First-principles simulations of dislocation cores

In order to understand the chemistry of deformation an adequate description of the strain field near the center of dislocations (the core) is required. We review the development and current status of ab initio methods that have been used to model the core structures of dislocation in elemental refractory metals and intermetallic alloys. Methods employing flexible boundary conditions or dislocation dipoles allow for the direct simulation of dislocations while methods based on the Peierls-Nabarro approximation use the generalized stacking-fault energy to model the restoring force across the lattice discontinuity produced by the dislocation. This energy function can be derived from first-principles reference calculations. In this work we emphasis methods and their application to materials where plastic deformation is complex and Schmids law is violated. (c) 2005 Elsevier B.V. All rights reserved.