Physics Colloquium: “Development of Materials for Extreme Environments”

Nasr Ghoniem

UCLA, Mechanical & Aerospace Engineering Department

Abstract: Extreme-environment materials present some of the most significant challenges to the development of many advanced technologies in the nuclear, aviation, space, defense, automotive, and power generation industries. Such materials are subject to unprecedented assaults of high thermal heat flux, plasma and nuclear interactions, extremely fast mechanical loads, erosion and corrosion, to mention a few examples. To meet these challenges, material development must integrate detailed models of the mechanical behavior, together with advanced mechanical design strategies. To accomplish this goal, a multiscale modelling process will be described, where a “top-down” approach is developed that allows incorporation of materials microstructure, and hence manufacturing information, into successively more detailed representations. At the macroscopic level, continuum mechanics is used to couple elasticity and elasto-plasticity, while at the mesoscale, microstructure- informed crystal plasticity and discrete fracture mechanics are used, while at the nano- and micro- scales, the method of Discrete Dislocation Dynamics completely resolves the materials microstructure. To endow this multiscale strategy with relevant design attributes, it is embedded within Multiphysics FEM-based simulations of coupled fluid mechanics, heat transfer, and structural mechanics. Three illustrative examples of the Multiscale-Multiphysics approach will be presented for the development of: (1) Plasma-Facing structures in fusion energy; (2) Extreme temperature heat exchangers (recuperators) for hybrid aviation, and (3) the Leading Edge of hypersonic vehicles.

Biography: Nasr Ghoniem is a “distinguished professor” in the departments of Mechanical and Aerospace Engineering, with joint appointment in the Materials Science & Engineering Department at UCLA. He has wide experience in the development of materials in extreme environments (Nuclear, Mechanical and Aerospace), and has developed some of the most widely-used multiscale computational methods for studies of defect physics and mechanics. He is a fellow of the American Nuclear Society, the American Academy of Mechanics, the American Society of Mechanical Engineers, the Japan Society for Promotion of Science, and The Materials Research Society. He was the general chair of the Second International Multiscale Materials Modeling Conference in 2004 and is the chair of the 19th International Conference on Fusion Reactor Materials in 2019. He serves on the editorial boards of several journals, and has published over 350 articles, 10 edited books, and is the co-author of a two- volume book (Oxford Press) on the mechanics and physics of defects, computational materials science, radiation interaction with materials, instabilities and self-organization in non-equilibrium materials (Oxford Press, 2007, 1100 pages.) He graduated 37 Ph.D. students and 25 post-doctoral scholars (15 are currently in faculty positions). His current research on “Materials in Extreme Environments” is supported by the National Science Foundation, the U.S. Department of Energy, ARPA-E, and the US Air Force Office for Scientific Research.

THIS WILL BE AN ONLINE EVENT.

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