Design Kinetic Parameters for Improved Resilience of Materials under Irradiation

TL;DR

This paper proposes a design framework for high entropy alloys with enhanced radiation resistance by optimizing defect properties to promote defect recombination, supported by theoretical, simulation, and experimental evidence.

Contribution

It introduces a novel set of criteria based on defect diffusion and migration energies to guide the design of radiation-resistant HEAs, reducing reliance on extensive experiments.

Findings

Optimal defect recombination occurs when vacancy and interstitial diffusion coefficients are similar.

V- and Cr-based alloys show improved radiation resistance under the proposed criteria.

Experimental results support the theoretical and simulation-based design approach.

Abstract

High entropy alloys (HEAs) have captured much attention in recent years due to their conceivably improved radiation resistance compared to pure metals and traditional alloys. However, among HEAs, there are millions of design possibilities considering all potential compositions. In this study, we develop criteria to design HEAs with improved radiation resilience taking into consideration defect properties to promote interstitial-vacancy recombination. First, we conduct rate theory calculations on defects followed by molecular dynamics (MD) simulations on pure W and W-based multicomponent concentrated alloys. It is found that when the diffusion coefficients for single vacancies and interstitials become similar and the effective migration energies of defects is minimum (maximum diffusivities), defect recombination becomes optimal, and the concentration of defects is significantly reduced. This is supported by MD simulations indicating improved radiation resistance of V- and Cr-based alloys, which satisfy the above-stated criteria. Furthermore, experimental observations also reinforce the proposed approach. This study sheds light on the design criteria for improved radiation resistance and helps material selection without the need of extensive experimental work.