Mechanical properties of a heat treated particle reinforced thixocast composite

The casting of metal matrix composites in the semisolid state is especially advantageous compared with conventional casting, as the presence of the primary solidified phase prevents the ceramic particles from agglomeration. Bars of a particle reinforced thixo-cast 357 aluminium alloy composite were heat treated in T5 and T6 conditions. Electrical conductivity and hardness measurements were performed on aged samples to follow the precipitation process. T6 condition produces slightly higher hardness peaks and enhancing kinetics of precipitation due to super-saturation. After ageing, a set of samples were prepared for tensile testing to study the effect of T6 heat treatments on mechanical properties. Yield strength and ultimate tensile strength show a similar trend as a function of time at constant temperature. Ultimate tensile strength decreases with increasing elongation. A comparison with mechanical data of the matrix is also reported.