First principles study on the segregation of metallic solutes and non-metallic impurities in Cu grain boundary

TL;DR

This study uses Density Functional Theory to analyze how metallic and non-metallic impurities segregate at copper grain boundaries, affecting material strength and embrittlement, providing insights for alloy design.

Contribution

It provides a first-principles computational analysis of impurity segregation energies in copper grain boundaries, highlighting elements that strengthen or weaken the material.

Findings

V, Zr, and Ag may enhance strength

O, S, F, and P tend to weaken the boundary

Local distortion correlates with weakening effect

Abstract

Metallic dopants have the potential to increase the mechanical strength of polycrystalline metals. These elements are expected to aggregate in regions of lower coordination, such as grain boundaries. At the grain boundaries, they can have a beneficial (toughening) or detrimental effect (e.g. grain boundary embrittlement). In this study, we employ Density Functional Theory (DFT) to compute the segregation energies of various metallic and other non-metallic elements to determine their effect when introduced in a symmetric Cu grain boundary. The study results may be used to qualitatively rank the beneficial effect of certain metallic elements, such as V, Zr, and Ag, as well as the strong weakening effect of non-metallic impurities like O, S, F and P. Furthermore, the induced local distortion is found to be proportional to the weakening effect of the elements.