Molecular dynamics simulations of helium migration, diffusion behavior of helium bubbles, and melting point of single crystal in bulk γ-Fe

Abstract

The behavior of He atoms in γ-Fe single crystal is studied using the molecular dynamics simulation (MD) methods. Simulations show that the melting point of bulk γ-Fe computed by single-phase and dual-phase methods is 1935 and 1727 ± 1 K, respectively. There is evidence that the diffusion of He clusters is closely related to the cluster size and temperature and at high temperatures (above 1500 K), large clusters will break up into small clusters and quickly separate from the original clusters. The study on the diffusion behaviors of He clusters helps us to better understand the formation of He bubbles and the fusion of two He bubbles. It was confirmed that the He atom can migrate to the subsurface, but it is difficult to escape from the surface and diffuse to the vacuum slab. This work provides useful information for further theoretical and experimental research on the evolution behaviors of He in materials.