Self-interstitial atom clusters as obstacles to glide of 1/3 〈1 1 2̄ 0〉 {1 1̄ 0 0} edge dislocations in α-zirconium

Atomic-scale details of interaction of a 1/3 〈1 1 2̄ 0〉 {1 1̄ 0 0} edge dislocation with clusters of self-interstitial atoms (SIAs) in α-zirconium has been studied by computer simulation. Four typical clusters are considered. A triangular cluster of five SIAs lying within a basal plane bisected by the dislocation glide plane is not absorbed by the dislocation but acts as a moderately strong obstacle. A 3-D SIA cluster lying across the glide plane is completely absorbed by the dislocation by creation of super-jogs, and is a weak obstacle. Interaction of the dislocation with glissile SIA loops with perfect Burgers vector inclined at 60° to the dislocation glide plane shows that the process depends on the vector orientation. Defects of the two orientations are strong obstacles, and one, which initially forms a sessile segment on the dislocation line, is particularly so.