Seminar: Emmanuelle Marquis, Professor, University of Michigan

It is well known that grain boundaries can migrate as a result of capillary forces, applied external forces, and defect density differences across a grain boundary, as is typically observed during recrystallization and grain growth. It is perhaps less known that grain boundaries can also migrate as the result of solute or defect fluxes, a phenomenon known as diffusion-induced grain boundary migration (or DIGM). Several of our on-going investigations suggest that this phenomenon may be ubiquitous and I will present and discuss observations of DIGM under different conditions. In the case of Ni-Cr alloys during oxidation in air and exposure to molten salts, DIGM can impact the alloy’s oxidation response. Atom probe tomography analyses of alumina scales formed during oxidation of NiAl suggests that DIGM may also be taking place during oxide growth. I will finish with the case of a Fe-Ni-Cr alloy under irradiation, where grain boundary migration is hypothesized to result from point defect diffusion and may be coupling with solute segregation.