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.