Ultrasonic-Assisted Semi-Solid Forming Method and Microstructure Evolution of Aluminum/Copper Brazed Joints

Abstract

Aluminum/Copper dissimilar metal connection devices have been widely used in equipment manufacturing. Ultrasonic vibration assisted semi-solid brazing technology is beneficial to improve brazing quality by using the good flow ability and strong deformation resistance of brazing alloy when it is in a semi-solid state. In this study, a new ultrasound-assisted high-frequency induction brazing method was used to braze aluminum and copper dissimilar metals under non-vacuum conditions with non-prefabrication of brazing filler metal. In a short time, uniform semi-solid brazed joint was obtained. Detailed investigations on the effects of aluminum-substrate side (Abbreviated as Al side) heat dissipation rate and ultrasonic vibration duration on the microstructure evolution and mechanical properties of semisolid weld were conducted. The results show that the welding seam obtained by the modification method increases the microstructure uniformity of brazing joint.

Influence of Filler Alloy on Microstructure and Properties of Induction Brazed Al/Cu Joints

“…A thin interfacial layer is found in all induction brazed joints. There is no eutectic phase in the joints which is different from the braze joint made by Zn-Al filler metals [21][22][23][24][25][26][27] . The thickness of the interfacial layer is about 2~3μm for all joints, which is far less than the thickness of the filler foil with 60~80μm.…”

“…For Zn-22Al-(0.5~2)Si filler material, Si can prevent the diffusion of atoms and change the growth rate and morphology of CuAl 2 , which improve the corrosion resistance of the joint 24 . Moreover, Al x Cu y Zn z was formed in the interface layer when Zn-22Al-1.5Si filler material was used to ultrasonic assisted braze Al to Cu 25 . For Zn-22Al-xTi filler material, the doping of Ti in Zn-22Al filler material can limit the formation of IMCs and change the morphology of Cu 9 Al 4 26 .…”