Influence of electropulsing stress aging on electric conductivity, mechanical properties, and microstructure of the AA7150 Al alloy

In the present study, the effect of electropulsing stress aging (ESA) on the electric conductivity, mechanical properties, and microstructure of the AA7150 aluminum (Al) alloys are studied. Experiments are carried out in this regard and obtained results show that as the ESA time increases, the electrical conductivity increases and the strength decreases. Furthermore, the electrical conductivity and ductility of the ESA samples are higher and the strength is lower than that for samples with conventional stress aging (CSA) at the same stress aging time. The evolution of microstructure is analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and transmission electron microscope (TEM). The results indicate that the volume fraction of ƞ phase increase with the extension of ESA time. Moreover, it is found that ESA accelerates the formation and growth of ƞ phase. The results of fractography demonstrate that when the as-received samples are treated by ESA, the size and depth of dimples of the ESA samples decrease and the elongation all declines. This study provides the theoretical basis for predicting the electrical conductivity and mechanical properties in electropulsing assisted stress age forming.