An Abnormal Size Effect of Interaction between Nanovoids and Dislocations in Irradiated Materials

Abstract

The interactions between the gliding dislocations and irradiation-induced nanovoids are explored by means of molecular simulation in this paper. An abnormal phenomena is found that a gliding full dislocation could be repelled or blocked by nanovoids in copper and nickel crystals when its size is small enough (d<3nm), which is different from the conventional view that voids always attracted the dislocations. Besides, we find that the configuration of the nanovoids is most likely spherical when its size is less than 2nm, while it becomes tetrahedral or polyhedral. The new finding implies the irradiated materials could be strengthened by the irradiation-induced nanovoids at the initial stage of irradiation and provides a new insight to the role of the nanovoids in the irradiated materials.