Constitutive modeling of flow behavior and microstructure evolution of AA7075 in hot tensile deformation

Hot tensile deformation behavior of AA7075 was studied on a Gleeble-3500 thermal simulation machine. The deformation temperatures were 300 °C, 350 °C, 400 °C, 450 °C, and strain rates were 0.01 s−1, 0.1 s−1, 1 s−1. Electron backscatter diffraction (EBSD) technique was performed on the deformed specimens to investigate the microstructure evolution. The results showed that grain sizes can be refined with increasing deformation amount, temperature, and decreasing strain rate. A constitutive model coupling with the evolution of recrystallization, dislocation, grain size, and damage was established based on the experimental results. The comparisons between model predictions and experimental results were evaluated in terms of statistical methods, the minimum correlation coefficient value was 0.934, and the maximum average absolute relative error and root mean square error were 3.96% and 2.97 MPa, respectively. The results indicated a good prediction accuracy of the model in describing the flow behavior and microstructural evolution of AA7075.