Kinetic Monte Carlo study of Al-Mg precipitation

We have performed a kinetic Monte Carlo study of the early stage of the precipitation process in supersaturated Al-Mg, using a model which describes both diffusion and equilibrium properties and is based solely upon first-principles density-functional theory calculations. We have found that the clustering process can be qualitatively affected by the temperature. At a low enough temperature a large abundance of small (on the atomic scale) clusters are quickly formed, while at higher temperatures, one or a few clusters dominate the system. The low temperature clustering could explain the existence of the initial phase, or modulated structure, seen experimentally at lower temperatures.