Molecular Dynamics Simulation of Ga Penetration along Grain Boundaries in Al: a Dislocation Climb Mechanism

TL;DR

This paper uses molecular dynamics simulations to uncover the dislocation climb mechanism behind gallium penetration along grain boundaries in aluminum, providing a new model that aligns with experimental observations.

Contribution

It introduces a novel dislocation climb-based model for Ga penetration in Al grain boundaries validated by simulations and experiments.

Findings

Dislocation climb is the key mechanism for Ga penetration.

The new model accurately predicts penetration behavior.

Simulation results agree with experimental data.

Abstract

Many systems where a liquid metal is in contact with a polycrystalline solid exhibit deep liquid grooves where the grain boundary meets the solid-liquid interface. For example, liquid Ga quickly penetrates deep into grain boundaries in Al, leading to intergranular fracture under very small stresses. We report on a series of molecular dynamics simulations of liquid Ga in contact with an Al bicrystal. We identify the mechanism for liquid metal embrittlement, develop a new model for it, and show that is in excellent agreement with both simulation and experimental data.