Effect of shot peening treatment on Corrosion behaviors of friction stir welded joint of 7075 aluminum alloys

摘要

The corrosion behaviors of friction stir welded (FSW) joint of 7075 aluminum alloy with and without shot peening treatment (SPT) were investigated by method of acid salt spray. The macroscopical and microscopical corrosion features were observed by using of optical microscope and scanning electron microscope, respectively. The results show that the specimen with the SPT exhibit better resistance to the corrosion than that of specimen without the SPT under salt spray exposure for 60 hours. However, the differences of the corrosion features between the specimens with and without the SPT are not obvious under salt spray exposure for 144 hours. The prior corrosion location is the thermal-mechanical affecting zone (TMAZ), which locate between base metal and welded seam. The corrosion types are mainly composed of pitting, intergranular and exfoliation corrosion with increasing the corrosion time. The SPT does decrease the corrosion rate but not change the nature of the corrosion.