Effect of cooperative grain boundary sliding and migration on dislocation emission from interface collinear crack tip in nanocrystalline bi-materials

The theoretical model of an edge dislocation near interface collinear crack tips in nanocrystalline bi-materials with cooperative grain boundary sliding and migration is formulated. As a typical example, we focus on analyzing the effect of two disclination dipoles produced by cooperative grain boundary sliding and migration on an edge dislocation emitting from a finite interfacial crack tip in nanocrystalline bi-materials. The dislocation force and the critical stress intensity factors for an edge dislocation emitting from an interface collinear crack tip under remote plane loadings are derived by using the complex potential method. And the influences of grain size, disclination strength, migration distance, sliding distance and interface crack length on the critical stress intensity factors are discussed in detail. It can be found that the effect of cooperative grain boundary sliding and migration deformation on the dislocation emission from interface collinear crack tip lies in the crack length, the dislocation emission angle, and the strength of the cooperative deformation itself.