Dr. Lin Li, Associate Professor in School for Enginnering of Matter, Transport and Energy at Arizona State University, Tempa will give a seminar titled "Machine Learning Enhanced Multiscale Material Mechanics Models for Complex Alloys" to the interested faculty and students at Discovery Park.

Abstract

Complex alloys, including both structurally disordered metallic glass and chemically disordered high entropy alloys, have received considerable attention because they provide a broad range of opportunities for property control, and have found applications in structural materials, damage resistance, and many other functionalities. The development of the predictive materials mechanics model is challenging due to the complex atomic environments and non-equilibrium state of matters that are dynamically evolving. For the structural disorder alloys, I will present a multiscale material mechanics model, incorporating atomic-level disordered features in a coarse-grained model that enables collective deformation and macroscopic mechanical behaviors to be modeled in the metallic glasses. Machine learning models have been used to parameterize atomic flow defects to inform the coarse-grained model. Emphasis will be placed on the influence of nanoscale heterogeneity due to the atomic short-range to medium-range orders on the large-scale shear banding behaviors. For the chemical disorder alloys, I will focus on high entropy alloys (HEAs) that are formed by mixing equal or relatively large portions of multiple elements. Both experimental and computational evidence suggest the existence of preferred atomic pairs or chemical ordering in many HEAs. We have developed a machine learning potential in the following hybrid molecular dynamics/Monte Carlo simulations to elucidate the complicated interplay between local ordering, phase stability, dislocation behaviors, mechanical properties in model NbMoTaW HEAs. The approach with machine learning-enhanced multiscale material mechanics models can accelerate the design and discovery of high-performance structural materials in a vast configurational and compositional space.

Bio

Dr. Lin Li is currently an associate professor in the School for Engineering of Matter, Transport, and Energy at Arizona State University (ASU). Dr. Li received her Ph.D. degree in Materials Science and Engineering from The Ohio State University in 2011. Thereafter, she worked as a postdoctoral associate at the Massachusetts Institute of Technology. Prior to her current position at ASU, Dr. Li held the roles of assistant professor and tenured associate professor at the University of Alabama. Her research interest is structure-property-processing relationships in advanced structural metals and materials for extreme environments, with emphasis on size effect, structural disorder, interfaces, and mechanics. Her research utilizes multiscale modeling and experimentation, statistical tools, and machine learning models to establish the connections between microscopic atomic processes and macroscopic material performance, particularly for nanostructured alloys, metallic glasses, and high entropy alloys. Dr. Li is the recipient of the Ralph E. Powe Junior Faculty Enhancement Award from Oak Ridge Associated Universities, and the Air Force Summer Faculty Fellowship. Her research has been sponsored by the National Science Foundation (NSF), the Department of Energy (DOE), and the National Aeronautics and Space Administration (NASA).