Helium-vacancy cluster in a single bcc iron crystal lattice

The properties of the cluster HenV, an iron vacancy with an increasing number of He atoms, is studied with molecular statics and molecular dynamics simulations. A study of the binding energy of the self-interstitial atom (SIA) and the He, shows that from n = 6 the HenV cluster is stable and cannot shrink anymore, and from n = 16 the HenV2 cluster is stabilized by the emission of SIA in the form of a < 110 > dumbbell. Calculation of the pressure exercised by the HenV cluster shows local peak normal stress and shear stress values up to 9 GPa and 4 GPa, respectively. The local configurations of HenV suggest that with increasing helium content, a high symmetry configuration close to a face centered cubic lattice is formed.