Hot tensile deformation study and constitutive modeling of new high zinc containing hot rolled Al–Zn–Mg–Cu alloy

Abstract

Hot tensile deformation behavior of a new kind of hot rolled high zinc containing Al-9.6%Zn-3.1% Mg-1.84%Cu alloy was investigated under different deformation temperatures (250°C-400°C) and strain rates (0.000 05-000 05 s −1 ) conditions. From the true stress-true strain diagrams, it is observed that peak stress decreases with increasing temperature and decreasing strain rate. Exponent type equations following Arrhenius model were used to predict peak stress at the experimental conditions and the values were compared with the experimental values. Zener-Hollomon parameter (Z) has been determined at various test conditions and activation energy has been found to be 146.2 kJ mol −1 which is slightly greater than the bulk self-diffusion energy of pure Al (142 kJ mol −1 ) and consistent with the previous findings. Microstructural analysis of the deformed samples shows that deformation mechanism transforms to dynamic recrystallization from dynamic recovery with the decrease of the Z value. Additional XRD, SEM, DSC and EDS analysis were performed to determine the type of the precipitates present in the sample before deformation and analyze their effect on the deformation mechanism.