Segregation-induced embrittlement of grain boundaries

Abstract

Conditions are discussed under which an interface, possibly containing an adsorbed species, is capable of sustaining an atomistically sharp cleavage crack, rather than having any such crack blunt out via dislocation nucleation. Two models for ductile versus brittle interface response are discussed. One of these is applied to model grain boundaries in face-centred-cubic materials, and is used to compare predictions with experimental observations on the embrittlement of Cu polycrystals by the addition of dilute concentrations of Bi. The results are in qualitative agreement.