Influence of heat treatment on the microstructural evolution of Al-3 wt.% Cu during high-pressure torsion

Solution-treated, peak-aged and overaged samples of the model alloy Al-3 wt.% Cu, obtained by selective heat treatments of the pre-material, have been subjected to high-pressure torsion at room temperature and at 200 degrees C. The mechanical behaviour of the samples was investigated with torque measurements during deformation and microhardness measurements after deformation. Irrespective of the initial material condition, in the saturation regime a comparable equilibrium microstructure was found consisting of ultrafine aluminium grains stabilized by precipitates formed at grain boundaries.