A survey of ab-initio calculations shows that segregation-induced grain boundary embrittlement is predicted by bond-breaking arguments

TL;DR

This survey of ab-initio calculations reveals that solute segregation-induced grain boundary embrittlement in metals can be primarily understood through bond-breaking arguments, with other mechanisms playing secondary roles.

Contribution

It systematically reviews 400 calculations across 77 studies, demonstrating the predictive power of bond-breaking models for grain boundary embrittlement.

Findings

Bond-breaking arguments explain most variation in boundary cohesion changes.

Secondary effects like atomic size and charge transfer are quantitatively assessed.

Robust trend across different crystal structures and computational methods.

Abstract

The segregation of solute atoms to grain boundaries can have a large influence on the mechanical behavior of polycrystals, particularly in metallic alloys. An overview of 400 calculations of solute-induced changes in grain boundary cohesion from 77 separate studies quantitatively demonstrates that the majority of the variation in solute-induced changes in boundary cohesion is explained by simple bond-breaking arguments. This trend is robust to changes in crystal structure and computational methods. The secondary contributions to embrittlement from other mechanisms, such as atomic size effects and charge transfer, are quantified and discussed as well.