Simulations of grain-boundary migration were presented for systems without impurities, with static impurities and with impurities that were free to diffuse. The simulations were performed within a kinetic Monte Carlo formalism that was based upon a simple spin model with interstitial impurities. The effects of bulk impurity concentration, impurity diffusivity, interaction strength and temperature were considered. Two regimes of motion were identified, at low and high velocities, with a smooth transition between them. Contrary to the classical continuum model of impurity drag, these simulations demonstrated that attractive and repulsive impurity/grain-boundary interactions yielded very different grain-boundary mobilities, and the domain wall velocity never exhibited sharp jumps. A discrete model was developed which described properly the transition between regimes, and the differences between attractive and repulsive impurities.

Grain-Boundary Migration in the Presence of Diffusing Impurities - Simulations and Analytical Models. M.I.Mendelev, D.J.Srolovitz, W.E: Philosophical Magazine A, 2001, 81[9], 2243-69