A novel precipitation kinetics model for fast-aging process of Al–Zn–Mg–Cu alloy

In this paper, a set of novel thermo-mechanical coupling kinetics models were developed for the fast aging process of Al–Zn–Mg–Cu alloy. The precipitates models in this paper described the continuous growth behavior of precipitates in the two-step aging, by introducing temperature dependent constants, the contribution of each aging step in the two-step aging process was quantitatively characterized; the analytical formula for the critical temperature of instantaneous nucleation during the aging process was derived; providing a pre-aging time threshold in the competition mechanism, which for the inhibition of precipitates nucleation on dislocations in secondary aging. Subsequently, associated above models with macroscopic material strength, the yield strength of 7075 aluminum alloy after fast aging was predicted. Through the quantitative verification by mechanical properties experiments, the model values have a good agreement with the experimental ones, and the errors are below 8%.