Dependence of simulated radiation damage on crystal structure and atomic misfit in metals

TL;DR

This paper explores how crystal structure and atomic misfit influence radiation damage in metals, using molecular dynamics simulations to compare Fe, CrCoNi, and a hypothetical single-atom metal, revealing differences in defect concentrations and damage mechanisms.

Contribution

It introduces a comparative simulation study of radiation damage across different metal structures, highlighting the impact of atomic misfit and crystal structure on defect formation and recombination.

Findings

CrCoNi sustains higher dislocation densities than Fe and A-atom systems.

CrCoNi exhibits more stacking faults than the A-atom system.

Vacancy and interstitial concentrations are higher in CrCoNi, indicating different defect dynamics.

Abstract

This study investigates radiation damage in three metals in the low temperature and high radiant flux regime using molecular dynamics and a Frenkel pair accumulation method to simulate up to $2.0$ displacements per atom. The metals considered include Fe, equiatomic CrCoNi, and a fictitious metal with identical bulk properties to the CrCoNi composed of a single atom type referred to as an A-atom. CrCoNi is found to sustain higher concentrations of dislocations than either the Fe or A-atom systems and more stacking faults than the A-atom system. The results suggest that the concentration of vacancies and interstitials are substantially higher for the CrCoNi than the A-atom system, perhaps reflecting that the recombination radius is smaller in CrCoNi due to the roughened potential energy landscape. A model that partitions the major contributions from defects to the stored energy is described, and serves to highlight a general need for higher fidelity approaches to point defect identification.