Magnetic pulse-assisted semi-solid brazing of Cu/Al tube joints and oxide film removal mechanism

Abstract. In this paper, the advantages of magnetic pulse welding, brazing and semi-solid forming are combined to propose magnetic pulse-assisted semi-solid brazing (MPASSB) to join copper and aluminum tubes. Based on 3D electromagnetic-structural-fluid finite element simulations, the high-speed impact of the aluminum tube on the filler metal will drive the high-speed shear rheology of the semi-solid filler metal. Based on 2D FEM-SPH finite element analysis, the aluminum tube will have a strong interaction with the filler metal during the high-speed impact on the filler metal, which is conducive to the removal of the oxide film on the surface of the copper-aluminum tube and the promotion of element diffusion. Microscopic characterization of the joints revealed that the interfacial oxide film had been completely removed, achieving interfacial metallurgical bonding, and no brittle copper-aluminum intermetallic compounds were found at the interface, with a shear strength of 40 MPa.