PNNL

Abstract

The interaction of helium-vacancy (He-V) clusters with a gliding a/2{110} edge dislocation in a-Fe is investigated by molecular dynamics methods under a constant strain rate at temperatures of 100 to 600 K. A number of small HenVm (n/m = 0~4) clusters initially placed at different positions relative to the slip plane are comparatively studied. The results show that the interaction of He-V clusters with gliding edge dislocations depends on the helium-to-vacancy (He/V) ratio, the position of the clusters relative to the slip plane, the cluster size, and also temperature. The obstacle strength of the He-V clusters relevant to the dislocation motion generally increases with increasing He/V ratio at the same temperature, but decreases slightly with increasing temperature for the same He-V cluster. One of the interesting results is that He-V clusters do not move along with the dislocation, even at 600 K.