Impact of electromagnetic stirring upon weld quality of Al/Ti dissimilar materials resistance spot welding

The impact of electromagnetic stirring (EMS) upon the microstructure and mechanical properties of the Al/Ti resistance spot weld was investigated. The microstructures in the Al/Ti resistance spot weld joint were characterized by comparing them to those in an Al/AI resistance spot weld joint, and the effects of the welding current, welding time, and electrode force upon the tensile shear properties were also studied. The microstructure in the traditional Al/Ti joint consisted of a partially melted zone, a columnar grain zone, and a transition structure. Under the action of EMS, a fine spheroidal grain structure formed in the Al/Ti joint and, compared with the traditional Al/Ti resistance spot weld, the weld created under the EMS effect exhibited a larger bonding diameter, and higher tensile shear force and energy absorption. The large bonding diameter and fine spheroidal grain structure should account for the superior mechanical performance of the Al/Ti EMS joint. (C) 2015 Elsevier Ltd. All rights reserved.