On the effect of solute atoms on grain-boundary migration

Abstract
A model for solute-dependent grain-boundary migration in a dilute binary alloy is proposed. It is assumed that the mobility across the grain boundary may be different for solute and matrix atoms. Even if there is no interaction energy between the solute atoms and the grain boundary, a concentration profile is shown to develop when the boundary is acted upon by a driving force. If the mobility of solute atoms across the boundary is less than that of the matrix atoms, a pile-up of solute in front of the growing grain results. This pile-up exerts a drag on the boundary. Breakaway from the solute profile is discussed.