Abstract
It is shown that at temperatures and migration rates where the volume diffusion ahead of the migrating grain boundary is important the inhomogeneity of the solute distribution ahead of the migrating boundary contributes strongly to the total Gibbs energy of the solid solution. Corresponding corrections to the Gibbs energy of the bulk alloy in the vicinity of the grain boundary appear already in the first term of the series expansion on the concentration gradient powers. The comparative analysis of the gradient and coherency strain driving forces for the diffusion induced grain boundary migration is given (considered for Ni/Cu system).