Phase separation in nanocrystalline alloys upon generation of nonequilibrium vacancies at grain boundaries

Abstract

The problem of the formation of a zone of phase separation in a nanograin is considered under conditions of generation of nonequilibrium vacancies at grain boundaries. Two time-spatial scales have been revealed, which characterize (i) the anomalous diffusion of the alloy components responsible for the appearance of a relatively narrow near-boundary region with a changed concentration of the alloy components and (ii) the normal-diffusion region extending through much larger distances from the boundary. The main features of the spatial distribution of the concentrational inhomogeneity near the boundary is analyzed.