A TEM investigation on the effect of semisolid forming on precipitation processes in an Al–Mg–Si Alloy

A thixoformed 6082 aluminum alloy was subjected to microstructural study using electron microscopy techniques. Thixocast bars and a component of complex shape were investigated. The effect of heat treatment (T6, solution treatment and artificial aging, and T8, solution treatment, cold rolling, and artificial aging) was studied in terms of hardness and precipitation sequence. In particular, T8 treatment had a threefold hardening effect compared with T6. The role of the eutectic and the aging response of the α globules were studied. The precipitation sequence within the globules was found similar to the one of wrought Al–Mg–Si alloy, while the precipitation phenomena within the eutectic followed different kinetics.