Grain-boundary sliding could be controlled by the interfacial diffusion of material around boundary inclusions. The sliding or diffusion process led to a redistribution of local vacancy concentrations, and therefore stress, over the surface of the inclusion. These stresses were calculated for the case of a rectangular inclusion located symmetrically in the plane of the boundary. The sliding rate was predicted as a function of the aspect ratio of the inclusion and a novel feature, inclusion rotation, was also revealed by the analysis. For small and large aspect ratios, this rotation was minimal but, for ratios close to unity, it could be significant. Rotation was predicted to be zero at a certain critical ratio, where the inclusion experienced only pure shear, with the direction of rotation being reversed at values above and below this critical ratio.

Interfacial Stresses at Inclusions during Grain-Boundary Sliding. B.Burton: Philosophical Magazine A, 2002, 82[11], 2303-20