Influence of ultrasonic impact treatment on corrosion resistance of 7075 aluminum alloy welded joint

Abstract To enhance the resist corrosion and service safety of 7075 aluminum alloy FSWed joints, an ultrasonic impact treatment was applied, and its effects on the surface morphology, microhardness, residual stress, and corrosion performance of the welded joint were investigated. The experimental results showed that after impact, the surface of the welded joint exhibited larger undulations. The distribution trend of micro-hardness changed from a “W” distribution to a uniform distribution, and the tensile residual stress (TRS) on the surface of the welded joint transformed into compressive residual stress (CRS). After the ultrasonic impact treatment, only minimal pitting corrosion occurred on the welded joint, and the corrosion current density decreased, while the capacitance arc radius increased. The resist corrosion of the welded joints was ameliorated.