A multiscale and multiphysics framework to simulate radiation damage in nano-crystalline materials

TL;DR

This paper introduces a multiscale, multiphysics framework combining molecular dynamics and atomistic diffusion simulations to study radiation damage in nano-crystalline materials, revealing their self-healing behavior and defect dynamics.

Contribution

The work presents a novel integrated framework for simulating radiation effects in nano-crystalline materials, capturing defect evolution and self-healing mechanisms over multiple scales.

Findings

Nano-crystalline materials generate fewer defects than single crystals during radiation.

Intergranular absorption of interstitials promotes self-healing in nano-crystals.

Approximately 50% of vacancies remain due to stable vacancy clusters.

Abstract

This work presents a multiscale and multiphysics framework to investigate the radiation-induced damage in nano-crystalline materials. The framework combines two methodologies, including molecular dynamics simulations with electronic effects and long-term atomistic diffusion simulations in nano-crystalline materials. Using this framework, we investigated nano-crystalline materials' self-healing behavior under radiation events. We found that the number of defects generated in nano-crystals during the cascade simulations was less than in single crystals. This behavior was due to the fast absorption of interstitial atoms in the grain boundary network during the cascade simulations, while vacancies migrated to the boundaries in a much longer time scale than interstitial atoms. Thus, nano-crystalline materials showed a self-healing behavior where the number and size of the defects are drastically reduced with time. We found that the self-healing behavior of nano-crystalline materials is limited, and about 50% of vacancies survived. This effect resulted from clusters of vacancies' collective behavior, which are much more stable than individual vacancies.