Microstructure and texture evolution of aluminum and titanium ultrasonic welded joints

Aluminum and titanium alloy joints were fabricated by ultrasonic welding (USW). The interface microstructure and mechanical properties of the Al/Ti joint were investigated. A relatively sufficient metallurgical bonding was achieved at the welding time of 0.3 s, after which the fracture pattern of the joint transformed from interfacial failure to nugget pull-out failure, and the shear load reached a stable level, with a maximum lap shear load of 3650 N. Electron backscatter diffraction (EBSD) was performed to analyze crystallographic characteristics in the faying interface. It revealed that dynamic recrystallization (DRX) mainly occurred at the interface of the Al side owing to severe plastic deformation and heat generation.