Dislocation models of interfacial shearing induced by an approaching lattice glide dislocation

Abstract

When a lattice glide dislocation approaches a bi-metal interface with relatively low shear strength, it causes the interface to shear. Interfacial shearing is accommodated by the nucleation and growth of interfacial dislocations, which have an attractive interaction with the incoming dislocation. Thus a critical length scale exists at which the net force on the incoming lattice glide dislocation can transition from being initially repulsive to attractive. In this paper, we develop dislocation-based interface shear models in order to represent this mechanism of interface/dislocation interaction at the continuum scale. Three versions are devised with different degrees of complexity and hence computational cost: the continuous shear model (CSM), simplified-CSM model (SCSM), and single dislocation shear model (SDSM). We simulate the interaction processes with these three models by means of a Green’s function method for an anisotropic bimaterial. All three models find that the critical length scale at which the dislocation becomes attracted to the interface increases as the interfacial shear resistance decreases. While the most complex model of the three, the CSM, performs the best, the SCSM and SDSM are more advantageous for implementation into higher-length scale dislocation dynamics models.