Vacancy-Mediated Phase Separation of Binary Alloy

Abstract

The most important element process of the phase separation of binary alloys is the vacancy diffusion mechanism. A set of phenomenological dynamical equations for the vacancy-mediated phase separation is formulated from a mean-field free energy and the numerical simulation of the model is performed. From numerical results, vacancies form clusters along phase boundaries between two degenerate stable domains. The width of the vacancy-cluster across the interface grows with the logarithmic function of time. If effects of vacancy-clusters are not dominant, the dynamics is not different from that by the exchange dynamics. If the effects are dominant, the characteristic length proportional to the average domain size grows with the logarithmic function of time. The analytical approach shows that the logarithmic growth of the characteristic length is related to the growth law of the width of the vacancy-cluster.