High-throughput computing for hydrogen transport properties in ε-ZrH2

In the zirconium-based composites, the transport properties of hydrogen atoms directly affect the precipitation process of the epsilon-ZrH2 phase. Therefore, the mechanism behind this phenomenon was explored by applying first-principle calculations based on the density functional theory (DFT). For the first time, the diffusion model of hydrogen (H) in the body-centered tetragonal (BCT) structure of epsilon-ZrH2 was established. The high-throughput calculation results show that the diffusion coefficient is greatly affected by high temperatures. The pressure changes the structure to tetragonal distortion and increases the energy barrier of diffusion and decreases the diffusion coefficient. Y and Gd atoms have a repulsive effect on hydrogen atoms; this will increase the activation energy and diffusion coefficient and reduce the mobility of hydrogen atoms. The solute elements Cr, Fe, Nb, and Si increase the diffusion coefficient, while Ti, Ni, Y, Pt, and Gd decrease. These influence trends are closely related to the atomic radius by Spearman correlation coefficients analysis. This research provides a reference for the design of nuclear material cladding.

Automated summary

In this study, the mechanism behind the effect of hydrogen atom transport properties on the precipitation process of ε-ZrH2 phase in zirconium-based composites was explored using density functional theory calculations. The diffusion model of hydrogen in the body-centered tetragonal structure of ε-ZrH2 was established, and the high-throughput calculation results showed that the diffusion coefficient is greatly affected by high temperatures. Various solute elements and pressure were found to have either increasing or decreasing effects on the diffusion coefficient, which were closely related to atomic radius.