A molecular dynamics technique was used to calculate the formation energies of small HenVm clusters using the embedded atom method, the Baskes-Melius potential and the Lennard-Jones potential to describe the interactions of Al-Al, Al-He and He-He, respectively. The binding energies of an interstitial He atom, an isolated vacancy and a self-interstitial Al atom to a HenVm cluster were obtained from the calculated formation energies of the clusters. All of the binding energies depended mainly upon the He-vacancy ratio (n/m) of clusters rather than upon the cluster size. The binding energies of a He atom and an Al atom to a HenVm cluster decreased with the ratio, but the binding energy of a vacancy to a HenVm cluster increased with the ratio. The results showed that He atoms could increase the binding energy of a vacancy to a HenVm cluster, and decreased the binding energies of a He atom and an Al atom to the cluster. This, the He atom acted as a catalyst for the formation of HenVm clusters.

Atomistic Behavior of Helium–Vacancy Clusters in Aluminium. B.Y.Ao, J.Y.Yang, X.L.Wang, W.Y.Hu: Journal of Nuclear Materials, 2006, 350[1], 83-8