Flow stress equation for hot compression deformation of Al-Mg-Si alloy

In order to provide the theoretical basis for the establishment and optimization of technological parameters for hot working process,the flow stress behavior of the Al-Mg-Si alloy containing Zr element during hot compression deformation was studied with Gleeble-1500 thermal-mechanical simulator at temperatures from 653 K to 803 K and deformation rates from 0.01 s-1 to 1 s-1.In additon,a mathematical model for the flow stress of material deformation was established with regression method.The results show that the alloy is a material sensitive to normal strain rate,and the obvious steady-state rheological feature exists on the true stress-true strain curves.With increasing the deformation rate and decreasing the deformation temperature,the flow stress increases.The true stress-true strain curves are dynamic recovery curves at lower deformation tempertures,and are dynamic recrystallization curves at higher deformation temperatures.The flow stress σ of the alloy can be described by the Zener-Hollomon parameter including Arrhenius term,where the values of parameters A,α and n are 1.89×1010 s-1,0.024 MPa-1 and 7.46 respectively.Moreover,the activation energy Q for the hot deformation is 166.85 kJ/mol.