A three-dimensional atomistic kinetic Monte Carlo study of dynamic solute-interface interaction

摘要

A three-dimensional atomistic Kinetic Monte Carlo (aKMC) model was developed and used to study the interaction between mobile solutes and a migrating interface. While the model was developed with a simplified energetic and topological description, it was also constructed to capture, in the absence of solute, the Burke-Turnbull model for interface migration and, in the presence of solutes, solute segregation to different types of interface sites. After parameterizing the model, simulations were performed to study the relationship between average interface velocity and imposed driving pressure for varying solute concentration and solute diffusivity. Despite significant differences in the underlying assumptions of numerical and analytical solute drag models, the latter was found to be a phenomenological tool that adequately captures the trends observed by the aKMC simulations (e.g. the effect of solute concentration on solute drag pressure). One trend that could not be adequately explained was the observed dependence of maximum drag pressure on solute diffusivity. This effect is attributed to the coupling between the structure of a migrating interface and the ability for solute to remain segregated to the interface.