Characterization of an Al–Cu cast alloy

A type A206 Al–Cu alloy was cast in a mould that forces a solidification gradient to study its effect on the microstructure and solidification reactions taking place in the material. These reactions were detected and identified by means of thermal analyses of the cooling curves. The microstructure of the material was assessed by measuring the secondary dendrite arm spacing (DAS), grain size and porosity. It was found that these three parameters increased as the average solidification rate decreased. Thermal analysis showed that the temperatures for liquidus, solidus and solvus were affected by the solidification rate, although the two former ones to a lesser extend. The occurrence of a complex eutectic was detected when the rate of solidification was reduced.