On the phase separation in nanostructured solid solutions under the effect of a flux of nonequilibrium vacancies

Abstract

The effect of a directional flux of nonequilibrium vacancies in a nanograin of a binary substitutional solid solution is considered for the case of a limited solubility of the components. On the assumption that the initial state is thermodynamically equilibrium and single-phase, an analytical solution for a two-phase problem is given in the regime of quasi-stationary diffusion. An analysis has been performed for solid solutions based on the more mobile and less mobile components for the cases of coherent and incoherent interphase boundaries. The main features of the phase separation have been established, the fractions of the new phases have been estimated, and the distributions of the components and vacancies in the arising phases have been found. The possibility of decreasing nanograin sizes upon the decomposition of the solid solution with a specific distribution of the precipitated phases is demonstrated.