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

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.