Dynamic material model (DMM) was employed to survey the effect of Al2O3 nanoparticles addition on hot workability of AA 7075, in comparison with the conventional AA 7075 alloy. Samples were deformed in the temperature range of 350-500 °C and strain rates of 0.005-0.5 s-1. In order to indicate the safe temperature and strain rate zones for hot working of AA 7075 alloy and AA 7075/Al2O3 nanocomposite, hot deformation processing maps of the materials were achieved according to the microstructural evaluations and the corresponding calculations. The value of Q for AA 7075/Al2O3 nanocomposite was obtained 288 kJ/mol, which was considerably higher than that of AA 7075. The discrepancy in thermal conductivity and elastic module of ceramic content and base matrix might impair some hot working conditions which result in failure in unstable domains. The suitable experimental circumstances for hot deformation of AA 7075/Al2O3 nanocomposite were located in the temperature range of 440-500 °C and strain rates lower than 0.03 s-1. Microscopic studies confirmed the occurrence of adiabatic shear banding and flow localization in the unstable region.

Keywords