Microstructure and High Temperature Deformation of Extruded Al-12Si-3Cu-Based Alloy

The high temperature deformation behavior of commercial Al-12Si-3Cu-2Ni-1Mg alloy (DM104™) which was fabricated by casting and subsequent hot extrusion was evaluated by compressive tests over the temperature range of 250–470 °C and strain rate range of 0.001–1/s. The extruded alloy had equiaxed grains, spherical Si particles and fine intermetallic phases, such as δ(Al3NiCu) and Q(Al5Cu2Mg3Si6). The true stress-true strain curves from the compressive tests exhibited steady-state flow after reaching the peak stress. A close relationship between the steady-state stress and a constitutive equation for high temperature deformation was observed. Fine equiaxed grains and a dislocation structure within the equiaxed grains were observed in the deformed specimens, suggesting the occurrence of dynamic recrystallization during high temperature deformation