Precipitation in AI-Cu-Mg-Ag casting alloy

Abstract

AbstractAbstractCastings made from AI-Cu-Mg-Ag alloys have a high response to hardening in the artificially aged condition. This effect is considered to arise because silver changes the ageing process occurring in the equivalent ternary Al-Cu-Mg alloy and promotes precipitation of thin plates of a monoclinic form of the phase θ(CuAl2) on the {111} matrix planes. Replacing silver with cadmium also causes increased hardening, although the effect is less and arises from a refinement in the size of precipitates formed in the existing ageing process.