Probing the hydrogen movement in Zr-Cu amorphous alloys using molecular dynamics simulations

Zr-based amorphous alloys, showing hydrogen permeance comparable to pure crystalline Pd, are prospective candidates for replacing the current Pd-based hydrogen selective membranes. There have been a lot of theoretical studies about the diffusion mechanism in their amorphous structures. But most of them have provided only just phenomenological understanding because of staying on works with qualitative approximations. To overcome this situation and get more realistic insight about the hydrogen movement in amorphous metals, we adopted atomistic modeling which gives directly quantitative information about nanoscale phenomena. In order to perform such an atomistic simulation, interatomic potentials for the Zr-H and Cu-H binary systems had to be developed based on the second nearest-neighbor modified embedded-atom method_(2NN MEAM) formalism. A few first-principles calculations of physical properties for the Cu-H binary system were carried out to supplement data which are necessary to optimize the potential parameters. The developing potentials in this study will be able to reasonably reproduce fundamental physical properties (structural, thermodynamic, defect and diffusion properties). Finally we are going to perform diffusion simulations for each amorphous and crystalline Zr-Cu alloy of same composition, and obtain quantitative results about the difference between them.