Texture dependence of hydrogen diffusion in nanocrystalline nickel by atomistic simulations

Atomistic simulations were performed to highlight the importance of the texture on the diffusion of hydrogen atoms in nanocrystalline nickel. Significant anisotropic diffusion is observed in longitudinal and through thickness directions. Our results show that the diffusion coefficient of hydrogen atoms through thickness in [001] textured nickel is larger than those values obtained for [011] and [111]. The diffusivity along longitudinal and transverse directions in [111] textured samples is found to be higher than that along thickness direction. Additionally, it is determined that the presence of hydrogen atoms changes the vacancy formation of the substrate and the vacancy defects are responsible for the anisotropy of hydrogen diffusion. These findings improve our understanding of hydrogen diffusivity at the atomistic level for hydrogen storage in the materials.