A molecular dynamics study of helium diffusion and clustering in fcc nickel

Abstract

Helium diffusion and clustering in nickel are studied by molecular dynamics simulations. Extensive atomistic simulations are performed using a modified analytic embedded-atom model. We find that the rate of helium clustering increases with increasing temperature, and interstitial helium clusters can create nickel interstitials when they reach sufficient size and temperature is higher than 600K. Finally, the mobility of helium clusters is also investigated using trajectory time decomposition method. The diffusion properties of He clusters with 1–3 helium atoms are found to obey the Arrhenius relationship over the whole temperature range considered while He clusters with 4 helium atoms show an non-Arrhenius relationship at higher temperatures.