UNLV Theses, Dissertations, Professional Papers, and Capstones August 2016 CChhaarraacctteerriizzaattiioonn ooff IImmppaacctt PPrrooppeerrttiieess ooff FFoorrggeedd,, LLaayyeerreedd,, aanndd AAddddiittiivvee MMaannuuffaaccttuurreedd TTiittaanniiuumm AAllllooyy Melissa Kathryn Matthes University of Nevada, Las Vegas Follow this and additional works at: https://digitalscholarship.unlv.edu/thesesdissertations Part of the Mechanical Engineering Commons RReeppoossiittoorryy CCiittaattiioonn Matthes, Melissa Kathryn, "Characterization of Impact Properties of Forged, Layered, and Additive Manufactured Titanium Alloy" (2016). UNLV Theses, Dissertations, Professional Papers, and Capstones. 2792. http://dx.doi.org/10.34917/9302949 This Thesis is protected by copyright and/or related rights. It has been brought to you by Digital Scholarship@UNLV with permission from the rights-holder(s). You are free to use this Thesis in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/ or on the work itself. This Thesis has been accepted for inclusion in UNLV Theses, Dissertations, Professional Papers, and Capstones by an authorized administrator of Digital Scholarship@UNLV. For more information, please contact [email protected]. CHARACTERIZATION OF IMPACT PROPERTIES OF FORGED, LAYERED, AND ADDITIVE MANUFACTURED TITANIUM ALLOY By Melissa Kathryn Matthes Bachelor of Science – Mechanical Engineering University of Nevada, Las Vegas May 2015 A thesis submitted in partial fulfillment of requirements for the Master of Science in Engineering- Mechanical Engineering Department of Mechanical Engineering Howard R. Hughes College of Engineering The Graduate College University of Nevada, Las Vegas August 2016 Thesis Approval The Graduate College The University of Nevada, Las Vegas August 1, 2016 This thesis prepared by Melissa Matthes entitled Characterization of Impact Properties of Forged, Layered, and Additive Manufactured Titanium Alloy is approved in partial fulfillment of the requirements for the degree of Master of Science in Engineering - Mechanical Engineering Department of Mechanical Engineering Mohamed Trabia, Ph.D. Kathryn Hausbeck Korgan, Ph.D. Examination Committee Co-Chair Graduate College Interim Dean Brendan O’Toole, Ph.D. Examination Committee Co-Chair Jaeyun Moon, Ph.D. Examination Committee Member Robert S. Hixson, Ph.D. Examination Committee Member Moses Karakouzian, Ph.D. Graduate College Faculty Representative ii ABSTRACT CHARACTERIZATION OF IMPACT PROPERTIES OF FORGED, LAYERED, AND ADDITIVE MANUFACTURED TITANIUM ALLOY BY: Melissa Matthes Dr. Mohamed B. Trabia, Examination Committee Chair Associate Dean for Research, Graduate Studies, and Computing Professor of Mechanical Engineering University of Nevada, Las Vegas Dr. Brendan J. O’Toole, Examination Committee Chair Chair, Department of Mechanical Engineering Co-Director, Center for Math, Science and Engineering Education Professor of Mechanical Engineering University of Nevada, Las Vegas New additive manufactured (AM) materials have the potential of optimizing the geometry and microstructure of complex components to enhance their structural integrity while creating them quickly. However, the behavior of AM materials under extreme dynamic loading conditions is not fully understood. This is especially important in many applications. For example, spacecraft components may be impacted by micrometeorites at hyper velocities of multiple kilometers per second, inducing extreme dynamic loading. One type of AM material is created by melting and solidifying metal along a specified path. Depending on the geometry, additional streams will be deposited side-by-side. This process affects the microstructure of the AM part. More voids will exist in a typical AM part as compared to its forged counterpart. While some researchers studied the mechanical iii characteristics of AM metallic components under static and some dynamic loading, no comparable research for behavior under extreme dynamic loading could not be found. The objective of this thesis is to experimentally and computationally study the behavior of titanium alloy, Ti-6Al-4V (Grade 5), under shock loading by comparing forged and layered titanium to the AM titanium. In these experiments, the target materials were subjected to hypervelocity impact using a two-stage light gas gun. A Photonic Doppler Velocimetry (PDV) diagnostics system was used to measure free-surface velocity on the back of each target configuration. The experimental measurements were well documented and can be used to describe the behavior of these materials under shock loading. In addition to velocity measurements, physical damage and spall crack formation were monitored. The experimental measurements were used to validate computational simulations of the experiments. It was determined that AM and forged titanium produce similar velocity profiles during the early stage of impact, with the AM targets exhibiting spall at lower velocities and the multi- layered stacks exhibiting vibrations between plates. Simulations of single layer forged and AM materials provide a good match to experimental data. This study will provide insights into the failure mechanisms of AM titanium under extreme dynamic loading. iv ACKNOWLEDGEMENTS First, I would like to express my very great appreciation to my loving parents and sister for their continued support and patience during the preparation for this final project. I am particularly grateful to Dr. Brendan O’Toole and Dr. Mohammed Trabia for their constructive suggestions during the planning and development of this research work. Especially want to thank them for their willingness to give their time so generously; even when they had a significant amount of other obligations. I want to acknowledge the gas gun lab team Richard Jennings, Eric Bodenchak, and Matthew Boswell for their assistance in gas gun operations. Finally I want to especially thank Dr. Muna Slewa for helping me polish some of my samples. This manuscript has been authored by National Security Technologies, LLC, under Contract No. DE-AC52-06NA25946 with the U.S. Department of Energy and supported by the Site-Directed Research and Development Program. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The U.S. Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan). DOE/NV/25946—2924. I would also like to thank Dr. Cameron Hawkins, Dr. Ed Daykin, Michael Peña, Dr. Robert Hixson, Zach Fussell, Austin Daykin, and Michael Heika for their help and support throughout the project. Finally, I offer my regards and love to my family, my boyfriend, and all of those who supported me in any respect during the completion of the project. v TABLE OF CONTENTS ABSTRACT ................................................................................................................................... iii ACKNOWLEDGEMENTS ............................................................................................................ v TABLE OF CONTENTS ............................................................................................................... vi LIST OF TABLES ......................................................................................................................... ix LIST OF FIGURES ........................................................................................................................ x 1. INTRODUCTION .................................................................................................................. 1 1.1 LITERATURE REVIEW ................................................................................................. 1 1.2 RESEARCH HYPOTHESIS ........................................................................................... 8 1.3 RESEARCH OBJECTIVES ............................................................................................ 9 2. EXPERIMENTAL SETUP ................................................................................................... 11 2.1 UNLV’s TWO-STAGE LIGHT GAS GUN .................................................................. 11 2.1.1 POWDER BREECH AND PUMP TUBE .............................................................. 13 2.1.2 GAS HANDLING SYSTEM .................................................................................. 15 2.1.3 CENTRAL BREECH AND LAUNCH TUBE....................................................... 18 2.1.4 BLAST TANK, DRIFT TUBE, AND TARGET CHAMBER............................... 20 2.2 INSTRUMENTATION .................................................................................................. 23 2.2.1 PROJECTILE VELOCITY MEASUREMENT ..................................................... 23 2.2.2 PHOTONIC DOPPLER VELOCIMETRY (PDV) ................................................ 25 vi 2.3 MATERIALS ................................................................................................................. 27 2.3.1 FORGED TITANIUM ALLOY ............................................................................. 29 2.3.2 EBAM TITANIUM ALLOY .................................................................................. 29 2.4 EXPERIMENTAL SETUP FOR HYPERVELOCITY IMPACT EXPERIMENTS .... 31 2.4.1 TARGET PLATES CONFIGURATIONS ............................................................. 31 2.4.2 TARGET HOLDER CONFIGURATIONS ........................................................... 32 2.5 OPTICAL MICROSCOPY ............................................................................................ 33 3. EXPERIMENTAL RESULTS.............................................................................................. 35 3.1 PHYSICAL OBSERVATIONS ..................................................................................... 35 3.2 MICROSCOPIC RESULTS .......................................................................................... 49 3.3 FREE SURFACE VELOCITY ...................................................................................... 50 4. FINITE ELEMENT ANALYSIS ......................................................................................... 56 4.1 SOFTWARE AND HARDWARE ................................................................................ 56 4.2 SMOOTHED PARTICLE HYDRODYNAMICS (SPH) .............................................. 57 4.3 MODEL DESIGN .......................................................................................................... 57 4.4 JOHNSON-COOK MATERIAL MODEL .................................................................... 59 4.5 MIE-GRÜNEISEN EQUATION OF STATE (EOS) .................................................... 60 4.6 HUGONIOT ELASTIC LIMIT (HEL) AND SPALL STRENGTH ESTIMATION CALCULATION ...................................................................................................................... 62 4.7 SIMULATION DAMAGE RESULTS .......................................................................... 65 vii 4.8 SIMULATION VELOCIMETRY RESULTS ............................................................... 77 5. DISCUSSION ....................................................................................................................... 83 5.1 PHYSICAL CHARACTERISTICS COMPARISON BETWEEN TARGETS ............ 83 5.2 FREE SURFACE VELOCITY PROFILE COMPARISON BETWEEN TARGETS... 84 5.3 LS-DYNA® SIMULATION FREE SURFACE VELOCITY COMPARISON ........... 85 6. CONCLUSIONS AND FUTURE WORK ........................................................................... 86 APPENDIX A. GRAPHICAL REPRESENTATION OF PDV PROBE LOCATIONS ............. 90 APPENDIX B. ALL VELOCITY TRACES .............................................................................. 101 FORGED TITANIUM- 12.7 MM THICK ............................................................................. 101 FORGED TITANIUM-TWO 6.35 MM STACKED PLATES .............................................. 105 FORGED TITANIUM-4 3.2 MM STACKED PLATES ....................................................... 107 ADDTIVELY MANUFACTURE TITANIUM-12.7 MM THICK........................................ 109 APPENDIX C. PARTICLE SPACING STUDY........................................................................ 114 APPENDIX D. SAMPLE LS-DYNA® CODE .......................................................................... 116 REFERENCES ........................................................................................................................... 120 CURRICULUM VITA ............................................................................................................... 126 viii LIST OF TABLES Table 2.1: Typical Chemical Composition of Titanium Alloy (%) Composition by Weight....... 28 Table 2.2: Mechanical Properties of Titanium Alloy ................................................................... 28 Table 2.3: Densities of target materials ........................................................................................ 31 Table 3.1: Deformation results single-layer forged targets .......................................................... 36 Table 3.2: Deformation results two-layer forged targets .............................................................. 36 Table 3.3: Deformation results four-layer plate forged targets..................................................... 37 Table 3.4: Deformation results of AM targets .............................................................................. 37 Table 3.5: Target descriptions, velocity ranges, and probe locations ........................................... 52 Table 4.1: Simulation Dimensions ................................................................................................ 58 Table 4.2: Johnson-Cook Material Properties .............................................................................. 60 Table 4.3: Mie- Grüneisen parameters.......................................................................................... 61 Table 4.4: Forged titanium HEL and spall strength estimation .................................................... 64 Table 4.5: AM 'C' HEL and spall strength estimation ................................................................. 64 Table 4.6: Forged 2-layer HEL and spall strength estimation ...................................................... 64 Table 4.7: Simulation and experimental deformation values for forged titanium alloy ............... 67 Table 4.8: Simulation and experimental deformation values for AM 'C' ..................................... 71 Table 4.9: Experimental and simulation deformation values for layered forged titanium alloy .. 76 ix