Molecular Dynamics Study of Self-Diffusion in Zr

TL;DR

This study uses molecular dynamics with a semi-empirical potential to analyze self-diffusion mechanisms in zirconium's hcp and bcc phases, revealing different dominant diffusion pathways and comparing results with experimental data.

Contribution

It introduces a direct MD-based method for determining defect concentrations and diffusion mechanisms in Zr, improving understanding of phase-specific diffusion behaviors.

Findings

Interstitial diffusion dominates in hcp Zr.

Both vacancy and interstitial mechanisms contribute in bcc Zr.

Results agree well with experiments at high temperatures.

Abstract

We employed a recently developed semi-empirical Zr potential to determine the diffusivities in the hcp and bcc Zr via molecular dynamics simulation. The point defect concentration was determined directly from MD simulation rather than from theoretical methods using T=0 calculations. We found that the diffusion proceeds via the interstitial mechanism in the hcp Zr and both the vacancy and interstitial mechanisms give contribution in diffusivity in the bcc Zr. The agreement with the experimental data is excellent for the hcp Zr and for the bcc Zr it is rather good at high temperatures but there is a considerable disagreement at low temperatures.