Monte Carlo simulations of the decomposition of metastable solid solutions: Transient and steady-state nucleation kinetics

Abstract

We present a study on the kinetics of coherent precipitation in weakly super-saturated substitutional solid solutions by the Monte Carlo method. Our simulations are based on a simple atomistic model of diffusion by vacancy jumps. The whole precipitation process (from early stages to late stage coarsening) is followed for various supersaturations and temperatures, and typical behaviors observed in the simulations are compared to those predicted by the classical theories. Special emphasis is placed on the first stages of the decomposition (incubation and nucleation) and on the effects of the vacancy diffusion mechanism. Finally we consider the addition of a third (impurity) element, which can be used to control the kinetic pathway: such effects are quantitatively explored with the Monte Carlo method.