DOCSLIB.ORG

A Study of Self-Glazing Titanium Carbide Base

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
A Study of Self-Glazing Titanium Carbide Base A STUDY OF SELF-GLAZING TITANIUM CARBIDE BASE CERMETS Dissertation Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Robert Franklin Stoops, B.S., M.S. The Ohio State University 1951 Approved by Adviser ACKNOWLEDGMENTS The author wishes to thank Mr. Earle T. Montgomery, Senior Research Engineer, Mr. Thomas S. Shevlin, Research Engineer, and Mr. Harold Greenhouse of the staff of the Ohio State University Research Foundation Project 441 for their guidance, aid, and advice and for the design and construction of the equipment used in this investigation. He also wishes to express his appreciation to his adviser, Dr. G. A. Bole, Director of Ceramic Research, Engineering Experiment Station, The Ohio State University, under whose general supervision this work was accomplished. The work described herein was supported, in part, by the Materials Laboratory, Research Division of Wright Air Development Center through a contract between the Air Research and Development Command and The Ohio State University Research Foundation. ii 892567 The University assumes no responsibility for the accuracy or the correctness of any of the statements or opinions advanced in this dissertation. iii TABLE OF CONTENTS Page INTRODUCTION ............................................ 1 SURVET OF LITERATURE.................................... 3 Highly-rRefractory Materials......................... 3 Auxiliary Me t a l s .................................. 7 Cermets.............................................. 17 Sintering In the Presence of a Liquid Phase............20 MODE OF INVESTIGATION.................................... 23 MATERIALS AND EQUIPMENT.................................. 25 Materials............................................ 25 Equipment...................... 30 PROCEDURE................................................ 39 Tests for Physical Properties......................... 39 Titanium Carbide + Silicon Carbide Boron Carbide Base Compositions.................. 41 Titanium Carbide + Titanium Diboride + Silicon Base Compositions....................... 45 RESULTS AND DISCUSSION .................................. 49 Titanium Carbide + Silicon Carbide + Boron Carbide Base Compositions............... 49 Titanium Carbide + Titanium Diboride + Silicon Base Compositions ......................... 67 GENERAL S U M M A R Y .......................................... 97 iv TABLE OF CONTENTS Page CONCLUSIONS............................................ 99 BIBLIOGRAPHY ............................................ 101 AUTOBIOGRAPHY .......................................... 105 v ILLUSTRATIONS Figures Page 1. Ratios of Specific Volumes of Oxides of Metals To Those of the Metals............................ .11 2. Phase Diagram of the Cobalt-Silicon System............ 16 3. Molybdenum-Resistor Furnace ........................... 32 4. Section Through Center of Molybdenum-Resistor Furnace . 33 5. High Frequency Induction Furnace..................... 34 6. Cross Section of High Frequency Induction Furnace.... 35 7. Globar Tube Furnace................................. 37 8. Hot Modulus of Rupture Furnace. .................. 38 9. 721 R + Co Sintered at 3875°F. (Photomicrograph).......53 10. 721 R Jr NiAl Sintered at 3375°F. (Photomicrograph). 54 11. 721 R Sintered at 4100°F. (Photomicrograph).......... 58 12. 721 Sintered at 4100°F. (Photomicrograph) ............. 59 13. Effect of Sintering Temperature on Porosity of TiC + SiC + B.C Base Cermets...................... 63 4 14. Effect of Sintering Temperature on Porosity of TiC + TiB2 Si Base Cermets........................ 72 15. Composition III R Co Sintered at 2800°F. (Photomicrograph) ................................ 74 16. Long Time Oxidation in Open Air at 2000°F................ 77 17. Effect of Changes in Composition on Oxidation of TiC + Ti®2 + Si + Co Cermets...................... 83 vi ILLUSTRATIONS Figures Page IS. Effect of Sintering Temperature on Transverse Strength of TiC + T±B^ 4- Si 4- Co Cermets.......... 87 19. Graphite Boats Containing Fired B a r s ............... 89 20. Ill R B + Co Sintered at 2800°F. (Photomicrograph) .... 91 21. Change of Modulus of Rupture of Composition III R B +• Co with Temperature......................94 Tables I. Data on Highly-Refractory Materials. .............26 II. Particle Sizes of Milled Carbides.................... 28 III. Data on Raw Materials........... 29 IV. Compositions Studied........... 46 V. Results of Wetting Tests .............................. 52 VI. Results of Sintering Tests on 721 Base Composition .... 56 VII. Porosities of Sintered Cermet Pellets Based on 721 .... 62 VIII. Effect of Sintering Temperature on Properties of 721 R 4- C o ....................................... 65 IX. Porosities of Sintered Cermet Pellets Based on TiC 4- TiB2 + Si................................... 69 X. Results of Oxidation Tests . ......................... 75 XI. Values for the Parameter "k" from Long Time Oxidation Tests................................... 76 vii ILLUSTRATIONS Tables Page XII. Effect of Sintering Temperature on Properties of TiC ♦ TiB£ 4- Si + Co Cermets.........................86 XIII. Change of Modulus of Rupture of Composition III R B + Co with temperature.......................93 XIV. Results of Thermal Shock Tests......................... 95 viii INTRODUCTION The efficiency of gas turbines would be greatly increased if they could be operated at temperatures above those currently being used. The metallic alloys from which the turbine blades are made have a relatively short service life at an operating temperature of 1800°F. At present, a material is being sought which will have a useful service life at a temperature between 1800°F. and 2400°F. Such a material should have a high tensile strength to density ratio in this temperature range because the stresses developed in turbine rotor blades are caused mainly by centrifugal forces. The material should also be resistant to oxidation and to thermal and mechanical shock. Much research has been directed toward combining highly-refrac- tory ceramic materials with metals in order to obtain a material that possesses both the high strength to density ratio at elevated temper­ atures of ceramics and the thermal and mechanical shock resistance of metals. Some of these combinations, called "cermets", which show promise utilize titanium carbide as the ceramic phase. However, these cermets lack the necessary oxidation resistance, since their chief constituent, titanium carbide, oxidizes readily at elevated temperatures. If these compositions are to be used successfully in turbine blades, they must be coated with an oxidation resistant material or other constituents must be added to the cermet composi­ tions which will render them oxidation resistant. In an investigation of the titanium carbide - silicon carbide - boron carbide system, Accountius^ found several compositions rich in titanium carbide which had excellent oxidation resistance. These materials were oxidation resistant as a result of the formation of a glass on their surfaces when they were exposed to oxidizing condi­ tions. The purpose of this investigation is to develop a self-glaz­ ing cermet by using one of these oxidation resistant compositions as a base material. SURVEY OF LITERATURE HIGHLY-REFRACTORY CERAMIC MATERIALS Schwarzkopf^ has stated that materials will have high strength at elevated temperatures if the individual crystals have high strength interatomic bonds and if the various crystals have high boundary strength. Highly-refractory materials possess relatively strong inter­ atomic bonds since the energy requirements for melting are related to the atom-to-atom bond strength. He suggests that the powder metal­ lurgy technique could be utilized to control boundary strength. Titanium Carbide Titanium carbide is one of the. most refractory materials known. It has a melting temperature of 5684°F. Gangler, Robards, and 17 McNutt ', who investigated the physical properties at elevated temper­ atures of hot-pressed TiC, MgO, ZrC, B^C, 85$ SiC 15$ B^C, ZrOg, and stabilized Zr02, found that titanium carbide had the best resistance to thermal shock and was generally the most promising of the composi­ tions tested. It had a short-time tensile strength of 15,850 p.s.i. at 1800°F. and 9400 p.s.i. at 2200°F. Deutsch, Repko, and Lidman^ concluded from their investigation that titanium carbide base cermets may eventually be used as gas turbine blade materials in the temper­ ature range of 1600°F. to 2400°F. 33 Nowotny and Glenk asserted that titanium carbide tends to have a lattice which is deficient in carbon. The best titanium carbide -3- that they could obtain had only 19*36# carbon, whereas the theoret­ ical value is 20.0#. Franssen"^ has stated that, as a rule, com­ mercial titanium carbides do not contain more than 18# of fixed carbon; but, in order to obtain a fixed carbon content of 18#, an excess of carbon must be used. This free carbon remains in the carbide as graphite. Skaupy^ also thinks that commercial titanium carbides contain less than theoretical carbon, but that they contain an oxide of titanium in solid solution in the titanium carbide. This oxide of titanium comes from the process in which rutile and carbon are combined to make titanium carbide. Such a carbide containing oxygen will not produce dense sintered compacts. Skaupy believes that the carbide made by Kennametal, Inc., is superior to other commercial titanium carbides because
Load more

Recommended publications
  • UNITE-D STATESJPATBNT Omen .V
    .' Patented Sept. 11,1934 1,973,428 UNITE-D STATESJPATBNT omen .v ’ 1,973,428 ; CEMEN'I'ED man ommn'm'raamn Gregory J. Comstock, Edgcwoorl, Pa. assignor'to ~: ' ' ' , Firth-Sterling Steel CompanmMcKeeeport, 2a., , a corporation of Pennsylvania Y . ‘ ' ' No Drawing. Application November 8,‘ 1932, Serial No. 641,762 r .' 3 Claims. (ems-1‘) cold-press, method or the hot-ypress' method. In , . This invention relates generally to hard- ce-f the cold-press method thefmixtureis compacted " mented carbide materials made by a cementing into 'a billet under relatively ‘high'pressure, for -' ‘ or sintering process, and more ‘particularly to example 10,000#/sq.~ in.v and is then preferably such materials containing tungsten carbide, tan:- ,. given'a ‘preliminary sinter at about _1600°‘>-F. ‘of 5 talum carbide, titanium carbide and an auxiliary , It is cooled and :reshaped'and then given a ?nal, I , ‘ I metal, or alloy- such as cobalt, iron or nickel. sinter at a temperature of between ‘2600 and‘ Hard cemented carbide materials containing 32009.- E, . 7' . ~ - _ tungsten carbide and iron, cobalt. or nickel are The material may be made according to the ’ now known and have been described in hot-press method in which the heat ‘and pressure 65 10 Schroeter Patent No. 1,549,615. ‘ ' ‘ ' ' - ‘I ' are applied simultaneously. We’ preter in the ' In my application, Serial No. ‘512,917, filed hot-press, method to use. ‘a temperature‘ of about . November 4, 1931, there isdescribed a hard. 3200° F. and a pressure of about 140o#/sq. in'. cemented carbidematerial containing tungsten and.‘ to carry out the sintering‘for, about ?ve _ carbide, tantalum carbide and cobalt, nickel or minutes‘ at thisftemperature.
    [Show full text]
  • Microwave Sintering of Alumina-Titanium Cermets Redacted for Privacy Abstract Approved: (
    AN ABSTRACT OF THE THESIS OF Wendell R. Wrzesinski for the degree of Master of Material Science in Mechanical Engineering presented on 10-19-87. Microwave Sintering of Alumina-titanium Cermets Redacted for Privacy Abstract Approved: ( The influence of microwave radiation on the fabrication of cermet materials has been investigated for alumina-titanium cermets with compositions ranging from 20 to 80 wt. % titanium. An industrial microwave oven was characterized and adapted to process cermet materials. Physical and mechanical property determinations were made as a function of microwave processing time and compared to a furnace sintered sample. Electron microscopy was conducted on the composite materials in evaluat- ing the extent of bonding between metal and oxide particles and particle sizing in the cermet. Sintering of composite materials through microwave radiation usagemay be possible as a reduced cost, time-saving, processing technique. Microwave Sintering of Alumina-titanium Cermets by Wendell R. Wrzesinski A THESIS submitted to Oregon State University in partial fulfillment of the requirements for the degree of Master of Material Science Completed: 10-19-87 Commencement June 1988 APPROVED: Redacted for Privacy Profesqr of Material Science and Engineering incharge of major Redacted for Privacy head of department of MechanicalEngineering Redacted for Privacy Dean of Grad School Date thesis presented: 10-19-87 ACKNOWLEDGEMENT The author would like to sincerely thank Dr. JimRawers and Rick Wilson for their assistance and guidance inexperimentation and preparation involved with this thesis, the Bureau ofMines for its support, and those others who offered invaluableassistance including: Dr. Jim Rawers, Kellee Roub, and Rick Wilsonfor technical review of this manuscript, Dan Davis forpreparing furnace sintered materials, Keith Collins formicroscopic eval- uation, and Earl Peterson and Steve Anderson fortheir drafting and photography.
    [Show full text]
  • Bandgap Engineering of Titanium Based Oxynitride Thin Films and Molybdenum Disulfide Thin Films for Photovoltaic Applications
    FROESCHLE, MICHAEL R., M.S. Bandgap Engineering of Titanium Based Oxynitride Thin Films and Molybdenum Disulfide Thin Films for Photovoltaic Applications. (2019) Directed by Dr. Hemali P. Rathnayake. 70 pp. The purpose of this project was to investigate the potential of two different material systems for the improvement of solar cell efficiency; one based on a titanium oxynitride system and the other molybdenum disulfide. Both phases of the project utilized different fabrication methods and approach in designing the photovoltaic devices. For the titanium based system (TiNO), thin films were formed using pulsed laser deposition, a phase vapor deposition (PVD) technique. The photovoltaic cells deposited on ITO coated glass with copper electrodes yielded an average power conversion efficiency (PCE) of 4.47%, with a fill factor (FF) of 0.246, open circuit 2 voltage (Voc) of 0.18 V, and a short circuit current density (Jsc) of 58.43 mA/cm . XRD and XPS results provide insight into the materials composition and give evidence of multiple bandgap mediated transfer of charge carriers. For the molybdenum based device, monolayer molybdenum disulfide was incorporated into a current organic-based solar cell (OSC) as an electron transport layer. The active layer consists of a blend of donor Poly(3-hexylthiophene-2,5- diyl) and acceptor PCBM. MoS2 incorporated devices showed improved PCE, at 0.88% compared to that of the control samples which yielded a PCE of 0.22%. BANDGAP ENGINEERING OF TITANIUM BASED OXYNITRIDE THIN FILMS AND MOLYBDENUM DISULFIDE THIN FILMS FOR PHOTOVOLTAIC APPLICATIONS by Michael R. Froeschle A Thesis Submitted to the Faculty of The Graduate School at The University of North Carolina at Greensboro in Partial Fulfillment of the Requirements for the Degree Master of Science Greensboro 2019 Approved by _______________________________ Committee Chair APPROVAL PAGE This thesis written by Michael R.
    [Show full text]
  • Method for Producing Thick Ceramic Films by a Sol Gel
    Europäisches Patentamt *EP000815285B1* (19) European Patent Office Office européen des brevets (11) EP 0 815 285 B1 (12) EUROPEAN PATENT SPECIFICATION (45) Date of publication and mention (51) Int Cl.7: C23C 18/12 of the grant of the patent: // C04B41/87, C04B41/50 22.08.2001 Bulletin 2001/34 (86) International application number: (21) Application number: 96901675.7 PCT/CA96/00088 (22) Date of filing: 13.02.1996 (87) International publication number: WO 96/29447 (26.09.1996 Gazette 1996/43) (54) METHOD FOR PRODUCING THICK CERAMIC FILMS BY A SOL GEL COATING PROCESS VERFAHREN ZUR HERSTELLUNG DICKER KERAMIKFILMS DURCH SOL-GEL-BESCHICHTUNGSPROZESS PROCEDE DE FABRICATION DE FILMS DE CERAMIQUE EPAIS METTANT EN UVRE UN PROCESSUS DE REVETEMENT SOL-GEL (84) Designated Contracting States: (74) Representative: AT BE CH DE DK ES FR GB GR IE LI NL PT SE Simpson, Alison Elizabeth Fraser et al Urquhart-Dykes & Lord, (30) Priority: 22.03.1995 US 409127 30 Welbeck Street London W1G 8ER (GB) (43) Date of publication of application: 07.01.1998 Bulletin 1998/02 (56) References cited: EP-A- 0 433 915 EP-A- 0 482 659 (73) Proprietor: QUEEN’S UNIVERSITY AT KINGSTON EP-A- 0 564 866 WO-A-96/00198 Kingston Ontario K7L 3N6 (CA) US-A- 4 921 731 (72) Inventors: • TECHNICAL DISCLOSURE BULLETIN, vol. 37, • BARROW, David No 09, September 1994, "Low Leakage, Ajax, Ontario L1S 6Z4 (CA) Temperature Invariant, High Dielectric Constant • PETROFF, Edward, T. Films, using Multilayered Sol-Gel Fabrication", Scarborough, Ontario M1T 1V8 (CA) page 27 - page 28 • SAYER, Michael • PATENT ABSTRACTS OF JAPAN, vol.
    [Show full text]
  • The Titanium Industry: a Case Study in Oligopoly and Public Policy
    THE TITANIUM INDUSTRY: A CASE STUDY IN OLIGOPOLY AND PUBLIC POLICY DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy In the Graduate School of the Ohio State University by FRANCIS GEORGE MASSON, B.A., M.A. The Ohio State University 1 9 5 k Content* L £MR I. INTRODUCTION............................................................................................... 1 II. THE PRODUCT AND ITS APPLICATIONS...................................... 9 Consumption and Uses ................................. 9 Properties ........................................................ ...... 16 III. INDUSTRY STRUCTURE................................................................................ 28 Definition of the I n d u s t r y ............................................ 28 Financial Structure. ..••••••.••. 32 Alloys and Carbide Branch. ........................... 3 k Pigment Branch .............................................................................. 35 Primary Metal Branch ................................. 1*0 Fabrication Branch ................................. $0 IT. INDUSTRY STRUCTURE - CONTINUED............................................. $2 Introduction ................................ $2 World Production and Resources ................................. $3 Nature of the Demand for Ram Materials . $8 Ores and Concentrates Branch. ••••••• 65 Summary.................................................................. 70 V. TAXATION. ANTITRUST AND TARIFF POLICY............................
    [Show full text]
  • Pdf 1007.44 K
    IJE TRANSACTIONS B: Applications Vol. 29, No. 5, (May 2016) 677-687 International Journal of Engineering Journal Homepage: www.ije.ir A Review on Titanium Nitride and Titanium Carbide Single and Multilayer Coatings Deposited by Plasma Assisted Chemical Vapor Deposition a, A. Sabour Rouhaghdamb, S. Ahangaranic٭M. Azadi a Faculty of metallurgical Engineering and material, Semnan University, Semnan, Iran b Faculty of Engineering, Materials Engineering Department, Surface Engineering Laboratory ,Tarbiat Modares University, Tehran, Iran c Advanced Materials and Renewable Energies Department, Iranian Research Organization for Science and Technology, Tehran, Iran P A P E R I N F O ABSTRACT Paper history: In this paper, we reviewed researches about the titanium nitride (TiN) and titanium carbide (TiC) Received 21 September 2015 single and multilayer coatings. These coatings were deposited by the plasma assisted chemical vapor Received in revised form 06 February 2016 deposition (PACVD) technique. Plasma-based technologies are used for the processing of thin films Accepted 4 March 2016 and coatings for different applications such as automobile and aerospace parts, computer disc drives, food industry and surgical/medical instruments. We describe the state of the performance of different Keywords: coating systems and thin film architectures in PACVD suitable for industrial-scale or laboratory Titanium Nitride applications. Mechanical properties of coatings such as wear resistance, hardness and the scratch Titanium Carbide resistance, structural characteristics, physical and chemical properties like coatings adhesion into Multilayer Coatings different substrates, wetting behavior and corrosion resistance were studied. Thus, this paper represents Hard Coatings a source of information for those who want to familiarize with the status of knowledge in the area of Plasma Assisted Chemical Vapor Deposition materials science of functional coatings, in particular TiN/TiC coatings that was deposited by a new Plasma-based technologies.
    [Show full text]
  • Nasa Tm X-3265 17 Effect of Magnesium Oxide Content
    NASA TECHNICAL. NASA TM X-3265 17 MEMORANDUM CO 1 I b- ; X in.l rui LOAN COPY: RE t-1! AFWL TECHNICAL t-1: KIRTLAND AFB EFFECT OF MAGNESIUM OXIDE CONTENT ON OXIDATION BEHAVIOR OF SOME SUPERALLOY-BASE CERMETS Isidor Zaplatynsky Lewis Research Center Cleveland, Ohio 44135 \ NATIONAL AERONAUTICS AND SPACE ADMINISTRATION • WASHINIGTUlUILJD.G - • AUGUST 1975 ERRATA NASA Technical Memorandum X-3265 EFFECT OF MAGNESIUM OXIDE CONTENT ON OXIDATION BEHAVIOR OF SOME SUPERALLOY-BASE CERMETS by Isidor Zaplatynsky August 1975 The composition of the alloy listed as Hastelloy X in table I, page 9, does not fit the specifications for HASTELLOY ® (a registered trademark of the Cabot Corporation) alloy X. Further, an analysis of this alloy indicated deviation from the specifications shown in table I. The following corrected table shows the correct analysis of this alloy, henceforth called Alloy A. Thus, throughout the report, references to Hastelloy X should be read to mean Alloy A. Further, references to Inconel-702 should be read to meanlNCONEL ® alloy 702. ERRATA NASA Technical Memorandum X-3265 EFFECT OF MAGNESIUM OXIDE CONTENT ON OXIDATION BEHAVIOR OF SOME SUPERALLOY-BASE CERMETS by Isidor Zaplatynsky August 1975 The composition of the alloy listed as Hastelloy X in table I, page 9, does not fit the specifications for HASTELLOY © (a registered trademark of the Cabot Corporation) alloy X. Further, an analysis of this alloy indicated deviation from the specifications shown in table I. The following corrected table shows the correct analysis of this alloy, henceforth called Alloy A. Thus, throughout the report, references to Hastelloy X should be read to mean Alloy A.
    [Show full text]
  • Repository Criticality Control with Depleted-Uranium-Dioxide Cermet Waste Packages
    —Summary— REPOSITORY CRITICALITY CONTROL WITH DEPLETED-URANIUM-DIOXIDE CERMET WASTE PACKAGES Charles W. Forsberg Oak Ridge National Laboratory* P.O. Box 2008 Oak Ridge, Tennessee 37831-6180 Tel: (865) 574-6783 Fax: (865) 574-9512 Email: [email protected] File Name: Cermet.DuCermet.Criticality Session: Geological Disposal Prepared for Session: Geological Disposal Embedded Topical Meeting on Practical Implementation of Nuclear Criticality Safety American Nuclear Society Reno, Nevada November 11–15, 2001 Limit: 1000 words Actual: 823 words The submitted manuscript has been authored by a contractor of the U.S. Government under contract DE-AC05-00OR22725. Accordingly, the U.S. Government retains a nonexclusive, royalty-free license to publish or reproduce the published form of this contribution, or allow others to do so, for U.S. Government purposes. _________________________ *Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725. REPOSITORY CRITICALITY CONTROL WITH DEPLETED URANIUM DIOXIDE CERMET WASTE PACKAGES It is proposed that the structural components and internal basket structures of spent nuclear fuel (SNF) waste packages (WPs), which will be sequestered with the SNF at the repository, be constructed of depleted uranium dioxide (DUO2 )–steel cermets. The cermet used for the WP basket would also contain neutron absorbers with high-absorption-cross-sections such as boron or rare earth oxides. This strategy would provide both operational and long-term (repository post-closure) criticality control. As the WP degrades, the 238U in the depleted uranium (DU) would mix with the degrading SNF and isotopically dilute 233U and 235U to levels (<1 wt % 235U in 238U; <0.66 wt % 233U in 238 U) that ensure critically will not occur.
    [Show full text]
  • Additive Manufacturing of Ceramics and Cermets: Present Status and Future Perspectives
    Sådhanå Ó (2021) 46:162 Indian Academy of Sciences https://doi.org/10.1007/s12046-021-01685-2Sadhana(0123456789().,-volV)FT3](0123456789().,-volV) Additive manufacturing of ceramics and cermets: present status and future perspectives MAINAK SAHA1,2,* and MANAB MALLIK1,* 1 Department of Metallurgical and Materials Engineering, National Institute of Technology, Durgapur 713209, West Bengal, India 2 Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Madras 600036, Tamil Nadu, India e-mail: [email protected]; [email protected] MS received 6 November 2020; revised 19 May 2021; accepted 6 July 2021 Abstract. The present decade has witnessed a huge volume of research revolving around a number of Additive Manufacturing (AM) techniques, especially for the fabrication of different metallic materials. How- ever, fabrication of ceramics and cermets using AM-based techniques mainly suffers from two primary limi- tations which are: (i) low density and (ii) poor mechanical properties of the final components. Although there has been a considerable volume of work on AM based techniques for manufacturing ceramic and cermet parts with enhanced densities and improved mechanical properties, however, there is limited understanding on the cor- relation of microstructure of AM-based ceramic and cermet components with the mechanical properties. The present article is aimed to review some of the most commonly used AM techniques for the fabrication of ceramics and cermets. This has been followed by a brief discussion on the microstructural developments during different AM-based techniques. In addition, an overview of the challenges and future perspectives, mainly associated with the necessity towards developing a systematic structure-property correlation in these materials has been provided based on three factors viz.
    [Show full text]
  • Some Neutron and Gamma Radiation Characteristics of Plutonium Cermet
    Some Neutron and Gamma Radiation Characteristics of Plutonium Cermet Fuel for Isotopic Power Sources R. A. NEFF, M. E. ANDERSON, A. R. CAMPBELL, and F. X. HAAS Mound Laboratory, Miamisburg, Ohio* Gamma and neutron measurements on various types of plutonium sources are presented in order to show the effects of ZTO, ZSO, ZSF, S3SPu, age of the fuel, and size of the source on the gamma and neutron spectra. Analysis of the radiation measurements shows that fluorine is the main contributor to the neutron yields from _resent plutonium-molybdenum cermet fuel while both fluorine and s Spu daughters contribute significantly to the gamma-ray intensities. Plutonium-238 has many desirable qual- The fuel used in heat sources is nomi- ities for a radioisotopic heat source fuel nally about 80% a=SPu, 16% _SgPu, and 1.2 and has been used in numerous heat sources ppm =36Pu. The _39Pu contributes a group for terrestrial, marine and space applica- of peaks around 400 keV while the main tions. The plutonium fuel has been pre- contributions from _3SPu are the two in- pared in several different forms depending tense peaks at 2614 and 583 keV due to on the requirements of the particular mis- the =°STI daughter. Other peaks from a3ePu sion and the technology available at the daughters which can be seen in this spec- time of fabrication. Fuel forms used in trum are the 510 and 860 keV peaks also the past have been plutonium metal, alloys, from S°STl, the 240 and 301 keV peaks from and dioxide microspheres. The most recent _1sPb, and the 727 and 1620 keV peaks from fuel form to be used is plutonium,molybde- SZ2Bi.
    [Show full text]
  • Grain Refinement of Aluminium by Titanium Diboride Particles
    EXAMENSARBETE INOM KEMIVETENSKAP, AVANCERAD NIVÅ, 30 HP STOCKHOLM, SVERIGE 2019 Grain refinement of aluminium by titanium diboride particles The importance of nucleation, growth restriction, and cooling rate SOFIA CARLSSON KTH SKOLAN FÖR INDUSTRIELL TEKNIK OCH MANAGEMENT ABSTRACT The grain refinement of aluminium by titanium diboride particles, TiB2, using Ti/B grain refiners is common practice in the aluminium industry, but exactly how this grain refinement is achieved is uncertain. Current addition of grain refiner is therefore rarely optimal and excessive addition rates of grain refiner is common. This study investigates grain refinement of aluminium by titanium diboride to create a method and/or model which can be used to aid in addition rate optimisation. The effect of different parameters on grain refinement is the focus and includes cooling rate, properties of the nucleant particles, and growth restriction. A number of experiments using different test methods was applied to investigate this. The study reveals how the parameters investigated affect grain refinement, and how these can be used to optimises grain refiner addition rate. A model aiding in dealing with the varying abilities of nominally identical grain refiners to produce grains is introduced. The conclusion emphasizes the importance of optimising addition rates of grain refiners, for mechanical as well as environmental reasons, and how this can be achieved by changing the investigated parameters. SAMMANFATTNING Kornförfining av aluminium med titandiboridpartiklar, TiB2, genom användning av Ti/B kornförfinare är standard inom aluminiumindustrin. Det är dock inte helt utrett hur denna kornförfining går till. Rådande tillsatsmängder av kornförfinare är därför sällan optimala och alltför stora tillsatsmängder av kornförfinare är vanligt förkommande.
    [Show full text]
  • Fabrication of Tib2–Al1050 Composites with Improved Microstructural and Mechanical Properties by a Liquid Pressing Infiltration Process
    materials Article Fabrication of TiB2–Al1050 Composites with Improved Microstructural and Mechanical Properties by a Liquid Pressing Infiltration Process Seongmin Ko 1,2, Hyeonjae Park 3, Yeong-Hwan Lee 1,2, Sangmin Shin 1,2, Ilguk Jo 3, Junghwan Kim 1, Sang-Bok Lee 1, Yangdo Kim 2,*, Sang-Kwan Lee 1,* and Seungchan Cho 1,* 1 Composites Research Division, Korea Institute of Materials Science (KIMS), Changwon 51508, Korea; [email protected] (S.K.); [email protected] (Y.-H.L.); [email protected] (S.S.); [email protected] (J.K.); [email protected] (S.-B.L.) 2 School of Materials Science and Engineering, Pusan National University, Busan 46241, Korea 3 Advanced Materials Engineering, Dong-Eui University, Busan 47340, Korea; [email protected] (H.P.); [email protected] (I.J.) * Correspondence: [email protected] (Y.K.); [email protected] (S.-K.L.); [email protected] (S.C.) Received: 9 March 2020; Accepted: 25 March 2020; Published: 30 March 2020 Abstract: This study was conducted on titanium diboride (TiB2) reinforced Al metal matrix composites (MMCs) with improved properties using a TiB2 and aluminum (Al) 1050 alloy. Al composites reinforced with fine TiB2 at volume ratios of more than 60% were successfully fabricated via the liquid pressing infiltration (LPI) process, which can be used to apply gas pressure at a high temperature. The microstructure of the TiB2–Al composite fabricated at 1000 ◦C with pressurization of 10 bar for 1 h showed that molten Al effectively infiltrated into the high volume-fraction TiB2 preform due to the improved wettability and external gas pressurization.
    [Show full text]