Abstract
Grain-boundary sliding may be controlled by the interfacial diffusion of material around boundary inclusions. The sliding or diffusion process leads to a redistribution of local vacancy concentration, and therefore stress, over the surface of the inclusion. In this paper, these stresses are calculated for the case of a rectangular inclusion located symmetrically in the plane of the boundary. The sliding rate is predicted as a function of the aspect ratio of the inclusion and a novel feature, inclusion rotation, is also revealed by the analysis. For small and large aspect ratios, this rotation is minimal but, for ratios close to unity, it can be significant. Rotation is predicted to be zero at a certain critical ratio, when the inclusion experiences only pure shear, with the direction of rotation being reversed at values above and below this critical ratio.
