Induction diffusion brazing of copper to aluminium

Abstract

The aim of this research was to develop an induction diffusion brazing to obtain a sound joint between copper and aluminium. A foil interlayer was used to bond copper to aluminium at 600°C for 2 s under a bonding pressure of 9 MPa. The failure of tensile test is in the aluminium side and no failure occurs when the joint is bent to 180°. The electrical resistivity of joint is lower than that of aluminium. The interfacial intermetallic compounds layers are Cu 9 Al 4 and CuAl 2 with the total thickness of 2 μm. No voids and oxide scale are found in the joint. Heat treatment shows that induction diffusion brazing is superior to conventional flash welding to maintain electrical stability and mechanical integrity of copper to aluminium joint.

Metallurgical joining of aluminium and copper using resistance spot welding: microstructure and mechanical properties

“…diffusion bonding [5], magnetic pulse welding [6], ultrasonic welding [7], friction stir welding [1, 4, 8]) where welding peak temperature is below the melting temperature of Al, solid/liquid interface (e.g. laser brazing [9], resistance spot welding (RSW) [10, 11], diffusion brazing [12]) where Al alloy or interlayer experiences melting and wets the solid Cu and liquid/liquid interface (where the heat input is so high enabling melting of both Al and Cu side). The formation of a thin and continuous IMC layer is essential for producing a strong metallurgical bond between very dissimilar metals such as Al and Cu [13].…”

Influence of Interfacial Inter-metallic Compounds on the Electrical Characterization of Cu/Al Joints Produced by Flash Welding and Diffusion Brazing

“…The high speed upset expelled remaining molten metal and then forged copper and aluminum together as shown in Figure 1a. The diffusion brazed Cu/Al joint was prepared according to the method described in our previous works 10,21,22 . .…”

“…Further research shows that the electrical resistance of the Cu/Al joint is not affected significantly by the thickness of the IMCs if its thickness is lower than the critical thickness. The critical thickness of the IMCs depends on the welding method, such as 2μm for friction welding [5][6][7] , ultrasonic welding 9 and diffusion bonding 10 , 5μm for explosive welding 11 . That is to say, the thin IMCs cannot increase the resistance of Cu/Al joint.…”

Effect of Al Content on the Microstructure and Properties of Zn-Al Solder Alloys

“…However, these techniques are complicated and difficult to apply quickly. Brazing has become a popular process for creating Cu/Al hybrid structures due to its little influence on the base material, its smooth and flat connections, and its ease of automation in product manufacturing [4,12,13].…”