Effect of Interfacial Structural Phase Transitions on the Coupled Motion of Grain Boundaries: A Molecular Dynamics Study

TL;DR

This molecular dynamics study reveals how interfacial structural phase transitions in grain boundaries significantly influence their coupled motion, shear strength, and microstructural evolution in copper.

Contribution

It demonstrates the profound impact of interfacial phase transitions on grain boundary behavior, including coupling factors and shear strength variations.

Findings

Different phases exhibit distinct coupling factors with varying magnitudes and signs.

Shear strength differs by up to 40% between phases at low temperatures.

Phase transitions strongly affect microstructural evolution kinetics.

Abstract

In this work the coupled motion of two different phases of {\Sigma}5(210)[001] grain boundaries were investigated by molecular dynamics simulations of fcc Cu. The effect of interfacial structural phase transitions is shown to have a profound effect on both the shear strength and the nature of the coupled motion. Specifically, the motion of the two different phases is described by ideal coupling factors {\beta}<100> and {\beta}<110> that have different magnitudes and even signs. Additionally, the shear strength for the two inter- facial phases is observed to differ by up to 40 % at the lowest temperatures simulated. The study demonstrates that grain boundary phases transitions may have strong effects on the kinetics of microstructural evolution.