In-Situ TEM Observation of Dislocation Interaction with Cavity in Ion-Irradiated Pure Vanadium during Tensile Test

摘要

To investigate the hardening mechanism due to cavity formation in vanadium, in-situ transmission electron microscopy (TEM) observation was performed for the helium ion-irradiated pure vanadium during tensile test. The obstacle barrier strength α was calculated from the bow-out dislocation based on line tension model and the obstacle barrier strength of cavity in pure vanadium was about 0.5 to 0.7 and slightly increased with increasing the cavity size. Generations of cross-slip and double cross-slip occurred with jog generating after the interaction between dislocations and cavities. The fraction of cross-slip and double cross-slip at dislocation pinning were increased with the increasing cavity size and it is suggested that the cross-slip of dislocation can be formed at cavity due to local climb motion of dislocation on the cavity surface.