A consideration of intergranular fracture caused by trace impurity sodium in an Al–5 wt.%Mg alloy

Abstract

A newly developed model of deformation-induced non-equilibrium grain boundary segregation is used to analyze the intergranular fracture caused by trace impurity sodium in an Al–5 wt.%Mg alloy, which is responsible for a hot ductility trough in the range 150–400 °C. Predictions of sodium grain boundary segregation indicate that a sodium segregation peak corresponds to the ductility trough. It is proposed that the ductility trough is mainly caused by sodium segregation-induced grain boundary embrittlement.