(323a) Mechanisms of Self Diffusion at Cu-Nb Semicoherent Interfaces

Cu-Nb multilayer nanocomposites exhibit high resistance to radiation damage because Cu-Nb semicoherent interfaces are strong sinks for radiation-induced defects. In this presentation, we describe atomistic modeling studies of the mechanisms by which point defects absorbed at Cu-Nb interfaces diffuse. We find that vacancies and interstitials delocalized on Cu-Nb interface misfit dislocations diffuse in a multi-stage process from one misfit dislocation intersection to another. This mechanism, including the energy along the entire migration path, can be described quantitatively within dislocation theory. Our study suggests that self diffusion in semicoherent heterointerfaces can be predicted from the analysis of the interface structure.