Interface Dislocation Core-Spreading Simulation and Corresponding Response

Abstract

Dislocation can spread its core at an interface especially at a weak shear interface associated with shearing the interface. Such core-spreading dislocation can significantly reduce stress/strain concentration compared with the compact dislocation and thus trap the dislocation in the interface, correspondingly strengthening materials. Employing the Green’s function for a compact dislocation, we derived analytical expressions for the elastic fields of a dislocation with core spreading in anisotropic bimaterials. We proposed a conic model to mimic the spreading core of a dislocation at an interface. The accuracy and efficiency of the conic model are validated by the boundary conditions of both traction and displacement across the interface. Numerical simulation is calculated in the Cu/Nb biomaterial. The results of displacement and stress fields show that: (1) core-spreading dislocation can greatly reduce the stress intensity near the dislocation compared with the dislocation with a condensed core; (2) dislocation core spreading has a great influence on the elastic fields near the core region, while the influence can be negligible when the distance of a field point from the center of the dislocation core is greater than 1.51 times the width of the spreading core; (3) near the core region, Peach-Koehler force induced by the core spreading dislocation is larger than that of the compact dislocation.