Dr. David Srolovitz - Grain boundary dynamics: a unifying, mechanistic view
Tuesday, September 10, 2019 at 4:00pm to 5:00pm
Building 1, 190
33 MASSACHUSETTS AVE, Cambridge, MA 02139
This talk is part of a 3-day mini-summit through DMSE. Please join us on Sept. 11 and 12 for more events!
Abstract: Grain boundaries (GB) show a wide range of dynamic phenomena including migration, shear-coupled motion, sliding, roughening, and defect absorption. Most of our understanding of these is phenomenological—with distinct theories for each. This presentation attempts to unify many of these phenomena into a single description based on the same microscopic mechanism: the motion of disconnections.
Disconnections are line defects that are constrained to the GB and have both dislocation and step character. The set of possible disconnection, Burgers vectors, and step heights is established by crystallography, their thermodynamics are determined by elasticity, bonding and GB structure, and their relative importance by statistical mechanical considerations. I will present a combination of molecular dynamics and kinetic Monte Carlo simulations with theoretical analyses to clarify and (as often as possible) make quantitative predictions of a wide-range of GB Page 2 of 3 properties and their temperature dependencies.