Alloy Stabilization of Nanocrystals: Why Does it Work?

Published: January 31st, 2017

Category: Upcoming Events

Hosted by Dr. Simon Phillpot

Department of Materials Science and Engineering Seminar Series

Tuesday, January 31, 2017  – 4:05 – 4:55 p.m. – Florida Gym 270

 

Speaker:

Dr. Stephen M. Foiles

Distinguished Member of Technical Staff

Computational Materials and Data Science Department

Sandia National Laboratories

 

Title:

Alloy Stabilization of Nanocrystals: Why Does it Work?

Abstract:

Nanocrystalline metals with grain sizes less than ~100 nm are of great interest due to their attractive mechanical properties compared to conventional grain scale counterparts.  However, the highly non-equilibrium nature of these metals leads to instability to grain growth and thus the loss of the desirable properties.  Several studies have shown that the nanocrystalline grain size can be stabilized by appropriate alloying.  Multiple mechanism for this stabilization have been proposed including thermodynamic arguments based on the reduction of grain boundary energy due to segregation and kinetic arguments based on particle pinning or the modification of grain boundary mobility due to alloy segregation.  This talk will discuss on-going efforts to employ a variety of simulation and experimental approaches to help unravel the relative role of these influences in model alloy systems.

 

Bio-Sketch:

Stephen Foiles is a Distinguished Member of Technical Staff at Sandia National Laboratories in the Computational Materials and Data Science department.  He received a BS in Physics from Stanford University in 1978 and a PhD in Theoretical Physics from Cornell University in 1983.   After graduation, he joined the technical staff at Sandia first at the CA site and later transferred to the NM site.  His research focuses on the development and application of atomic-scale simulation methodologies to the study of defects and interfaces.  He is a Fellow of the Institute of Physics and the American Physical Society, co-recipient of the 2016 Journal of Materials Science Cahn Prize and the recipient of the 2017 TMS Cyril Stanley Smith Award.