Defect structure near edge dislocations in neutron-irradiated Cu—0.3 at.%Ge

Abstract

Cu—0.3 at.%Ge bulk specimens were irradiated with 14 MeV fusion neutrons at 473 K. Dislocation loops were formed on one side of preexisting edge dislocations, whereas they were hardly formed in the dislocation-free matrix. A neutron irradiated sample was subsequently irradiated with 1 MeV electrons in a high voltage electron microscope. The behavior of the edge dislocation and the dislocation loops was simultaneously examined by in situ observation. The large dislocation loops of more than about 8 nm grew, while the smaller loops shrank and disappeared, and the dislocation loops were identified to be of interstitial type. The edge dislocation climbed toward the group of the dislocation loops. It was found that the loops were formed at the side of dilatation strain field of the edge dislocation. The direct effect of the cascade on the preferential nucleation and growth of the dislocation loops in the vicinity of edge dislocation was discussed.