Clustering and Dissolution of Small Helium Clusters in Bulk Tungsten

Density functional theory calculations are conducted to investigate the stability and interactions among small helium (He) clusters in bulk tungsten (W). The lowest energy structure of each cluster for sizes n=1 to 6 is determined. With the formation of He clusters, He defects form in bulk W. The thermodynamics of the clusters are investigated in the temperature range of 1000–2300 K using molecular dynamics. This study provides the information essential to understand small He cluster behavior in bulk W.