Multiple interactions of displacement cascades with He-vacancy clusters were investigated by using molecular dynamics simulations. The effects of a single displacement cascade upon the stability of a He-V cluster depended upon the He/V ratio and the primary knock-on atom energy. The initial He-V clusters consisted of 10 or 20 vacancies, with He/V ratios ranging from 0.2 to 3 and a primary knock-on atom energy of 2 to 10keV. The size of the He-V clusters was found generally to increase with increasing He/V ratio, for the same primary knock-on atom energy, but the stability of the He–V clusters decreased with increasing primary knock-on atom energy. The results were compared with those for voids impacted by collisional cascades. During multiple 5keV cascade events, the final size of the He-V clusters depended upon only the initial He/V ratio. It was noted that the number of vacancies in a He-V cluster was governed by the first cascade event, while subsequent cascade overlap had a significant effect upon its stability. These results were considered in terms of the internal pressure of He-V clusters, the mobility of He atoms, the number of vacancies produced by cascades and the He/V ratio.

Multiple-Interactions of Displacement Cascades with He-Vacancy Clusters in α-Iron - Computer Simulations. L.Yang, X.T.Zu, Z.G.Wang, F.Gao, H.L.Heinisch, R.J.Kurtz, X.Y.Wang, K.Z.Liu: Journal of Nuclear Materials, 2008, 374[3], 437-44