DOCSLIB.ORG

Effects of Microstructure on the Spall Behavior of Aluminum-Magnesium Alloys Byrickyl.Whelchel

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Effects of Microstructure on the Spall Behavior of Aluminum-Magnesium Alloys Byrickyl.Whelchel EFFECTS OF MICROSTRUCTURE ON THE SPALL BEHAVIOR OF ALUMINUM-MAGNESIUM ALLOYS BYRICKYL.WHELCHEL A Thesis Presented to The Academic Faculty by Ricky L. Whelchel In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the School of Materials Science and Engineering Georgia Institute of Technology March 2014 Copyright c 2014 by Ricky L. Whelchel EFFECTS OF MICROSTRUCTURE ON THE SPALL BEHAVIOR OF ALUMINUM-MAGNESIUM ALLOYS BYRICKYL.WHELCHEL Approved by: Dr. Naresh Thadhani, Advisor Dr. Sunil Dwivedi School of Materials Science and School of Materials Science and Engineering Engineering Georgia Institute of Technology Georgia Institute of Technology Dr. Thomas Sanders Jr., Co-Advisor Dr. Suveen Mathaudhu School of Materials Science and Synthesis and Processing Engineering Army Research Office Georgia Institute of Technology Dr. Arun M. Gokhale Victor Dangerfield School of Materials Science and Research and Development Engineering Universal Alloys Corporation Georgia Institute of Technology Date Approved: 24 February 2014 ACKNOWLEDGEMENTS I would like to gratefully acknowledge the funding provided for this research provided by the United States Army Research Office under grant number W911NF-09-1-0403. I wish to express my gratitude to my two thesis advisors, Dr. Naresh Thadhani and Dr. Thomas Sanders, for providing me with a project for my PhD thesis and for their advice and assistance throughout my time in the School of Materials Science and Engineering at the Georgia Institute of Technology. Their guidance throughout the years has been critical in my success as a graduate student. I also wish to thank my committee members Dr. Arun Gokhale, Dr. Sunil Dwivedi, Dr. Suveen Mathaudhu, and Victor Dangerfield for agreeing to serve on my committee and providing helpful advice towards the completion of my thesis. Dr. Gregory Kennedy deserves special thanks for his constant help, support, and ex- perimental expertise. His contributions towards my individual learning of high strain-rate and plate impact testing were invaluable to me as a researcher. Finally, I wish to thank both of my research groups under Dr. Thadhani and Dr. Sanders for providing guidance and teamwork during my graduate studies. iii TABLE OF CONTENTS ACKNOWLEDGEMENTS .............................. iii LIST OF TABLES ................................... viii LIST OF FIGURES .................................. ix SUMMARY ........................................ xiv 1 INTRODUCTION ................................. 1 2 BACKGROUND .................................. 4 2.1Al-MgAlloyMicrostructure.......................... 4 2.1.1 Grain Structure and Recrystallization ................. 6 2.1.2 SecondaryPhases............................ 9 2.2 Novel Processing Techniques for Al-Mg Alloys ................ 10 2.2.1 Equi-Channel Angular Pressing (ECAP) ............... 11 2.2.2 PrecipitationHardening........................ 18 2.3ShockCompressionandDynamicDeformation................ 19 2.4 Spalling ..................................... 24 2.4.1 Shock Wave Propagation ........................ 24 2.4.2 CalculationofHELandSpallStrength................ 28 2.5 Spalling of Polycrystalline Metals ....................... 29 2.6SpallDamageModels.............................. 32 2.6.1 DavisonandStevensModels...................... 33 2.6.2 Stanford Research Institute Model .................. 36 2.6.3 CochranandBannerModel...................... 39 2.7 Effects of Peak Stress, Strain Rate, and Duration on the Spall Strength and HugoniotElasticLimitofDuctileMaterials................. 40 2.7.1 EffectsofPeakStressonSpallStrength............... 42 2.7.2 Effects of Decompression Strain Rate on Spall Strength ....... 42 2.7.3 EffectsofShockDurationonSpallStrength............. 46 2.7.4 Elastic Precursor Decay and Strain Rate Dependence of the Hugo- niotElasticLimit............................ 48 iv 3 EXPERIMENTAL PROCEDURE ....................... 53 3.1Materials..................................... 53 3.2MicrostructureCharacterization........................ 55 3.3UltrasonicTesting................................ 56 3.4PlateImpactGasGunExperiments...................... 57 3.5Post-ImpactRecovery.............................. 59 3.6NumericalModeling............................... 59 3.7 Presentation of the Results ........................... 61 4 EFFECT OF PULSE DURATION AND DECOMPRESSION RATE ON THE SPALL STRENGTH OF AL 5083-H116 ............... 63 4.1ExperimentalProcedure............................ 64 4.1.1 Materials................................. 64 4.1.2 PlateImpactGasGunExperiments.................. 64 4.2Results...................................... 66 4.2.1 FreeSurfaceVelocity.......................... 66 4.2.2 SpallStrengthandHEL........................ 66 4.3Conclusions................................... 72 5 SPALL BEHAVIOR OF ROLLED AL 5083-H116 PLATE ........ 73 5.1ExperimentalProcedure............................ 74 5.1.1 Materials................................. 74 5.1.2 PlateImpactExperiments....................... 76 5.2Results...................................... 77 5.2.1 FreeSurfaceVelocity.......................... 77 5.2.2 SpallStrengthandHEL........................ 81 5.3Post-ImpactRecoveredMicrostructureCharacterization.......... 84 5.4Conclusions................................... 86 6 SPALL BEHAVIOR OF AL 5083 PLATE FABRICATED USING EQUI- CHANNEL ANGULAR PRESSING (ECAP) AND ROLLING .... 89 6.1ExperimentalProcedure............................ 89 6.1.1 Materials................................. 89 6.1.2 PlateImpactExperiments....................... 92 v 6.2Results...................................... 92 6.2.1 Microstructure.............................. 93 6.2.2 PlateImpactExperimentResults................... 96 6.3Conclusions................................... 101 7 SPALL BEHAVIOR OF AL 5083 WITH AN EQUIAXED GRAIN STRUC- TURE ......................................... 107 7.1ExperimentalProcedure............................ 107 7.1.1 Materials................................. 107 7.1.2 PlateImpactExperiments....................... 108 7.2Results...................................... 110 7.2.1 FreeSurfaceVelocity.......................... 110 7.2.2 SpallStrengthandHEL........................ 111 7.3Conclusions................................... 113 8 SPALL BEHAVIOR OF PRECIPITATION HARDENED ALUMINUM- 9WT.% MAGNESIUM .............................. 114 8.1ExperimentalProcedure............................ 114 8.1.1 Materials................................. 114 8.1.2 HeatTreatments............................ 115 8.1.3 PlateImpactExperiments....................... 116 8.2Results...................................... 117 8.2.1 SolutionTreatment........................... 117 8.2.2 AgeHardening............................. 119 8.2.3 ResultsofPlateImpactExperiments................. 128 8.3Conclusions................................... 134 9 ONE-DIMENSIONAL NUMERICAL MODELING OF THE SPALL RE- SPONSE OF AL 5083 ............................... 136 9.1Procedure.................................... 136 9.1.1 PlateImpactExperiments....................... 136 9.1.2 One-DimensionalSimulations..................... 137 9.2Results...................................... 138 9.2.1 PeakStressandEquationofState................... 138 vi 9.2.2 ModelingofSpallResponse...................... 144 9.3ComparisonofMicrostructuretoSimulation................. 149 9.3.1 GrainSize................................ 149 9.3.2 InclusionandDispersoidSize..................... 151 9.4Conclusions................................... 157 10 INFLUENCE OF MICROSTRUCTURE ON SPALL STRENGTH AND HUGONIOT ELASTIC LIMIT IN AL-MG ALLOYS .......... 160 10.1PeakStressDependenceoftheHELandSpallStrength........... 160 10.1.1HugoniotElasticLimit(HEL)..................... 160 10.1.2SpallStrength.............................. 162 10.2GrainSizeDependenceoftheHELandSpallStrength........... 164 10.2.1HugoniotElasticLimit(HEL)..................... 164 10.2.2SpallStrength.............................. 165 10.3 Decompression Rate Dependence of the Spall Strength ........... 165 10.3.1 Effects of Al 5083 Microstructure ................... 168 10.3.2EffectsofImpactOrientation..................... 170 10.3.3TrendsinPowerLawFits....................... 170 10.4Conclusion....................................175 11 SUMMARY AND CONCLUSIONS ...................... 176 11.1SummaryofResults............................... 176 11.2Conclusions................................... 182 11.3SuggestionsforFutureWork.......................... 183 APPENDIX A — EQUATION OF STATE .................. 185 APPENDIX B — VOID SIZE DISTRIBUTIONS .............. 187 BIBLIOGRAPHY .................................... 191 VITA ............................................ 201 vii LIST OF TABLES 1 Measured sound speed and elastic constants for Al 5083-H116 samples mea- suredthroughtheplatethickness........................ 65 2 Calculated and measured free surface velocity data for Al 5083-H116 samples with different flyer plate and sample thicknesses ................ 68 3 Material properties of Al 5083-H116 along the three principal directions of a rolledplate.................................... 76 4 Calculated and measured free surface velocity data for Al 5083-H116 .... 82 5 Measured sound speed, density, and elastic constants for Al 5083 samples processed using ECAP and post-ECAP rolling ................ 91 6 Calculated and measured free surface velocity data for Al 5083 samples pro- cessed using ECAP and rolling ......................... 100 7 Measured sound speed and elastic
Load more

Recommended publications
  • Probing Pulse Structure at the Spallation Neutron Source Via Polarimetry Measurements
    University of Tennessee, Knoxville TRACE: Tennessee Research and Creative Exchange Masters Theses Graduate School 5-2017 Probing Pulse Structure at the Spallation Neutron Source via Polarimetry Measurements Connor Miller Gautam University of Tennessee, Knoxville, [email protected] Follow this and additional works at: https://trace.tennessee.edu/utk_gradthes Part of the Nuclear Commons Recommended Citation Gautam, Connor Miller, "Probing Pulse Structure at the Spallation Neutron Source via Polarimetry Measurements. " Master's Thesis, University of Tennessee, 2017. https://trace.tennessee.edu/utk_gradthes/4741 This Thesis is brought to you for free and open access by the Graduate School at TRACE: Tennessee Research and Creative Exchange. It has been accepted for inclusion in Masters Theses by an authorized administrator of TRACE: Tennessee Research and Creative Exchange. For more information, please contact [email protected]. To the Graduate Council: I am submitting herewith a thesis written by Connor Miller Gautam entitled "Probing Pulse Structure at the Spallation Neutron Source via Polarimetry Measurements." I have examined the final electronic copy of this thesis for form and content and recommend that it be accepted in partial fulfillment of the equirr ements for the degree of Master of Science, with a major in Physics. Geoffrey Greene, Major Professor We have read this thesis and recommend its acceptance: Marianne Breinig, Nadia Fomin Accepted for the Council: Dixie L. Thompson Vice Provost and Dean of the Graduate School (Original signatures are on file with official studentecor r ds.) Probing Pulse Structure at the Spallation Neutron Source via Polarimetry Measurements A Thesis Presented for the Master of Science Degree The University of Tennessee, Knoxville Connor Miller Gautam May 2017 c by Connor Miller Gautam, 2017 All Rights Reserved.
    [Show full text]
  • Explosive Weapon Effectsweapon Overview Effects
    CHARACTERISATION OF EXPLOSIVE WEAPONS EXPLOSIVEEXPLOSIVE WEAPON EFFECTSWEAPON OVERVIEW EFFECTS FINAL REPORT ABOUT THE GICHD AND THE PROJECT The Geneva International Centre for Humanitarian Demining (GICHD) is an expert organisation working to reduce the impact of mines, cluster munitions and other explosive hazards, in close partnership with states, the UN and other human security actors. Based at the Maison de la paix in Geneva, the GICHD employs around 55 staff from over 15 countries with unique expertise and knowledge. Our work is made possible by core contributions, project funding and in-kind support from more than 20 governments and organisations. Motivated by its strategic goal to improve human security and equipped with subject expertise in explosive hazards, the GICHD launched a research project to characterise explosive weapons. The GICHD perceives the debate on explosive weapons in populated areas (EWIPA) as an important humanitarian issue. The aim of this research into explosive weapons characteristics and their immediate, destructive effects on humans and structures, is to help inform the ongoing discussions on EWIPA, intended to reduce harm to civilians. The intention of the research is not to discuss the moral, political or legal implications of using explosive weapon systems in populated areas, but to examine their characteristics, effects and use from a technical perspective. The research project started in January 2015 and was guided and advised by a group of 18 international experts dealing with weapons-related research and practitioners who address the implications of explosive weapons in the humanitarian, policy, advocacy and legal fields. This report and its annexes integrate the research efforts of the characterisation of explosive weapons (CEW) project in 2015-2016 and make reference to key information sources in this domain.
    [Show full text]
  • MS Owen-Smith. Armoured Fighting Vehicle Casualties
    J R Army Med Corps: first published as 10.1136/jramc-123-02-03 on 1 January 1977. Downloaded from J. roy. Army med. Cps. 1977. 123,65-76 ARMOURED FIGHTING VEHICLE CASUALTIES * Lieutenant-Colonel M. S. OWEN-SMITH, M.S., F.R.C.S. Professor of Surgery, Royal Army Medical College THE war between the Arabs and Israelis in October 1973 resulted in the most extensive tank battles since World War n. Indeed in one area involved they were claimed to be the most extensive in Military history, exceeding the 1600 tanks deployed at El Alamein. In.association with these battles some 830 Israeli tanks and about 1400 Arab tanks were destroyed. The Israelis have recorded data on the wounded from this war in a number of articles and presentations. The most striking figure is that just under 10 per cent of all injured suffered burns. Virtually all these burns occurred in Armoured Fighting Vehicle (A.F.V.) crews. The problems I want to discuss are: a. Does the total incidence of burns from major tank battles create a definite departure from previous experiences and must we, therefore, include this figure in pre- planning for conflict in N.W. Europe? . guest. Protected by copyright. b. Does the present range of anti-tank weapons pose a greater threat to tanks and, crew than those of 30 years ago? c. Is there such an entity as " The Anti-Tank Missile Burn Syndrome"? d. What medical lessons can we learn from this war that would benefit the treatment of war wounded in general, and A.F.V.
    [Show full text]
  • Capstone Depleted Uranium Aerosols: Generation and Characterization Volume 1
    PNNL-14168 Capstone Depleted Uranium Aerosols: Generation and Characterization Volume 1. Main Text Attachment 1 of Depleted Uranium Aerosol Doses and Risks: Summary of U.S. Assessments M. A. Parkhurst, J. W. Collins Principal Investigator T. E. Sanderson F. Szrom R. W. Fliszar R. A. Guilmette K. Gold T. D. Holmes J. C. Beckman Y. S. Cheng J. A. Long J. L. Kenoyer October 2004 Prepared for the U.S. Department of the Army under a Related Services Agreement with the U.S. Department of Energy under Contract DE-AC06-76RL01830 DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor Battelle Memorial Institute, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof, or Battelle Memorial Institute. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. PACIFIC NORTHWEST NATIONAL LABORATORY operated by BATTELLE for the UNITED STATES DEPARTMENT OF ENERGY under Contract DE-AC06-76RL01830 Printed in the United States of America Available to DOE and DOE contractors from the Office of Scientific and Technical Information, P.O.
    [Show full text]
  • The Actinide Research Quarterly Highlights Recent Achievements and Ongoing Programs of the Nuclear Materials Technology (NMT) Division
    1st quarter 2001 TheLos Actinide Alamos National Research Laboratory N u c l e a r M Quarterlya t e r i a l s R e s e a r c h a n d T e c h n o l o g y Researcher Provides a Historical Perspective for Plutonium Heat Sources In This Issue We begin the seventh year of Actinide Research Quarterly For more than 30 years, by focusing on Los Alamos has designed, major programs in 4 developed, manufactured, NMT Division. The Pit Manufacturing and tested heat sources for publication team Project Presents Many radioisotope thermoelectric also welcomes its Challenges generators (RTGs). These new editor, Meredith powerful little “nuclear “Suki” Coonley, who is 6 batteries” produce heat assuming the position Can Los Alamos from the decay of radioac- while Ann Mauzy Meet Its Future Nuclear tive isotopes—usually takes on acting Challenges? plutonium-238—and can management provide electrical power duties in IM-1. 9 and heat for years in Detecting and satellites, instruments, K.C. Kim Predicting Plutonium and computers. Aging are Crucial to continued on page 2 Stockpile Stewardship 12 Pit Disassembly and Conversion Address a ‘Clear and Present Danger’ 14 Publications and Invited Talks Newsmakers 15 Energy Secretary Spencer Abraham Addresses Employees artist rendering of Rover Pathfinder on Mars from NASA/JPL Nuclear Materials Technology/Los Alamos National Laboratory 1 Actinide Research Quarterly This article was contributed by Gary Rinehart (NMT-9) Early development efforts from the Each Multihundred Watt RTG provided about 157 mid-1960s through the early 1970s focused watts of power at the beginning of the mission.
    [Show full text]
  • Ballistic Penetration of Hardened Steel Plates
    BALLISTIC PENETRATION OF HARDENED STEEL PLATES A THESIS SUBMITTED TO THE GRADUATE SCHOOL OF NATURAL AND APPLIED SCIENCES OF MIDDLE EAST TECHNICAL UNIVERSITY BY TANSEL DENIZ˙ IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN MECHANICAL ENGINEERING AUGUST 2010 Approval of the thesis: BALLISTIC PENETRATION OF HARDENED STEEL PLATES submitted by TANSEL DENIZ˙ in partial fulfillment of the requirements for the degree of Master of Science in Mechanical Engineering Department, Middle East Technical Uni- versity by, Prof. Dr. Canan Ozgen¨ Dean, Graduate School of Natural and Applied Sciences Prof. Dr. S¨uha Oral Head of Department, Mechanical Engineering Prof. Dr. R. Orhan Yıldırım Supervisor, Mechanical Engineering Department Examining Committee Members: Prof. Dr. Metin Akk¨ok Mechanical Engineering Dept., METU Prof. Dr. R. Orhan Yıldırım Mechanical Engineering Dept., METU Prof. Dr. Can C¸o˘gun Mechanical Engineering Dept., METU Asst. Prof. Dr. Yi˘git Yazıcıo˘glu Mechanical Engineering Dept., METU Dr. Rıdvan Toroslu Aselsan Elektronik Sanayi ve Ticaret A.S¸. Date: I hereby declare that all information in this document has been obtained and presented in accordance with academic rules and ethical conduct. I also declare that, as required by these rules and conduct, I have fully cited and referenced all material and results that are not original to this work. Name, Last Name: TANSEL DENIZ˙ Signature : iii ABSTRACT BALLISTIC PENETRATION OF HARDENED STEEL PLATES Deniz, Tansel M.Sc., Department of Mechanical Engineering Supervisor : Prof. Dr. R. Orhan Yıldırım August 2010, 113 pages Ballistic testing is a vital part of the armor design. However, it is impossible to test every condition and it is necessary to limit the number of tests to cut huge costs.
    [Show full text]
  • ARMOR Anti- ARMOR Materials by Design by Donald J
    Armor/Anti-Armor ARMOR anti- ARMOR materials by design by Donald J. Sandstrom magine tank armor that grains aligned in a sheet of ura- chews up a high-velocity nium that allow it to stretch into a projectile on impact . or long, lethal jet of unbroken metal. I composites of tungsten and These examples illustrate how uranium that lend an antitank Los Alamos is using its knowl- penetrator rod the stiffness of edge of materials to design and the tungsten. the density and py - fabricate new and stronger com- rophoric property of the uranium, ponents for both armor and pene- and the surprising strength of trators of armor. their mixture or tiny crystal Our interest in applying ma- 36 Los Alamos Science Summer 1989 terials research to conventional tive process of theory, design. There is also a complementarily weapons has its origins in the fabrication, and testing used to between the applications of mate- Laboratory’s nuclear weapons develop nuclear weapons serves rials in conventional and nuclear program. To deal with the unique as the basis for a similar process weapons-one that has a syner- materials used in nuclear weap- in developing conventional ord- gistic effect on both programs, A ons, such as actinides, special ce- nance. The attention to detail in nuclear weapon releases so much ramics, polymers, and so forth, material properties required for energy so rapidly that materials the Laboratory had to develop nuclear weapons is, perhaps, even behave much like isotropic fluids significant expertise in materi- more important for conventional and can usually be described by als research.
    [Show full text]
  • Fracture Patterns and Spall Velocities II. Craters in Carbonate Rocks: an Electron Paramagnetic Resonance Analysis of Shock Damage Thesis by Carol Ann Polanskey
    I. Impact Spallation Experiments: Fracture Patterns and Spall Velocities II. Craters in Carbonate Rocks: An Electron Paramagnetic Resonance Analysis of Shock Damage Thesis by Carol Ann Polanskey In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy California Institute of Technology Pasadena, California 1989 (submitted September 22 , 1988) (revised May 24, 1989) 11 @ MCMLXXXIX Carol Ann Polanskey All Rights Reserved lll Tl1e following is dedicated to my parents, Walter and Mary Polanskey, my grandmother, Laura Gaul, and my friend, Maria L1es Etchegaray IV ACKNOWLEDGEMENTS - when you come right to it, it's a Jot easier to die than it is to use your head. Robert A. Heinlein I would like to thank my thesis advisor, Dr. Thomas Ahrens, for giving me a second chance many years ago when I really needed one. I am indebted to Dr. Jay Melosh, not only for publishing the theory which provided the framework for the first part of my dissertation, but more importantly for the support. and encouragement he has given since the first day we met. I am also very grateful to my academic advisor, Dr. Donald Burnett for his gentle guidance and the little extras he threw my way. My educational experience was greatly enhanced by the influence of Dr. Gene Shoemaker and Dr. Robert Sharp. Gene Shoemaker provided valuable help with the Meteor Crater project, but was an inspiration to me long before I arrived· at Caltech. Bob Sharp introduced me to the wonders of California (giving the word "fieldtrip" a whole new meaning), while also indulging me in one of my favorite past times - singing around the campfire.
    [Show full text]
  • Quarterly the Actinide Research
    4th quarter 2001 TheLos Actinide Alamos National Research Laboratory N u c l e a r M Quarterlya t e r i a l s R e s e a r c h a n d T e c h n o l o g y a U.S. Department of Energy Laboratory Researchers Use Transmission Electron Microscopy to Observe Helium Bubbles in Plutonium Los Alamos, Livermore, and Aldermaston In This Issue Collaborate on Plutonium-Aging Study Mark Wall of Lawrence Livermore National The ability to directly image self-irradiation damage accumulation Laboratory uses in plutonium is critical to understanding aging. Scientists know that Livermore’s powerful helium is building up in plutonium metal during self-irradiation. transmission electron What they don’t know is what is happening to that helium over time, microscope to image and how it ultimately affects the behavior of plutonium over long periods. a sample. Los Alamos Researchers from Los Alamos and Lawrence Livermore national researchers are collaborating with laboratories and the Atomic Weapons Establishment at Aldermaston Livermore and the 4 in the United Kingdom are col- Shock-Wave Research Atomic Weapons laborating on a study to observe Establishment at on Plutonium Yields the microstructural effects New Information Aldermaston, United caused by the formation of Kingdom, to study the Concerning Dynamic helium atoms and vacancies microstructural effects Material Properties during self-irradiation. of the buildup of Recent studies using helium in aging 6 Livermore’s state-of-the-art plutonium. Recent A Personal Perspective Transmission Electron Microscopy research has revealed on Issues in Science (TEM) facility have revealed the the existence of minute and Technology in existence of minute—approxi- bubbles too tiny to be seen with conventional NMT Division mately 1 nanometer TEM instruments.
    [Show full text]
  • September 7, 2018, Board Letter Providing Its Evaluation of the Uranium Airborne Release Fraction (ARF) and Respirable Fraction
    DEFENSE NUCLEAR FACILITIES SAFETY BOARD Staff Issue Report July 3, 2018 MEMORANDUM FOR: C. J. Roscetti, Technical Director COPIES: Board Members FROM: J. Abrefah SUBJECT: Airborne Release Parameters for Uranium Alloys Members of the Defense Nuclear Facilities Safety Board’s (Board) technical staff reviewed the results of a research project at the Y-12 National Security Complex (Y-12) to determine airborne release fraction (ARF) and respirable fraction (RF) values for metallic uranium and its alloys involved in fires. Y-12 performed the research as part of the Nuclear Safety Research and Development (NSR&D) program [1–4]. The focus of the experimental work was to determine ARF and RF values for Y-12’s inventory of metallic uranium that could be used in the safety analysis of potential fires in a defense nuclear facility. Y-12 expected its experimental results to justify using lower values of ARF*RF for its safety analysis instead of the bounding value of 1E-3 listed in Department of Energy (DOE) Handbook DOE-HDBK-3010-94, (Handbook 3010), Airborne Release Fractions/Rates and Respirable Fractions for Nonreactor Nuclear Facilities [5]. Background. DOE safety analysts use ARFs and RFs (or their product, ARF*RF) in calculating the dose consequences of radionuclides released in accidents involving a nuclear facility, such as fires. The DOE guidance for choosing ARF and RF values for various accident conditions and radionuclide material forms is found in Handbook 3010. Handbook 3010 was principally authored by Jofu Mishima and D. Pinkston of the Science Application International Corporation, who used experimental results available at the time to derive bounding values for ARF and RF.
    [Show full text]
  • RP-24: How to Knock out a Tank Kinetic Energy
    Page 1 of 20 RP-24: How to Knock Out a Tank Researched and Written by: Cdr (Ret’d) Mark Tunnicliffe Introduction When the tank made its first appearance in battle at Flers-Courcelette in September 1916, its main obstacle was not enemy action so much as mechanical break-down and getting stuck in the tormented terrain of the Somme battlefield. The armour of First World War tanks was intended to provide protection from infantry small arms, machine guns and spent artillery fragments. As the field artillery of the day had been driven back from the forward edge of the battlefield by machine guns, it was not initially well placed to counter the new threat. Nevertheless, the Germans quickly learned to hide a number of small (37mm calibre) field pieces to cover areas where they could channel tank attacks and to provide their infantry with improvised grenades to lob onto the top of the slow-moving vehicles. By 1918 they had developed a 13mm Mauser rifle with a 13mm hard steel core bullet which was capable of piercing the 8 – 22mm of armor on tanks like the museum’s M1918 (a US copy of the Renault FT). Wartime experience coupled with the increasing armor thickness of vehicles developed in the inter-war years brought with it the realization that the extemporaneous use of field artillery in the anti-tank role was, except in an emergency, not very efficient or effective. Furthermore, modified rifles were not likely to be of much use either (though these, like the British Boys rifle continued to be produced into the early years of WW2).
    [Show full text]
  • Neutron Shielding Materials
    Neutron Shielding Materials Daniel R. McAlister, Ph.D. PG Research Foundation, Inc. 1955 University Lane Lisle, IL 60532, USA Revision 2.1 February 25, 2016 INTRODUCTION Understanding the fundamentals of the interactions of neutrons with matter is an important step in working safely in areas where neutron radiation may be encountered. The following monograph will cover the basic principles and terminology of neutron sources and shielding. A more detailed treatment of each topic may be found in references [1-5]. DEFINITION OF COMMON TERMS Barn – The standard unit for neutron cross sections, equal to 10-24 cm2, denoted by the symbol b. Typical cross section values range between 0.001 and 1000 barns(b). Compound Nucleus – An unstable nucleus formed during neutron capture. The neutron combines with the target nucleus, adding its kinetic energy and binding energy, forming a new nucleus in an excited state. If sufficient energy is present, one or more nucleons from the compound nucleus may overcome nuclear binding forces and escape the nucleus in a process called evaporation. Excess energy may also be released in the form of gamma radiation. The typical lifetime of a compound nucleus is 10-14 to 10-20 seconds. Cross Section – A value which describes the probability that a nuclear reaction will occur. For neutrons, the cross section is related to the geometric cross section of the target nucleus. Therefore, cross sections are typically expressed in cm2 or barns(b) = 10-24 cm2. The cross section for a given nuclear interaction is also dependent on other factors, such as the speed of the neutron, the type of interaction (scattering, capture, etc..), and the stability of the target nucleus.
    [Show full text]