Molecular statics calculations were used to evaluate the formation energies and binding energies of He-vacancy clusters in, and near to, the core of an a/2<111>{110} edge dislocation in α-Fe, using empirical potentials. The formation energies of these He-V clusters, and their binding energies to the dislocation, depended upon the He-to-vacancy ratio of the clusters. For a ratio which was equal to, or greater than, unity the He-vacancy clusters had negative binding energies on the compression side of the dislocation and a strong positive binding energy on the tension side. However, for ratios of less than unity, the He-V clusters had a positive binding energy on both sides near to the dislocation core. On the slip plane, the binding energies of the He-V clusters to the dislocation depended not only upon the He-to-vacancy ratio, but also the cluster size.

Interaction of Helium–Vacancy Clusters with Edge Dislocations in α-Fe. L.Yang, X.T.Zu, Z.G.Wang, F.Gao, X.Y.Wang, H.L.Heinisch, R.J.Kurtz: Nuclear Instruments and Methods in Physics Research B, 2007, 265[2], 541-6