Microstructure and Mechanical Properties of Resistance Heat-Assisted High-Power Ultrasonic Dissimilar Welded Cu/Al Joint

Abstract

The Cu/Al dissimilar joint, welded by high-power ultrasonic welding technology, is still facing challenges despite the significant research attention it has attracted. In this work, the microstructure and mechanical properties of resistance heat-assisted high-power ultrasonic welding of Cu/Al are investigated, in order to obtain high-quality joints. The intermetallic compound (IMC) at the interface of hybrid welding is primarily composed of Al2Cu, and the additional resistance of heat reduces the thickness of this brittle IMC layer. The average shear stress for the joint prepared by hybrid welding is~97 MPa, which is higher compared to the joint strength without resistance heat (90 MPa). Moreover, the duration of the hybrid welding process is shorter. Finally, the fracture of the hybrid weld is found to be a brittle-ductile hybrid mode.

Friction Stir Spot Welding of Aluminum and Copper: A Review

“…Solid-state welding processes (FSW, FSSW, USW, EMPW, etc.) have been widely applied to retard the growth of brittle IMCs on the interfaces of dissimilar metals [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. As a solid-state welding process, friction stir welding (FSW, invented by TWI, 1991 [13][14][15][16]) can avoid the aforementioned problems in Al-Cu fusion welding joints to a considerable degree due to its low welding temperature and the fierce stirring effect during dynamic welding process.…”