Cavity nucleation in single-component homogeneous amorphous solids under negative pressure

TL;DR

This study uses molecular dynamics simulations to analyze cavity nucleation in amorphous metallic solids under negative pressure, revealing activation-type behavior consistent with classical nucleation theory.

Contribution

It introduces a novel cavity identification method and demonstrates that cavity formation follows classical nucleation theory in amorphous metals.

Findings

Cavity formation is an activation process.

Activation energy and critical size are comparable to crystal nucleation.

Cavity nucleation can be described by classical nucleation theory.

Abstract

Understanding the cavity formation and cavity growth mechanisms in solids has fundamental and applied importance for the correct determination of their exploitation capabilities and mechanical characteristics. In this work, we present the molecular dynamics simulation results for the process of homogeneous formation of nanosized cavities in a single-component amorphous metallic alloy. To identify cavities of various shapes and sizes, an original method has been developed, which is based on filling cavities by virtual particles (balls) of the same diameter. By means of the mean first-passage time analysis, it was shown that the cavity formation in an amorphous metallic melt is the activation-type process. This process can be described in terms of the classical nucleation theory, which is usually applied to the case of first order phase transitions. Activation energy, critical size and nucleation rate of cavities are calculated, the values of which are comparable with those for the case of crystal nucleation in amorphous systems.