Jeffrey M. Rickman

Dr. Jeffrey Rickman earned his Ph.D. in Physics from Carnegie Mellon University and joined Lehigh University in 1993 after postdoctoral appointments at the University of Michigan and Argonne National Laboratory. He holds a joint appointment in the Departments of Physics and Materials Science and Engineering, and has received the Class of ’61 Professorship. Dr. Rickman has received several honors including the Young Investigator Award from the National Science Foundation and the Chambers Junior Professorship and the Culler Prize (Miami University).  He is a Fellow of ASM International and Fellow of the American Ceramic Society.

Title: Interfacial transitions at grain boundaries

Abstract: The presence of interfaces can have a dramatic effect on phase behavior in materials.  In this talk, I first describe experimental evidence for interfacial phase (complexion) transitions with an emphasis on binary alloys.  After reviewing the state of the field, I will describe the results of Monte Carlo simulations of complexion transitions using both simplified lattice models and off-lattice semi-grand-canonical Monte Carlo simulations.  The focus will be on the development of complexion diagrams that highlight the richness of the phase-like behavior of systems with boundaries and, in particular, underline a series of first-order transitions and associated critical points.  I will also describe the impact of these transitions on grain-boundary kinetics (i.e., boundary mobility) and the Kapitza resistance of grain boundaries using atomistic simulation, with application to phonon engineering.  Finally, I will describe some recent results linking complexion transitions with abnormal grain growth as summarized by interfacial time-temperature-transformation (TTT) diagrams that are useful for materials processing.