报告题目：Deviation from High-Entropy Configurations in the Atomic Distributions of a Multi-principal-element Alloy
主讲人：Peter K. Liaw 教授
The alloy-design strategy of combining multiple elements in near-equimolar ratios has shown great potential for producing exceptional engineering materials, often known as “high-entropy alloys”. Understanding the elemental distributions, and, thus, the evolution of the configurational entropy during solidification, are the goal of the present research. The case of the Al1.3CoCrCuFeNi model alloy is examined, using integrated theoretical and experimental techniques, such asab initiomolecular-dynamics simulations, in-situ neutron levitation and scattering experiments, synchrotron X-ray diffraction, high-resolution electron microscopy, and atom-probe tomography. It is shown that even when the material undergoes elemental segregation, precipitation, chemical ordering, and spinodal decomposition, a significant amount of disorder remains, due to the distributions of multiple elements in the major phases. The results suggest that the high-entropy-alloy-design strategy may be used to develop a wide range of complex materials, which are not limited to single-phase solid solutions. The integrated experimental and theoretical techniques, discussed here, are particularly well-suited to studying partially-ordered materials, produced using the high-entropy-alloy design strategy.
Prof.Peter K. Liaw graduated from the National Tsing Hua University (Taiwan) and obtained his Ph.D. in Northwestern University, USA, in 1980. After working at the Westinghouse Research and Development (R&D) Center for thirteen years, he joins 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 1993. His research interests include mechanical behavior, nondestructive evaluation, biomaterials, high-temperature alloys, bulk metallic glasses, high-entropy alloys, ceramic-matrix composites and coatings with the kindest and greatest help of his colleagues at UT and the near-by Oak Ridge National Laboratory. He has published seven hundred and eighty-six journal papers, edited more than thirty books, and presented numerous keynote and invited lectures at various national and international conferences, universities, and industries.He was the Chairman of the TMS (The Minerals, Metals and Materials Society) "Mechanical Metallurgy" Committee, and the Chairman of the ASM (American Society for Metals) "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. 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.