MSE Seminar: Fundamental Mechanisms Governing Plastic Deformation and Failure in Extreme Environments - A Tale of Two Types of Metals

Calit2 Auditorium
Penghui Cao

Department of Mechanical and Aerospace Engineering
Department of Materials Science and Engineering
UC Irvine

Abstract: A more fundamental understanding of materials behavior under complex conditions is required in many important applications, such as renewable energy and aerospace systems. However, our mechanistic understanding of material failure is impeded by the complexity of the environment, and by the limitation of diagnostic methods. In this talk, I will present a mesoscale modeling method of metadynamics simulation as well as mechanisms governing mechanical behaviors of two different types of materials, metallic glasses and crystalline metals subjected to extreme conditions. I will first discuss long time-scale metadynamics simulations of deformation and flow in metallic glasses, which reveal clear details of atomic-level deformation and diffusion as the elementary processes that control the stress and temperature dependence of amorphous plasticity. The second part of the talk will demonstrate how crystalline metals respond to energetic flux and thermomechanical extremes. Using computational modeling and in situ experiments, several designs of damage-tolerant structural materials from composition to nanotexture will be discussed, including single-phase alloys, nanograined metals and CNT-aluminum composite. Finally, a perspective of an environmentally dependent potential energy landscape unifying these examples and implications to other scientific problems will be discussed.

Bio: Penghui Cao is an assistant professor in the Department of Mechanical and Aerospace Engineering at UCI. Prior to this, he was a postdoctoral associate at Massachusetts Institute of Technology after obtaining his doctorate from Boston University in 2014. His research involves developing microscopic modeling algorithms to probe the mechanisms controlling microscale deformation and failure of materials. His research interests lie in the fundamental understanding of rate-dependent plastic deformation and flow in the context of computational materials modeling, with applications to advanced materials technology.