At intermediate 30%). the A UHCSs extruded below served in the extrusion data on high-temperaure with other published are compared (900 to 1100 of UHCSs recrystallization. The refined grain struc- grain refinement by dynamic more nucleation sites for the bainitic ferrite ture in turn provided the transformation kinetics during formation and thus accelerating the austempering process. 10:00 AM Break 10:10 AM Keynote of Ultrahigh-Carbon Steel: Pearlite, Toughness Fracture Martensite and Tempered Spheroidite, Manolo Carsi 78712-1063 USA; TX Matls. Instit., Austin, TX University of Texas,

WEDNESDAY AM 129 NM 87545USA; Alamos NationalLaboratory, MST-8,MailStopG755,LosAlamos, in thelowsymmetry phase. enhancement ofthermal fluctuationsandanoveltype ofwallwetting the localstructuralrelaxationenergy. Their appearanceleadstoan elastic compatibilityrule,theformer donot.Insteadtheyminimize are foundinadditiontotraditional twinwallswhilethelaterobey monoclinic transitionincordierite. Topological twin-typestructures systems whichwillbediscussed.A notableexceptionisthehexagonal- nate themicrostructuralevolution inthevastmajorityofchemical lar dynamicsmethods.Theelastic,long-rangingcorrelationsdomi- ordering treatedbyMonteCarloandstructuralrelaxationsmolecu- computer simulationsarebasedonahybridemethodwithatomic tic successionoftweed,tartan,needle,comb,andstripepatterns.The transition pointleadsincontinuousphasetransitionstoacharacteris- scale computersimulations.Quenchingasamplethroughferroelastic structures inframeworkiscomparedwithresultsoflarge Theexperimentallyobservedtimeevolutionofferroelasticmicro- Cambridge CB23EQUK H. Salje Time EvolutionofMicrostructuresinFerroelastics 10:00 AMInvited Basic EnergySciences. ishes). Work supportedbytheU.S.DepartmentofEnergy, Office of between thehydrogenationanddehydration‘plateau’pressuresvan- temperature wherethehysteresisdisappears(wheredifference the hysteresisandallowsonetocalculatecriticalpressure therms. Theproposedtheorypredictsthetemperaturedependenceof hysteresis inthepressure‘plateaux’ofpressure-compositioniso- metal/hydrogen systemsandexplainsquantitativelytheubiquitous atoms areconsidered.Thetheoryisappliedtothedecompositionof solid isinequilibriumwithfiniteandinfinitereservoirsofinterstitial ther, two-phasecoexistanceisnolongerpossible.Thecaseswherethe which isafundamentalrequirementofGibbsthermodynamics.Fur- by thermalfluctuations.Asaresult,thesystemloosesergodicity, barrier locksthesysteminmetastablestatesthatcannotbesurmounted a macroscopicenergybarrierbetweenthetransformingphases.This ventional thermodynamicsofthephasetransformationbyproducing concentration. Itisshownthatthecoherencystrainchangescon- interstitial atomsintotwocoherentphasesofdifferent We developatheoryforthedecompositionofsolidcontaining Piscataway, NJ08855-0909USA Interfaces Thermodynamics ofOpenTwo-Phase SystemswithCoherent 9:30 AMInvited Materiel Command,USAF, underGrantNo.F49620-96-1-0454. support oftheAirForceOfficeScientificResearch, symmetry willbeemphasized.Theauthorsacknowledgethefinancial scribed. Throughoutthetalk,utilizationoftheorymagnetic introduced andvariousphasetransitionsbetweenthemwillbede- magnetic materials.Somelesscommontypesofmagnetismwillbe lattices willbeutilizedtodescribethemagneticsymmetryofvarious presented. Magneticsymmetryoperations,pointgroups,andBravais Anoverviewofsomestructuralaspectsmagneticorderingwillbe PA 15213-3890USA Mellon University, Matls.Sci.andEng.,5000ForbesAve., Pittsburgh, Laughlin Magnetic Ordering:SomeStructuralAspects 9:00 AMInvited expected tobeimportant. and discussestheexperimentalsituationsinwhichtheyareknownor reviews abinitiocomputationsforanumberofmetalsandcompounds, shows howthoselimitsreflectthesymmetryofstrainedlattice, defines thelimitsofelasticstability(whicharesurprisinglysubtle), namic instabilitysetstheupperlimitofstrength.Thepresentpaper commence atthelimitofstabilityelasticstate.Thisthermody- criteria. Itcanbenucleated(andordinarilyis)but,failingthat,must structural phasetransformationwhoseonsetisgovernedbytheusual or intoanewphaseentirely. Inthatsense,plasticdeformationisa will spontaneouslytransformintoashearedorbrokenreplicaofitself 1 ; 1 ; MatthewA.Willard : 1 University ofCambridge,Dept.EarthSci.,DowningSt., Ricardo B.Schwarz 2 Rutgers University, Dept.Mech.andMatl.Sci., 1 ; MichaelE.McHenry 1 ; ArmenG.Khachaturyan : : 1 ; Ekhard K. David E. 1 Carnegie 2 ; 1 Los gory B.Olson Potency ofHeterogeneousMartensiticNucleationSites 11:45 AM Invited under stress. the transformationkineticsobservedwhenoccurs mation plasticitydeformation.Thisanalysisisthenabletoexplain applied stressfortheplateorientation,givingthusagreatertransfor- laxation byplasticdeformationleadstoalargerefficiencyof the increases, andatthebeginningoftransformation.Thestress re- and lowappliedstresses)toasingleorientationwhenthestress the platearrangementismodifiedfromselfaccommodating(for no ering elasticandelastoplasticbehaviourofthephases.Itisshownthat the appliedstressesandinternalhasbeenanalysedconsid- been establishedusingfiniteelementmodelling.Therespectiveroleof analyse theeffectofstress,asimplemicromechanicalmodelhas rence ofplasticdeformationintheparentphase.Inordertofurther occurrence ofachangeinthestressrelaxationprocess,i.e.occur- stress. Basedontheoreticalanalysisthisincreasecanbelinkedtothe indicating thatafurthergrowthofthethinplateisallowedunder plate morphologyisobserved.Thewidthoftheincreased, tion plasticitydeformationincreases,asimultaneouschangeinthe the mechanicalpropertiesofparentaustenite.Whentransforma- dent onthelevelofappliedstress,transformationprogressand case offerrousalloys.Thecontributioneachmechanismisdepen- of thetransformationstraininstressdirectionareoccurring entation ofthemartensiticplates,anisotropicplasticaccommodation major mechanismsresponsiblefortransformationplasticityi.e.ori- plasticity deformationinFe-Ni-Calloyshaveshownthatthetwo cannot bedisregarded.Experimentalmeasurementsoftransformation tion itselfhavealargecontributiontotheobservedphenomenaand interesting toconsiderbecausestressesgeneratedbythetransforma- than theyieldstressofparentaustenite.Sucharangeis for stressesrangingfromlowexternaluptolarger dependent onthelevelofappliedstress.We considerthebehaviour These modifications,whichhavetobeanalysedsimultaneously, are kinetics ofthetransformationandmorphologyplates. transformation inducedplasticityisobserved,asamodificationofthe Whenmartensitictransformationoccursunderexternalstresses,a CNRS 7584,ParcdeSaurupt,Nancy, Cedex54042France Elastic Constants Premartensitic PhenomenainTi-Ni-BasedAlloysSeenthrough 10:45 AMInvited 10:30 AMBreak straint onthenonlinear elasticcontinuum,which fixestheBurger’s the dislocationsare modeledbytheimpositionof atopologicalcon- a multiple-minimum,Landau-Ginzburg typepotentialenergy, while The nonlinearityofthemodelsystem resultsfromtheimpositionof tion structuresarestudiedinthe contextofMartensiticnucleation. Thenonlinear,nonlocalcontinuum elasticfieldsofvariousdisloca- Sci. andEng.,2225N.CampusDr., Evanston, IL60208-3108USA Elisabeth MarieGautier Martensitic Transformation underStress inFerrous Alloys 11:15 AMInvited and thesubsequentmartensitictransformations. only cÕbutalsoc44,andthecorrelationbetweenelasticsoftening formations. Attheconferencewewillshowimportanceofnot A=c44/cÕ behaveddifferentlydependinguponthetypesoftrans- shear. However, thetemperaturedependenceofanisotropyfactor temperatures, wherec44representstheresistanceto{001}<100> ited softeningwithdecreasingtemperaturetowardthetransformation B19-B19Õ andB2-Rphase-B19Õ.Inallcases,bothcÕc44exhib- pending uponcompositionandheat-treatment.i.e.B2-B19Õ,B2- loys, whichexhibitthreetypesofmartensitictransformations,de- systematic elasticconstantsmeasurementofvariousTi-Nibasedal- {110}<110> shear. Inthepresentpaperwewillreportaresultof softening ofelasticconstantcÕ,whichrepresentstheresistanceto attention inrecentyears.Inthesestudieswaspaidtothe Premartensiticphenomenainb-phasealloysattractedconsiderable 8573 Japan Tsukuba, Instit.ofMatls.Sci.,Tennodai 1-1-1,Tsukuba, Ibaraki305- 1 ; Andrew C.E.Reid : Kazuhiro Otsuka 1 ; 1 Ecole desMinesdeNancy, LSG2MUMR 1 ; 1 ; XiaobingRen 1 Northwestern University, Matls. 1 ; 1 University of : Gre- :

WEDNESDAY AM 130 ; ’ 2 γ Los 1 Uni- 2 ; 1 Ralph E. ; David M. ; Robert D. : 1 1 ’ age hardening γ ; Hywel A. Davies 1 ) process has been used has been ) process  Sandia National Laborato- 2 ; Patrick G. Dickerson 1 processing has produced yield has processing ; Iver E. Anderson  2 304L material, including grain size, 304L material, including Patrick W. Hochanadel Patrick W.  : (Al,Ti). It is used primarily in the chemical 3 ; Joe C. Fonseca 1 Ayodele Oladimeji Olofinjana Ayodele Queensland University of Technology, Schl. of Mech. Queensland University of Technology, 1 processed 304L had a yield strength of 45-50 KSI 304L had a yield strength processed :  to the mechanical properties. processed 316 SS and ; 2  ; John E. Smugeresky 1 Iowa State University, Ames Lab. Usdoe, Metallu. and Cer., Ames Lab. Usdoe, Metallu. Iowa State University, 1 ; 3 Optomec, R & D, 2701-D Pan American Freeway, Albuquerque, Optomec, R & D, 2701-D Pan American Freeway, ; Gary K. Lewis 3 1 Keicher James H. Kern Manu. and Med. Eng., Gardens Point 4001, Brisbane, Australia; precipitates of ordered Ni 104 Wilhelm Hall, Ames, IA 50011 USA; NM 87107 USA The flexibility with regard to local alloy composition offered by the freeform laser cladding process make this technique potentially viable for the production of net shape parts with spatially distributed microstructural properties. Such microstructural control requires in-situ alloying through simultaneous laser-melting and deposition of multiple binary and ternary alloys of pure-metal powders. In the current study, Cu, Ni, Sn, and Al are produced using this technique. The coupled effects of alloy composition and laser velocity are investigated, and process limits for producing structurally and chemically inhomogeneous components are determined. The primary microstructural features of interest include solidification structures, local composition distributions, and defects. Research avenues for continued advancement are suggested. This work is supported by USDOE Basic Energy Sciences under contract number W-7405-Eng-82. 9:50 AM Multi-Stream Casting of Ultra High Strength Sub-Millimeter Diameter Wire The Laser Engineered Net Shaping (LENS Net Laser Engineered The smaller metals. The variety of of a freeform samples solid to fabricate LENS from the size resulting grain a This represents in 316 SS. MPa) KSI (385-480 of 56-70 strengths annealed 316 of conventional, over the properties two-fold increase have also on 304L SS Recent experiments in ductility. with no loss than in 316 but, to a lesser degree increased yield strength; produced an SS. The LENS and ~65 to the build layers, when tested perpendicular (310-345 MPa) The micro- to the build layers. when tested parallel KSI (450 MPa) LENS structural features of the and dislocation densities, will be related to that second phase particles of the LENS contract under U. S. Department of Energy supported by the Work DE-AC04-94AL85000. 9:10 AM of Laser Deposited and Wrought Microstructure and Properties Alloy K-500 (UNS N05500) Field MS Box 1663, P.O. MST-6: Metallu., Alamos National Laboratory, 87545 USA G770, Los Alamos, NM N05500) is a corrosion-resistant nickel-copper Alloy K-500 (UNS form alloy that contains aluminum and titanium to fasteners, pump shafts process, marine, and oil/gas industries as tubing, known as Directed and impellers, etc. The laser deposition process fully dense specimens of Light Fabrication (DLF) was used to produce and mechanical property Alloy K-500 for metallographic inspection K-500 was obtained. A analysis, and the wrought counterpart of Alloy all specimens, and me- series of heat treatments was performed on of aging time and aging chanical properties were recorded as a function were analyzed at various temperature. In addition, the microstructures of the mechanical aging times and temperatures. A direct comparison wrought product demon- properties between the laser material and the The kinetics of aging strated that similar properties could be obtained. were investigated by both the wrought and laser deposited Alloy K-500 determination of the utilizing the mechanical properties data, since times in aging (i.e., precipitate size proved to be difficult at early the kinetics of aging before coarsening). The methodology to study (JMAK) kinet- was similar to the Johnson-Mehl-Avrami-Kolmogorov the mechanisms of ics approach, and from the results of this analysis, K-500 at early aging aging in both wrought and laser deposited Alloy times are presented and discussed. 9:30 AM Processing In-Situ Alloying Using Freeform Laser Napolitano ries; ; S. 1 ; Frank 1 K/s, the 4 ; Guleid N. 1 ; B. P. Somerday ; B. P. 1 ; Joe C. Fonseca Processed 304l Stain- 1      Dan J. Thoma : ; Bryan R. Lally 1 ; J. E. Smugeresky 1 Sandia National Laboratory, Livermore, CA Sandia National Laboratory, David L. Bourell, University of Texas, David L. Bourell, University 1 Location: Opryland Convention Center ; 2 Materials Processing and Manufacturing Materials Processing Srinath Viswanathan, Oak Ridge National Srinath Viswanathan, Sandia National Laboratory, Albuquerque, NM 87185 Sandia National Laboratory, 2 Los Alamos National Laboratory, Los Alamos, NM 87545 Los Alamos, NM Los Alamos National Laboratory, 1 J. A. Philliber ; 1 ; M. Griffith : 1 ; Michael L. Steinzig 1 current investigation supports optimized properties with microstructural refinement. 8:50 AM Microstructure and Properties of LENS less Steel 94551 USA; USA Robinson 8:30 AM Fe-25Ni Samples Pro- Microstructure-Property Evaluations in duced with Directed Light Fabrication Hussen H. Harlow USA Many freeform fabrication efforts rely on the near-net shape production of parts with structural reliability throughout the component. As a result, significant effort is required to define and control the gain a better un- microstructural development during processing. To derstanding of direct laser fabrication techniques, the solidification behavior and resulting tensile properties have been studied in test bars of a model system, Fe-25Ni. By coupling systematic variations in process parameters with solidification modeling, microstructural investigations, and quasi-static mechanical testing, significant enhance- ments in the as-solidified properties are possible. For example, by doubling the laser traverse speed, the primary dendrite arm spacings decrease over 15%. Within these limits, the ultimate tensile strength increases 100 MPa (to 850 MPa) with a factor of two increase in ductility (to 6%). With cooling rates being on the order of 10 Sponsored by: Wednesday AMMarch 15, 2000 E Canal Room: Division, Organizers: Program Department, Austin, TX 78712- Mechanical Engineering Ames Iowa State University, 1063 USA; Iver Anderson, Sears, USA; James W. IA 50011-3020 Ames, Laboratory, NY Schenectedy, Lockheed Martin, KAPL Inc., D2, 114, Sandia National Laborato- 12301 USA; John E. Smugeresky, USA; Dan ries, Department 8724, Livermore, CA 94551-0969 Materials J. Thoma, Los Alamos National Laboratory, USA; Los Alamos, NM 87545-0001 Science and Technology, Oak Oak Ridge National Laboratory, Srinath Viswanathan, The Ohio State Ridge, TN 37831-6083 USA; Rob Wagoner, Department of Materials Science and Engineer- University, ing, Columbus, OH 43210 USA Session Chair: Oak Ridge, TN 37831-6083 USA Laboratory, International Symposium on Global Symposium International Materials Processing Innovations in Structure-Property and Manufacturing: Solid Free Form Evaluations in Fabrication vector content of the system. The different dislocation structures dislocation The different the system. content of vector char- phase, of the Martensitic nucleation for potencies have differing unstable becomes the embryo at which driving force by the acterized are structures and embryo dislocation growth. The to with respect limit systems in the low-potency small 2D and quasi-3D explored for to small embryo size. corresponding

WEDNESDAY AM 131 Glenn S.Daehn ure; thelatterbasedonuseofasimple failurecriterion. ment inbothstraindistributions and predictedpunch-height-to-fail- the accuracyofsimulations. The comparisonsshowgoodagree- sional finiteelementprogram.Experiments wereperformedtoassess the OlsenCupTest, werecarried outusingSHEET-S,atwo-dimen- test. Axisymmetricsimulationsof standardformingtests,especially with twolubricantsweremeasuredusingthedrawbeadsimulator(DBS) 304, andArmcoTM18CrCb.Frictioncoefficientsforthesealloys stitutive equationsweremeasuredforthreealloys:Type 409,Type verification ofsimulationtechniquesandaccuracywasrequired.Con- for automotiveexhaustsystems.Inordertoimprovecurrentpractice, improve theformingofhigh-chromiumferriticstainlesssteelsheet Acollaborativeresearchprogramisunderwaytounderstandand 1179 USA Dept. ofMatls.Sci.&Eng.,2041CollegeRd.,Columbus,OH43210- Svcs., 705CurtisSt.,Middletown,OH45044-3999USA; ert J.Comstock Experience withAxisymetricSimulationUsingSheet-S 10:40 AM ratio. enhanced underpressurecycling,especiallyforthosewithhighaspect formity ofdensitydistributioninsidecompositecompactswasgreatly ate thedensitygradientaftercompaction.Itwasfoundthatuni- density distribution.X-rayComputedTomography wasusedtoevalu- and shapewereinvestigatedtofindtheeffectofcyclicpressureon sure atroomtemperature.Compositecompactsofvariedaspectratio Aluminum andAluminawereconsolidatedunderstaticcyclicpres- sity gradientscanalsobereduced.Inthisstudy, mixedpowdersof using pressurecycling.Somelimitedpriorstudiesalsosuggesttheden- creased greendensityandmechanicalpropertiescanbefabricated tion ofmixedmetalandceramicpowders.Greencompactswithin- has beenshowntoproducesuperplastic-likeeffectsintheconsolida- shrinkage anddistortiononsintering.Compactionundercyclicload Low compacteddensityandgradientsleadtocomponent powders intocompactsthatthencouldbesinteredtooptimizestrength. that couldthenbeusedinthefabricationofmonolithicorcomposite to developnet-shapestructuralpartsisthroughfabricatingdieshapes Onewaythatrapidfree-formfabricationtechniquesmightbeused 43210 USA University, Matls.Sci.andEng.,2041CollegeRd., Columbus,OH Metal MatrixCompositeCompacts The EffectofCyclicPressureontheDensityDistributionin 10:20 AM 10:10 AMBreak mental tothequalityoffinalwireproduct. kept below100Kanditwasfoundthatexcessivesuperheatdetri- suggest thattoretainamorphousstructure,meltsuperheatshouldbe streams willbepresented.Melttemperatureprobingduringthecasting streaming. Theoptimisedprocessparametersfornozzledesignupto5 It isshownthatcastratescouldbeincreasedmanyfoldsthroughmulti ture control,onthequalityandpropertiesofwirewasinvestigated. stream asisthecurrentpractise.Additionally, theeffects oftempera- nozzle designstoaccommodatemulti-streamingasopposesingle increasing thewirecastrateusingFe-Si-BalloyWe reportourworkon experimental worktoexploretheattemptsthatwehavemadeat need tooptimisetheprocessparameters.Here,wearereporting rate ofwirecasting,whichisrestrictedtoapproximately10m/sbythe impediment forcommercialisationbelievedtoberelatedtheslow casting processhasnotprogressedtocommercialscale.Themain and theexpectedsavingsincostenergyforproduction,wire behaviour havebeenproduced.Despitetheseinterestingproperties neering propertiessuchasultrahighstrengthanduniquemagnetic melt spinningprocess.Anumberofcompositionswithexcitingengi- developed andarenowwellestablishedusingspecialisedwaterbath Thedirectcastingofwiresub-millimetredimensionshavebeen UK versity ofSheffield,Dept.Eng.Matls.,MappinSt.,SheffieldS13JD 1 1 ; KaipingLi ; JohnJ.Lannutti 2 ; RobertH.Wagoner 1 ; RobertH.Wagoner : Yuehong Fu 2 ; 1 ; GuangbinJiang 1 Armco Inc.,Tech. 1 ; 2 Armco Inc., 1 Ohio State : Rob- 1 ; ambiguous. bend testresultstoobtaincorrespondinguniaxialstress-straincurvesis sion/compression testsareidentical.However,interpretationofthe Within thescatterofexperiments,reversebendtestandten- The strainrangeobtainableinthebendexperimentissmall,+/-2%. versal, whiletwoanisotropichardeningmodelreproducethedatawell. results showsthatisotropichardeningmodelsfitpoorlynearthere- the reversebendtestwassimulated.Comparisonwith ing lawswereimplementedintoABAQUS,afiniteelementcode,and order toverifymaterialsmodelsgeneratedfromthetest,harden- procedures tomeasurehardeninglawsfollowingabruptreversals.In structed tostabilizein-planecompression,andusedwithcorrection used. Auniaxialtension-compressiondevicewasdesignedandcon- this reason,indirecttests,suchasbendingorin-planeshearhavebeen the sheetplaneisdifficultbecausebucklingoccursincompression.For DirectmeasurementoftheBauschingerEffectforsheetmetalsin 43210-1179 USA sity, Dept.ofMatls.Sci.andEng.,2041CollegeRd.,Columbus,OH Processing Plant,Rsch.Ctr., Ekaterinburg 620014Russia Alexander V. Yermakov, Ekaterinburg Non-FerrousMetals Co. KG,Heraeusstrasse12-14,HanauD-63450Germany; Session Chairs: March 15,2000 Wednesday AM 62001 Russia USA; PeterPanfilov, UralStateUniversity, Ekatrinburg Japan; R.D.Lanam,Engelhard-CLAL,Careret,NJ07008 National ResearchInstituteforMetals,Tsukuba, Ibaraki305 Laboratory, OakRidge,TN37831-6083USA;H.Harada, Program Organizers: Metals Committee Sponsored by: Processing, Refining,andChemistry International SymposiumonIridium: Geng Measurement oftheBauschingerEffectinMetalSheets 11:00 AM vary fromahundred micronsuptoseveralmillimeters. Thetechnol- efficient metaluse,andpurification of theiridium.Wall thicknesscan ites. Theadvantagesoftheprocess includeseamlessconstruction, facturing near-netshapesofiridium, iridiumalloysorcompos- Electroformingofiridiumisa highly specializedprocessformanu- 07008 USA A. Etenko Electroforming ofNear-NetShapes inIridium 8:50 AM is anomalousforFCCmetals. ties associatedwiththemechanismofbrittlefractureiridium,which this stagethatprocessingengineersencounteredconsiderabledifficul- duced mainlybythemethodofplasticdeformation.However,itis at less than0.01gramsfordisksandsamples.Iridiumarticlesarepro- dium productsvariesbetweentenkilogramsormoreforcruciblesand range ofiridiumproductsiscontinuouslyextended.Themass iri- ucts arefindinganeverincreasinguseinmoderntechnology. The Thankstotheiruniqueproperties,iridiumandiridium-alloyprod- Ekaterinburg 620014Russia 1 Ermakov Fundamentals ofIridiumPlasticalTreatment Technology 8:30 AM Ekaterinburg Non-Ferrous MetalsProcessingPlant,LeninAve. 8, 1 ; Vijay Balakrishnan 1 1 ; A.V. Sedavnykh ; V. Sikin Structural MaterialsDivision,Refractory David F. Lupton,W.C. HeraeusGmbH& 1 ; 1 Location: OprylandConventionCenter Room: JacksonA/B Engelhard-CLAL, 700BlairRd., Carteret, NJ Evan K.Ohriner, OakRidgeNational 1 ; Robert H.Wagoner 1 ; N.I.Timofeev 1 ; : 1 ; V. A.Dmitriev 1 Ohio StateUniver- A. Shchetkovskiy : : Lumin A. V. 1 1 ; ;

WEDNESDAY AM 132 . ; 4 6 1 IrF 2 V. N . -3HF 3 : ]F 6 O 2 COCHalCO- 3 ; V. N. Mitkin ; V. 1 min. The processes 2 Hal = Cl, Br, I; R ‘ =

C. The specific rate of ions there are always ° 2- ] in solutions under «Ox- 6 3- ] 6 Institute of Inorganic Chem. of Inorganic Institute 1 (1) and Ir (CH 3 . The product of Ir interaction ; g-atom/cm 3 1 (K, Rb, Cs) have been synthe- -7 6 (p = 1 atm) are studied with an ; L. M. Levchenko 3 1 has been studied. It is proved that has been studied. IrF in an inert and oxidative or reductive 4 and [IrF 3 3 C or the treatment by molten KBrF C or the treatment 2- ) ° 3 ] 6 , where «n» = 0,1,2; Institute of Inorganic Chemistry, Sbras, 3 Institute of Inorganic Chemistry, (2) and ClF 1 instead the iridium (III) fluorochloro-com- V. N. Mitkin N. V. is 6.2 x 10 2 n 3 , C (CH 3) n-3 ; 3 : ] and KBrF 1 n 3 V. G. Isakova V. C. Apparent activation energies of the processes C. Apparent activation ° : O) C are determined by presence in oxidant of addi- C are determined by presence , CF 2 ° 3 ions as contrasted to [IrF C and 14.1 kcal/mol at 38-65 C and 14.1 kcal/mol at 3- , BrF (H ° ] 3 6 6-n . It has been also determined that the most convenient . It has been also determined 6 . The features of Ir dissolution kinetics in a liquid bromine . The features of Ir dissolution C always results in formation of Ir(V) hexafluorocom- in formation of C always results - , ClF COCHCOCH ° ] is hexafluoroiridate(V) of difluorobromonuim (III)- is hexafluoroiridate(V) 2 3 6 3 ; R “ = CH 3 ; V. G. Isakova ; V. [IrF (CH 1 + ] CF 3-n

2 ) , 3 3 F and spectrophotometry have been applied to the study of the F and spectrophotometry have been applied Institute of Inorganic Chemistry, Sbras, 3 Lavrentjeva Ave., Chemistry, Institute of Inorganic CH are 18.9 at 25-38 Ir dissolution in pure BrF of thermography and application of the specially designed variants There are determined an optimal conditions of thermogravimetry. Novel less-known hexafluoroiridate (VI and V) synthesis. hexafluorocomplexes of Ir(III)-M has been separated in a solid state for the first time. These results have been applied to preparative chemistry and to the development of original direct high-yield synthesis of the various coordination compounds of iridium using hexafluoroiridate (III and IV) starting materials. AM 11:20 The Thermoanalytical Study of Ir(III)-Beta-Diketonate’s Atmospheres Behaviour in Inert, Oxygen and Hydrogen Mitkin CH gaseous atmosphere. The thermal decomposition processes of (1) and (2) have been studied by means of Hungarian thermoanalyser Q-1000 in an atmosphere of He, H2, and O2. The resulting and intermediate solid products yielded after thermal «Ox-Red»-transformations at the controlled gaseous media (at atmospheric pressure) and at the selected temperatures have been studied by physical-chemical methods. It has been established that the series of compounds (1) represent a higher thermal stability in hydrogen atmosphere than for thermal decompo- tives of bromium and also availability of the ionogenic forms. Thus, tives of bromium and the dissolution of iridium whereas the do- the Lewis acids accelerate the process. The bromium also slows nors of fluoride-ion decelerate the process at 25-38 1 Novosibirsk 630090 Russia (IV) hexachlorocomplexes The processes of iridium metal and iridium oxidation by a gaseous F complexes M sized under hetero-phase reduction from appropriate 19 transformations of the ions [IrF plexes. The novel iridium (III) crystalline complex [Ir(H Novosibirsk 630090 Russia Lavrentjeva Ave., There are investigated the thermal behaviour of the volatile beta- diketonates of Ir(III) Ir(R’COCHCOR”) 10:40 AM 10:40 Possibilities Its Application and Iridium Metal of Fluorination Sec- for and Recovery Analysis Synthesis, in the Technology Raw Materials ondary 630090 Russia Novosibirsk Lavrentjeva Ave., SB RAS, 3, and its fluorination of iridium regularity in oxidizing The basic or molten by various gaseous, liquid alkali metal fluorides mixes with reactants-F at 270-350 gas-phase processing at 350-450 plexes-MIrF sense for transfer of the compact metal fluoroxidant in its common is a liquid BrF into the oxidised state with BrF [BrF trifluoride at 25-65 were evaluated for analytical pur- of iridium oxidizing fluorination trifluoride or potas- poses. It is proved that the application of bromine of chemical sample sium tetrafluorobromate can be a unified method of secondary iri- preparation. The methods of oxidising fluorination and are suitable to dium raw materials permit 98-99% metal recovery practical use. AM 11:00 of Iridium (III- Synthesis and Physical-Chemical Investigation V) Fluorocomplexes IR-spec- potentiometry, All iridium fluorides are characterized by the diffraction and elemental analysis. The methods NMR X-ray troscopy, been established that in Red» and ligand-exchange processes. It has more labile [IrF of mixed-ligand taken place the aquatation process with the formation complexes [IrF ; 1 S. : A. V. ; 1 ; L. D. Gorbatova 1 Murdoch University, AJ Murdoch University, : N. I. Timofeev 1 ; Oak Ridge National Labora- Oak Ridge 1 1 ; 1 Engelhard-CLAL, 700 Blair Rd., 1 ; 1 M. J. Nicol ; G. F. Kuzmenko ; G. F. 1 : ; J. F. King ; J. F. 1 J. D. Ragaini : ; V. I. Bogdanov ; V. 1 ; Evan K. Ohriner 1 Ekaterinburg Non-Ferrous Metals Processing Plant, The Head of Rsch. Ekaterinburg Non-Ferrous Metals Processing Plant, Parker CRC, South St., Murdoch, Western Australia 6150 Australia Parker CRC, South St., Murdoch, Western The separation of iridium from rhodium in chloride solutions during the refining of platinum metal concentrates is one of the most difficult steps and is generally carried out using either solvent extraction or ion exchange. In both cases, the separation process makes use of the fact that the hexachloroiridium (IV) ion is less strongly hydrated and more polarizable than the hexa- or penta-chlororhodium (III) species. This results in either selective extraction into solvating solvents or selective adsorption onto anion exchange resins of the iridium. It is obvious that control of the speciation is crucial in ensuring efficient separation. This paper will describe the use of relatively simple macro- and micro-electrode cyclic voltammetric techniques for the rapid identification of the iridium species present in solutions obtained during various stages of the conditioning process prior to separation by ion exchange. Yermakov Ctr., Lenin Ave. 8, Ekaterinburg 620014 Russia 8, Ekaterinburg Lenin Ave. Ctr., of iridium from pri- The new universal technology for extraction has been elaborated. mary concentrates and refining secondary iridium of iridium in ´poorª Hydrometallurgical means allow increasing contents secondary iridium are concentrates up to 98%. After that primary and included itself oxidation directed to the pyrometallurgical processing and electron-beam melting of scrap in periclase magnesia crucible massive single crystals melting. The final stage of refining is growing metal with purity by means of electron-beam zone melting. Resulted of 99.95% is high pure plastic iridium, which could be processed without considerable troubles. 10:10 AM Break 10:20 AM The Monitoring of the Speciation of Iridium in the Separation Rhodium of Iridium from 1 Carteret, NJ 07008 USA temperature perfor- The superior corrosion resistance and high for the severe condi- mance of iridium make it the material of choice cost of the metal. Refin- tions of many industrial processes despite the commercial demands by ers of precious metals strive to satisfy these purified iridium of treating primary ores and recycled scrap to produce The treatments can be fairly straightforward or acceptable quality. the material fed into the quite complex, depending on the nature of described. Some of these processes are refinery. 9:50 AM Recovery and High Refinement of Iridium A. David USA Oak Ridge, TN 37831 Box 2008, P.O. Div., Mets. and Cer. tory, used as post- thorium are currently W alloys doped with Ir-0.3% for radioactive fuel in thermoelectric impact containment material stable electrical power for a variety of outer generators that provide and weldability of a series of alloys was planetary missions. Welding laser welding processes. Some of these alloys investigated using arc and of these during welding. Weldability are prone to severe hot-cracking using Sigmajig weldability test. Hot-cracking alloys was characterized extent by the fusion zone microstructure and is influenced to a great to content and welding atmosphere were found composition. Thorium be cracking behavior in these alloys can be very critical. The weld the fusion zone microstructure. Fusion zone controlled by modifying to be controlled by welding process, process microstructure was found pool shape. The paper will discuss in detail parameters, and the weld between the process-microstructure and the inter-relationship weldability of iridium alloys. 9:30 AM Iridium Refining ogy makes it possible to consider the uses of iridium for new products, for new of iridium the uses to consider it possible ogy makes rea- or financial technological because of considered not previously, will be product applications products and of examples Various sons. discussed. 9:10 AM Iridium Alloys of Thorium-Doped Weldability and Welding

WEDNESDAY AM 133 two elementsexisted. dium. Untilrecently, nosatisfactorymethodfortheseparationof rhodium andiridiumpresentsthemostdifficulttaskinrefining iri- iridium fromtheaforementionedstartingmaterial.Separation of and Rh.Severalhydrometallurgicalschemesareknowntoseparate backs, primarilyinadequateselectiveextractionofsuchmetalsas Pt drometallurgical. However,thistechnologicalschemehassomedraw- pyrometallurgical processing.Theresultingsublimatesunderwenthy- and silicon.Itwasacommonpracticetotransferthesematerials and thesamepercentageofbaseelements,mainlycopper,lead,iron, chloroiridate contains20to40%iridium,up10%ofotherplatinoids, is formedduringtherefiningofplacerplatinum.Ammonium Anintermediateproduct-technical-gradeammoniumchloroiridate- ing Plant,LeninAve. 8,Ekaterinburg 620014Russia Gorbatova Materials ofIridium Metals duringProcessingofHeavilyContaminatedStarting On thePossibilityofElectrochemicalSeparationPrecious 12:00 PM year. industrial electrolysis,andthedemandforthisuseisincreasingyearby mental impact.Thus,theiridiumoxideplaysanimportantrolein mendous contributiontoproductquality, energysavings,andenviron- electro-galvanizing, electro-tinning,metalwinnings,etc.,withtre- hours atpresent.ApplicationwasalsomadetoCu-foilproduction, 1000 hoursinstandardsulfuricacidelectrolysistolongerthan10,000 with improvementsindurability. Theservicelifehasincreasedfrom num basedorleadalloyanodes.Theapplicationisincreasingtogether Japan atfirstandprovedtobefarsuperiortheconventionalplati- ized astheoxygenevolutionanode.Thatwassuccessfullyappliedin commercialization inchlor-alkali,iridiumoxideDSAwascommercial- dium demandwillbecomeatleast600kg/year. Severalyearsafterthe NaOH. Withfurtherconversiontothemembraneprocessworldiri- C12 wasattainedwithlowerpowerconsumptionof2,000kWh/ton- and iridiumoxideswasapplied.Morethan10yearsoflifelowO1/ selectivity becamerequiredtoDSA,whereacombinationofruthenium cess conversiontomembranesystem,higherdurabilityandreaction ruthenium oxidewasusedwithtitaniumoxide.Accordingtothepro- tion ofitwastothemercuryprocesschlor-alkalielectrolysis,where are usedasoxidecoatingontitanium.Thefirstcommercialapplica- dium becamepopularintheelectrochemicalfieldasDSA,wherethey SincethegreatinventionofDr. Beer, in1965,rutheniumandiri- Minamiohtsuka Bldg.,37-52,Toshima, Tokyo 170-0005Japan trolysis Iridium Oxide-ExcellentElectrodeMaterialtoIndustrialElec- 11:40 AM halogenides. acetylacetonates (2)decomposedwiththeformationofbinaryiridium mally decomposedwiththeselectionofmetal,buthalogenated proved thatacetylacetonatesofIr(III)-Ir(R’COCHCOR”)3arether- compared toappropriateacetylacetonatesofiridium(III).Ithasbeen iridium (III)halogenatedacetylacetonateshaveincreasedvolatilityas ity of(1)and(2)hasbeenconducted.Itproved,that(2)-an pounds. Thecomparativeanalysisofthevolatilityandthermalstabil- oxygen atmosphereareessentiallyreducedforthisseriesofcom- sition inHe.Atthesametimetemperaturesoftransformations : T. Shimamune 1 ; K.P. Konik : 1 1 ; ; A. V. Yermakov 1 1 Furuyametals CompanyLimited,MSB-21, Ekaterinburg Non-FerrousMetalsProcess- 1 ; V. I.Bogdanov 1 ; L.D. powders withhighyieldslessthan20micronsusingAr,N effective methodsofproducingrapidlysolidifiedfinemetalandalloy discrete jetatomizationmethod,hasprovedtobeoneofthemost trolled size.Highpressuregasatomization(HPGA),aclose-coupled, ability offine(dia.<45micron)powdersorcoarsercon- Manyapplicationsforparticulatematerialsdemandeithertheavail- 50265 USA 1 Control Gas AtomizationProcessingwithHighEfficiencyandSize 8:30 AMInvited 01810 USA USA; StephenJ.Mashl,BodycoteIMT, Andover, MA Standards &Technology, Gaithersburg, MD20899-8556 Session Chairs: March 15,2000 Wednesday AM NIST, Gaithersburg, MD20899-8556USA Gaithersburg, MD20899-8556 USA;StephenD.Ridder, Washington, DC20375-5343USA;FrankBiancaniello,NIST, Laboratory, MaterialsScienceandTechnology Division, Program Organizers: Division, PowderMetallurgyCommittee Sponsored by: tals andPractice:GasAtomization Liquid MetalAtomization:Fundamen- compared todata obtainedfromannularconverging andconverging- the supersonicjet behavior. Thediscrete jetnozzledataarethen ferent nozzlediametersareincluded tostudyhownozzlescaleaffects overall diametersarereportedfor severalnozzlepressureratios.Dif- acteristics oftwodiscrete-jetclose-coupled nozzleshavingdifferent other. Inthisstudy, thesupersoniclengthand dynamic pressurechar- potential atomizingcapabilityof one close-couplednozzleversusan- gas dynamiccharacteristicsmaybe usedasbenchmarkstocomparethe omization, yieldingasmalleraverageparticlesize.Assuch,thesetwo supersonic lengthswilltendtoproducemorecompletesecondary at- distances fromthenozzletip.Higherdynamicpressuresandlonger in whichmoltendropletsaredisintegratedintofineparticlesoverlong sonic length,stronglyaffectthecriticalsecondaryatomizationstage, times velocitysquared)developedinthisgasjet,aswellitssuper- supersonic gasjet.Themagnitudeofthedynamicpressure(density to atomizemoltenmetalintofinepowdergenerallyproducealong Well-designed close-couplednozzlesoperatingathigh gaspressures Stop 8556,Gaithersburg,MD20899-8556USA Stephen D.Ridder Nozzles UsedtoProduce FineMetalPowders Characteristics ofDiscrete-JetandAnnularClose-Coupled Comparison oftheSupersonicLengthandDynamicPressure 9:00 AMInvited Iowa StateUniversityResearchFoundation. Advanced Technology underDOCcontractno. ITA81-02, andthe by USDOE-BESundercontractno.W-7405-Eng-82,theCenterfor ciency willbedescribed.Differentaspectsofthisworkweresupported control. Examplesofpowdersizecontrolandcomparisonseffi- over anextremelywidepressurerange,advantageousforpowdersize has beentheabilitytooperateinanearlyconstantaspirationmode of thegasdynamicsinatomizationzone.Anunexpectedbenefit jets inanatomizationnozzlerequireddevelopmentofaphysicalmodel increase atomizationefficiency anduniformity. Efficient useofC-D nozzle designsthathavehightotalkineticenergywasconductedto Development ofHPGAjetswithconvergent-divergent(C-D)rocket Research, Pittsburgh, PA 15205USA; Ames Laboratory, 126MetalsDev., Ames,IA50011 USA; : Iver E.Anderson Materials ProcessingandManufacturing 1 ; FrankS.Biancaniello Stephen D.Ridder, NationalInstitutesof Location: OprylandConventionCenter Room: BayouB Khershed P. Cooper, NavalResearch 1 ; R.L.Terpstra 3 Delevan, West DesMoines,IA 1 ; 1 1 NIST, 100BureauDr., ; JasonTing : Steven P. Mates 2 , orHegas. 2 ; C.Yu 2 Crucible 3 1 ; ;

WEDNESDAY AM 134 ; : 1 Frank S. : ; Rick E. Ricker 1 ; Stephen D. Ridder 1 NIST, 100 Bureau Dr., Stop 8556, Gaithersburg, MD Gaithersburg, Stop 8556, 100 Bureau Dr., NIST, 1 NANOVAL GmbH & Company KG, Holzhauser Str. GmbH & NANOVAL 1 ; 1 ; 1 ; R. D. Jiggetts 1 Biancaniello 157-159, Berlin D-13509 Germany ways of atomizing as a The Nanoval process differs from all other inner pressure, given by melt stream bursts open by itself when its of a steadily accel- surface tension forces, surpasses the outer pressure effect is observed in erated gas flow in Laval nozzle. This Nanoval is fine and ultra- laminar flow of both, melt and gas. Its consequence narrower than usual. fine spherical powder at particle size distributions using a hydraulic closure A new autoclave system omits plug rods in production. Atom- unit, which enables continuous or semi-continuous and ultra-fine powder izing results are shown for the production of fine of various metals. frequency distribution curves also indicated bi-modal size distribution bi-modal also indicated curves distribution frequency distribu- size and particle investigation SEM powders. Detailed in the The the powders. in size distribution narrow indicated tion analysis modifications nozzle design pressure and gas of the atomising effect in the Mg tight size distribution both explain the observed were used to produced. and Al powders AM Invited 11:00 of Gas and Properties into the Processing An Investigation Stainless Steels High Nitrogen Austenitic Atomized Mark R. Stoudt 20899-8556 USA stainless steels are known to possess improved Nitrogen containing production of alloys with these superior properties. The consistent by rapid solidification processing which elimi- properties is enhanced that inhibits consistently obtaining out- nates the macrosegregation evalu- these alloys through ingot processing. To standing properties in of gas atomization enables the production ate the extent to which with improved properties, a series of alloys was nitrogen bearing alloys model to guide alloy and process design, produced using a predictive of corrosion and stress corrosion properties and then, the mechanical, The model used to predict nitrogen solu- these alloys were evaluated. quench rate sensitivity. bility and alloy properties also led to a reduced powders or subsequently This property in turn allows for the atomized These applica- extruded wire to be used for thermal spray applications. of the mechanical and tions will be discussed along with the results corrosion properties. AM Invited 11:25 Special Products for Atomizing: A Special Process NANOVAL Martin Stobik ; 2 Gazi 1 ; 1 ; A. Sepúlveda 2 Universidad De Chile, 2 Sedat Özbilen : HJE Company Inc., 151-155 Maple HJE Company 1 ; ; Rodrigo H. Palma 1 1 Joseph T. Strauss Joseph T. Leonel L. Núñez : : Universidad Central de Chile, Facultad de Ciencias Físicas y Universidad Central de Chile, Facultad University, Metallu. Edu. Dept., Teknikokullar, Ankara 06500 Tur- Metallu. Edu. Dept., Teknikokullar, University, key Mg powders under low pressure Ar gas and Al powders under Ar gas with nozzle design modifications were produced on a pilot plant gas by SEM Mg and Al powders produced were characterised atomiser. investigation and by laser particle size analysis. It was observed that Their the powders produced obeyed log-normal size distribution law. Dept. De Ingeniería Mecanica, Casilla, Santiago 2777 Chile Dept. De Ingeniería Mecanica, Casilla, Santiago liquid metal atomizers It is recognized that the performance of gas liquid gas flow, is a function of the following variables: atomization and size distribution of powders. However, productivity metal flow, atomizers show that the most of the studies of confined and gravity interaction between gas aerodynamic pressure field, developed by the of them. On the other jets, controls the behavior and performance about behavior and per- hand beyond the efforts to make predictions equations to make design formance of atomizers, there are no reliable configured with indepen- calculations. It is well known that atomizers a condition suitable to dent or annular nozzles develop choked flow, estimate equations. To evaluate the gas flow with compressible flow equation has been the particle mass median diameter, the Lubanska that this experi- used; however many researchers have demonstrated particularly for con- mental correlation does not give good results, comprehension of confined atomizers. It seems that a key for the the understanding of the fined and gravity atomizers’ performance is of the great quantity aerodynamic pressure field. In this area, in spite atomizer types, no ef- of published experimental results for several in order to pro- forts have been done to systematize the information field formation. In pose theoretical models that explain the pressure metal-atomizer are devel- this work, the general equations of gas/liquid oped on the basis of fundamental principles and experimental results. The atomization gas flow and the liquid metal flow are evaluated from fluid dynamics principles. It is worth noting that the liquid metal flow equation, an important equation to estimate the atomized powder size, is a function of the aerodynamic pressure field. A procedure to analyze reported experimental pressure fields is developed. The purpose is to contribute to the understanding of the principal controlling variables and to the theoretical prediction of pressure fields. Moreover, a mul- tivariate analysis of powder-size experimental data is conducted to equation. In this case, the objective propose corrections to Lubanska’s is the development of an equation to evaluate the particle mass median diameter for several atomization regimes. 10:20 AM Break 10:35 AM The Possibility of Narrow Size Distribution in Gas Atomised Powders by Nozzle Design Modifications 1 Civiles, Sede Parque Matemáticas, Escuela de Ingeniería Civil en Obras Almagro Sur, Santa Isabel, Santiago 1186 Chile; St., Glens Falls, NY 12801-3729 USA NY 12801-3729 St., Glens Falls, sys- close-coupled atomization of a small-scale The development with goals of increasing the reliability, tem has evolved incrementally and repeat- and performance. Reliability predictability, repeatability, to be primarily functions of component design ability have been found Insight into performance and predictabil- and operational parameters. of flow bench testing and correlation ity were gained by a combination gas to metal flow rate ratio, gas momentum, of particle size data with review prior studies investigating the This paper will and gas energy. properties and operational parameters on par- effects of melt and gas of gas-only aspiration tests and water bench ticle size. The merit Salient design details are reported. testing will be discussed. 9:55 AM Invited Liquid Metal Atomizer Performance and Understanding the Behavior diverging close-coupled nozzles to gauge their relative performance. their relative to gauge nozzles close-coupled diverging per- to round, are compared nozzle data the close-coupled Finally, longest and are the narrowest jets, which supersonic expanded fectly rate. and gas flow ratio given pressure jets at any possible Invited 9:30 AM Empirical Atomization: An in Close-Coupled Improvements Approach

WEDNESDAY AM 135 USA Company, Matls.Sci.Dept.,ScientificRsch. Lab., Dearborn,MI48121 Eng., 2300HaywardSt.,AnnArbor, MI48109USA; John E.Allison havior ofDie-CastAM50Alloy The EffectofCalciumonCreep andBolt-LoadRetentionBe- 9:20 AM ment, duetotheformationoffineprecipitatesatlowtemperatures. over, itsmechanicalpropertiesareimprovedsignificantlybyT6treat- temperature was6%,whichishigherthanthatofAZ91alloy. More- times ashighthatofAZ91alloy. Thebreakingelongationatroom 150 same condition.Theultimatetensilestrengthwasover200MPa at developed inthisstudywas1/100ofthatAZ91alloyunder the such asT6treatedQE22alloy. Theminimumcreeprateofthealloy MPa wasnearlyequaltothatofconventionalheatresistantalloys property ofahigh-pressuredie-castingthealloyat150 compartment. Thisnewalloyshowshighcreepresistance.The tance wasdevelopedforutilizationinautomotivepartstheengine Mg-2%Zn-0.8%Ca-2%Mm -0.5%Zralloywithexcellentheatresis- Bytheadditionofcalcium,mishmetalandzirconium,alowcost Nagakute, Aichi480-1192Japan Lightwt. &Environ.Matls.Lab.,41-1Aza-Yokomichi, Oasa-Nagakute, Yoji Awano Strengthened byCaAddition Development ofHighCreep-ResistantMagnesiumAlloy 8:55 AM compression issignificantlyhigherthanthatintension. n~5 (stressrange20-60MPa).Interestingly, the creepstrengthin range of0.7Tm,thestressdependencesteadystatecreeprate, lier studiesofmagnesiumalloyscreepbehaviorattemperaturesinthe the tensileandcompressivecreepbehaviorofAM60.Similartoear- testing hasbeenperformedinatensilemode.Inthisstudywecompare the criticalloadsarecompressive.Inspiteofthisfact,mostcreep applications underconsideration,suchasboltedhousingsandcovers, AM60, theformerisstrongerbutlattertougher. Formany studied. Ofthetwomostcommonlyuseddie-castingalloys,AZ91and resistance, thecreepbehaviorofexistingcommercialalloysisbeing the bestcoursefordevelopingdie-castalloyswithimprovedcreep application istheirpoorcreepresistance.Inanefforttodetermine the limitationsofmagnesiumalloysthathashinderedmorewidespread effort toimproveefficiencythroughvehiclemassreduction.Oneof motive industry, inincreasedusageofmagnesiumbased alloys inan Therehasrecentlybeenrenewedinterest,onthepartofauto- Ridge NationalLaboratory, OakRidge,TN37831USA sium Alloy, AM60B Tensile andCompressiveCreep BehaviorofDie-CastMagne- 8:30 AM Hydro LightMetals,Livonia,MI48152USA Session Chair: March 15,2000 Wednesday AM Association, McLean,VA 22101USA 60439-4815 USA;ByronB.Clow, InternationalMagnesium John N.Hryn,Argonne National Laboratory, Argonne, IL Corporation ofAmerica,SaltLakeCity, UT84116 USA; Program Organizers: Committee, InternationalMagnesiumAssociation Sponsored by: Properties andHeatTreating Effects Magnesium Technology 2000:Creep ° . ThisvalueisnearlyequaltothatofT6treatedQE22and1.2 1 ; Yoshiki Seno 2 ; Light MetalsDivision,Reactive Darryl L.Albright,HydroMagnesium, 1 University ofMichigan,Dept. Matls.Sci.and : S. R.Agnew Location: OprylandConventionCenter Room: BayouD Howard I.Kaplan,Magnesium 1 ; 1 Toyota CentralR&DLaboratoryInc., : : 1 ; K.C.Liu Keun Yong Sohn Toshio Horie 1 ; S.Viswanathan 1 ; HiroakiIwahori 1 ; J.Wayne Jones 2 Ford Motor ° under64 1 ; 1 Oak 1 1 ; ; sium Alloys Preparation andSolidificationFeaturesofAsSeriesMagne- 10:20 AM 10:10 AMBreak and therare-earthcontainingAE42alloy. falls intherangeofhighpuritymagnesiumalloysAZ91DandAM60B 0.11- 0.23mg/cm2/day, asmeasuredthroughsalt-spraycorrosiontest, taining magnesiumalloys.Corrosionresistanceofthediecastalloysat and diecaststateareequivalenttothemoreexpensiverare-earthcon- tensile strengthofthealloyat150 ture increepresistance.Thetensileyieldstrengthandtheultimate the alloybeforeandaftercreeploadingshowsroleofmicrostruc- compound intheas-caststructure.Microstructuralinvestigationof tance ofthealloyisduetoexistenceanAl2Caintermetallic that hasgoodcreep-resistanceat150 sistance. ThisstudyisonthedevelopmentofaMg-Al-Caalloysystem Blvd., Pointe-Claire,QuébecH9R1G5Canada; Pekguleryuz components forelevated-temperature(150 effective alloysthatcanmeettheperformancerequirementsofthese as transmissionandenginepartsrequiresthedevelopmentofcost- structural components.Itsuseincriticalcomponentssuch Theautomotiveuseofmagnesiumiscurrentlyrestrictedtonon- gies, 357RueFranquet,Ste-Foy, QuébecG1P4N7Canada Creep ResistantMg-Al-CaCastingAlloys 9:45 AM will bedescribed. of theAMCalloys.TEMinvestigationas-castandcreptspecimens AE42. Similarly, theAMC5007alloyshowedlowestcreepstrain showed thebestBLRproperty, withahigherBLRresistancethan relaxation andcreepresistance;AM50alloywith0.75%Ca(AMC5007) from 14to28kN.Highercalciumcontentalloysshowedbetterstress MPa. BLRtestshavebeencarriedoutfrom125to175 carried outatatemperatureof150 0.50, 0.75%)inbaseAM50alloyweredie-cast.Creeptestshavebeen be investigated.Fouralloyswithdifferentcalciumcontent(0,0.25, tion (BLR)behavioratvarioustemperaturesandstresses/preloadswill ings. Inthisstudy, theeffect ofcalciumoncreepandbolt-loadreten- greatly improvestheelevatedcreepresistanceofmagnesiumdie-cast- under investigation.Ithasbeenshownthatsmalladditionsofcalcium cost approachesforcreepresistantmagnesiumalloysarecurrently creep resistance,concernsaboutalloycostlimitwidespreaduse.Lower magnesium alloyssuchasAE42havebeenshowntoacceptable plications requiregoodcreepresistanceatelevatedtemperatures.While Magnesiumdie-castingalloysforautomotivetransmissioncaseap- Matls. Eng.,CRC forAlloyandSolid.Tech., Brisbane, QLD4072 R. Griffiths Sand CastAZ91Alloy On theRelationbetweenHardness andYieldStrengthina 10:45 AM closed. cussed andthefactorsaffecting microstructurefeaturesweredis- transformations occurringthroughthesolidificationprocessisdis- are presentintheAS21andAS41ingots.Thesequenceofphase evident fromtheresultsofpresentinvestigationthatadditionalphases the solidificationprocessofAS21andAS41alloys.However,it is resistance. ItwasbelievedthatonlyMg alloys. SiliconisaddedtoMg-Alalloysinorderenhancethecreep dure byMnandotherelements,particularlySiinAS21AS41 sium isveryimportantforestablishingtheefficientalloyingproce- which influencethemutualsolubilityofMnandFeinmoltenmagne- manganese toremoveiron.Hence,theunderstandingoffactors alloys inserviceconditions.Magnesiumareusuallyalloyedwith of AS21andAS41alloyscanaffecttheperformancethese dure andphaseconstituentsthatareprecipitatedduringsolidification investigation wastoobtaininformationregardingpreparationproce- tions thatrequireadequatecreepresistance.Theaimofthepresent ASmagnesiumalloyseriesareusedforhightemperatureapplica- sium Limited,P.O. Box75, Beer-Sheva 84100Israel 1 2 : ; JeanRenaud ; B. Bronfin 1 University ofQueensland,Dept. of Ming.,Min.and : ClareL.Bancroft 1 ; M.Katsir 2 ; 1 Noranda Technology Center, 240Hymus ° ° C andinitialstressesfrom30to90 C bothinthepermanent-moldcast 1 ; E.Aghion ° 2 C. Theincreasedcreepresis- Si particlesareformedthrough 1 ° ; C) strengthandcreepre- Carlos H.Cáceres 1 ; 2 Intermag Technolo- : 1 Dead SeaMagne- ° C andpreloads Mihriban O. 1 ; John

WEDNESDAY AM 136 ; ; 1 1 ; David Henry StJohn ; Arne Kristian Dahle 1 1 Mark Denis Nave Howard I. Kaplan, Magnesium Howard I. : ; Arne Kristian Dahle Room: Bayou C Convention Center Location: Opryland 1 The University of Queensland, Dept. of Ming., 1 eutectic exhibits a wide range of morphologies ; 1 12 Peter Pinfold, Fluor-Daniel, c/o Doe Run Peter Pinfold, Fluor-Daniel, Light Metals Division, Reactive Metals Division, Reactive Light Metals Al 17 Mark Denis Nave : University of Queensland, Dept. of Ming., Min., and Matls. Eng., University of Queensland, Dept. of Ming., David Henry StJohn Min. and Matls. Eng., CRC for Alloy and Solid. Tech., Brisbane, Min. and Matls. Eng., CRC for Alloy and Solid. Tech., Queensland 4072 Australia Previous experimental work has suggested that the addition of zinc to hypoeutectic magnesium-aluminium alloys promotes the formation of a divorced eutectic. However, the amount of zinc required to produce this effect has not been quantified and the mechanism by which it occurs has not been determined. This paper reports the results of a study of the effect of zinc on eutectic morphology in permanent mould cast hypoeutectic magnesium-aluminium alloys, including the commercial alloy AZ91. The results show that the strength of this effect varies with aluminium content and cooling rate. The addition of 1.6 wt% Zn to a Mg-9Al alloy cooled at approximately 80 K/s was sufficient to cause a fully divorced eutectic to form when a partially divorced eutectic formed in the binary alloy solidified at the same rate. An addition of 1.6 wt% Zn to a Mg-15Al alloy cooled at approximately 20 K/s was sufficient to cause a partially divorced eutectic to Magnesium Technology 2000: Technology Magnesium Solidification by: Sponsored Association International Magnesium Committee, Program Organizers: USA; UT 84116 City, of America, Salt Lake Corporation IL Argonne, Laboratory, National John N. Hryn, Argonne International Magnesium B. Clow, 60439-4815 USA; Byron 22101 USA VA Association, McLean, AM Wednesday March 15, 2000 Session Chair: Peru, La Oroya Peru 8:30 AM Al- Eutectic Growth Morphologies in Magnesium-Aluminium loys 1 Brisbane, Queensland 4072 Australia CRC for Alloy and Solid. Tech., The Mg-Mg conditions. An alloy depending on the alloy composition and cooling a lamellar morphol- of eutectic composition, Mg-33 wt% Al, exhibits at higher growth ogy at low growth rates and a fibrous morphology al- rates. However, in low aluminium content magnesium-aluminium magnesium alloys AZ91 loys such as the most common commercial described as either morphology, and AM60, the eutectic has a different reports the results of an completely or partially divorced. This paper and cooling rate on investigation into the effect of aluminium content mould cast magnesium- the morphology of the eutectic in permanent contents ranging aluminium alloys. Magnesium alloys with aluminium The effect of aluminium from 9 to 33 wt% were cast into steel moulds. regions in the differ- content was determined by comparing equivalent was determined by com- ent castings while the effect of cooling rate and the centre of each paring the microstructures obtained at the edge increased, the domi- casting. As the aluminium content of the alloys from fully divorced nant eutectic morphology changed progressively to lamellar. to fibrous and, finally, to partially divorced, to granular, change in the opposite Increasing the cooling rate produced a small higher aluminium con- direction with these transitions occurring at and cooling rate on tents. The influence of both aluminium content eutectic morphology results from the effect of these variables on dendrite morphology and the consequential size of the eutectic regions. 8:55 AM The Role of Zinc in the Eutectic Solidification of Magnesium- Aluminium-Zinc Alloys . ; ; n 1 1 Enrico ; Tim J. ; Tim 3 : C. In this ° University of 2 CSIRO, Manu. 2 ; Pasquale Cavaliere 1 the true plastic strain, the true plastic ε Amanda Lee Bowles C, even if a 4h treatment : ° University of Ancona, Dept. 1 ; ; Cameron J. Davidson 2 3 C on the mechanical properties of properties the mechanical C on ° C for times of up to 5,000 hours. ° ; Stefano Spigarelli 1 is the true stress and is the true stress σ ; Volodia Ezersky ; Volodia 2 ; P. D. D. Rodrigo D. ; P. 3 , where n ε C for times ranging 0.5h to 24h. SEM and Light Micro- ° ; Marcello Cabibbo CSIRO Manufacturing Science and Technology, P.O. Box P.O. and Technology, Science Manufacturing CSIRO 1 The University of Queensland, Co-op. Rsch. Ctr. for Alloy Co-op. Rsch. Ctr. The University of Queensland, 2 1 = K σ ; 2 C produced an equiaxed structure of alpha grains; in particular ° CSIRO, Manu. Sci. and Tech., P.O. Box 883, Kenmore, Queensland Box 883, Kenmore, P.O. Tech., CSIRO, Manu. Sci. and after 24h aluminium was completely in solid solution, its distribution being substantially homogeneous. The distribution of Al and Zn in the microstructure was investigated by means of X-rays diffraction. The effect of solution treatment-time was investigated by means of tensile tests; the poor ductility typical of the thixoformed alloy was substantially improved by increasing the heat treatment duration over 2h. Additional studies were carried out in order to assess the creep response of the solution-treated material. produced a more homogeneous structure. Solution heat treatment at 415 of Mech., Via Brecce Bianche, Ancona 60131 Italy; of Mech., Via Box 653, Beer-Sheva, Negev Dept. Matls. Sci. and Eng., P.O. Negev, 84105 Israel and mechanical prop- The present study is focused on the structural The microstructure erties of an AZ91 Mg-alloy after thixoforming. by quasi-eutectic consisted of large alpha-phase globules separated areas are devel- (alpha+beta). Observations showed that the alpha-Mg oped into individual grains, while the beta-phase (Mg17Al12) particles are present only in the eutectic area. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) revealed small Mg-rich particles inside the eutectic (divorced eutectic). The heat- treatment response of the alloy was investigated after a solution treatment at 415 scope (LM) showed that the original microstructure produced by thixoforming was almost completely transformed in a conventional structure of equiaxed grains after 2h at 415 Bastow alloys AZ91D and research, high-pressure die-castings of the Mg-Al AM60B have been aged at 120 on the tensile proper- Results are reported for the effect of this aging yield stress of up to 30 ties and on the microstructure. Increases in the increase for 2 mm MPa were noted for 5 mm thick castings but ductility of all castings thick castings was far less, at about 6 MPa. The of the microstructure was reduced by more than half. Observations microscopy and by have been carried out by optical and electron shown that precipita- nuclear magnetic resonance (NMR). These have and it is inferred that tion of Mg17Al12 has taken place during aging in strength and the de- this has been the cause both of the increase crease in ductility. AM 11:35 on the Microstructure Study of the Effect of Heat Treatment AZ91Alloy and Mechanical Properties of a Thixoformed Evangelista Michael Talianker 4069 Australia which are relevant to the use of magnesium Data are presented and interior of automotive vehicles where alloys in the engine bay can reach 120 metal temperatures for typical applications 3 Sci. and Tech., Private Bag 33, Clayton, Victoria 3169 Australia; Bag 33, Clayton, Victoria Private Sci. and Tech., and Solid. Tech., Brisbane, Queensland 4072 Australia; Brisbane, and Solid. Tech., Australia; Australia; hardening and varying the strain K-value (570 MPa) with a single is obtained The n-value temper. according to the alloy exponent, n, n = 1.382- number with the expression hardness from the Vickers calculate yield strength as YS = 568.9 (0.002) 0.265 ln(Hv) and used to AM 11:10 Properties Aging on the Tensile The Effect of Low-Temperature Mg-Al Alloys of High-Pressure Diecast John R. Griffiths 883, Kenmore, QLD 4069 Australia QLD 883, Kenmore, at 165 aging time effect of The sand cast AZ91 alloy has been studied. The hardness, Hv, and yield Hv, The hardness, studied. alloy has been AZ91 sand cast ductility de- while the tensile increase with the aging strength, YS, to the flow curves of the material is possible to fit the creases. It equation

WEDNESDAY AM 137 and classicDCcasting hotcracksmayalsoform at thecentreline.In ample, surfacecracks mayappearwhenthepartly solid shellruptures, case ofhorizontaldirectchill(HDC) castingofmagnesium,forex- properties anddeformationofthe partiallysolidifiedmaterial.Inthe of thesealloys.Defectsinmany casting processesarerelatedtothe major productionstepitisimportant tounderstandthesolidification wide forapplicationinautomotive components.Becausecastingisa Magnesiumalloysarecurrently receivingsignificantinterestworld- Solid. Tech., Brisbane,Qld4072Australia Queensland, Dept.ofMing.,Min.andMatls.Eng.,CRCforAlloy & RaglanSts.,Preston,Victoria 3072Australia; Solidification Technology, CSIROManufact.Sci.&Tech., CnrAlbert loys Stress InducedDefectFormationinDCCastMagnesiumAl- 10:20 AM 10:10 simply restrictionofcrystalgrowthduringsolidification. the effectiveparticleswascatalysisofprimarycrystalnucleation or sium. However,itisnotclearwhetherthegrainrefiningmechanism of lattice disregistrybetweentheircrystalstructuresandthatofmagne- refinement, probablybecauseofenhancednucleationduetothesmall based alloys(AlN,Al4C3).Mostoftheseparticlesproducedgrain considered tobepowerfulnucleantsinAlbasedalloys(TiC)andMg grain refinementeffectofparticlesaddeddirectlytothemeltthatare tion effectsduringsolidification.Anattemptwasmadetoidentifythe refinement, probablybecausetheseelementshavehighgrowthrestric- Additions ofZr,Si,orCatopuremagnesiumproducedsignificantgrain strontium hadanegligibleeffect ongrainsizeintheMg-9Alalloy. grain refiningeffectinlow-aluminiumcontainingalloys.However, aluminium contentmagnesiumalloysshowedthatSrhadasignificant contents (above5wt%).Strontiumadditionstobothlow-andhigh- decrease ingrainsizeupto5wt%Al,andastabilisationathigherAl aluminium contentinhypoeutecticMg-Alalloysshowedacontinuous solute andparticleeffects.Thevariationingrainsizewithincreased loys hasbeenstudiedwithafocusongrainrefinementmechanisms, GrainformationduringsolidificationofmagnesiumandMg-Alal- Australia Solid. Tech., Ming.,Min.andMatls.Eng.,Brisbane,Queensland4072 David H.StJohn Grain RefinementofMagnesium 9:45 AM interdendritic porousnetworkdepletedinAlandZn. shrinkage creatinganinterdendriticflow, leavingbehindan in alloyingelementstendtobedrawnoutwardscolderregionsdue last. Thiscanbeexplainedbyinversesegregationasthemeltenriched porous AlandZndepletedregionscoincidewiththesolidifying porosity isfoundtorelatecloselythedistributionofAlandZn.The Porosity asfunctionoflocationintheingotshasbeenexamined,and regions. Impuritiesredistributeaccordingtotheirsolidsolubilities. gated. ItisfoundthatAlandZnarestronglydepletedincertain cross sectionsofmagnesiumalloyAZ91ingotshavebeeninvesti- tion shrinkage,willcausemacrosegregation.Elementdistributionover point eutectics,combinedwithpressuregradientssetupbysolidifica- phase. Inthelaterstagesofsolidification,presencelow-melting maximum solidsolubilitywillcontainacertainfractionofeutectic solidification, evenalloyswithaluminiumcontentswellbelowthe of aluminiumasthemainalloyingelement.Duetonon-equilibrium Magnesiumalloysfordiecastingarecommonlybasedonaddition MI USA 2 Westengen minium AlloyAZ91Ingots Solidification InducedInhomogenitiesinMagnesium-Alu- 9:20 AM rate, isdiscussed. tectic Mg-Al-Znalloys,anditsrelationtodependenceoncooling fication. Theeffectofzinconthesolidificationbehaviourhypoeu- were usedtoinvestigatethesegregatingbehaviourofzincduringsolidi- fied atthesamecoolingrate.DirectionallysolidifiedsamplesofAZ91 form whenagranulareutecticwasobservedinthebinaryalloysolidi- General Motors,GlobalR&DOperations,30500MoundRd.,Warren, :

John F. Grandfield Break 1 ; 1 Norsk Hydro,Rsch.Ctr., PorsgrunnN-3901Norway; 1 ; 1 The UniversityofQueensland,CRCforAlloyand 1 ; ArneK.Dahle : Per Bakke : Young C.Lee 2 1 ; ; CarlFuerst 1 CRC forAlloyand 2 1 The Universityof ; ArneK.Dahle 2 ; Hakon 1 ; fication, microalloying,productionofmodifyingagents,etc.). the proposalsonitsapplicationinothermetallurgicalprocesses(modi- and technologicalpropertiesofgranulatedmagnesiumformulates sium byelectrolysis.Thepaperalsopresentsmainphysico-chemical cost, withthegranulationunitlocatedatfacilitiesproducingmagne- of liquidmetalinamixturewithfluxisnotableforitlowproduction Main drawbackoftheproductisitshygroscopicity. Castingofgranules granulated magnesiumbyair-operatedtransportatsubstantialdistance. fluidity; 4.Fireandexplosionsafetywhichpermitsonetotransferthe particles withadiameterof0.4-1.6mm;2.Highbulkdensity;3.Good fireproof flux(saltadditive)areasfollows:1.Spheroidalshapesof granulated magnesiumproducedbycastingaliquidmetalmixedwith rial asareagentfordesulfurizationofhotmetal.Mainadvantages proof fluxhasrevealedbasicadvantagesandlimitationsofthismate- equipment andthequalityofmagnesiumgranulescoatedwithfire- trifugal sprayingofliquidmetal.Analysisindustrialoperationthe matic processflowdiagramfortheproductionofgranulesbyacen- ogy elaboratedintheTitaniumInstitute.Thepaperpresentsasche- the unitsforproductionofmagnesiumgranulesusingtechnol- magnesium alloysofAz80AZ91grades.Two plantsinChinaoperate mastered fortheproductionofmagnesiumgranulesfromsecondary pose, hasbeenrecentlyimproved.InUkraine,theprocess magnesium alloysdevelopedintheTitaniumInstituteforthispur- to hotmetal.Themethodforcastingthegranulesofmagnesiumand pure granulatedmagnesium(withoutsuchadditivesasCaOandCaCl2) known intheartisprocessfordesulfurizationbasedoninjecting America, Europe,andAsia.Themosteconomicalprocessofthose for hotmetaldesulfurizationiswinningnewmarketsinNorthern Magnesium,themostefficientandenvironmentallyfriendlyagent 330600 Ukraine Design TitaniumInstitute,180ProspectLenina,GSP-314,Zaporozhye tions Centrifugal SprayingofLiquidMetal:AdvantagesandLimita- Casting ofGranulatedMagnesiumandAlloysby 10:45 AM mechanisms ofthemushyzoneinmagnesiumalloysarediscussed. cal behaviourduringsolidificationondefectformation.Strengthening test data.Themeasurementsindicatethesignificanceofmechani- examinations ofHDCcastmaterialarecomparedtothehottensile dus temperature.Theresultsofsurfacecrackandcentreline remelted, puremagnesiumandMg-Alalloysabovebelowthesoli- predict thetensilepropertiesofsolidifying,aswellreheatedand to bedetermined.Work hasthereforebeenundertakentomeasureand erties ofthepartiallysolidifiedmaterial,particularlyintension,need order tounderstandandeliminatethesedefectsthemechanicalprop- : I. Barannik 1 ; V. Alexandrov 1 ; I.Komelin 1 ; 1 State Researchand

WEDNESDAY AM 138 ; ; 1 1 Don Weeks University of 2 Infineon Tech- : 1 ; 1 Berislav Momcilovic : IBM, T. J. Watson Rsch. Ctr., J. Watson IBM, T. 1 Institute for Medical Research and ; 1 1 ; 2 Guenter Schindlbeck : T. H. Zabel T. : ; Cody Nitschke Spectrum Sciences, 3050 Oakmead Village Dr., Santa Dr., Village 3050 Oakmead Spectrum Sciences, 2 1 ; 1 North Dakota, Grand Forks, ND 58202-7129 USA North Dakota, Grand Forks, ND 58202-7129 when alpha particles Soft errors in computer memory chips arise solder bumps change the from the radon daughter 210Po in the lead Certification of transistors in the memory. state of individual charge the 210Pb concentration in low alpha lead (LAL) is difficult, time We consuming and expensive at the levels required by the industry. used a microtome (American Optical Co., Buffalo, NY) to produce thin lead samples (1 to 5 microns) of relatively large area (> 7 cm2) so that a alpha flux from thin samples of large surface area could be measured. Attenuation of 210Po alpha particles (collimated beam) Oak from a plated source (0.1 microcurie, Spectrum Technologies, Ridge, TN) m were used to measure peak smearing and energy shift dependence upon lead thickness (676A Alpha-King Spectrometer, EG&G Ortec, Oak Ridge, TN). Lead slices one, and two micron thickness had respective peak broadening of 7 to 70 times and energy shifts than 2 microns produced broad, Lead slices thicker of 0.5 to 1.4 MeV. low intensity peaks with poor resolution. These data demonstrate the necessity to standardize the optimal lead thickness for uniform standardization of the measurement techniques among different laboratories. Supported in part by DEPSCoR under Research Proposal No. 40072-EL-DPS. AM 11:25 The Relative Counting Efficiencies of Zinc Sulfide and Gas Alpha Proportional Heights, NY 10598 USA Box 128, Rt. 134, Yorktown P.O. Several different methods of measuring alpha particle emission from materials used to manufacture semiconductors have been developed. Occupational Health, P.O. Box 291, Zagreb Croatia; Box 291, Zagreb Occupational Health, P.O. 9:40 AM Break 9:40 AM AM 9:55 Con- Emitting Particle of Alpha and Analysis The Detection Materials in Semiconductor Packaging taminants Mike Tucker USA Clara, CA 95051 discovered by soft error was alpha particle induced Semiconductor Since that late 1970’s. at Intel in the Woods May and Murray Tim techniques particle counting have been several nuclear time, there semiconductor packaging materials for alpha developed to monitor Methods of surface analysis, bulk analysis and emitting radioisotopes. ac- be discussed. Emphasis will be placed on alpha spectroscopy will techniquesfor evaluating Flip Chip and BGA ceptable measurement lead solder related processes. 10:25 AM Ensuring Alpha Counting Box 800949, Munich 81609 73, P.O. nologies, MPQ, Balanstrasse Germany the follow Poisson distributions. The slope of Alpha counting rates de- (CDF) of a Poisson distribution only cumulative density function This fact can be used for simple graphical pends on its mean value. to The first example demonstrates, how checks of counting rates. above 20. With the check a series of counting rates with mean values which was added to second example a systematical error was detected, distribution. Analysing the purely statistical fluctuations of a Poisson rates, daily alterations the chronological distribution of the counting The tubes of the gas and a superpositioned weekly cycle was found. the tubes, this problem supply had caused the problem. By replacing 10 a modified method is could be solved. For mean values below 5 to A table of alpha rates presented for checking series of counting rates. with the methods de- is presented. All measurements were checked 0.0005 to more than scribed above. The alpha rates vary from about One counting tube was 100 alphas per square centimeter per hour. rate showed a different investigated in detail. Its background counting A clear efficiency. dependency on bias voltage, than the counting divided by efficiency) minimum of the relative background (background plateau. This bias point showed up near the lower edge of the alpha represents the optimum operating condition. 10:55 AM Alpha Particle Emis- Micron Slices of Lead for Assessment of sions in Computer Chip Manufacturing Glenn I. Lykken 3 CO Ron 2 Glenn : : Po. Antiquity and 0.2 g of 3 210 Pb in lead on the CO 2 210 University of North 1 Institute for Medical 2 ; Pb activity in lead was 2 210 Yellapu V. Murty, Carpenter Technol- Carpenter Murty, V. Yellapu Pb and other radiocontaminants in lead and Room: Lincoln C Location: Opryland Convention Center ; Berislav Momcilovic 210 1 Pb in lead will be compared, and a practical limit 210 Martin Weiser, AlliedSignal Electronic AlliedSignal Martin Weiser, Electronic, Magnetic & Photonic Materials Magnetic & Photonic Electronic, Battelle, Pacific Northwest Nat. Lab., Richland, WA Battelle, Pacific Northwest Nat. Lab., Richland, 1 ; 1 ; Ben Ziegler 1 I. Lykken and powdered graphite contained 210Po and so does the smelted lead from previously low 210Pb galena. Polonium-210 alpha particle emissions were measured with a 676A Alpha-King Spectrometer, EG&G Ortec, Nashville, TN. Supported in part by DEPSCoR under Research Proposal No. 40072-EL-DPS. Brodzinski Dakota, Grand Forks, ND 58202-7129 USA; Box 291, Zagreb, Croatia Research and Occupational Health, P.O. Lead ore (galena) is originally very low in 210Pb whereas lead processed from galena may have amounts of 210Po high enough to processed a low 210Pb generate soft errors in computer chips. We galena (Doe Run, Co., Herculaneum, MO) in a small-scale standard reduce the melting point of smelting method (Heraeus, patented). To galena, 2.5 g of galena were mixed with 2.5 g Na powdered graphite as a reducing agent in a graphite boat. Both Na for alpha activity in lead will be proposed. 9:10 AM From “Clean” Galena to “Contaminated” Lead-Why? found to create significant background in a low-background radiation found to create significant background in a alpha particles emitted Shortly thereafter, detection spectrometer. observed with this from the surface of a solder joint were directly It was further observed that these alpha particles had spectrometer. by the melting process, been concentrated on the surface of the solder of and that they decayed with the energy and half-life radioactive background. lead was used to eliminate these sources of up to these “discoveries” The experiments and developments leading will be described. The magnitude of the effect of experiment will be discussed. The current sensitivity of these spec- trometers for detecting other materials will also be presented. The sensitivity of various techniques for measuring 99352 USA More than 15 years ago the presence of 8:30 AM Opening Comments 8:40 AM Invited and Solder The “Discovery” of Alpha Activity in Lead March 15, 2000 Session Chair: Wednesday AM Wednesday 99216 USA Materials, Spokane, WA Sponsored by: Sponsored and Interconnection Electronic Packaging Division, Materials Committee Organizers: Program and Development, Reading, PA ogy Corporation, Research Godavarti, Motorola, Austin, TX 19612-4662 USA; Prasad Jin, Bell Laboratories, Lucent Tech- 78721 USA; Sung-Ho J. NJ 07974 USA; Sung Kang, IBM, T. nologies, Murray Hill, NY 10598 Heights, Yorktown Research Center, Watson US Competitors, LLC., Newark, DE USA; John Macwilliams, Fujitsu Computer Packaging 19711 USA; Mark McCormack, Weiser, San Jose, CA 95134; Martin Technologies, and Discrete AlliedSignal Electronic Materials, Plated 99216 USA Products, Spokane, WA Materials Issues in Microelectronics: Issues Materials Alpha and Thermal: Electrical, Optical, Issues in Microelectronics Particle Packaging

WEDNESDAY AM 139 of build-upandbreak-down ofthesolidskeleton.The modelisimple- scribed byafirstorderkineticdifferential equationthatrelatestherate processing history. Theevolutionofthestructuralparameterisde- solid volumefraction,andofastructural parameterthatchangeswith model. Therheologicalparameters areassumedtobefunctionsofthe modeled usingconservationequations andtheHerschel-Bulkleyfluid investigation, thebehaviorofsemisolid slurriesduringprocessingis structure breakdownandincrease with itsdevelopment.Inthepresent material, suchaseffectiveviscosityandyieldstress,decreasewith As aresultofthesekineticprocesses,therheologicalproperties the number ofkineticphenomenadifferentcharacteristictime-scales. and thermalhistoryofthematerial,itsevolutionisgovernedby a skeleton isalmostneveratequilibrium.Itdependsonthemechanical skeleton formedbythealphaphaseparticles.Thestructureof the ior oftheslurryisdeterminedbystructureandproperties the rounded rosette-likecrystalsineutecticliquid.Themechanicalbehav- thixocasting, semisolidslurriesarehighlyconcentratedsuspensions of and characteristicscomparabletothoseofforgedalloys.During ogy offerbettermechanicalpropertiesthanthoseproducedbycasting zone, andtheninjectedintoadie.Partsproducedusingthistechnol- cially preparedbilletsarereheatedtoatemperatureinthemushy trend inmetalprocessing.Aspartoftheprocess(thixocasting),spe- Processingofmetalalloysintheirmushystaterepresentanew Russia of RussianAcademyScience,Pr. Vernadskogo 101,Moscow117526 Rd., Worcester, MA01609USA; tute, SemisolidMatl.Process.Lab.-Met.Instit.,100Institute Gilmer R.Burgos Modeling ofSemisolidMetalCasting 8:30 AM Lafayette, IN47907USA Krane, PurdueUniversity, Sch.ofMatls.Eng.,West Iowa, Dept.Mech.Eng.,IowaCity, IA52242USA;JohnM. Session Chairs: March 15,2000 Wednesday AM Engineering, MIdM-89,Cincinatti,OH45215USA Edmonton, ABT6G2G6Canada;SulekhJain,GeAircraft MN 55414-2196USA;HaniHenein,UniversityofAlberta, Minnesota, SaintAnthonyFallsLaboratory, Minneapolis, Program Organizers: Modeling Analysis&ControlCommittee Processing andManufacturingDivision,Jt. Sponsored by: Modeling Age III:SolidificationandProcess Materials ProcessingintheComputer results. suppliers oflowalphaPbandrelatedmaterialscanobtainmorereliable results fromthesetwomeasurementtechniquessothattheusersand relative counterefficiencies. Finally, Iwilldiscusshowtocorrelatethe compare thephysicalmodelstoexperimentaldatadetermine tional countersandhowthisimpactsthemeasurements.Itwillthen talk willdiscussthephysicsbehindbothzincsulfideandgaspropor- ported alphaemissionbetweendifferentmeasurementtechniques.This has becomemoreimportanttounderstandthediscrepanciesinre- bumps requirematerialswithloweralphaemissionrates.Asaresult,it mate contactwiththepotentialalphaparticleemitterssuchassolder surements madeonthesamesample.Smallerdevicesandmoreinti- These differentmethodsoftenproduceinconsistentresultsformea- 1 Extraction &ProcessingDivision,Materials ; VladimirM.Entov Christoph Beckermann,Universityof Location: OprylandConventionCenter Room: LincolnA Vaughan Voller, Universityof 2 Institute forProblemsinMechanics 2 ; : 1 Worcester PolytechnicInsti- Andreas N.Alexandrou 1 ; Laurentiu Nastac in theCentrifugalCastingofMetal-Matrix-Composites A ComputerModelforSimulationofMulti-ScalePhenomena 8:50 AM their effectonprocessingisanalyzed. metric studyisperformedwithdifferentrheologicalconstantsand mented intoacomputercodetopredictdiefilling.Anextensivepara- 8000 W. SunriseBlvd.,Ft.Lauderdale, FL33324USA Chester, VA 23831USA; Metals Company, Corp.Rsch.andDev., 13203N.EnonChurchRd., Ingot-Differences in Comparison oftheTransient Phaseinan Aluminum Start-Up 9:50 AM associated qualityproblems. sient, asymmetricflowinthecontinuous slab-castingmoldandthe These modelsarebeingappliedtosimulatethree-dimensional,tran- veloped, thatdirectlysimulatetheimportantlarge-scalestructures. predict thesephenomena,largeeddysimulationmodelsarebeing de- that ariseduethechaoticturbulentmotion.To improvetheabilityto ently inaccurateatpredictingtheintermittent,transientflowevents Reynolds-averaged modelsofturbulentflow, suchasK-e,areinher- level fluctuations,inclusionandbubbleentrainment.Conventional very importanttothegenerationofqualityproblems,suchassurface Duringthecontinuouscastingofsteel,transientfloweventsmay be St., Urbana,IL61801USA Vanka ing ofSteel Large EddySimulationofTurbulent FlowinContinuousCast- 9:30 AM Mg systemandcomparedwithpublishedresults. lated profilesarepresentedforthealuminumrichregionofAl-Cu- composition andtemperaturevariationsduringsolidification.Calcu- associated withanopensystemandpossibleremeltingduetomixture primary andsecondaryphases.Themodeladdressesthecomplications nent ofseveralaluminumrichternaryalloysareobtainedforthe lidification ofternaryalloys.Compositionprofileseachcompo- Amodelisdevelopedtosimulatemicrosegregationduringtheso- USA School ofMatls.Eng.,1289MSEEBldg.,West Lafayette,IN47907 Michael R.McLane Microsegregation inTernary AlloyswithanOpenSystem 9:10 AM of theU.S.NavyManufacturingTechnology Program. tion undercontractNo.N00140-92-C-BC49totheU.S.Navyaspart working Technology, operatedbyConcurrentTechnologies Corpora- work wasconductedbytheNationalCenterforExcellenceinMetal- data forcentrifugally-castA356/SiCandTiC/Al-bronzealloys.This ticle distributionandmicrostructurewerevalidatedwithexperimental trix-composites wasalsoinvestigated.Themodelpredictionsofpar- ture andinsolubleceramicparticlesincentrifugally-castmetal-ma- ated indetail.Thecomplexinteractionbetweenthesolidifyingstruc- ing clustersandagglomerates)ontheparticledistributionwereevalu- of thevolumefraction,size,andmorphologyparticles(includ- material parametersonthedistributionofTiCparticles.Theeffects the computermodeltoinvestigateeffectsofvariousprocessand solidifying microstructure.Parametricstudieswereconductedusing pingement effectofparticlesonthenucleationandgrowthkinetics centration, andcoolingrateonthefinalgrainsize,(5)im- equiaxed andeutecticphases,(4)effectsofparticlesize,con- by theadvancingsolid/liquidinterface,(3)nucleationandgrowthof engulfment (entrapment)orpushingofparticlesinthemushyregion viscosity modeloftheinterferencebetweenmovingparticles,(2) cation kinetics.Themodeladdressesthefollowing:(1)arheology- analysis tobedominatedbycentrifugalbuoyancyeffectsandsolidifi- proper distributionofTiCparticles,whichisshownbydimensional bronze frictiondrums.Performanceofthesecomponentsrequires optimize thecentrifugalcastingprocessformanufacturingTiC/Al- Acomprehensivecomputermodelwasdevelopedtounderstandand 100 CTCDr., Johnstown,PA 15904-1935USA rent Technologies Corporation,Manu.Tech. Direct./Proc.Anal.Dept., 1 ; 1 University ofIllinois,Mech.&Indust.Eng.,1206W. Green : Sivaraj Sivaramakrishnan 1 ; JuanJ.Valencia 1 : ; Matthew JohnM.Krane Daniel PaulCook 2 Motorola Inc.,Phys. Proto.andTool. Ctr., 1 ; JundeXu 1 ; 1 ; W. KinzyJones Brian G.Thomas 1 ; HaoDong 1 ; 1 Purdue University, 2 ; 1 ; 1 Reynolds 1 1 ; Pratap Concur- : :

WEDNESDAY AM 140 ; : 1 Bell Labo- 1 ; 1 Karl F. Seelig Karl F. ; 1 Michigan State University, ; Sungho Jin 1 1 ; 1 David K. Suraski : Hareesh Mavoori, Bell Laboratories, Hareesh Mavoori, Bell Hareesh Mavoori Room: Lincoln D Location: Opryland Convention Center : K. N. Subramanian S. Jin, Lucent Technologies, Murray Hill, S. Jin, Lucent Technologies, C. Thermomechanical fatigue (TMF), caused by ; ° 1 Electronic, Magnetic & Photonic Materials Electronic, Magnetic ; J. Lucas 1 AIM Inc., Tech. Dept., 25 Kenney Dr., Cranston, RI 02920 USA Dept., 25 Kenney Dr., AIM Inc., Tech. 1 8:30 AM Invited and Opto- Dimensionally Stable Solders for Microelectronic electronic Applications Packaging & Soldering Technologies Packaging & Interconnects: Reliability for Electronic of Bulk Solders Sponsored by: Packaging and Interconnection Division, Electronic Materials Committee Program Organizers: USA; Srini Chada, Motorola, Planta- Murray Hill, NJ 07974 Gautam Ghosh, Northwestern Univer- tion, FL 33322 USA; Evanston, IL 60208- Department of Materials Science, sity, AlliedSignal Electronic Materials, 3108 USA; Martin Weiser, 99216 USA WA Plated and Discrete Products, Spokane, AM Wednesday March 15, 2000 Session Chairs: University, NJ 07974 USA; R. A. Fournelle, Marquette Milwaukee, WI 53201 USA Murray Hill, NJ 07974 700 Mountain Ave., ratories, Lucent Tech., USA deformation caused Solders are generally prone to time-dependent due to their low by phenomena such as creep and stress-relaxation temperatures. Such melting points and high homologous operating in certain optoelec- dimensional instabilities could lead to failures of optical alignment, tronic and microelectronic devices through loss In light of the ever-in- electrical isolation, or mechanical failures. it is desirable to have creasing device miniaturization and complexity, due to creep and solders that are resistant to changes in dimensions present two approaches towards mini- microstructural instabilities. We mizing creep in solder bonds: (1) an oxide-dispersion based approach to improve the creep-resistance and microstructural stability of the solder itself, and (2) an alloying approach that dramatically improves the interfacial bonding, thereby eliminating many of the stability problems related to solder bonding of optical or microelectronic components. 9:00 AM Invited Thermomechanical Fatigue Behavior of Sn-Ag Solder Joints S. Choi Dept. of Mat. Sci. & Mech., East Lansing, MI 48824-1226 USA Solder joints in electronic packages experience thermal cycling due to temperature fluctuations encountered in service. In automotive under-the-hood applications extreme temperatures could range between -40 to 150 stresses developed from CTE mismatch during thermal cycling, is one of the most important contributor to solder joint failures. Microstruc- ture evolution, and the fracture behavior, in Sn-Ag solders under thermal cycling conditions will be discussed. 9:30 AM Solders A Study of Lead Free to protrusion of iron fingers from the cathode into the slag, capillary the slag, into from the cathode iron fingers of to protrusion fingers breaks the force uneven Lorentz by accelerated instabilities a Rayleigh in slag produces suspended dense iron and into droplets, are explored scales their time/length and These instabilities instability. limitations to of operation and understand the regimes in order to model- the way to future numerical rate, and to pave overall reaction optimization. for cathode design ing of the process : ; 2 Ford Motor 1 The University ; 1 1 ; Uday B. Pal 1 ; 1 ; Ravi Vijayaraghavan ; Ramana G. Reddy Boston University, Manu. Eng., 15 St. Boston University, 1 1 2 Adam Clayton Powell : ; Banqiu Wu 1 John E. Allison : MIT, Matls. Sci. and Eng., 77 Massachusetts Ave., Rm. 4-117, Cam- Rm. 4-117, Matls. Sci. and Eng., 77 Massachusetts Ave., MIT, bridge, MA 02139-4307 USA; 1 Mary’s St., Boston, MA 02446 USA Mary’s In electric field-enhanced smelting and refining of iron and steel, reaction rate is controlled by iron ion diffusion through slag to the cathode, thus understanding of the kinetics at the cathode is important to improving the process. In addition, under some conditions, molten iron forms a conductive path through the slag, resulting in vastly lower efficiency; this underscores the importance of understanding the phenomena here. However, the evolution of molten iron in slag gives rise to multiple coupled instabilities: the Mullins-Sekerka instability leads of Alabama, Dept. of Metallu. and Matls. Eng., P.O. Box 870202, Eng., P.O. of Alabama, Dept. of Metallu. and Matls. Tuscaloosa, AL 35487-0202 USA A mathematical model was developed to describe the plasma gas and particle dynamics and conversion yields. The velocity and temperature fields in the plasma were calculated by solving the Navier-Stokes equations and the thermal energy balance equations. Conservation equations for the system species consider the multi-component diffusion and chemical reactions. The model was used to study the thermal decomposition of ilmenite in the non-transferred arc plasma reactor. Through the application of these models, concentration, temperature and flow fields were computed. AM 11:10 Scaling Laws and Instabilities in Electric Field Enhanced Smelt- ing and Refining of Iron Company, Ford Rsch. Lab., MD 3182 SRL, Dearborn, MI 48124-2053 Company, USA which will have In the next ten years the materials developments automotive industry will the most significant economic impact on the in existing be those which lead to refinements and improvements materials science materials and processes. Advances in computational materials, processes and will play a pivotal role in this optimization of analytical approach components. This talk will overview an integrated as progress in achieving to optimization of aluminum castings as well castings will be designed, this goal. Our vision is that virtual aluminum all on a workstation. cast, heat treated and complete durability testing, metal flow and thermal In addition to a robust knowledge of molten which accurately predict microstructural evolution models history, along with models relat- during casting and heat treatment are required and failure criteria. ing these microstructures to mechanical properties reviewed for the Al-Si-Cu Recent progress in each of these areas will be including models alloys typically used in automobile engine structures, aging response, and the for phase equilibria and microsegregation, properties. A num- influence of microstructure on tensile and fatigue and will be discussed. ber of unsolved problems have been identified 10:50 AM Plasma Reactor Modeling of Materials Synthesis in Thermal Sutham Niyomwas With the ever-increasing power of desktop computers, simulation desktop computers, power of the ever-increasing With Few re- metallurgist. today’s tool for an indispensable has become own develop their luxury to time or have the however, searchers, and in the number, increase lead to a large this has code and numerical software packages. These commercially available of the complexity, “black-box” not yet reached the software packages have commercial for and relatively easy-to-use they are both bug-free stage, i.e. where will discuss In this paper, we new to the field of simulation. researchers distributed purpose CFD codes of two popular general bench marking element method, is based on the finite which FIDAP, by Fluent, Inc., uses finite volumes to discretize the compu- and FLUENT-UNS, which of these codes were used to model the transient tational domain. Both direct chill casting of aluminum. Tempera- start-up phase in vertical, a multiple casts of a Al-1%Cu alloy and ture data was taken during to was developed. This data was then used thermal profile of the ingot models and compare the solution method- validate the mathematical of computational re- comparisons Finally, ologies used in each code. code will be presented. sources necessary for each 10:10 AM Break 10:30 AM and Product for Process Aluminum Castings: A Tool Virtual Optimization

WEDNESDAY AM 141 to formsoldersballs. Microstructuralobservation ofthesolderballs punched-out. The solderdiskswereremeltedinacolumn ofsiliconoil The ingotswerehotrolledintothin sheetsandfromwhichdiskswere tion processbetweenCupowderand themoltensolder,wereproduced. forced withCu devices. Inthisstudy, Sn-PborSn-Agmatrixcompositesolders rein- stability ofthesoldersiscrucial forthereliabilityofelectronic der ballsinrecentpackagessuch asinChipScalePackages,thermal electronic deviceassociatedwiththeemploymentofsmallersizesol- Withtheever-increasingheatreleaserateperunitvolumeof the 701 Korea Electronics Company, DeviceandSemicond.Rsch.Div., Ichon467- Matls. Sci.,Mapo-GuSangsu-Dong72-1,Seoul121-791Korea; Yong-Ho Lee In-Situ Process Reliability ofIn-SituCompositeSolderBumpsProducedby an 11:10 AM results. reliability ofthesolderjointsisdiscussedinviewcreeptest solder alloy. Theroleoftheintermetallics(Cu-SnandAg-Sn) inthe compared withthedataobtainedforsamplesmadeofSn-3.5Agbulk creep test(thekineticdataaswellmicrostructuralchanges)are Sn-Ag intermetallicsinthematrixarepresented.Theresultsof on thethicknessofCu-Snintermetallicslayeranddistribution tests atdifferenttemperaturesandappliedstresses.Thekineticdata 3.5Ag soldertomodelrealjoints.Thesamplesunderwentcreep Inthiswork,speciallydesignedCucouponsweresolderedwithSn- ON Canada tems, Dearborn,MIUSA; Canada; ing LaboratoryInc.,4925Dufferin St.,NorthYork, ONM3H5T6 Ulysse Michon der JointsduringCreep Characterization ofMicrostructuralEvolutioninSn-3.5AgSol- 10:45 AM perature applications. basis forselectionoftheoptimumleadfreesolderelevatedtem- tests undervaryingtemperatureandstrainrateconditionsprovidea characterized leadcontainingsolders.Theresultsofthemechanical plug jointsweremadewith12selectedlead-freesoldersand2well tions, andsustainedtemperaturesofupto125 the solderjointsaresubjectedtomanythermalcycles,severevibra- avionics, automotiveelectronics,andindustrialapplicationswhere hancements ofthesepropertiesandretainssolderabilityiscrucialin creep andtothermal-mechanicalfatigue.Asolderwhichexhibitsen- solders. Currentleadedsolderslackshearstrengthandresistanceto problems concerningthemechanicalpropertiesofSn-PbandPb-based Free solderalloys.Inadditiontothetoxicityoflead,thereareother in industrialapplicationshasspurredthedevelopmentofnewLead- Theglobaldrivetoreplacetheuseoftoxicleadmetalanditsalloys P.O. Box96,Princeton,IA52768USA 50011 USA; 1 Lead FreeSolders Analysis ofRingandPlugShearStrengthsforComparison 10:15 AMInvited 9:55 AMBreak ent alloyscomprisedoftin-copper-silver. will benewdataoncreepatfourdifferenttemperaturesandtwodiffer- copper, andtin-silver-copperalloys.Includedinthesecomparisons alloy. Highlightedinthiswillbeacomparisonofthetin-silver, tin- compare themtooneanother,aswellthetraditionaltin-lead of theseisnecessary. Thispapershalldiscussthesevariousalloysand different insignificantwaysandbackgroundinformationabouteach eliminate leadfromtheirprocesses.However,eachlead-freealloyis research havegoneintofindingaviablesolutionforthosewhowantto options totheboardassembler. Muchdevelopment,patterning,and push tofindlead-freesolderalternativesisthattherenowaremany has beentargetedintheelectronicsassemblyarena.Oneresultof Withtheongoingconcernregardingenvironmentalpollutants,lead Ames Laboratory, Metallu.&Cer. Pgm.,122MetalsDev., Ames,IA 2 ESPEO, Orleans,CedexFrance; 2 1 Johnson ManufacturingCompany, 114 LostGroveRd., ; Yong-Seog Kim 2 6 ; DonkaiShangguan Sn : 5 : dispersoids,whichwasformedvia anin-situreac- Jong-Hyun Lee James C.Foley : 4 Visteon AutomotiveSystems,Markham, Vladimir I.Igoshev 1 ; 1 1 ; Dae-JinPark 3 1 Hong IkUniversity, Metallu.and ; StephenWong ; AlanGickler 3 Visteon AutomotiveSys- ° C. Modifiedringand 1 ; 1 2 Jacob I.Kleiman ; Jong-Tae Moon ; LarryLeProvost 4 ; 1 Integrity Test- 2 Hyundai 2 1 2 ; ; ; Froes, UniversityofIdaho,Moscow, ID83844-3026 USA Session Chairs: March 15,2000 Wednesday AM Yu, RMICorporation, R&D,Niles,OH44446-0269USA USA; IsaacWeiss, JohnsonMatthey, USA;KuangOscar Idaho, IMAP-MinesBldg.#321,Moscow, ID83844-3026 Albany, OR97321USA;F. H.(Sam)Froes,Universityof Program Organizers: Shaping andFormingCommittee Division, StructuralMaterialsTitaniumCommittee, Sponsored by: Its Alloys:SessionIII Production &ProcessingofTitanium Process SynthesisandModelingforthe the compositesolders. face oftheeutecticsolder/substrateinterface,wasnotdevelopedwith thermal treatmentsandthePb-richlayer,whichformsnearinter- the soldersshowedverylittlegrowthofreinforcementsafterthose ter propertiesthanthoseofmatrices.Microstructuralobservation -65°C. Inthosetests,thecompositesoldersshowedconsistentlybet- aging at120 various thermalhistories,whichincludereflowsolderingupto4times, nace ofconvectionheatingandtheshearstrengthweremeasuredafter soldering oftheballsonaBT-resinsubstratewasconductedinfur- indicated thatthesizeofreinforcementsisabout2mm.Reflow differential thermalanalysis(DTA) andX-raydiffraction technique mations takingplaceinthesystem duringheatingwasstudiedutilizing agent (PCA)andcontaminationcaused byit.Natureofphasetransfor- blended withtitaniuminorderto avoidtheuseofprocesscontrol and heattreatment.Someamount oftitaniumhydride(TiH1.924)was (BE) powderapproachinconjunction withmechanicalalloying(MA) AlowdensityTi-Si-Alalloywas synthesizedbyblendedelemental Mines Bldg.R321,Moscow, ID83844-3026USA Oleg N.Senkov Synthesis ofaLowDensityTi-Si-AlAlloy 8:55 AM kinetics withchangesinprocessingparameters. process insidethereactorandallowsustopredictchangesinreaction mentally verified.Themodelgivesanapproximationoftheactual powder ratioonthereactionkineticshavebeenevaluatedandexperi- time. Inaddition,theeffectofchargeratio,pre-millingandball-to- of ‘eventprobabilities’whichrelatestothefractionsreactedwith Courtney’s model.Thekineticsofthesynthesisareexpressedin terms Mg) inplaceoftheidealsolid-solidcombinationsconsidered in mixture (LiquidTiCl4+SolidAlCl3ReducingAgentCaH2and The presentmodeltakesintoconsiderationtheliquid-solidreactant state displacementreactionsduringthemechanochemicalsynthesis. count thechemicalreactionsthatoccursimultaneouslywithsolid- by hypothesizinganintermediateactivatedcomplextotakeintoac- nomenological modelformechanicalalloyingandhasbeenextended mechanochemical synthesis.ThemodelisbasedonCourtney’s phe- formation oftitanium-aluminumalloysinnanocrystallineformby Amechanisticmodelhasbeendevelopedtostudythekineticsof Idaho, Dept.ofMetallu.andMin.Eng.,Moscow, ID83844-3026 USA cess., 321MinesBldg.,Moscow, ID83844-3026USA; (Sam) Froes Ti BasedMaterials Modeling oftheMechanochemicalProcessforSynthesis 8:30 AM 1 ° ; C for210hours,andthermalcyclingbetween+150 1 University ofIdaho,Instit.forMatls.andAdv. Pro- 1 ; F.H. (Sam)Froes Materials ProcessingandManufacturing : Isaac Weiss, JohnsonMatthey, USA;Sam Swati Ghosh Location: OprylandConventionCenter Room: KnoxvilleB James A.Hall,Oremet-Wah Chang, 1 ; E.G.Baburaj 1 ; 1 University ofIdaho,IMAP, : 1 ; K.Prisbrey Mutlu Cavusoglu 2 University of 2 ; F. H. 1 ;

WEDNESDAY AM 142 ; 1 ; E. 1 Fathi Habashi C. Finite element C. The strain rate C. The ° V. K. Berdin V. ° : : University of Ancona, Mech. Dept., University of Ancona, 2 C and 405% at 1200 C and ° Renato G. Bautista, University of Room: Lincoln E Location: Opryland Convention Center C improvements in the microstructural homo- in the microstructural C improvements o Renato G. Bautista, University of Nevada, Light Metals Division, Reactive Metals Institute for Metals Superplasticity Problems, 39 Institute for Metals 1 ; 2 Laval University, Dept. of Min. & Metallu., Quebec City G1K7P4 Laval University, Committee Program Organizers: and Metal Engineer- Nevada-Reno, Department of Chemical Mishra, Colorado ing, Reno, NV 89557-0136 USA; Brajendra Metals, School of Mines, Kroll Institute for Extractive Golden, CO 80401-1887 USA AM Wednesday March 15, 2000 Session Chairs: Metallu. and Matls. Eng., Reno, NV 89557 USA; K. Osseo Dept. of Matls. Sci. Asare, Pennsylvania State University, 16802 USA and Eng., University Park, PA Evantelista Science Rare Earths and Actinides; Rare IV: and Applications Technology Earths I Extraction Sponsored by: 8:30 AM Robert Bunsen and the Rare Earth Industry 1 Canada Robert Bunsen (1811-1899) the German chemistry professor most famous for the burner, he invented and now used in most laboratories, Bunsen’s played an important role in initiating the rare earth industry. laboratory was a meeting place for chemistry students from all over students who came to Bunsen played a particular role in Europe. Two the history of the rare earths. They were Jons Fridrik Bahr (1815- The 1875) from Uppsala and Carl Auer (1858-1929) from Vienna. first brought with him samples of rare earths’ minerals for analysis by newly invented spectroscope. The second was asked by Bun- Bunsen’s sen to study further the different spectra of rare earths extracted from went through a maximum when strain rate decreased. The elongation rate decreased. strain when through a maximum went at 900 was achieved of 165% 0.16 to from with temperature increased flow stress of the sensitivity de- it only slightly and range studied, temperature the 0.30 within flow was energy of the plastic strain rate. The activation pended on features Because of microstructural to be Q=347 kJ/mol. determined non-homoge- the deformation was mechanical alloying, resulted from alloy at low behavior of the led to the non-superplastic neous that tempera- the deformation temperatures. With increasing deformation 1100-1200 ture up to in substantial ductility improvement. geneity occurred resulting 10:50 AM of Diffusion Bonding at a Periphery Part Mechanical Modeling Alloy Out of Ti-6Al-4V Flat Disks of Two Russia; Khalturin St., Ufa 450001 Anacona Italy Bonding (DB) mainly depends on tem- It is known that Diffusion In applied on local volume of joining surface. perature, time and stress between loading scheme and stress state addition, the interrelations be joined, affects microstructure and mechani- resulted on the area to product. Diffusion bonding at periphery cal properties of the bonded diameter and 4.0 mm in of two Ti-6Al-4V flat discs, 190.0 mm in at 930 thickness, was conducted in a vacuum furnace predict the stress-strain modeling, FEM, (ANSYS 5.3), was used to were determined by a state on the joining zone. Material properties mechanical tests. On the visco-plastic constitutive law derived from and mechani- basis of FEM analyses, microstructural and fractography between load- cal investigations of the welded zone, the interrelation was established. ing scheme and properties of the formed joint ; 1 Uni- C to 1 . The ° O. N. Mutlu -1 ; : s 1 : -1 C was car- ° C while heating ° Kansai University, 1 to 1.7x10 University of Idaho, C, only two stable C, only two 1 ° -5 ; Shin-ya Komatsu ; 1 1 ; 1 ; F. H. (Sam) Froes ; F. 2 C of an amorphous mechani- ° ; Toru Imose ; Toru Institute for Metals Superplasticity 1 2 Masahiko Ikeda ; F.H. (Sam) Froes ; F.H. : 1 C and resulted in formation of TiAl and fur- in formation of TiAl C and resulted ; G. A. Salishchev ° 2 C and strain rate range of 8x10 ° ; Hiroyuki Shiota 1 C, some silicon, aluminum and titanium still remained in still remained titanium aluminum and silicon, C, some ° C. Decomposition of the amorphous phase was observed of the amorphous C. Decomposition ; Oleg N. Senkov ° 1 C to 1200 ; M. R. Shagiev 1 ° C, 30 ksi for two hours. After MA, a supersaturated solid solution C, 30 ksi for two hours. After MA, a supersaturated ° decrease internal stresses and cut in flat samples for tensile testing. mechanical properties were studied within a temperature range Tensile of 800 cally alloyed powder. The compact was then annealed at 900 cally alloyed powder. deformation curves were typical to the high temperature behavior of the material, with hardening, softening and steady-state stages. Elon- gation of the samples increased with an increase in temperature and Problems, Russian Acad. of Sci., Ufa 450001 Russia A Ti-47Al-3Cr (in at.%) alloy with a grain size of 140nm was produced by hot isostatic pressing at 950 versity of Idaho, Instit. for Matls. and Adv. Process., 321 Mines Bldg., Process., 321 versity of Idaho, Instit. for Matls. and Adv. ID 83844-3026 USA; Moscow, IMAP, Mines Bldg., Rm. 321, Moscow, ID 83844-3026 USA Mines Bldg., Rm. 321, Moscow, IMAP, by hot isostatic pressing A low density Ti-Mg-Si alloy was produced and blended elemental powders (HIP) of mechanically alloyed (MA’d) the weight proportion of (BE) powders. Ti, Mg and Si were blended in and TiH1.924 of Ti In some experiments a mixture 20:3:2 respectively. control agent (PCA), was used in order to eliminate the use of process HIP’ing was performed at stearic acid, and contamination caused by it. 700 where TiH1.924 was of Mg and Si in Ti or Ti + TiH1.924 (in batches was formed. XRD used) was produced and a nanocrystalline structure revealed Ti and Mg- phase analysis of HIP’d compacts of BE powders phase was present in 2Si as the major phases. However only a titanium powders. Annealing up to 1150 HIP’d compacts of MA’d and MgO in both compacts. Ti5Si3 resulted in Ti, ried out using DTA, Optical (OM) and transmission electron microscopy (TEM) was used for microstructural analysis. TEM analysis showed very fine nanometer sized grains structure in HIP’d and annealed compacts produced powders. The results obtained showed a possibility of pro- from MA’d duction of a low-density titanium alloy with high concentrations of magnesium and silicon with a nanocrystalline structure. Mechanical properties of the alloy are being investigated. 10:25 AM Mechanical Properties of a Nanocrystalline TiAl Alloy Pro- duced by Mechanical Alloying and Hot Isostatic Pressing Dept. of Matls. Sci. and Eng., 3-3-35, Yamate-cho, Suita, Osaka 564- Eng., 3-3-35, Yamate-cho, Dept. of Matls. Sci. and 8680 Japan Ti- and tensile properties were investigated on Beta phase stability e/a, 4.28 in solution treated and quenched Fe-Cr alloys having constant the resistivity measurement and tensile test. In (STQed) state through hardness decreased with increasing and Vickers STQed state, resistivity temperature depen- Cr substituted for Fe, though maintaining negative From these results, it is considered that beta phase dence of resistivity. substitute for Fe. With stability increased with addition of Cr as a decreased down to addition of Cr, though tensile strength slightly about 20%. Balance be- about 900MPa, elongation increased up to was improved by addi- tween the tensile strength and the elongation tion of Cr. 9:45 AM Break 10:00 AM Ti-Mg-Si Alloy Microstructural Properties of Low Density Cavusoglu Senkov (XRD). It was found that after annealing the blended elemental powder elemental the blended annealing that after It was found (XRD). 1150 even at up to 500 Koichiro Inoue elemental form in addition to the Ti5Si3 and TiAl phases present in phases present and TiAl to the Ti5Si3 addition form in elemental and Al Ti, Si MA, TiH1.924, hours of after 15 However the system. fused XRD which resulted in wide, in an amorphous phase were present around 425 of Ti5-Si3 was observed peaks. Formation up to 660 after heating ther formation of Ti5Si3 phases. Some amount of titanium was still Some amount of titanium of Ti5Si3 phases. ther formation at 1150 the system. After annealing present in were present in the alloy and were stable phases, Ti5Si3 and TiAl or heating of the alloy. during subsequent cooling 9:20 AM Prop- Effect on Resistivity and Tensile of Cr Substituted for Fe erties of Ti-Fe-Cr Alloys

WEDNESDAY AM 143 Herenilton PaulinoOliveira containing Ce,Pr, andsomeoftheNd.TheNd remaininginthe loaded organicundergoes selectivestripping,yielding anaqueousstream extracted. LaandresidualCeare recoveredfromtheraffinate.The Nd andafractionoftheCeappropriate forthefinalapplicationis solvent extractionwithcationexchange orsolvatingextractants.Pr, higher rareearths,aqueousfeedcontaining lightrareearthsundergoes solvent extractionconfigurationallows this.AfterseparatingSmand mixed rareearthsoftheappropriate compositiondirectly. A new nets containingPr,Nd,andsomeCe,itwouldbepreferabletoproduce elements orcompounds.Formanufacturinghighenergy-productmag- Conventionalrareearthpurificationprocessesproducepure,single One ResearchCircle,BuildingK-1,Niskayuna,NY12309USA ley, CA94720-1760 USA; Berkeley, Dept.ofMatls.Sci.andEng.,551EvansHall#1760,Berke- C. Shei Energy-Product Magnets Direct ProductionofMixed,RareEarthOxideFeedforHigh 10:30 AM 10:00 AMBreak 1997/05779-1. were notverified.ThisworkwassupportedbyFAPESP undergrant structural changesofxenotimegrainsduringthechlorinationreaction (YOCl, confirmedbypowderXRD).Moreover,significantmicro- shrinking-unreacted-core modelwithaformationofproductlayer were usedinthisstudy. Theresultsshowthatthereactionfollows UV/Vis transmissionspectroscopy, FTIR,thermalanalysistechniques tem tocontrolthegasesfluxes.PowderX-raydiffraction,SEM,EDX, for theessaysincludedhorizontallyelectrictubularfurnaceandasys- mechanistic studieshavebeenperformed.Theexperimentalapparatus rachloride attemperaturesfrom873Kto1173K,andkinetic investigated thedecompositionofxenotime(YPO costs andmakingtheprocesslesscomplicated.Inthiscontext,we thionyl chlorideandcarbontetrachloride,reducingtheoperations nating agents(chlorination),likegaseouschlorine,hydrogenchloride, thanides chloridesoroxychloridesisreactingthemineralwithchlori- cesses, involveseveraloperations.Anotherpossibilitytoobtainlan- ods ofdecompositiontheseminerals,usuallyalkalineoracidpro- have beendeservingattentionforrareearthindustry. Traditional meth- Amongtherareearthminerals,fluorides,phosphatesandoxides Bandeirantes 3900,RibeirãoPreto,SãoPaulo14040-901Brazil Faculdade deFilosofiaCiênciaseLetrasRibeirãoPreto,Av. netic andMicrostructuralStudies Decomposition ofXenotimewithCarbonTetrachloride: Ki- 9:30 AM recoveries upto90%werereadilyobtained. extraction ofrareearthsfromthepreconcentrate.Rareearthleach Sulphuric acidbakingandsubsequentwaterleachingwereusedforthe carried outbyapplyingvariousphysicalconcentrationmethods. by cyclones.Thebeneficiationoffluorideandbaritemineralswas recovery of77.5%waspreparedbyattritionscrubbinganddesliming other products.Arareearthpreconcentratewith23.5%REOa able fortheproductionofmarketablebastnaesiteconcentrateand tional concentrationandhydrometallurgicalmethodswerenotsuit- earth elementsareenrichedconsiderablyinsub-sievesizes.Thetradi- particles orisintimatelyassociatedwiththeseminerals.Therare mineral occurseitherascementmaterialbetweenfluorideandbarite calcite (2.8%)andminoramountsofthorium,etc.Thebastnaesite constituents oftheorearecalciumfluoride(52.5%),barite(25.4%), concentration of3.42totalREOwasusedinthisstudy. Theother key, withanestimatedoredepositof1milliontons,andaverage Abastnaesitetyperareearthmineral,locatedinBeylikahir,Tur- and Matls.Eng.,Ankara,Turkey Yavuz Topkaya Recovery ofRareEarthsfromaBastnaesitePreconcentrate 9:00 AM work, andCarlAuer’s discoveriesthatledtotheindustryareoutlined. first rareearthindustry. DetailsoftheSwedishcontribution,Bunsen’s of themineralstocontinuehisresearch.Fewyearslaterhestarted gadolinite. OnhisreturntoVienna, CarlAuertookwithhimsamples 2 ; DingShanBao 1 ; 1 Middle EastTechnical University, Dept.ofMetallu. 3 ; NiDeZhen : 2 GE CorporateResearchandDevelopment, Fiona M.Doyle 1 ; 1 São PauloUniversity, Chem.Dept., : EvandroBatistaAugusto 3 ; 1 University ofCaliforniaat 1 ; MarkG.Benz 4 ) usingcarbontet- 2 ; Juliana 1 ; : Keller Cell DesignfortheElectrolysisofNeodymiumOxide 11:30 AM ping circuitinanindustrialsolventextractionplant. acid. Thestudyalsoaddressesthefeasibilityofaprecipitationstrip- and MEHEHPsolutionsusingsaturatedaqueousofoxalic teristics oftheheavylanthanides,particularlylutetium,fromD2EHPA lanthanides. Thisstudydescribestheprecipitationstrippingcharac- onstrated thefeasibilityofoxalateprecipitationstrippingforlight thanide ionsfromD2EHPA andMEHEHP. Previousstudieshavedem- ping byprecipitationhasbeeninvestigatedfortheremovaloflan- cesses, therebygreatlyreducingthequantitiesofwasteproduced.Strip- tential toreducetheacidconsumptioninsolventextractionpro- volumes ofneutralizedacidwaste.Precipitationstrippinghasthepo- thanides areprecipitatedastheoxalates.Thisprocessgenerateslarge aqueous lanthanidesolutionsaresubsequentlyneutralizedandthelan- mono-2-ethylhexyl-(2-ethylhexyl)-phosphonic acid(MEHEHP).The extractant, typicallydi-(2-ethylhexyl)phosphoricacid(D2EHPA)or trated mineralacidstoremovethelanthanideionsfromorganic thanides. Manyindustrialprocessesrequirelargequantitiesofconcen- Solventextractioniswidelyusedforthepurificationoflan- Buehler Hall,Knoxville,TN37996USA cipitation StrippingfortheHeavyLanthanides Waste ReductioninSolventExtractionProcesses UtilizingPre- 11:00 AM sponse toproductspecificationsandmarketeconomics. stream canbeadjustedbyoperatingparameters,allowingflexiblere- The proportionsofNdreportingtothemixedfeedandpure partially strippedorganiccanberecoveredasahighpurityproduct. slurries andsurfacefilmsonsilicasiliconnitrides. are usedtoelucidatetheinteractionbetweenceriaparticlesinCMP mobility ofceriaparticlesinthepresenceandabsencesilicateions, coupled withzetapotentialdataderivedfromtheelectrophoretic stability diagramsforthesystemsCe-H this materialisstilllittleunderstood.Inpresentation,aqueous ogy. Inspiteofthegrowinguseceriaslurries,polishingaction has beenextendedtoCMPapplicationsinmicroelectronicstechnol- (CMP) ofglassandsiliconnitridesurfaces.Recently, theuseofceria is animportantabrasivematerialforchemical-mechanicalpolishing Ceria(CeO USA University, Dept.ofMatls.Sci.&Eng.,UniversityPark,PA 16802 Considerations Mechanical Polishing(CMP):SolutionandSurfaceChemical Cerium OxideParticlesinAqueousSlurriesforChemical 12:00 PM ing agitationinthecathodearealow. keep theelectrolytevigorouslyagitatedinanodearea,whilekeep- C2F6. Water modelstudiessuggestedspecialcelldesignfeaturesto yields ofneodymium-ironalloy, withouttheemissionofanyCF4or experiments whichextendedover96hoursandproducedacceptable gases. Relateddifficultieshavebeencontrolledsuccessfullyin100-A product reoxidation,sludgeformationandemissionofperfluorocarbon there arealsosignificantdifferences,suchasincreasedtendenciesto similar tothatofthecommercialelectrolysisaluminumoxide,but high-quality neodymiummetalandalloys.Theprocesschemistryis Theelectrolysisofneodymiumoxideisaneffectivewaytoproduce USA George K.Schweitzer 1 ; 1 EMEC Consultants,4221RoundtopRd.,Export,PA 15632 2 ), intheformofdispersedparticlesaqueoussolution, : K. Osseo-Asare 1 ; 1 University ofTennessee, Dept.ofChem.,552 1 ; P. Suphantharida 2 O, Si-H : 2 O, andSi-N-H Peter M.Smith 1 ; 1 Penn State : Rudolf 2 O, 1 ;

WEDNESDAY AM 144 C ° K, ; S. 1 ∆ Alloy De- 1 ; 1 : D. Padhi US Army Research 1 Johns Hopkins Uni- 2 Case Western Reserve Case Western ; 1 2 ; 1 Robert G. O’Donnell : C ; Wen-Sheng Chu ; Wen-Sheng Cessna Aircraft, Wichita, KS USA 3 1 ° ° ° ° ° John J. Lewandowski University of Michigan, Dept. of Matls. Sci. and of Matls. Dept. of Michigan, University ; 2 3 C to 300 ° ° ° ° ° C, is investigated. The four principal fracture mecha- Paul J. Huang ° : ; W. Zinsser ; W. 1 C on the fracture toughness have been determined on both Defense Evaluation and Research Agency, Sunbury on Thames, Sunbury Agency, and Research Evaluation Defense ° 3 C to 300 ° Solv’yev Private Bag 33, Clayton velopment Group, CSIRO Manu. and Sci. Tech., 3169 Australia Sth MDC, Victoria Liquid phase sintered W-Ni-Fe alloys comprise a semicontiguous, spheroidal, tungsten rich phase surrounded by a Ni-Fe rich matrix phase. In this work, the fracture behaviour of a 95wt%W 3.5wt%Ni deformed in tension at temperatures in the range 1.5wt%Fe alloy, 100 nisms within this alloy are: (i) intergranular fracture between tungsten University, Dept. of Matls. Sci. and Eng., The Case School of Eng., University, Cleveland, OH 44106 USA; The fracture toughness and fatigue crack growth behavior of Nb5Si3/ Nb composites have been determined over a range of test temperatures and conditions. The effects of changes in test temperature from 196 Laboratory, Matls. and Manufact. Direct., 2230 Tenth St., WPAFB, Tenth Direct., 2230 Manufact. and Matls. Laboratory, USA; OH 45433-781 48109 Arbor, MI Bldg., Ann H.H. Dow St., 2026 2300 Hayward Eng., USA; UK Middx TW167LN often titanium matrix composites SiC fibers used in Continuous This less than 5 mm in thickness. carbon coating of have an outer location for common initiation been identified as the coating has A series of to the fiber axis. in tension transverse composite failure deposition using chemical vapor coatings were deposited three carbon monofilament temperature. The microstruc- while varying the SiC scanning examined using optical microscopy, tures of these fibers were Trans- and transmission electron microscopy. electron microscopy, the composite samples revealed that verse tensile tests on single-fiber not debonding of the fiber from the matrix was stress required to cause by deposition temperature. Adhesion experi- significantly affected in bond strength of the SiC-C interface with ments showed an increase in deposition temperature correlates with temperature. The increase texturing of the carbon coatings. In trans- increased crystallographic coating with the lowest SiC-C interface verse tension, the carbon interface, and the coatings with more highly strength failed at this within the coating. textured carbon failed 9:40 AM Aluminum Metal Matrix Evaluation of Various Tribological Composites & Matls. Rsch. Direct., AMSRL-WM-MC, Ab- Weapons Laboratory, erdeen Proving Ground, MD 21005-5069 USA; USA 3400 N. Charles St., Baltimore, MD 21218 versity, hurdles as it seeks to The military is currently facing substantial reduce weight and increase performance of its improve fuel economy, will be required to ground vehicles. Advanced technology and materials of potential engine meet these challenges. In particular, a number issues can be addressed applications where wear and weight are critical composites (Al MMC’s with the introduction of aluminum metal matrix with ceramic particu- Aluminum metal matrix composites reinforced temperature capability lates have higher wear resistance and higher there is limited wear than monolithic aluminum alloys. Unfortunately tests, and other mechani- data on these new materials. Block-on-Ring been made on various cal and thermal properties measurements have A359/SiCp/10%, (i.e. 6061/SiCw/20%, 2014/SiCp/15%, Al MMC’s alloys (i.e. 6061 and 2014/Al2O3p/15%), and monolithic aluminum of wear properties 2014). The scope of work is to develop a database monolithic alloys to assist future system designs and on Al MMC’s where wear resistance is a critical factor. 10:00 AM Fracture and Fatigue of Nb5Si3/Nb Composites to 500 binary Nb-Si alloys as well as multi-component Nb-Si alloys. In addition, the effects of changes in R-ratio and test temperature on the fatigue crack growth behavior have been determined. Quantitative fractography has been utilized to relate the effects of changes in R-ratio and test temperature on the fatigue crack growth rate. 10:20 AM Break 10:30 AM of a WNiFe Alloy in the Tempera- Deformation and Fracture ture Range—100 ; 2 Jenn-Ming : State Key Labora- 2 Air Force Research 1 ; Dr. Ronald Gibala ; Dr. ; 1 3 Arizona State Univer- 1 ; 1 University of California, Matls. 1 ; 2 Dr. Kevin L. Kendig Dr. John J. Lewandowski, Case Western John J. Lewandowski,

Nikhilesh Chawla Room: Bayou A Convention Center Location: Opryland ; Dr. Robert A. Shatwell ; Dr. : 1 ; Z. G. Wang 1 Daniel B. Miracle, US Air Force, Matls. and Daniel B. Miracle, US Joint ASM-MSCTS/TMS-SMD Composites Joint ASM-MSCTS/TMS-SMD ; Nanlin L. Han 1 Dr. Daniel B. Miracle Dr. Sci. and Eng., Los Angeles, CA 90095-1595 USA; tory of Fatigue and Fracture for Materials, Instit. of Met. Rsch., Chi- PRC Rd., Shenyang 110015 nese Acad. of Sci., 72 Wenhua The low-cycle fatigue lives and cyclic stress response characteristics of SiC-particulate reinforced aluminum composites with different particulate volume fraction have been investigated at room and elevated temperature. The specimens were cyclically deformed with fully-reversed loading under plastic-strain amplitudes. The dislocation substructure developed during cyclic deformation was examined by TEM. The results show that the unreinforced aluminum exhibited initial cyclic hardening, cyclic stability and secondary hardening at room temperature and cyclic softening elevated temperature, while the composites showed gradual softening over most of the fatigue life both at room and elevated temperature. The differences in dislocation substructure obtained from processing and its developments under cyclic strain loading were considered to give rise to the observed phenomena. 9:20 AM Microstructural and Mechanical Characterization of Carbon Coatings on SiC Fibers: sity, Dept. of Chem., Bio, and Matls. Eng., Tempe, AZ 85287-6006 Dept. of Chem., Bio, and Matls. Eng., Tempe, sity, USA several advantages over Metal matrix composites (MMCs) offer mechanical proper- conventional monolithic alloys. The enhanced modulus particles into a ties, which result from incorporation of high This talk will metallic matrix, are of interest for many applications. behavior of particulate provide a broad overview of the mechanical emphasis on SiC particle reinforced metal matrix composites, with an in these materials stems reinforced Al alloys. In general, strengthening strengthening (direct from a combination of classical composite and deformation strengthening) and changes in matrix microstructure from the presence of the characteristics (indirect effects) which arise volume fraction and reinforcement. The influence of reinforcement will be described. size on the mechanical behavior of the composites precipitate size, spacing, The effects of matrix microstructure (e.g., of the composites, as and distribution) on the mechanical response will be discussed. well as mechanical behavior at elevated temperatures 9:00 AM Particulate Reinforced Plastic Strain-Controlled Fatigue of SiC Al Composites at Room and Elevated Temperature 8:30 AM Invited Metal Matrix Com- Mechanical Behavior of Particle Reinforced posites-An Overview Yang Sponsored by: Sponsored Research and Development Efforts on Efforts and Development Research Mechanical Matrix Composites: Metal of MMCs Behavior Committee Leaders ; Young Committee Organizers: Program AM Wednesday Reserve University, Department of Materials Science and Department of Materials Science Reserve University, H. Hunt, OH 44106 USA; Warren Engineering, Cleveland, 15668 Group Inc., Murrysville, PA Aluminum Consultants USA March 15, 2000 Session Chairs: USA; Carl Patterson AFB, OH 45433 Mfg. Direct., Wright Dept. Mech. Eng., University, Boehlert, Johns Hopkins Baltimore, MD 21218 USA

WEDNESDAY AM 145 which suppressdamage formationincomposites and thusallowthe Hydrostaticextrusion representsamethodofproducing stressstates 3 L8S4L7 Canada; University, Matls.Sci.andEng.,1280MainSt.W., Hamilton,Ontario posites Some AspectsofHydrostaticExtrusion ofMetalMatrixCom- 11:30 AM cess. metric arrangementwasfoundtostronglyinfluencethedamagepro- decohesion. Atagivenvolumefractionofsapphirefibres,thegeo- age occursinthissystemeitherbyfibercrackingorinterfacial distribution wasexamined.Experimentsshowedthatextensivedam- calculations, theeffectofdamagedfibersonlocalstressandstrain element methodcalculationswereconductedusingLS-DYNA.Inthese monitored duringdeformation.Inadditiontotheexperiments,finite sion perpendiculartothefiberaxisandpatternofdamagewas by graphitespacers.Theresultingcompositeswereloadedincompres- and geometricarrangementofthefiberswasmaintainedduringcasting sapphire fiberswiththeliquidaluminumalloy. Thevolumefraction diameter). Thecompositewaspreparedbyinfiltratinganarrayof fabricated fromAA6061andsapphirefibers(aluminafibers,1mmin arrangement ofthereinforcingphase.Amodelcompositesystemwas process wasexaminedasafunctionofthespacingandgeometric accumulation ofdamageinamodeltwo-phasematerial.The Thegoalofthisworkwastosystematicallystudytheinitiationand Stores Rd.,Vancouver, BCV6T1Z4Canada 1 Al2O3 ModelComposites Experiments andNumericalCalculationsonDamageinAl/ 11:10 AM 200-300 MPa. particles/area totheSunmodelcalculateaninterfacialstrengthof maximum valueof~40%atfracture,and3)numberdecohered tion ofdecoheredparticlestotheWhiteheadandClinemodelupa Semiatin modeluptoamaximumvalueof1-2%atfracture,2)frac- models asfollows:1)areafractionofvoidstotheSeetharamanand at theinterface.Thedamagemeasurementswerefittedtoexisting nism isfailurethrougha20-40nmthickamorphousSi-Mg-Al-Olayer 2 grainwidthsadjacenttotheparticles,anddecohesionmecha- near-interface regionrevealedthatplasticstrainisconcentratedin1- microscopy (FIB).Transmissionelectron(TEM)ofthe were madeonsamplessectionedandimagedbyfocusedionbeam and 3)fractionofdecoheredparticles.Thelatter2measurements 1) density, 2)areafractionofvoidsresultingfrominterfacedecohesion during tensiletestingtothepointoffracturewasstudiedbymeasuring independent oftheeffectsparticlecracking.Damageevolution lowed theeffectsofinterfacestructureanddecohesiontobestudied late waspreparedbypowderprocessingandhotextrusion.Thisal- AnMCCofAl2080reinforcedwith20vol.%3umSiCparticu- Matls. andMetallu.Eng.,Kingston,OntarioK7L4N6Canada Robert DavidEvans formation ofanAl2080/20vol.%SiCMetalMatrixComposite Damage EvolutionbyInterfaceDecohesionduringTensile De- 10:50 AM final rupturemechanisminthesealloysisalsodiscussed. the specimen.Theroleoftheseinternalcracksindetermining straining priortofinalruptureresultsinthepresenceofcrackswithin cleavage. Intergranularfracturebetweentungstenspheroidsduring tion temperatureforthisphase,fractureisprimarilythroughtungsten sented inthefracturesurfacewhilstaboveductiletobrittletransi- ture forthetungstenphase,allfracturemechanismsarewellrepre- stress ofeachphase.Belowtheductiletobrittletransitiontempera- and howthesearerelatedtothetemperaturedependenceofflow terms oftherelativestrengthsindividualfracturemechanisms, mined tovarywithtesttemperature.Thisvariationisexplainedin the fracturesurfacefromeachofthesemechanismsisdeter- transgranular fractureofthetungstenspheroids.Thecontributionto the matrixmaterial,(iii)ruptureofmaterialand(iv) spheroids, (ii)interfacialfracturebetweenthetungstenspheroidsand University ofCalifornia,Matls.Dept., SantaBarbara,CAUSA University ofBritishColumbia,Dept.Met.andMatls.Eng.,6350 : D.Lahaie 2 University ofQuebec,Chicoutimi, Quebec,Canada; 2 ; 1 ; J. D.Embury James DouglasBoyd : Partha Ganguly 1 ; FrancisW. Zok 1 1 ; ; Warren JamesPoole 1 Queen’s University, 3 ; 1 McMaster 1 ; : Eng., Cleveland,OH44106USA Case Western ReserveUniversity, Dept.ofMatls.Sci.and Group, Murrysville,PA 15668USA;JohnJ.Lewandowski, Session Chairs: March 15,2000 Wednesday AM USA Aluminum ConsultantsGroupInc.,Murrysville,PA 15668 Engineering, Cleveland,OH44106USA;Warren H.Hunt, Reserve University, DepartmentofMaterialsScienceand Program Organizers: Committee; Young LeadersCommittee Sponsored by: Session onMMCs Metal MatrixComposites:Poster Research andDevelopmentEffortson Box Luncheonticketsrequired. MMC SymposiumPosterSessionandLuncheon 12:00 PM 11:50 AMClosingRemarks and AlbasedMMC’s. be consideredintermsofexperimentaldatabothforCu-Wcomposites extrusion andtheirrelationtodamageaccumulation.Theresultswill paper willdealwithanalysisofthelocalstressstatesinhydrostatic attainment ofsignificantplasticstrainsduringformingprocesses.This optical microscope, SEMandelectronmicroprobe, andmicroimage the rangeof1-10 with 25wt.%SiCwasobtained.The particlesizeofSiCformedwasin silicon carbidecontentinthecomposite. TheAl-Sialloycomposite liquid contactmethodandtemperature havesignificanteffectonthe 1150 posites usingmethanewascarried out inthetemperaturerangeof950- Experimentalinvestigationonsynthesis ofAl-SialloyandSiCcom- Bevill Bldg.,P.O. Box870202,Tuscaloosa, AL35487USA Wu In-Situ SynthesisofAl-SiAlloyandSiCComposite will beusedtoevaluatethephasespresentinmaterials. scanning calorimetry(DSC)andtransmissionelectronmicroscopy ties ofthesematerialswillbepresentedanddiscussed.Differential influence ofagingonthemicrostructure,hardness,andtensileproper- approach, toprovideimprovedstrength-toughnessrelationships.The and Al-Sc-Mg/15vol.%SiCcomposite,madebyapowdermetallurgy characteristics ofarelativelynewclassmaterials:Al-Sc-Mgalloy ments. Inthisstudy, attemptsarebeingmadetounderstandtheaging expansion (CTE)mismatchbetweenmatrixandceramicreinforce- hanced dislocationdensityresultingfromthecoefficientsofthermal aging behaviorascomparedtotheunreinforcedalloydueen- rial. Ithasbeenwelldocumentedthatthecompositesshowaccelerated posites withprecipitationhardenedaluminumalloysasamatrixmate- aging responseofdiscontinuouslyreinforcedaluminum(DRA)com- Considerableefforthasbeenmadeinthepasttounderstand Main St.,EastHartford,CT06108USA Superior St.,Chatsworth,CA91377USA; Base, Dayton,OH45433USA; and Manu.Direct.,223010thSt.Ste.1,Wright-PattersonAirForce Rd., Dayton,OH45432USA; Watson Awadh B.Pandey Aging CharacteristicsofAl-Sc-MgAlloyandItsComposite 1 ; RamanaG.Reddy ° C. Akineticmodelfortherateprocess wasdeveloped.Thegas- 4 ; 1 UES Inc.,Matls.andProcess.Div., 4401Dayton-Xenia Joint ASM-MSCTS/TMS-SMDComposites 1 ; DanielB.Miracle µ Warren H.Hunt,AluminumConsultants m. Reactionproducts werecharacterizedusing 1 ; Location: OprylandConventionCenter Room: BayouA 1 John J.Lewandowski,CaseWestern University ofAlabama,Metallu.Eng.,A129 2 Air ForceResearchLaboratory, Matls. 3 DWA AluminumComposites,21130 2 ; CoryA.Smith 4 Pratt &Whitney, 400 3 ; ThomasJ. : Banqiu :

WEDNESDAY AM 146 ; ; : 1 1 John J. U.S. Steel ; 2 3 ; J. Larose 1 ; C. W. Chen ; C. W. 1 ; Y. P. Hu P. ; Y. : S. Solv’yev 1 ; Paul T. Wang ; Paul T. Alcoa Technical Center, 100 Center, Alcoa Technical 3 3 Case Western Reserve University, Case Western 1 ; 1 Kali Mukherjee : ; Thomas J. Rodjom 2 Case Western Reserve University, Dept. of Matls. Sci. Reserve University, Case Western 1 ; Los Alamos National Laboratory, Los Alamos, NM 87545 Los Alamos, NM Los Alamos National Laboratory, 2 1 John J. Lewandowski ; 2 Michigan State University, Matls. Sci. & Mech., and Comp. Matls. Matls. Sci. & Mech., and Comp. Michigan State University, Lewandowski Research Center, Monroeville, PA USA; Monroeville, PA Research Center, Dept. of Matls. Sci. & Eng., The Case School of Eng., Cleveland, OH Dept. of Matls. Sci. & Eng., The Case School 44106 USA; USA behavior of Al-Be The fracture toughness and fatigue crack growth of test conditions. composites are being determined under a variety both notched and fatigue Fracture toughness is being determined on behavior is being precracked specimens, while fatigue crack growth of test conditions on the measured at different R-ratios. The effects behavior will be summa- fracture toughness and fatigue crack growth of the fracture rized in addition to both optical and SEM examination path and fracture surfaces. Processing Model For Densification and Flow Stress Evolution (DRA) Composites Discontinuously Reinforced Aluminum and Eng., Case School of Eng., Cleveland, OH 44106 USA; posed of 50~71vol% SiC particles were fabricated by ball milling and by ball milling fabricated were SiC particles of 50~71vol% posed of by an infiltration fabricated were SiCp/Al MMCs method. pressing cast- infiltration the pressure using particle preforms into SiC Al melt ex- of thermal coefficients and conductivities Thermal ing process. varying the were characterized with of SiCp/Al MMCs pansion (CTE) and po- content of inorganic binder of SiC particles, volume fraction analysis, re- thermomechanical laser flash method and rosity using to 120W/ from 177W/mK conductivity decreased Thermal spectively. increasing the to 6ppm/K with decreased from 10ppm/K mK and CTE 50vol% to in SiCp/Al MMC from of SiC particles volume fraction coefficients of thermal expansion were in good 71vol%. The measured coefficients of thermal expansion based agreement with the calculated mode. on Turner’s by Laminated Metal-Matrix Composites Direct Deposition of Laser Cladding Process 1 MI Laser Process. Lab., East Lansing, High Energy and Struct. Ctr., 48824 USA has been employed to directly deposit Laser cladding technique composites (LMMCs). By using optimized laminated metal matrix associated with 3-D geometric components, processing parameters steel, and CPM10V tool steel layer compo- alternate 304L stainless prototypes on steel sub- nents have been successfully produced. The metallurgically sound. strates are found to be relatively smooth and are free of pores Optical micrographs displayed that LMMC samples with the substrate, and cracks, and have a good metallurgical bonding discrete and serrated but with a low dilution. Laminated layers have compositions, and me- interface to maintain both original chemical The hardness layer. chanical and physical properties for each cladding tool steel CPM10V is of LMMC layers of stainless steel 304L and Processing parameters, and respectively. about 300 Hv and 750 Hv, in detail. properties associated with this study will be discussed Fracture and Fatigue of Al-Be Composites R. Castro Erik J. Hilinski USA 15069-0001 PA Alcoa Ctr., Dr., Tech. The current processing technology in the realm of discontinuously reinforced aluminum (DRA) materials generally employs a two step forming sequence whereby a powder compact (powder-void aggregate) is consolidated to full density and then extruded or forged into a desired component shape. In order to combine the consolidation and shaping operation into one processing step, an analytical description of the thermomechanical behavior of porous materials that provides an understanding of the key densification mechanisms and processes in powder consolidation is desired. A constitutive model of porous mate- imbedded within a finite element rial densification and plastic flow, model, would prove to be a useful tool in aiding the design of both die and preform; a key element in consolidating and shaping porous material into void-free products with one operation. This poster presents the efforts to develop the densification and flow stress evolution processing model. A porous yield criterion based on the Gurson micromechanical model, as modified by Tvergarrd, Richmond and is used to predict the densification response of the and Wang, Smelser, powder processed composite material. Ex-situ density measurements, The 1 Carlos ; Soon ; 1 1 ; 1 Guangbin : Efrain Carreño- : Ecole Polytechnique Hyo Soo Lee 1 : ; 1 : Rafael Auras ; Glenn S. Daehn 1 C and the results show that the five C and the results show ° ; Robert Schaller 2 University of Misiones, Faculty of Sci., Azara of Misiones, Faculty of University ; Robert H. Wagoner 1 1 ; 1 Korea Advanced Institute of Science and Technology, 1 Hoeganaes Corporation, Rsch. and Dev., 1001 Taylors 1001 Hoeganaes Corporation, Rsch. and Dev., 2 ; 1 ; Nikhilesh Chawla 1 ; Weidong Wu ; Weidong 1 Matls. Sci. and Eng., 373-1 Kusung-dong, Yusung-gu, Taejon 305-701 Taejon Matls. Sci. and Eng., 373-1 Kusung-dong, Yusung-gu, Korea Fabrication process and thermal properties of high volume fraction ranged 50~71vol% SiCp/Al metal matrix composites (MMCs) for electronic packaging applications have been investigated. Preforms com- Ohio State University, Matls. Sci. and Eng., 477 Watts Hall, 2041 Matls. Sci. and Eng., 477 Watts Ohio State University, College Rd., Columbus, OH 43210 USA under cyclic pressure has been Powder consolidation of MMC’s densities in mixed previously shown to produce significantly higher powders when the two powders have dissimilar compressibilities. Smaller effects when the reinforcement content is small, and large enhance- ments are possible at high ceramic loadings. This is a complex process that involves many mechanisms including pressure-change induced In order to powder rearrangement and frictional sliding. plasticity, remove the effects of powder rearrangement and consider the defor- steel closely-packed macro-sized aluminum and mation behavior only, rods studied in cyclic compaction. The finite element code, ABAQUS was employed to simulate the densification behavior under static and cyclic pressure. From simulations it is shown friction between particles has great effect on densification under cyclic pressure. Data obtained from the simpler arranged rods are compared with powder consolida- tions and both are compared to simulations. These are discussed in the fric- context of determining the relative contributions of plasticity, tion and rearrangement in powder consolidation. of High Volume and Thermal Properties Fabrication Process Fraction SiCp/Al Metal Matrix Composites Hyung Hong Fédérale de Lausanne, Institut. de Génie Atomique, Lausanne CH-1015 Fédérale de Lausanne, Institut. de Génie Atomique, Switzerland; Jiang Ln., Cinnaminson, NJ 08077 USA Al/SiCp composites was The thermo-mechanical behavior of 2080 The thermal fatigue behav- investigated by mechanical spectroscopy. by mechanical loss and ior, between 100 K and 400 K, was studied mechanical loss dynamic shear modulus measurements. A transient 150 K, that originates maximum was observed during cooling near the differential thermal from relaxation of thermal stresses due to Decreasing particle size expansion between matrix and reinforcement. and in improved di- resulted in a decrease in the damping maximum by keeping the Finally, mensional stability during thermal cycling. matrix microstructure volume fraction and particle size constant, the and dislocation distribu- was varied to study the effect of precipitate The effect of tion on stress relaxation around the reinforcement. the microplasticity near inclusion size and matrix microstructure on stresses will be dis- the interfaces induced by thermal and mechanical cussed. of the Consolida- Experimental and Numerical Examination Cycling tion of Composite Powders in Pressure Enirique Schvezov Morelli 1552, Posadas, Misiones 3300 Argentina 1552, Posadas, their micro- were cast and alloys and composites Zinc-Aluminum determined wear properties were stability and structure, dimensional Copper and containing Silicon, Five different alloys and analyzed. were employed. The cast alloys were tested Silicon Carbide particles at 165 for a period of 1000 hr the were dimensional stable during different alloys and composites were performed using a pin-on-disc appara- whole test. The wear test 8 conditions. The charges used were 5 and tus under dry and lubricated The rpm (2m/s) and the test time was 1 hr. Kg, the velocity was 250 that under dry conditions there was considerable wear test results show in the non-reinforced alloys. In addition, lost of material, particularly presented substantial local plastic deforma- the non reinforced alloys from the disc to the sample. tion and transfer of elements Characterization of 2080 Al/SiCp Com- Thermo-Mechanical Technique Spectroscopy posites by Mechanical analyzer. Calculated SiC formation rate agrees well with experimental well with rate agrees SiC formation Calculated analyzer. results. of Stability and Dimensional Microstructure Behaviour, Wear Alloys As’Cast Zinc-Aluminum/SiC(MMC)

WEDNESDAY AM 147 Hahn Choo behavior between thelayersundermixedloading conditions.This the observedfracturebehavioris associated withtheinterfacialfailure The detailedfractographicstudies andnumericalanalysisindicatethat diminished withincreasingmode-II componentforlargermodemixities. to presenceofrelativelyductile6061Al layers,thisimprovementwas increase inthefracturetoughnessvalue underpuremode-Iloading,due respect toorientationofthelayers. Although,therewasasignificant tests, initialfatiguecrackswereinthecrackdividerorientation in ticulate reinforcedcompositewasinvestigated.Duringthefracture posite consistingof6061Alalloylayersand2014Al-20vol%SiCpar- Inthisstudy, themixed-modefracturebehavioroflaminatedcom- Ames Lab.,Ames,IA50011USA Composites Mixed-Mode FractureBehaviorofLaminatedMetal-Matrix 7405-Eng-82. Department ofEnergybyIowaStateUniversityundercontract W- the laminatetheory. This workwasperformedfortheUnitedStates constituent phases.Thisbehaviorisexplainedwithamodelbased on of thelaminatedcompositeweremuchshorterthanthoseseenfor its of delaminationbetweenthelayers,observedcreeprupturetimes reinforced compositelayerswasinvestigated.Inspiteoftheabsence consisting of6061Alalloylayersand2014Al-20vol%SiCparticulate Inthisstudy, thecreepbehaviorat250 Lab., Metallu.andCer., Ames,IA50011 USA Matrix Composites Creep DeformationandRuptureBehaviorofLaminatedMetal of materials. neutron diffractionasatechniquethatisuniqueinstudyingthisclass ture. Theseresultsarepresentedinordertodemonstratetheuseof 6Al-4V matrixmaterialwasalsodeterminedasafunctionoftempera- ation ofstressesinboththealpha( stress relaxationeffectsinthefiberandmatrix.Inaddition,relax- from 20-1050°CwereconductedonaSiC/Ti-6Al-4VMMCtostudy tungsten/Kanthal MMC’s. Hightemperaturemeasurementsranging at thefibermatrixinterfaceusingsimplemicro-mechanicsin mine theeffectofvaryingV percent offibersbyvolume(V determined intungsten/KanthalMMC’s containing10,20,30and70 bide (SCS-6)reinforcedtitaniumalloy. Residualstrains/stresseswere posites (MMC’s): tungstenfiberreinforcedKanthal,andsiliconcar- strain andstressintwocontinuousfiberreinforcedmetalmatrixcom- Pulsedneutrondiffractionwasusedtodetermineresidualelastic sity, Dept.ofMech.Eng.,Medford, MA02155USA Ctr., Lansce12,H805,LosAlamos,NM87544 USA; Alamos, NM87545USA; tional Laboratory, Matls.Sci.andTech., MST-8,LANSCE12,Los Reinforced MetalMatrixComposites ume FractionandTemperature onResidualStresses inFiber Neutron DiffractionStudyontheEffectofReinforcement Vol- ent materialssystems,includingcomposites. experimental observationsthathavebeenmadeonavarietyofdiffer- has recentlybeencompleted.Thispresentationwillsummarizethe and deformationprocessingofbothmonolithicmetalscomposites Areviewoftheeffectshighpressureonmechanicalbehavior School ofEng.,Cleveland,OH44106USA Western ReserveUniversity, Dept.ofMatls.Sci.&Eng.,TheCase posite Materials Pressure EffectsonFlowandFractureofMonolithicCom- tion descriptionofthematerial. into considerationinordertodevelopanaccurateflowstressevolu- that theagingcharacteristicsofmatrixmaterialmustbetaken internal statevariabletheoryhasbeenunsuccessfultodate.Itappears the DRAmaterialduringuniaxialcompressiontestingusingsingle are presented.Anattemptatpredictingtheflowstressevolutionof of themonolithicandcompositematerialsusedinthisinvestigation evolution inopendieuniaxialcompressionspecimens.Yield surfaces variation ofporosityandhavealsobeenusedtodetermine via thearchimedeandensitometrymethod,havebeenusedtotrack 2 : ; MarkA.M.Bourke S. B.Biner : P. Lowhaphandu : S. B.Biner 1 ; 2 f 1 oftungstenfibersontheresidualstresses Los AlamosNationalLaboratory, Lujan Iowa StateUniversity, Metallu.andCer., f ). Thefocusofthisstudywastodeter- 1 α ; AnilK.Saigal ) andbeta( 1 ; 1 ; 1 John J.Lewandowski Iowa StateUniversity, Ames : ° C oflaminatedcomposite Partha Rangaswamy β ) phasesofthe 3 ; 1 Los AlamosNa- 3 Tufts Univer- 1 ; α - 1 β Case Ti- 1 ; tion UsingModelGeometries Experimental andNumericalExaminationofStaticCompac- tion andacousticstreaming. sonic treatmentisbelievedtobethecombinedeffectsofcavita- experiment andnumericalsimulation.Themechanismoftheultra- effective rangeofhighintensityultrasonictreatmentisstudiedby on thevolumefractionratherthansizeofreinforcement.The with goodbondingmatrixandthemechanicalpropertiesdepend are studied.Theresultsshowthatparticlesdispersehomogeneously used is0.5micrometer. Themicrostructureandmechanicalproperties Al compositesinthispaper. Theminimumdiameterofreinforcement intensity ultrasonictreatmenthasbeenusedtofabricateAl2O3p/Zn- liquid metalbecauseofthepoorwettabilityparticles.High usually verydifficulttodisperseceramicparticleshomogeneouslyin the lowcostliquid-metalprocessmaybeutilizedmostly. However, itis AlthoughmanytechniqueshavebeenusedforproducingMMC’s, Daehn sure Cycling Explicit FEMSimulationofPowderConsolidationUnderPres- simulation havebeenlimited. have beendone,butcarefulcomparisonsbetweenexperimentand be giventocomposite-powdercompaction,anareamanyexperiments phology, sizedistributionandsurfacecondition.Particularfocuswill will attempttocalibratetheeffectsofparticlerearrangement,mor- deformed shapesofthealuminum.Basedonthiswork,ourfuturework curves fromsimulationandexperimentsareverycloseasthe for inthemodelingofpowderconsolidation.Thedensity-pressure sure causesproducessignificantspringbackthatshouldbeaccounted tion, butshowsnoeffectinpurematerialcompaction.Contactpres- ticle-interface frictionretardsthedensificationincompositecompac- that inclusionsinhibitedthedensificationduringcompaction.Par- of plasticdeformationevolutionuptofulldensity. Investigationshowed nating theeffectsofparticlerearrangementandrevealing and square-packingarrangementsofaluminumsteelrods,elimi- pressure-density curvesweremeasuredusingbothclosed-hexagonal effects andspringbackbehaviorduringcompactionejection.The ployed tosimulatethedensificationbehavior,inter-particlefriction steel andaluminumaswellpurerods.ABAQUSwasem- both close-packedandcubicarrayswithmixturesofhardened tem. Staticuniaxialdiecompactionwascarriedoutwithsetsofrodsin merically usingaluminumandsteelrodsasamodelplane-strainsys- uniaxial compactionwasinvestigatedbothexperimentallyandnu- Thedeformationbehaviorofmetalmatrixcompositesincold USA Sci. andEng.,477Watts Hall,2041 CollegeRd.,Columbus,OH43210 S. Daehn ment The Al2O3p/Zn-AlCompositesFabricatedbyUltrasonicTreat- Iowa StateUniversityundercontractW-7405-Eng-82. work wasperformedfortheUnitedStatesDepartmentofEnergyby leads toslightly decreased consolidationdensityfor agivenpressure, clic loading.Inthe rangeof0to0.3,increasing friction coefficient monotonic loadingconditions,while largerdiscrepanciesexistforcy- There isgoodagreementbetween simulationsandexperimentsunder ties, andloadingconditionshave beeninvestigatedsystematically. combinations ofmaterials,particle arrangement,interfacialproper- compaction canalsobehandled withoutextradifficulties. Various Pentium workstationinafewdays. Particlere-arrangementduring of over50,000degreesfreedomandtensloadingcycleson a Explicit FEM(finiteelementmodeling)wasusedtosimulatesystems ramic content,improvedhomogeneityandbetternetshapeprecision. processing canproducecompositeswithhighervolume-fraction ce- ties thancanbeobtainedbynormalconsolidationprocedures.Such to consolidatecompositepowders(i.e.metal/ceramic)higherdensi- Pressurecyclinghasbeenshownexperimentallytobeaviablemethod OH 43210USA University, Dept.ofMatls.Sci.andEng.,2041CollegeRd., Columbus, Eng., 338RathboneHall,Manhattan,KS66506USA; PRC; Jiao Tong University, SchoolofMatls.Sci.&Eng.,Shanghai200030 : 2 2 Southeast University, Dept.ofMatls.Sci.&Eng.,NanjingPRC ; G.Jiang Wang Jun 1 ; RobertH.Wagoner : 2 1 ; X. J.Xin ; SunBaode 1 Kansas StateUniversity, Dept.ofMech.andNuclear 1 ; P. Jayaraman 1 : ; ShuGuangji 1 ; Weidong Wu 1 The OhioStateUniversity, Matls. 1 2 ; R.H.Wagoner ; ZhouYaohe 1 ; GuangbinJiang 2 The OhioState 1 ; 1 Shanghai 2 1 ; G.S. ; Glenn

WEDNESDAY AM 148 C ° ; J. 1 S. W. Banovic S. W. : Post-exposure character-

atm]. -4 Λ Lehigh University, Dept. of Matls. Sci. Lehigh University, 1 ; 1 Sudipta Seal, University of Central Sudipta Seal, University Room: Canal B Location: Opryland Convention Center atm, p(S2) = 10 V. H. Desai, University of Central Florida, V. Materials Processing and Manufacturing Materials Processing -25 Λ ; A. R. Marder 1 N. DuPont ization of the corrosion reaction products consisted of surface and cross-sectional microscopy in combination with energy dispersive spectroscopy and electron probe microanalysis. The corrosion behavior of weldable compositions of Fe-Al alloys in an oxidizing/sulfidizing atmosphere was found to be directly related to the aluminum content of For high aluminum compositions (above 7.5 wt% Al), pro- the alloy. tection was afforded due to the development of a thin, continuous gamma alumina scale that inhibited rapid degradation of the alloy. 8:30 AM Overlay Coatings for Use in Characterization of Fe-Al Weld Sulfidizing Environments High Temperature 18015 USA Bethlehem, PA and Eng., 5 E. Packer Ave., Iron-aluminum alloys are currently under investigation for use as corrosion protective weld overlay coatings in reducing environments. These materials are relatively inexpensive, do not exhibit macro- or microsegregation, and have better corrosion resistance compared to convention Ni-based and stainless steel-type compositions presently in use. However, their use is limited due to weldability issues and their lack of corrosion characterization in very aggressive environments. Therefore, the objective of this research was to examine the sulfidation behavior of weldable Fe-Al compositions in highly aggressive reducing atmospheres. The high temperature corrosion behavior in environments containing oxygen and sulfur was characterized by thermogravimetric techniques. As-solidified Fe-Al alloys, with 0-20 wt% Al, were isothermally held at temperatures between 500-700 pact loading pre-cracked three point bend specimens in a modified specimens point bend three pre-cracked pact loading load- force versus load-point measured The bar apparatus. Hopkinson required the energy estimate used to, (a) curves are displacement point of the interaction the and (b) understand initiation, crack for dynamic reinforce- with the ductile phase propagating crack tip dynamically DRA com- extrinsically toughened results indicate that the ments. The propagation. energy during crack significantly greater posites absorb volume is affected by the location, extrinsic toughening The level of mechanicalfraction and reinforce- of the ductile phase properties ments. in Materials Sci- Surface Engineering Properties ence I: Coating/Films Evaluation (PE)-I Sponsored by: Committee Division, Surface Engineering Program Organizers: Materials Processing and Analysis Florida, Advanced Aerospace Engineer- Center and Mechanical, Materials and B. Dahotre, Univer- ing, Orlando, FL 32816 USA; Narendra Space Institute, Center for Laser Applica- sity of Tennessee Mishra, tions, Tullahoma, TN 37388 USA; Brajendra for Extractive Colorado School of Mines, Kroll Institute Moore, Colo- Metals, Golden, CO 80401-1887 USA; John and rado School of Mines, Department of Metallurgy USA Materials Engineering, Golden, CO 80401 AM Wednesday March 15, 2000 Session Chairs: Orlando, FL 32816 USA; and Ana. Ctr., Matls. Process. Adv. Central Florida, Schl. of Optics and Ctr. University of A. Kar, for Rsch. and Edu., Orlando, FL 32816 USA for up to 100 hours in a reducing environment. Specially tailored gases maintained the partial pressure of oxygen and sulfur at each temperature [p(O2) = 10 ; 1 Al 3 Yu-Lin : ; Dr. Warren ; Dr. 3 ; Seung-Hyun Kim ; Seung-Hyun 1 Case Western Reserve Uni- Case Western 2 Hoeganaes Corporation, Rsch. 2 Yong-Suk Kim Yong-Suk : ; Prof. John J. Lewandowski 1 University of New Mexico, Dept. of Mech. 1 ; 2 Kookmin University, School of Metallu. and Matls. School of Metallu. and Kookmin University, 1 Case Western Reserve University; Dept. of Mech. and Reserve University; Case Western ; 1 1 ; Dr.V. Prakash ; Dr.V. ; 1 3 ; Nikhilesh Chawla 1 Consultants Group, 4530 William Penn Hwy, Murrysville, PA 15668 Murrysville, PA Penn Hwy, Consultants Group, 4530 William USA DRA composites have been processed to Extrinsically toughened enhance their damage tolerance. The dynamic compression behavior of the composites is examined by employing the split Hopkinson the com- The measured dynamic stress-strain response of pressure bar. posites is correlated with the macro- and micro- damage mechanisms inferred from post examination of the impacted specimens. The dynamic fracture characteristics of the composites are obtained by im- H. Hunt, Jr. Aero. Eng., Cleveland, OH 44106 USA; Dept. Mats. Sci. and Eng., Cleveland, OH 44106 USA; versity, Eng., Albuquerque, NM 87131 USA; and Dev., 1001 Taylors Ln., Cinnaminson, NJ 08077 USA Ln., Cinnaminson, NJ 08077 1001 Taylors and Dev., the mechanical Hardness tests are used extensively in quantifying between hardness properties of metallic materials. Good correlation for many alloys. As and tensile strength have been well documented interest from indus- metal matrix composites are generating increased traditional hardness testing may serve as a simple and useful means try, this study we attempt to of characterizing the composite strength. In between hardness develop a baseline understanding of the correlation matrix composites. and strength of discontinuously reinforced metal and sizes of silicon Aluminum alloys reinforced with various amounts in all compos- carbide particles were used. The matrix microstructure of heat treating and ites was kept relatively constant by a combination B scale hardness tests and the Rockwell rolling operations. Tensile composites with small tests were performed. It was found that for well with tensile reinforcement particles, the hardness value correlated particles, the hard- strength. For composites with larger reinforcement It is believed that the ness test overestimated the tensile strength. during extrusion and larger silicon carbide particles tend to be fractured overall load carrying tensile testing, which reduces the composite’s compres- In hardness tests the predominantly macroscopic capacity. sive load during indentation resulted in the particles being pushed and Thus, particle fracture during indentation was significant matrix flow. not observed. Detailed analyses using finite element modeling were performed to support the experimental results. Other artifacts regarding applying hardness testing to determining the tensile properties of metal matrix composites will also discussed. Dynamic Deformation and Fracture Behavior of Novel Damage Aluminum Composites: Discontinuously Reinforced Tolerant M. Irfan Dr. Shen Eng., 861-1 Chongnung-dong Songbuk-ku, Seoul 136-702 South Ko- Seoul 136-702 Chongnung-dong Songbuk-ku, Eng., 861-1 rea behavior of Al-3 wt.% Mg matrix composites Dry sliding wear manufactured by a pressureless infiltra- reinforced with SiC particles Pin-on-disk wear tests under various tion technique was investigated. a were carried out using a hardened steel ball as applied load conditions the of the varying size and volume fraction of counterpart. The effect of the compos- surfaces wear was studied. Worn carbide particle on the debris were also examined with optical and ite together with wear with resistance of the composite increased Wear electron microscopy. and volume fraction of the reinforcing par- the increase of the size was accompanied with low wear rates, while ticle. Mild abrasive wear wear resulted in high wear rates. Subsur- massive severe delamination surface was estimated to correlate the subsurface strain of the wearing rate of the composite. face deformation and cracking with the wear oxide layers formed on Special attention was paid to the role of iron the wearing surface. of Dis- Properties Correlation between Hardness and Tensile Metal Matrix Composites continuously Reinforced but the effect of friction coefficient becomes negligible above 0.3. above negligible becomes friction coefficient effect of but the small. A is also to 0.495) (from 0.01 ratio of Poisson’s The effect lower significantly results in however, rate, strain hardening higher pressure. same applied under the density compaction Compos- Mg Matrix Behavior of Al-3 WT.% Sliding Wear Dry by a Pres- Manufactured with SiC Particles ites Reinforced Infiltration Technique sureless Hyung-Il Kim

WEDNESDAY AM 149 11794-2275 USA York atStonyBrook,Dept.ofMatls.Sci.& Eng., StonyBrook,NY deen ProvingGround,MD21005-5069 USA; rect., AMRSL-WM-MC,Bldg.4600, RodmanMatls.Rsch.Lab.,Aber- Clayton John Derek Demaree Nitride CoatingsProducedby IonBeamAssistedDeposition Effects ofNitrogenontheElectrochemicalPassivationMetal 9:30 AM tions willbepresented. evated temperatureambientenvironments.Observationsandevalua- studied fortheirperformanceunderdryslidingweartestandin el- evaluation ofthedepositedsamples,coatedsampleswerealso synthesis/deposition ofthecoating.Inadditiontomicrostructural employed highpowerNd-YAG laserwithfiberopticbeamdeliveryfor surface tosynthesizerequiredcoatingmaterial.Thepresentwork hicle followedbymanipulationoflaserbeamforscanning the sition ofthecoatingprecursormaterialinawater-basedorganic ve- engineering (LSE)technique.TheLSEtechniqueinvolvedspraydepo- synthesis ofTiCcoatingonAl-alloywasachievedusinglasersurface materials inmanycommercialapplications.Inviewofthispossibility, lightweight andsoftmaterialcanextendtheirusefulnessasstructural involving wearandcorrosion.Suchrefractorycoatingifdepositedon chemical natures,whichmakethemsuitableformanyapplications Refractoryceramiccoatingsaredesirablefortheirphysicaland TN 37388USA Sci. &Eng.,Ctr. forLaserAppl.,B.H.GoethertPkwy., Tullahoma, B. Dahotre TiC CoatingonAl Oxidation andWear PerformanceofLaserSurfaceEngineered 9:10 AM tiveness fortheapplications. rials incastingindustriesandthepresentworkwilldiscusstheireffec- products. Suchcoatingsareintendedforprotectingtoolanddiemate- observed andevaluatedintermsoftypesquantitiesreaction tion. TheeffectsofinteractionbetweenmoltenaluminumandVCare for elementaldistributionandx-raydiffractionphaseidentifica- were employedtoobservetopographicalfeaturesalongwithSEM/EDS coated samplesforvariousdurations.Opticalandscanningmicroscopies for acceleratedcorrosionresponsetoliquidA356Albyimmersingthe synthesis/deposition ofthecoating.Thecoatinghasbeenevaluated employed highpowerNd-YAG laserwithfiberopticbeamdeliveryfor surface tosynthesizerequiredcoatingmaterial.Thepresentwork hicle followedbymanipulationoflaserbeamforscanningthe sition ofthecoatingprecursormaterialinawater-basedorganicve- engineering (LSE)technique.TheLSEtechniqueinvolvedspraydepo- VCcoatingonstructuralsteelhasbeendepositedusinglasersurface Appl., B.H.GoethertPkwy., Tullahoma, TN37388USA nessee SpaceInstitute,Dept.ofMatls.Sci.&Eng.,Ctr. forLaser Dahotre face EngineeredVCCoatingonStructuralSteel Accelerated LiquidMetalCorrosionResponseofLaserSur- 8:50 AM overlay coatings. candidates forfurtherevaluationuseassulfidationresistantweld sistance inmoderatelyreducingenvironments,thesealloysareviable applications requiringacombinationofweldabilityandcorrosionre- to aggressivereducingenvironments.Withthepotentialpromisefor tions ofFe-Alalloys(10wt%Al)showexcellentcorrosionresistance nodules. Theresultsfromthisstudyindicatethatweldablecomposi- failure atlatertimesandthesubsequentgrowthofcorrosionproduct initial formationoftheprotectivescalethatencounteredmechanical 700 opment byanorderofmagnitudewhencomparedtopureironat wt% AlwasobservedtodecreasetherateofouterFeSscaledevel- Growth ofthesescaleswasdiffusioncontrolledandtheaddition5 (less than7.5wt%Al),thickscalesofsulfidephaseswerefound. the formationandmaintenanceofthisscale.Forlowaluminumalloys Increasing thealuminumcontentofalloywasfoundtopromote ° C. Intermediatealuminumcontents(7.5wt%Al)exhibitedthe 2 1 ; ; ArvindAgarwal 1 1 ; Army ResearchLaboratory, Weapons &Matls.Rsch.Di- 1 University ofTennessee SpaceInstitute,Dept. ofMatls. : LalithaR.Katipelli 1 ; Wendy E.Kosik 1 ; LalithaR.Katipelli 1 1 ; ArvindAgarwal ; GaryP. Halada 2 State UniversityofNew 1 ; 1 University ofTen- : Narendra B. 1 2 ; ; CliveR. Narendra : Ikeda Deposited byIonBeamSputteringMethod Synthesis andPropertiesofBN,BCNB/BNThinFilms 10:25 AM 10:10 AMBreak processes toobtainhighqualitymaterialsforfutureapplications. gated. TheauthorsoptimizedthetechnologicalparametersofCVD structure, opticalandmechanicalpropertiesoffilmswereinvesti- The surfacemorphology, chemicalcomposition,bonding means ofFTIR,SEM,opticalspectroscopyandX-raydiffractometry. reactors andinmicroelectronics.Thematerialswereexaminedby application inmanufacturingofcuttingtoolsandmaterialsfornuclear and excellentcorrosionresistanceatelevatedtemperatureshavefound Plasma EnhancedCVD(PECVD).Thelayers,owingtohighhardness Enhanced ChemicalVapour Deposition(MWCVD)at2.45GHzandby drogen (a-C:N:H)filmshavebeendepositedbyMicrowavePlasma Diamond-likecarbon(DLC)andamorphouscarbon-nitrogen-hy- 30, CracowPL30-059Poland 1 and MWCVDTechniques Properties ofDLCanda-C:N:HFilmsLayersGrownbyPECVD 9:50 AM quences ofthisoxyanionformationoncorrosionresistance. oxyanions inthepassiveoxidewillbediscussed,asconse- in thecoatinganddissolvedelectrolyte)onformationof ray photoelectronspectroscopy(XPS).Theeffectofnitrogen(both chemistry ofthepassiveoxidewasexaminedusingangle-resolvedx- havior ofthealloyswasstudiedbyelectrochemicaltechniques,and erford backscatteringspectrometry(RBS),theaqueouscorrosionbe- cal andphasecompositionofthecoatingswereexaminedusingRuth- using 1000eVnitrogenionsande-beamvapordeposition.Thechemi- ized. Inthisstudy, coatingsofCr-NhavebeensynthesizedwithIBAD, sion behaviorofEHCandIBADnitrideshavenotbeenfullycharacter- number oftribologicalapplications,butthedifferencesincorro- (IBAD) arecandidatestoreplaceelectroplatedchromium(EHC)ina Hardnitridecoatingsproducedbyionbeamassisteddeposition resistance offerritic steelduringexposureto100/200 Kabovethe to 100hreveal that LSAmaysignificantlyenhance theoxidation studies inairbythermogravimatric analysisat973and1073Kforup pared to220VHNoftheunderlying substrate.Isothermaloxidation ing LSA,microhardnessoftheAZ increasesto450-550VHNascom- alloyed zone(AZ)arestrongfunction oftheLSAparameters.Follow- tion (determinedbyenergydispersive spectroscopicanalysis)ofthe (studied byopticalandscanning electron microscopy)andcomposi- feed rate.Adetailedinvestigationindicatesthatthemicrostructure routine werelaserpower,scanspeedofthesample-stageandpowder CO2 laser. ThemainprocessvariableschosenforoptimizingtheLSA surface alloying(LSA)withco-depositedCrusingacontinuouswave tion resistance(above873K)of2.25Cr-1Moferriticsteelbylaser Anattempthasbeenmadetoenhancethehightemperatureoxida- UK 721302 India; 1 Resistance Laser SurfaceAlloyingofFerriticSteeltoEnhanceOxidation 10:45 AMInvited in air. over thethermalbehaviorathightemperaturesupto923Kwasstudied FT-IR andESCA.Alsonanoindentationtestwascarriedout.More- ion beamsputteringmethodandcrystalstructurewasinvestigatedby high temperatureswereinvestigated.Thefilmspreparedbythe multilayer ofB/BN.Thehardnessandoxidationresistancefilmsat compared thedifferenceofbehavioramongc-BN,ternaryB-C-Nand and BCNcoatinginducecrackoccurrenceafterdeposition,wehave tance athightemperature.Inordertodoclearthereasonwhyc-BN ings becauseoftheirprominenthardnessaswelloxidationresis- Manyworkershavegivenmuchattentiononc-BNandBCNcoat- yamate, Hirakata,Osaka573-0128Japan 2 Cer. Ctr., C/oNIMC1-1,Higashi, Tsukuba, Ibaraki305-8565Japan; University ofMiningandMetallurgy, Dept.ofElect.,Al.Mickiewicza I. T., Kharagpur, Dept.ofMetallu.andMatls. Eng.,Kharagpur, WB Ion EngineeringResearchInstituteCorporation,4-4-24,Tsuda- 1 ; N.Iwamoto : I. Manna 2 University ofLiverpool,LaserGrp.,LiverpoolL693GH 2 ; 1 1 ; K.KondalaRao Joint ResearchConsortiumofFCT, JapanFine : S. Jonas 1 1 ; ; S.K.Roy T. Stapinski : 1 ; K.G.Watkins S. Kurooka 1 ; E.Walasek 1 ; T. 1 2 ; ;

WEDNESDAY AM 150 Johns 1 ; 1 ; Michael 1 Chungnam 1 Los Alamos 1 ; 1 E. Ma ; 1 ; 2 ; Harriet Kung 1 ; J. P. Hirth ; J. P. 1 ; M. Trexler 1 ; Hyoung Seop Kim 1 C results in powder with a grain size of powder with a grain C results in ° ; Marc Verdier 1 ; T. E. Mitchell ; T. ; K. T. Ramesh ; K. T. 1 2 Sun Ig Hong : Amit Misra : D. Jia Johns Hopkins University, Dept. of Mech. Eng., Balti- Johns Hopkins University, 2 : ; J. D. Embury 1 National University, Dept. of Metallu. Eng., Taedok Science Town, Dept. of Metallu. Eng., Taedok National University, 305-764 Korea Taejon a model on the ductile-brittle transition of partially In this study, crystallized amorphous Al-Ni-Y alloys is proposed. The strength of the partially crystalline Al-Ni-Y alloys was found to exhibit the maximum when the size of Al particle is 10 nm. Partially crystallized Al- Ni-Y alloys were also found to be brittle when the size and the volume fraction of the Al particles exceeded the optimum values. On the assumption that the diffusivity of Y is so low that Y atoms rejected more, MD 21218 USA Fe and W-based alloy powders with nanoscale grain sizes were produced by mechanical milling at room temperature. These powders were subsequently consolidated to full density bulk samples. The consolidated samples have grain sizes in the 50 nm to 1 micron range. Quasistatic and high-strain rate (Kolsky bar) tests have been conducted on these samples to determine the dependence of strength, strain hardening, and strain-rate sensitivity on grain size. ductility, The consolidation behavior with and without second-phase additions, the mechanical response under quasistatic versus dynamic conditions, and the potential of such alloys for kinetic energy penetrator applications are discussed. 9:40 AM Amorphous Crystallized of Partially Ductile-Brittle Transition Al-Ni-Y Alloys Zn(Al) alloys with a lower melting temperature such that room tem- that room such melting temperature a lower alloys with Zn(Al) size 1 micron grain for behavior show superplastic is 0.45 Tm perature of a results here preliminary report We temperature. at room samples at powder milled attrition. Zn mechanical by of nc Zn prepared study high ductility size pellets due to its forms 3-6 mm room temperature grain size pellets have an internal cold-welding. These and extensive Milling at -180 of 25-30 nm. diffraction calorimetry and x-ray Differential scanning about 20 nm. and subse- changes with milling time follow the structural were used to with stored enthalpy and microstrain Maxima in both quent annealing. which implies a change in deformation milling time are observed, grain size. Results of preliminary mechani- mechanism with decreasing on the nc Zn will be presented. cal property measurements 8:55 AM Invited in Ultra-Fine Scale Metallic Strengthening Mechanisms Multilayers MS K765, MST-CMS, Div., Sci. and Tech. Matls. National Laboratory, NM 87545 USA Eniwetok Rd., Los Alamos, multilayers may be synthesized to have Ultra-fine scale metallic are the theoretical strength. These materials strength levels close to the effects of length scales in plastic defor- also ideal for investigating the microstructure from mation of metallic materials. Refinement of give rise to different the micron-scale to the nanometer-scale may (classical Hall-Petch), deformation modes involving continuum pile-up dislocation (Orowan). discrete pile-up (modified Hall-Petch) and single creep may be operative Diffusion-based mechanisms such as Coble in the nanom- causing softening below a critical microstructural-scale a range of fcc/fcc and eter range. Mechanical property results from residual stresses, shear fcc/bcc Cu-based multilayers having different misfit strain between lay- moduli mismatch between layers and lattice layer thickness and grain ers will be presented. The relative effects of the construction of size within the layers will be elucidated through and grain size ranges two-dimensional maps that show layer thickness operate. By correlating over which different deformation mechanisms experimental data, we the deformation mechanism maps with the interpreting the scale- show that these maps serve as guidelines for in multilayers The dependent strengthening or softening mechanisms influence the transition effects of factors besides length scale that may This research is spon- from one mechanism to another are discussed. sored by DOE-OBES. 9:20 AM Ultrafine-Grained Fe Quasistatic and Dynamic Properties of and W Alloys Baltimore, MD Dept. of Matls. Sci. and Eng., Hopkins University, 21218 USA; Nastasi ; W. 1 I. Manna : North Carolina State 1 ; University of Liverpool, 1 2 Carl C. Koch ; I. I. T., Kharagpur, Dept. of Metallu. and Dept. of Metallu. Kharagpur, I. I. T., 1 1 Rajiv S. Mishra, University of ; 2 Room: Polk A/B Location: Opryland Convention Center Rajiv S. Mishra, University of Missouri, Materials Processing and Manufacturing ; K. G. Watkins : Xinghang Zhang 2 8:30 AM Invited Processing, Characterization, and Properties of Nano-crystalline Zinc Matls. Sci. and Eng. Dept., Raleigh, NC 27695 USA University, Zinc is an interesting metal to study deformation behavior of nanoscale microstructures. A study of nanocrystalline(nc) Zn prepared by a gas condensation method with grain sizes of 8-30 nm exhibited plastic deformation in compression at room temperature but failed in the elastic regime in tension. This is behavior typical of many nc materials at room temperature, but room temperature is 0.42 Tm for Zn. Superplasticity has been reported for nc Ni at 0.36 Tm. Dilute Wednesday AM Wednesday Dept. of Metallu. Eng., Rolla, MO 65409 USA Division, Powder Metallurgy Committee, Shaping and Division, Powder Metallurgy Committee, Forming Committee Program Organizers: MO 65409-0340 Missouri, Metallurgical Engineering, Rolla, Director- Materials Laboratory, USA; S. L. Semiatin, Wright Colorado ate, Dayton, OH 45440 USA; C. Suryanarayana, and Materials School of Mines, Department of Metal Engineering, Golden, CO 80401 USA; Naresh Thadhani, School of Materials of Technology, Institute Georgia Science and Engineering, Atlanta, GA 30332-0245 USA March 15, 2000 Session Chair: Sponsored by: Ultrafine Grained Materials: Mechani- Ultrafine Grained Materials: Mecha- cal Behavior and Strengthening nisms: I M. Steen WB 721302 India; Matls. Eng., Kharagpur, L693GH UK Laser Grp., Liverpool an stimulation in cochlar implants necessitate Electrodes for neural and good drawability. injection/emission capacity extremely high charge Ir is known to possess one of the largest charge Multi-layered activated and brittle. On the other Ir is expensive However, carrier density. an cheap, ductile and bio-compatible. Recently, is relatively hand, Ti a Ti-based electrode with an Ir-rich Ir-Ti attempt was made to develop is surface alloying (LSA). The present study alloyed zone (AZ) by laser of the microstructure, surface- aimed at a detailed characterization in the AZ of such an electrode pre- chemistry and phase-distribution LSA with an earlier determined optimum with Ir. pared by LSA of Ti appears to develop an AZ that can be conve- processing conditions characteristic micro- niently divided into three regions with distinctly the LSA parameters on structure and composition. The influence of are discussed. Ac- identity and distribution of phases the morphology, proposed to account for the a metastable phase diagram is cordingly, polarization tests reveal observed microstructure. Potentiodynamic significantly following a that the amount of charge injected increases an attempt was made to correlate the micro- special etching. Finally, with the electro- structure and composition of the AZ or electrode-tip for neural stimulation. chemical response, and assess its suitability current upper limit of use of the same steel for heat exchangers in heat exchangers steel for of the same of use upper limit current that suggests analysis microstructural Post oxidation reactors. thermal the im- for is responsible Cr2O3 layer continuous and an adherent detailed structure-prop- a Finally, resistance. in oxidation provement be reported. correlation will erty-LSA parameter AM 11:10 of Ti with Surface Alloying Evolution in Laser Microstructural Electrodes Neural Stimulation Ir for Developing

WEDNESDAY AM 151 considered anddiscussed aswell. shown. Theexamples ofpracticalapplications SPDmaterialsare plasticity atlowtemperaturesand highstrainratesinSPDalloysis processed nanostructuredmaterials forstructuraluse.Enhancedsuper- demonstrated. Specialattention is stressedondevelopmentofthe attaining veryhightensileandfatigue strengthinSPDmaterialsare temperature, strainandrates andothers).Theexamplesof with detailsofSPDprocessing(applied method,processingroutes, From theotherhand,thesemicrostructuralparametersareassociated crystallographic textureandoftenachangeofphasecomposition. grain sizes,butalsospecificdefectstructures,highinternalstresses, of SPDmaterialsitistypicaltohaveapresencenotonlyverysmall eral puremetalsandalloys.Ithasbeenshownthatformicrostructures relationship: SPDprocessing-nanostructures-newproperties,forsev- processing andmicrostructuralparameters.Thispaperfocuseson the such propertiesisacomplexproblem,whichdependsondifferent achieve theirnewandextraordinaryproperties.However,attaining nanostructures inmetallicmaterials;therefore,thereisapotential to lead toastrongrefinementofmicrostructureandformation of ultrafine-grained metalsandalloys.MethodsofSPDprocessingcan der highimposedpressureisthenewtechniqueforfabrication of Severeplasticdeformation(SPD),i.e.intensestrainingun- 450000 Russia University, Instit.ofPhysicsAdv. Matls.,K.Marksstr., 12,Ufa in MetallicMaterials Developing ofSPDProcessingforEnhancementProperties 10:30 AMInvited 10:20 AMBreak was dependentontheWCparticlesize. mean freepathandWC/WCcontiguity. Thehardnessofhardmetals 0.4. ThetransverserupturestrengthwassensitivelydependentonCo size wasabout600nmandtheWC/WCcontiguitylowervalueof However, incaseoftheaddition0.7%Cr3C2/VCinhibitors,WC was about300nmandtheWC/WCcontiguitymeasuredas0.7. 10nm. Incaseoftheaddition0.7%TaC/VC inhibitors,theWCsize tated Cophasewasfcccrystalstructureandtheaveragesizeabout eted WCgrainsinsinterednanocrystallinehardmetals.Theprecipi- inhibitors. ItwasobservedthatCophaseprecipitatedwithinfac- and WC/WCcontiguityweresensitivelydependentonadditionof The microstructuralparameterssuchasWCsize,Comeanfreepath into nanocrystallineWC-10Cohardmetalsasgraingrowthinhibitors. pressure of1mtorr. Varying amountofCr3C2,TaC andVCwereadded mixed withCopowdersandfollowedbysinteringat1375°Cunder hardmetals, thecommercialWCwith0.57-1.27mmpowderssizewere microstructures andmechanicalpropertieswithnanocrystalline were sinteredat1375°Cunderpressureof1mtorr. To comparethe 5:1 for24hrsanddriedindryingoven.Themixedpowders The powderswereball-milledinn-Hexanewithball-to-powderratioof size wasabout100nmandmixedhomogeneouslywithCobinder. ders byfollowingmechano-chemicalprocess.TheinitialWCpowder The precursorpowderswerereducedandcarbonizedintoWC/Copow- prepared byspraydryingofsolutioncontainingsaltsWandCo. hardmetals wereinvestigated.Nanocrystallineprecursorpowders ThemechanicalpropertiesofnanocrystallineWC-10Co-X Sangnam-dong, Changwon,Kyungnam641-010Korea Institute ofMachineryandMaterials,Dept.Matls.Processing,66, Eng., 373-1Kusong-dong,Yusong-gu, Taejon 305-701Korea; Advanced InstituteofScienceandTechnology, Dept.ofMatl.Sci.and Soon HyungHong Mechanical PropertiesofNanocrystallineWC-CoHardmetals 10:00 AM data available. the Yaccumulationmodelareingoodagreementwithpublished face layersreachedthecriticalvalue(20%).Thepredictionsbasedon loys wereassumedtobecomebrittlewhenthesolutecontentofinter- were derivedbybalancingthequantityofeachelement.Al-Ni-Yal- Al particles,Yaccumalatedinterfacelayersandamorphousmatrix, solution isreadilyattainedinthematrix,reactionthreeregions, diffusivity ofrejectedNiatomsissohighthattheperfectlymixed from FCC-Alparticlesarelimitednearinterfaceregionandthe 1 ; SeungIlCha : R. Z.Valiev 1 ; B.K.Kim 1 ; 1 Ufa StateAviation Technical 2 ; G.H.Ha 2 ; 1 2 Korea Korea : Alloys forHighTemperature Applications Structure/Property RelationsofRapidSolidifiedAluminum 11:35 AM effect ofdispersedoxideparticlesonthestrengthandductility. strength andductility, (4)oxideparticlesizeandmillingtime,(5) grain structureandoxygencontent,(2)strengthsize,(3) per, wewilldiscussrelationshipbetween(1)formationofultrafine- microstructure observationforthesteelswerecarriedout.Inpa- sist ofaferritephaseandfineparticlesFe3O4.Tensile testand long and11mmindiameterat973K.Theultrafine-grainsteelscon- milled inanargonatmosphereandthenhotrolledintobars,600mm compositions intherangeof0.2-1.5wt%oxygenweremechanically using powdermetallurgymethod.Severalkindsofironpowderswith ultrafine-grain steelswithagrainsizelessthan1micronwereproduced might beeffective forimprovingstrainhardening.Inthisstudy, the rateofstrainhardening.Dispersionfineparticlesinmatrix strength-elongation balanceofultrafine-grainmaterialstobeimproved size issufficientlyfine.Therefore,itnecessaryforkeepinghigh bility occuratroomtemperatureandnormalstrainratesifthegrain decreasing grainsize,namely, increasingstrength.Strongplastic insta- the otherhand,ductility, especiallyuniformelongation,decreaseswith Strengthofalloysincreasesstronglywithdecreasinggrainsize.On Ibaraki 305-0047Japan Metals, FrontierRsch.Ctr. forStructuralMatls.,1-2-1Sengen,Tsukuba, ity ofUltrafine-GrainSteels Effect ofDispersedOxideParticlesontheStrengthandDuctil- 11:15 AM of SPTS-processedalloys. are discussedandexplainedusingresultsofmodelingdefectstructures hysteretic properties.Theoriginofmetastablestatesandagingeffects unique mechanical(veryhighstrength,superplasticity)andmagnetic heating agingeffectstakeplaceandprocessedalloysdemonstrate amorphization ofintermetallicsphasesinthesealloys.Duringfurther cessing hasresultedinformationofsupersaturatingsolidsolutionsand by TEM,X-raystudiesandmagneticmeasurementsthatSPTSpro- Al-based alloysandhardmagneticNd(Pr) processing bysevereplastictorsionstraining(SPTS)ofseveralTiand states inbulksamplesofvariousalloys.ThispaperfocusesonSPD and changeessentiallyaphasecompositionforminghighlymetastable ability ineitherstronglyrefinemicrostructuretillupnanometerrange Bynowitiswellestablishedthatsevereplasticdeformationhasan Instit. ofPhysicsAdv. Matls.,K.Marksstr., 12,Ufa450000Russia Stolyarov Aging EffectsinBulkMetastableNanostructured Alloys 10:55 AM achieved throughproperheattreatmentprocesses. processing andheattreatmentconditions.Optimalpropertiescan be the alloysresultingfromrapidsolidificationwasseentovarywith establish structure/propertyrelationship.Themetastablestructure of nation ofthealloyswereconductedandresultsanalyzed to rates ofgasatomization.Mechanicaltestingandmicroscopyexami- samples ofthealloyswerepreparedbyP/Mprocesswithhighcooling investigated forpotentialhightemperatureapplications.Thebulk Several newlydevelopeddispersionstrengthenedaluminumalloyswere temperature applicationsbecauseoftheirlightweightandlowcosts. process areofincreasinginteresttomaterialsresearchersforelevated Dispersionstrengthenedaluminumalloysviarapidsolidification Silver Ln.,EastHartford,CT06108USA Giamei Yuuji Kimura 1 ; 1 ; R.Z.Valiev 1 United Technologies ResearchCenter, MS129-22,411 1 ; KaneakiTsuzaki 1 ; 1 Ufa StateAviation Technical University, : Yoshikazu Sakai 1 ; 1 National ResearchInstitutefor 2 Fe 14 B basedalloys.Itisshown : 1 ; MinoruOhtaguchi S. G.Song 1 : ; A.F. .V. V. 1 ;

WEDNESDAY AM 152 : : M. : , the critical c phase as their The Institute of γ 2 Tokai University, Tokai 1 phase showing the ; δ 2 phase inherited into the δ NASA, SD 47, MSFC, Hunts- NASA, SD 47, 2 phase was nucleated secondary after ; K. Kuribayashi 1 δ Universita di Bologna, Dept. di Fisica ed 1 ; UAH, SD47, MSFC/NASA, Huntsville, AL MSFC/NASA, Huntsville, UAH, SD47, 1 3 Queen’s University, Dept. of Matls. and Metallu. University, Queen’s ; I. Jimbo 1 where x is from -2 to +2, was successfully levi- where x is from -2 to +2, was successfully 2 6-x ; 1 Mo 18+X ; R. Tognato 1 Ni 76 ; T. Aoyama T. ; 1 equilibrium primary phase, undercooling higher than T equilibrium primary phase, undercooling higher Instituto Nazionale di Fisica della Materia, Alma Mater Studiorum, Berti Pichat 6/2, Bologna I-40127 Italy Viale TEM, SEM and AFM observations were carried out in order to investigate the SiC-Al interface after different unidirectional solidification rates. The morphology of the interface is examined taking into account the important role played by the SiC whisker surface on the faceted or not faceted growth of the Al Matrix. 4:00 PM Solute Diffusion in Dilute Liquid Metals and Metalloids Smith Reginald W. Eng., Kingston K7L 3N6 Canada It is now well known that the diffusion coefficient (D) measured in a laboratory in low earth orbit (LEO) is less than the corresponding all LEO laborato- However, value measured in a terrestrial laboratory. ries are subject to transient accelerations (g-jitter) superimposed on the steady reduced gravity environment of the space platform. This paper reports recent measurements of the diffusion coefficients for dilute binary alloys of Pb-(Ag, Au, Sb), (Sb-(Ga, In), Bi-(Ag, Au, Sb), Sn-(Au, Sb), Al-(Fe, Ni, Si) and In-Sb in which g-jitter was suppressed. tated by the electromagnetic levitation furnace. More than 300 K of tated by the electromagnetic levitation furnace. whose Ni content is undercooling was achieved. Although the alloy has the higher than that of the eutectic composition nucleation of both phases temperature where the activation energies for the are equilibrated, promotes the nucleation of MSFC/NASA, Huntsville, AL 35812 USA; Huntsville, AL 35812 MSFC/NASA, USA; ville, AL 35812 35812 USA were studied immiscible alloys growth in Cu-Co metastable Droplet the popula- numerical modeling of experiments and by undercooling Increasing undercooling resulted in droplet tion dynamics equations. cooling. From the isothermal treatment coarsening during continuous the time evolution of droplet size distribu- at a certain undercooling, which can be divided into two regions: dis- tion has been determined structure. For the droplet growth in the former, persed and non-uniform experiments and modeling of gravita- there is agreement between whereas for the latter, experiments devi- tional-induced coalescence, the system is out of dispersion. Calcula- ate from calculations because coalescence caused by Stokes settling tions also show that droplet that by Marangoni migration on the ground- considerably prevails over is though mass density of liquid Cu and Co based experiments, even very close. 3:00 PM Melt Solidification of Fe-Ni-Mo Alloy from Undercooled Murata Kuribayashi, 3-1-1 Instit. of Space & Astro. Sci., c/o Kazuhiko Sagamihara, Kanagawa 229-8510 Japan; Yoshinodai, Space and Astronomical Science as one of the structural The 18%Ni maraging steel is well known properties in strength materials that have well balanced mechanical observed the degrada- and toughness. However, there has been often weld joint. One of the tion of these mechanical properties in the reasons for the degradation is the metastable rapid solidification behav- ambient temperature. In the present study, alloy that is the base ior from undercooled melt of Fe-Ni-Mo ternary The drop of the alloy of the maraging steel was precisely observed. Fe alloy, pronounced recalescence. The observed clearly by the the first recalescence. These behaviors were high-speed video camera. 3:20 PM Break 3:40 PM Effects of Directional Solidification Rates on Aluminum Ma- trix Structures Reinforced with 23% Oriented SiC Whiskers C. Patuelli Uni- 1 ; J. C. 1 ; 1 NRC, SD47, 1 WEDNESDAY PM WEDNESDAY ; 3 Rensselaer Poly- 1 M. B. Koss ; 2 : ; James E. Smith 1 ; V. Pines ; V. 2 ; Tom J. Rathz ; Tom 2 ; Saiyin Ye 1 ; A. Chait 1 Robert Schiffman, R.S. Research Inc., Robert Schiffman, R.S. Room: Memphis A Location: Opryland Convention Center Yubin He Yubin : Michael R. Fiske, Morgan Research ; Mike B. Robinson ASM International: Materials Science ASM International: 1 ; M. E. Glicksman 1 Delin Li : NASA Glenn Research Center, Computational Microgravity Lab., 2 Cleveland, OH 44135 USA Dendritic solidification is a common mode of solidification. It is also an important model problem in non-equilibrium physics and pattern formation physics. Current theories couple the transfer of latent heat with selection mechanisms at the interface. Measurements of succinonitrile (SCN) dendrites in microgravity show reasonable agreement between heat transfer predictions and experiment. However, data and analysis for assessing interfacial physics theories are less are studying, and will present data on, transient effects definitive. We employ the Clapeyron pressure/melt- in dendritic growth of SCN. We hydro- change in a sample’s to make a rapid ing temperature effect melting static pressure, and thereby rapidly change the specimen’s temperature, forcing the dendrite to select a new steady-state. These initial measurements show some surprising and non-intuitive effects. 2:40 PM Droplets Coarsening in Copper-Cobalt Metastable Immiscible Alloys versity of Alabama, Dept. of Chem. and Matls. Eng., Huntsville, AL versity of Alabama, Dept. of Chem. and Matls. 35899 USA processed in microgravity Samples from Fe-Cu and Co-Cu systems Pore filling, showed considerable pore formation and metamorphosis. samples. Pores showed coarsening and pore migration was found in most fraction. These be- bifurcated behaviors based on their liquid volume growth and differ- haviors result from particle rearrangement, particle interfacial energy different diffusion patterns that associated with the interface between ences, instabilities, and grain coarsening along exists throughout the entire process and domi- diffusion phases. Volume However, low liquid vol- nates in high liquid volume-fraction samples. which results in ume fraction and the presence of the agglomeration, surface diffusion during high local solid volume fraction, enhances the volume diffusion and the process which causes the pore breakup. Both In this paper, a surface diffusion contributes to the pore migration. presented to monitor the pore bifurcation and migration model will be trends of shape changes of a pore in a microgravity. 2:20 PM in Dendritic Solidification Effects Transient LaCombe NY 12180-3590 USA; 8th St., Troy, technic Institute, CII 4225, 110 Corporation, Matls. Sci., Huntsville, AL 35805 USA Corporation, Matls. Sci., Huntsville, AL March 15, 2000 Session Chair: 2:00 PM Liquid Phase Sinter- Pore Bifurcation and Migration During ing in Microgravity Wednesday PM Wednesday Barton, VT 05822 USA; Carlo Patuelli, Universita di Bolo- Barton, VT 05822 USA; Fisica, Bologna I-40126 Italy gna, Departimento di Critical Technology Sector, Electronic, Magnetic & Photonic Electronic, Magnetic Sector, Critical Technology Structural Materials Division, Alloy Materials Division, Thermodynamics & Phase Equilibria Phases Committee, Committee Program Organizers: Sponsored by: 12th International Symposium on Ex- on Symposium 12th International for Microgravity Methods perimental Session 4 Science: Materials

WEDNESDAY PM 153 Robert R.Jayroe users withaneasy-to-handle tool.ItcombinesBayer processknow- “experts.” Thesimulation model“ClickSim”provides abroadrangeof Successful utilizationofsuchamodel wasoftenrestrictedtoafew mization ofdesign,operationand energyissuesinanaluminaplant. TheBayerprocesssimulation model isavaluabletoolfortheopti- Engineering Services,Weiherweg 19,Volketswil 8604Switzerland ClickSim-Bayer ProcessSimulation Model 2:00 PM Montreal, Quebec,Canada Session Chair: March 15,2000 Wednesday PM Limited, Gladstone,Queensland4680Australia Pittsburgh, PA 15219USA; JoeAnjier, Queensland Alumina Program Organizers: Sponsored by: Chemistry Optimization Alumina andBauxite:BayerProcess flight. describes performancecapabilitiesoftheEMscurrentlyplannedfor the resources,services,andallocationsavailabletoEMsbriefly date avarietyofmaterialsscienceinvestigations.Thispaperdiscusses various multi-userEMsthatwillbeexchangedin-orbittoaccommo- European SpaceAgency. Theother EM positionwillbeoccupiedby NASA/ESA EMbeingdevelopedcollaborativelybyNASAandthe the InternationalSpaceStation(ISS).OneoftheseEMswillbe accommodate twoExperimentModules(EM)simultaneouslyonboard Science ResearchFacility(MSRF)isamodularfacilitydesignedto TheMaterialsScienceResearchRack1(MSRR-1)ofthe AL 35812USA Inc., NASA/MSFC,MicrogravitySci.&Appl.Div., SD42,Huntsville, MSFC Alabama,SD42,Huntsville,AL35812USA; national SpaceStation the MaterialsScienceResearchRack1(MSRR-1)onInter- Materials ScienceExperimentModuleAccommodationwithin 4:40 PM rheological behaviour. describing theformationofthistypemicrostructuresandtheir order toprovidebenchmarkdataforthevalidationofmodels sis isputontheimportanceofmeasuringthesedifferentquantitiesin tal, anddistributionoftheorientationsdendriticbranches.Empha- internal andexternaleutecticfractions,developedsurfaceofthecrys- perpendicular tothesolidificationdirection:envelopeofgrain, were systematicallydeterminedonsectionstakenbothparalleland light, SEM),ispresentedhere.Thefollowingmorphologicalfeatures mentary metallographictechnics(opticalmicroscopyunderpolarized structures byusingoriginalImageAnalysistoolsandseveralcomple- tion rateevidenced.Thequantitativecharacterizationofthesemicro- microstructures wereobtainedandtheirdependenceonthesolidifica- the STS-95mission(November98).Homogeneousmultigrainequiaxed formed withseveralvelocitystepsduringtheAGHF6experimentin DirectionalsolidificationofarefinedAl-3.5%Nialloywasper- Martyrs, Grenoble,Cedex938054France Conditions 3.5Wt%Ni Directionally SolidifiedUnderDiffusive Transport Characterization ofEquiaxedMicrostructuresinRefinedAl- 4:20 PM jitter present.Thesignificanceoftheseresultswillbereviewed. suppressed ratherthanD It wasfoundinallalloysystemsthatD : S. VerrierS. 2 ; Light MetalsDivision,AluminumCommittee K. I.Verghese, AlcanInternational, Ltd., 1 NASA/MSFC, MicrogravityMatls.Sci.Appl.Dept., 1 Location: OprylandConventionCenter Room: JeffersonB ; : χ Vito Cedro,AlcoaWorld Alumina, T 1 Dinah B.Higgins DEM/SPCM, CEA-Grenoble,17RueDes 2 asobservedbyearlierworkerswithg- χ T (temperature)ifg-jitterwas 1 ; KevinS.McCarley : Karek Fort 2 Pace &Waite 1 ; 1 KF 1 ; Pierre Castelli Process ControlinAluminaRefining-AnAutomatedPlant 3:15 PM observed. unlikely thatanydetrimentalimpactonprecipitationyieldwill be result, shouldanyproductpassbeyondthefiltrationstepitishighly tion conditionsisordersofmagnitudegreater(upto1000ppm).As a impact ofthisproductontrihydratecrystallisationunderprecipita- stabilise aluminateinsolutionfiltrationisunder10ppmwhile the to increasedproductionyield.Thedoserateof85711required to allow increaseduptakeofaluminavaluesindigestionanddirectlylead aluminate infilterscandirectlypreventprecipitationandthismay mum aluminateconcentrationintheliquor. Animprovedstabilityof prevent precipitationinthefiltersbymaintainingaless-than-opti- tional andmaintenanceissuesassociatedwithfiltration.Manyplants reduce hydrateprecipitationinthefilters.Thisreducesopera- aluminate insolutionunderfilterconditions.Thisimprovementcan been showninavarietyoftestregimestoimprovethestability the filters.ApplicationofNalco85711tosettleroverflowliquorhas it oftenleadstosubstantialoperationandmaintenanceproblemsfor alumina. Whilesuchprecipitationresultsinonlyasmallproductloss in thisfiltrationstepistheprecipitationofsmallmassestrihydrate removed byafiltrationstep.Oneoftheproblemsoftenencountered thickening/settling withremainingmudsolidsintheoverflowliquor Typical Bayeroperationsinvolveseparationofwastesolidsthrough Australia, 2RichardsonSt.,Kwinana,West Australia6167 Mud Filters Scale ControlandPreventionofHydratePrecipitationinRed 2:50 PM understanding andoptimisinglimeefficiency. aluminate arereported.Thekineticinformationhasassistedinboth the monocarbonatespeciestoeithercalciumcarbonateortricalcium tions andproductquality. Studiesofthekineticsdecomposition on phosphateandcalciaintheliquorthatcanaffectbothplantopera- opportunities weredifficulttorealisebecauseoftheinteractiveeffect bauxite andthecausticityofliquorisrelativelylow. Someofthe where themajorityofcarbonateaddedtoliquorcircuitisin ticity wereidentified,especiallyforWestern AustralianRefineries in AlcoaWorld Aluminaplants.Opportunitiestoincreaseplantcaus- been usedincarbonatebalancemodelstohelpoptimisecausticisation called monocarbonateorhydrocalumite).Theequilibriumdatahave proximate composition3CaO.Al2O3.CaCO3.11H2O(commonly intermediate thatisformedalmostinstantaneouslyandhastheap- both atheoreticalandpracticalstandpoint;thereactioninvolvesan liquor composition.Thecausticisationreactionhasbeenstudiedfrom calcium aluminate,hasathermodynamicequilibriumthatdependsupon to sodiumhydroxide,withtheformationofcalciumcarbonateand Thecausticisationreactionusinglimetoconvertsodiumcarbonate tralia Rsrch. &Dev., CockburnRd.,Kwinana,Western Australia6167Aus- Liquor Causticisity The EquilibriumApproachtoCausticisationforOptimising 2:25 PM on examplesofproblemsolvingsuchasplantwaterbalance. users todeveloptheirownunits.Thepaperpresentsthemodelbased chemical reactions;steamandpowergeneration;thepossibilityfor contain mainchemicalsolidandliquidcomponents;allsignificant easy-to-use GraphicalUnerInterface;massandenergybalance;streams how withobject-orientedsoftware.Somefeaturesofthissoftwareare: the newProduction Organization(startedupin parallelwiththe alumina plantatSaintNicolas(Greece). Itwilldescribeinthreeparts opment at“AluminiumdeGreece”, concerningtheautomationofits The followingpresentationwilladdress the3yearprojectunderdevel- possible andcost-effective,bymeans ofcontrolledinvestmentprojects. workforce organizationsystems andautomateprocesseswhenever Nowadays,tocreateaddedbusiness value,itisimperativetomodify Greece 2 1 Aluminium DeGrece,ParaliaDistomou,SaintNicolas,Beotie32003 Aluminium Pechiney, Aluval-BP07,Voreppe, Cedex38341France; : 1 John D.Kildea ; BernardBosca : Gerald I.D.Roach 1 ; SophyGotsis 2 ; ChristosApostolakis 1 ; 1 ; AnnaThomas 1 Alcoa World Alumina, 2 ; NikosCostis 1 ; 1 Nalco 2 : ;

WEDNESDAY PM 154 : : Northwest 1 ; 1 Slovak University 1 ; 2 Craig W. Brown Craig W. : 2820 Seventh Street, Lower Burrell, 1 ; 2 ; Henrik Gudbrandsen John Chen, University of Auckland, John Chen, 2 Room: Sewanee Convention Center Location: Opryland Hydro Aluminium Metal Products, Oslo N-0246 2 Mark P. Taylor, Comalco Aluminium Ltd., Comalco Aluminium Taylor, Mark P. Light Metals Division, Aluminum Committee Division, Aluminum Light Metals ; Halvor Kvande 1 SINTEF Materials Technology, Electrolysis Grp., Trondheim SINTEF Materials Technology, ; Sverre Rolseth 2 1 Aluminum Technologies, Rsrch. Dept., 3950 Sixth Ave. NW, Seattle, NW, Rsrch. Dept., 3950 Sixth Ave. Aluminum Technologies, 98107 USA WA The research presented addresses a novel total system concept as an alternative to conventional Hall-Heroult technology for aluminum N-7465 Norway measurements has been A method of continuous current efficiency cell is a semi-large on developed for use in a laboratory cell. The achieve minimal laboratory scale, with a 42 mm diameter anode. To back and side reactions the cell was designed based on the following: all metal parts of the cell (holders, supporting wires, etc.) were covered with alumina shielding, used graphite crucible, with inner alumina lining, was covered with TiB2 paste and copper cathode was used to form Cu-Al alloy with a low aluminium activity in the melt. Electrolytic carbon consumption tests have been performed with PB-anodes samples. The tests were carried out in a newly developed apparatus where the anode gases were analysed continuously for CO and CO2 during the whole experiments, lasting 12 hours. Argon with known flow rate was used as inert carrier gas. This enabled us to make a total mass balance with respect to the amount of CO and CO2 evolved in the experiment. This amount was compared to the weight loss of the anode sample determined after the experiment. In the calculations of the weight loss of the anode corrections were made for the ash content and bath that had penetrated into the anode during electrolysis. 2:55 PM Slurry-Elec- Laboratory Experiments with Low-Temperature Alumina Reduction Cells trolyte Aluminum Reduction Technology: Cell Technology: Reduction Aluminum Operation/Innovations by: Sponsored Program Organizers: Engineering, of Chemical & Materials Department J. Kipouros, Dalhousie New Zealand; Georges Auckland, Department of Mining and Metallurgical University, NS B3J2X4 Canada Engineering, Halifax, PM Wednesday March 15, 2000 Session Chair: 4001 Australia Brisbane, Queensland, 2:00 PM Electrochemical Reduction of Alumina Thermodynamics of Haupin Warren 15068 USA; PA Norway the theoretical minimum An updated calculation is presented of alumina to aluminum us- energy required to electrochemically reduce in the process, or inert ing either carbon anodes, which are consumed enthalpy of reaction, anodes. Knowledge of this energy (the standard calculations. The re- or deltaH°) is required for making heat balance is calculated from the versible cell potential, or Nernst potential, the activities of reac- standard Gibbs energy of reaction, deltaG°, and calculating cell voltage. tants and products. This value is needed for analysis by The present calculations update the 1976 thermodynamic upon floury alpha. Today Bratland, Grjotheim and Krohn. It was based changes deltaH°. gamma alumina. This largely the cell feed is sandy, of the reversible However, the greatest difference is in the calculation potential. 2:30 PM Studies in a Labo- Carbon Consumption and Current Efficiency Balance Method ratory Aluminium Cell Using the Oxygen Jan Hives Radlinskeho 9, Bratislava 81237 Tech., Inorganic of Technology, Slovakia; ; Scott ; Steve 2 1 Bayer Consultant, R. 2 ; Paul Hackett 1 ; Winston Rennick 1 Alcoa Australia, Alcoa Wagerup, P.O. Alcoa Wagerup, Alcoa Australia, 2 Nalco Chemical Company, 2 Anderson St., 2 Anderson Company, Nalco Chemical 1 : Sana U. Khan : Sana U. ; 1 Paulo Marcio Figueiredo : F. W. Williams, Alcoa World Alumina, Pt., Comfort, Alcoa World Williams, W. F. Alcan Aluminio do Brasil Ltda., Av. Americo R. Gianetti, Alcan Aluminio do Brasil Ltda., Av. John T. Malito John T. 1 Summary of Workshop Sponsored by the Aluminum Sponsored Summary of Workshop ;

1 ; 2 Saramenha P.O. Box 1, Ouro Preto, MG Brazil; Saramenha P.O. Association: Ostap R. 3, Bath, Ontario K0H 1G0 Canada alumina from the Ouro In recent times the calcium content of high as 0.10% (as CaO). Pretor refinery has increased steadily to as soluble calcium entering The bulk of this contamination arose from Investigations showed the liquor across the polishing filter presses. content of the that the monocarbonate (3CaO.Al203.CaCO3.11H2O) mg/l, probably due to filter precoat was dissolving to levels up to 100 In contrast, a precoat the high organic carbon content of the liquor. to only 15 mg/l. composed of tricalcium aluminate (TCAS) dissolved while giving a better coverage of the filter cloth plus a Unfortunately, resulted in significantly low soluble calcium in liquor, the fine TCAS restored by significantly lower filtration rates. The rates were largely reducing precoat thickness and by taking advantage of the improved cloth permeability afforded by the greater protection offered by the new precoat material. As a result of these changes, CaO in product has returned to less that 0.04% while maintaining production at target levels. 4:40 PM and Utili- Roadmap for Baurite Residue Treatment Technology zation: TX The treatment and use of bauxite residue was the focus of a recent workshop sponsored by the Aluminum Association. Industry represen- tatives were joined by several external technical experts to discuss various approaches and set priorities for possible collaborative research. Key technical, economic, environmental, and market factors approaches. Priority areas targeted were used to rank a large number of evaluate the potential recovery for additional research were to further of metals from the residue, explore the removal of desilication product (DSP) before it becomes residue, and to develop new separation technology to enable bauxite beneficiation. These and other results from the technology roadmap will be more fully discussed. Barham NSW 2019 Australia; Botany, 6215 Australia Australia Western Box 84, Waroona, of generally remove solids by a combination Alumina refineries In such processes 99.5% of the mud sedimentation and filtration. flocculation in settling vessels and less than 1% solids are removed by by filtration where the settler overflow of the mud solids are removed sand filters. pressure and less commonly, liquor is passed through hexahydrate (TCA) is used within the Bayer Tricalcium aluminate aid during filtration of the sodium aluminate process as a filtration studies which show that the filtration per- liquors. This paper details with reduced TCA to mud ratios when formance can be maintained resulting from is used. The savings Aid (GLFA) Green Liquor Filtration Alterna- outweigh the cost of using GLFA. reduced TCA significantly may be realized by adding the improved filtration performance tively, mud ratios. In either case, substantial ben- at constant TCA to GLFA of the laboratory results efits are available. Mathematical analysis adequately models allows the development of an algorithm, which ratio and GLFA filtration performance as a function of TCA/Mud used to determine the dose. Laboratory pressure filtration tests were on cake compressibility and cake resistance. of TCA and GLFA effects process conditions with TCA was produced under a variety of adverse XRD and XRF, the resulting product assessed for filtration efficiency. with filtration results. SEM analysis of the TCA produced correlated 4:15 PM Alumina: The Ouro Control of Calcium Contamination in Preto Experience project), the global architecture of the system and the project struc- the project system and of the architecture the global project), ture. Break 3:40 PM 3:50 PM Enhance Filtra- Aluminate Use to of Tricalcium Optimization Bayer Process tion in the

WEDNESDAY PM 155 Manufacture Increasing PitchYield byThermal SoakingofTar forPitch 2:55 PM petroleum pitchwillbediscussed. dures foridentifyingacceptable petroleum componentsofcoaltar/ performance evaluationsofcoal tar petroleumpitches.Also,proce- potential environmentaladvantages ofcoaltarpetroleumpitches,and leum binderpitchesincludingthe future ofcoaltarpitchsupplies,the This paperwilldiscusstherationalebehinddevelopingcoaltar/petro- driven byrawmaterialavailabilityandenvironmentalregulations. binder. Inthefutureevaluationofpetroleummaterialmaybe tions weredrivenbythepotentialofproducingamoreeconomical evaluations producedlessthandesirableresults.Mostoftheseevalua- use ofpetroleumderivedbindersforproducinganodes.Manythese Overtheyearsaluminumindustryhasevaluatedpotential pany, P.O. Box911, Catlettsburg, KY41129 USA Pittsburgh, PA 15238-1362USA; Melvin D.Kiser Developing CoalTar/Petroleum Pitches 2:30 PM with specialemphasisonpossibleinteractionscarbonization. petroleum residues,commercialbindercoal-tarpitchesandtheirblends on thestudyofcompositionandpyrolysisbehaviorseveral different behaviorandpropertiescanbeexpected.Thispaperfocuses chemical compositionofcoal-tarandpetroleumderivativesavery peting with,bindercoal-tarpitches.However,duetothedifferent an attractiveandinterestingalternativeforreplacing,oratleastcom- binder materialsforanodesandelectrodes.Petroleumderivativesseem about exposuretocarcinogensatwork,haveledthesearchfornew reduction indemandformetallurgicalcokeandtheincreasingconcern the productionofcarbonanodesandgraphiteelectrodes.However, Coal-tarpitcheshavebeentraditionallyusedasbindermaterialsfor Escombreras, Cartagena,Murcia30350Spain Apartado 73,Oviedo33080Spain; Menendez Pitches Petroleum DerivativesasanAlternativetoBinderCoal-Tar 2:00 PM Technology CenterArdal,OvreArdalN-6882Norway Session Chair: Room: Knoxv March 15,2000 Wednesday PM Aluminium Pechiney, StJeanDeMaurienne73303France Vaagsbygd, KristiansandN-4675Norway;ChristianDreyer, Program Organizers: Sponsored by: Carbon Technology: RawMaterials Invited Panelists: "Aluminium Reduction-Wheretofromhere?" 3:40 PMPanelDiscussion- 3:20 PMBreak sented, andongoinglaboratoryexperimentsaredescribed. anode andwettedcathodetechnologies.Thesystemconceptsarepre- the electrolyte.Thesystemthusoffersadvantagesofbothinert anodic, andaluminum-wettedcathodesthataresuspendedverticallyin cept includesan“inverted”cellinwhichthelinerandbottomare that themainprocessoffgasisoxygen,notcarbonoxides.Thecon- particles. Thisallowstheuseofmetalalloyanodes.Theseareinertin the electrolytebemaintainedasaslurrywithundissolvedalumina temperature meltingcompositions.Thelowtemperaturesrequirethat smelting. Theelectrolytecomprisesfluoridesaltmixtureswithlow- : M.Perez 1 ; 1 : Instituto NacionaldelCarbon,CSIC,LaCorredorias/n, Olof Malmros 2 ; Light MetalsDivision,AluminumCommittee Trygve Foosnas,HydroAluminiumA.S., To beadvised 1 1 Koppers IndustriesInc.,1005William PittWay, ; Marcos Granda Location: OprylandConventionCenter Morten Sorlie,ElkemASAResearch, 1 Chair: NolanRichards ; StewartH.Alsop 2 Marathon AshlandPetroleumCom- 2 Repsol Petroleo,S.A.Valled de 1 ; R.Garcia ille A : Robert H.Wombles 2 ; 1 ; E.Romero Nigel R.Turner 2 ; R. 1 3 ; ; Chem., TrondheimN-7491Norway; Norway; 1 sis Characterization ofOpticalTexture inCokesbyImageAnaly- 3:20 PM sors. control anodesfabricatedwithstandardnon-thermallysoakedprecur- thermally soakedtarhadsimilarphysicalandchemicalpropertiesto mesophase. Benchscaleanodesfabricatedwithpitchesmadefrom value wereallincreased,withoutproducinganyopticallyvisible 4 to6%absolute.Toluene insolubles,quinolineinsolublesandcoking hours undernitrogenat5barpressuregaveanincreaseinpitchyieldof pitch. Typical laboratorytarthermalsoakconditionsof385ºCfor6 laboratory undernitrogenatpressurethenvacuumdistilledtoproduce distillation intopitch.Pre-treatedtarwasthermallysoakedinthe increase pitchavailabilityistothermallysoakthecoaltarpriorits thermal soakingduringthetardistillationprocess.Onetechniqueto rent practice,anodebinderpitchproducedreceivesasmallamountof dicted toexceedsupplywithinthenexttenyears.Accordingcur- ity becausethealuminiumindustrydemandforcoaltarpitchispre- Techniques toincreasetheproductionofpremiumbinderareaprior- AbstractSubmissionforTMS2000CarbonSessionProgramme Scunthorpe, NorthLincolnshireDN156URUK DN158QX UK; ited, MeridianHouse,NormanbyRd.,Scunthorpe,NorthLincolnshire 1 inversely proportional fortheNorthAmericanand MiddleEastrefin- tion temperature for theEastAsianandSouthAmerican refineriesand carboxy reactivitywasfoundto be directlyproportionaltocalcina- American andMiddleEastrefineries wasofparticularinterest.The behavior betweenEastAsianand South AmericanrefineriesandNorth reactivity. Theobserveddifferences foundinthecarboxyreactivity tween greenandcalcinedcoke properties andtheiraffectonCO2 17 differentrefinerieshaveresulted inanumberofcorrelationsbe- Examinationofmorethan180laboratorycalcinedsamplesfrom Tech. Lab.,4276SecondSt.,MuscleShoals,AL35661USA Metals Company, CarbonandEnvironmentalTech. Dept.,Smelter Roy AllanCahill Factors InfluencingtheCarboxyReactivityofCalcinedCoke 4:20 PM index. well astheresultingcoketexture,expressedintermsofamosaic process. Thecokereactivitydependsonthecatalystconcentration as and coalescenceofthemesophaseparticlesduringcarbonization the CO aluminumacetylacetonate-cokes hadnoapparenteffectonneither however, inhibitedthereactions.Additionof1wt%sulfurto the and NaFcatalyzedboththeairCO sure. TheAl aluminumfluoride, cryoliteorsodiumfluorideandcarbonizedunderpres- Highpuritycokeprecursorsaredopedwithaluminumacetylacetonate, Box 8040Vagsbygd, Kristiansand N-4675Norway ganic Chem.,Trondheim N-7491Norway; gian UniversityofScienceandTechnology, Dept.ofChem.andInor- pounds Reactivity andTexture ofCokesDopedwithAluminumCom- 3:55 PM 3:45 PMBreak industrial petroleumcokes. tor thesampleistakenfrom.Theresultsarecomparedtocalcined type (organic/inorganic),amountadded,andthepositioninreac- variation inopticaltextureisseen,dependingoftheaddedcompound compounds andcarbonizedunderpressureinthelaboratory. Alarge made ofhighpurityprecursorsdopedwithdifferentaluminium/sulphur optical domainanisotropy. Themethodhasbeenappliedtocokes a measureofopticaldomainsize;andfiberindex,whichis cokes hasbeendeveloped.Themethodoutputsmosaicindex,whichis Afullyautomaticmethodforimageanalysisofopticaltexture N-4675 Norway Tarconord A/S,Avernakke, Nyborg DK-5800Denmark; SINTEF AppliedChemistry, Inorganic Chem.,Trondheim N-7465 : Stein Rørvik 2 : northeairreactivity. Theadditionsinterferedwiththegrowth 2 Marianne Aanvik Norwegian UniversityofScienceandTechnology, Instit.of 2 O 3 (fromtheaddedaluminumacetylacetonate),Na 1 1 3 ; MarianneAanvik ; RalphE.Gehlbach Bitmac Limited,ScunthorpeWorks, DawesLn., 1 ; MortenSorlie 2 3 ; HaraldA.Øye Elkem ASAResearch,Vågsbygd 1 ; G.ScottTittle 2 gasificationreactions.AlF 2 2 ; HaraldA.Oye Elkem ASAResearch,P.O. 2 ; MortenSørlie 1 2 ; Bitmac Lim- 1 ; 1 Reynolds 1 Norwe- 3 AlF 3 3 6 : ;

WEDNESDAY PM 156 ; : 1 ; Leonard 1 Selee Corporation, 1 University of Quebec, ; 1 1 ; Joachim G. Krüger 1 ; 2 VAW Aluminium AG, Bonn, VAW ; Dawid D. Smith 3 1 RWTH Aachen, Aachen Ger- Aachen, RWTH 1 ; 3 ; Peter Waite 1 Bettina Hübschen ; Kenneth R. Butcher 1 : Kenneth R. Butcher : ; Rung Tien Bui ; Rung Tien ; Wolfgang Schneider ; Wolfgang 1 2 Selee Corporation, R&D, 700 Shepherd St., Hendersonville, 1 Alcan International Limited, P.O. Box 1250, Jonquiere, Que- Alcan International Limited, P.O. Dawid D. Smith 2 ; Foseco Aluminium, Tamworth UK; Foseco Aluminium, Tamworth 1 2 : NC 28792 USA the treatment of molten The use of chlorine as a fluxing gas in of molten salts that can aluminum usually results in the formation filters and are associated compromise the performance of downstream purpose of developing a with salt/oxide inclusion agglomerates. The and to improve salt filter was to reduce or eliminate these problems by the use of microporous Salt filtration is achieved final melt quality. salt. The theory be- media designed to selectively adsorb the molten as well as the DOE hind the development of the salt filter is presented at the Alcoa Technology sponsored performance evaluation of a unit Center. 4:15 PM of the Fluid Flow in A New Approach for the Investigation Ceramic Foam Filters Neil J. Keegan Dept. of Appl. Sci., 555 Boul. De l’Universite, Chicoutimi, Quebec, Canada; bec, Canada A two-dimensional mathematical model has been developed for representing the dynamic behavior of the filter bed. This model involves the solution of Navier-Stokes equations for the flow field and the inclusion mass fraction equations for the concentration field. All Germany The filtration efficiency of ceramic foam filters depends strongly investigate this two To on the fluid flow in the channels of the filter. new water models were used. The first one was a full scale filter box model. Tracer tests on the CFF were made to investigate the change of flow behaviour with flow rate and filter pore size. The transient point from laminar to turbulent flow could be determined by pressure drop measurements. The second water model used was a specially designed By single channel model to simulate the flow in one channel of a CFF. pulse input of a tracer, the flow behaviour could be determined quanti- It was found that flow velocity is a crucial parameter for tatively. Filtration volume decreases rapidly if filtration filtration efficiency. velocity increases thus making deposition of particles more unlikely. 4:40 PM Mathematical Model of Aluminum Filtration 2D Transient paper presents the results of an extensive experimental program con- program experimental an extensive results of presents the paper chlo- fluxing with process of the and optimize to characterize ducted of an the utilization program is of the features of the unique rine. One 25,000 process. A fluxing to control the monitor emissions on-line Metals complex at the Reynolds furnace in the casting pound melting trials. The was used in these Research Center Company Corporate In-line in the bottom for fluxing. with porous plugs furnace is tilting spinning the furnace with an efficient was also done outside gas fluxing together with study, results obtained in this The experimental degasser. a detailed Reynolds to construct analysis, have allowed a theoretical removal process. This understanding allows model of the alkali metal chlorine consumption and chloride emis- one to significantly reduce refining process. sions during the metal 3:20 PM to Detect Salts in Molten Aluminum Evaluation of a Probe Alloys Hendersonville, NC 28792 USA Eng., 700 Shepherd St., in the degassing of molten aluminum usually The use of choloine of molten salts that compromise the perfor- results in the formation filters and results in sporadic releases of inclu- mance of downstream the development and evaluation of a real sions. This paper describes the presence of liquid salts in molten time salt probe that detects discussed as well as the aluminum. The theory behind the probe is production environ- evaluation of the probes in experimental and ments. 3:45 PM Break 3:50 PM Liquid Salts from Evaluation of a Filter Developed to Remove Molten Aluminum Aubrey many; Duygu Kocaefe ; ; 1 1 Reynolds 1 ; 2 Martin Taylor : Eddie M. Williams : ; Geoffrey K. Sigworth ; Geoffrey 1 GKS Engineering Services, 116 Derby 1 ; 1 STAS, 1846 Outarde, Chicoutimi, Quebec STAS, 1 Paul Crepeau, General Motors Paul Crepeau, General Location: Opryland Convention Center Location: Opryland ; 2 A.N.O. Southwire 2 David V. Neff, Metallics Systems Company Metallics Systems Neff, David V. ; Sander A. Levy Light Metals Division, Aluminum Committee Division, Aluminum Light Metals 1 GKS Engineering Services, 116 Derby St., Johnstown, GKS Engineering Services, 116 2 Geoffrey K. Sigworth : Metals Company, Corp. Tech. Ctr., 13203 N. Enon Church Rd., Chester, Ctr., Corp. Tech. Metals Company, 23834 USA; VA Ron W. McCarthy Ron W. 15905 USA PA The alkali metals Na, and to a lesser extent Li and Ca, are found as undesirable impurities in aluminum. These must be removed to ex- traditional way The tremely low levels for acceptable product quality. to refine the metal is to flux with chlorine and an inert gas. This process is poorly understood, however, and excessive chlorine con- This sumption and chloride emissions to the atmosphere may occur. G7K1H1 Canada; The Alcan Compact Trough Degasser (ACD) has been operating in The Alcan Compact Trough Degasser (ACD) years in North America, many plants continuously for more than five only within Alcan instal- Europe, Australia, South Africa and Asia, not experience was with lations but also in non-Alcan plants. The early experience has been can stock production (ingots), but more recent with billets, remelt ingots and continuous casting. This paper updates performance results, not only for degassing but paying particular attention to alkaline removal and inclusion removal in non-Alcan plants. Extensive testing by various companies, sampled from the more than 40 plants now using the ACD, has shown that up to 90% alkaline removal is possible and up to 85% inclusion removal has also been achieved. Conditions are described under which these removal rates are obtained using both LimCa and PodFa results for inclusion removal and Alscan for hydrogen removal. These conditions include the relative humidity in the cast house, the type of alloys degassed, the temperature of the molten alloys and the quantities of chlorine and argon gas. 2:55 PM Aluminum Removal of Alkali Metals From St., Johnstown, PA 15905 USA 15905 St., Johnstown, PA pressure to improve metal The aluminum industry is under continual while at the same time reduce costs. It is also necessary to quality, The only way to do reduce undesirable emissions to the environment. In this review a theo- this is through continual process optimization. alkali metals by retical analysis is given for the removal of dissolved for ways to improve the chlorine fluxing, and suggestions are made of chlorine process. Particular emphasis is placed on minimization use. 2:30 PM Degasser (ACD) The Alcan Compact Trough Schoonevelt Hugo Van 2:00 PM Introductory Remarks 2:05 PM 2: Removal of Alkali Gas Fluxing of Molten Aluminum, Part Metals Sponsored by: Sponsored Cast Shop Technology: Fluxing and Fluxing Technology: Cast Shop Filtration Program Organizers: Wednesday PMWednesday March 15, 2000 Mississippi Room: eries examined. Parameters such as%S,%N evolved, impurities, etc. impurities, evolved, such as%S,%N Parameters examined. eries results The this phenomenon. to explain an attempt examined in were discussed. study are of this Group, Pontiac, MI 48340-2920 Corporation, GM Powertrain Commonwealth Aluminum USA; James N. O’Donnell, of Engineering, Louisville, KY Corporation, Department 40202-2823 USA Session Chair: USA Solon, OH 44139-2717 LP,

WEDNESDAY PM 157 S. Srivatsan Fatigue Characteristics ofAluminumAlloy2524 Influence ofTest Temperature onCyclicStress Responseand 2:25 PM on loadtransfermechanismswas discussed. amplitude alongtheinterface.The effectofinterfacialwearbehavior length andnumberoffatiguecycles wasassessedusingmeanroughness face relativeslidinglength.Therelation betweentheinterfacesliding cycles. Thewearbehaviorshowedstronglydependenceontheinter- weared interfacewasfoundtodecreasewiththeincreaseoffatigue fracture endandthemeanamplitudeofasperityroughnessat the Abrasive wearduetofrictionalslidingwasobservedatnearthefiber observed andevaluatedquantitativelyusingatomicforcemicroscope. posite. Thepost-fatiguemorphologyofthefiber-matrixinterfacewas unnotched inSiC(SCS-6)fiber-reinforcedTi-15-3alloymatrixcom- damage mechanismoccurringduringisothermalfatiguetestof an ite damageevolution.Thepresentstudyfocusedontheinterface in fiber-reinforcedcompositesplaysanimportantrolethecompos- Itiswell-knownthattheprogressofinterfacedebondingandsliding 106-8558 Japan Tokyo, Instit.ofIndustrial Sci., 7-55-1,Roppongi,Minato-ku,Tokyo Sengen, Tsukuba-shi, Ibaraki-ken305-0047Japan; 1 Yoshihisa Tanaka tigue Test inSiCFiber-Reinforced Ti-15-3 MatrixComposite Interface DamageMechanismduringHighTemperature Fa- 2:00 PM Japan H. Yaguchi, KobeSteelLimited,Met.Rsch.Labs.,Eng.Div., Dept. ofMatls.Sci.&Eng.,Knoxville,TN37996-2200USA; Session Chairs: March 15,2000 Wednesday PM Engineering, Urbana,IL61801USA University ofIllinois,DepartmentMaterialsScienceand Engineering, Tempe, AZ85287-6106USA;J.K.Shang, University, Department ofMechanicalandAerospace Philadelphia, PA 19104USA;PedroD.Peralta,ArizonaState vania, DepartmentofMaterialsScienceandEngineering, Ontario Canada;CharlesMcMahon,UniversityofPennsyl- Department ofMetalsandMaterialsScience,Toronto, Program Organizers: Mechanical BehaviorofMaterials Critical Technology Sector, StructuralMaterialsDivision,Jt. Sponsored by: mental Fatigue Professor CampbellLaird:Environ- Materials; ASymposiuminHonorof Cyclic DeformationandFatigueof segregation onthefilterbehaviorwillbepresented. paper, thevariousapplicationsofmodelsuchaseffectbed to predictthetrendsobservedinindustryreasonablywell.Inthis aluminum filtrationarenotwellknown.However,themodelappears drop iscalculatedfromErgunequation.Themechanismsinvolvedin inclusion depositionasafunctionofbeddepthandtime.Thepressure accounts forthechangeofbedporosityandparticlesizewith sented asasourcetermofthemassfractionequation.Themodel into account.Theinclusiondepositionandre-entrainmentarerepre- the relevantphysicalphenomenatakingplaceinbedaretaken National ResearchInstituteforMetals,ProcessingMatl.Div., 1-2-1, 1 ; P. Magnusen 1 ASM International:MaterialsScience ; Yutaka Kagawa P. K.Liaw, TheUniversityofTennessee, Location: OprylandConventionCenter Room: CanalA 2 Zhirui Wang, UniversityofToronto, ; 1 The Universityof Akron,Dept.ofMech. 2 ; Y. -F. Liu 1 ; ChitoshiMasuda 2 The Universityof : D. Kolar 1 ; T. 1 ; : Thermal ActivationofFatigueDamage 3:15 PM ergy ResearchCorporation. contract DE-AC05-96OR22464,managedbyLockheedMartinEn- of theHighTemperature Materials LaboratoryUserProgramunder Renewable Energy, andOffice ofTransportation Technologies, aspart the U.S.DepartmentofEnergySecretaryforEfficiencyand Dr. D.DurhamandMs.M.Poatsascontractmonitors,respectively), National ScienceFoundation(DMI-9724476andEEC-9527527with will beelucidated.ResearchsupportedbyTaiwan Power Company, behavior andthedamagemechanismsresponsibleforfatiguelife can resultinashorterfatiguelifeat1,000Hz.Themicro-cracking 24 maximum stresslevel,whileat20Hz,itapproachesonlyabout23to above 100 Hz and20Hz.Atthesametime,ahighersaturation-temperature failure. Ashorterlifeofthetestspecimenshasbeenobservedat1,000 crease oftemperature,andadroptemperaturefollowingspecimen specimen temperature,asaturation-temperatureregion,anabruptin- profiles wereobservedduringfatiguetesting:aninitialincreaseofthe fatigued specimensat1,000Hzand20Hz.Fourstagesoftemperature tion systemhasbeenusedtomeasurethetemperatureprofilesof RPV steelsatdifferentfrequencies.Athermographicinfrareddetec- applied at1,000Hzand20tostudythefatiguecharacteristicsof steel isatemperedmartensite.Usinground-barspecimens,loadswere steels (SA533B1I2)at1,000Hzand20Hz.Themicrostructureofthe Fatiguebehaviorwasinvestigatedonreactorpressurevessel(RPV) wan Dept. ofMatls.Sci.andEng.,Knoxville,TN37996-2200USA; Y. Huang at 1,000Hzand20 Fatigue BehaviorandThermographyofPressure Vessel Steels 2:50 PM rationalized. strain-strain characteristics,fatigue-lifeandfracturebehaviorwillbe ing. Theinfluenceoftesttemperatureoncyclicstressresponse, fects anddislocation-microstructureinteractionsduringcyclicstrain- amplitude, concomitantresponsestress,intrinsicmicrostructuralef- competing andmutuallyinteractiveinfluencesofcyclicplasticstrain and fracturecharacteristicsofthealloywillbehighlightedinlight temperatures. Inthispresentation,thelow-cyclefatigueproperties tudes givinglessthan104cyclestofailure,andatthreedifferenttest ing, undertotalstrain-amplitudecontrol,overarangeofstrainampli- were cyclicallydeformedusingfully-reversedtension-compressionload- in theT351microstructuralcondition.Test specimensofthealloy strain low-cyclefatigueandfracturebehaviorofaluminumalloy2524, has beenmadetounderstandtheinfluenceoftesttemperatureonhigh cyclic stressandstrainamplitudecontrol.Inthisconnection,astudy mands satisfactoryperformancefromthematerialunderconditionsof space, automotiveandrelatedgroundtransportationindustriesde- Theeffectivedesignofstructuralcomponentsforuseintheaero- Alco Tech. Ctr., 100Technical Dr., AlcoaCenter, PA 15069USA Eng., Akron,OH44325-3903USA; These resultsare consistentwithadislocationmodel ofjogformation tion barriersdecreases indirectproportiontotheapplied cyclicstress. activation energyis240kJ/mole. Themagnitudeofallthreeactiva- ported fordiffusioninaluminum. Forfatiguelives>3x10 120 kJ/moleinunreinforced5086 aluminum,i.e.,intherangere- energy is86kJ/molein339aluminum/15% Kaowoolcompositesand gimes areidentified.Forfatigue lives<3x10 the intrinsicfatigueprocessisthermally activated.Two distinctre- These twoeffectsareseparatedforthefirsttime,anditisshownthat ture andtheintrinsictemperaturedependenceoffatigueprocess. from acombinationofthermallyinducedchangesinthemicrostruc- Theeffectoftemperatureonthefatiguealuminumalloysresults Livermore, CAUSA MI 48090-9055USA; R. Lesuer Village, Lungtan,Taiwan 325; Nuclear Energy Research,P.O. Box3-14,1000Wenhua Rd.,Chiaan Ridge NationalLaboratory, OakRidge,TN37831USA; ° C. Amuchgreatertemperaturegeneratedat1,000Hzthan20 2 3 ; CholK.Syn ; R.C.Kuo ° C canbereachedat1,000Hz,dependingontheapplied 3 ; J.G.Huang : 2 ; 2 Lawrence LivermoreNationalLaboratory, P. K.Liaw 1 GM, R&DCtr., 30500MoundRd.,Warren, 4 Taiwan PowerCompany, Taipei, Tai- 1 ; H.Wang 2 4 Aluminum CompanyofAmerica, ; 1 The UniversityofTennessee, : William J.Baxter 2 6 ; L.Jiang cycles,theactivation 1 ; B.Yang 6 3 cycles,the Institute of 1 ; Donald 2 Oak 1 ; J.

WEDNESDAY PM 158 ; : 1 ; Feng 1 The Ohio 1 ; H. Mitani ; 1 1 H. Yaguchi GE Aircraft Engines, 1 2 Masuo Hagiwara : : Tokyo Institute of Technology, Institute Tokyo 3 ; Hamish L. Fraser AlNb-based alloys are potential 2 2 Kobe Steel Limited, Matls. Rsch. Matls. Steel Limited, Kobe 1 ; 3 Mark E. Schlesinger, University of University Mark E. Schlesinger, National Research Institute for Metals, The 1 Location: Opryland Convention Center ; 1 ; M. Kato C), some alloys in this system show a substantial 3 ; Richard Grylls AlNb-Based Alloys ° 1 2 Joseph W. Newkirk, University of Missouri- Joseph W. TMS alloy and is said to have the best balance of tensile, alloy and is said to have the best balance of β ; T. Fujii ; T. 2 Kobe Steel Limited, Eng. Div.; Limited, Eng. Div.; Kobe Steel 2 ; Satoshi Emura 1 State University, Dept. of Matls. Sci. and Eng., 477 Watts Hall, 2041 Dept. of Matls. Sci. and Eng., 477 Watts State University, College Rd., Columbus, OH 43210 USA; MB5, Cincinnati, OH 45215 USA Neumann Way, Advanced jet engine design requires new structural materials with adequate toughness and lower density, higher temperature capability, system which exhib- A candidate system is the Nb-Ti-Al producibility. its good high temperature properties as well as room temperature ductility in certain compositional ranges. However, at intermediate temperatures (<1000 loss of ductility and tend to be embrittled. Thus, recent research conducted on the tensile behavior [Hou, 1994] and discontinuous yield behavior [Perungulam, 1997] of some alloys in this system shows 2:00 PM of Properties and Creep Mo and V on Tensile of W, Effect Orthorhombic Ti Ibaraki 305-0047 Japan Third Rsch. Grp., 1-2-1 Sengen, Tsukuba, The orthorhombic (O-phase) Ti Ti-22Al-27Nb is high temperature materials for aircraft applications. a two phase O+ to increase the me- creep and fracture toughness properties. In order chanical properties further, transition elements (W Mo and V) were added to this alloy by substituting them for a part of Nb in an amount Six new alloys containing different depending on their beta stability. Mo or V were prepared, and their microstructures, amount of W, tensile and creep properties were investigated. The test results showed that W is effective on increasing the high temperature tensile strength and creep resistance. 2:20 PM The O(rthorhombic)-Phase Embrittlement in Nb-Ti-Al Alloys 4:55 PM 4:55 Tubes Transfer Heat in Aluminum Evaluation Damage Fatigue Thickness Cell Dislocation by Measuring K. Nagano Labs.; and Eng. Matls. Dept. of Innovative formation in damage prior to crack to evaluate fatigue A method stresses undergo cyclic thermal transfer tubes which aluminum heat dislocation fatigue region where In the low cycle has been developed. found to be measurement has been cell wall thickness cells are formed, fatigue damage both in laboratory experi- a useful method to evaluate devices. The validity of the cell wall thickness ments and in practical fatigue damage evaluation will be discussed. measurement method on Intermetallics II: General Abstracts: Aluminides Sponsored by: Organizers: Program of Metallurgical Engineering, Rolla, Missouri, Department Reynolds Metals Tabereaux, MO 65409-0001 USA; Alton T. Muscle Shoals, Laboratory, Smelter Technology Company, Alamos National AL 35661-1258 USA; Dan J. Thoma, Los Los Alamos, Materials Science and Technology, Laboratory, Lawrence NM 87545-0001 USA; Patrice E.A. Turchi, Materials Science and Livermore National Laboratory, Division, Livermore, CA 94551 USA Technology Wednesday PMMarch 15, 2000 A/B Room: Johnson Session Chair: USA Rolla, Dept. of Met. Eng., Rolla, MO 65409-0340 Tang Sundar Amancherla ; ; 2 1 m), √ (at.%). 22 .5 , under both University of 4 Be 1 ; S. J. Pawel 1 10 ; 2 Ni ~18-59 MPa Ic 12.5 : James T. Broome : James T. Cu ; B. Yang 1 13.8 ; K. Farrel Ti 2 41.2 University of California, Dept. 1 ; ; L. Jiang 1 1 ; G. T. Yahr ; G. T. 2 ; D. Fielden 1 ; R. O. Ritchie 1 ; J. R. DiStefano 2 ; P. K. Liaw ; P. 2 V. Schroeder V. Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA Oak Ridge National Laboratory, 2 : and fatigue-crack growth properties in room air that are comparable to ductile crystalline metals. Despite such promising mechanical properties, in an aerated 0.5 M NaCl solution, we find that fatigue-crack by 2-3 orders of magnitude. In the growth rates increase dramatically, increase in fatigue-crack growth we examine this large present study, rates with the specific goal of identifying the role of environment in has been this end, fatigue testing the fatigue-crack growth process. To performed in a number of environments, including de-aerated 0.5 M NaCl, 0.05 M NaCl, de-ionized water, and 0.5 M NaCIO open circuit and potential control; in addition, static load testing has been performed in an aerated 0.5 M NaCl solution. It is found that the effect of sodium chloride solution depends on an anodic process that is active under cyclic and static loads (stress-corrosion cracking), and depends on the concentration of the solution and the identity of anions in the solution. of Matls. Sci. and Mineral Eng., Berkeley, CA 94720-1760 USA of Matls. Sci. and Mineral Eng., Berkeley, a number of strongly glass-forming metallic alloys have Recently, been found; one commercial alloys is Zr Our initial investigations of this Zr-based metal revealed that it has high tensile strength (~1.9 GPa), good toughness (K The Spallation Neutron Source (SNS) is an accelerator-based instru- The Spallation Neutron beams of neutrons by bombarding a mercury ment that provides pulsed of 1-GeV protons. The facility is being target with intense beams in needs of the neutron scattering community designed to fulfill the Mercury has been selected as a next century. the U. S. well into the as type 316 LN stainless steel has been chosen possible SNS target, and material. Fatigue behavior of 316 stainless a possible target container in an air as well as mercury environment. The steel will be investigated 1 to fatigue loading in the frequency range of samples will be subjected Hz tests will be performed in a specially Hz to 1000 Hz. The 1000 soundproof room. It will be de- constructed, temperature-controlled, mercury environment termined whether or not the frequency and and crack growth have a great influence on the fatigue crack initiation steel. The ability to run rate behavior of the cyclically-loaded stainless time and allow for the tests at 1000 Hz will greatly reduce testing 109 cycles, which takes development of pertinent fatigue results at of liquid metal about eleven and a half days. The possibility by comparing the re- embrittlement (LME) will also be investigated will be one of two sults in air and mercury environments. The samples rod with a gauge section. types. The first type, for uniaxial testing, is a the loading condi- The second type is a disc, which is used to simulate have been performed tion of target container materials. Calculations achieve bending stresses to determine the displacement necessary to at 1000 Hz. The fatigue to exceed the yield strength of the samples of 316 stainless steel results will be discussed in light of the application Research sponsored as a target container material in the SNS system. of Basic Energy Sciences, by the Division of Materials Sciences, Office DE-AC05-96OR22464 under Contract U.S. Department of Energy, In addition, J. B. with Lockheed Martin Energy Research Corporation. K. L. are very grateful to the support of the Oak Ridge National and P. 4500007186, to the Laboratory under the contract number, LMER the sup- would also like to acknowledge We University of Tennessee. and EEC- port of the National Science Foundation [DMI-9724476 D. Durham and Ms. M. Routs as program managers, 9527527 with Dr. respectively]. 4:30 PM Corrosion Fatigue Behavior of a Zr-Based Bulk Amorphous Metal Tennessee, Dept. of Matls. Sci. and Eng., Knoxville, TN 37996-2200 Dept. of Matls. Sci. and Eng., Knoxville, TN Tennessee, USA; at low cyclic stresses and the diffusion assisted motion of jogs at high of jogs assisted motion diffusion and the cyclic stresses at low loop to dislocation correspond volumes activation stresses. The cyclic 30 nm. of 10 to lengths Break 3:40 PM 4:05 PM of Spal- on Fatigue Behavior Mercury Environment Influence of Materials (SNS) Target Source lation Neutron Strizak J. P. L. K. Mansur

WEDNESDAY PM 159 iron. Supersaturated aluminum,titaniumandcarbon wereprecipitated mechanical alloying, resultingintheextensionof solidsolubilityin phase identification.Supersaturated ironsolidsolutionwasobtainedby evaluated metallographically, bySEM-EDXanalysisandXRD for same compositionweresintered aftermixing.Allthealloyswere examine theeffectofmechanical alloying,thespecimenswith which istheratioinTiC formedduringin-situmeltingprocess.To powder wereused.Theratioof titaniumtocarbonwas51.6:48.4, aluminum powder,99.9wt%titaniumpowderandgraphite after sintering.Asforrawmaterials99wt%ironpowder,99.9wt% neous distributionofTiCparticlesintheFe chanical alloyingandpulsedischargesinteringprocesses.Ahomoge- factured byin-situreactionbetweentitaniumandcarbonduringme- Titaniumcarbidereinforcedironaluminidecompositesweremanu- Miyagi-ken 983-8551Japan Institute, Matls.Sys.Div., 4-2-1,Nigatake,Miyagino-ku,Sendai, Hashimoto cess posites ManufacturedbyMA-PulseDischargeSinteringPro- In-Situ TiCReinforcedFe-28at%AlIntermetallicBasedCom- 3:20 PM ment ofEnergygrantDE-FG02-87ER4311. by NationalScienceFoundationgrantDMR9973977andU.S.Depart- have beenusedtoconfirmthissuggestion.Thisresearchwassupported tals atavarietyoftemperaturesfollowedbyannealingintheDSC principally inAPBtubes,arethesource.Tensile testsonsinglecrys- ferromagnetic behaviorsuggeststhatantiphaseboundaries(APBs), unrolled singlecrystal.Analysisofthepossiblecontributionsto nealed specimenstillshowedalargermagneticsusceptibilitythanthe perature exothermicpeak,butattemperaturesbelow225Kthean- ferromagnetism disappeareduponannealingabovethelowest-tem- from paramagnetismtoferromagnetism.Atroomtemperature,the exothermic peakswereobserved.Thecoldrollinginducedatransition min SinglecrystalsofFe-40Alwerecoldrolled,andthenheatedat10K ramics Div., OakRidge, TN37831USA 03755-8000 USA; College, ThayerSchoolofEng.,8000CummingsHall,Hanover,NH in FeAl The Strain-InducedParamagnetictoFerromagnetic Transition 3:00 PM which correlatedwithincreasingamountsofthe showed increasedstrengthwithagingtemperatureandtime, significant effectofagingonthestrength.The25Tiand10Tialloys single phase(B2structure)forallheattreatments,andtherewasno harder Nb solution strengtheningbytheNb,butincreasedpresenceof all conditionsastheNbcontentincreased.Thisisattributedtosolid ning electronmicroscopy. Therewasamarkedincreaseinstrengthfor 1100 rolled condition.Specimenswereagedfor10or100hat600,900and alloys wereintheas-castcondition,and40Tialloywashot- alloys intheinitialconditionsandafteraging.The10Ti25Ti 10 Compressiontestshavebeenconductedat900 Tennessee, Matls.Sci.andEng.,Knoxville,TN37996USA Dah-Liang Guan Nb-15 at.%Al-10at%Ti,-25Tiand-40Alloys Microstructure andMechanicalPropertiesofAs-CastAged 2:40 PM relationship betweenmicrostructureandpropertieswillbediscussed. have beencharacterizedusingSEMandTEMtechniques,the and theformationofO-phase.Samplesdeformedfractured whether ornotthereisafunctionaldependencebetweenembrittlement been heat-treatedatvariousintermediatetemperaturestodetermine structure. Tensile testshavebeenconductedonspecimenswhich phase hasastoichiometryofTi which formsatintermediatetemperaturesinthesealloys.TheO- temperatures. ThisembrilltlementmaybeattributedtotheO-phase strong evidenceforasignificantdecreaseinductilityatintermediate -4 s -1 : ° inadifferentialscanningcalorimeter(DSC),whereuponthree -1 C. Themicrostructureswerecharacterizedbyopticalandscan- forNb-15at.%Al-10Ti,-25Tiand-40 Se HyunKo : 3 1 Ian Baker Al ; Toshihiko Abe δ phasealsocontributed.The40Tialloyremaineda 1 ; Charlie R.Brooks 2 Oak RidgeNationalLaboratory, MetalsandCe- 1 ; BongGyuPark 1 ; Y. Yang 1 ; 1 Tohoku NationalIndustrialResearch 2 1 AlNb withtheorthorhombiccrystal ; D.Wu 1 ; PeterK.Liaw 1 ; Yong HoPark 1 ; P. Martin 3 Al matrixwasachieved δ ° C atastrainrateof phase. 1 ; 2 ; 1 University of 1 Dartmouth 1 ; Hitoshi : Aluminides in UndercooledandRapidlyQuenchedGammaTitanium The Effect ofTernary AdditionsonSolidStateTransformations 4:30 PM+ the lowesttensilepropertiesatroomtemperature. boundary underthetensileloadsothatjoiningcomponentexhibits nent ofcoarsefulllamellarmaterialstrendstooccurinthejoining tion onthejoiningsurfaces.Thefracturefailureofcompo- exist inthejoiningboundaryduetodifficultyofplasticdeforma- duplex microstructureformsonthejoiningboundary. Remainingholes the joiningboundaryfortwosolid-stateprocesses.Thefine used asacouplecomponents,therecrystallizationwouldtakeplaceon as-cast TiAlbasedalloywithcoarsefulllamellarmicrostructurewas nificantly affectsthejoiningpropertyofTiAlbasedalloys.When were measured.Test resultsshowthattheoriginalmicrostructuresig- properties ofthejoinedcomponentmaterialsatroomtemperature Hot-press FurnaceandThermal-imitationMachine.Themechanical tion/diffusion joiningprocesseshasbeeninvestigatedusingVacuum microstructures forthehot-press/diffusionandsuperplastic-deforma- Thesolid-statejoiningbehaviorofTiAlbasedalloyswithvarious der Metallu.Rsch.Instit.,Changsha,Hunan410083PRC TN 37928-2200USA; 1 ous Microstructures Solid-State JoiningBehaviorofTiAl BasedAlloyswithVari- 4:10 PM 3:40 PMBreak nism ofin-situcompositeswillbepresented. to Fe that theB2orderedphaseisformed intheTi-Al-Mosystem. ray diffractionandelectron-probemicroanalysis.Theresultsshow ined byopticalandscanningelectronmicroscopy, andanalyzedby X- able electrodearcfurnace.Theirsolidificationstructureswereexam- position wasinvestigated.Thealloyswerepreparedinanon-consum- the ternaryphasediagramclosetoTi composition, isnotwellestablished.Inthepresentworkregion of superalloys. However,itsrangeofexistence,bothintemperatureand ture) hasbeenofrecentinterestasacomponentrefractory-based Thehigh-temperatureTi Aires 1429Argentina Energía Atómica, Dept.deMateriales,Av. delLibertador8250,Buenos Eduardo E.Vicente Solidification StructuresofTi-Al-MoAlloys 4:50 PM atom. pendent uponthedegreeofundercoolingandtypeternary undercoolings, theamountofmassivetransformationproductisde- Although themassivetransformationisobservedinallalloysfor phase. Thelamellartwo-phasemicrostructureiscompletelysuppressed. ture, whichtransformsinamassivefashiontothetetragonalgamma alloys, rapidsolidificationproducesanequiaxedhexagonalalphastruc- rate, athickersample,andsubsequentslowersolidstatecooling.Forall copy (TEM).Deeperundercoolingresultsinafastersolidification ning electronmicroscopy(SEM)andtransmissionmicros- microstructures wereanalyzedusingstandardopticalmicroscopy, scan- rapidly solidifiedbytwinanvilsplatquenching.Thequenched low themeltingpointbyflowingUHPheliumoverliquiddrop,and are electromagneticallylevitated,inductionmelted,undercooledbe- transformation kineticsforeachternaryalloy. Samples(0.47g Ti Microstructuralanalysisofundercooledandrapidlysolidified Highland, Nashville,TN37212USA H. Hofmeister The UniversityofTennessee, Matls.Sci.andEng.Dept.,Knoxville, 50at% 3 Al Al andTiCinsintering.Theformationproceduremecha- 48at% X : TimothyMontgomeryMiller 2at% 1 ; (X=Cr,Nb,Mo)revealsdifferentsolidstatephase 1 Vanderbilt University, Matls.Sci.andEng.,24th 1 ; GerardoH.Rubiolo : 2 Central SouthUniversityofTechnology, Pow- Yuehui He 2 AlMo intermetalliccompound(B2struc- 1 ; PeterK.Liaw 2 1 AlMo stoichiometriccom- ; 1 ; JamesWittig 1 Comisión Nacionalde : PaulaR.Alonso 1 ; Baiyun Huang 1 ; William ± 0.04g) 1 2 ; ;

WEDNESDAY PM 160 , O 2+ 2 The 2 Arash Meura 1 C with 2 Fe ° - : ; 2 , 50 Northeastern 2 1 Menad Nour- + 2 e O + ½ O 2 3+ ; : 1 +H 2+ O, Anode (Pb-Ag): H 2 = Mn or bioleaching. It has been +Fe 2 ; André Van Lierde ; André Van + 2H ; Zhitong Sui 1 O 1 2 3+ , H 2 + 2 H 2 + 2 Fe 2+ Luleå University of Technology, Dept. of Luleå University of Technology, Mn 1 + ; Taiping Lou ; Taiping 1 Philippe Henry ; 1 : + 4 H , Global: MnO - 2+ is effectively leached by electrogenerated ferrous Eramet Marietta Inc., P.O. Box 299, Marietta, OH Box P.O. Eramet Marietta Inc., 2 1 pulp) circulates upward in the expanded mesh cath- Yuhai Li Yuhai 2 under strict control of oxidation reduction potential, under strict control of 2 ; : 1 + 2 e + 2 Fe + 2 from pyrolusite ore leaching residues loaded with Fe, Al, Ni, from pyrolusite ore leaching residues loaded ; Bo Björkman 2 Cath. University of Louvain-la-Neuve, Place Ste Barbe 2, Cath. University of Louvain-la-Neuve, Place 1 2 + 2H are produced by smelting V-Ti bearing magnetite every year at 2 2 Bulk: MnO ½ O high faradic yield (> 95%) and low power consumption. (3.2 kWh/kg Mn). New applications like the treatment of spent batteries, polluted soils and spent catalysts are now investigated at a laboratory and mini- pilot scale. 4:40 PM Blast Component from for Recovery of Titanium New Technique Furnace Slag Louvain-la-Neuve 1348 Belgium for the recovery A novel electrochemical cell has been developed of MnO considered as an alterna- Co and Si impurities. This new process can be tive to the traditional methods: SO ions. The chemical reactions are: Cathode (inox): 2 Fe catholyte (MnO ode separated from the sulphuric acid solution anolyte by a diaphragm potential low which shows high mechanical resistance, low porosity, drop, and reasonable cost. Laboratory and mini-pilot tests has led to the construction of an operating pilot plant (100 kg residue/hr) able to leach more than 95% of Mn, Ni, Co at 1000-1500 A/m Shenyang Box 119, School of Matls. and Metallu., P.O. University, 110006 PRC More than 3 million tons of blast furnace slag containing about 25% TiO these wastes is a rotary hearth furnace (RHF). To date four plants have four plants date To furnace (RHF). rotary hearth wastes is a these for a fines and one iron ore dusts, one for minimill two for been built, been particularly None have waste oxides. integrated fines and mix of those operations, and critiques reviews This paper to date. successful efforts to looks back at previous pro posed systems, analyses other the long term potential service, and evaluates in similar utilize RHF’s units. performance of these for successful 3:00 PM of Electro- Manganese Usage Acid, Ammonia and Decreasing by Recycling MOR Fume lytic Manganese Production M. Kasaaian 45750 USA source for production of electrolytic man- The current manganese plant is a special slag from high carbon ganese at Marietta operation. A new process has been developed ferromanganese furnace refining of high carbon ferromanganese. The which uses fume from the recycle into the submerged arc furnaces. In fume was very hard to The use of the has been used advantageously. new process the fume of of manganese and reduces the use fume increases the recovery the The new process is based on leaching sulfuric acid and ammonia. fume with SO and removal of Si from the process solution. removing Fe by oxidation 3:25 PM Break 3:50 PM Scrap Characterization of Electric and Electronic reddine Process Metallu., Luleå SE-971 Sweden mixtures with Electric and electronic scraps are heterogeneous to or mixed with various mainly copper, aluminium, and iron attached of precious small amounts types of plastics and ceramics. Typically, electric and elec- metals are incorporated in these mixtures. Today, problematic fraction in tronic scraps constitute an environmentally have been in- waste disposal. Their physico-chemical characteristics infrared spectroscopy, vestigated through chemical, x-ray diffraction, scanning electron microscopy and thermal analyses. 4:15 PM Residues by an Elec- Recycling of Manganese from Industrial Leaching trochemical Minckelers 1, Louvain-la-Neuve 1348 Bel- RD, Voie Technologies, gium; prove to be a more eco- observed to proceed fairly rapidly and could nomically viable process, as well as being more environmentally acceptable. Electrochemical characterisation and kinetic studies have shown that MnO Christina : L.M. Southwick 1 ; 1 Larry M. Southwick : Guy Fredrickson, Reynolds Metals Guy Fredrickson, Room: Canal C Convention Center Location: Opryland Gerrit H. Nijhof, Nijhof Consultancy, 2102 Consultancy, Gerrit H. Nijhof, Nijhof Mefos, New Tech. Dept., P.O. Box 812, Luleå SE- Box 812, Dept., P.O. Mefos, New Tech. Extraction & Processing Division, Light & Processing Division, Extraction 1 ; 1 & Associates, 992 Marion Ave., Ste. 306, Cincinnati, OH 45229 USA & Associates, 992 Marion Ave., There is mounting interest in recovering and recycling iron units from steel mill wastes. Materials being utilized as feeds include minimill hazardous waste), electric arc furnace dust (which is an EPA-classified and various dusts and sludges generated by the blast furnaces, BOF’s other units in integrated mills, as well as iron ore fines produced during the shipment of iron ore or taconite pellets. The interest is driven by (i) the increasing need for quality iron units, (ii) the potential decreasing scrap supply and the desire to find suitable alternatives, and (iii) current and potential future regulations relating to these wastes. At present, the most popular system to produce quality iron units from Viklund-White 97125 Sweden the disposal of zinc used The potential environmental impacts of Cycle Assessment (LCA), for galvanizing steel have, by the use of Life recycling routes been compared to recycling. A number of hypothetical dust treatment pro- were composed involving three different EAF kiln, DC-furnace, and Ezinex, as well as scrap dezincing. cesses, Waelz galvanizing steel clearly The study shows that recycling of zinc used for resources. However, has environmental benefits in that it saves zinc the potential impact on zinc recovery does not necessarily decrease of these two impact global warming and acidification. The magnitude and type of primary categories is tightly correlated with the amount consumption in the energy consumed in a process. The high electricity the highest impact on dezincing process resulted in that this route has Potential as well as Acidification Potential. The ma- Global Warming of primary zinc from jor part of the energy required for the production in the reduction primary as well as from secondary sources is consumed theoretically possible of ZnO to Zn. The consequence is that the materials is savings in primary energy by recycling zinc-containing relatively small. The impact categories land use and waste generation of but most likely the evaluation are not considered in this study, impacts such would further increase the potential environmental impact of the landfill alternative. The results also show that the location of an electricity-intensive process highly affects the potential environmental impact. Comparing process and material alternatives in LCA studies where branch average data is used is therefore considerably more intricate than when LCA is used within a company. 2:35 PM Use of Rotary Hearth Furnaces for the Recovery and Recycling Has An Idea Whose Time of Iron Units from Steel Mill Wastes: Come, or Will Never Come? 2:00 PM Introductions and Opening Comments 2:10 PM for the Environmen- The Use of Life Cycle Assessment (LCA) Steel tal Evaluation of the Recycling of Galvanized Sponsored by: Sponsored General Recycling of Materials: Topics of Materials: Recycling General and Heavy Metals to Ferrous Related Recycling Recycling Committee Metals Division, Program Organizers: PM Wednesday Company, Smelter Technology Laboratory, Muscle Shoals, Laboratory, Smelter Technology Company, OH Toledo, Accorsi, Daimler Chrysler, AL 35661 USA; Ilaria 43606 USA March 15, 2000 Session Chairs: Netherlands; Xiangwen Wang, KN Heemstede, The Lab., Muscle Smelter Tech. Reynolds Metals Company, Shoals, AL 35661 USA

WEDNESDAY PM 161 Iliija B.Ilic Hydrometallurgical RecyclingofNickel-Cadmium Batteries 5:55 PM covery ofzinc. ducted todeterminetheappropriate leachingconditionsforthere- mine thephasespresent.Thebatch laboratoryexperimentswerecon- duced wascharacterizedbyXRD and AAspectrophotometrytodeter- ies dismantlingbymineralprocessingtechniques,thematerialpro- results ofleachingtestsusingsulfuricacidastheleachate.Afterbatter- the characterizationofspentalkallinebatteriesandexperimental an efficientmethodforrecoveringsuchmetals.Thispaperdiscusses The processingofspentbatteriesbyhydrometallurgicaltechniques is economic advantageofrecoveringmetalssuchasCd,Hg,Pb,andZn. have beenproposedforrecyclingspentbatterieswhichalso the teries havebeendiscussedintheliteratureforyears.Sometechniques environmental effectscausedbytheimproperdisposalofspentbat- waste industriallandfills(forbatteriesfromsources).The sanitary landfills(forbatteriesfromdomesticsources)andhazardous CurrentlyinBrazil,thefinaldisposalofspentbatteriesincludes Av. Prof.MelloMoraes,2463,SaoPaulo-SP05508-900Brazil Tenorio teries Hydrometallurgical RoutesforRecyclingofUsedAlkalineBat- 5:30 PM determined. and Cosalts.Foreachoperationtheoperativeconditionhavebeen tation ofNi,CoandFefinalsolventextractionondissolvedNi cal mainstepsare:acidicleaching,R.Eseparation,multistageprecipi- metallurgical processtorecoverNi,Co,andRE.Thehydrometallurgi- and activemasscomponentsthataresubsequentlytreatedbyahydro- original crushingandelutriationtreatmenttoseparateplastic,metallics, vidual cellsandplasticpowerpacksincludesasbasicstepsan based ondifferentchemistries.Theprocessisabletotreatbothindi- Italian territory, togetherwithotherindustrialandportablebatteries technology, isabletorecyclewaste Ni-MH batteriescollectedinthe diate products.AnewplantlocatedinSouthItaly, designedafterthis to recoverNickel,andCobaltsalableproductsrareearthsinterme- oped acombinationofmechanicalandhydrometallurgicalprocessing Rome, Texeco EngineeringS.r.l., andMO.SMO.DE.S.a.s.havedevel- improve thefeasibilityofrecyclingprocess.TheUniversity pact associatedtothesewastes,whilethemetalvaluesrecoverycan recycling processarethekeyfactorstopreventenvironmentalim- phones. Theorganizationofanationalcollectingsystemandcorrect growing, followingtheimpressivepenetrationrateofcellular est applicationsegments.TheItalianmarketofNiMHcellsissteadily bile communication,portablecomputersandcamcorders,arethelarg- sumer applicationsreplacingprimaryalkalinebatteries:wirelessmo- NiMHsealedcells(portablecells)aretodaywidelyusedinallcon- Italy; Roma “LaSapienza”,Dept.ICMMPM,Via Eudossiana18,Roma00184 Pilone Metal Values Recoveryfrom NiMHBatteries 5:05 PM tion andgrowthbehavioroftheperovskitephaseinslag. study oftheeffectsadditivesandheat-treatmentonprecipita- desirable tofullygrowandcoarsenthephase.Thepresentworkisa perovskite phasefromtheslagbymineraldressingmethods,itisfirst the totaltitaniumcontentofslag.Inordertoseparate concentration oftitanium,butthisphaseaccountsforlessthanhalf in thesolidifiedslag.Perovskiteisphasecontaininghighest tative analysis)showthatseveralTi-containingmineralphasesoccur alloys. Theprocess-minerologyandSEMobservation(withEDXquali- part canbeusedforproducingTiO recover theTicomponentfromslag.Theseparatedenriched has notbeeneffectivelyutilized.Itisnecessarytofindaway from theslagbytraditionalseparationtechniques.Asaresult, interfacial combinations,itisdifficulttorecovertheTicomponent phases, theveryfinegrainsize(<10 the disperseddistributionofTicomponentinvariousmineral the PanzhihuaIronandSteelCompanyworks.However,becauseof : 2 1 Mo.Smo.De. S.a.s.,Crotone,Italy; ; GiuseppeCannavale 1 Cleusa CristinaBuenoMarthadeSouza ; 1 University ofSaoPaulo,Dept.Metallu.andMatls.Eng., 1 ; Srecko R.Stopic 2 ; AlessandroPescetelli 1 ; 1 University ofBelgrade, Facultyof µ 2 pigment,andsmeltingTi-Fe m), andtheeffectsofcomplex 3 Texeco Eng.,Roma,Italy : 1 ; JorgeAlbertoSoares Carla Lupi 3 ; 1 University of 1 ; Daniela : waste reusingallcomponentmaterials. was tosafelyandproperlycollectrecyclewholeNi-Cdbattery the separationofnickelfromcadmium.Themaingoalthisstudy obtained byleachingofthewastedust.Specialattentionwaspaidto Relatively sphericalparticlesofnickelandcadmiumhavejustbeen nickel andcadmiumwereinvestigatedbyhydrometallurgicalmethods. to 373K.Experimentalconditionsofleachinganddeposition tion below333K,andwithsulfuricacidintemperaturerangefrom298 Cd batterieswasperformedwithammonia-ammoniumcarbonatesolu- 0.0154, Zn-0.0085,moisture-20.00andremainder. RecyclingofNi- contained inpercentagevalue:Ni-29.258;Cd-6.848;Co-1.743;Fe- In thisworkthewastedustobtainedinproductionofNi-Cdbatteries pellets inaretortingunit,forreuse,primarilythebatteryindustry. by specialtysteelproducers.Thecadmiumportionisconvertedto in anelectricfurnace,toproducenickelalloyspigs,usedasfeedstock blended withothernickel,chromeandironbearingwastessmelted are recycledinapyrometallurgicalprocess,wherebytheshredcells industry intheworldforalongtime.Generally, thesespentbatteries TherecyclingofNi-Cdbatteriesisabigprobleminautomobile Yugoslavia Tech. andMetallu.,Karnegijeva4,P.O. Box5303,Belgrade11000 Laboratory, Livermore,CA94550USA Session Chair: March 15,2000 Wednesday PM CA 94551-0969USA Sandia NationalLaboratories,Department8724,Livermore, ics, EastLansing,MI48824-1226USA;JohnE.Smugeresky, University, DepartmentofMaterialsScienceandMechan- NM 87545USA;MartinAllenCrimp,MichiganState Laboratory, MST-6,TheMetallurgy Group,LosAlamos, Program Organizers: Metallurgy Committee Sponsored by: tions andStructures in MaterialsScience:OtherApplica- High ResolutionElectronMicroscopy the samewayand alsoepitaxial,haveahighly regular modulated of theC11 the collapseofvacantSiplanes, leading toone-dimensionaldisorder high densityof(001)stackingfaults whichareapparentlyformedby epitaxial andhavetheC11bstructure; however,theycontainavery films formedbyreactivedeposition onSisubstratesat650 four timesthesizeofC11 formation ofacommensuratestructure withamonoclinicunitcell hombic andmonoclinicdistortions.Annealingat1250 MoSi rate structuresexceptthatthesearebasedonthetetragonalC11 have foundthatmelt-processedReSi ney-ladder” structuresbasedontheC54TiSi been foundtoexhibitincommensuratestructuresandNowotny“chim- ichiometry closetoMSi are semi-conductors,theysilicon-deficient,andhaveasto- of hexagonallayers.TheGroupVIIdisilicidesareunusualinthatthey C40 orC54structureswhichareformedbyvariousstackingsequences MostoftherefractorymetaldisilicidesaremetallicandhaveC11 MS-K765, LosAlamos,NM87545USA Amit Misra Structures inVarious MetalDisilicides HREM ofUnusualIncommensurate,ModulatedandDisordered 2:00 PM 2 structure.Theincommensurateperiodicitygivesrisetoorthor- b 1 structure.Bycomparison, (Mo,Re)Si ; 1 Los AlamosNationalLaboratory, Ctr. forMatls.Sci., Structural MaterialsDivision,Physical John E.Smugeresky, Sandia National 1.75 Location: OprylandConventionCenter Room: CanalD Diane E.Albert,LosAlamosNational (M=Mn,Tc, Re).Inaddition,MnSi b unitcell.Ontheotherhand,ReSi 2-x exhibitssimilarincommensu- : 2 unitcell.Recentlywe Terence E.Mitchell 2-x films,formedin ° C leadstothe ° 2-x C are has 2-x 1 b b ; ,

WEDNESDAY PM 162 ; 1 Leonid P. : National Cen- 2 ; B. J. Dresser 3 C, eventually lead- hydride. State Metallurgical ° 1 θ ; 1 C and de-wetting of the Carnegie Mellon Univer- 1 ° ; 1 ; J. R. Groza 2 C, and quickly reaches a plateau. C, and quickly reaches ° C. ; E. Stach ° 1 Alexey N. Lozhko ; Brajendra Mishra, Colorado School 1 Room: Jackson A/B Location: Opryland Convention Center ; Bryan Molloseau 1 Brajendra Mishra, Colorado School of Extraction & Processing Division, Waste C and 13.8 MPa. The hydride has a structure belonging C and 13.8 MPa. The hydride has a structure ° Rand Dannenberg phase and completely replaces the latter. HRTEM was used HRTEM phase and completely replaces the latter. 2 : α Marc De Graef Michael I. Ivanov University of California-Davis, Dept. of Chem. Eng. and Matls. of Chem. Eng. and California-Davis, Dept. University of 3 ; : 1 BOC Coating Technology, Fairfield, CA 94533 USA; Fairfield, Technology, BOC Coating Gres Treatment & Minimization Committee Program Organizers: of Mines, Kroll Institute for Extractive Metals, Golden, CO University of Idaho, 80401-1887 USA; Patrick R. Taylor, ID Department of Metals & Mining Engineering, Moscow, 83843-3024 USA PM Wednesday March 15, 2000 Session Chairs: Mines, Metallu. & Matls. Eng., Golden, CO 80401 USA; University of Idaho, Metallu. & Min., Patrick R. Taylor, ID 83843 USA Moscow, 2:00 PM Nitrogen Oxides of Formation during the Combustion of the Blast Furnace and Coke Gases and Their Mixtures Academy of Ukraine, Therm. Eng. Dept., 4 Gagarin Prosp, Dniepropetrovsk 320635UA Ukraine in combination with electron and neutron diffraction to determine the in combination with electron and neutron diffraction be considered to be the metal atom positions. The Cmm2 hydride can from each other in end member of a series of hydrides which differ of three will also report on the analysis terms of defect densities. We different planar defects in the related tetragonal for Waste Processes High Temperature I & Minimization: Treatment by: Sponsored This work was supported in part by the MSU CFMR, and by the US NSF and by the CFMR, by the MSU in part was supported This work and 98-09688. 94-00417 DMR grants MRSEC under PM 4:10 Nano-crys- Grain Growth in Studies of Abnormal In-Situ TEM talline Ag 1 CA Berkeley, Berkeley Lab., Lawrence Microscopy, ter for Electron USA; CA USA Sci., Davis, were DC sputter deposited onto back-etched 80 nm thick Ag films a membranes. Specimens were annealed in amorphous silicon nitride TEM for various temperatures and hold heating stage in an in-situ of the as-deposited films is bi-modal, times. The grain size distribution a with 100 nm diameters, embedded in with large abnormal grains at of 15 nm diameters. Coarsening begins matrix of smaller grains 100 temperatures of approximately only after sufficient temperature increases, The growth process restarts the temperature. Using a variation of and plateaus at each succeeding for the abnormal activation energy the law, Neumann Mullins-Von 0.23 eV consistent with surface diffusion. Grain growth is found to be above temperatures of 350 growth appears to stop formation at 350 ing to triple junction pore film from the substrate at 600 4:30 PM Alumi- in Titanium Phase Transformations Hydrogen-Induced nides Sci. and Eng., Roberts Eng. Hall 130, 5000 Forbes Ave., Matls. sity, 15213-3890 USA PA Pittsburgh, report on the structure determination by means of high resolu- We neutron diffraction of a tion transmission electron microscopy and hydrogen duplex alloy, new ternary hydride in a cast Ti-48Al-2Cr-2Nb charged at 800 The hydride grows to the Cmm2 space group and is pseudo-tetragonal. from the ; ; 1 1 sub- 3 ; Wil- 2 Harriet O 2 : : Hong Geng ; Martin A. Crimp 2 ; Reza Loloee 1 ; Jack Bass 2 Hong Geng Michigan State University, Dept. of Michigan State University, : 1 ; 1 ; William P. Pratt P. ; William 1 Michigan State University, Dept. of Phys. and Astro., Michigan State University, 2 ; Martin A. Crimp 2 Los Alamos National Laboratory, Matls. Sci. and Tech. Div., Tech. Matls. Sci. and National Laboratory, Los Alamos 1 Michigan State University, Dept. of Phys. and Astro., 2B Phys- Michigan State University, 2 ; 1 Michigan State University, Matls. Sci. and Mech., East Lansing, MI Michigan State University, strates, where Py=permalloy (NiFe). Cross-section conventional and high-resolution transmission electron microscopy (CTEM and HRTEM) studies have been performed to investigate microstructural features of interfacial structure, layer the multilayers, such as degree of epitaxy, layer orientations and defects. Fast Fourier transform (FFT) quality, image analysis has been employed to assist interpretation of the HRTEM images. The results will be compared with those from similar polycrystalline magnetic multilayers and spin valves grown by dc sputtering. Matls. Sci. and Mech., 3536 Eng. Bldg., East Lansing, MI 48824-1226 USA; ics Bldg., East Lansing, MI 48824 USA The study of giant magnetoresistance (GMR) in magnetic multilayers and spin-valves has shown that the electrical transport in these materials is structurally dependent at the micro and atomic level, with film growth direction and interfacial structure playing important roles. In (Cu/Co) magnetic multilayers and (Cu/Py/Cu/Py/FeMn) spin- this study, valves have been epitaxially grown using dc magnetron sputtering on (1-10) Nb buffer layers that were deposited on (11-20) Al liam P. Pratt liam P. 48824 USA; East Lansing, MI 48824 USA in multilayer spin valves The Giant Magnetoresistance (GMR) effect Therefore, it is important (SV) is very sensitive to the film structure. to correlate this to characterize the structure of the SV multilayers GMR SV structures, of with their magnetic properties. In this study, and [Nb//Ag/Py/ the form [Nb//Cu/FeMn/Permalloy(Py)/Cu/Py//Nb] were characterized Ag/Py/FeMn//Nb], grown on Si (001) substrates, electron mi- using conventional and high-resolution transmission revealed that the layers are CTEM croscopies (CTEM and HRTEM). growth through the generally polycrystalline with columnar/epitaxial images revealed that the growth of the Nb contacts layers. HRTEM ({110} for BCC and and SV layers occurred on close-packed planes that non-equilibrium analysis also revealed for FCC). HRTEM {111} the SV layers. Computer structures exist in certain regions of some of non-equilibrium struc- simulations and comparisons of the proposed of the microscope used, tures, within the imaging and resolution limits support these findings. 3:50 PM HRTEM Study of Epitaxial Magnetic Multilayers and Spin- Sputtering by Dc Grown Valves 1 MS G755, Los Alamos, NM 87545 USA MS G755, Los Alamos, have been attracting rapidly increasing Nanocrystalline materials mainly due to the potential gain in a wide interest in the last decade One characteristic feature of nano- range of engineering applications. the high volume fraction of surfaces, grain structured materials is The high surface/interface to volume ratio boundaries and interfaces. physical properties in the areas of cata- has contributed to interesting and structural applications. The structural lysts, magnetics, optics, unusual phases with unique properties. constraint may also stabilize tool in the characterization of nanostructured HREM is an excellent spatial resolution. In this presentation, I will materials due to its superb studies on the characterization of the defect review several HREM structure, unusual phases, and structural sta- structure, grain boundary the Specifically, bility of metallic powders/compacts and multilayers. properties of nanostruc- role of defects in affecting the mechanical tured materials will be discussed. 3:00 PM Break 3:30 PM Multilayers Analysis of GMR Spin Valve HRTEM structure (possibly spinodal) with sinusoidal variations of the Mo/Re of the variations with sinusoidal spinodal) (possibly structure by been studied have These phenomena substrate. to the ratio normal EDS and microscopy electron high resolution diffraction, electron of ac- difficulty to the are tied strongly phenomena The techniques. leading to a structural Si vacancies, the high density of commodating structures. “frustrated” series of metastable 2:30 PM Materials by HREM of Nanostructured Characterization Kung Heckman John W.

WEDNESDAY PM 163 Lead andzincpartitioning tothedustproductwas greaterthan99%. product wasdetermined tobenonhazardous,based ontheEPA TCLP. irons wasproduced,atnearly80% ironrecoverytothemetal.Theslag pile. Acastironproductofcomparable qualitytoconventionalcast products, exhibitingthepotential forcompleterecycleofthewaste conducted thusfarweresuccessful atproducingthedesiredfurnace holds potentialasfuelgasforcogeneration. Thedirectsmeltingtests aggregate orconstructionfill.Offgas fromthesmeltingfurnacealso a clean(nonhazardous)slagproductsuitableforrecycleasconcrete baghouse dustcontainingvirtuallyallofthezincfromresidues,and ucts includecastironresultingfromthereductionofoxides, the productionofseveralvalue-addedfurnaceproducts.Theseprod- carbon. Thissolidoxidantadditionisadvantageousbecauseitresults in dant additions(inthiscaseironore)ratherthanairtooxidize the 100% ofthewasteswithoutpriorbeneficiation,andutilizessolidoxi- (i.e., fluidizedbedcombustion),directsmeltingintheEAFcanprocess to otherthermaltreatmenttechnologiesconsideredforthesewastes tests conductedinabench-scaleelectricarcfurnace(EAF).Incontrast This evaluationincludedacharacterizationstudyanddirectsmelting Energy (DOE) AlbanyResearchCenter(ARC),inAlbany, Oregon. in Spelter, West Virginia wasconductedattheU.S.Departmentof Anevaluationofthezincsmelterwastesfromaformersite OR 97321USA Research Center, Off. ofFossilEne.,1450QueenAve. S.W., Albany, Furnace Direct SmeltingofZincSmelterWastes intheElectricArc 3:00 PM cesses. havior oftitaniumthatallowsitsuseintheseverydemandingpro- nium inwastetreatmentsystems,aswelltheuniquecorrosionbe- paper willreviewthecurrentandpossiblefutureapplicationsfortita- producing simplenon-toxicchemicalssuchaswaterandCO ing therigorsofthisprocess,designedtotreattoxicorganicchemicals nium hasbeenidentifiedasoneofthefewmaterialscapablesurviv- tion processesknownassupercriticalwasteoxidation(SCWO).Tita- corrosion behaviorhasmorerecentlybeenutilizedinthenewgenera- environments oftenseeninwasteprocessingsystems.Thisexcellent its alloysareuniquelysuitedtowithstandmanyoftheaggressive employed (oraretheresult)ofwastestreamprocessing.Titaniumand waste product.Highlyoxidizing,acidicsolutionsmustsometimesbe environments thatcanbeencounteredwhenchemicallytreatinga titanium inthesetypeofsystemshasbeentheunusuallycorrosive rization (FGD)systemsofcoalfiredpowerplants.Thedrivetouse been usedformorethantenyearsasliningmaterialinfluegasdesulfu- oxidation (WAO) wastetreatmentfacilities.Inaddition,titaniumhas Titaniumhasprovidednearlytwentyyearsofserviceinwetair Lab., P.O. Box2128,Henderson,NV89009USA cesses Titanium BehaviorandApplicationsinWaste Treatment Pro- 2:30 PM nitrogen oxides. formed whichcanmakeasubstantialcontributiontothe“thermal” of theblastfurnaceandcokegasesortheirmixture-”fuel”NOxare coke gascondensatewerealsoselected.Thus,duringthecombustion the studies,samplesofwaterfromcokequenchingtowerand nitrogen oxidesmyreach10-68%.Inordertocomparetheresultsof sate isfullytransformedintoNOx,thentheportionof“fuel” furnace gasinformofgaseouscompoundsanddissolvedtheconden- have shownthatifallthecombinednitrogenpresentinmeblast of thenitrogen-containingblastfurnacegascomponents.Calculations the off-gasesofblastfurnacestoves,aswelltypeandconcentration carried outtodeterminetheconcentrationsofdeleteriousemissionsin and veryoftentheavailabledataarecontradictory. Studieshavebeen furnace gasandcoketheirmixtures,islackofsuchdata natural gas.Butasfarmetallurgicalfuelsareconcerned,suchblast when heatgeneratingfuelsareburned,suchasfueloil,powderedcoal, formation ofnitrogenandcarbonoxidestheirconcentration, The availableliteraturecontainsadequatedataonthemechanismsof rious emissions(NOx,SOx,CO,andC ous typesoffuelsarecombustedcomprisethemainsourcesdelete- Industrialheatgeneratingfacilitiesandautomobiles,inwhichvari- : J.S.Grauman : W. K.O’Connor 1 ; Stephen P. Fox 1 ; D.C.Dahlin 1 2 ; 0H 1 1 ; P. C.Turner TIMET, HendersonTech. 12 ) intotheenvironment. 1 ; 1 Albany 2 . This of perovskite(CaO.TiO Kineticsofnon-isothermalprecipitateprocessandcrystalgrowth Dept., Shenyang,Liaoning110006PRC Phase inCaO-TiO Kinetics ofNon-IsothermalPrecipitationProcessPerovskite 4:15 PM potential oftheelectronbeamwastetreatmentwillbediscussed. streams. Fundamentalaspectsandapplicationsincludinganeconomic treatment suchasstabilizationofradioactivesolidandliquidhazardous advanced electronbeamconceptsforsolid,liquid,andgaseouswaste treatment technologyinthenotfarfuture.Thispaperwillconsider to useableenergy)suggeststhatthistechniquewillbeamajorwaste energy (80-90%ofthepowerfromelectriclineisconverted A uniquelyhighpowerefficiencyoftheelectronbeamsources pabilities forthehightemperaturetreatmentofhazardousmaterials. Electronbeamprocessingoffersgreattechnicalandeconomicca- Matls. andAdv. Process.,Moscow, ID83844-3026USA Phase inNon-EquilibriumSystems Kinetics ofCoarseningDiffusion-ControlledPrecipitate 4:45 PM fects onthecrystalgrowthofperovskitephase. The particlecoarseninginnon-isothermalprocesshasimportantef- and theexperientialexpressionofaveragecrystalradiuswasobtained. fraction canbedescribedbytheequationgivenK.Matusitaetal. were studied.Theexperimentalresultsshowthattherelativevolume Jabotinski Electron BeamProcessing forWaste Treatment 3:45 PM 3:30 PMBreak industrial-scale. the bench-scalefurnacewouldtranslateto0.400.50kW×h/lbat feed material.Priorexperiencesuggeststhatthesefiguresmeasuredin would beproduced.Energyconsumptionwasroughly1.10kW×h/lbof feed processed,540lb.ofcastiron,600slag,and150dust The materialbalanceoverthefurnaceindicatesthatforeverytonof by themodelpredictingisagreedwithexperimentalresults. CaF systemwasinvestigated.Itisshownthatthecoarseningprocess The coarseningprocessofCaO-TiO were studied,andthenaphysicalmodelofcoarseningwasproposed. Thecoarseningprocessofprecipitatesinnon-equilibriumsystems P.O. Box119, Wenhua Rd.,Shenyang,Liaoning110006 China Zhitong Sui Lou 1 ; Yuhu Xia 1 ; FrancisH.(Sam)Froes 1 ; 1 Northeastern University, Schl.of Matls.andMetallu., 1 ; ZhitongSui 2 -SiO 2 ) phaseinCaO-TiO 2 -Al 2 O 1 ; 3 -MgO System 1 Northeastern University, Metallu. 1 ; 2 inMgO-TiO 1 University ofIdaho,Instit.for : Taiping Lou 2 -SiO : 2 -Al Yuhai Li 2 -Al 2 O 2 3 O 1 -MgO system : ; Yuhai Li 3 -SiO 1 Vadim J. ; Taiping 2 -CaO- 1 ;

WEDNESDAY PM 164 ; 1 Rajiv : Woo-Jin m (heat 1), : ’ phase. The µ γ ; Michel Nganbe and 1 γ C, the reverse behav- ° ’ particles lie in the range of 0.5 γ Martin C. Heilmaier : IFW Dresden, P.O. Box 270016, Dresden D- IFW Dresden, P.O. 1 ; 2 Plansee GmbH, Siebenbürgerstrasse 23, Lechbruck 2 m in diameter (heat 2) and a hot extruded and fully µ University of Missouri-Rolla, Dept. of Metallu. Eng., 218 University of Missouri-Rolla, Dept. of Metallu. 1 ; 1 Hong-Ik University, Metallu. and Matl. Sci., 72-1 Sangsu-dong Metallu. and Matl. Hong-Ik University, 1 m. The high temperature deformation properties of three differ- µ ; 1 ’ particles of cuboidal shape. Additionally, the production by means ’ particles of cuboidal shape. Additionally, ently processed semifinished products have been investigated using compressive and tensile tests under constant true strain rate: a) an as- hipped fine-grained material with a grain size of about 1 to 1 b) a subsequently annealed variant to produce coarser equiaxed grains of around 15 recrystallized material with coarse elongated grains (heat 3). The latter possesses a grain aspect ratio of roughly 100. Similar to the early Gibeling and Nix [2] on MA 6000, heat 1 exhibits a work by Gregory, potential for superplastic flow at high strain rates accompanied by low sup- grain coarsening is effectively necessary flow stresses. Obviously, pressed by a “duplex grain structure” consisting of larger grains in heat 2 lead to a dramatic increase in creep strength and in stress exponent. While heat 3 shows further superiority in creep resistance to heat 2 at temperatures above 800 will discuss the observed differ- ior is observed below that limit. We ences in the high temperature deformation behavior in terms of actual 01171 Germany; D-86983 Germany [1] the creep properties Since the review of Lin and Sherby in 1980 superalloys produced by novel oxide dispersion strengthened (ODS) regained renewed mechanical alloying (MA) techniques have recently Our study is industry. attention from the scientific community and focused on PM 3030, a nickel-based superalloy recently developed by Plansee GmbH Lechbruck (Germany). Due to its high content of Al, PM 3030 is strengthened by a high volume fraction of coarse ordered γ of mechanical alloying enables the incorporation of low volume fractions of incoherent spherical Yttria dispersoids. While the latter are of the order of 20 nm in diameter, the bution to the deformation mechanism of superplastic flow in this flow of superplastic mechanism to the deformation bution material. Invited 2:40 PM Superplastic Ceramics Behavior of Ductility Tensile Kim 121-791 Korea Mapo-ku, Seoul to increase ceramics is shown elongation of fine-grained The tensile the values flow stress, even though function of decreasing as a strong in tensile remains high. This trend exponent of strain-rate-sensitivity based on a “fracture mechanics model”. The elongation is explained for on grain size was also investigated tensile ductility dependence or either under a constant strain rate many fine-grained ceramics the could be well explained quantitatively by stress conditions, and be- The difference in the tensile ductility fracture mechanics model. to ceramics and metallic alloys can be related havior of superplastic mechanisms. The superplastic ceramics deform their different failure by intergranular cracks growing perpendicular without necking and fail axis. In contrast, superplastic metallic alloys to the applied tensile and trangranular mechanisms with commonly fail by intergranular in the neck regions. associated void formation 3:00 PM Invited Plastic- Scale on High Temperature Effects of Microstructural and Composites ity of Dispersion Strengthened Materials S. Mishra McNutt Hall, Rolla, MO 65401 USA for materials with Three microstructural features are important phase particle size second phase particles: matrix grain size, second features influence the and interparticle spacing. These microstructural of microstructural effects The creep deformation and superplasticity. are discussed scale on various creep and superplasticity mechanisms mechanism maps. with the help of microstructure-based deformation mechanisms with mi- Some possibilities of transition in deformation are particularly crostructural scale are presented. These transitions and composites with important for dispersion strengthened materials ultrafine microstructure. 3:20 PM Break 3:30 PM Invited of the ODS Nickel- On the Creep and Superplastic Behavior Based Superalloy PM 3030 Frank E.H. Müller 3 Cr 28 Al(Ti) Gorge 3 Al 69 : U.S. Army 1 ; 1 Al(Cr) 3 Max-Planck Institut fur 1 was derived. This value is ; 2 -1 Andrew Crowson 0.42 and at strain-rates of the ≤ : m 10 microns. Superplasticity occurred Al the activation energy is higher of ≤ 3 ± at test temperatures between 700 and 10 kJmol -1 ± s Al based intermetallic alloy with 3 at. per- 3 -2 Eric M. Taleff, University of Texas, University Eric M. Taleff, ; J. A. Jimenez 1 Room: Bayou E Convention Center Location: Opryland to 10 . Optical microscopy and TEM studies showed -5 Woo-Jin Kim, Hong-Ik University, Matls. Hong-Ik University, Kim, Woo-Jin -1 Structural Materials Division, Materials Materials Division, Structural . Maximum elongations to failure of 300% and more -1 s ; C. Derder 1 -4 Centro National de Investigaciones Metalurgicas, Madrid, Spain 2 C. The overall composition of the iron aluminide was Fe ° ). The emphasis is on developing new knowledge of the fundamen- ). The emphasis is on developing new knowledge 6 order of 10 alloys. However, in unalloyed Fe 900 at strain-rate exponents of 0.33 comparable with activation energies of superplastic flow in Fe about 240 kJmol subgrain formation. Subgrains of the order of 0,3 to 0,4 microns in size revealed, and grain refinement to about 30 microns occurred. Super- plasticity deformation in this iron aluminide is characterized by viscous dislocation glide, controlled by solute drag, in the ordered B2 lattice. After a certain amount of superplastic deformation the samples showed subgrain formation in the strained gauge sections. From this it is concluded, that dynamic recrystallization has an important contri- with small amounts of titanium and carbon. In the thermomechanically processed condition the material possessed a coarse microstructure with an average grain size of 55 were achieved. From thermal activation analysis of superplastic flow an activation energy of 185 Superplasticity in an Fe Frommeyer Ger- 1, Dusseldorf D-40237 Eisenforschung GmbH, Max-Planck-Str. many; cent chromium in solid solution have been investigated in the strain- rate range from 10 tal deformation processes in materials including load transfer, fatigue, tal deformation processes in materials including and shear localiza- creep, transformation toughening, superplasticity, and/or procedures, inclu- tion. In addition, new processing approaches are also being investi- sive of biomimetics and hierarchical materials, behavior and reliability gated to optimize and improve the mechanical in this area with special of materials. This paper will describe programs by Professor Oleg D. reference to contributions that have been made Sherby under ARO support. 2:20 PM Invited Fe Superplasticity in the Iron Aluminide Research Office, Phys. Sci. Direct., P.O. Box 12211, Research Tri- 12211, Box Sci. Direct., P.O. Phys. Research Office, angle Park, NC 27709 USA that can extend The Army continues to develop new materials of conventional mate- systems capabilities beyond the physical limits (ARO) in achieving rials. A major focus at the Army Research Office relationships such capabilities is on understanding the fundamental mechanical properties as between the structure of materials and their stress state, and influenced by composition, processing, environment, preventing or retarding and toughening mechanisms for plasticity, and high strain rates (to fracture; especially at large strains (to 1000%) 10 2:00 PM Invited Mechanical Behavior of Materials Wednesday PM Wednesday Mechanical Engineering Department, Austin, TX 78712- Mechanical Engineering Lawrence Livermore National Lesuer, 1063 USA; Donald R. CA 94550 USA; Chol K. Syn, Livermore, Laboratory, & Manufacturing National Laboratory, Lawrence Livermore Division, Livermore, CA 94550 USA Materials Engineering March 15, 2000 Session Chair: Korea Sci. and Metallu., Seoul, Processing and Manufacturing Division, Structural Materi- Division, Structural and Manufacturing Processing Committee Shaping and Forming als Committee, Organizers: Program Sponsored by: Sponsored Honorary Symposium for Professor Symposium Honorary A Sherby: Superplasticity Oleg D.

WEDNESDAY PM 165 transition strainrateispredictedtobeabout10 tic tonon-superplasticbehaviorwithtemperature.At1200 model isbasedontheincreaseintransitionstrainratefromsuperplas- at ultrahighstrainratesandelevatedtemperaturesispresented.This Apreliminarymodelfortheoccurrenceofsuperplasticphenomena ometry. ment withapointdefectmodelthat incorporatescationnon-stoichi- at highoxygenpartialpressures.Theseresultsareinexcellentagree- cation vacanciesatlowoxygenpartialpressuresand on thedeformationratesuggestedthatrate-controllingdefect is was accommodatedbylatticediffusion.Theeffectofoxygenactivity creep dataforperovskiteoxidesrevealedthatgrainboundarysliding parison oftheactivationenergyforcreepwithexistingdiffusionand trolled bygrainboundaryslidingaccommodateddiffusion.Acom- lack ofgrainshapechangesuggestedthatthedeformationwascon- nent closetounity, absenceofdeformationinduceddislocations and and Srcontent.Thefinegrainsize,briefcreeptransients,stressexpo- range 1150-1300 tive densitiesbetween85-90%wasinvestigatedoverthetemperature Thedeformationoffine-grained(<10mm)La,Sr)MnO Argonne, IL60439-4838USA 20783-1197 USA; Laboratory, AMSRL-SE-DC,2800PowderMill Rd.,Adelphi,MD Russ Cook Creep of(La,Sr)MnO 4:50 PMInvited Bar areinqualitativeagreementwiththepredictionsofmodel. high carbonsteelminiaturetensilespecimensusingasplitHopkinson tions. ResultsonexperimentsARMCOironandfinegrainedultra- temperature rapidly, ascanhappenunderexplosiveloadingcondi- rate forsignificantgraingrowthtooccur,assumingthematerialreaches a grainsizeof1mm.Thereshouldbeinsufficienttimeatthisstrain USA; ates, P.O. Box3015,149CommonwealthDr., MenloPark,CA94025 Eiselstein peratures—Can itOccur? Superplasticity atUltrahighStrainRatesandElevatedTem- 4:30 PMInvited current interestwillbepresented. for usingthesetechniquestoenablethefabricationofcomponents formed. Afterintroducingthefundamentals,examplesandstrategies improved, wrinklingissuppressedandprecise,complexpartscanbe sues inmetalforming.Withhighvelocityforming,formabilityis sive forming,canhavegreatrelevanceintreatingcontemporaryis- show thathighvelocityforming,anextensionof“forgotten”explo- research programinhighvelocitysheetmetalforming.Herewewill learned fromOleg.Theselessonswereputtouseindevelopinga are acoupleofthemostimportantlessonspresentingauthor great respectforsolutionspioneeredinthe“forgottenpast”.These conventional approachestoexistingproblemsorissues,andheshows OlegSherbyhasneverbeenafraidoftakingoriginalevenanti- Matls. Sci.&Eng.,2041CollegeRd.,Columbus,OH43210USA Panshikar Fast Deformation Hyperplasticity: EnablingComplexSheetComponentswith 4:10 PMInvited 2525 PottsdamnerRd.,Tallahasse, FL32310USA Materials Micromechanics-Based ConstitutiveRelationsofSuperplastic 3:50 PMInvited Trans. 16A(1985),777. Mech. 2(1980),251.[2]J.K.Gregory, J.C.Gibeling,W.D. Nix,Metall. microstructurally basedcreepconcepts.[1]J.Lin,O.D.Sherby, Res Abstract textnotavailable 2 Hewlett PackardCorporation 1 1 : ; CharlesG.Schmidt ; SubrangshuDatta 2 ; KenGoretta Namas Chandra ° C asafunctionofappliedstress,oxygenactivity : 2 Argonne NationalLaboratory, Matls.Sci.Div., Glenn S.Daehn 3 ; AFuelCellCathode 2 ; JulesRoutbort 1 ; 1 : ; KeithCrane 2 1 ; Robert D.Caligiuri Florida StateUniversity, Mech.Eng., 1 Exponent FailureAnalysisAssoci- 1 ; Vincent J.Vohnout 2 1 ; ; 1 2 1 s : U. S.ArmyResearch Ohio StateUniversity, -1 Jeff B.Wolfenstine foramaterialwith 1 ; LawrenceE. 3 withrela- 1 ; Hemant ° C, the 1 ; to bearound20005000watts/Km high magnitudeoftheheattransfercoefficientwhichwasdetermined zation, thedropletsizeisanimportantvariablecontributingto dated usingthisatomizationtechnique.Itwillbeshownthatinatomi- a movingmoltendroplethasbeenmodeledandexperimentallyvali- primary atomizationofthestreamisineffect.Theratecooling shown thatatomizationoccursbyRayleighinstabilityandonly analysis willbediscussedasafunctionofprocesscharacteristics.Itis mined fromloadcellmeasurements,videoimagingandparticlesize low carbonsteelandtoolsteel.Atomizationcharacteristicsdeter- metal dropletsincludingPb-Snalloys,aluminumcopper process hasbeensuccessfullyemployedtoproduceawiderangeof and anarrowsizedistributionwithpredictablecoolingrate.The tion techniquethatiscapableofproducingdropletsadesiredsize TheImpulseAtomizationProcess(IAP)isasinglefluidatomiza- Bldg., Edmonton,ABT6G2G6Canada Matls. Eng.,Adv. Matls.andProcess.Lab.,536 Chem.-Matls.Eng. nique Atomization ofMeltsUsingtheImpulseTech- 2:00 PMInvited 3020 USA USA; JamesC.Foley, AmesLaboratory, Ames,IA50011- Standards &Technology, Gaithersburg, MD20899-8556 Session Chairs: March 15,2000 Wednesday PM NIST, Gaithersburg, MD20899-8556USA Gaithersburg, MD20899-8556 USA;StephenD.Ridder, Washington, DC20375-5343USA;FrankBiancaniello,NIST, Laboratory, MaterialsScienceandTechnology Division, Program Organizers: Division, PowderMetallurgyCommittee Sponsored by: tals andPractice:OtherMethods Liquid MetalAtomization:Fundamen- recently developed modelwhichstudiestheformation ofathinfilm and non-ferrousalloyswillbecompared withthepredictionsofa melt attheedgeofrotatingdisk. Experimentalresultsforferrous of themeltwithrotatingdisk andthebreakup/atomisationof possible. Thepaperwilldescribe thebasicphenomenaofinteraction net shapeprocessingviaspraycasting onacylindricalsubstrateisalso reactive andrefractorymetalalloys, anddevelopmentalalloys.Near production ofpowdersferrousandnon-ferrousalloysincluding variant, whichisbasedontherotatingdiskprinciple,suitablefor the developmental alloys,whicharenotavailableinbarform.TheCA means thatREPisoftennotsuitablefortheproductionofpowders of the alloytobeatomisedisavailableinbarform.Thisrestriction rotating electrodeprocess(REP).AbasicrequirementofREPisthat superalloys andsteels.ThemostwidelyusedvariantofCAis the of powdersavarietyalloys,whichincludeAlandTibased Thecentrifugalatomisation(CA)processisusedfortheproduction Guildford, SurreyGU25XHEngland Huiping Li Centrifugal AtomisationofAlloys 2:30 PMInvited production andresearch. as wellitsflexibilitytomeetdifferentprocessingrequirementsfor tics clearlydemonstrateanumberofuniquefeaturesthistechnique the dropletloosesheat.Theseatomizationandheatflowcharacteris- heat fromthedroplettogasisanimportantmechanismbywhich number rangedfromonlyalmost2to10indicatingthatconductionof : Hani Henein 1 ; 1 University ofSurrey, Schl.ofMech.andMatls.Eng., Materials ProcessingandManufacturing Frank Biancaniello,NationalInstituteof 1 ; Location: OprylandConventionCenter Room: BayouB 1 University ofAlberta,Dept.Chem.and Khershed P. Cooper, NavalResearch 2 . Bycontrast,thedropletNusselt : Panayiotis Tsakiropoulos 1 ;

WEDNESDAY PM 166 ; 1 Charles I. : ; Cynthia M. 1 Naval Research Labora- F. Douglas Witherspoon F. 2 : National Materials Advisory 2 Industrial Problem Solving, 910 1 Khershed P. Cooper Khershed P. UTRON Inc., 8506 Wellington Rd., UTRON Inc., 8506 Wellington 1 ; : 2 ; 2 ; Arul Mozhi 1 Naval Research Laboratory, Code 6324, 4555 Overlook Code Naval Research Laboratory, 1 ; ; Khershed P. Cooper ; Khershed P. 1 1 m. This technique replaces the gas stream used in conventional at- Flintlock Rd., Southport, CT 06490 USA; Russell Kincaid 20109 USA; Ste. 200, Manassas, VA Washington, N.W., Ave. Board, Nat. Acad. of Sci., 2001 Wisconsin DC 20007 USA This paper presents results of an ongoing Small Business Innova- tion Research project. This project is developing a new approach to of nm to 20 producing inert gas atomized metal powders of size 10’s µ omization with a pulsed plasma jet to generate a much higher (three orders of magnitude) momentum flux atomizing medium. This new technique has the potential to decrease the cost of production. In The rapidly spinning cup (RSC) atomization process has shown process has (RSC) atomization cup rapidly spinning The Unfortu- powders. metal of fine spherical for the production promise spheres typically fine which promote conditions atomization nately, study A recent morphologies. particle less desirable other, also produce atomization to identify RSC high speed photography has employed examina- This photographic over a range of conditions. mechanisms the melt of the collision between that the character tion demonstrated in both significantly with changes quench liquid could vary jet and the gathered information In this study, liquid velocity. melt and quench of particle combined with a review speed photography is using high size distribution of the resultant powders. morphology and particle are compared to the nature of the melt/quench Particle characteristics evolution of various particle shapes is dis- collision and the probable cussed. 4:25 PM Invited on of Liquid Metal Atomization Media A Study of the Effect Particle Size and Morphology Chambers USA DC 20375-5343 Washington, S.W., Ave. the cup is a convenient tool to investigate The rapidly spinning on the characteristics of atomized metal effect of atomizing liquids cup apparatus is such that the The nature of the spinning powder. Oils and other hydrocar- atomizing liquid media can be easily changed. as atomizing fluids. bons of varying physical properties were selected similar for these liquids, While densities and most other properties are plays a Viscosity viscosities vary by a couple of orders of magnitude. are responsible for melt major role in fostering shear forces which demonstrated a sig- break-up. Experiments with Al-Cu eutectic alloy particle size and particle nificant effect of atomizing media on mean There was no correlation between mean size and viscos- morphology. heat capacity may be ity suggesting that other properties such as with Bi-Mn eutec- playing a role. Similar experiments were performed Bi-Mn is denser than Al-Cu and expands upon solidification. tic alloy. in terms of liquid metal The results of these studies will be discussed break-up mechanisms and solidification behavior. 4:50 PM Invited Gain Insight into the Using Multiple Regression Analysis to Physical Mechanisms in Spinning Cup Atomization Whitman DC 20375- Washington, S.W., Code 6324, 4555 Overlook Ave. tory, 5343 USA gain insight into the By using Statistical Modeling one can often a process, and suggest fundamental physical processes going on in with molten tin process improvements. Here, some 54 experiments were analyzed by Mul- performed at the Naval Research Laboratory model containing some tiple Regression to develop a mathematical nine terms. The model, which contained an unusual three factor interaction, was used to explain this interaction as an effect resulting from the use of a smaller orifice in some of the experiments. This model also explained the presence of small amounts of “encapsulated” particles in the powder, and led to a design change in a larger atomizer to control such particles. Further, also explained was the role of turbulence in coarsening the average particle size of powder produced in the process. The effect of changing the melt to eutectic Al-Cu was also explored. 5:15 PM Invited Modeling and Experiments on Using a New Pulsed Power Tech- Fine Metallic Powders nique to Produce ; ; 2 1 m µ Stephen : Jung-Hoon Chun Melissa E. Orme Melissa E. ; 1 : Naval Research Laboratory, 2 Samsung Information Systems 1 ; 3 Pyongwon Yim Bodycote IMT Inc., Rsch. and Dev., 1 : ; 2 ; Juan Carlos Rocha 2 ; Khershed P. Cooper ; Khershed P. 1 Massachusetts Institute of Technology, Lab. for Manu. and Lab. for Manu. Massachusetts Institute of Technology, Applied Materials, Santa Clara, CA USA 2 3 University of California, Mech. and Aero. Eng., Irvine, CA 92697- Aero. Eng., Irvine, of California, Mech. and University Matls. Sci. and Tech., 4555 Overlook Ave. S.W., Code 6324, Washing- S.W., 4555 Overlook Ave. Matls. Sci. and Tech., ton, DC 20375 USA J. Mashl MA 01810 USA; 155 River St., Andover, diameter tin jet does not break into droplets when the oxygen concentration levels are above 1600-1800 ppm. 3:45 PM Break 4:00 PM Invited Rapidly Spinning Cup Atomization: Correlation of Particle Characteristics with the Melt/Quench Liquid Impact It is well known that as a laminar, liquid jet issues from a small It is well known that as a laminar, liquid mediates the cylindrical orifice, the surface tension force of the liquid In 1878 Lord Rayleigh jet to break up into a train of spherical droplets. of free lami- advanced a linear analysis of the break-up phenomenon droplets can be pro- nar jets. He further demonstrated that uniform oscillation of wavelength duced when the jet is subjected to a periodic recent decades, wave- greater than the circumference of the jet. In jet diameter have been lengths of three-and-a-half to seven times the liquids such as water and used to produce uniform droplets of various on the jet diameter, the ink. The break-up length of a liquid jet depends and frequency of physical properties of the liquid, and the amplitude the break-up length of a oscillation applied to the jet. Prediction of reactive molten metal jet, however, is more difficult when it is sprayed into an oxygen-laden atmosphere. Metal-oxygen gases may form oxides or other tenacious films on the jet surface. In some cases such surface films stabilize the jet, which results in the production of fibers instead of droplets. Thus, determination of the critical concentration of oxygen below which the molten metal jet can be broken into a train of uniform droplets is of paramount importance to the successful applications of the break-up phenomenon of molten metal jets. This paper reviews the break-up behavior of laminar, liquid jets and investigates the role of oxidation in the break-up behavior of liquid tin jets to establish the maximum concentration of oxygen below which jet instability can be promoted by experimentally varying the oxygen concentration from 5 to 200,000 ppm. It was observed that a 100 Nannaji Saka San Jose, CA 95134 Plumeria Dr., 75 W. America, Hdd R&D Ctr., USA; Room 35-233, Cambridge, MA 02139 Product., 77 Massachusetts Ave., USA; 3975 USA has recently break-up into droplets of capillary stream The science applications academic interest for industrial and attracted significant particle production. Exploitation of the high requiring uniform metal intrinsic to the process and the unparalleled droplet production rates sizes and speeds attained with proper applied uniformity of droplet to stream make many new applications related forcing to the capillary of structural components and electronic the net-form manufacture research results on the uniform production packages feasible. Recent alloy droplet streams for the application of aluminum and aluminum will be presented. Issues affecting the drop- of net-form manufacturing as oxidation, corrosion by molten aluminum let stream stability such at elevated temperatures are presented. and other chemical reactions production of solder drop- new research on the uniform Additionally, to electronic package manufacturing is also lets for the application to all molten metals such as the basic phe- presented. Issues common break-up into droplets, nomenon of capillary stream formation and design, electrostatic acoustic excitation issues relevant to apparatus or particle “sorting” charging and deflection for high speed “printing” for more flexible droplet applications, and novel forcing disturbances production are discussed. 3:20 PM Invited the Break-Up Behavior The Effect of Oxygen Concentration on Liquid Metal Jets of Laminar, 1 melt on the rotating disk and the break up of the melt at the edge of melt at the up of the the break disk and the rotating melt on regimes. atomisation for different disk the rotating Invited 2:55 PM Droplet Molten Metal in Highly Controlled Recent Advances Break-up from Capillary Stream Formation

WEDNESDAY PM 167 effect onthefatigue performance.Theresultledto theestablishment differences, the incorporation ofmirrorpolishing hadasignificant properties. Whilevibratorypolishing alsoledtoonlyminorproperty distribution ledtorelativelysmall differencesinthemeasuredfatigue test program.Variations inalloychemistryandtheresultingphase ally, thevariablesofmean stressandfrequencywereincludedinthe and mirrorpolishinginperformance werealsoinvestigated.Addition- most commonconditionforservice, therolesofvibratorypolishing stand theforcesoffatigue.Althoughascastsurfacesrepresent the form thebasisforstructuralcomponentsdesignedtosuccessfullywith- upon theadditionofaluminum,manganeseandzinctobasemetal tions tocomplexengineeringdesignchallenges.Today, alloys based high performance,lowweight,costefficient,andfullyrecyclablesolu- Magnesiumalloydiecastingprovideopportunitiesforachieving 2 K. Nerdahl Alloys Elements oftheFatigueProcessinMagnesiumDieCasting 2:25 PM limit. wear tookplacewhentheappliednormalloadexceededcritical the wear-instage,abrasionwasfoundtobepredominant.Oxidative wear ratewasgreatlyreducedafterthewear-inphenomenon.During posites wasfoundtoincreasewithincreasingslidingdistanceandthe (EDAX). ThewearresistanceperformanceofmagnesiumAZ91com- electron microscopy(SEM)andenergydispersiveX-rayanalysis surfaces ofpinsandtheweardebriswereinvestigatedbyusingscanning counterface consistedofmildsteeldisks.Aftertheweartests,worn The magnesiummatrixcompositeswereusedaspinswhilethe were carriedouttostudythewearperformanceandmechanisms. vol.% SiCwerebeinginvestigated.Pin-on-diskdryslidingweartests powder metallurgytechniqueandreinforcedwith0,5,10,15,20 ThewearresistanceofmagnesiumAZ91compositeproducedby Malasia, FacultyofMech.Eng.,Johor,Skudaim81310Malaysia AZ91 Composite Wear ResistancePropertyandMicrostructure ofMagnesium 2:00 PM ogy Center, PointeClaire(Montreal),Quebec,Canada Session Chair: March 15,2000 Wednesday PM Association, McLean,VA 22101USA 60439-4815 USA;ByronB.Clow, InternationalMagnesium John N.Hryn,Argonne National Laboratory, Argonne, IL Corporation ofAmerica,SaltLakeCity, UT84116 USA; Program Organizers: Committee, InternationalMagnesiumAssociation Sponsored by: and MechanicalProperties Magnesium Technology 2000:Physical fine iron-basedpowdersfromthisongoingprojectwillbepresented. inert atmosphere.Experimentalandmodelingresultsonproductionof geometry nozzleregion.Theatomizedpowdersarecollectedinan to generatethemeltstreamwhichisthenatomizedinaconfined iron-based powdersforcharacterization.Aninductionfurnaceisused prototype todemonstratetheproductionof23kgbatchesfine 3 nm).IntheongoingPhaseII,UTRONisbuildinganengineering II willresultinmetalpowdersthe10’s ofnm(theoreticallydownto Calculations predictthatexperimentalconditionsachievableinPhase and steelpowdersofsize0.5to6.0 Phase I,finesphericalcopperpowdersinthesizerange0.2to8.0 SINTEF : Terje Kr. Aune 2 ; 1 Norsk Hydro,Rsch.Ctr., PorsgrunnN-3901Norway; : Light MetalsDivision,Reactive Mihriban O.Pekguleryuz,NorandaTechnol- Jamaliah Idris 1 ; DarrylL.Albright Location: OprylandConventionCenter Room: BayouC Howard I.Kaplan,Magnesium 1 ; J.C.Tan µ m, weresuccessfullyproduced. 1 ; OddvinOrjasaeter 1 ; 1 Universiti Teknologi 2 ; Odd µ m, tion Tool Deformation-Induced Texture asanAlloy/Process Optimiza- 3:15 PM sults. porosity and/orlaminationwerealsoperformedtodocumentthere- orientations, andmacrographsoffracturesurfacesincludingonewith of fracturesurfaces,Metallographysurfacesparalleltothedifferent the flawscouldhavenegativeeffects.ScanningElectronMicroscopy have influencedthefracturetoughnessinotherorientationswhich tion isnotinfluencedbytheorientationofporosity, butcould toughness valuesmeasuredbecauseofthedirectioncrack-propaga- specimens showedsomeporosity, whichdidnotinfluencethefracture ness testing.Fracturesurfacesonsomeofthetestedcompacttension also confirmedthestabletearingbehaviorobservedinfracturetough- orientation effects.Forcevs.displacementtracesfromCharpytesting also confirmedthatthefracturetoughnessisgenerallyindependentof pact tensionspecimenscouldnotbeprepared.Charpyimpacttesting specimens weretested,aswellinotherorientationswhichcom- prepared inthesametwoorientationsasthosewhichcompact orientation onfracturetoughness.SubsizeCharpyspecimenswere measured. Thesetwoparametersdidnotrevealanyeffectofspecimen gage capacity.Values oftheTearing Modulusanda“KformJQ”were and testingwasdiscontinuedwhencrackextensionexceededtheclip tions andtwotemperatures.Resultsindicatedstabletearingbehavior, the fracturetoughnessbehaviorincludedtestsintwodifferentorienta- using of5-mmthickcompacttensionspecimens.Characterization ThefracturetoughnessofMagnesiumAlloyAM60Bwasmeasured, USA Fracture Toughness ofMagnesiumAlloyAM60B 2:50 PM accumulation. of designcurves,alongwithaproposedmodelforfatiguedamage material process orjoinprocess.Theincreasing demandofcheap production procedure comparedtothealternative extensiveremove superplasticity formingofmetals andtheiralloysisaninexpensive highly terminalmeasurementsof componentsbythemeansof to conventionalconversionprocedures. Especiallytheproductionof complex formedfinishedproducts canbedrasticallyraisedcompared rials theproductivityofprocessing ofsemifinishedproductsto Throughtheuseofsuperplastic behaviourofmagnesiummate- Clausthal D-38678Germany Fertigunsvefahren, Tech. UniversitatClausthal,Agricolastrasse2, C. Kedenburg Superplasticity ofMagnesiumAlloys 3:50 PM 3:40 PMBreak basal plane. lithium promotesdislocationslipontheprismplanesaswell the the ductilityofmagnesiumandtextureanalysishasconfirmedthat tential ofthisapproach.Theadditionlithiumisknowntoenhance ing lithiumhavebeenparticularlypotentfordemonstratingthepo- twinning, etc.).Hexagonalclosepackedsolidsolutionalloyscontain- is largelyduetothelimitednumberofactivedeformationmodes(slip, advantage ofatexture-basedapproachbecausethelimitedformability This factmakesmagnesiumanidealcandidatetodemonstratethe alloys ismoderate,theirlowtemperatureformabilityquitelimited. plasticity. Althoughtheductilityoftraditionalwroughtmagnesium geometry andtheactivedeformationmechanismsthatsustained results fromdeformationisafingerprintoftheimposed sight intotheseissues.Thepreferredorientation(ortexture)which ate polycrystalplasticitysimulationtechniquescanproviderapidin- tion modes.Deformation-inducedtexturedatacoupledwithappropri- strength andductilityarestrongfunctionsoftheoperativedeforma- ticularly fornon-cubicand/ororderedintermetallicalloyswhere necessary componentofhighperformancealloydevelopment,par- Understandingwhichdeformationmechanismsareactiveisoftena TN 37831USA 37831-6083 USA; National Laboratory, Bldg.4508,MS6083,Rm.135,OakRidge,TN R. K.Nanstad : S. R.Agnew 1 ; S.Viswanathan 1 ; 2 Case Western ReserveUniversity, Cleveland,OH 1 Institute furSchwelstechnikundTrennende 1 ; 1 Oak RidgeNationalLaboratory, OakRidge, 1 ; R.L.Swain : U.Draugelates 1 ; J.F.Wallace : S. K.Iskander 1 ; A.Schram 2 ; 1 Oak Ridge 1 1 ; ;

WEDNESDAY PM 168 ; 1 Mark W. Mitsubishi 1 : ; 3 ; Alan Huffman 1 ; Keigo Obata 2 Daiwa Fine Chemicals Company 3 ; Salvatore Bonafede 1 ; Kiyotaka Tsuji Yellapu V. Murty, Carpenter Technol- Carpenter Murty, V. Yellapu 1 Room: Lincoln C Location: Opryland Convention Center MCNC, Elect. Tech. Div., 3021 Cornwallis Rd., Div., MCNC, Elect. Tech. 1 Sung K. Kang, IBM, Yorktown Heights, Sung K. Kang, IBM, Yorktown ; Electronic, Magnetic & Photonic Materials Magnetic & Photonic Electronic, 1 ; Phil A. Deane 1 Ishihara Chemical Company Limited, 5-26, Nishi-Yanagihara, 2 Masayoshi Kohinata : Sundeep Nangalia 2:00 PM Opening Comments 2:05 PM Chip Bump Forma- Low Alpha Solder Electrolyte Used for Flip tion Sanda, Hyogo 669-1339 Materials Corporation, 12-6, Technopark Japan; Hyogo-Ku, Kobe 652-0806 Japan; Kobe 652-0047 Limited, 1-17, 2-Chome Shimosawa-Dori, Hyogo-Ku, Japan for flip chip have developed a low alpha solder electrolyte used We the alpha particle count bump formation. It is generally known that but increase with low, from the deposit immediately after plating are count from the deposit time. Using our electrolyte, the alpha particle of the bump plated for can be very low and stable. The characteristics are given, including the 63% tin and for 5% tin solder electrolytes uniformity of the bump height and the bump compositions over the The starting materials and electrolyte are fully developed, so wafer. also describe an our electrolyte is already in mass production. We evaluation method for the electrolyte that controls parameters influencing bump characteristics. 2:30 PM Low-Alpha Lead for Solder Bumping Production Research Triangle Park, NC 27709 USA Soft-errors caused by lead in solder-bumping have been a concern for many years. The problem is of special concern for high-density interconnection applications requiring solder to be placed directly over In that situation, alpha particles emitted by radioac- active circuitry. For tive lead cause soft-errors with no possibility of shielding circuitry. optimal cost-effectiveness, though, not all solder bumped wafers require low-alpha lead. MCNC has developed a solder bumping facility with both a research branch at MCNC and a full-scale production present results here Unitive Electronics Inc. We facility at its spin-off, of our work in incorporating low-alpha lead as part of our solder describe the amount of cross-contamination bumping process. We measured when alternating plating baths of regular lead and low-alpha Materials Issues in Microelectronics: Issues Materials Low and Thermal: Electrical, Optical, Pb and Applications Alpha by: Sponsored and Interconnection Electronic Packaging Division, Committee Materials Organizers: Program and Development, Reading, PA ogy Corporation, Research Godavarti, Motorola, Austin, TX 19612-4662 USA; Prasad Bell Laboratories, Lucent Technologies, USA; Sung-Ho Jin, USA; Sung Kang, IBM, TJ Watson Murray Hill, NJ 07974 NY 10598 USA; John Heights, Yorktown Research Center, LLC., Newark, DE 19711 Macwilliams, US Competitors, Fujitsu Computer Packing Tech- USA; Mark McCormack, CA 95134 USA; Martin Weiser, nologies, San Jose, Materials, Plated and Discrete AlliedSignal Electronic 99216 USA WA Products, Spokane, PM Wednesday March 15, 2000 Session Chairs: Austin, TX NY 10598 USA; Prasad Godavarti, Motorola, 78721 USA Roberson ; E. S. 1 Indian Institute of ; D. Taplin 2 1 ; W. Zhou ; W. 1 A. Bag : Nanyang Technological University, Schl. of Mech. & University, Nanyang Technological 1 ; 2 Dwarakadasa India Science, Dept. of Metallu., Bangalore 560012 and light weight design Increasing demand for lighter components as possible engineering has led to magnesium alloys being considered fatigue strength has been materials in the last few years. However, low alloys in more an important factor in the limited use of magnesium matrix composites highly stressed designs. In particular magnesium addition of a reinforcing are attracting a lot of attention because the produce a remarkable phase, such as ceramic particles or fibres may with ceramic improvement in the property profile. Reinforcement modulus and Young’s particles can lead to an increase in strength, the coefficient of hardness, particularly at room temperature whereas of SiC particles to thermal expansion is reduced. However, addition resistance. Therefore the AZ91D matrix may result in lower fatigue of AZ91-10%SiC present investigation examines the fatigue properties and compares them composite in different heated treated conditions growth study was con- Fatigue crack with the monolithic AZ91 alloy. with the load ratio of ducted by using half-compact tension specimens by optical and scanning R= 0.1. Crack growth tests supplemented the role of magnesium electron fractography have been used to assess ceramic particle interac- matrix, which has HCP crystal structure and near threshold behaviour tions on the crack initiation, propagation and The magnesium alloy. and finally to compared with the monolithic heat treatment can im- experimental results show that appropriate alloy and its composite. prove the crack growth behaviour of AZ91 Product. Eng., Nanyang Ave. 639798 Singapore; Product. Eng., Nanyang Ave. producable products capable of withstanding high stress and due to the and due high stress of withstanding capable products producable energy material and wanted and the weight products to light restraint the high and astronautics, aeronautics in the fields especially savings but construction, equipment and automobile railway systems, speed the grow- has brought about data processing technology also news and procedure is One reason for this in superplastic forming. ing interest structural highly thin-walled suitability of manufacturing the special emphasizes The presentation for the light weight design. components presentation part of the subjects: In the introductory the following are behavior of magnesium-alloys for the superplastic presuppositions quantify the superplastic behavior and the im- discussed. Methods to derived thereof are explained in the follow- portance of the m-values for superplastic forming is a very fine ing. Since a major precondition possibilities of grain-fining-procedures of mag- grain structure, various with the help of parameter-lists and pic- nesium-alloys are described are the results of the investigations Finally, tures of grain-structures. and an outlook to closer aims of the research graphically displayed program is given. 4:15 PM AZ91D Magnesium Alloy and its Com- Fatigue Behaviour of with SiC posite Reinforced

WEDNESDAY PM 169 we demonstrate a 3-Delectromigrationmodelthat wasdeveloped is muchmorepowerful tosolvethecomplexproblems. Inthispaper, force. Numericalsimulation,especially finiteelementanalysis(FEA), mensional andapplythehydrostatic stressasthechemicaldriving very simplifiedconditions.Inmost cases,thosemodelsareone-di- complex, analyticalsimulationmethods onlygivetheresultsunder ity. Whiletheelectromigrationanditsrelatedphenomena arerather electromigration inaparticularposition tointerconnectionreliabil- the chiparereducedandcurrentdensityincreases.Thisputs AsICdevicesscaledown,thecrosssectionofinterconnectlines on Hall, Rm.356,Ithaca,NY14853USA Che-Yu Li Interconnections 3-D SimulationsofElectromigrationandStressEvolution in 4:00 PM mination ofphaseequilibriaareingoodagreement. sessed inthisstudy. Thecalculatedresultsandtheexperimentaldeter- ent systems,thermodynamicmodelsoftheAg-Sn-Cuhavebeen as- knowledge ofthethermodynamicmodelsitsthreebinaryconstitu- Based ontwoexperimentallydeterminedisothermalsectionsand the at 450 equilibria, ande1phaseisstillinequilibriumwithAg,ze2phases ence ofd-Cu4Snphaseat450 is inequilibriumwithAg,z-Ag4Sn,ande2-Ag3Snphases.Theexist- have beenexperimentallydetermined.At240 alloys areexaminedandtheisothermalsectionsat240 system isthusofimportanceinelectronicindustry. Various Ag-Sn-Cu most popularsubstrate,andthephaseequilibriaofAg-Sn-Cuternary Ag-Snalloysareaprominentgroupoflead-freesolders.Cuisthe Eng., #101Sec.2Kuang-FuhRd.,Hsin-Chu,Taiwan 300 Sinn-wen Chen Phase EquilibriaofAg-Sn-CuTernary System 3:35 PM 3:20 PMBreak of thematerial. alpha emissionrateandtogaininsightintothedecaycharacteristics processing alphaemissionfluxtestingisperformedtodeterminethe extremely lowconcentrationleveloftheisotope210Pb.Postpowder this reliabilityconcern,itwasnecessarytoobtainaleadsupplywithan isotope impuritiesfoundinleadcontainingsolders.Inordertoaddress phenomena ofradioactivedecayinducedsofterrorsgeneratedbytrace solder bumpinterconnects.Industryconcernshavegrownoverthe chip featuresizehasledtoacloserproximityoflogicelementsandthe ful monitoringtoinsurelotconsistency. Thereductioninon- consequently theamountofsurfaceoxideincreasesandrequirescare- duced toenhanceprintdefinition,thesurfaceareaofpowderand bution andoxidecontent.Furthermore,aspowderparticlesizeisre- that influenceparticleshape,surfacemorphology, particlesizedistri- were conductedtoidentifythecriticalprocessvariablesandconditions produced withreasonablefinalyields.Various designedexperiments type 6powderasspecifiedbyIPCinstandardJ-STD-006couldbe cess optimizationrevealedthatbyinstitutingadditionalcontrols,a necessary tooptimizeboththepowderprocessandfluxsystem.Pro- the higherprintresolutionsdemandedbyflipchipprocess,itwas solder pasteandprocessusedforflipchipbumping.Inordertoachieve dimensions, higherandfirstpassyieldswillberequiredofthe numbering inthethousandsofbumps/printateverdecreasingpitch being oneofthosecriticalmaterials.Withtheadventbumparrays straints onpackagingmaterialsandtheirrelatedprocesses;solderpaste corresponding decreasesindevicegeometryhasplacedtightercon- materials. Furtherincreasesindevicespeedandfunctionalitywith present newchallengestothesuppliersofsemiconductorpackaging Therapidgrowthinchiplevelinterconnectiondensitycontinuesto CA 92131USA 1 Chip Bumping A LowAlphaEutecticType 6SolderPasteforUltraFinePitch 2:55 PM measured withalphadetectioncounters. lead. We alsopresentgeometriccorrectionfactorsforsolderbumps Johnson MattheyElectronics,10080WillowCreekRd.,SanDiego, ° C, whichindicatesthatthee1phaseisaverystablephase. 1 ; 1 Cornell University, Dept.of Matls.Sci.andEng.,Bard 1 ; : : 1 Mike Grosse National Tsing-Hua University, Dept.ofChem. Zhineng Fan ° C doesnotchangemuchofitsphase 1 ; JimGrundy 1 ; SvenRzepka ° C, thee1-Cu3Snphase 1 ; Tom Herrington 1 ; MattKorhonen : Yee-wen Yen ° C and450 ° C 1 1 1 ; ; ; Rsch. Ctr., P.O. Box218,Yorktown Heights,NY10598USA; trically ConductingAdhesiveMaterials Characterization ofElectroplatedBismuth-TinAlloysforElec- 4:25 PM sion. driving forcewilloverestimatethebackflowofstress-drivendiffu- paper. Itisshownthatbyusinghydrostaticstressasthechemical and hydrostaticstressonthegrainboundaryarepresentedinthis sides wassurveyed.Theevolutionoftheatomicflow, normalstress polycrystalline sectionwithbamboostructureconnectedtoitatboth the chemicaldrivingforce.Theinterconnectsegmentconsistinga Coble creepandNabarro-Herringbyapplyingnormalstressas based onacommercialFEAcode.Themodeliscapabletoinclude erty measurementsonactualsolderjoints. sults indicatethereasonablepossibilityofmakingvalidtensileprop- terms ofrelevantalloycharacteristicsandmicrostructures.The re- ders. Detailsofthedatacomparisonswillbepresentedanddiscussed in solder bumpsagreedwellwiththosefromthetensilespecimenshoul- long x0.8mmwide0.30-0.50thick.ABItestresultsfrom the the samealloy. Thesolderbumpshadnominaldimensionsof2.5mm boards wereobtainedthatcontainedarraysofsolderbumpsmadewith ing ratecomparedtothetensiletestdata.Subsequently, small FR4test lower yieldstrengthandslightlyhigherflowstressesworkharden- ment ofthedatasetswasgood,withABIindicatingaslightly on theshoulderregionsoftensilespecimens.Theoverallagree- alloy andtestingthematroomtemperature.ABItestswerethendone preparing 1.5-mm-thicktensilespecimensofbulkaSn-3.5Agwt% interest fortestingsolderjoints.Thetechniquewasevaluatedbyfirst sure mechanicalpropertiesinsmallvolumesofmaterialmakesit developed foralloysotherthansteels,butitsapparentabilitytomea- Theautomatedballindentation(ABI)testingtechniqueisnotwell Gaithersburg, MD20899USA tional InstituteofStandardsandTechnology, Rm.223-B164, 3135, SRL,P.O. Box2053, Dearborn,MI48121-2053USA; USA; Met. &Cer. Div., 1BethelValley Rd.,OakRidge,TN37831-6096 Tsung-Yu Pan L. Buchwalter the Tensile Properties ofSolderAlloys An EvaluationofAutomatedBallIndentationforMeasuring 4:50 PM ing mechanismofthenewly-developedPb-freeconductiveadhesive. experimental resultshaveprovidedabetterunderstandingofthejoin- structure, electricalproperties,oxidationbehaviorandothers.The electroplated BiSnalloysonaCusubstrateisreportedfortheirmicro- ticles aswelltothesubstrate.Inthispaper,characterizationof melting pointlayerservesasajoiningmaterialamongthefillerpar- with alowmeltingpointmetaloralloy, suchasSnorBiSn.Thelow conducting adhesivecontainsaconducingcopperfillerpowdercoated for lowtemperatureapplicationshasbeenpreviouslyreported.This them, anewhighconductivityPb-freeconductingadhesivedeveloped tions, severalnewformulationshavebeendevelopedrecently. Among the requirementsofsolderjointsyet.To overcometheselimita- common silver-filledepoxymaterialshavevariouslimitationstomeet (Pb)-containing soldersinmicroelectronicapplications.However,most Electricallyconductingadhesivesarepromisingalternativesforlead Matls. Sci.&Eng.,Cambridge,MA02139USA 2 Ford MotorCompany, FordRsch.Lab.,20000RotundaDr., MD 1 2 ; CorneliaK.Tsang ; FrankW. Gayle 3 ; 2 ; 1 Oak RidgeNationalLaboratory, 1 IBM, Rsch.Dept.,T.J. Watson : : Sung K.Kang Michael L.Santella 1 ; Stephen 2 MIT, 3 Na- 1 ;

WEDNESDAY PM 170 Laboratoire de Science 1 ; 1 University of Alberta, Adv. University of Alberta, 1 ; 1 James A. Hall, Oremet-Wah Chang, James A. Hall, Oremet-Wah Room: Knoxville B Location: Opryland Convention Center Hani Henein A. Jardy D. Ablitzer : : Kuang Oscar Yu, RMI Corporation, R & D, Kuang Oscar Yu, Materials Processing and Manufacturing 2:00 PM Re- Arc to Optimize Vacuum Solar: A Numerical Software melting Operations et Genie des Materiaux Metalliques, Ecole des Mines, Parc de Saurupt, Cedex F-54042 France Nancy, Process Synthesis and Modeling for the Process Synthesis and Modeling of Titanium & Production & Processing Its Alloys: Session IV Sponsored by: Matls. and Process. Lab., 536 Chem.-Matls. Eng. Bldg., Edmonton, Matls. and Process. Lab., Alberta T6G2G6 Canada and power of the PC as well as the education The easy accessibility in the use of these tools, are compelling of our engineering students computer aided instructional (CAI) tools. There reasons for developing in the engineering curriculum where students is a wide range of areas the application of judgment for prob- must learn concepts involving the instructor of a throughout North America, lem solving. Typically, guidelines to students on how to apply course will provide theoretical the All too often, these points are lost on the required judgment. too too complicated and too abstract. It is often student as it is deemed students to the point where they can practice time consuming to get packages have therefore this judgment. A number of computer aided the materials science and been developed for use in several courses in calculational and instruc- engineering curriculum that encompass both of some of these tional capabilities. This talk will present an overview the instruction of packages on the solution of a non-linear equation, crystallography and an binary diffusion couples, an introduction of in which these CAI Tutori- The context introduction to heat transfer. discussed. The use of the als were developed and are being used will be expectations from an tutorials has important implications on the student. engineering education of both instructor and 3:00 PM Break 3:10 PM Open Discussion and Software Demonstration Materials Processing in The Role of Computer Based Training 3:50 PM Closing Remarks Division, Structural Materials Division, Titanium Committee, Shaping and Forming Committee Organizers: Program H. (Sam) Froes, University of OR 97321 USA; F. Albany, ID 83844-3026 Idaho, IMAP-Mines Bldg. #321, Moscow, USA; Kuang Oscar Johnson Matthey, USA; Isaac Weiss, RMI Corporation, R&D, Niles, OH 44446-0269 USA Yu, PM Wednesday March 15, 2000 Session Chairs: Chang, Niles, OH 44446-0269 USA; James Hall, Oremet-Wah OR 97321 USA Albany, (e.g., programming)—to be fully effective individual educators and educators individual fully effective be programming)—to (e.g., others to rely on tools and not of the to take control need researchers setting educational in an to recognize, (2) the need them, and do it for impor- web page is of a infrastructure although the that in particular, is supported hard content. The work component is the tant the critical Services, & Distributed Computing from Academic by a TEL grant NSF under Grant NSF/EEC-9711743. Minnesota and by the University of 2:40 PM and Engi- in Materials Science Aided Instruction Computer neering Education Vaughan : University of Alabama, Metallu. & 1 ; 1 Vaughan Voller, University of Voller, Vaughan Room: Lincoln A Convention Center Location: Opryland Brian G. Thomas, University of Illinois, Brian G. Thomas, University Extraction & Processing Division, Materials & Processing Division, Extraction Garry W. Warren University of Minnesota, Saint Anthony Falls Lab., Missis- 1 : ; 1 sippi River at 3rd Ave. S.E., Minneapolis, MN 55414 USA sippi River at 3rd Ave. Wide Among the recent innovations of the computer age the World has and will continue to have a significant impact in teaching, Web education and research dissemination. This paper explores some ex- and associated resources for teaching and amples of use of the Web research in the materials processing field. Specific examples will include: An outline of authoring tools for preparing engineering learning of simple Quizzes Preparation modules. HTML for interactive Web programs in scripting lan- GIF animations. Running Interactive Web For the most part the examples will be guages (e.g., JAVA-Script). The central pur- taken directly from the experiences of the author. pose will be to show the accessibility and ease of use of available tools and demonstrate how a small amount of effort can lead to a significant value added to education and research endeavors. The key messages are (1)—taking note of other computer innovations of the last 50 years R. Voller 2:00 PM 8th Grade Science-A Introducing Materials to 6th, 7th and First Step Matls. Eng., P.O. Box 870202, Tuscaloosa, AL 35487 USA Box 870202, Tuscaloosa, Matls. Eng., P.O. with a materials com- Computer Aided Instructional (CAI) software science classes. The ponent have been developed for 6th to 8th grades activities of the NSF software is a result of the educational outreach Center for Materi- sponsored MRSEC at the University of Alabama’s A primary emphasis of the MRSEC’s als for Information Technology. with a very in- educational outreach activities involves collaboration (IS) curriculum based in novative 6th to 8th grade Integrated Science at the Technology the Center for Communication and Educational are teachers in this University of Alabama. Three of the authors packages dealing program and participated in producing three software and (3) The Table with (1) Simple Machines (levers), (2) The Periodic packages probably Scientific Method. In many cases these software topics, therefore a pri- represent the students first exposure to these to present the informa- mary objective behind their development was convey important tion in a fashion that would retain student interest, and reinforce other and above all complement information accurately, on making the software classroom activities. Emphasis was placed by answering truly interactive, requiring the student to participate moving objects, sounds questions, selecting options and by incorporating and rewards for correct answers. Wherever possible interesting materials and applications thereof are incorporated. The financial support of gratefully ac- program is the NSF Research Experiences for Teachers knowledged. 2:20 PM and Research in Materials Teaching Use of the Web Wednesday PM Wednesday Minnesota, Saint Anthony Falls Laboratory, Minneapolis, Falls Laboratory, Minnesota, Saint Anthony Hani Henein, University of Alberta, MN 55414-2196 USA; 2G6 Canada; Sulekh Jain, Ge Aircraft Edmonton, AB T6G Cincinatti, OH 45215 USA Engineering, MId M-89, March 15, 2000 Session Chairs: Warren, IL 61801 USA; Garry W. Mech. Eng. Dept., Urbana, Metallu. & Matls. Eng., Tuscaloosa, University of Alabama, AL 35487 USA Sponsored by: Sponsored Division, Jt. Processing and Manufacturing Processing Committee Analysis & Control Modeling Organizers: Program Materials Processing in the Computer in Processing Materials Instruction Computer Aided Age III:

WEDNESDAY PM 171 tions hadminor defects inthesurfacesuchas“hot tears”.Slagaddi- bottomless water-cooled coppercrucible,without slag(CaF2)addi- Continuous ingotsproducedbycold-wall inductionmelting,utilizinga ing ratherthancurrentbatchpractices suchasvacuumarcremelting. and continuouscastingoftitanium barsusingcold-wallinductionmelt- been investigatingameanstoform usefulwroughtproductsbydirect TheAlbanyResearchCenterof theU.S.DepartmentofEnergyhas USA DoE, Matls.Conserv. Div., 1450QueenAve. SW, Albany, OR 97321 Queen Ave. S.W., Albany, OR97321USA; Turner Edward R.Argetsinger 4V Alloys Comparison ofInductionSlagMeltedandCommercialTi-6Al- 2:50 PM reproduced detailsofthepoolshape. superalloy meltingindicatelargeliquidvolumes,buthavenot yet to dateusingboundaryconditionsofthesametypeasreported for conditions insuchVAR cases.Axisymmetric‘2-1/2D’simulationsrun simulation iscrucialtomakingrealisticpredictionsaboutthermal values. Theseresultssuggestthatajudiciousmixofexperimentand ingot axis(asrequiredbyexperiment)forquiteplausibleparameter flow downthepoolsidewalltocasesdominatedbyflows is operating,thesimulatedflowscanchangefromcasesdominatedby velop fullstrengthstirringmagneticinductionBswhenthefurnacearc tion ofarccurrententeringpoolsurface.Ifsolenoidalwindingsde- are modelturbulenceintensity, coefficientofthermalexpansion,frac- which arenotestablishedbyindependentmeasurement.Amongthese siderable careisnecessaryinchoosingthoseparametersoftheprocess experimentally establishedsolid/liquidboundariesfortheabove,con- averaged fieldsandnon-uniformstirring.Inseekingtosimulatethe netic fieldsisclearlyevident;magneticprobedatashownon-zerotime production ingot);the“steering”ofVAR arcbythestirringmag- no “hot-topping”powercut-backwasused,asitwouldhavebeenfora served: theingotisoverhalfliquidatpower-offfromfullpower(i.e., simulation oftheVAR of36"Ti-6-4 ingots,thefollowingwereob- priate thermalandelectricalboundaryconditionsforthenumerical Inexperimentsconductedtoestablish,amongotherthings,appro- Ave., P.O. Box5030,Monroe,NC28111-5030 USA NM 87185-0603USA; 3 E. Ave., Livermore,CA94551-0969USA; Williamson in Simulations Lorentz Force inIndustrialScaleVAR: ParameterSensitivity Ti-6V-Al underElectromagneticStirringandMeltCurrent 2:25 PM eration. Resultsofthemodelarepresentedanddiscussed. dicted beforeperforminganyactualtriplevacuumarcremeltingop- element repartitionvariesalongthelength,canbequantitativelypre- sated” electrode,whichmeansaninitialelectrodewherethealloying ingot. Moreover,thepotentialinterestofusingaso-called“compen- nary meltsontheintensityofmacrosegregationinfinalthird ample, todeterminetheinfluenceofstirringsequenceprelimi- sition forthenextmeltingoperation.SOLARhasenabled,ex- puted compositionofeachingotaftercoolingastheelectrodecompo- provement hasallowedtosimulateatripleVAR melt,usingthecom- of steels,titaniumandzirconiumalloys.Recently, asignificantim- used withsomesuccesstosimulatepilot-plantandfull-scaleremeltings and theintensityofmacrosegregationiningot.SOLARhasbeen and toallowunderstandthelinkbetweensuchoperatingparameters tion ofthemeltingrateandstirringsequenceduringmelting, tant featureofthemodelisitsabilitytotakeintoaccountanyevolu- then whilesolidificationofthefinalliquidpoolproceeds.Animpor- fects, andsolutetransfer(i.e.macrosegregation)duringthemelting, successively accountingforheattransfer,magnetohydrodynamicef- SOLidification duringArcRemelting)wascontinuouslyimproved,by The transient-statemodelnamedSOLAR(whichstandsfor realized inparticularatCompagnieEuropeenneduZirconiumCEZUS. Ecole desMinesinNancyandappliedtosimulateremeltingoperations AnumericalmodeloftheVAR processhasbeendevelopedatthe Sandia NationalLaboratories,MS0603,P.O. Box5800,Alburquerque, 1 ; : 1 Albany ResearchCenter-DoE,Therm.Treat. Tech., 1450 3 ; R.S.Minisandram Alan D.Hartman : L. A.Bertram 4 1 Allvac, AlleghenyTeledyne Co.,2020Ashcraft ; JeffreyS.Hansen 1 ; KarolK.Schrems 1 4 ; F. Spadafora ; 1 Sandia NationalLaboratories,7011 2 1 2 RMI Titanium Company; ; JackI.Paige Albany ResearchCenter- 2 ; S.N.Kempka 2 ; GordonR.Holcomb 1 ; PaulC. 3 ; R.L. 2 ; from TheALTA Group,JMElectronics,isgratefullyacknowledged. (voltammetric andimpedance)techniques.Sponsorshipoftheresearch gated byspectroscopic(visibleandRaman)electrochemical Hunter process.Thekineticsofmetaldepositionarebeinginvesti- trolyte. ThefeedstockistitaniumspongeproducedbytheKroll or electrorefining metallurgicalgradetitaniuminamoltenchlorideelec- Sputteringtargetsforthemicroelectronicsindustryaremade by Ave., Rm.8-109,Cambridge,MA02139-4307USA Institute ofTechnology, Dept.Matls.Sci.&Eng.,77Massachusetts Electrorefining A SpectroscopicandElectrochemicalStudyofTitanium 4:20 PM ultimately achievebetterdesignandcontroloftheoverallprocess. effect ofprocessparametersoninclusionremovaleffectiveness,and physical phenomenaoccurringintheEBCHRprocess,analyze ments. Themodelcanbeusedtodevelopinsightsintotheunderlying and thepoolshapecomparewellwithexperimentalmeasure- ing atdifferentpowerconditions.Thepredictedsurfacetemperatures lution. ThemodelhasbeenappliedtoanalyzeanEBMhearthoperat- predict theinclusiontrajectoriesandtheirchangeinsizeduetodisso- radiation heattransfer. ALagrangiantracking approachisusedto including temperature-dependentMarangoniandbuoyancyeffects for alltheimportantphysicalphenomenainfluencingprocess, the flowandtemperaturefieldswithinhearth.Themodelaccounts solution ofthemomentum,continuityandenergyequationstopredict The modelusesacontrolvolumemethodforthediscretizationand transfer, phasechange,andthemotionofinclusionsinanEBMhearth. a computationalmodelispresentedforpredictingthefluidflow, heat titanium alloysforcriticalaircraftenginerotatingparts.Inthispaper, ElectronBeamColdHearthRefining(EBCHR)isusedtorefine Drop M87,Cincinnati,OH45215-1988USA Engines, Matls.andProcess.Eng.Dept.,OneNeumannWay, Mail Refining ofTitaniumAlloys Mathematical ModelingoftheElectronBeamColdHearth 3:55 PM surface oftheliquidpool. beam scanningfrequencyonthetransientthermalbehaviorof alpha) intermsoftrajectoryanddissolution,theeffects the historyoflowdensityinclusionsinhearth(suchashard- taken intoaccounttheMarangoniandthermalnaturalconvections, an inertgas,thethermo-hydrodynamicbehaviorofliquidpool the alloyingelementsandreductionoftheselossesbyaddition main resultsobtainedwhicharefocusedon:thevolatilizationlossesof tion kineticsofthelowdensityinclusions.Thepaperdescribes namic andsolutebehaviorofthealloyincoldhearthdissolu- the moleculargasdynamicsofvaporphase,thermo-hydrody- three comprehensivenumericalmodelshavebeensetupconcerning melting ofthetitaniumalloys.Resultingfromthisresearchwork, Beam Meltingprocess,withaparticularemphasisonthecoldhearth Since1991wehaveundertakenacompletestudyoftheElectron Villaroche, Moissy-Cramayel77550France 54042 France; Materiaux Metalliques,EcoledesMines,ParcdeSaurupt,Nancy, Cedex P. Bellot Study andModelingoftheElectronBeamMeltingProcess 3:30 PM 3:15 PMBreak “Are anydetrimentaleffectscausedbyslagaddition?”. chemical, mechanical,andcorrosionattributestoaddressthequestion, pared toacommercialalloyTi-6Al-4Vingotintheareasofphysical, finish. Therefore,aslagmeltedexperimentalalloyingotwascom- tions aslow0.5weightpercentwereusedtoimprovethesurface 1 ; H.Duval : 2 SNECMA, Matls.andProcess.Dept.,Centrede Luis Ortiz 1 ; S.Besse 1 ; DonaldR.Sadoway 2 ; : 1 Laboratoire deScienceetGeniedes Shesh K.Srivatsa 1 ; 1 ; 1 Massachusetts 1 GE Aircraft : J.

WEDNESDAY PM 172 ; : 2 2 2 4.8 H 2 ; R. G. 1 -tritide for 6.8 -tritide for : V. V. Hong V. : V. 0.75 The Vietnam Cen- The Vietnam -Fe. The formation 2 R. S. Chiou α Al : 4.25 University of Nevada, 1 ; with Sn (x=0.24) and Mn Sn (x=0.24) with 2 Laves Phase Hydride x 2 and bcc 2 M Royal Institute of Technology, 1 5-x ; 1 phase forms at intermediate tempera- x Los Alamos National Laboratory, Matl. Laboratory, Los Alamos National 2 H 2 ; Ricardo B. Schwarz 1 The University of Alabama, Metallu. and Matls. Eng., The University of Alabama, Metallu. and Matls. Seshadri Seetharaman 2 ; 1 The University of Alabama, Chem. Eng., Tuscaloosa, AL The University of Alabama, Chem. Eng., Tuscaloosa, 1 ; 2 Pa, the desorption isotherm deviates from the absorption iso- Pa, the desorption isotherm deviates from 3 of the crystalline and amorphous GdFe2Hx phases, phase stability of the crystalline and amorphous GdFe2Hx be discussed. regions, disproportionation of the hydride will 3:30 PM Break 4:00 PM Metallothermic Processing of Nd from NdF3 R. E. Aune crystal into a two-phase mixture of GdH 35487 USA; Tuscaloosa, AL 35487 USA reduction of neodymium Production of neodymium metal by the of NaCl-NaF flux was fluoride with sodium as a reductant in presence using Gibbs energy mini- studied. Process calculations were carried out such as tempera- mization method. The effect of process parameters ture, pressure, salt and feed materials composition on the yield and impurity content of the products were analyzed. The yield of Nd metal increased with an increase in temperature and the fluxing agents and so did the impurity content of the metal. An excellent agreement was obtained between the experimental and the calculated data. The results were also compared with other metallothermic processes for the production of neodymium. 4:30 PM Kinetics Studies of Nitridation of Fe17-Nd2 Alloys Dept. of Metallu., SE-100 44, Stockholm, Sweden; Instit. of Matls. Sci., Dept. of Rare ter for Science and Technology, Hanoi, Vietnam giay, Earth Met., Hoang Quoc Viet-Cau The magnetic properties of Fe-Nd alloys are significantly improved by the introduction of interstitial elements like boron and nitrogen. In the processing of these property optimized magnetic alloys, it is important to have access to the kinetic information regarding the nitrogen uptake by these alloys at the process temperatures. The present work was undertaken to study the kinetics of nitridation of Fe17-Nd2 magnetic alloys in the temperature range 1173-1473 K. Thin plates of the high purity alloy (10 mm diam, initial weight between 207 and 463 mg) were used. The increase in mass of the sample was followed using 1273, 1373 92 unit, as a function of time at 1173, TAG a SETARAM, interactions. Similar decreases in hydrogen pressures were obtained were pressures in hydrogen decreases Similar interactions. LaNi thermally aged studies on from showed 583K also 563K and aging at Thermal substitution. (x=0.4) isotherms that desorption aging, except that of 473K trends as similar were the absorption isotherms at lower H/M values; developed slopes of LaNi Room temperature aging unaffected. a steep slope. isotherms developed that the desorption years showed decay and due to radiolytic aging, helium-3 formed During tritium non-uniform This resulted in in the metal lattice. remained trapped Bragg peaks. the X-ray diffraction lattice which broadened strain in the will be discussed. The thermal aging results 3:00 PM of GdFe Hydrogen Amorphization Dhanesh Chandra School of Mines, Mail Stop Mackay Div., Metallu. and Matls. Eng. USA; 388, Reno, NV 89557 NM 87545 USA Mail Stop G755, Los Alamos, Div., Sci. and Tech. interaction with GdFe of hydrogen have investigated the effect We relatively low Crystalline hydrides are formed at Laves phase alloy. and the reaction is reversible. A GdFe temperatures and pressures, of which is reversible, with a H/M ratio is formed at room temperature, desorption of all the hydrogen from 1.6. However, at this temperature and, for pressures below the hydride is difficult because of slow kinetics 10 therm. An amorphous GdFe for this hydriding reac- tures and pressures. The absorption isotherm transformation is quite unusual in that, as the crystal-to-amorphous of hydrogen. Absorption tion is accompanied by either a gain or a loss is an abrupt decrease in isotherms taken below 475K showed that there the crystalline-to-amor- the hydrogen capacity of the alloy during the absorption isotherms phous hydride phase transformation. Whereas abrupt increase in the taken above 475K showed that there is an temperatures above 525 hydrogen capacity during amorphization. At of the GdFe K, hydrogen absorption causes to the disproportionation Reddy : ; J. 2 Iowa 1 ; Karl A. 1 : 0.5. This pa- ≤ ; J. R. Wermer 1 0.5. These materials ≤ Hydrides and Tritides 0.75 ; Vitalij K. Pecharsky ; Vitalij 1 Al ; H. Mandalia 1 4.25 University of Nevada, Metallu. and Matls. 1 ; D. Clare 1 Renato G. Bautista, University of Bautista, University Renato G. showed that the plateau pressure decreases ; 3 -tritide at room temperature. The hydrogen Room: Lincoln E Convention Center Location: Opryland 0.75 0.75 -hydride was performed in the range of 473 to Al Danesh Chandra, University of Nevada, Danesh Chandra, University Al 0.75 Westinghouse Savannah River Company, Savannah Savannah River Company, Westinghouse 4.25 3 Light Metals Division, Reactive Metals Division, Reactive Light Metals Al 4.25 type hydrides are important for applications such as 4.25 5 ; Alexandria O. Pecharsky 1 ; W. N. Cathey ; W. 1 ; W. C. Mosley ; W. 3 Los Alamos National Laboratory, Mail Stop C 348, Los Alamos, Los Alamos National Laboratory, 2 were not due to metallurgical heat treatment but because of hydrogen Eng. Div., Mackay School of Mines, Mail Stop 388, Reno, NV 89557 Mackay School of Mines, Mail Stop 388, Reno, NV Eng. Div., USA; D. Chandra NM 87545 USA; Aiken, SC 29808 USA Ctr., River Tech. The LaNi 583K, and LaNi aging experiments performed at 473K, showed a rapid initial decrease in hydrogen pressure followed by gradual decreases in pressure; the initial hydrogen pressure was 1930 kPa. Isotherms taken at 389K, after hydrogen thermal aging at 473K, showed that the desorption pressure of the isotherm decreased by approximately 45 kPa. Vacuum annealing of LaNi hydrogen/tritium storage systems and others. In this study, thermal hydrogen/tritium storage systems and others. In this study, aging of LaNi S. Holder Gschneidner to overcome these and per will discuss the development of processes material which exhibits other difficulties. Kilogram quantities of the the giant magnetocaloric effect have been prepared. The resultant magnetocaloric effect is slightly less than that obtained by arc-melting high purity Gd metal with Si and Ge. Supported by US DOE, Office of of Mats. Scis., under Contract No. W- Sciences, Div. Basic Energy 7405-ENG-82. 2:30 PM Thermal Aging Studies of LaNi 2:00 PM Refriger- The Preparation of Gd//5(Si//x/Ge//1-x/)//4/Magnetic Metal ant Materials from Commercial Gadolinium Wednesday PM Wednesday Nevada-Reno, Department of Chemical and Metal Engineer- Nevada-Reno, Department USA; Brajendra Mishra, Colorado ing, Reno, NV 89557-0136 Institute for Extractive Metals, School of Mines, Kroll USA Golden, CO 80401-1887 March 15, 2000 Session Chairs: Reno, NV 89557 USA; Seshadri Metall. and Matls. Eng., Dept. of Institute of Technology, Seetharaman, Royal Metallu., Stockholm SE-100 44 Sweden Ames, IA 50011-3020 Ames Lab., 255 Spedding, State University, USA giant magnetocaloric ef- About three years ago we discovered the x fect materials Gd//5/(Si//x/Ge//1-x/)//4/, where alloys for a wide have great promise as useful magnetic refrigerant supermarket chillers, range of applications-building air conditioning, climate control, etc. To frozen food processing plants, automotive by arc-melting using high date most of the samples have been prepared The sample sizes are of purity (99.8 at.%) Ames Laboratory Gd metal. is to be realized, one will the order of 50g or less. If commercialization (95 to 98 at.% pure with need to use inexpensive commercial grade Gd which can be used major impurities of O and C) and a melting process the Gd//5/(Si//x/Ge//1-x/)/ to prepare large quantities (1kg or larger) of found that carbon impurities are detrimental by prevent- /4/alloys. We thus destroy the giant ing the formation of the monoclinic phase and x magnetocaloric effect in Gd//5/(Si//x/Ge//1-x/)//4/for Sponsored by: Sponsored Committee Program Organizers: Rare Earths and Actinides; Science Actinides; and Earths Rare Rare IV: and Applications Technology II: Processing Earths

WEDNESDAY PM 173 Anderson ing performanceinmetalmatrix composites. point outunder-exploitedopportunities forreducingcostandimprov- slurries, anddirectdeposition).From thisanattemptwillbemadeto composite (solid-consolidation,reaction processing,solidificationof sentation willconsiderthelimiting casesofhowonemightcreatea when designingacompositeand its manufacturingprocess.Thispre- the compositeandprocessdesignermustbeconsideredtogether to nameafew. Insomewaytheseissuescanworkeitherwithoragainst ture, thermodynamiccompatibility, mismatchinthermalexpansion dispersion ofreinforcement,scalereinforcementandmicrostruc- through processingcanquicklyemerge.Concernsinclude:uniform posite properties,alistoftechnicalissuesthatmustbedealtwith Ifonestartsbyconsideringtheoptimizationofmetalmatrixcom- Matls. Sci.andEng.,2041CollegeRd.,Columbus,OH43210USA trix Composites Status, IssuesandOpportunitiesinProcessingofMetalMa- 2:00 PMInvited National Laboratory, Ames,IA50011-3020 USA Group, Murrysville,PA 15668USA;JamesC.Foley, Ames Session Chairs: March 15,2000 Wednesday PM USA Aluminum ConsultantsGroupInc.,Murrysville,PA 15668 Engineering, Cleveland,OH44106USA;Warren H.Hunt, Reserve University, DepartmentofMaterialsScienceand Program Organizers: Committee; Young LeadersCommittee Sponsored by: of MMCs Metal MatrixComposites:Processing Research andDevelopmentEffortson under contractW-7405-Eng-82. rials ScienceDivisionofDOE/BESprovidedfundsforthisresearch material toperformasabatteryelectrodewillbedescribed.TheMate- results pertainingtotheeffectcoatinghasonabilityof lasting Ni/MHbatteries.Themethodusedtocreatethiscoatingand consistent passivationlayerwouldenablemanufacturingoflonger fluoride (LaF3)layeratthesurfaceofpowders.Developmenta material withnitrogentrifluoridegas(NF3),creatingalanthanum developed toreactthelanthanumcontainedwithinmetalhydride potassium hydroxide(KOH)electrolytesolution.Amethodhasbeen primary causeofthecorrosionisinteractionwithcaustic (Ni/MH) rechargeablebatteriesisacommoncauseoffailure.The Corrosionofthemetalhydrideelectrodeinnickel-metal and Cer., Ames,IA50011 USA Gaseous FluorinationofMetalHydrides 5:00 PM impurity onthereactionratearediscussed. tion wasevaluated.Thereactionmechanismandtheeffectofoxygen energy fortheratecontrollingstepduringinitialstagesofnitrida- rity haveastronginfluenceonthereactionkinetics.Theactivation the reactionrateduetoformationofproductlayer. Oxygenimpu- temperature, followedbyarapidnitridationperiod,andslowdownin oxygen was<10-23bar. Theincubationperiodwasafunctionof 25%(vol%). Nitrogengaswaspurifiedsothatthepartialpressureof and 1473Knitrogenpartialpressuresof100%,75%,50%, 1 ; J.C.Foley : Joint ASM-MSCTS/TMS-SMDComposites Warren H.Hunt,AluminumConsultants Glenn S.Daehn 1 ; Location: OprylandConventionCenter Room: BayouA 1 John J.Lewandowski,CaseWestern Iowa StateUniversity, AmesLab.,Metallu. 1 ; 1 The OhioStateUniversity, : M. L.Anderson 1 ; I.E. Al Thermodynamics ofIn-SituReactionbetweenTiO2andPure 2:50 PM Eng-82 isgratefullyacknowledged. development grantandDOE-BES-DMSundercontractno.W-7405- technique. SupportfromanAmesLaboratorydirectedresearchand can nowbedirectlyobservedasafunctionoftimewiththenew obtained resultsdemonstratesthatdensityandtheextentofsintering thermal analysisandmechanicaltestingtechniques.Comparisonof were examinedwithstandardmetallography, densitymeasurement, tively wereexaminedwiththenewmethod.Inaddition,samples sintering. SamplesofAl-4wt%Cu+10%,20%and30%SiCrespec- velocity ofanultrasonictonebursttravelingthroughasampleduring consists ofahightemperatureEMAT tomeasuretheamplitudeand structive evaluationmethodtocharacterizesintering.Thenew at theDepartmentofEnergy’s AmesLaboratoryisanin-situnonde- metal matrixcomposites.Onesuchtechnologythatisbeingdeveloped the developmentoftechnologiestoenableproductionlow-cost Renewedinterestintheareaofmetalmatrixcompositeshasspurred Dev., Ames,IA50011 USA Sintering ofMetalMatrixComposites In-Situ NondestructiveEvaluationMethodforCharacterizing 2:30 PM 3:30 PMBreak ZrAl3/1N90 compositeis2~3mm. tion clarifiesthatthefinefiber should beZrAl3andgrainsizeof tion toabout200%at0.1/secand at913K.TEMmicro-characteriza- Hot rollingthecompositeafterextrusion increasesthetotalelonga- total elongationofabout150%atthestrainrate0.1/sec923K. 1N90 composite(Vf=0.05)exhibitedanmvaluemorethan0.3and a extruded withtheextrusionratioof44:1at823K.TheZrAl3/ were 0.05,0.10and0.15.SinteredZrAl3/1N90Alcomposites tion ofZrO2withaluminum.Thevolumefractionsselected pure aluminumcompositewithfiberdiameterlessthan1mmbyreac- 285MPa for20minutes.ThisproducedZrAl3fiberreinforced1N90 aluminum powder(1N90andsinteredat823Kunderthepressure of NanoZrO2particlesusedasreinforcementweremixedwithpure search Institute,3-4-41Rokuban-cho,Atsuta-ku,Nagoya,Japan Technology, Harbin150001PRC; Nagoya, 1-1Hirate-cho,Nagoya462-8150Japan; Lin Geng forced AluminumComposites High StrainRateSuperplasticityofIn-SituZrAl3FiberRein- 3:10 PM contract No.96PR07712-00. Office ofNavalResearchandcoordinatedbyDr. S.Fishman,under design ofquantitativeexperiments.Thisworkissupportedbythe up toveryhightemperaturescreatinginthesametimebasefor Al3Ti, Al2O3+Ti3Al+TiAl,andTiAlAl3Tiphaseregions and isshowingthestabilityofAl2O3+Ti3Al,Al2O3+TiAl, the calculatedAl-TiO2pseudo-binaryphasediagramwas Al +Al3TiAl2O3three-phaseequilibriumispossible.Furthermore equilibrium, orTi3Al+Al2O3alpha-Ti,TiAlAl2O3,and either Ti3Al+Al2O3,TiAlandAl3TiAl2O3two-phase Isothermal Ti-Al-Ocrosssectionsat800 pounds Ti3Al,TiAl,Al3Tiispossiblewithinalargetemperaturerange. to Al2O3andtheformationoftitaniumaluminumintermetalliccom- Al3Ti). ThermodynamiccalculationsshowthatthereductionofTiO2 basis forthein-situformationofAl2O3reinforced(Ti3Al,TiAl, completion. Thispresentationsummarizesthethermodynamicdesign and fabricatingcompositesthatallowthereactionstoprogress cally stablesystemsbyrecognizingtheinevitabilityofthesereactions Al-Graphite, etc.Howeveritispossibletofabricatethermodynami- forts havebeenmadetoavoidmatrix-reinforcementreactionAl-SiC, considered deleteriousinthefabricationofMMC’s. Indeedmajoref- Thereactionbetweenthematrixandreinforcementisnormally Matls. Eng.Dept.,204OlinHall,Clemson,SC29634USA K. Rehbein : Iulian Gheorghe 2 ; SumitoKojima 1 ; 1 Ames Laboratory, Metallu.andCera.Pgm.,122Metals 1 ; HenryJ.Rack 3 ; 1 National IndustrialResearchInstituteof : 3 Nagoya MunicipalIndustrialRe- Tsunemichi Imai 1 ; 1 ° Clemson University, Cer. & C and1100 : James C.Foley 2 Harbin Instituteof 1 ° ; JianfuMao C indicatethat 1 ; David 2 ;

WEDNESDAY PM 174 : MMC is 3 O 2 ; Enrique J. Lawrence E. 1 Michigan State Michigan 1 : ; 1 Qingzhou Xu : The University of Texas, Metallu. The University of Texas, 1 ; ; Kali Mukherjee ; Kali 1 1 and Aluminum A339-10% SiC 3 ; Jong-Kook Park ; Jong-Kook 1 O ; Elizabeth A. Trillo 2 1 University of California, Chem. and Biochem. Eng. and particles are added to aluminum alloy 6061, the initial particles are added to aluminum alloy 6061, 1 3 O ; 2 1 /Al-A339-10% SiC system which is facilitated by differential ; Ying Li ; Ying . In each case the hard particles are homogeneously stirred into . In each case the hard particles are homogeneously 3 1 3 O O 2 2 Lavernia Murr by 33% at 20% yield stress and hardness are increased; nominally + 20% Al particle additions. When aluminum alloy 6061 recrystallized. Examina- the weld zone, which has been dynamically associated with FSW in tion and comparison of the microstructures of the technological these systems not only provides some examples MMC systems, potential for FSW in joining complex and dissimilar flow phenomena in but also the opportunity to examine particulate This is especially no- solid-state, extreme deformation processing. in the Al-6061-20% table in the examination of intercalated flow Al Implications for friction processing etching in optical metallography. such as friction extrusion reforming of previously formed MMC are also presented. Research supported in part by a NASA Cooperative Agreement (NCC8-137) and by a General Services Administration grant. 5:00 PM Distribution of Reinforcing Particles in MMCs Produced by Spray Atomization and Deposition Matls. Sci., Irvine, CA 92697 USA Aluminum-based MMCs are synthesized by spray atomization and deposition combined with a co-injection method or a stirring method. The present work attempts to provide insight into the distribution of reinforcing particle in the different processing approaches. For the co-injection method, it is easy to incorporate SiC particles into the spray of metallic droplets, but the aggregation of SiC particles often is very severe as a result of the non-uniform spatial distribution of particles which come from several isolated injectors. For the stirring method, it is difficult to add SiC particles into aluminum liquid due to the effect of surface tension. However, the particle distribution is very uniform in the matrix since MMCs are generated through the accumu- the lation of individual droplets containing SiC particles. Additionally, University, Matls. Sci. & Mech., High Energy Laser Process. Lab., Process. Laser High Energy & Mech., Matls. Sci. University, MI 48824 USA East Lansing, have composites (PRMMC’s) reinforced metal matrix Particulate over mono- potential advantages interest due to the received strong However, engineering applications. alloys in numerous lithic metal mismatch stresses, due to a retain high levels of residual the PRMMC’s ceramic rein- (CTE), between a of thermal expansion of coefficient matrix. The residual stresses result in surface forcement and a metal limits structural application of metal matrix crack initiation, which processing (LSP) is a unique way to locally composites. Laser shock profile on a metal matrix composite. By using alter the residual stress can generate LSP density, with high energy a very short laser pulse high-pressure stress wave propagation. surface plasma that induces be relieved on the surface by incident shock The residual stresses can by the confined expansion of the high- waves, which are generated excimer laser is used for the pulsed laser irra- pressure plasma. A KrF processed alumina/6061 aluminum composite. diation, on a stir-melt is used for measurements of the residual stresses. An x-ray diffractometer 4:40 PM of Metal-Matrix Composites: Aluminum Friction-Stir Welding 6061-20% Al El Paso, TX 79968-0520 University Ave., and Matls. Eng., 500 W. USA dynamic Friction-stir welding (FSW) involves deformation-induced In the join- flow. recrystallization to facilitate solid-state, superplastic areas cause reducing of aluminum alloys such as 6061, heat affected 50%, and strategies to tions in residual strength and hardness of nearly successful. However, reduce this behavior have been only partially when Al hardness just outside the friction-stir welded, there is a reduction in 6061 Al, the minimum weld zone of 58%. However, in contrast to results are obtained for residual hardness is reduced by only 9%. Similar Cu, Mg, and Ni, 0.5% the FSW of aluminum alloy A339 (11% Si, 1% to the Al 6061 + 20% Fe, balance Al) + 10% SiC; and this MMC welded Al 4:20 PM 4:20 Composites Metal Matrix on Shock Processing Laser Excimer James G. Cross James ; 2 C, the ° University of Wis- University C. At 1025 1 ° ; David C. Dunand 1 ; 1 C and 715 ° T. A. Venkatesh T. : Northwestern University, Matls. Sci. and Northwestern University, 2 C, the NiAl-W composites exhibited insig- ; John H. Perepezko ; John ° 1 Joon Sik Park Joon : MIT, Matls. Sci. and Eng., Rm. 8-139, 77 Massachusetts Ave., Cam- Matls. Sci. and Eng., Rm. 8-139, 77 Massachusetts Ave., MIT, NiAl-W composites exhibited three stage creep behavior with distinct and tertiary creep, where the composite creep- secondary, primary, remained constant, and increased rap- rate decreased monotonically, At 715 respectively. idly, Eng., 2225 N Campus Dr., MLSB 1123, Evanston, IL 60208 USA MLSB 1123, Eng., 2225 N Campus Dr., and composite NiAl was Reactive infiltration processing of bulk nickel. Inhomogeneous investigated with powder and wire preforms of preforms because microstructures were often obtained with powder and irregular in- their high surface-to-volume ratio, low permeability, and reaction. Homog- filtration paths lead to simultaneous infiltration preforms which had a enous NiAl could be obtained with nickel-wire and regular infil- lower surface-to-volume ratio, higher permeability, before the onset of tration paths, because infiltration was completed (W) and sapphire fi- reaction. Composites with continuous tungsten bers were also successfully fabricated by reactive infiltration, while composites with molybdenum particulates and short-fibers showed significant dissolution in NiAl. The high-temperature uni-axial compression creep behavior of uni-directionally reinforced continuous fiber composite materials was investigated using NiAl-W as a model system for the case where both the NiAl matrix and the tungsten fiber under- went plastic deformation by creep. The creep behavior of the constituents NiAl and W and NiAl composites reinforced with 5-20 volume% W was characterized at 1025 nificant primary and tertiary creep but significant secondary creep. primary and secondary creep were characterized by Microstructurally, pure uni-axial compression of tungsten fibers while brooming, bulging, buckling, and kinking were four fiber deformation modes that contributed to tertiary creep. The observed secondary creep behavior correlated well with the rule-of-mixtures isostrain model developed for composites where both phases undergo creep deformation while new models were developed for the composite primary and tertiary creep and were correlated reasonably well with the experimental results. bridge, MA 02139 USA; 1 3:40 PM 3:40 Composite Temperature for High Strategies Design Interface Systems Madi- Ave., Univ. Eng., 1509 Sci. & Dept. of Matls. consin-Madison, USA son, WI 53706 reproducible factors controlling understanding of the basic A clear application. the high temperature is critical for composite processing higher order represent ternary or composite materials Since the usual materi- potential reinforced ternary systems including systems, model to provide been examined in order B4C and SiC phases have als such as the composite materials design. One attractive effective strategies for is stable phase combination (i.e. compatibility) approach to obtain the phase combination by using controlled interface to produce the desired synthesis. For example, if the reaction reaction to achieve in-situ materials does not yield a preferred between matrix and reinforcement the diffusion path can be biased to produce phase combination, the An effective approach to control the reac- desired phase combination. pathway by adding an extra component tion products and diffusion has been developed and investigated based upon layer as a kinetic bias semi-empirical database. The growth kinetics flux calculations and a and the effect of the biasing layer during inter- of the product phases be presented for Ni/SiC and TiSi2/TiAl systems. diffusion reaction will the bias includes not only a control over The influence of the kinetic over the microstruc- phase selection and sequencing, but also a control reactions. An tural morphology that develops during interdiffusional of component chemi- analysis of the diffusional interactions in terms guidance for reaction cal potential variations provides useful general an interface design strat- path control and the limiting kinetics. With kinetic biasing to include egy based upon a diffusion path directed by the resulting in-situ thermodynamically stable phase combinations, to yield robust com- synthesis offers a self-healing of internal damage is grate- posite performance. The support of ONR (N00014-92-J-1554) fully acknowledged. 4:00 PM Creep of Reactive Infiltration Processing and Compression NiAl and NiAl Composites

WEDNESDAY PM 175 polishing, theywill beappliedtomanymachineelements. Firstly, we scribed above,if as-depositeddiamondcoatingscan beusedwithout coatings consumesmuchtimeand money. Fromapoint ofviewde- not manyuses,exceptforcutting tools,becausepolishingdiamond a lowfrictioncoefficientand wearrate.Nevertheless,theyhave mond coatingshavemanyexcellent properties,suchashighhardness, coatings bychemicalvapordeposition (CVD)wascompleted.Dia- Almosttwentyyearshavepast sincethesynthesisofdiamond Japan Kenkyuzikkento, 2-12-1O-okayamaMeguro-ku,Tokyo 152-8552 kyo InstituteofTechnology, Dept.ofMech.Eng.,204Ishikawadai cation toaMachineElement Tribological Properties ofDiamondCoatingsandTheirAppli- 2:20 PM processed alloylayerphasesandproperties. ness andwear. Resultsshowthepossibilityofpredictinglasersurface higher compositions).Thisprovidedthebasisforestimationsofhard- (for lowercompositions)andtheFe,NiCrphasediagrams calculated andthephasesevaluatedbaseduponShaefflerdiagram final alloycomposition.Nickelandchromiumequivalentswerethen sitional mixparameterswereemployedtopredictmeltdepthsand tests. Analyticalcalculationsusingprocessingparametersandcompo- fraction, SEMandmicroprobecompositionaldeterminationwear consisted ofmetallographicobservations,hardnesstests,x-raydif- therefore control,themetallurgicalproperties.Metallurgicalanalysis four differentenergylevelstoinvestigatetheabilitypredict,and chromium andchromium/nickelpowderslasersurfaceprocessedat Two lowcarbonsteelswerecoatedwithcompositionalmixes of Goethert Pkwy., Tullahoma, TN37388USA versity ofTennessee SpaceInstitute,Ctr. forLaserApp.MS24,B.H. Narendra B.Dahotre ser SurfaceProcessedLowCarbonSteels Prediction andEvaluationofMechanicalProperties ofTwo La- 2:00 PM Ground, MD21005-5069USA Weapons &Matls.Rsrch.Directorate,AberdeenProving USA; JohnD.Demaree,ArmyResearchLaboratory, Adv. Coat.andSurf.Eng.Lab.,Golden,CO80401-1887 Session Chairs: March 15,2000 Wednesday PM Materials Engineering,Golden,CO80401USA rado SchoolofMines,DepartmentMetallurgyand Metals, Golden,CO80401-1887USA;JohnMoore,Colo- Colorado SchoolofMines,KrollInstituteforExtractive tions, Tullahoma,TN37388USA;BrajendraMishra, sity ofTennessee SpaceInstitute,CenterforLaserApplica- ing, Orlando,FL32816USA;NarendraB.Dahotre,Univer- Center andMechanical,MaterialsAerospaceEngineer- Florida, AdvancedMaterialsProcessingandAnalysis Program Organizers: Division, SurfaceEngineeringCommittee Sponsored by: ation (PE)-II ence I:Coating/FilmsPropertiesEvalu- Surface EngineeringinMaterialsSci- reinforcing particlesareanalyzedtheoretically. cation interfaceaswelltheirinfluenceonthefinaldistributionof interactions betweenSiCparticlesandthemovingsolid-liquidsolidifi- Materials ProcessingandManufacturing John J.Moore,ColoradoSchoolofMines, 1 ; JohnA.Hopkins Location: OprylandConventionCenter Room: CanalB Sudipta Seal,UniversityofCentral : Ryo Nawata 1 ; T. DwayneMcCay 1 : ; HitoshiTokura Mary HelenMcCay 1 ; 1 ; 1 Uni- 1 To- 1 ; 850 havior ofTi-Al-N ThinFilms Effect ofDepositionTemperature onthePhysico-ChemicalBe- 3:00 PM dress specificindustrialproblemsarealsodiscussed. tial applicationsforlasersurfacetreatmentandTiCcoatingstoad- with thepossiblereasonfortheirbehaviorarepresented.Thepoten- dispersive spectrometry(EDS)theeffectivenessofcoatingsalong steel inmoltenaluminum.Basedonmetallographicstudiesandenergy- contribute significantlytowardsimprovingthecorrosionbehaviorof steel coatedwithTiC.Thefinergrainsizeandlasershotpeening significant improvementincorrosionresistancewasachievedforH13 H13 diesteelinliquidaluminumalloyA390havebeeninvestigated.A different lasersurfacetreatmentparametersoncorrosionbehaviorof sion conditions.TheeffectsofgrainsizetheTiCcoatingand surface treatedandTiClasercoatedH13steelunderacceleratedcorro- presents theresultsofastudyinvolvingisothermalcorrosionlaser (103-108 Ks-1),andproductionofmetastablephases.Thispaper due toitsflexibility, depthofpenetration,highsolidificationrates gies beingpresentlyused,lasersurfaceengineeringisveryattractive dies. Amongstthedifferentsurfacetreatmentsandcoatingtechnolo- nature titaniumcarbideisasuitablecandidateforcoatingdie-casting the die.Duetoitsexcellentcorrosionandhighlyabrasionresistant life. Thesecoatingsreducethemoltenmetalcorrosionanderosionto ramic coatingsandsurfacetreatmentstoextendthedie-castingdie Thereisagrowinginterestinapplicationofintermetallicandce- 78238 USA USA; Matls. andAdv. Process.,321MinesBldg.,Moscow, ID83844-3026 Coated H13DieSteel Study ofCorrosionBehaviorLaserGlazedandTiC 2:40 PM ings toamachineelementsuchasbearings. Secondly, makinguseofthisphenomenon,weapplieddiamondcoat- (SEM), thechangeofsurfacemorphologycausedthisphenomenon. From observationofthesurfacebyscanningelectronmicroscopy that as-depositeddiamondcoatingscanbeusedwithoutpolishing. several mechanismshavebeenproposed.Thisphenomenonsuggests rapidly. Somestudiesonthisphenomenonhavebeenreportedand mond coatings,weconfirmedthatthefrictioncoefficientdecreased as-deposited diamondcoatingswererubbedagainstdia- and stainlesssteeltitaniumdisksindifferentenvironments.When disks. Diamondcoatedpinswererubbedagainstdiamonddisk search. Diamondcoatingsweredepositedoncementedcarbidepinsand examined tribologicalpropertiesofdiamondcoatingsasthebasicre- 3:20 PMBreak films indetailbyusingSEM,XRD, AESandXPS. ture, mechanicalandsurfacechemical propertiesof(Ti,Al)Nthin corrosion resistance,itseemstobe desirabletostudythecrystalstruc- with respecttohardness,wearresistance, oxidationresistanceand oxidized inaverticalfused-silicatubefurnacepureO fected bythedepositiontemperatures.Theasdepositedfilmswere magnetron sputtering.Bothstructureandmorphologyaregreatly af- 316SS substratesunderambientandliquidnitrogentemperaturesby dc- mal stability. Inthisstudy, (Ti,Al)N coatings weredepositedonto microhardness anddensemicrostructure,butalsobytheirgreaterther- In contrast,(Ti,Al)Ncoatingsarecharacterizednotonlybyhigh due tothefact,thatitoxidizesrapidlyattemperaturesabove500 The majorconcernofusingTiNinhigh-temperatureapplications is a promisingalternativecandidatetothewidelyusedtitaniumnitride. tool technology. Ternary (Ti,Al)N witha1:1Ti:Al ratioseemsto be Nitridebasedhardcoatingsareofprimeinterestintoday’s cutting TN 37388USA Dept. ofMatls.Sci.&Eng.,MS-24,B.H.GoethertPkwy., Tullahoma, USA; Central Florida,Elect.andComp.Eng.Dept.,Orlando,FL32816 AMPAC &MMAE,Eng.381,Orlando,FL32816USA; Jimenez Govindaraju ° C for3.5and7.5hours.Because oftheiroutstandingproperties 3 2 University ofTennessee SpaceInstitute,Ctr. forLaserApp., Karta Technology Inc.,1892Grandstand,SanAntonio,TX 1 ; K.Sundaram 2 ; F. H.(Sam)Froes 2 ; N.Dahotre : Daiel Pirzada : 1 ; S. Seal 3 ; 1 University ofIdaho,Instit.for 1 University ofCentralFlorida, 1 1 ; A.Kale ; E.G.Baburaj 1 ; V. Desai 2 atmosphereat 2 University of 1 ; M.R. 1 ; D. ° C.

WEDNESDAY PM 176 Engi- Colo- 1 2 Tatsuki ; 2 : . The compo- . The 2 ; J. Zhou 2 ; B. Mishra 1 Rajiv S. Mishra, University of F. M. Kustas F. Room: Polk A/B Location: Opryland Convention Center : Ruslan Z. Valiev, Institute of Physics of Ruslan Z. Valiev, Materials Processing and Manufacturing National Industrial Research Institute of Nagoya, Superplastic 1 ; 1 2:00 PM Invited Inhibition of Ceramic/Ceramic Nanocomposites Creep Ohji Nanoscience Lab., Hirate-cho, Kita-ku, Nagoya 462-8510 Japan Ultrafine Grained Materials: Mechanical Behavior and II Strengthening Mechanisms: Sponsored by: at 75keV with a dose range of 1.0 ~ 8.0x1017 ions/cm of 1.0 ~ 8.0x1017 dose range with a at 75keV and implanted as-deposited structure of and crystallographic sition spectroscopy photoelectron by X-ray characterized were TiN coating was employed A nanoindentor X-ray diffraction. and Glancing-angle tests were Ball-on-disc wear the hardness of TiN coatings. to measure and implanted of as-deposited to evaluate wear resistance carried out ion implan- tests showed that boron The results of wear TiN coatings. resistance of of the wear in a significant improvement tation resulted TiN coatings. 4:55 PM Carbide & Metal Between Various Performance Comparison Coatings Co-Sputtered CO 80134-4702 USA; Box 4702, Parker, neered Coatings, P.O. Dept. of Metallu. & Matls. Eng., Golden, CO rado School of Mines, 80401 USA if excellent potential for wear applications Carbide coatings have and durability can be increased. Addi- their toughness, wear resistance, is a well know method to increase tough- tion of metals to ceramics by traditional cermet (ceramic/metal) bulk ma- ness, as demonstrated carbide Using a similar approach, several different terials technology. were fabricated in coating-form using bias- & metal cermet systems co-sputtering from a single target. Cer- assisted unbalanced magnetron evaluation included met systems that were fabricated for subsequent titanium carbide (TiC) & boron carbide (B4C) & molybdenum (Mo), car- TiC/chromium & W, diboride (TiB2) tungsten (W), TiC/titanium (SiC) & metals. Coating bide (Cr3C2) & metals, and silicon carbide (by XRD) were mea- elemental composition (by XPS) and structure and wear tests were per- sured, while scratch adhesion, microhardness, the different cer- formed to enable performance comparisons between were measured for dif- met systems. In general, unique performances system exhibits ferent cermet systems. For example, the TiC&W against WC-Co at an excellent wear resistance (non-measurable wear B4C & Mo system has initial stress of 1.3 GPa (192 ksi), whereas the for the different extremely high hardness (>5000 HKN). Reasons and candidate appli- performances of the cermet systems are proposed partially discussed. Work cations for these unique cermet coatings are grant under the Entrepreneur’s supported by a Department of Energy Program. Assistance (ETAP) Technical Shaping and Division, Powder Metallurgy Committee, Forming Committee Program Organizers: Missouri, Metallurgical Engineering, Rolla, MO 65409-0340 Materials Director- Laboratory, USA; S. L. Semiatin, Wright ate, Dayton, OH 45440 USA; C. Suryanarayana, Colorado School of Mines, Department of Metal and Materials Engineering, Golden, CO 80401 USA; Naresh Thadhani, School of Materials of Technology, Institute Georgia Science and Engineering, Atlanta, GA 30332-0245 USA PM Wednesday March 15, 2000 Session Chair: Advanced Materials, Ufa 450000 Russia : ; ; ) 2 1 γ Jun : ; B. C. and 2 (ε ; David P. 1 ; N. Nagasaka 1 ; K. Marchev Ebara Research Com- 1 2 Svetlana M. Zemskova : ; N. Iwamoto 1 ; Kevin M. Cooley Shanghai Jiao Tong University, Shanghai Jiao Tong 1 1 ; R. Hidalgo ; 1 1 ; K. Fujita 1 ; M. Landis 1 ; Yaohe Zhou ; Yaohe 1 Saint Gobain Industrial Ceramics Inc., Norton Dia- Industrial Ceramics Inc., Saint Gobain 2 ; Matthew K. Ferber 1 Ion Engineering Research Institute Corporation, 2-8-1, 1 ; Y. Matusmoto ; Y. 1 R. Vallerio ; Northeastern University, Barnett Instit. and Dept. of Chem., Dept. of Instit. and Barnett University, Northeastern Oak Ridge National Laboratory, Met. and Cer., P.O. Box P.O. Met. and Cer., Oak Ridge National Laboratory, 3 1 1 : ; ; 1 1 ; Sun Baode Li 1 Ebara Corporation, 20-1 Nakasode, Sodegaura, Chiba-ken 299-0296 Japan TiN coatings were deposited on SUS420J2 steel substrates by cathodic arc evaporation. Boron ions were implanted into TiN coatings 3 Tsuda-yamate, Hirakata, Osaka 573-0128 Japan; Tsuda-yamate, Yao-Can Zhu Yao-Can Kataoka T. pany Limited, 2-1,Honfuzisawa 4-chome, Fujisawa 251-8502 Japan; 2008, 1 Bethel Valley Rd., Oak Ridge, TN 37831-6063 USA 2008, 1 Bethel Valley thin (3-5mm) chemical Recently it has been demonstrated that vapor deposited (CVD) mullite 3Al2O3x2SiO2 provides excellent oxidation protection for Si3N4 and SiC in high-pressure steam. However, CVD mullite microstructure and composition may substantially influence the coating properties. It was found that the Al:Si ratio in CVD coatings with “mullite-like” structures can be varied from 1:1 up to 9:1 depending on the deposition conditions. The present investigation is aimed at development of CVD parameters for fabrication of dense, uniform, crystalline mullite coatings with controlled Al:Si ratios. The mechanical properties of as-coated Si3N4 specimens were tested by four-point bending and compared with the properties of non-coated material. The effect of mullite Al:Si ratio on coating microstructure, mechanical properties and oxidation resistance was evaluated. 4:35 PM Influence of Boron Ion Implantation on the Mechanical Prop- erties of TiN Coatings Deposited by Cathodic Arc Evaporation Stinton James A. Haynes Giessen treatments. present after higher temperature 3:55 PM Cr3C2-NiCr Detonation Spray Coating Behavior of Wear Wang Eng., Shanghai, China School of Matls. Sci. & the surface charac- Coatings can be applied to surfaces to improve are widely used in tribo- teristics over those of the bulk properties and to modify friction logical applications either to reduce wear and/or methods for combating during contact. One of the foremost coating its widespread industrial wear is thermal spraying, however, despite behavior and the mecha- use, little is known about the basic friction Thus, most thermal spray wear nisms by which such coatings wear. based on empiricism. In coating applications and developments are life, Cr3C2-NiCr detonation order to prolong the conticaster roll’s in the steelmaking spray coating has been processed on the roll surface The wear behavior of the coating plant of Bao ShanSteel Company. The abrasive and dry fric- was studied systematically in this paper. Experi- tester. tional wear testing were performed on a pin-on-disk of the coated samples ment results show that the wear resistance those of the uncoated without the risk of seizure are much better than and sliding velocity. at room and elevated temperature with any load test condition were And the coating wear mechanisms under variation discussed. 4:15 PM of Properties of Corrosion-Resistant Development and Testing CVD Mullite Coatings for Silicon Nitride Boston, MA USA; Boston, MA Northboro, MA USA mond Film, progresses, it stainless steels technology of ion nitriding As the on the corro- effect of nitriding to examine the becomes imperative will give treated steel. This work of the surface of the sion resistance the nitriding of the conditions of into the relationship some insight resistance of the surface layer through treatment to the corrosion By varying the nitriding conditions, single their effect on its structure. layers can be obtained, leading to dramatic or multi-phase nitride resistance. As reported earlier, a textured changes in the corrosion phase (mphase) can be produced by nitriding tetragonal martensitic The corrosion resistance of m phase was com- under mild conditions. superior to that of a mixture of phases pared and found to be 3:35 PM 3:35 Stain- and 316L AISI 304 Nitrided of Ion Resistance Corrosion less Steels

WEDNESDAY PM 177 prospective, itis interesting toinvestigateeffectof aparticularsolute might beassociated withhighgrainboundarydiffusion. Fromthis high stressconditions.Itappears thattheroomtemperaturecreep sile strength.Nevertheless,itshows roomtemperaturecreepunder lent combinationoffulldensity, uniform grainsizeandultrahighten- Nanostructurednickelprocessed bypulseplatingexhibitsanexcel- P.O. Box9987,Baton Rouge,LA70813USA USA; versity, Dept.ofMech.Eng.,SixMetrotechCtr., Brooklyn,NY11201 M. Yin Creep BehaviorofCarbon DopedNanocrystallineNickel 3:15 PM microstructure againstgraingrowthatbothtemperatures. of 0.02wasinsufficienttoadequatelystabilizethesubmicron-size rate sensitivityindexof0.23.Themeasuredparticlevolumefraction achieved at350 a strain-ratesensitivityindexof0.35.Marginalsuperplasticitywas ticity wasachievedat510 boundaries asdeformationstrainincreased.Conventionalsuperplas- tion indicatedaprogressiveincreaseinmisorientationangleof the an adverseeffectonsuperplasticperformance.Microtextureevolu- superplasticity. Particlesizesgreaterthan0.56 at 530 strain of~13.8.Inclusionanintermediatesolution-heattreatment lowed bywarmworkingat200 tigated. Processinginvolvedhotworkingthematerialat300 ture strengthandsuperplasticperformanceat510 boundaries ranginginsizefrom0.3to0.50 channel angularextrusiontoasubmicronsizedmicrostructurewith CommercialgradeAl-5083wasprocessedinbulkformbyequal Mech. Eng.,800SwanPlace,Worland, WY82401USA Sinclair Processed byEqualChannelAngularExtrusion Microstructure andMechanicalPropertiesofAluminum5083 2:50 PMInvited properties. microstructures, theirthermalstability, andthesuperbsuperplastic posing apossibledeformationmechanismtoexplaintheobserved the specificityofthismetalworkingtechnique,andwearethenpro- tion occurringinECAprocessing.Inthispaper,wearefirstreviewing puzzling. Itappearstheyarecausedbythespecificmodeofdeforma- small grainsizeresultingfromtheprocess,otherresultsaremore some oftheobservedmechanicalpropertiescanbeexplainedby ties, particularlyatlowtemperaturesandhighstrainrates.Although submicrocrystalline (SMC)materialswithsuperbsuperplasticproper- technique hasallowedremarkableachievementsintheproductionof Inthelastfewyears,equal-channelangular(ECA)pressing Thousand Oaks,CA91360USA Patrick B.Berbon Deformation ModelDuringEqual-ChannelAngularPressing 2:25 PMInvited by hardparticles. sible forvacancynucleationandannihilationisconsideredtobepinned Ashby’s model,wheremotionofgrainboundarydislocationsrespon- nanoparticles. Thesestressesagreewiththosepredictedfromthe several tenMPa,dependingonthevolumefractionof which creepstops.Theestimatedthresholdstressrangesfromtento ably decayed,suggestingthepresence’s ofthethresholdstressesbelow sized. Inaddition,belowspecificstresses,thecreepratesareremark- grain boundarychemistrybydopingthenanoparticlesisalsoempha- remarkably improvedcreepresistance.Theimportanceofchangein interfaces causestheinhibitionofgrainboundarysliding,leading bonded tothematrixbyseveralapproaches.Therigidbondingof bition. Itwillbeshownthattheintergranularnanoparticlesarerigidly intergranular nanoparticlesandthematrix,itsroleincreepinhi- ics. Inthispapermuchattentionispaidtotheinterfacesbetween several ordersofmagnitudelowerthanthosethemonolithicceram- in creepresistance.Theratesofthenanocompositesareabout alumina orsiliconnitridematrixresultsinsignificantimprovements Thedispersionofnanometer-sizedsiliconcarbideparticlesinto ° 2 1 Southern UniversityandA&MCollege, Dept.ofMech.Eng., ; C followingaprocessingstrainof~9.2wasfoundtoenhance 1 ; S. H.Whang K. T. Hartwig ° C withelongationtofailureover250%andastrain- 1 ; 1 Rockwell ScienceCenter,1049CaminoDosRios, 1 ; R.Mirshams 1 ; R.E.Goforth ° C withelongationtofailureover400%and ° C and170 2 ; C.H.Xiao ° 1 ; C toacumulativeprocessing µ 1 m andtheroomtempera- Texas A&MUniversity, µ m werefoundtohave ° 2 ; C and350 1 Polytechnic Uni- : JohnW. ° C inves- ° C fol- : W. : ThemicrostructuresandmechanicalpropertiesofSi cho, Kita-ku,Nagoya462-8510Japan Research InstituteofNagoya,SuperplasticNanoscienceLab.,Hirate- R. Herling Alloy ProcessedbyEqualChannelAngularExtrusion Superplastic MicrostructureofModifiedAA-5083Aluminum 4:05 PM applied perpendicularlytothepressingdirection. as wellhighfracturetoughnesswereachievedwhenastresswas aries andwithintheSi with micrometer-sizeandnanometer-sizewerefoundatthegrainbound- tion. Inaddition,fortheSi Si rials exhibitedhighlyanisotropicmicrostructures,whererod-shaped Naoki Kondo Superplastically Sinter-ForgedSi 3:45 PM 3:35 PMBreak testing resultsandmicrostructurecharacterization. mechanisms atvariousconditionswillbediscussedbasedonmechanical microstructures ofthecreptspecimens.Effectcarbononcreep peratures. TheconventionalTEMhasbeenemployedtoinvestigate creep testswillbeperformedatlowloads50-100MPaandhighertem- to 800MPacomparedwiththatofpurenanocrystallinenickel.Further at roomtemperatureand373Kunderthestressrangingfrom200MPa line nickel.Thetensilecreeptestsshowedenhancedstrainrate temperature incontrastwiththesolutehardeningpolycrystal- carbon whilethetensileductilityandyieldstrengthdecreasedatroom that Young’s modulushasbeenimprovedsignificantlybyadding250ppm nickel dopedwith250ppmcarbon.Theexperimentalresultsshowed will reporttensilepropertiesandcreepbehaviorofnanostructured cant roleinthegrainboundarycharacteristics.Inthispresentation,we element onthecreepofthismaterial,inthatsoluteplaysasignifi- and controlexcessive graingrowthatSPFtemperatures. Mechanical addition ofZr,develop finedispersoidsthatassist ingrainrefinement SPF. Thesemodification,whichincludeanincreaseinMnlevel and the assist indevelopingafine,thermally stablemicrostructurerequiredfor fied 5000-seriesalloysidentified severalcompositionalfeaturesthat work performedatPacificNorthwest NationalLaboratoryonmodi- grain (~1micrometer),thermally stableSPFmicrostructure.Previous ECAE, a5000-seriesaluminumalloy inbulkformtoproduceafine- cessing ofSPFmaterials.Theobjectivethisworkwastoprocess, via mensions ofthestartingmaterial,asiscaseinconventionalpro- these desirablemicrostructuresinbulkform,withoutreducingthe di- grain size.Inaddition,withECAEthereistheuniqueabilitytoachieve role intherecrystallizationprocessandresultingthermallystablefine- ing theeutecticconstituentparticlesanddispersoidsthatplayacritical a welldefinedsubgrainstructureandprovidemechanismfordistribut- to achievehighlevelsofworkthroughlocalizedshearingcandevelop cessing ofSPF-gradealuminumalloys.TheabilitytheECAEprocess trusion (ECAE)processoffersseveralpotentialadvantagesinthepro- equiax microstructure~1micrometer. TheEqualChannelAngularEx- performance canbeachievedwiththedevelopmentofsmaller-grain cally limitedto5-10micrometergrainsize.AnimprovementinSPF mechanical-processing (TMP)schedules,themicrostructureistypi- to thingagesheet.Inaddition,throughconventionalrollingthermal- ing withverylargeingotsize,whilethefinalproductisusuallylimited cold worknecessarytoachievethedesiredmicrostructurerequiresstart- yield losses.Thesecondlimitationisthatthehighlevelsofhotand minum sheettypicallyresultsinsubstantialedgecrackingandoverall aluminum sheet.First,theextensivecoldrollingrequiredforSPFalu- ence onthecostandqualityofsuperplasticforming(SPF)-grades This approachhasdistinctlimitationsthatcanhaveasignificantinflu- and colddeformationsteps,usuallyintheformofhotrolling. superplastic microstructuresinaluminumalloysinvolveextensivehot Currentprocessingmethodsthatareusedtodevelopfine-grained 99352 USA Matls. Process.,902BattelleBlvd.,MailStop:P8-35,Richland,WA cron Si SiC, producedbyasuperplasticsinter-forgingtechniquefromsubmi- 3 N 4 grainstendedtobealignedperpendicularlytheforgingdirec- 3 N 4 orSi-Cpowders,wereinvestigated.Boththeobtainedmate- 1 ; MarkT. Smith 1 ; Yoshikazu Suzuki 3 N 4 grains,respectively. Very highbendingstrength 1 3 ; N 4 1 -SiC material, Pacific NorthwestNationalLaboratory, 1 ; Tatsuki Ohji 3 N 4 andSi β -silicon carbidegrains 1 ; 3 N 1 National Industrial 4 -SiC Ceramics 3 N 4 andSi : Darrell 3 N 4 - :

WEDNESDAY PM 178 University of Missouri, Dept. of Metallu. Eng., Missouri, Dept. of Metallu. University of 1 ; 1 Rajiv S. Mishra : 218 McNutt Hall, Rolla, MO 65409-0340 USA Hall, Rolla, MO 65409-0340 218 McNutt includ- of ultrafine grained materials, ten years synthesis In the last extending our up the possibility of has opened ing nanocrystalline, dependent phenomenon to a much finer mi- knowledge of grain size and creep deformation are known crostructural scale. Superplasticity the and the mechanistic understanding in to be grain size dependent is fairly good. The emerging experimental data microcrystalline range plasticity in the ultrafine grain size range on elevated temperature applicability of these mechanisms in this new allows us to evaluate the shows that the kinetics of grain bound- domain. The present analysis the processes are significantly slower than ary related deformation Some thoughts on the reason for these theoretical model predictions. discrepancies are presented. Break 4:45 PM Discussion tensile testing was conducted to evaluate the SPF properties of the properties the SPF to evaluate conducted testing was tensile materials. processed ECAE PM 4:25 Models for of Theoretical of the Applicability An Evaluation Grained Materi- Plasticity to Ultrafine Elevated Temperature als

WEDNESDAY PM 179

Daily Personal Schedule - Thursday - March 16 Opryland ConventionCenter 12:00 pm 11:30 am 11:00 am 10:30 am 10:00 am 12:30 pm 8:00 am 7:30 am 7:00 am 6:30 pm 6:00 pm 5:30 pm 5:00 pm 4:30 pm 2:30 pm 2:00 pm 1:30 pm 1:00 pm 9:30 am 8:30 am 9:00 am 4:00 pm 3:30 pm 3:00 pm Time Session

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Nashville, Tennessee, USA xiisMee Exhibits

❈ ting

March 12-16,2000 Other

THURSDAY AM 180 : ; 1 A. O. : ; J. E. Frei 1 ; M. B. Koss 1 University of Alabama, Dept. 1 ; 1 ; J. C. LaCombe 1 ; J. B. Andrews 1 Washington State University, Schl. of Mech. Eng., State University, Washington 1 ; 1 ; M. E. Glicksman 1 T. T. Phillips T. T. : Rennsselaer Polytechnic Institute, Dept. of Matls. Sci. and Eng., 110 Rennsselaer Polytechnic Institute, Dept. of Matls. of Matls. and Mech. Eng., DEC 254, 1150 10th Ave. S., Birmingham, 10th Ave. of Matls. and Mech. Eng., DEC 254, 1150 AL 35294 USA The intent of this study is to develop a theoretical model that will allow the prediction of the fluid flow patterns that form near the interface during directional solidification of hypermonotectic alloys. Convection driven fluid flows are anticipated in these alloys due to the low-density solute boundary layer that develops. This analysis is part of a larger project to determine how fluid flow in the liquid adjacent to the interface can affect the stability of the solidification front. Ex- perimental verification of the model will be obtained by directionally solidifying samples of the transparent metal analogue system, succinonitrile-glycerol, in a temperature gradient stage microscope. Experimental observation of fluid flow in the liquid phase near the interface will be facilitated by the use of tracer particles. 9:50 AM Break 10:10 AM Magnetically Driven Flows in Levitated Droplets Turbulent Suping Song 99164 USA Pullman, WA This paper presents a numerical presentation of turbulent flow phenomena in magnetically levitated droplets. A finite element model with a variety of engineering turbulence models has been developed and applied to study the turbulence phenomena in TEMPUS systems. With the developed model, the turbulence in a magnetically levitated solidification models. In these studying: both theoretical and applied both theoretical models. In these studying: solidification plays an of numerical algorithm pursued. The selection objects are provide To of crystal growth. in computer simulation important role should appro- numerical algorithm at a reasonable cost reliable results that is or technological process specific physical case priate to the used: the first one formulation could be kinds of Two considered. equations for each phase and am- utilized independent conservation boundary conditions at the phase interface. poule with appropriate as multiple domain solutions. The second Such methods are referred formulation in all physical domains which one consists in continuum separating the phase conservation equations. eliminates the need of approach associated to homogeneous for- Finite volume monodomain the thermodiffusion Stefan model corre- mulation is used for studying so- solutions. The approach describes the sponding to experimental the with unsteady melt interacting with lidification of a pure material with phase transition temperature depend- interface and binary alloy of the liquid phase. ing on the composition 9:10 AM Growth Data Reduction of Microgravity Dendritic Lupulescu 1 NY 12180-3522 USA Rm. 4219, Troy, 8th St., C11 on dendritic growth in The IDGE consisted of 180 experiments Sev- experiments on pivalic acid (PVA). succinonitrile (SCN) and 116 space flight con- eral discoveries were made during each microgravity IDGE film and telem- cerning the behavior of these model dendrites. radii versus supercooling etry data provide benchmark tip velocity and and the interfacial for critically testing dendritic transport theory these reduce To growth of PVA. physics of diffusion-limited processing system com- microgravity data, we developed an image software and custom prised of a monochrome camera, Image-Pro and implement the macros. The macros provide digital tomography for varying re- required shape regressions as a series of polynomials The resultant radii are gions of the interface near the dendrite tip. the sampling region. The currently being examined as a function of will be added to the data base for SCN tip shapes, tip shape data PVA phase-field predic- allowing quantitative testing of three-dimensional tions. 9:30 AM Near the Solidifi- Theoretical Analysis of Fluid Flow Patterns Directional Solidifi- cation Front in Hypermonotectics during cation is η A. V. is the p : THURSDAY AM THURSDAY The University of 2 is the drag force, d Universite d’Aix Marseille, 1 NASA Marshall Space Flight 1 where F . This is compared to the theo- ; 3 0.577), and d is the width of the γ 3/2 1 ; is the particle velocity, R is the particle velocity, 1 10 p γ≅ /d) p /d) p (R p (R p V ; S. Sen V 2 Πη Robert Schiffman, R. S. Research, Robert Schiffman, R. 2 Πη will be discussed. It will be shown that the d √ Location: Opryland Convention Center Location: Opryland 3 √ M. El Ganaoui = = 3 : num d Mike B. Robinson, MSFC/NASA, Science ASM International: Materials Science ASM International: theor d is Euler’s constant ( is Euler’s γ ; D. M. Stefanescu 1 the dynamic viscosity of the fluid, V IRPHE-UMR, 6594 CNRS, IMT 38 Joliot Curie, Marseille 13451 France The numerical modeling in the growth of semiconductor crystals and metal alloys plays an important role in the development of the understanding of the interplay between transport processes such as convection and diffusion. The problems arising: in full-scale computer simulation of crystal growth have stimulated the designing of new efficient and accurate numerical methods for solution of the comples classical theory to calculate the drag force on a particle can be used only within certain limits. The proposed numerical model was validated against the classical theory within these limits and the microgravity experimental results. 8:50 AM Numerical Study of Directional Solidification under Micro- gravity Conditions retical solution: F Session Chair: Directorate 47, Huntsville, AL 35812 USA 8:30 AM Acting on an Insoluble Numerical Calculation of the Drag Force Interface of a Solidifying Particle Moving in Front USA; Center, USRA/SD 47, Huntsville, AL 35182 Alabama, Tuscaloosa, AL 35487 USA a metal casting depends The distribution of insoluble particles in the solid/liquid inter- primarily on the interaction of the particles with Microgravity experiments face (SLI) during the solidification process. missions to study have been performed on board the LMS and USMP-4 a particle will be en- the fundamentals of this interaction. Whether by the balance of the gulfed or pushed by SLI is essentially determined component of this force forces acting on the particle. An important motion in front of balance is the drag force generated by the particle models for particle/SLI the SLI. Previously developed mathematical of this force provided interaction made use of steady-state solutions on the our numerical model based However, by the lubrication theory. the steady-state approach SLI tracking approach shows that not only but also that even at is inappropriate to model the interaction process, the drag force. It steady-state the theoretical solution underestimates was found that regression analysis of steady-state numerical solutions for cylindrical particles moving normal to a flat SLI gives a relationship of the form F particle radius, gap between the particle and the SLI. The influence of the interface shape on the value of F Thursday AMMarch 16, 2000 Room: Memphis A Inc., Barton, VT 05822 USA; Carlo Patuelli, Universita di Inc., Barton, VT 05822 di Fisica, Bologna I-40126 Italy Bologna, Departimento Critical Technology Sector, Electronic, Magnetic & Photonic Electronic, Magnetic Sector, Critical Technology Structural Materials Division, Alloy Materials Division, Thermodynamics & Phase Equilibria Phases Committee, Committee Program Organizers: Sponsored by: 12th International Symposium on Symposium 12th International for Microgravity Methods Experimental Session 5 Science: Materials Catalina

THURSDAY AM 181 35812 USA; of AlabamainHuntsville,SD47,MarshallSpaceFlightCenter,AL acceleration can approach1gforevenasmall rotation rate.Prior microgravity containerless processingsystems,where thecentrifugal tion isanimportantissue.Sample rotationisevenmoreimportantfor Inmanycontainerlessprocessing systems,controlofsamplerota- nology, Pasadena, CAUSA Space FlightCenter, Huntsville,ALUSA; Hyers Reduction ofSampleRotation in Electrostatic Levitation 11:10 AM themes intheNASAresearchprogram. tives witheachMSRRsupportingawiderangeofmaterialsscience near-term andlong-rangematerialssciencedisciplinegoalsobjec- apparatus. TheMSRFwillbetheprimaryapparatusforsatisfying investigation uniqueapparatus,and/ormulti-usergenericprocessing prised ofon-orbitreplaceableExperimentModules,ModuleInserts, System (ARIS).EachMSRRisanautonomousrackandwillbecom- operating eachdevice,andwillusetheISSActiveRackIsolation materials processingapparatusandcommonsubsystemsrequired for ning onthethirdUtilizationFlight(UF-3).Thefacilitywillhouse the phased deploymentintotheUnitedStatesLaboratoryModulebegin- Racks (MSRR-1,MSRR-2,andMSRR-3)whichwillbedevelopedfor (ISS). TheMSRFconceptconsistsofthreeMaterialsScienceResearch in themicrogravityenvironmentofInternationalSpaceStation reviewed materialsscienceinvestigationsselectedtoconductresearch ity designedtoaccommodatethecurrentandevolvingcadreofpeer- TheMaterialsScienceResearchFacility(MSRF)isamodularfacil- 35812 USA tional AeronauticsandSpaceAdministration,SD44,Huntsville,AL David AllanSchaefer Experiment ApparatusfortheInternationalSpaceStation Development oftheMaterialsScienceResearchFacilityand 10:50 AM activities andselectedresults. also presentscurrentprototypeQMIhardwareanalysisandtesting design featuresandperformancecapabilitiesofeachinsert.Thepaper on FickianandSoretdiffusioninliquids.Thispaperdiscussesspecific DMI isavacuumBridgman-Stockbarger-typefurnaceforexperiments used forexperimentsondirectionalsolidificationofmetalalloys.The high-gradient Bridgman-typevacuumfurnacewithquenchcapabilities Insert (QMI)andtheDiffusionModule(DMI).TheQMIisa installed onorbit.NASA’s plannedinsertsincludetheQuenchModule different removableandreplaceableModuleInserts(MIs)whichare Space Agency(ESA).ThisNASA/ESAEMwillaccommodateseveral (EM) beingdevelopedcollaborativelybyNASAandtheEuropean Science ResearchFacility(MSRF)containsanExperimentModule TheMaterialScienceResearchRack1(MSRR-1)ofthe Huntsville, AL35806USA Flight Center, AL35812USA; Center, AL36812USA; Space FlightCtr., ThermalDesignGrp.,ED25,MarshallSpaceFlight Flight Ctr., MarshallSpaceFlightCenter, AL35812USA; nautics andSpaceAdminstration,SD42,GeorgeC.Marshall Carswell the InternationalSpaceStation (MSRR-1) oftheMaterialScienceResearchFacility(MSRF)on Insert ConceptsfortheMaterialScienceResearchRack1 10:30 AM conditions. being carriedtofurtherassessthedropletoscillationunderturbulence suming aneffective constantmolecularviscosity. Furtherstudiesare tion withinthedropletmaybeapproximatedreasonablywellbyas- and themagnitudeofvelocitiesalsotemperaturedistribu- with thesemodels.Theresultsfurthershowthatthefluidflowpattern able topredictthefluidflowlevelwithaccuracyrangeassociated predictions differforstandardtestproblems,thesemodelsseemtobe model, andthek-eRenormalizationgroupmodel.Whilemodel Reynolds numberturbulenceflowmodels,standardk-emodel,k-w droplet hasbeenstudied.Theappliedturbulencemodelsincludelow 1 ; W. L.Johnson 2 ; JeffFarmer 3 National AeronauticsandSpaceAdministration,Marshall 1 ; SharonDeniseCobb 3 ; FredRose 2 ; L.Savage 4 Pace andWaite, Inc.,SD42,MarshallSpace 5 Micro Craft,Inc.,620DiscoveryDr., 4 : ; PaulH.Tidwell 1 ; J.R.Rogers Myscha R.Crouch 2 California InstituteofTech- 1 ; FrankR.Szofran 1 ; 5 ; 1 NASA Marshall 1 National Aero- 1 ; WilliamE. 2 University : 1 ; R. W. 1 Na- : Gladstone, Queensland4680Australia Session Chair: March 16,2000 Thursday AM Limited, Gladstone,Queensland4680Australia Pittsburgh, PA 15219USA;JoeAnjier, QueenslandAlumina Program Organizers: Sponsored by: Trends, Products, Environment Alumina andBauxite:Industry torque duetophotonpressureispresented. compared totheoreticalpredictions,andastrategyforminimizingthe results showingthecorrelationbetweenheatingpowerandtorqueare MSFC ESLisphotonpressurefromtheheatinglaser. Experimental dominant drivingforceforrotationofmachinedZrspheresinthe forces forundesiredsamplerotation.Ourexperimentsshowthatthe simplest approachistoidentifyandbalanceoreliminatethedriving we havetakenthefirstapproach.To minimizesamplerotation,the control loopinparallelwiththepositionloop.Inthiswork, ired samplerotation,orsecond,implementafeedback-basedrotation first, toidentifyandbalanceoreliminatethedrivingforcesforundes- rotation. To minimize samplerotation,twoapproachesareapparent: fast rotation,butformanymicrogravityexperimentsthegoaliszero measurement ofelectricalconductivity. Histechniqueallowscontrolled, rotation atacontrolledratefordropletdynamicsexperimentsand work onrotationcontrolbyRhim[1]focuseddrivingthesample plants andpotential newprojectsarereviewedin the lightofforecast the accuracyof forecasted marketbalance.Prospects forexisting show anerrorof20%.Errorlong-term priceforecastdependson tion whileformedium-termforecasts (onemonthtoonequarter) to oneweek)theerrorisaround30% ofcasesforecastedpricesdirec- the pricemodelhasbeenevaluated. Forshort-termforecasts(2days cially intheactivityofmajormarket participants.Theaccuracyof term, however,speculativefactors playasignificantrole,seenespe- a goodbasisfordevelopinglonger-termpriceforecasts.Intheshort warehouses andbyproducersconsumers,pricetrendsprovide between supplyanddemand,stocklevelsheldbothinterminalmarket ematical functions.Itisclearthatmarketfundamentals,thebalance of marketparticipants,producers,consumersandtraders,tomath- fore, amodelhasbeendevelopedwhichreducestheaimsandbehaviour and thenumerousempiricalcoefficientsthatmustbeutilised.There- the lackoftimelyandaccuratedataforsomenecessaryinputs analysing thesemarketparametersdonotgivegoodresultsinview of However, forecastingmodelsbasedontheusualstatisticalmethods for short andmedium-termpriceforecastsforaluminiumalumina. volumes andfundamentalmarketbalancesissufficienttodevelop rent marketpricetrendsanddynamics,metalstockmovements,traded aluminium pricesusingmarketinputs.Ananalysisofrecentandcur- t. Thereisadiscussionofforecastingmethodologyforaluminaand and $130/twhilesmeltingcostswerecuttobetween$800$1100/ direct cashcostsofaluminaproductioninRussiafelltobetween$90 economic crisis.Asaresultofthefour-folddevaluationinrouble for allRussianrefineriesandsmeltersbeforeafterAugust1998’s analysis ofthedirectcashcostsaluminaandaluminiumproduction and aluminiumexportstotheWest of2.5Mt/a.Thispaperprovidesan tries inRussia,throughimportsof2Mt/aWestern aluminaintoRussia kets aretodaycloselylinkedtodevelopmentsaffectingtheseindus- ThefortunesoftheWestern World’s aluminaandaluminiummar- burg Russia and Prospects Russia’s AluminumIndustryAfterAugust1998Crisis:Status 8:30 AM : Boris I.Arlyuk Light MetalsDivision,AluminumCommittee Joe Anjier, Queensland Alumina Limited, Location: OprylandConventionCenter Room: JeffersonB Vito Cedro,AlcoaWorld Alumina, 1 ; 1 Alumconsult Limited,St.Peters-

THURSDAY AM 182 ; Sigfried 1 VAW Alu- VAW 2 Pierre Reny Pierre : Regional Research Labora- 1 ; 1 John Chen, University of Auckland, Room: Sewanee Location: Opryland Convention Center B. K. Mohapatra : Pierre Homsi, Aluminum Pechiney, Saint- Pierre Homsi, Aluminum Pechiney, Light Metals Division, Aluminum Committee Aluminerie Alouette, Inc., 400 Chemin de la Pointe- 1 ; 2 8:30 AM Invited Study at Alouette Graphite Cathode Wear Wilkening Sept-Iles, Quebec G4R5M9 Canada; Box 1650, Noire, P.O. Germany Box 2468, Bonn 53014 GmbH, P.O. minium-Technologie Between 1996 and 1999, graphitized cathodes were installed in the 264 AP- 30 pots at Aluminerie Alouette, Inc. aluminium smelter. During this period, an extensive cathode erosion study was undertaken with the primary objective of predicting potlife. A method to accu- Aluminum Reduction Technology: Cell Aluminum Reduction Technology: Operation/Electrodes Sponsored by: Program Organizers: Department of Chemical & Materials Engineering, Auckland, New Zealand; Georges J. Kipouros, Dalhousie Department of Mining and Metallurgical University, Engineering, Halifax, NS B3J2X4 Canada Thursday AM March 16, 2000 Session Chair: Jean-de-Maurienne 73303 France Red mud, a colosal solid waster from bauxite processing, was treated was bauxite processing, from solid waster mud, a colosal Red by am- and re-precipitation acid in hydrochloric dissolution by simple used to was This material mud (ARM). red to form activated monia like paramenters Various solution. from aqueous nickel (II) remove were deter- mud to metal ion ratio, time, temperature, red pH, contact for an of nickel (II) was achieved than 60% removal mined. More increases by Removal of metal ion of 10 ppm. initial concentration due to precipi- but thereafter drops the medium up to 6.5 raising pH of was ob- in rate of absorption hydroxides. Increase tation of metal of ARM in- The loading capacity rise in temperature. served with (II) removal at 10 ppm initial concentration creased with higher Ni concentration of 20g/L. The experimental was observed for an ARM Freundlich and Langmuir adsorption isotherms. data agreed well with extended to removal of heavy toxic metal Adsorption studies were effluents of electroplating and chromite ions from aqueous industrial mining industries. AM 11:20 Mud Generated at NALCO Refinery, Characteristics of Red Damanjodi, India Bhubaneswar 751013 India tory, at the NALCO Alumina Refinery in Damanjodi, Red mud generated with respect to particle size, settling India, has been characterized and the reason for loss of mineral chemistry, properties, mineralogy, Red mud com- some alumina value in the rejects has been establishes. poor in settling, and prising fine solid particles (average 5) is alkaline, constituents are he- has 13-16m2/g specific surface area. Its mineral grains, specks of matite, gibbsite, geothite, boehmite, rutile/ilmenite minor sodalite. Elec- lithoretics like kaolinite, sillimanite, etc., and the presence of up tron probe analysis on selective particles indicated crystals and up to to 64-mole% of boehmite coexisting with gibbsite generated at different 18% of alumina in goethite. Red mud samples such as Digested Mud (DM), Deslicated Mud stages of the refinery, and Mud to Pond Mud (WM), (DSM), Stlleter Mud (SM), Washer and mineralogical (MTP) are more or less similar in their physical differences in their properties, but exhibit minor but distinguishable some phases like chemical characteristics. In the alumina refinery, Al-rich lithorelics, dehydroxylated gibbsite, boehmite, alumo-goethite, of bauxite and get etc., do not dissolve during the industrial treatment reduce the recovery of released as constituents of red mud and thereby alumina significantly. : C C C, ° ° ° C. ° Patrick R. : Showa Denko 1 ; 1 Regional Research 1 C, the MOI to 300 ; ° 1 Eiji Kanbara University of Oviedo, Dept. of 1 ; 1 ; 1 Zhengzhou Light Metals Research 1 ; R. S. Thakur 1 C-MOI-and the LOI to 1200 ; ° 1 C, according to the standard tests, and the alu- ° Miguel Llavona ; S. N. Das 1 : ; Susumu Shibusawa 1 Qingwei Wang : Alcoa, 201 Isabella St., Pittsburgh, PA 15212 USA PA Isabella St., Pittsburgh, Alcoa, 201 1 J. Pradhan ; 1 : Laboratory, Bhubaneswar 751013 India Laboratory, Akira Sakamoto Institute, Shangjie District, ZhengZhou, Henan 450041 PRC Institute, Shangjie District, ZhengZhou, Henan powder was modified The surface of common aluminum hydroxide resisting group was by multilayer wrappings. The cooperating flame of the aluminum grafted into the surface active agent. The affinity and the thermal stability hydroxide for polymner, the flame resistance Thus it can have application widely in plastics are improved markedly. and rubber with high temperature processing. 10:10 AM Break 10:30 AM Improvement in Reactivity of Bayer Process Alumina Powders the content in hydrate to 500 Yokohama, 8 Ebisu-cho, Kanagawa-ku, Works, K.K., Yokohama Kanagawa 221 Japan Due to its excellent properties (resistance to heat/corrosion/abrasion, electrical insulation and thermal conductivity), alumina has been used as material for such sintered bodies as IC substrates, cutting tools and abrasion-resistant parts. Alumina for such applications should have small alpha-ultimate crystal size and be sinterable at low temperatures, and should result in sintered bodies with excellent mechanical strength, hardness and abrasion resistance. So far, thermal decomposition of high-purity aluminum salt has been a general way of producing ultra fine alpha-alumina particles, which method involves a disadvantage of high production cost. Established, through application and develop- is a method of ment of Bayer reactive alumina powder technology, producing alpha-alumina with fine particle size and purity of four nines. 10:55 AM Removal of Nickel from Aqueous Solution Using Activated Red Mud Matls. Sci., Reinero Garcia s/n, Mieres 33600 Spain Matls. Sci., Reinero Garcia s/n, Mieres 33600 is produced due to the In industrial aluminas, certain segmentation the particles. The fine difference in the size, form and density of alumina and their particles contain more residual hydrate, alpha If the the specific area is smaller. microporosity is higher; however, moisture of the aluminas is determines to 110 and the LOI to 1200 and LOI will be seen mina contains hydrate, the values of the MOI loss of weight to 500 altered and they will not have meaning. The the industrial aluminas. has been related with the content in hydrate in the aluminas to 110 It is important to determine the moisture of 9:45 AM Stability and Flame Aluminum Hydroxide with High Thermal Resistance The International Primary Aluminium Institute (IPAI) conducted a Institute (IPAI) Primary Aluminium The International technologies, information on the survey in 1991 to gather worldwide industry to used throughout the practices and resources monitoring The survey also gathered data on the rate rehabilitate bauxite mines. activities. Responses were received and timing of the rehabilitation “Baux- producers by tonnage. A report, world’s from over 65% of the published in 1992. A second was Survey,” ite Mine Rehabilitation completed and data will be used to develop worldwide survey has been status of bauxite mine rehabilitation report on the an updated IPAI The 1998 survey contains responses from over throughout the world. tonnage. This paper will compare producers by 70% of the world’s mine reclamation survey with the information results from the first areas of significant progress and areas received in 1998 to highlight can provide assistance to the bauxite indus- where technology transfer mining enterprises. try and perhaps other 9:20 AM of Metallurgical A Study of the Effect of Hydrate on Properties Grade Aluminas world market prices for alumina and aluminium. This forms the back- forms the This and aluminium. for alumina market prices world require- import alumina for Russian outlook to a near-term ground West. to the for export metal of aluminium and availability ments 8:55 AM World the Reclamation Throughout Bauxite Mine Atkins

THURSDAY AM 183 total heatisdissipated throughthecathodebottom. Theamountof portant roleinthe potdesigneventhoughonlyasmall amountofthe Cathodeinsulation inaluminiumelectrolysiscells playsaveryim- mark A/S, Rsrch.andDev., Ostergade 60,Nykobing,MorsDK-7900 Den- Materials Thermal ConductivityMeasurements ofCathodeInsulation 10:25 AM 10:15 AMBreak oxidizing andreducingatmospheres. mineralogical componentsoftherefractorymaterials,whentested in were discussed,particularlyemphasizingthereactivityofdifferent and therefractories’microstructure.Themechanismsofcorrosion correlated withthetestingparameters,cryoliticbathchemistry and drygranularmaterials.Thepenetrationcorrosionresultswere permeability, wereconsidered andstudiedonvariousbricks,castables cryolite penetration,twomainparameters,openporosityandgas Inordertoassessthebehaviorofadensebarrierrefractorytowards Canada Matls. Eng.,309-6350StoresRd.,Vancouver, BritishColumbiaV6T1Z4 V2S5CI Canada; Refractories Limited,33765PineSt.,Abbotsford,BritishColumbia minium ElectrolyticCells Cryolite PenetrationStudiesonBarrierRefractoriesforAlu- 9:50 AM relining scheduling. residual lifetimeforagivencellmaysupportdecisionsonstrategic effect ofeachrestartonthecelllifeaverage.Calculationmean in operation.Thisanalysisindicatedclearlythenegativeandadditive precise situationwheremanycellsfromtheplantpopulationarestill starts andcelllife.Thismethodappearstobeverywelladaptedthis product estimatetoevaluatetherelationbetweennumberofre- using aspecialstatisticalmethodbasedontheconceptofriskandlimit potlinning life.Manyplantdatafromvarioussmelterswereanalyzed economic conditionsoremergencysituationsdoaffectnegatively Itisaknownfactthatprematureshutdownsandrestartsbecauseof Box 1250,JonquièreG7S4K8Canada International Limited,ReductionTech. Svc.,1955MellonBlvd.,P.O. Effect ofMultipleRestartsonCellLife 9:25 AM consideration. particular celltechnologyandstart-upconditionsmustbetakeninto until reachingcelloperatingtemperature.Whenselectingapastethe only lateintheheat-upcycleandstaydimensionallystableafterwards a smoothexpansionuntilbindercarbonisationwhichshouldtakeplace blocks, andcorrelatedtosmelterresults:aproperpasteshouldexhibit changes inacellduringstart-up,withspecialfocusongluedcathode temperatures. Theresultsarediscussedwithrespecttothespecific ing heat-up,alkaliresistance,andmechanicalstrengthatelevated green andbakedproperties,expansion/shrinkagecharacteristicsdur- able rammingpasteshavebeenlab-testedforbehaviour, performance ofaluminumelectrolysiscells.Fourcommerciallyavail- Theimportanceoframmingpasteisoftenunderestimatedforthe nology &ManagementLimited,CH-3965Switzerland Plant, Stroofstrasse27,FrankfurtD-65933Germany; Hiltmann Ramming PastePropertiesandCellPerformance 9:00 AM of areaswherespallingthecathodeoccurredatstart-up. accuracy ofthisanalysismethodissuchthatitenablesidentification age, orpotlineamperageevolutionaswasthecaseatAlouette.The odes alsoshowthattheerosionspeeddoesnotappeartovarywithpot with electricalmodels.Fixedintervalmeasurementsofselectedcath- suggests acurrentdensity-drivenphenomenon,whichisinagreement not theleadingerosionmechanism.Thelargescalepattern that mechanicalerosion,atthetappingholeorelsewhereinpot,is still ongoingbuttheanalysisofpreliminaryresultsshowevidence the paperalongwithmeasurementsaccuracyestimates.Thestudyis This methodusesasurveyor’s laserlevelequipmentandisdetailedin rately measurecathodeerosiononanoperatingpotwasdeveloped. 1 ; KarlHeinzMeulemann : Flemming BayAndersen 2 University ofBritishColumbia,Dept.Metals& : Don Harris 2 ; 1 1 SGL CarbonGmbH,Griesheim ; JørgenMikkelsen 1 ; GeorgeOprea : Paul Desclaux 2 Alusuisse Tech- 2 ; 1 ; : 1 1 ; Clayburn 1 Skamol 1 Frank Alcan Oyama Homma Anode ImprovementsatAlcanBrazil’sHSSPotlines 10:50 AM examined anddiscussed. dence ondensity, temperatureandanisotropyofthemicrostructureis ing firebricksofaluminosilicate.Thethermalconductivitydepen- miculite slabs,diatomacousearthandperlitebricksfinallyinsulat- insulation materialwithdifferentproperties:Calciumsilicateandver- been usedtomeasurethethermalconductivityofseveralkinds materials havebeenexamined.Theso-calledHotDiskMethodhas mal conductivityisthekeypropertyofinsulationandarange choice ofinsulationcanhavealargeinfluenceonpotlife.Thether- insulation determinesthetemperaturegradientsincathodeand viewed. mina-bonded titaniumdiborideslurry. Techniques andresultsarere- spray, titaniumdiboridecarbon/graphite compositesandcolloidalalu- nium diboridecoatingwithreinforcedfibres,titaniumplasma tory andplanttestsincludetitaniumdiborideelectrodeposition,tita- cathodes hasadvancedconsiderably. Coatingmethodstriedinlabora- Duringthelastfewyears,developmentofaluminiumwettable Avenue duRothorn14,SierreCH-3960Switzerland 1 Aliminium Wettable Cathodes:AnUpdate 11:40 AM sacrificing serviceperformance. lining byusinglargesizeSi3N4-bondedSiCbricksaspossiblewithout tion isprovidedbasedonexperimentalresultstodesignaside-wall of thesizeandweightwithmechanicalproperties.Helpfulinforma- adjusting processingparameters,andoninvestigatingtherelationship fabricating Si3N4-bondedSiCbrickswithdifferentsizesandweightsby bonded SiCbrick.Therefore,inthisthepaper,attentionisfocusedon is oneoftheeffectiveapproachesbyincreasingsizeSi3N4- service performanceofside-walllining,reducingthenumberseams corrosion resistancethanthatofSi3N4-bondedSiCbrick.Inorderto Theseamofside-walllininginaluminumelectrolysiscellhaslower 43 XiyuanRd.,Luoyang,Henan471039China Guohua Liu Electrolysis Cell The PropertiesofSi 11:15 AM discussed. paste consumption.Theimprovementsoncelloperationsarealso Brazil’s HSSpotlines,whichledtoareduction ofaround50kg/mtin the pasteandanodeoperationoverlast20years,atAlcan procedures. Thispaperdescribesalltheimprovementsimplementedin performance isalsorelatedtothecell(anodeandcathode)operational formulation andpasteproductionprocess.Besidesthat,theanode it isusuallyafunctionofrawmaterialsquality(pitchandcoke),paste paste consumption,buttheoverallcelloperationalperformance,and elements fortheseimprovements.Theanodequalityaffectsnotonly tion factors,andtheanodequalityitsoperationarebasic improvement. Theanodeplaysanimportantroleintheseconsump- been madeaimingatpowerandrawmaterialsconsumptionfactors many othersmelters,severaleffortsandprocessdevelopmentshave Duringthelast20yearsatAlcanBrazil’s HSSpotlines,asin Minas Gerais,Brazil Am’erico ReneGianetti521,35.400-000-Saramenha,OuroPreto, Technical InformationServicesandConsulting,LeForumdesAlpes, 1 ; Z.Cheng 1 ; : 1 Alcan AluminiodoBrasilLtda,ReductionArea,Av. Junguo Zhao 3 1 N ; 4 1 -Bonded SiCMaterialforAluminium Luoyang InstituteofRefractoryResearch, 1 ; ZhipingZhang : Rudolf P. Pawlek 1 ; Wenwu Wang : Rui 1 1 ; ;

THURSDAY AM 184 ; Trond 1 ; Lindsay 2 Japan Sci- 1 ; 2 ; Alice Bunn 1 Eivind Bondhus ; Kenji Miwa 1 : ; Pavel Cizek 1 Alireza Radjai : University of Cambridge, Dept. of Matls. Sci. and of Cambridge, Dept. University 2 Peter Schumacher National Industrial Research Institute of Nagoya, Materi- 2 Hydelko KS, Saheimsveien, Rjukan 3660 Norway : 1 University of Oxford, Dept. of Matls., Parks Rd., Oxford of Oxford, Dept. of Matls., University 1 ; 1 ; 2 ence and Technology Corporation, National Industrial Rsch. Insti. of ence and Technology Nagoya, Matls. Processing Dept., 1-1 Hirate-cho Kita-ku, Nagoya 462 Japan; Hydelko presents a new combination alloy for use in hypoeuctectic Hydelko presents a new combination alloy addition today’s aluminium silicon foundry alloys. Strobloy simplifies the number of addi- practice of grain refiner and modifier by reducing product between the tions from two to one. Strobloy is a combination and strontium. The alloy contains nucleating well-established TiBloy, Ti)B2, which is benefi- particles in the form of the mixed boride (Al, Strontium is present cial regarding settling and grain refining efficiency. out indicate that Strobloy as fast-dissolving Al4Sr particles. Trials carried additions of TiBloy/ shows very good performance compared to separate and The grain refining efficiency and AlSr master alloy. AlTi5B1 This paper displays results modification level is the same or better. levels in an A356 collected from tests done with different strontium and AlSr are pre- Comparisons to separate additions of TiBloy alloy. sented. 10:25 AM Structural Refinement of Hypoeutectic Al-Si Alloys by Elec- tromagnetic Vibrations als Processing Dept., 1-1 Hirate-Cho, Kita-ku, Nagoya 462 Japan Simultaneous imposition of alternating electric and stationary magnetic fields on a conducting liquid will induce a vibrating motion in the liquid which can lead into the formation and collapse of cavities in the liquid and affect the solidification structure. This phenomenon and the effects of the two main parameters of frequency and intensity of Based on a super- vibrations have been studied in an Al-7% Si alloy. conducting magnet, an experimental apparatus that enables the simultaneous application of an alternating electric field with a frequency of up to 50 kHz and a magnetic field of up to 10 T has been designed and assembled. The thorough investigation, which has been carried out over wide ranges of intensity (an electromagnetic pressure range of (0 to 2.25 X 10⁵ Pa) and frequency (0 to 50 kHz), clarified the effects of the two main parameters on the structural refinement brought about by electromagnetic vibrations. Microscopic observations have shown that the cavitation phenomenon, being a main factor behind the structural refinement, has been effective over a specific Greer OX13PH UK; Cambridge CB23QZ UK Metallu., Pembroke St., containing TiB2 and Al3Ti particles were Grain refiner additions Al-Ni-Zr melts which upon rapid cooling form successfully added to region of the undercooled melt nucleation glasses. In the temperature the and subsequent growth of Al was halted at of aluminium occurred resulting in nucleation and growth centres glass transition temperature in matrix. Similar to earlier observations, separated by an amorphous a layer of the type Al3Ti adsorbed on basal which no Zr was present, particles acted as a potent nucleation sub- faces of hexagonal TiB2 found to be a thermally activated process ob- strate. Poisoning was firstly adsorbed Zr affected exposure to Zr. served on prolonged be borides. The adsorbed layer of Al3Ti can aluminide layers and then a lower peritectic temperature than Al3Ti replaced by Al3Zr having At higher processing temperatures it was and hence lower potency. the delicate epitaxial found that TiB2 transformed to ZrB2 affecting believed to enhance the relationship between boride, aluminide and Al findings are discussed potency of the aluminide-covered borides. The casting prac- and found to be consistent with respect to conventional tice. 9:50 AM Break 10:00 AM and Modifier for Strobloy–The New Combined Grain Refiner Hypoeutectic AlSi Foundary Alloys melt and cannot act as stabilised Al3Ti layer on borides. However, a However, layer on borides. Al3Ti act as stabilised cannot melt and indi- of the boride faces at non-based epitaxial is nucleated new phase for suc- factor an important matching is that crystallographic cating nucleation. cessful 9:25 AM Melts Con- Rod Additions in Al of Ti-B-Al Refiner Poisoning taining Zr Sagstad : . It is of -2 University 1 ; 1 ; Keyna Q.A. 1 to 10 -3 in the case of present 2 ; Pavel Cizek 1 ; A. Lindsay Greer 1 Paul Crepeau, General Motors Paul Crepeau, Location: Opryland Convention Center Location: Opryland ; Brian J. McKay Arnaud Tronche 1 Barbara L. Kidwell, Alcoa Warrick Opera- Alcoa Warrick Barbara L. Kidwell, Light Metals Division, Aluminum Committee Division, Aluminum Light Metals : University of Oxford, Dept. of Matls., Parks Rd., Oxford 1 ; 1 OX13PH UK Grain refiner additions in Al-Si in conventional casting practice require higher amounts of excess Ti than in wrought aluminum alloys, however, beyond 3 wt.% Si the grain refiner efficiency is greatly reduced. The effects of Si on the nucleation mechanism of TiBAl (Al- 5wt.% Ti-1wt.%B) are unknown. A novel metallic glass technique permits the addition of refiner particles into a melt of Al70Ni13Si17 (at.%) which higher solute content facilitate glass formation on rapid cooling. Nucleation of Al occurs in the undercooled melt while growth is effectively halted at the glass transition temperature resulting in discrete nucleation and growth centres suitable for TEM investigations. Three types of nucleation centres have been identified in the as quenched structure: hexagonal TiB2 platelets, dendritic aluminides and hexagonal devitrification products. Interestingly at high Si levels the borides appear not to be covered in Al3Ti as in previous studies without Si addition and do not nucleate Al on basal faces while the dendritic and devitrification phase nucleate heterogeneously copious Al crystals. This suggests that the excess-Ti has been consumed within the interest to explore the reasons for such low values, and to assess the interest to explore the reasons for such low of refiners. Recently prospects for increased efficiency though design model can make it has been shown [1] that a simple recalescence-based of refiner addition quantitative predictions of grain size as a function model, the initiation of level, cooling rate and solute content. In the particles, the size grains is limited by the free growth from nucleant present work uses this distribution of which is very important. The particle size distribution model as the basis for discussing the effects of on refiner performance. Larger particles (of TiB as do narrower size distributions. interest) promote greater efficiency, be exactly specified, It is shown that even if the size distribution could efficiency (defined as compromises would have to be made to balance [1] A.M. Bunn, P.V. above) with the required addition level of refiner. Metals 1998’, edited by Evans, D.J. Bristow and A.L. Greer, in ‘Light 1998) pp. 963-968. PA, (TMS, Warrendale B. Welch 9:00 AM Nucleation Mechanisms of TiBAl Additions in Al-Ni-Si Alloys O’Reilly of Cambridge, Dept. of Matls. Sci. & Metallu., Pembroke St., Cam- of Cambridge, Dept. of Matls. Sci. & Metallu., bridge CB23QZ UK as the number of The efficiency of a grain refiner can be quantified product. Even for very grains per nucleant particle in the solidified it is known from effective refiners in aluminium, such as Al-5Ti-1B, at best 10 are very low, experiment that efficiencies Peter Schumacher 8:30 AM Introductory Remarks 8:35 AM Alloys–How to Im- Design of Grain Refiners for Aluminum Efficiency prove Sponsored by: Sponsored Program Organizers: Cast Shop Technology: Grain Technology: Shop Cast Refinement Thursday AMMarch 16, 2000 Mississippi Room: Corporation, GM Powertrain Group, Pontiac, MI 48340-2920 GM Powertrain Group, Corporation, Aluminum N. O’Donnell, Commonwealth USA; James of Engineering, Louisville, KY Corporation, Department 40202-2823 USA Session Chair: Division, Newburgh, IN 47630 USA, tions, Rigid Packaging Robards, KY Ctr., Alloys, Corp. Tech. Boone, KB G. W. 42452 USA

THURSDAY AM 185 Sachs modelfor the singlecrystal-polycrystalconversion factor. The sents thefiberreinforcementby ruleofmixtures,butalsoadopts of monolithicsinglecrystalsand fibers.Thismodelnotonlyrepre- cyclic stress-strainresponseofthe multicrystallinecompositestothose copper composites.Thepaperintroduces asimplemodeltolinkthe been conductedontungstenmonofilament reinforcedmulticrystalline Studiesoncyclicdeformation andfatiguefracturebehaviorhave Sci. andEng.,Philadelphia,PA 19104-6272 USA Chandler, AZ85226USA; Zhang ment-Reinforced MulticrystallineCopperComposites Cyclic DeformationandFatigueFracture ofTungsten Monofila- 8:30 AM Spain Materials iEnginyeriaMetallurgica,BarcelonaE-08028 Universitat PolitecnicadeCatalunya,Dept.Cienciadels Matls. Sci.&Eng.,Urbana,IL61801USA;L.Llanes, Session Chairs: March 16,2000 Thursday AM Engineering, Urbana,IL61801USA University ofIllinois,DepartmentMaterialsScienceand Engineering, Tempe, AZ85287-6106USA;J.K.Shang, University, Department ofMechanicalandAerospace Philadelphia, PA 19104USA;PedroD.Peralta,ArizonaState vania, DepartmentofMaterialsScienceandEngineering, Ontario Canada;CharlesMcMahon,UniversityofPennsyl- Department ofMetalsandMaterialsScience,Toronto, Program Organizers: Mechanical BehaviorofMaterials Critical Technology Sector, StructuralMaterialsDivision,Jt. Sponsored by: Engineering Materials Professor CampbellLaird:Fatigueof Materials; ASymposiuminHonorof Cyclic DeformationandFatigueof gauges. duced using5/1TiBAlathigherrollcastingspeedsandthinnercast grain structurerefinedbyTiCAl315 with 5/1TiBAlatequivalentTiadditionslevels.However,theas-cast 315 the rollcastsforcomparison.TheresultsofstudyshowthatTiCAl of Ti.Aconventionalgrainrefiner,5/1TiBAl,hasalsobeenusedin thickness, rollcastingspeed,superheatofthemeltandadditionlevel structure hasbeeninvestigated,inconjunctionwithvariationsstrip cast aluminiumalloys.Theeffectofthegrainrefineronas-cast London &ScandinavianMetallurgicalCoLimited,hasbeenusedinroll Anewcarboncontaininggrainrefiner,TiCAl315 pany Limited,Rotherham,EnglandUK England OX13PHUK; J. Bristow minium Alloys A StudyofTiCAl315 10:50 AM contribution tothestructuralrefinementobserved. mental apparatushavebeenalsoinvestigatedandfoundtono a specificvalue.Theeffectsofmechanicalvibrationstheexperi- range offrequencyandonlywhenthemagneticpressurehasexceeded  isequallyefficientintermsofgrainrefiningabilitycompared 1 ; CampbellLaird 2 ; 1 University ofOxford,Dept.Matls.,ParksRd., : Ming Yun ASM International:MaterialsScience J. K.Shang,UniversityofIllinois,Dept. 2 2 ; Location: OprylandConventionCenter Room: CanalA London &ScandinavianMetallurgicalCom-      Zhirui Wang, UniversityofToronto, 1 1 2 ; S.A.Lockyer Intel Corporation,5000W. ChandlerBlvd., GrainRefinementinRollCastAlu- University ofPennsylvania,Dept.Matls.  rodsisbetterthanthatpro- 1 ; J.D.Hunt  1 ; R.Cook producedby : Jieping 2 ; D. tion ofHaynes The Low-CycleFatigueBehaviorandMicrostructuralEvolu- 9:20 AM brittle. interface bondingstresswillbereducedandthematrixmore carbon coatinglayeroffiberandmatrixalloywereoxidizedthe ture inair,damageevolutionwasnearlythesame,butoutermost tests, theoreticalinvestigationhasbeenconducted.Athightempera- damage initiationandpropagation.Thatwhy, inadditiontofatigue tant. Thoseresultsshowhowimportanttheinterfaceregionisin high temperature,probablybecausedebondingappearedmoreimpor- same. However,forthesamelevelofstress,fatiguelifewaslongerat ing. Athightemperatureinvacuum,damageevolutionwasnearlythe outer carbonlayerandSiCfiber,fiberbreakage,matrixcrack- layer, crackingtheoutercarboninterfacialdebondingbetween layer, interfacialdebondingbetweenreactionlayerandoutercarbon damage evolutionprocessasfollows:crackinitiationatthereaction higher thanthattestedatroomtemperature.Attemperature perature. Butthefatiguedatatestedathightemperatureinvacuumis at hightemperatureinvacuumishigherthanthattestedtem- higher thanthattestedathightemperature.Butthefatiguedata ties. Sofar,fatiguetestswereconductedatroomtemperaturewas explain theeffectofinterfacialdamageonglobalmechanicalproper- composites toreducethiseffect.Butbeforethat,wemustable strong effectonglobalpropertiesloss.Finallyweaimtodevelopnew degrades fibersproperties.Moreoverthethicknessofthislayerhasa reaction layeroccursbetweenfibersandmatrixduringprocessing stability athightemperature.Butonemajorproblemstillremains: engines, becauseoftheirhighspecificmodulusandstrength,good posites areattractiveforstructuralapplicationssuchasgasturbine Silicon-carbide(SCS-6)fiberreinforcedtitaniumalloymatrixcom- Tsukuba, Ibaraki,Japan Fatigue Properties ofSiC/Ti-15-3 MMC 8:55 AM the fiberseemsineffectiveforimprovingfatiguelife. high plasticstrainamplitude,fatiguecracksinitiateatthefiber,and amplitudes andthefibergreatlyimprovesfatiguebehavior. Ata grain boundariesinthematrixatlowandintermediateplasticstrain depends onappliedplasticstrainamplitudes.Mostcracksinitiateat afterwards. Thefatiguefracturemechanismofthecompositeshighly breaks intotwosegments,thecompositewillfailinashortperiod such asgrainboundariesanddislocationstructures.Oncethefiber ture isverysensitivetoafiberbreak,andmicrostructuralfeatures, reinforced polycrystallinemetalmatrixcomposites.Thefatiguefrac- could beappliedtohigh-cyclefatigueofcommercialcontinuous-fiber- were fatigued.Thisencouragingoutcomesuggestthatthenewmodel experimental datainallstrainamplitudesatwhichthecomposites results calculatedbythemodelshowverygoodagreementwith the presenceofresidual coldworkresultingfrom the finalflattening exhibited cyclicsoftening atroomtemperatureisbelieved tobedue the coarseningofsecondphase particles.Thereasonthatthealloy the alloyexhibitedcyclicsoftening inmostcases,whichresultedfrom hardened atahighrateandthenreached aplateau.However, at1800 at allofthestrainrangesevaluated. At1200 was rapidat1600 tation ofsecondphaseparticles. Sincethekineticsofprecipitation of thealloyathightemperatureswasgreatlyinfluencedbyprecipi- tron microscopy(TEM)indicatedthatthemechanicalperformance crostructures bymeansofopticalmicroscopyandtransmissionelec- soften atthetemperaturesof1800 moderately hightemperaturesof1200 ure ofthealloy. Thealloywasobservedtocyclicallyhardenatthe range significantlyaffectedthemechanicalbehaviorandfatiguefail- 1800 studied atroomtemperature,75 Thelow-cyclefatiguebehaviorofHAYNES P.O. Box9103,Kokomo,IN46904-9013USA 37996-2200 USA; University ofTennessee, Dept.ofMatls. Sci.andEng.,Knoxville,TN Huang Y. -F. Liu ° ). Test resultsindicatedthatthetesttemperatureandstrain 1 ; L.Miller 1 ; 1 National ResearchInstituteforMetals,1-2-1Sengen,      1 ; C.R.Brooks ° F, thealloyexhibited noticeablecyclicalhardening HR-120 2 Haynes International,Inc.,1020W. ParkAve.,      Alloy 1 ° ; R.Seeley C andelevatedtemperatures(1200 ° F and75 : ° F and1600 P. K.Liaw : C. Masuda 2 ° ; D.L.Klarstrom ° F. Theanalysesofmi-  F, thealloycyclically HR-120 ° F, but tocyclically 1 ; Y. H.He 1 ; Y. Tanaka  alloywas 2 ; 1 ; M. 1 The ° ° F- F, 1 ;

THURSDAY AM 186 ; 1 ; D. 1 is a  Universitat L. Llanes 1 ; 1 : ; P. K. Liaw ; P. 1 ; M. Anglada 1 Haynes International, Inc., Haynes International, 2 ; C. R. Brooks 1 ; N. Salan 1 L. Jiang : Ispat Inland, Inc., 3001 E. Columbus Dr., East Ispat Inland, Inc., 3001 E. Columbus Dr., 1 Alloy ; M. T. Farre ; M. T. 1 ;      1 The University of Tennessee, Dept. of Matls. Sci. and Dept. of Matls. The University of Tennessee, 1 ; 2 cycles. The advantage of a high-frequency fatigue testing cycles. The advantage 9 Benda Yan ; A. Girones 1 : and 10 5 registered trademark of Haynes International, Inc. registered trademark of Haynes International, AM 11:50 Steels On the Fatigue Behavior of Duplex Stainless Chicago, IN 46312 USA mean stress effect in H900 temper. For a given temper at high strain at high given temper For a in H900 temper. stress effect mean did not strain ratios applied the three lives among the LCF amplitudes, stress relaxation of the mean as a result differences significant show gen- at R=-1 cyclic loading amplitudes, at low strain However, effect. as compared and longest LCF lives mean stress levels erated the lowest precipitation- obtained for this 0.5. The LCF life data to R=0 and of heat treat- combinations steel under various hardening stainless proposed life- correlated by two ratios could be well ments and strain approaches. assessment AM 11:25 Fatigue: The High-Cycle Fatigue Be- High Frequency Metal havior of ULTIMET L. Klarstrom USA; Eng., Knoxville, TN 37996-2200 IN 46904-9013 USA Box 9013, Kokomo, P.O. Park Ave., 1020 W. is a newly developed commercial Co-26Cr-9Ni alloy ULTIMET® resistance to both wear and corro- which exhibits good (wt.%) alloy, high-frequency fatigue testing system was used sion. A state-of-the-art alloy between fatigue behavior of ULTIMET® to study the high-cycle 10 in testing time, so that a great number of cycles system is the reduction alloy time. Fatigue behavior of ULTIMET® can be obtained in a short Hz and conventional was investigated at a high frequency of 1000 rate on fatigue crack frequency of 20 Hz. The effect of high strain The fractography initiation and propagation mechanisms was studied. fracture surface were studies showed that the main features of the fatigue specimens. similar for both high and conventional-frequency developed at both 1000 There were some differences on the S-N curve and conventional-fre- and 20 Hz. The variations between the high the surface microscopy. quency fatigue mechanisms were elucidated by indicated alloy Most of the fatigue fracture surfaces of ULTIMET® surfaces, and had a that the crack generally initiated on the specimen Research sup- crystallographic appearance regardless the frequency. Science Foundation ported by Haynes International, Inc. and National D. Durham and Ms. M. (DMI-9724476 and EEC-9527527 with Dr. that ULTIMET Poats as contract monitors, respectively). Note A. Mateo Materials i Enginyeria Politecnica de Catalunya, Dept. de Ciencia dels Diagonal 647, Barcelona E-08028 Spain ETSEIB, Av. Metallurgica, ferrite-austenite stain- Interest on the fatigue performance of duplex in recent years. This is less steels (DSSs) has expanded significantly within structural primarily due to the increasing use of these materials extensive fatigue test- applications that involve cyclic loading. Hence, and service-related ing and analyses, approaching both fundamental viewpoints, have been developed by several excellent research groups along the last fifteen years. The objective of this contribution is therefore to critically review such existing knowledge as well as to point out immediate and long-term needed information for continuous struc- In doing so, aspects deal- tural improvement involving DSSs to occur. ing with each and every one of the fatigue stages of these materials are addressed: cyclic stress-strain response and its correlation to substruc- tural evolution; influence of environment (gaseous atmosphere/aqueous media) and thermal aging on strain localization, crack nucleation and early growth, propagation of long cracks and number of cycles to failure; anisotropic behavior as related to given processing routes (induced microstructural and crystallographic texture); and fatigue endur- ance criteria, for both low- and high-strain amplitude regimes, in terms of the surface damage resulting from the corresponding mechanical coupling of the constitutive phases. Although the review is mainly driven by own results, in all cases attempts are made to consider reports found in the literature for related duplex and single-phase austenitic and ferritic steels. 12:15 PM Fatigue Behavior of Interstitial Free Steels with Deep Draw Strains Uni- 1 ; 1 National Central 1 ; 1 University Of Illinois at Ur- 1 ; William W. Gerberich W. ; William 1 ; 1 ; Chi Chih Chu 1 Jeffrey L. Evans Jeffrey ; Jian Ku Shang 1 : Chih Kuang Lin : Xiaoli Tan : University, Dept. of Mech. Eng., Chung-Li 32054 Taiwan University, This study investigated the effects of mean stress on the low-cycle fatigue (LCF) behavior of a martensitic precipitation-hardening stainless steel in different tempers. Uniaxial LCF tests were conducted under strain control with three strain ratios R=-1, 0 and 0.5. LCF specimens were prepared in three different tempers, namely solution- annealed (SA), peak-aged (H900), and overaged (H1150) conditions. The effects of aging treatment on the LCF behavior are also discussed. Experimental results show that LCF specimens in these three tempers all exhibited cyclic softening at high strain amplitudes under a strain ratio of R=-1. At low strain amplitudes, the cyclic softening is less evident for SA and H900 temper while H1150 temper exhibits cyclic hardening. Under a strain ratio of R=-1, specimens in H900 temper had longer LCF life than those in SA and H1150 tempers. However, this advantage for H900 over SA and H1150 tempers disappeared at higher strain ratios (R=0 and 0.5) due to the greater sensitivity to bana-Champaign, Dept. of Matls. Sci. and Eng., 1304 W. Green St., 1304 W. bana-Champaign, Dept. of Matls. Sci. and Eng., Urbana, IL 61801 USA of electric, electrome- Ferroelectric ceramics are used in number inherent electromechani- chanical and electrooptic applications. The highly susceptible to fa- cal hysteresis in these ceramics make them from purely mechanical, tigue. The fatigue degradation may result fatigue crack growth purely electric or combined loading. In this study, in a lead zirconia titanate driven by pure electric loading was examined growth behavior was and a La-doped lead zirconia titanate. Crack field, field strength, found to depend on direction of the applied electric hysteresis loop. temperature, and size of the the field ratio, frequency, Analysis of the experimental results using the current fracture mechanics principles will be presented and comparison will be made between theoretical predictions and experimental observations. AM 11:00 Low-Cycle Fatigue Behavior of a Precipitation-Hardening Stainless Steel versity of Minnesota, Chem. Eng. and Matls. Sci., 151 Amundson versity of Minnesota, MN 55455 USA SE, Minneapolis, Ave. Hall, 421 Washington to reversed bending fatigue cycling, was evalu- Surface damage, due the number of fatigue cycles in the low-cycle ated as a function of stainless steel and a 316 stainless steel. Using fatigue regime for a 310 were inves- an atomic force microscope (AFM), surface displacements slip band formation and tigated. These displacements were a result of at the free surface. The subsequent extrusions and intrusions occurring steel, a relatively stable cumulative surface damage of the 316 stainless steel, a very stable was compared with that of the 310 stainless alloy, of strain-induced martensite or if any, determine what effect, to alloy, When predicting stacking fault energy on the surface displacements. displacement due to slip fatigue crack initiation, the amount of surface models of a band evolution is critical, therefore previous low cycle fatigue were microstructurally-based Manson-Coffin law of tested. 10:10 AM Break 10:35 AM in Ferroelectric Ce- Cyclic Electric Field-Driven Crack Growth ramics operations of the plate. It was observed from the SEM examination of examination from the SEM observed plate. It was of the operations varied sites of crack initiation number that the surfaces the fracture oxida- highest temperatures, range. At the and strain with temperature work This in crack initiation. role play an important found to tion was the also acknowledge Ind. We by the Haynes International is supported Division of Science Foundation, the of the National financial support No. DMI- Innovation, under Grant and Industrial Design, Manufacture, Pro- Development the Combined Research-Curriculum 9724476, and Knox- University of Tennessee, EEC-9527527, to the gram, under Poats as program Durham and Ms. Mary Delcie R. Dr. ville, with of the appreciate the financial support We managers, respectively. and Office of Research Administra- Center for Materials Processing at as directors, respectively, Walker and K. tion with Drs. C. McHargue the University of Tennessee. 9:45 AM Damage of 310 and 316 Stainless Steels Cumulative Fatigue Evaluated by AFM

THURSDAY AM 187 Almeida MSW IncinerationPlant Characterisation andThermal Treatment ofFly-Ash froma 9:00 AM based oneconomics. of therecoverysequencechosen fortheproductswillbedescribed to direct-reducediron[DRI]willalso bediscussed.Criticalassessment problems associatedwiththeuseofreducedred-mudasanalternative ery andtheplansfortitaniumoxiderecoveryfromred-mud.The sentation willdescribethesuccessfuleffortsofironandaluminarecov- cantly highjustifyingitsrecoverybyanacid-leachprocess.Thispre- smelted, theconcentrationoftitaniumoxideinslagwillbesignifi- the tuyeresinanironblastfurnaceorsmeltedtoproducepigiron. If tion ofover94pct.Atthisstage,theproductcouldbechargedthrough Hematite canbecarbothermicallyreducedwithadegreeofmetalliza- recovered fromred-mudbysoda-ashsinteringandcausticleaching. nium oxide.Ithasbeenshownthatover90wt.pct.aluminacan be produced fromJamaicanbauxiteisrichinhematite,aluminaandtita- red-mud isproducedforeverytwotonsofbauxitemined.The bauxite [BayerProcess]isknownasred-mud.Approximately, atonof Themajorwasteproductofthealkalineextractionaluminafrom Gramercy, LA70052USA USA; Mines, Metallu.&Matls.Eng.,1500IllinoisSt.,Golden,CO80401 Mud Pyrometallurgical ExtractionofAluminaandIronfromRed 8:30 AM Henderson, NV89015USA Stephen Fox,TIMET, HendersonTechnical Lab., Center, Office ofFossilEnergy, Albany, OR97321USA; Session Chairs: Room:JacksonA/B March 16,2000 AM Thursday 83843-3024 USA Department ofMetals&MiningEngineering,Moscow, ID 80401-1887 USA;PatrickR.Taylor, Universityof Idaho, of Mines,KrollInstituteforExtractiveMetals,Golden,CO Program Organizers: Treatment &MinimizationCommittee Sponsored by: Treatment &Minimization:II High Temperature Processes forWaste fatigue fracturebehaviorofthesteelstestedisalsodiscussedindetail. similar despitetheirsignificantlydifferent SWEsusceptibility. The deep drawnstrains,thefatiguelivesofIFsteelsandnon-IFsteelare bending fatigueconditions.Limitedtestresultsshowthatevenwith less than-60 -40. Thenon-IFsteel,DQSK,isnotSWEsusceptiblewithaDBTTof very highDBTT, 20 tibility onthefatigueperformance.OneofIFsteelsexhibiteda steels andanon-IFsteelweretestedtostudytheeffectofSWEsuscep- mance oftheIFsteelshasbeenaseriousconcern.Inthisstudy, twoIF cyclic loading,theeffectofSWEsusceptibilityonfatigueperfor- automotive bodystructuresandevenpanelsaresubjectedto Since IFsteelshavebeenwidelyusedinautomotiveindustryandmany tures whentheductilebrittletransitiontemperature(DBTT)ishigh. ing failureofdeepdrawnpartsunderimpactloadingatwintertempera- such ascarbonandnitrogen.TheSWEsusceptabilitymaycausecrack- Secondary Work Embrittlement(SWE)duetoitslackingofinterstitials, Itiswellknownthatinterstitialfree(IF)steelsaresusceptibleto : 2 Kaiser Aluminum&ChemicalCorporation,P.O. Box3370, Brajendra Mishra 2 ; 1 Escola SuperiorAgrária deCoimbra,Dep.Ciencias Exactas ° C. Specimenswithdeepdrawnstrainsweretestedunder Extraction &ProcessingDivision,Waste William K.O’Connor, AlbanyResearch ° C, whereastheotherexhibitedmuchlowerDBTT, Location: OprylandConventionCenter 1 Brajendra Mishra,ColoradoSchool ; DavidKirkpatrick : Célia MariaFerreira 2 ; 1 Colorado Schoolof 1 ; ManuelFonseca cling Processes A FundamentalStudyofAg-Sb-SnAlloysduringSilverRecy- 10:15 AM 10:00 AMBreak range of1300-1600 ing, viscosity, densityandelectricalconductivity, inthetemperature Database ofmeltpropertiesathighertemperatures,suchaspartition- nants, andincreasedcorrosionerosionofmeltercomponents. places furtherconcernsontheincreasedvolatilizationofcontami- neous wastestreams.However,theincreasedprocessingtemperature creased wasteloadingandbeingapplicabletovariableheteroge- tion techniqueshavetheadvantageofincreasedthroughputrate,in- ents intoitsnetworkstructure.Alternativehightemperaturevitrifica- due toitsdurabilityandabilityacceptavarietyofwasteconstitu- Glassisusedforimmobilizationofradioactiveandhazardouswastes Hall, Moscow, ID83844-3024USA e doAmbiente,Bencanta,Coimbra3040-316Portugal; chazabite wasmostfavored. and Freundlichequationsindicate thattheadsorptionofchromiumon intra-particle diffusion.AdsorptionconstantscalculatedfromLangmuir for sorptionofchromiumwasproposedintermsadsorptionand maximum removalofchromiumwereidentifiedandthemechanism investigated forthesorptionofchromium.Optimalconditions for zeolite namely:chabazite,erionite,mordeniteandclinoptilolitewere solution, time,andtypeofzeoliteusedwasstudied.Fourtypes of from solutionsusingzeoliteswasundertaken.TheeffectofpH the metals fromthesolutions.Inthisstudyremovalofchromium national prioritytofindwaysandmeansremovetheharmfultoxic portable watersystemorfarmfieldsifdisposedasis.Itistherefore a these wastessincetheymaycauseincalculableharminthenations dionuclide wastes.Thereisagrowingconcernoverthedisposal of Radioactivecomponentsprocessingfacilitiesgeneratealotof ra- 35487-0202 USA MTE Dept.,A129BevillBldg.,P.O. Box870202,Tuscaloosa, AL Ignatius C.Okafor Removal ofChromium from IndustrialWaste Solutions 10:45 AM during theremovalprocesswillalsobediscussed. Sn alloyswillbediscussed.CharacteristicsinthebehaviorofSband fundamental studiesontheremovalofantimonyandtinfromAg-Sb- by evaporationandoxidation.Inthepresentpaper,resultof lurgically, wheretheimpuritiessuchasantimonyandtinareremoved bility. Thematerialsareconcentratedandthentreated pyrometal- because ofitsincreaseintheprintingpapertosuppressinflamma- the antimonycontentinthesewastesisincreasedrecentyears Silver wastestreatedherearemainlyfromphotographindustrieswhere dertaken byTokai UniversityandMatsudaSangyoCo.,Ltd.inJapan. Acooperativeresearchworkonthesilverrecyclingprocessisun- Ltd., Iruma,Saitama358-0032Japan Kanagawa 259-1292Japan; Itaru Jimbo Patrick R.Taylor Laboratory Research forHighTemperature Vitrification 9:30 AM ment underdifferentconditionsarealsopresented. results ofcontaminantsremovalfromthisresiduebythermaltreat- is characterised,namelybyusingNEN-7343leachingprotocol.Also, paper asampleoffly-ashesfromsemi-dryoff-gastreatmentsystem taminants canbeviewedasanimportantstepofitstreatment.Inthis pounds. Thus,detoxificationaccomplishedbyremovingthesecon- metals, chloridesandsometimesminorquantitiesoforganiccom- sidered hazardouswasteduetoitshighconcentrationofsolubleheavy Fly-ashesfromMunicipalSolidWaste IncinerationPlantsarecon- Engenharia, Demm,RuaDosBragas,Porto,Cedex4099Portugal 1 ; : Yasushi Akahori 1 Tokai University, Dept.ofMetallu.Eng.,Hiratsuka, 1 ; 1 ; ° 1 University ofIdaho,Metallu.Eng.Dept.,McClure C arebeingdeveloped. Ramana G.Reddy 2 Musashi Factory, MatsudaSangyoCo. 1 ; FumikoNakai 1 ; 1 The UniversityofAlabama, 1 ; Tsuyoshi Kamata 2 Faculdade de 2 : : ;

THURSDAY AM 188 ; : 1 Dongwha Kum ; 2 Hong-Ik University, Matls. Sci. Hong-Ik University, 2 Naval Postgraduate School, Dept. School, Postgraduate Naval 1 ; : Woo-Jin Kim : Woo-Jin 1 The University of Michigan, Dept. of 1 ; 1 ; D. H. Bae 1 Terry R. McNelley Terry : Korea Institute of Science and Technology, Matls. Eng., P.O. Box 131 Matls. Eng., P.O. Korea Institute of Science and Technology, Cheongryang, Seoul 130-650 Korea; 121-791Korea & Eng., 72-1 Sangsoo-dong, Mapo-ku, Seoul aluminum alloys Superplastic behavior of dispersion strengthened at high strain and discontinuously reinforced aluminum composites the concept of threshold rates has been interpreted by incorporating temperature depen- stress, and the threshold stress exhibits strong The threshold stress data in literatures fit well with an Arrhenius- dency. meaning of the thermally type plot, and however the origin and exact In this paper, a activated process have not been fully understood. stress for super- possibility of structural dependency of the threshold the grain size as a plasticity has been investigated. By considering threshold stress data for structural factor, it is demonstrated that the grain sizes and al- many superplastic aluminum alloys with different a modulus compensated loying chemistry fall into a narrow band in This analysis leads to a threshold stress vs. grain size correlation. exponent of -1.1 for phenomenological equation with the grain size aluminum alloys. the threshold stress behavior in superplastic 10:00 AM Invited Dependence of Superplastic De- Grain Size and Temperature formation in an Al-Mg Alloy Under Isostructural Condition of Mech. Eng., 700 Dyer Rd., Monterey, CA 93943-5146 USA CA 93943-5146 Monterey, Dyer Rd., Eng., 700 of Mech. deformation ductility during tensile is exceptional Superplasticity rate condi- temperature and strain under appropriate of a material research in elevated tem- preeminent Oleg Sherby’s tions. Professor in estab- materials was instrumental of metallic perature deformation to the relationships applicable microstructure-property lishing the high strain prerequisite for it is a A of superplasticity. phenomenon flow stress, which requires deformation under rate sensitivity of the boundary sliding is the principal deformation conditions where grain of the sliding by either slip or diffu- mechanism, with accommodation the microstructure must be highly refined, sional processes. For this, to and mobile boundaries that are resistant with equiaxed, stable grains necessary grain refinement in bulk aluminum tensile separation. The only by recrystallization after plastic deforma- alloys may be achieved routes that enable superplastic tion and two distinct recrystallization alloys have been identified. The present under- response in aluminum control by deformation and recrystalliza- standing of microstructural will be reviewed. Results of investigations into tion of aluminum alloys microtextures and grain boundary the evolution of microstructures, by means of computer-aided electron back- misorientation distributions for alloys representing scatter diffraction (EBSD) analysis methods and implications to each of these different routes will be summarized will be discussed. processing of Aluminum alloys for superplasticity 9:40 AM Invited Stress for Superplas- The Effect of Grain Size on the Threshold tic Flow in Aluminum Alloys 1 Amit K. Ghosh Matls. Sci. and Eng., Ann Arbor, MI 48109 USA Mechanical behavior of a superplastic Al-4.7%Mg-0.8%Mn-0.4%Cu alloy has been characterized by a new type of step strain-rate test which preserves the initial microstructure of the alloy (i.e. an isostructural test). Four different grain sizes of the alloy (8 to 30?m), prepared by variations in thermomechanical processing practice were examined. A sigmoidal relationship between log? and log? is observed for each isostructural condition. The value of maximum m? increased with increasing temperature and with decreasing grain size. The isostructural log? vs. log? data are evaluated using the grain-mantle based quantitative model proposed by Ghosh. In the dislocation creep region?, stress exponent is 4.55 and activation energy is close to that of lattice self-diffusion, but grain size exponent is non-zero (~ 0.37). In the grain mantle deformation region?, the value of stress exponent based on effective stress (s -so, where so is threshold stress) is ~ 1.7, and grain size exponent is 2.3; but interestingly activation energy is the same as that for dislocation creep. Grain mantle creep is now believed to be controlled also by dislocation glide and climb processes, but its rate is enhanced many times due to a high concentration of vacancies near grain boundaries. Computed so based on the model 9:20 AM Invited 9:20 AM Alumi- in Superplasticity and Recrystallization, Processing, num Alloys ; ; 2 1 Kenji Higashi : ; Soon-Hyung Hong 1 Woo-Jin Kim Woo-Jin : (Positive Exponent Superplasticity). Al- Eric M. Taleff, University of Texas, University Eric M. Taleff, Room: Bayou E Convention Center Location: Opryland 0s?1 ) are not yet fully understood, some interesting -2s?1 Terry McNelley, Naval Postgraduate McNelley, Terry Structural Materials Division, Materials Materials Division, Structural Hong-Ik University, Sangsu-dong Mapo-ku, Seoul 121-791 Korea; Hong-Ik University, Korea Advanced Institute of Science and Technology, Matl. Sci. and Korea Advanced Institute of Science and Technology, Osaka Prefecture University, Dept. of Metallu. and Matls. Sci., Col- Osaka Prefecture University, Eng., Kusung-dong Yusung-ku, Taejon 373-1 Korea Taejon Eng., Kusung-dong Yusung-ku, Deformation behavior of high-strain-rate superplastic PM 2124 Al alloy and PM 20%SiCp/2124 Al composite was investigated over a wide range of temperature from 643 to 838K. The entire temperature range of investigation could be divided into two regions where grain boundary sliding (high-temperature range from 748 to 838K: Region I) and dislocation climb creep (low-temperature range from 643 to For the 2124 respectively. 693K: Region II) dominate the plastic flow, for Region I and II were close to the true activation energies Al alloy, that for the lattice diffusion in pure aluminum, QL. For the composite, however, true activation energy for Region I was considerably higher than QL, while the energy for Region II was close to QL. The grainsize compensated strength comparison indicates that composite is stronger than the unreinforced PM 2124 Al alloy in Region II but weaker in Region I. The threshold-stress behavior was investigated as a function of temperature. 1 2 lege of Eng., 1-1, Gakuen-cho, Sakai, Osaka 599-8531 Japan lege of Eng., 1-1, Gakuen-cho, Sakai, Osaka can be found Recent studies have demonstrated that superplasticity at strain rates over 10 positive-exponent super- though the detailed mechanistic origins of (superplasticity found at plasticity or high-strain-rate superplasticity strain rates over 10 Higashi et al Recently, experimental observations have been noted. grain boundary sliding is proposed a model in which it is assumed that but superplasticity, the dominant deformation process, as in normal as a liquid phase at the with the present of accommodation helper such the stress concentra- interfaces or boundaries serving both to relieve up of internal cavitation tions due to sliding and to restrict the build In the current presenta- and subsequent failure by cavity interlinkage. and further evi- tion, the previously reported data will be reviewed mechanisms in dence will be presented to discuss the deformation Finally the opti- positive exponent or high-strain-rate superplasticity. distribution of the ac- mum design in microstructural control for the refinement is demon- commodation helpers as well as the grain size superplastic ma- strated for the positive exponent or high-strain-rate terials. 9:00 AM Invited High Strain-Rate Superplasticity of 2124 Al Alloy and SiC 2124 Al Composite Reinforced 8:30 AM Keynote Overview of Positive-Exponent Superplasticity 1 Thursday AM Mechanical Engineering Department, Austin, TX 78712- Mechanical Engineering Lawrence Livermore National Lesuer, 1063 USA; Donald R. CA 94550 USA; Chol K. Syn, Livermore, Laboratory, & Manufacturing National Laboratory, Lawrence Livermore Division, Livermore, CA 94550 USA Materials Engineering March 16, 2000 Session Chair: CA 93943-5000 USA Monterey, School, Mech. Eng., Processing and Manufacturing Division, Structural Materi- Division, Structural and Manufacturing Processing Committee Shaping and Forming als Committee, Organizers: Program Sponsored by: Sponsored Honorary Symposium for Professor Symposium Honorary B Sherby: Superplasticity Oleg D.

THURSDAY AM 189 the alloy. Detailed experimentalproceduresand the resultsoftheir construct apartial forminglimitdiagramforsuperplastic formingof performed on-site,andotherdata from literaturesourceswereusedto ments onthecircle-griddedsamples, thedatafromtensiletests temperature usinguniaxialtensile samples.Thelocalstrainmeasure- tion obtainedfromthestrainrate changetestsperformedatthesame forming wereshowntocloselyfollow theflowstress-strainraterela- flow stressesandstrainratesdeveloped atthetopofdomeduring major strainsweremeasuredaftertheformingwasperformed.The were etchedwithcirclegridspriortotheforming,andlocalminor different formingandbackpressuresapplied.Severalconesamples dome heightsofthehemispheresandconesweremeasuredfor the designed andbuiltbiaxialformingapparatus.Thetemporalchange of pressure. Theformingoperationwasperformedusinganin-house spheres andconesatconstantformingpressureswithwithoutback SuperplasticAl5083alloydisksweregas-pressureformedtohemi- Stanford, CA94305USA CA 94551-0808USA; Livermore NationalLaboratory, P.O. Box808,L-342,Livermore, Alloy An AnalysisofGasPressureFormingSuperplasticAl5083 11:10 AMInvited AC06-76RLO 1830. Energy Sciences,U.S.DepartmentofunderContractDE- sliding. Work supportedbytheMaterialsDivision,Office ofBasic peratures thematerialfailsduetoinsufficientaccommodationof that theSnisincreasingGBSunderallconditions,butatlowertem- liminary microstructuralexaminationofquenchedsamplesindicate failure wasincreasedfrom600%to740%bytheadditionofSn.Pre- strain rates.At550 taining Snshowedconsistentlyhigherelongations,particularlyatlow Sn material.Attemperaturesof500 the Al-Mgalloytoa“quasi-brittle”intergranularfailureinAl-Mg- it wasnotedthatthefracturesurfacechangedfromanarrowpointin both coarse-andfine-grainedAl-Mgalloys.Incoarse-grainedsamples the presenceofSnhadanegativeimpactonelongationtofailurein amounts upto10at.%priortesting.Attemperaturesbelow500 showed thattheSnsegregatedtoboundariesandwaspresentat Auger Microprobemeasurementsofgrainboundarycomposition Mg alloyswithandwithouttheadditionof80appmSn.Scanning suring deformationbehaviorandgrainboundarycompositioninAl- are investigatingtheroleofsoluteatomsontheseprocessesbymea- grain boundarydiffusion andlocalizedmovementofdislocations.We is stillbeingdebated,therearecertainlymajorcontributionsfrom of grainboundarysliding(GBS).ThoughtheexactmechanismGBS Fine-grainedsuperplasticdeformationisdominatedbytheprocess 99352 USA west NationalLaboratory, MSINP8-16,P.O. Box999,Richland,WA John S.Vetrano Influence ofSoluteAdditionsonSuperplasticDeformation 10:50 AMInvited tion atboundariesonsuperplasticdeformationandcavitation. the purposeofthispapertorevieweffectsimpuritiessegrega- sites fortheaccumulationofimpurities,i.e.boundarysegregation.Itis This rolepertainstotheabilityofboundariesserveasfavorable other importantroleplayedbyboundariesduringsuperplasticflow. ary sliding.Recentanalysesandexperimentaldatahaverevealedan- their abilitytocontributedeformationthroughtheprocessofbound- indicated thatboundariesplayanimportantrolewhichisrelatedto rates measuredduringsuperplasticflowtochangesingrainsize,has requirement alongwiththestrongsensitivityofsteady-statecreep requires astableandequiaxedgrainsizeoflessthan10 Theoccurrenceofmicrograinsuperplasticityinmetallicsystems Eng. andMatls.Sci.,Irvine,CA92697USA Mohamed Impurity SegregationduringSuperplasticFlow 10:30 AMInvited 10:20 AMBreak temperature. shows thatsoincreaseswithincreasinggrainsizeanddecreasing : Chol K.Syn 1 ; 1 University ofCalifornia,Dept.Chem.andBiochem. 1 ; C.H.Henager 1 ° ; DonaldR.Lesuer C andastrainof1x10-4s-1theelongationto 2 Stanford University, Matls.Sci.andEng., 1 ; S.M.Bruemmer ° C and550 1 ; OlegD.Sherby ° C, thematerialcon- 1 ; : 1 Pacific North- Farghalli A. 2 ; 1 µ Lawrence m. This ° C : Industrial Practice tals andPractice:Microstructure& Liquid MetalAtomization:Fundamen- analyzed forapplicationtothedesignoffuturecommercialalloys. Al-Mg alloysandpureAl.Theeffectsofternaryalloyingadditionsare This articlepresentsthesedataincomparisonwithfrombinary well aslow-impurity, ternaryAl-MgalloyscontainingMn,Fe,andZn. Recent investigationshaveproduceddataforcommercialalloysas repeatedly incommercialAl-Mgalloysdeformedbysolute-dragcreep. which itaffords. Tensile ductilitiesinexcessof100%areachieved study, yetisof practical significancebecauseoftheenhancedductility Solute-drag creepinmorecomplexAl-Mgalloyshasreceivedless lished modelshavebeensuccessfulinpredictingobservedbehavior. impurity, binaryAl-Mgalloysareavailableintheliterature,andestab- solubility attemperature.Detailedstudiesofthisbehaviorinlow- magnesium concentrationsfromaslittle2wtpcttothelimitof Solute-dragcreepisobservedinmanyaluminumalloyscontaining USA 1 in Aluminum-MagnesiumAlloys ofTernaryThe Effect AlloyingAdditionsonSolute-DragCreep 11:30 AMInvited Laboratory undercontractW-7405-ENG-48. the U.S.DepartmentofEnergybyLawrenceLivermoreNational analyses willbepresented.Work wasperformedundertheauspicesof that isusuallynot includedinprocessmodels.Similarly, thestrong droplet sizeisoneconsequence of thestochasticnucleationprocess nucleation temperatureaboutarange of10 populations orwithsingledroplet samples.Thevariabilityofthe most effectivelyincontrolledundercooling measurementsondroplet let structureformation.Thenucleation behaviorcanbeevaluated ation catalystsplayamajorrolein determiningthevariationindrop- a probabilisticprocessandtheactivity ofvariousheterogeneousnucle- coating development.Inthesecases,thebasicnatureofnucleation as droplet structureduringanumberofprocessesincludingdepositionand morphology thatdevelopinflightarealsokeyfactorsdetermining behavior, theresultingnucleationonset,andsolidfraction nal cooling,butalsoduetoliquidundercooling.Theundercooling The thermalhistoryisaffectedbydropletsizenotonlyduetoexter- nent ofthesolidificationbehaviorandmicrostructuredevelopment. nucleation catalysts,dropletthermalhistoryisanimportantcompo- Following subdivision,whichalsoservestoisolateeffectivelyinternal dispersal ofaliquidvolume(i.e.stream)intocollectiondroplets. Anessentialcharacteristicofliquidatomizationprocessesis the Sci. andEng.,1509UniversityAve., Madison,WI53706USA Jason L.Sebright Solidification ofAtomizedLiquidDroplets 8:30 AMInvited Naval ResearchLaboratory, Washington, DC20375USA Ames Lab.,Ames,IA50011-3020 USA;StevenP. Marsh, Session Chairs: March 16,2000 Thursday AM NIST, Gaithersburg, MD20899-8556USA Gaithersburg, MD20899-8556USA;StephenD.Ridder, Washington, DC20375-5343USA;FrankBiancaniello,NIST, Laboratory, MaterialsScienceandTechnology Division, Program Organizers: Division, PowderMetallurgyCommittee Sponsored by: The UniversityofTexas, TXMatls.Instit.,Austin,78712-1063 1 ; PeterG.Höckel Materials ProcessingandManufacturing Iver E.Anderson,IowaStateUniversity, Location: OprylandConventionCenter Room: BayouB Khershed P. Cooper, NavalResearch : 1 ; Eric M.Taleff 1 University ofWisconsin,Matls. ° C ormoreevenforafixed : John H.Perepezko 1 ; PeterJ.Nevland 1 1 ; ;

THURSDAY AM 190 : Valimet, 1 ; ; Rocco A. 1 1 ; Robert L. 1 Crucible Mate- 2 ; Jason Ting 1 David D. Leon ACuPowder International, LLC, ACuPowder International, : 1 ; Roy W. Christensen ; Roy W. 1 ; 1 Alcoa, Inc., Alcoa Tech. Ctr., Ingot & Ctr., Alcoa, Inc., Alcoa Tech. 1 ; 1 ; Michael J. Peretti ; Michael J. 1 ; Edul M. Daver 1 George T. Campbell T. George : Crucible Materials Corporation, Crucible Rsch. Ctr., 6003 Rsch. Ctr., Corporation, Crucible Crucible Materials 1 ; Diana K. Denzer 1 ; 2 William B. Eisen William : Kozarek Solid. Platform, 100 Technical Dr., Alcoa Center, PA 15069-0001 PA Alcoa Center, Dr., Solid. Platform, 100 Technical USA of Industrial Technology The U. S. Department of Energy-Office (DoE-OIT) has an objective to increase energy efficiency and enhance objec- support this competitiveness of American metals industries. To tive, Alcoa, Inc. entered into a cooperative program to develop spray forming technology for aluminum. Alcoa has developed spray forming processes capable of scale-up for commercial production of aluminum alloy sheet products. This paper will review research with linear nozzles and the effect of nozzle system geometry and operating parameters on the as-cast deposit. Emphasis will be given to Al 6111 a commercially For completeness, Alcoa significant alloy in the automotive industry. research in computer process simulation, thermo-mechanical processing techniques, and economics will also be covered. Longo USA; 15205-1022 PA Rd., Pittsburgh, Campbells Run Rd., Oakdale, Met., 1001 Robb Hill Crucible Compact. rials Corporation, 15071 USA PA operation of to improve the has two long term objectives Crucible (2) 1) improve the yield of finer powder and its production atomizers: CFD The use of any loss of productivity. produce finer powder without a pressure testing as a guide to the design of simulations and aspiration achieve these objectives is described. Data from gas delivery system to are presented and compared with the cur- the initial production trials on a 800 lb. and a 5500 lb. atomizer. rent production methods 10:55 AM Invited Atomizing Modes for Metal Powders Synopsis of Commercial Krishna B. Patel 07083 USA Union, NJ 901 Lehigh Ave., in the business of producing non-ferrous A Cu Powder is engaged processes methods of atomizing years. Various metal powders for 65 Essentially all processes were de- this facility. have been practised at this paper will character- veloped in house over the years. In general, modes used to atomize ize merits of vertical, horizontal and downward Original patent for metal powders. Specific examples will be narrated. by the founder of the the atomization of aluminuim powder invented powder will atomization of copper company will be addressed. Water information). The effects be described (without divulging proprietary characteristics of copper of some of the process variables onto the will also be described. powder for use into targeted market segments AM Invited 11:20 Aluminum Powder Commercial Atomization Processes for Manufacture Box 6186, 431 Sperry Rd., Stockton, CA 95206 USA O. Inc., P. powder manufac- Commercial atomization processes for aluminum inert gas atomization. ture range from air atomization to closed loop the surface chemistry of The shape of the particle produced as well as upon the atomization the particle will vary significantly depending shape, and surface chem- process used. Particle size distribution, particle response in subsequent istry can have a significant impact on the This paper discusses the various commercial processing of powder. the characteristics of atomization processes currently in practice and the powder produced by these processes. AM Invited 11:45 Spray Formed Alumi- Research in Nozzle Systems to Produce num Automotive Sheet Products 10:15 AM Break 10:15 AM Invited 10:30 Tri- Atomization with Production Interaction Simulation CFD als Universita’ 1 K. S. (Sim) ; 1 : ; Emilio Ramous 1 Hoeganaes Corporation, 1001 Taylors 1 ; 1 Chalmers University of Technology, Dept. of Chalmers University of Technology, 1 ; Brando Badan 1 ; 1 ; C. T. Schade ; C. T. 1 Lars Nyborg Andrea Zambon : : Ln., Cinnaminson, NJ 08077 USA Liquid metal atomization to produce particulates of definite size and shape distribution has advanced significantly during the last 30 prealloys powders of iron, stainless steel, and various years. Currently, of iron with chromium, manganese, nickel and molybdenum are rou- tinely being produced to satisfy the needs of $6 billion parts industry. This presentation will cover various types of powder produced by water atomization and the advances in manipulation of particle morphologies by controlling atmosphere, molten metal, jet geometry and other parameters. Eng. Mets., Horsalsvagen 7, Gothenburg SE41296 Sweden Eng. Mets., Horsalsvagen 7, Gothenburg SE41296 of powder, the surface Due to the high surface area to volume ratio factor that determines condition of powder is a crucially important Good processing control the use and further processing of the powder. surface contamination and powder handling procedures ensure that However, despite the (e.g. surface oxides, etc.) is kept at a minimum. during atomization, clean conditions and high cooling rates employed interest to be able to surface reactions will take place. It is of general the fundamental aspects describe these reactions and to understand scope of this commu- behind the formation of reaction products. The this subject based on nication is to provide a general overview on analysis (XPS, AES, observations made by means of surface chemical Discussion will focus on the SIMS, etc. of atomized high-alloy powder. surface reactions with role of atomisation method (gas or water), surface reactions with external impurity elements (e.g. oxygen), and to surface segregation internal impurity elements (e.g. sulphur) due amount of different reac- phenomena. Factors controlling the possible will be placed on tion products will be discussed and special attention that occur during atomi- how to distinguish between surface reactions zation and powder handling. Some general conclusions are as follows. i) Strong oxide formers (such as Si, Mn, Al and Cr) are oxidized at high temperatures during atomization. ii) The base element (Fe or Ni) is mainly oxidized during cooling and subsequent powder handling. iii) Surface oxidation is controlled by oxygen availability during gas atomization, while cooling rate is rate-controlling during water atomization. iv) Particulate reaction products may form on the powder surfaces rather than layered products. v) Surface segregation of e.g. S depends on competing events such as surface oxidation. 9:50 AM Invited Metals and Alloys Atomization of Ferrous Water di Padova, Dept. of Mech. and Mgmt. Innov., Via Marzolo 9, Padova Via and Mgmt. Innov., di Padova, Dept. of Mech. 35131 Italy are gaining much interest in view of their Nanostructured materials A common way of obtaining such a mi- high mechanical properties. by devitrification of an amorphous alloy crostructure is to induce treatment. Amorphization can be accom- means of a suitable heat processes or by stimulating solidifica- plished by rapid solidification in bulk samples of suitable composition. Gas tion at high undercooling both high cooling rates and relatively high atomization can produce the cooling rate experienced by the atomized undercooling extents. As size, both amorphous and nanostructured particles depends on their an atomization batch if an amorphizable alloy powder can be found in morphologies obtained in gas atomized is processed. The solidification of X-ray diffraction, zirconium base alloys, investigated by means their size and with com- SEM and TEM examination, are related with puted cooling rates. 9:25 AM Invited During Atomi- Powder Surface Microchemistry and Reactions zation Narasimhan dependence of liquid lifetime on droplet size in both fully liquid and fully liquid size in both on droplet lifetime of liquid dependence Models are potency. nucleant related to is directly solid states partially droplets atomized activity in nucleant to describe development under sup- strategies. The modeling process in overall be included that can are ARO (DAAG55-97-1-0261) (DMR-9712523) and port of NSF gratefully acknowledged. 9:00 AM Alloy Pow- Amorphizable in Gas Atomized Nanostructures ders

THURSDAY AM 191 ing rapidlydueto theintroductionofnewairpollution regulations, Theuseofmagnesiumalloysin theautomotiveindustryisexpand- Sheva 84100Israel; Industries Limited,DeadSeaMagnesium Ltd.,P. O.Box75,Beer- AZ31, ZK60 Deformation Characteristics of WroughtMagnesiumAlloys 9:20 AM cussed. derived. Therelevanceoftheseresultstoindustrialprocessingisdis- determined. Themicrostructuredevelopmentatvariousdepthswere perature andstrainratealonglinesat1/4,1/2,3/4,fullradiuswere lines frombillettoextrudatewereplottedandthevariationoftem- surface crackingwasestimatedfromthemeasuredductility. Stream- these variablesoccurredatthedieexitcornersothatoccurrence of 5 mm/sandinserttemperaturefrom300to450 rate andstressthroughoutthebilletforextrusionratio31,ramspeed kJ/mol enabledcalculationofthedistributionstemperature,strain the sinh-Arrheniusconstitutiveequationwithactivationenergy145 served byopticalandscanningelectronmicroscopy. Applicationof dynamic recoveryandrecrystallizationastemperaturerosewereob- dence oftwinningacrosstheentirerangeandincreasedlevel sion wasmodeledbyDeform(TM)finiteelementsoftware.Theinci- microstructure ontemperatureandstrainrate,axisymmetricextru- and 0.01-1/stodeterminethedependenceofflowstress,ductility FollowingtorsiontestsofMg-3Al-1Znintheranges180-450 cow 117911Russia Quebec H3G1M8Canada; Dept. ofMech.Eng.H-549,1455deMaisonneuveBlvd.W., Montreal, Myshlyaev Temperature andMicrostructure Extrusion ofAZ31:ModeledDistributionStress,StrainRate, 8:55 AM technology developmentformagnesiumextrusions. methods. We willalsodiscussmajorlimitationsandopportunitiesin and howthecostofextrusioncomparestothoseotherfabrication CRA willdiscussinthispapertheissuesrelatedtofabricationcosts, fabrication ofarangemagnesiumpartshastremendouspotential. nesium hasanHCPstructure.Thus,theapplicationofextrusionto magnesium millproductsisunlikelytobecost-effectivebecausemag- potential applicationsthatneedstrength.Conventionalrollingof is drivenbydiecastings,whichcannotbeusedinabroadersetof effective fabricationmethodsaredesigned.Today mostofthegrowth Magnesiumdemandwillgrowevenfasterifandwhenalternatecost- St. T-33,Boston,MA02116-5092USA 1 Katrak Alternative Ways toFabricateMagnesiumProducts 8:30 AM Madison, IL62060USA Session Chair: March 16,2000 Thursday AM Association, McLean,VA 22101USA 60439-4815 USA;ByronB.Clow, InternationalMagnesium John N.Hryn,Argonne National Laboratory, Argonne, IL Corporation ofAmerica,SaltLakeCity, UT84116 USA; Program Organizers: Committee, InternationalMagnesiumAssociation Sponsored by: Alloys andThixomolding Magnesium Technology 2000:Wrought Charles RiverAssociates,Inc.,JohnHancockTower, 200Clarendon 1 ; JagdishC.Agarwal 2 ; E.V. Konopleva : A. Ben-Artzy Light MetalsDivision,Reactive Lee T. Barnes,SpectruliteConsortium, 2 Ben-Gurion University, Beer-Sheva,Israel Location: OprylandConventionCenter Room: BayouC Howard I.Kaplan,Magnesium 2 Baikov InstituteofMetallurgy, RAS,Mos- 1 1 1 ; FrancisC.Brown ; A.Shtechman ; M.Sauerborn : H. J.McQueen 1 ; 1 ; N.Ben-Ari 1 ° 1 Concordia University, ; MichaelJ.Loreth C. Themaximumof : 2 1 ; Firoze E. ; M. 1 Rotem ° C 1 ; Alloys AZ31and80 Environmental EffectsontheHCFBehaviorofMagnesium 9:45 AM magnesium alloysinelevatedtemperaturerange. found tobedominatingplasticdeformationbehaviorofthewrought DRV (DynamicRecovery)andDRXrecrystallization)were due tothegrainrefinementcausedbypresenceofzirconium.The has nosensitivitytostrainratewithinthetestedtemperaturerange, found tobesensitivestrainrateinthemidtemperaturerange.ZK60 microstructure andmechanicalpropertieswasdetermined.AZ31 alloys. Theinfluenceofformingtemperatureandstrainrateonthe FLD (FormingLimitsDiagram)fortheAZ31andZk60magnesium range of0.1÷0.5andstrainrates0.001÷0.5(1/sec)wereusedtoplot cal samples,inthetemperaturerangeof290 needs betterthanthediecastMgalloys.Openhotforgingofcylindri- energy. Wrought magnesiumalloyshavethepotentialtoservethese characterized ingoodelongation,highyieldstrengthandimpact tural partshavetobeproducedfromenergyabsorptionmaterials, motive magnesiumpartsdemands.Magnesiumalloysusedforcarstruc- such asAZ91andAM50areoccupyingtheessentialpartofauto- implemented inthewesternworldandJapan.Castmagnesiumalloys cussed, considering componentrecycling,productivity, costsituation, for thebodystructureofvehicles. Possibleapplicationswillbedis- castings willcreatenewlight-weight designopportunitiesespecially extrusions areassessed.Thecombination ofMg-extrusionsanddie alloy applied,mechanicalproperties andproductioncostsoftheMg- advanced extrusionprocessformagnesium alloys.Dependingonthe complex, thinwalledsections.Focus willbeonthepresentationofan sium extrusiontechnologyhasreachedanadvancedstatustoproduce grated diecastcomponentsbecomevisible.Ontheotherhand,Magne- limitations regardingthemaximumdimensionsofhighlyinte- applying pressurediecastingmachinesupto50.000kNlockingforce, sate thehigherbasemetalcostcomparedwithaluminium.However, cial designopportunitiesandpropertiesofmagnesiumalloyscompen- into light-weightautomobilebodystructures.Inmanycases,thespe- Magnesiumpressurediecastingshavebeenintroducedsuccessfully Germany eter Brungs New DevelopmentsinMagnesiumProduction Technology 10:45 AM applicable tomagnesiumalloy. ties atall.Theresultssuggestthatfrictionstirweldingispotentially aluminum foilbetweenbattingfacesdonotdegradethejointproper- tion stirring.Itisfoundthatbothanodizingtreatmentandinsertionof posed offineandequiaxedgrainswhichhadrecrystallizedduringfric- latter. Thisisconsistentwith thefactthatbondlayerwascom- base material,thoughtheductilityremainedatonehalfofthat tion stirweldjointshowedmechanicalstrengthcomparabletothatof commercial magnesiumalloyAZ31sheethasbeeninvestigated.Fric- Theapplicabilityoffrictionstirweldingtohotrolledsheet Japan Dept. ofMatls.Sci.andEng.,Shibaura3-9,Minato-ku,Tokyo 1088548 Takeo Yokota of MagnesiumAlloyAZ31 Structure andMechanicalProperties ofFrictionStirWeld Joint 10:20 AM 10:10 AMBreak tion. mental effectsonfatiguecracknucleationandmicrocrackpropaga- peening androller-burnishing.Resultswillbeexplainedbyenviron- on specimenswhichhadbeenmechanicallysurfacetreatedbyshot aqueous 3.5%NaClsolution.Inaddition,afewtestswereperformed cies ofabout100Hz.Tests weredoneinvacuum,ambientairandan fully reversed(R=-1)axialloadingusingaresonancetesteratfrequen- performed onelectrolyticallypolishedhour-glassshapedspecimensin 31 andAZ80wasstudiedinvariousenvironments.HCFtestswere ThefatigueperformanceoftwowidelyusedmagnesiumalloysAZ Metallu., P.O. Box101344,Cottbus03013Germany nical UniversityofBrandenburg atCottbus,Matls.Tech. andPhys. 1 ; 1 ; Tadahiro Ueki 1 Honsel AG,Fritz-Honsel-Strasse,Merschede59872 : Matthias Hilpert : Takeshi Nagasawa 1 ; 1 Shibaura InstituteofTechnology, 1 ; LotharWagner ° C÷420 1 ; MasahisaOtsuka ° C, straininthe 1 ; : 1 Tech- Di- 1 ;

THURSDAY AM 192 Tosoh 1 ; 1 /Ar flow ratio on -based dielectrics, 2 2 . Among many barrier Hao Zhang 2 : US Competitors, LLC, 561 1 ; 1 Yellapu V. Murty, Carpenter Technol- Carpenter Murty, V. Yellapu Room: Lincoln C Location: Opryland Convention Center Yellapu V. Murty, Carpenter Technology Murty, V. Yellapu Electronic, Magnetic & Photonic Materials Magnetic & Photonic Electronic, John L. MacWilliams : structures, and has attracted considerable attention. In this study, 2 causing degradation and failure in IC devices. Therefore, the applica- causing degradation and failure in IC devices. diffusion barrier which tion of Cu interconnect requires an effective can prevent Cu from diffusing into Si and SiO Upper Pike Creek Rd., Newark, DE 19711 USA The talk will summarize significant industry and technology trends in fiber optics. Photonics is now a multi billion-dollar thread woven into the $1.75 trillion information technology market. The market segments, industry dynamics, and global competition will be presented The associated component technologies vital to this as an overview. highly sophisticated markets will be described. 8:30 AM and Sputter Deposition of Ta/TaN Sputtering Target Tantalum Diffusion Barriers For Cu Interconnect were sputter deposited from thickness films with different and TaN Ta was evalu- targets The performance of the Ta targets. high-purity Ta ated. The effects of process parameters such as N mechanical stresses and film properties such as electrical resistivity, barriers and TaN film uniformity were studied. The properties of Ta are strongly dependent on the sputtering process. In addition, the Ta film thickness distribution across 200 mm Si wafer was simulated by using SIMBADTM package (SIMBADTM is a trademark of Alberta Microelectronic Center), and compared to the experimental results. films and TaN The phases and the crystallographic texture of the Ta were studied by using X-ray diffraction and pole figure analysis. 9:00 AM Keynote for the New Photonics: Strategic Technology Mainstreaming Millennium Materials Issues in Microelectronics: Issues Materials Thermal: Electrical and Optical, Issues Packaging by: Sponsored and Interconnection Electronic Packaging Division, Committee Materials Organizers: Program and Development, Reading, PA ogy Corporation, Research Godavarti, Motorola, Austin, TX 19612-4662 USA; Prasad Jin, Bell Laboratories, Lucent Tech- 78721 USA; Sung-Ho J. NJ 07974 USA; Sung Kang, IBM, T. nologies, Murray Hill, NY 10598 Heights, Yorktown Research Center, Watson US Competitors, LLC., Newark, DE USA; John Macwilliams, Fujitsu Computer Packing 19711 USA; Mark McCormack, CA 95134 USA; Martin Weiser, San Jose, Technologies, Materials, Plated and Discrete AlliedSignal Electronic 99216 USA WA Products, Spokane, Thursday AM March 16, 2000 Session Chairs: 19612-4662; Reading, PA Corporation, Rsch. & Dev., Appl. Matls. and Sungho Jin, Lucent Technologies, Metallu. Grp., Murray Hill, NJ 07974 USA OH 43123 USA SMD, Inc., 3600 Gantz Rd., Grove City, material to replace Copper is considered as a new interconnect because of its low aluminum alloys in sub-0.25 micron IC devices stress migration resistance. excellent electromigration and resistivity, SiO However, Cu can readily diffuse into Si and are reported to have excellent and TaN materials have been studied, Ta Sputtering is an effec- diffusion barrier properties between Cu and Si. in the Cu/barrier/Si or Cu/barrier/ and TaN tive method to deposit Ta SiO ; ; ; 2 1 2 ; H. Kubo 2 T. Tsukeda T. : Tohoku Univer- Tohoku 2 ; Eric A. Nyberg 1 ; K. Maruyama 2 Thixomat, Inc., 620 Tech. Dr., Thixomat, Inc., 620 Tech. 1 ; 2 ; J. Koike 2 Pacific Northwest National Laboratory, 2 ; Raymond F. Decker ; Raymond F. 1 ; M. Suzuki 1 ; Stan G. Pitman 2 ; K. Saito 1 RobertCarnahan D. : The Japan Steel Works Limited, 1-6-1 Funakoshi-Minami, Aki-ku, Funakoshi-Minami, Limited, 1-6-1 Steel Works The Japan Ann Arbor, MI 48108 USA; Ann Arbor, USA 99352 Richland, WA Box 999, Matls. Res., Battelle Blvd., P.O. known for its high tem- In this study magnesium alloy ZAC8506, the semi-solid form- perature creep resistance, has been formed using alloys have not proven ing process known as Thixomolding®. The ZAC because of their rela- to be amenable to processes such as die-casting die-casting alloys. tively poor castability as compared to standard and molding param- However, it was shown that with proper die design Moldability was eters, Thixomolding® of the ZAC alloy is possible. an automotive electrical evaluated by evaluating the formability of cover box was cover box and a spiral fluidity test. The electrical mechanical properties. evaluated for porosity and room temperature is below that of typical The results indicate that the level of porosity a joint program with the die-cast components. This work is part of Alliance for Trans- Pacific Northwest National Laboratory (Northwest Pro- for Next Generation Vehicle portation Technology-Partnership temperature applica- gram) and Thixomat, Inc. to evaluate the high to automotive application of Thixomolded magnesium components of the ZAC8506 alloy, tions. Due to the promising formability results Thixomolded AZ91D a comparison of the creep performance between and ZAC8506 was conducted using an instrumented bolt load retention In addition, die-cast AZ91D and die-cast component assembly. ZAC8506 properties were compared. The results of both the bolt load retention tests and the comparison with the die-cast materials will be reported. sity, Japan sity, in- new process in which the metallic slurry is Thixomolding is a at semi-solid temperature to form near net- jected into a die cavity solid feed stock in one step. The relationship shape products from the of composition and the mechanical properties between the chemical alloys was investigated. The heat-resistant Mg-6mass%Al-04mass%Ca such as barrel temperature was also studied. effect of process condition of Ca was effective to improve the yield It was found that the addition resistance at elevated temperatures. The ductil- strength and the creep Ca content. The microstructure of speci- ity decreases with increasing and TEM showed a fine hypoeutectic structure mens observed by SEM Mg solid solution and phase (Mg17Al12) net- consisting of granular Ca. The morphology of these networks var- works incorporated with ies depending on Ca content. AM 11:35 Components Developments of Semi-Solid Molded Magnesium Proper- Creep High Temperature Alloys with Improved from ties Hiroshima City, Hiroshima-pref. 736-8602 Japan; 736-8602 Japan; Hiroshima-pref. City, Hiroshima 1 mechanical properties and joining technologies like fusion welding and fusion welding like technologies and joining properties mechanical stir welding. friction AM 11:10 of Heat-Resistant Properties and Microstructure Mechanical Process Alloys Formed by Thixomolding Mg-Al-Ca A. Maehara Russell H. Jones

THURSDAY AM 193 white LED,willalsobeincluded. will alsobediscussed.Demonstrations ofInGaNLEDs,includingthe tance willbediscussedforcontacts toLEDs.Novelcontactstructures amples. Thetradeoffbetweenoptical transmissivityandcontactresis- dride formingmetals.We willdiscuss theabovestrategieswithex- Transparent holeinjectingoxides;3.NitrideFormingmetals;4.Hy- may beformedin4differentways:1.Highworkfunctionmetals; 2. the bandgapandelectronaffinityofGaN.OhmicContactstop-GaN type GaNandthelackofmetalswithhighworkfunctionscompared to because ofthedifficultyinachievinghighholeconcentrations p- devices. Lowcontactresistancestop-typeGaNaredifficultobtain 10^- 4ohm.cm^2.Thesevaluesaretoohighforperformance specific contactresistancesareintherangefrom2.1×10^2to9.6 × contacts havebeenappliedtop-typeGaN,andallofthereported ever, ohmiccontactstop-typeGaNarestillachallenge.Various metal contact ton-typeGaNhasbeendemonstratedusingTi/Al/Ni/Au.How- influenced bythecontactresistance.Averylow-resistanceohmic performance ofthesedevicessuchasoperatingvoltageisstrongly Laser Diodes.OhmiccontactstoGaNareveryimportantbecausethe high brightnessblue/cyanandgreenlightemittingdiodesviolet optoelectronic devicesbecauseofthesuccessincommercialization ThegroupIIInitrides,especiallyGaN,areattractivematerialsfor 94720 USA sity ofCalifornia,Matls.Sci.andEng.,161MCoryHall,Berkeley, CA Ohmic Contactstop-GaN 10:15 AM conductivity intheelementalheatsinkmaterials. posite oralloyingapproaches,whilepreservingmuchofthethermal heat sinkmaterialswithCTEsclosetothatofSiusingeitheracom- highly desirabletominimizetheCTEmismatchbydevelopingnew ously degradingthedevicereliabilityandlifetime.Therefore,itis can leadtostressesthattriggercomplexfailuremechanismsseri- CTE mismatchbetweenthevariousmaterialsinanelectronicpackage have amuchhighercoefficientofthermalexpansion(CTE)thanSi. The heatsinkmaterialscommonlyusedtodaysuchasCuandAlalloys tures, aswelltheirpotentialdeviceapplicationswillbediscussed. examples ofCTEcontrolinelectronicmaterialsandcompositestruc- magnetic transitionorphasenearroomtemperature.Some very small,large,near-zero,ornegativeCTEvaluesbyutilizing of modifyingthethermalexpansionbehavior,e.g.,soastoobtain intrinsic propertyofmaterials.However,therearesomenovelways performance andreliability. TheCTEisgenerallyconsideredtobean various componentmaterialsisanimportantissueintermsofdevice behavior ofmaterials,especiallythemismatchinCTEamong Inmicroelectronicdevicesandassemblies,thethermalexpansion Ave., MurrayHill,NJ07974USA 1 Microelectronic Applications Modification ofThermalExpansionBehaviorMaterialsfor 9:50 AM NAL applications. tor industrysince1997.EmergenceofNALapplications.Future alpha levelsofLowAlphaLead(LAL)purchasedbythesemiconduc- tion, certification,physicalformsoftheendproduct.Chart industry specifications,eliminatingsourcesofradioactivecontamina- concern tothesemiconductorindustry;refiningissues: tive impuritytestingandresults(chart);non-radioactiveimpuritiesof alpha particleemissiontestingandresults;74elementnon-radioac- pearance; cuttingsamplesfromingotswithoutalphacontamination; issues. Radioactivedecayinantiquitylead;ingotsize/weightandap- lead clusters,lackofdispersionfactors,surveyedquantities,recovery of antiquitylead;RomanapplicationsresultinginSeaRecoveryLtd with findingintactclusters;Europeancountrypoliciesontheexport large volumesoflead;historicdispersionfactors;problemsassociated ApplicationsforleadintheRomanEmpire;applicationsclustering 1 Antiquity Lead,SourceofNoAlphaLead(NAL) 9:25 AM Sea RecoveryLimited Bell LaboratoryLucentTechnologies, Rm.1A-123,600Mountain : Sujit Pillai : Sungho Jin 1 ; EickeR.Weber 1 ; HareeshMavoori : Rick Jensen 1 ; 1 Univer- 1 1 ; ; examined fortheirrespectiveadvantagesandlimitations. tigue), residualstressesandtribologicalcharacteristicsarealsobriefly dent, thermo-mechanicalproperties(elastic,plastic,fractureandfa- techniques forthequantitativedeterminationofgeometry-depen- length-scales andsize-dependenceofmaterialproperties.Theexisting volume structuresarepresentedanddiscussedwithinthecontextof and deformationinawidevarietyofapplicationsinvolvingsmall- response ofMEMSinaunifiedfashion.Theoriesforpredictingstresses the objectiveofaddressinguncoupledandcoupledmechanical piezoelectric ormagnetostrictive).Thisframeworkisdevelopedwith or fullyconstrained),andcouplingcharacteristics(puremechanical, D or3-D),structuralenvironment(unconstrained,partiallyconstrained classification ofminiaturestructuresbasedontheirgeometry(1-D,2- duced andservice-inducedstresses.Inthiswork,weproposeanovel ing withtheprediction,measurementandcontrolofprocessing-in- eral materialsandmechanicsissuesinMEMS,particularlythosedeal- ity ofMEMSdevicesrequiresacomprehensiveunderstandingsev- electro-mechanical, thermal,optical,fluidicormagneticfunctional- vices. Itisincreasinglybecomingevidentthattheoptimizationof limit thedesign,fabricationandoperationalreliabilityofthesede- ing, anddevelopingsolutionsto,themulti-disciplinaryproblemsthat logical impact,therealizationofwhichdependscriticallyonidentify- rapidly growingfieldwithalargepotentialforfar-reachingtechno- (MEMS), andMEMS-basedfunctionaldevicescollectivelyrepresenta Small-volumestructures,Micro-Electro-MechanicalSystems Cambridge, MA02139USA mer-Metal Interfaces Roles ofSelf-AssembledMonolayersinSlowCrackingPoly- 10:40 AM Suresh Electro-Mechanical Systems(MEMS) Stresses andDeformationinMiniatureStructuresMicro- 11:05 AM the changesincrackgrowthmechanisms. and unmodifiedinterfaces.Thesedifferencesarediscussedintermsof short-term adhesionandinlong-termdurabilitybetweenthemodified that oftheunmodifiedinterface.Strikingdifferenceswereobservedin mined usinginterface-fracturemechanicstechniques,andcomparedto fied polymer-metalinterfacestostress-corrosioncrackingwasdeter- introduced atthepolymer-metalinterface.Theresistanceofmodi- were synthesizedandmonolayersofthepolymers Al systems.Self-assemblingphosphonicacidswithvariousendgroups explored toinhibitinterfacialstresscorrosioninepoxy/Cuandepoxy/ ment. Inthisstudy, theuseofself-assembledpolymermonolayerswas ally underthecombinedactionofinternal/externalstressandenviron- tronic devices.Theadhesionofpolymertometalcandegradegradu- Polymer-metalinterfacesarebuiltintoawiderangeofmicroelec- Green St.,Urbana,IL61801USA Illinois atUrbana-Champaign,Dept.ofMatls.Sci.andEng.,1304W. 1 ; 1 MIT, Matls.Sci.andEng.,Rm.8-13977MassachusettsAve., : Tianbao Du 1 ; JianKuShang : T. A.Venkatesh 1 ; 1 University of 1 ; Subra

THURSDAY AM 194 ; ; ; ; 1 1 1 1 C. ° Daido ; Kei- 2 4 : Hisao University 1 ; 2 Javaid I. Qazi : ; Daisuke Kuroda 1 ; David E. Alman 1 ; Ryosuke Isohama 1 ; Shigeki Katsura Tekeuchikatan Limited, Tekeuchikatan 3 3 Toyohashi University of Tech- Toyohashi 1 ; 2 ; William M. Mullins 1 Yamahachi Dental MFG Company, Dental Yamahachi ; Shinya Yoshitani 4 2 Aichi-Gakuin University, Dept. of Den- Dept. University, Aichi-Gakuin 2 Mitsuo Niinomi Stephen J. Gerdemann : ; Tsutomu Takeuchi ; Tsutomu 1 : ; Akihiro Suzuki 1 ; Francis H. Froes 1 ; Jiro Hasegawa 1 Mitsuo Niinomi ; 2 Albany Research Center-DOE, Therm. Treat. Tech., 1450 Queen Tech., Albany Research Center-DOE, Therm. Treat. Toyohashi University of Technology, Dept. of Product. Sys. Eng., Dept. of Product. Sys. of Technology, University Toyohashi US Army Research Office, AMSRL-RO-PM, P.O. Box 12211, Re- Box 12211, P.O. AMSRL-RO-PM, US Army Research Office, of Idaho, IMAP, Mines Bldg. Rm. 321, Moscow, ID 83844-3026 USA; ID Mines Bldg. Rm. 321, Moscow, of Idaho, IMAP, Oleg N. Senkov 1 OR 97321 USA Albany, S.W., Ave. The sintering behavior of titanium powder that was produced by a novel reduction process was characterized. Green specimens were die pressed into cylindrical compacts and vacuum sintered. The influence final sintering temperature and sintering time on the of green density, nology, Dept. of Product. Sys. Eng., Toyohashi 441-8580 Japan; Dept. of Product. Sys. Eng., Toyohashi nology, 455-0811 Japan Steel Company Limited, R&D Lab., Nagoya and de-hy- Thermomechanical processing, that is, hydrogenation to improve the balance drogenation process was investigated in order of Ti-6Al-7Nb for of strength and ductility of investment castings castings conducted with dental applications. Elongation of Ti-6Al-7Nb smaller than expected conventional thermochemical processing is The good balance of value, over 10%, although strength is enough. proper heat-treat- strength and ductility can be achieved by adopting processing. The ments after de-hydrogenation in the thermochemical dehydrogenation is a microstructure of the heat-treated alloy after However, the micro- little coarser than that of the un-treated one. is a little structure of the heat-treated alloy after de-hydrogenation more spherical than that of the un-treated one. 10:25 AM Alloys in Ti-6Al-4V-xH Phase Transformations 2 search Triangle Park, NC 27709-2211 USA Ti-6Al-4V alloy samples were alloyed with 10, 20 and 27 at.% hydrogen by holding the samples in a hydrogen atmosphere at 780 The different hydrogen alloying was achieved by varying the hydrogen partial pressure in the chamber during hydrogenation. Phases and temperatures of phase transformations in the hydrogenated samples were determined by X-ray and microstructural analyses. TTT diagrams for decomposition of metastable beta and martensitic phases were also determined using similar approach. Using the results obtained, conditions of heat treatment of the hydrogenated samples were optimized leading to a refined grain structure and improved mechanical properties after dehydrogenation. 10:50 AM Sintering Behavior of a Titanium Powder Produced by a Novel Continuous Process was also tested. The finer grainsize obtained with vacuum die casting vacuum die with obtained finer grainsize tested. The was also tensile properties. on the positive effect had a 9:20 AM Alloy Titanium Beta-Type Castings of Dental Investment ichi Fukunaga 1 441-8580 Japan; Toyohashi Japan; Sci., Nagoya 464-8650 tal Matls. 441-8132 Japan; Toyohashi Gamagori 443-0105 Japan casting processes of newly developed beta-type Dental investment of non-toxic elements, Ti-29Nb-13Ta-4.6Zr titanium alloy composed in- were investigated. The effects of for orthopedic instrumentations of the surface reaction and tensile properties vestment materials on examined in this in particular, castings were, Ti-29Nb-13Ta-4.6Zr is greater when The mold reaction of Ti-29Nb-13Ta-4.6Zr study. system materials is used for investment mate- alumina with phosphate with non-phosphate system one is used. The rials than when magnesia is greater on the surface of Ti-29Nb-13Ta-4.6Zr mold reaction observed biomedical pure titanium and Ti-6Al-4V. than that of conventional casting is smaller than that strength of Ti-29Nb-13Ta-4.6Zr Tensile castings is while elongation of Ti-29Nb-13Ta-4.6Zr of Ti-6Al-4V greater than that of Ti-6Al-4V castings. 9:45 AM Break 10:00 AM Castings for Bio- Thermochemical Processing of Ti-6Al-7Nb medical Applications Akahori Toshikazu Fukui : Air 1 ; 1 ; S. Lee Semiatin 1 was used throughout. A combination of  James A. Hall, Oremet-Wah Chang, James A. Hall, Oremet-Wah Pamela A. Kobryn Howmet Research Corporation, Adv. Tech., Howmet Research Corporation, Adv. Room: Knoxville B Convention Center Location: Opryland 1 : ; 1 Boyd Mueller, Howmet Corporation, Boyd Mueller, Materials Processing and Manufacturing Materials 1500 S. Warner St., Whitehall, MI 49461 USA 1500 S. Warner Ti-15V-3Cr-3Al-3Sn (Ti-15-3) is a metastable beta titanium alloy that is age hardenable. Minor variations in both composition and aging temperature cause a dramatic difference in the morphology and amount of alpha precipitation during the solution and age cycles. This in turn effects the tensile properties, which can range from very high strength This study inves- to low strength and high ductility. and low ductility, tigated three compositional variants of Ti-15-3: an alpha rich composition, a nominal composition, and a beta rich composition. All three were within the typical range of acceptable compositions for Ti-15-3. After hot isostatic pressing and solutioning, a number of single, double, results will be and triple step aging cycles were investigated. Tensile discussed along with recommendations for optimizing the composition and aging temperature to obtain an alloy with high strength while The majority of this work was con- maintaining adequate ductility. ducted using investment casting, however, vacuum die cast material 8:30 AM on Solidification, Micro- The Effect of Interface Heat Transfer During Permanent Mold Evolution, and Mold Wear structure Casting of Ti-6Al-4V March 16, 2000 Session Chairs: RMI Corpora- USA; Kuang Oscar Yu, Whitehall, MI 49461 tion, R&D, Niles, OH 44446-0269 USA Thursday AM Sponsored by: Sponsored Committee, Division, Titanium Materials Division, Structural Forming Committee Shaping and Organizers: Program of H. (Sam) Froes, University 97321 USA; F. OR Albany, ID 83844-3026 Bldg. #321, Moscow, Idaho, IMAP-Mines USA; Kuang Oscar Johnson Matthey USA; Isaac Weiss, Niles, OH 44446-0269 USA RMI Corporation, R&D, Yu, Process Synthesis and Modeling for the for Modeling and Synthesis Process & of Titanium & Processing Production Session V Its Alloys: Force Research Laboratory, Met., Cer., and Nondestruct. Eval. Div., and Nondestruct. Met., Cer., Force Research Laboratory, St., Ste. 1, Wright-Patterson AFRL/MLLM Bldg. 655, 2230 Tenth AFB, OH 45433-7817 USA developed for predict- Computer simulation capabilities have been evolution, and mold ing characteristics of solidification, microstructure The solidification wear for permanent mold casting of Ti-6Al-4V. modeling package ProCAST Donald R. Clemens physical and numerical experiments was used to determine interface physical and numerical experiments was used using the chosen model- heat transfer coefficients and the validity of various casting geom- ing approaches and input parameters to simulate were conducted to obtain etries. Laboratory and in-plant casting trials to simulation results casting data. Thermocouple data were compared for “shrink off” and to determine interface heat transfer coefficients thermocouple “shrink on” casting geometries. Both a conventional mold temperature signa- technique and a novel microstructure-based mold temperatures for ture analysis technique were used to determine used to predict micro- model validation. The validated models were state grain growth. The structure via solidification mapping and solid importance of properly accounting for the casting-mold interface contact condition was stressed throughout. 8:55 AM and Aging Tempera- The Effects of Compositional Variation of Cast Ti-15V-3Cr-3Al-3Sn Properties on the Tensile ture

THURSDAY AM 195 repository. Besides actinides,themetallicwaste formconsistsofstain- into ametallicwaste formthatisdestinedfordisposal inageologic extract usableuranium.Someofthe residualactinidesareincorporated Laboratory totreatspentnuclear fuels.Thisprocessisemployedto electrometallurgical processbeing developedbyArgonneNational SmallamountsofU,Pu, andNpareleftoverfroman Laboratory, 9700S.CassAve., Argonne, IL60439-4803USA P.O. Box2528,Idaho Falls,ID83403-2528USA; P. Abraham Nuclear Waste Forms Characterization ofActinide-ContainingMetallicHigh-Level 9:00 AM 109-ENG-38. Sciences, DivisionofChemicalSciencesundercontractnumberW-31- formed undertheauspicesofU.S.DOEOfficeBasicEnergy and theiruniquechemicalpropertieswillbeemphasized.Work per- ment restorationwillbepresented.Thebroadutilityofthesereagents phosphorus compoundsinactinideproduction,disposal,andenviron- actinide transmutation.Anoverviewoftheuniqueroleorgano- reagents forlanthanide-trivalentactinideseparationsnecessary for thiophosphinic acidshavebeenidentifiedaspotentiallyimportant have beendevelopedoverthepast15-20years.Recently, phorus extractants,aqueouscomplexants,andionexchangeresins to theneedforcompleteactiniderecoveryinprocessing,organophos- tion processesbasedonneworganophosphorusreagents.Inresponse elements tothedevelopmentofseparationandenvironmentrestora- phate andPUREXprocessesforlarge-scaleproductionoftransuranic phate mineralphasesthroughtheapplicationofbismuthphos- all aspectsfromthestabilityofnaturallyoccurringactinidesinphos- fuel. Actinideinteractionswithphosphorus-containingspeciesimpact particularly inthehydrometallurgicalprocessingofirradiatednuclear reagents havefiguredprominentlyinnuclearscienceandtechnology, Interactionsofactinideionswithphosphateandorganophosphate IL 60439-4831USA 1 Tools forProduction, CleanupandDisposal Organophosphorus ReagentsinActinideSeparations:Unique 8:30 AM and Matls.Eng.,Tuscaloosa,AL335487USA USA; RamanaG.Reddy, UniversityofAlabama,Metallu. Mines, KrollInstit.ofExtract.Metallu.,Golden,CO80401 Session Chairs: March 16,2000 Thursday AM Golden, CO80401-1887USA School ofMines,KrollInstituteforExtractiveMetals, ing, Reno,NV89557-0136USA;BrajendraMishra,Colorado Nevada-Reno, DepartmentofChemicalandMetalEngineer- Program Organizers: Committee Sponsored by: Actinides I:Processing Technology andApplicationsIV: Rare EarthsandActinides;Science able spongefinepowdersandcastwroughttitanium. pared tothepropertiesofmaterialproducedfromcommerciallyavail- temperature tensilepropertiesweremeasured.Theresultscom- dated usingthedeterminedoptimalsinteringconditions,androom were concluded,near-net-shapetensilebarspressedandconsoli- density andmicrostructurewasevaluated.Oncetheseexperiments Argonne NationalLaboratory, Chem.Div., 9700S.CassAve., Argonne, 2 ; 1 Argonne NationalLaboratory-West, NuclearTech., Light MetalsDivision,Reactive Brajendra Mishra,ColoradoSchoolof : Location: OprylandConventionCenter Room: LincolnE Dennis D.Keiser Renato G.Bautista,Universityof 1 ; WhartonSinkler : Kenneth L.Nash 2 Argonne National 1 ; Daniel 1 ; Residue Processing Vitrified MagnesiaDissolutionanditsImpactonPlutonium 9:30 AM Comments willbemadeastowhythisactinidebehaviorisobserved. the actinidesfavoringoneLavesphasepolytypeoverothers. segregate intospecificregionsofthisphase,andisprobablydueto phases, viz.anFe2ZrLavesintermetallic.Theactinidesarefoundto actinides arefoundtocongregateintooneofthetwomajoralloy treatment. Focusisgiventotheactinidebehaviorinalloys.The from actualirradiatedmaterialthatisresidualelectrometallurgical paper discussesthemicrostructuraldevelopmentinalloysgenerated Pd). Thebaselinealloycompositionisstainlesssteel-15wt.%Zr. This less steel,zirconium,andmetalsnobletotheprocess(e.g.,Tc, Ru,and cibles forhydrochloricacidneutralization. duction equipmentandpresentsourresultsinusingthemagnesiacru- presentation discussesourexperienceindefiningappropriatesizere- and usingitasareagentinroutineplutoniumresidueprocessing.This since thiswouldinvolvetakingastreamdestinedfortransuranicwaste pyrochemical cruciblesastheacidneutralizationagentisattractive ity. From awasteminimizationstandpoint,theuseofspentmagnesia chloric acidmustbeneutralizedandfilteredpriortoexitingthefacil- ibility problemswithexistingdisposallines.Consequently, allhydro- cannot directlydisposeofacidicwastesolutionsbecausecompat- AqueouschlorideoperationsattheLosAlamosPlutoniumFacility Chem., P.O. Box1663MS-E511, LosAlamos,NM87545USA National Laboratory, NuclearMatls.Tech. Div./Actinide Process : Keith W. Fife 1 ; JenniferL.Alwin 1 ; 1 Los Alamos

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