Microstructure and mechanical properties of ultrasonic spot welding TiNi/Ti6Al4V dissimilar materials using pure Al coating

Abstract

Abstract Ultrasonic spot welding of Ti6Al4V and TiNi shape memory alloy (SMA) dissimilar joints with an Al coating interlayer were investigated. The influence of welding pressures on the macro/microstructures and tensile shear properties were evaluated. The results show that successful joining of Ti6Al4V and TiNi SMA dissimilar materials can be achieved by selecting proper welding pressure. Intermetallic compounds such as Al3Ti were formed in the dissimilar material joints. The tensile shear loads of the joints were increased first then decreased as the welding pressure continually increasing. When the welding pressure and welding time is 0.52 MPa and 0.5 s respectively, the tensile shear load was 931 N. The dissimilar alloy joints failure at the interface of Al coating and TiNi SMA with a brittle fracture mode.