Abstract: The hot deformation behaviors and microstructures of Al-Zn-Mg-Cu-Cr aluminum alloy during hot deformation have been studied using thermal stimulation test, optical microscopy and transmission electron microscopy. As a result, the true stress vs. true strain cures and the microstructures of various deformation conditions are obtained; the microstructures gradually incline to dynamic-recrystallization with the deformation temperature rising and the recrystallization grains refine with the decrease of deformation temperature or with raising the strain rates; the quantitative relationship between the Zener-Hollomon parameter (Z) and average recrystallization grain size in the subsequent heat treatment is set up.

Key words: Al-Zn-Mg-Cu-Cr aluminum alloy, Hot deformation, The true stress vs. true strain cures, Microstructures