The hot deformation behavior and constitutive analysis of AA7085 aluminum alloy based on the uncorrected and corrected flow stress for deformation heating and friction were investigated by hot compressive tests. The results show that deformation heating has more significant influence on the flow stress than that of friction. Two constitutive equations with and without deformation heating and friction could properly describe the hot deformation behavior of the material. However, the revised constitutive model to describe the hot deformation of AA7085 aluminum alloy taking account of deformation heating and friction is proposed at high strain rate, which gives the values of correlation coefficient and average absolute relative error are 0.989 and 4.86%, respectively.

Because of the tensile strength decreasing of the friction stir welded wrought magnesium (Mg) alloy compared to the base material, the reasons for the failure of weld has been focused on. After the fracture in transverse tension, the crack went through the welded joint from the center of the weld to the transition zone between the thermal-mechanical affected zone and weld zone. In the present study, the microstructure characteristics and its effect on the facture in the triple junction region is investigated. Based on the metallography and the electron back-scattered diffraction (EBSD) technology, it was observed that a twin band extended from the triple junction region to the middle of weld. The profuse twinning in the twin band was considered to play an important role on the crack propagation from the stir zone edge to the crown zone.