The effect of nickel content on the fracture behaviour of Cu-Al-Niβ-phase alloys

Abstract

The fracture behaviour of Cu-14 wt% Al alloys has been studied as a function of nickel content varying from 0 to 10 wt%. It was found that the presence of a brittle phaseγ2 at the grain boundaries is responsible for intergranular fracture in low nickel alloys. Severe intergranular embrittlement exhibited by high nickel alloys in not associated with any precipitate at the grain boundaries. In fact when high nickel alloys are cooled slowly, a ductile phase (α) forms along the grain boundaries that resists the propagation of crack through grain boundaries and the fracture is transgranular.