Resistance of refractory high-entropy alloys to ultrafast laser irradiation

TL;DR

This study models the response of refractory high-entropy alloys to ultrafast laser irradiation, revealing their high radiation resistance and unique atomic diffusion behaviors, which could inform the development of more durable materials.

Contribution

It provides the first detailed modeling of ultrafast laser effects on refractory high-entropy alloys using a hybrid computational approach.

Findings

Refractory alloys do not show nonthermal melting up to ~10 eV/atom.

Heavy-element high-entropy alloys are more radiation resistant than lighter-element alloys.

Damage involves Ti atom diffusion, forming a superionic-like state.

Abstract

Response of refractory high-entropy alloys MoNbTaVW and HfNbTaTiZr to ultrafast laser radiation is modelled with the hybrid code XTANT-3, combining tight-binding molecular dynamics with the transport Monte Carlo and Boltzmann equation. A two-temperature state with elevated electronic temperature and a cold atomic lattice is studied. The parameters of the electronic system in such a state are evaluated: electronic heat capacity, thermal conductivity, and electron-phonon coupling parameter with the electronic temperatures up to ~25,000 K. It is also demonstrated that the two refractory alloys do not show signs of nonthermal melting up to the deposited doses of ~10 eV/atom, making them more radiation resistant than the Cantor alloy or stainless steel. These results suggest that heavy-element high-entropy alloys are more radiation resistant than those containing only lighter elements. Damage in irradiated HfNbTaTiZr starts with the selective diffusion of Ti atoms, forming a transient superionic-like state.