Direct atomistic modeling of solute drag by moving grain boundaries

TL;DR

This paper demonstrates that molecular dynamics simulations can effectively model solute drag by moving grain boundaries, capturing atomic-scale interactions and diffusion effects that influence material properties.

Contribution

It introduces a novel MD simulation approach to study solute drag by grain boundaries, revealing atomic-level mechanisms of diffusion and vacancy interactions.

Findings

MD simulations reproduce solute drag effects.

Moving GBs activate diffusion and alter local order.

Vacancy atmospheres are dragged by moving GBs, accelerating diffusion.

Abstract

We show that molecular dynamics (MD) simulations are capable of reproducing the drag of solute segregation atmospheres by moving grain boundaries (GBs). Although lattice diffusion is frozen out on the MD timescale, the accelerated GB diffusion provides enough atomic mobility to allow the segregated atoms to follow the moving GB. This finding opens the possibility of studying the solute drag effect with atomic precision using the MD approach. We demonstrate that a moving GB activates diffusion and alters the short-range order in the lattice regions swept during its motion. It is also shown that a moving GB drags an atmosphere of non-equilibrium vacancies, which accelerate diffusion in surrounding lattice regions.