Effect of Ag and Zr solutes on dislocation emission from the {\Sigma}11(332)[110] symmetric tilt grain boundary in fcc Cu

TL;DR

This study uses atomistic simulations to explore how different solutes, especially those with smaller size mismatches, influence dislocation nucleation at grain boundaries in nanocrystalline copper, aiming to improve material stability.

Contribution

It reveals the dependence of solute effects on their distribution and size mismatch, providing insights for optimizing solute additions to enhance nanocrystalline material stability.

Findings

Smaller size mismatch solutes more effectively suppress dislocation emission.

Solute distribution at grain boundaries critically influences dislocation nucleation.

Optimal solute selection can stabilize nanocrystalline copper against grain growth.

Abstract

Addition of solutes is commonly used to stabilize nanocrystalline materials against grain growth. However, segregating at grain boundaries, these solutes also affect the process of dislocation nucleation from grain boundaries under applied stress. Using atomistic simulations we demonstrate that the effect of solutes on the dislocation nucleation strongly depends on the distribution of solutes at the grain boundary, which can vary dramatically depending on the solute type. In particular, our results indicate that the solutes with a smaller size mismatch can be more effective in suppressing dislocation emission from grain boundaries. Bearing in mind that dislocation slip originating from grain boundaries or their triple junctions is the dominant mechanism of plastic deformation when grain sizes are reduced to the nanoscale, we emphasize the importance of the search for the optimal solute additions, which would stabilize the nanocrystalline material against grain growth and, at the same time, effectively suppress the dislocation nucleation from the grain boundaries.