A Non ! Local Formulation of the Peierls Dislocation Model

Cohesive zone models provide an illuminating and tractable way to include constitutive non!linearity into continuum models of defects[ Powerful insights have been gained by studying both dislocations and cracks using such analyses[ Recent work has shown that as a result of the locality assumption present in such cohesive zone models\ signi_cant errors can be made in the treatment of defect energies[ This paper aims to construct a non!local version of the PeierlsÐNabarro model in which the atomic level stresses induced at the slip plane depend in a non!local way on the slip degrees of freedom[ Our results should be seen as a demonstration in principle of how microscopic calculations can be used to construct insights into consti! tutive nonlocality[ The non!local interplanar kernel used here is computed directly from atomistics and is used to evaluate both the structure and energetics of planar dislocations[ The non!local formulation does not signi_cantly change the dislocation core structure from that obtained with the local model\ but the new formulation leads to signi_cant improvements in the description of dislocation energetics for dislocations with planar cores[ Þ 0887 Elsevier Science Ltd[ All rights reserved[