Flow stress behavior of high-purity Al-Cu-Mg alloy and microstructure evolution

The flow stress behavior of high-purity Al-Cu-Mg alloy under hot deformation conditions was studied by Gleeble-1500, with the deformation temperature range from 300 to 500 degrees C and the strain rate range from 0.01 to 10 s(-1). From the true stress-true strain curve, the flow stress increases with the increasing of strain and tends to be constant after a peak value, showing dynamic recover, and the peak value of flow stress increases with the decreasing of deformation temperature and the increasing of strain rate. When the strain rate is 10 s(-1) and the deformation temperature is higher than 400 degrees C, the flow stress shows dynamic recrystallization characteristic. TEM micrographs were used to reveal the evolution of microstructures. According to the processing map at true strain of 0.7, the feasible deformation conditions are high strain rate (>0.5 s(-1)) or 440-500 degrees C and 0.01-0.02 s(-1).