Competing processes in reactions between an edge dislocation and dislocation loops in a body-centred cubic metal

Molecular dynamics simulation was used to investigate reactions of a 1/2 < 1 1 1 >{1 1 0} edge dislocation with interstitial dislocation loops of 1/2 < 1 1 1 > and < 1 0 0 > type in a model of iron. Whether loops are strong or weak obstacles depends not only on loop size and type, but also on temperature and dislocation velocity. These parameters determine whether a loop is absorbed on the dislocation or left behind as it glides away. Absorption requires glide of a reaction segment over the loop surface and cross-slip of dipole dislocation arms attached to the ends of the segment: these mechanisms depend on temperature and strain rate, as discussed here. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.