Combination of Continuum and Atomistic Approaches for the Study of Dislocation Nucleation from Atomic Size Surface Defects

Abstract

ABSTRACTAtomistic simulations realized on an f.c.c. crystal containing atomic size surface defects (step and groove) show that the defects are privileged sites for dislocation nucleation. Before nucleation, an elastic shear, precursor of the dislocation, appears in the plane in zone with the step where the dislocation will be nucleated. In order to explain the strong localization of the localized elastic precursor shear, we have analyzed the stress concentration near the surface defects using the continuum point force approach. For the step case, the origin of the localized shear is related to an increase in the interplanar separation due to the stress concentration.