Effects of deformation temperature and strain-rate on workability of a rapidly solidified hypereutectic Al-Si P/M alloy

The flow stress and ductility of an aluminum P/M alloy prepared by hot extrusion from rapidly solidified powders of an Al-20Si-5Fe-2Cu-1Mg-1Mn alloy were investigated by compression and tensile tests to clarify its workability. Flow stress decreases and critical amount of strain for deformation without cracking increases with deformation temperature. The increase in strain rates increases flow stress at a higher temperature than 180°C. In compression test, the relation between flow stress σ and strain rate ε is described as σ=Kεm. The strain sensitivity exponent, m increases with deformation temperature and becomes about 0.3 at 480°C. A nomograph useful to predict the flow stress at a certain ram speed and temperature has been made.