Microstructure evolution of cast Al-Si-Cu alloys in solution treatment

To develop a software to predict the evolution of microstructure and the development of mechanical properties during the heat treatment of cast aluminum alloys, we modeled the redistribution of solute during the solution treatment of multicomponent alloys. The predictions of solidification simulation software or the results of experiment provided the initial microstructure and solute distribution for simulation of heat treatment. Binary through quinary aluminum alloys with silicon, copper, magnesium, and iron were modeled. The basic model assumed local equilibrium (no undercooling due to nucleation or growth) and computed diffusion in the solid constituents during solidification. The evolution of microstructure during solution treatment was followed by qualitative and quantitative metallography. The results of simulation for the ternary alloy Al-7%Si-3.5%Cu were compared to experimental observation.