The glide of screw dislocations in bcc Fe: Atomistic static and dynamic simulations

We present atomic-scale simulations of screw dislocation glide in bcc iron. Using two interatomic potentials that, respectively, predict degenerate and non-degenerate core structures, we compute the static 0 K dependence of the screw dislocation Peierls stress on crystal orientation and show strong boundary condition effects related to the generation of non-glide stress components. At finite temperatures we show that, with a non-degenerate core, glide by nucleation/propagation of kink-pairs in a {110} glide plane is obtained at low temperatures. A transition in the twinning region, towards an average {112} glide plane, with the formation of debris loops is observed at higher temperatures. (c) 2006 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.