Mechanical Aspects of High Entropy Alloys

Dr. Weidong Li obtained his B.S. in Materials Science and Engineering from China University of Geoscience (Beijing) in 2007, M.S. in Materials Processing Engineering from University of Science and Technology Beijing in 2010, and Ph.D. in Materials Science and Engineering from University of Tennessee in 2013. He has been serving the Department of Materials Science and Engineering at the University of Tennessee as an adjunct faculty member since 2018. Furthermore, he has nearly ten-year industrial experience, working in R&D units of the ceramic, rubber and tire, and aerospace industries on a variety of topics. His research interests generally lie in the alloy design, integrated computational materials engineering (ICME), fracture and fatigue, and mechanical behavior of materials, specifically in materials like high-entropy alloys, superalloys, and specialty steels. Dr. Jamieson Brechtl obtained his B.S. in Nuclear Engineering and his M.S. in Nuclear Engineering and Engineering Physics from the University of Wisconsin, Madison, in 2012. He later obtained his Ph.D. in Energy Science and Engineering from the University of Tennessee, Knoxville, in 2019. Currently, he works as a Postdoctoral Research Associate in the Multifunctional Equipment Integration Group at the Oak Ridge National Laboratory. His research interests include plastic deformation, irradiation effects, nanoindentation, X-ray and neutron diffraction, microscopy, high-entropy alloys, and bulk-metallic glasses. He has authored or co-authored over thirty journal papers and presented at numerous engineering conferences. He was awarded the Chancellor’s Citation for Extraordinary Professional Promise from the University of Tennessee in 2019. He is also a current member of The Minerals, Metals and Materials Society (TMS). Dr. Peter K. Liaw graduated from the Chiayi High School, obtained his B.S. in Physics from the National Tsing Hua University, Taiwan, and his Ph.D. in Materials Science and Engineering from Northwestern University, USA, in 1980. After working at the Westinghouse Research and Development (R&D) Center for thirteen years, he joined the faculty and becomes an Endowed Ivan Racheff Chair of Excellence in the Department of Materials Science and Engineering at The University of Tennessee (UT), Knoxville, since March 1993. He has been working in the areas of fatigue, fracture, nondestructive evaluation, and life-prediction methodologies of structural alloys and composites. Since joining UT, his research interests include mechanical behavior, high-entropy alloys, bulk-metallic glasses, nondestructive evaluation, biomaterials, and processing of high-temperature alloys and ceramic-matrix composites and coatings with the kind and great help of his colleagues at UT and the nearby Oak Ridge National Laboratory, as well as throughout the world. He has published over one-thousand journal papers, edited twenty books, and presented numerous plenary, keynote, and invited talks at various national and international conferences. He was awarded the Royal E. Cabell Fellowship at Northwestern University. He is a recipient of numerous “Outstanding Performance” awards from the Westinghouse R&D Center. He was the Chairman of The Minerals, Metals and Materials Society (TMS) “Mechanical Metallurgy” Committee, and the Chairman of the American Society for Metals (ASM) “Flow and Fracture” Committee. He has been the Chairman and Member of the TMS Award Committee on “Application to Practice, Educator, and Leadership Awards.” He is a Fellow of ASM, MRS, and TMS. He has been given the Outstanding Teacher Award, the Moses E. and Mayme Brooks Distinguished Professor Award, the Engineering Research Fellow Award, the National Alumni Association Distinguished Service Professor Award, the L. R. Hesler Award, and the John Fisher Professorship at UT, and the TMS Distinguished Service Award. He has been the Director of the National Science Foundation (NSF) Integrative Graduate Education and Research Training (IGERT) Program, the Director of the NSF International Materials Institutes (IMI) Program, and the Director of the NSF Major Research Instrumentation (MRI) Program at UT.

• Part 1. Introduction1. A historical sketch2. Definitions3. Classifications4. Thermodynamics5. Chemistries6. Microstructures7. Distinctive characteristics compared to conventional alloys8. Current status and trendPart 2. Mechanistic design approach9. Empirical design10. Mechanism-based design11. Application-driven design12. Computation-aided design13. Machine learning assisted design14. High-throughput experimentation15. High-throughput computation16. Comparison with tranditional alloys17. Summary and outlookPart 3. Microstructure18. Phase structures19. Grain structures20. Grain boundaries21. Dislocation characters and dynamics22. Twins23. Stacking faults24. Precipitates25. Short range order26. Heterogeneities27. Comparison with traditional alloys28. Summary and outlookPart 4. Strength and ductility29. Composition effect30. Processing effect31. Microstructure effect32. Temperature effect33. Strength-ductility trade-off34. Strategies to overcome trength-ductility trade-off35. Comparison with traditional alloys36. Summary and outlookPart 5. Deformation mechanisms37. Yielding behavior38. Dislocation-mediated deformation39. Twinning-mediated deformation40. Stacking-fault-mediated deformation41. Martensitic-transformation-mediated deformation42. Grain-size effects43. Strain rate and temperature effects44. Role of chemical heterogeneities45. Role of short-range ordering46. Synergistic-deformation mechanisms47. Comparison with traditional alloys48. Summary and outlookPart 6. Strengthening mechanisms49. Lattice distortion50. Solid-solution strengthening51. Dislocation strengthening52. Grain-boundary strengthening53. Precipitation strengthening54. Twin-boundary strengthening55. Phase-transformation strengthening56. Short-range-order strengthening57. Comparison with traditional alloys58. Summary and outlookPart 7. Serrated plastic flow59. Factors affecting serration behavior60. Link between micro-mechanisms and macroscopic properties61. Theoretical modeling62. Experimental studies63. Comparison with traditional alloys64. Summary and outlookPart 8. Creep65. Creep characterization66. Creep mechanisms67. Influencing factors68. Comparison with tranditional alloys69. Summary and future workPart 9. Fracture70. Fracture-toughness characterization71. Fracture toughness72. Fractography73. Fracture toughness – fractography correlation74. Fracture mechanisms75. Comparison with tranditional alloys76. Summary and outlook77. Fatigue78. Low-cycle fatigue79. High-cycle fatigue80. Fatigue-crack-growth rate81. Fatigue mechanisms82. Comparisons with tranditional alloys83. Summary and outlookPart 1.1 Small-scale mechanical behaviors84. Nano- and micro-pillar compression85. Nanoindentation86. Small-scale deformation mechanisms87. Comparison with bulk counterparts88. Comparison with traditional alloys89. Summary and outlookPart 12. Potential applications90. Structural applications91. Functional applications92. Current endeavors toward applications93. Assessment on tranditional alloy replacement94. Summary and outlookPart 13. Future directionsPart 14. Conclusions