Effects of precipitated helium, deuterium or alloy elements on glissile motion of dislocation loops in Fe–9Cr–2W ferritic alloy

Abstract

The effects of precipitated deuterium, helium, and solute elements on the thermal stability of dislocation loops associated with the glissile motion in the Fe–9Cr–2W ferritic alloy have been studied by in situ TEM observations performed during the post-annealing of the specimens irradiated with the ions of these materials or high-energy electrons. It has been found that dislocation loops formed by helium ion irradiation survive even at higher temperatures, which indicate pinning effects of helium bubbles on dislocation loops. In contrast, the dislocation loops formed by deuterium ion irradiation exhibit 1-D glide motion and disappear at comparatively lower temperatures than those in the case of the loops formed by electrons irradiation. It is suggested that the loops could start to glide owing to reducible effects of precipitated deuterium atoms on the precipitation of alloy elements on the loop dislocations, which was accompanied by the removal of precipitated deuterium from loop dislocations.