Accurate prediction of nanovoid structures and energetics in bcc metals

TL;DR

This paper introduces a physics-based model for accurately predicting nanovoid structures and energetics in bcc metals, validated by first-principles calculations and experiments, advancing understanding of defect evolution in metals.

Contribution

The study develops a novel, physics-based model that precisely predicts nanovoid structures and energetics, surpassing traditional spherical approximations in bcc metals.

Findings

Stable nanovoid structures can be determined by minimizing Wigner-Seitz area.

A linear relationship exists between formation energy and Wigner-Seitz area.

The model is validated by first-principles calculations and nanovoid annealing experiments.

Abstract

Knowledge on structures and energetics of nanovoids is fundamental to understand defect evolution in metals. Yet there remain no reliable methods able to determine essential structural details or to provide accurate assessment of energetics for general nanovoids. Here, we performed systematic first-principles investigations to examine stable structures and energetics of nanovoids in bcc metals, explicitly demonstrated the stable structures can be precisely determined by minimizing their Wigner-Seitz area, and revealed a linear relationship between formation energy and Wigner-Seitz area of nanovoids. We further developed a new physics-based model to accurately predict stable structures and energetics for arbitrary-sized nanovoids. This model was well validated by first-principles calculations and recent nanovoid annealing experiments, and showed distinct advantages over the widely used spherical approximation. The present work offers mechanistic insights that crucial for understanding nanovoid formation and evolution, being a critical step towards predictive control and prevention of nanovoid related damage processes in structural metals.