Dislocation Core Structure Evolution During Dislocation Glide in FCC Lattices

Abstract

A dislocation core model is developed in terms of a singular decomposition of the elastic field surrounding the defect in a power series of 1/rⁿ. The decomposition is a Laurent expansion beginning with the term corresponding to the Volterra dislocation and continuing with a series of dipoles and multipoles. The analysis is performed for an edge dislocation in an fcc lattice. The field surrounding the dislocation is derived by means of atomistic simulations. The coefficients of the series expansion are determined from the elastic field using path independent integrals. When loaded by a shear stress smaller than the Peierls stress, the core distorts. The distortion up to the instability (Peierls stress) is monitored based on the variation of these coefficients. The stacking fault separating the two partials is characterized, by using a similar procedure, as a source of elastic field.