Ultrasound-assisted brazing of Cu/Al dissimilar metals was performed using a Zn-3Al filler metal. The effects of brazing temperature on the microstructure and mechanical properties of Cu/Al joints were investigated. Results showed that excellent metal...
Ultrasound-assisted brazing of Cu/Al dissimilar metals was performed using a Zn-3Al filler metal. The effects of brazing temperature on the microstructure and mechanical properties of Cu/Al joints were investigated. Results showed that excellent metallurgic bonding could be obtained in the fluxless brazed Cu/Al joints with the assistance of ultrasonic vibration. In the joint brazed at 400<SUP>o</SUP>C, the filler metal layer showed a non-uniform microstructure and a thick CuZn<SUB>5</SUB> IMC layer was found on the Cu interface. Increasing the brazing temperature to 440<SUP>o</SUP>C, however, leaded to a refined and dispersed microstructure of the filler metal layer and to a thin Al<SUB>4.2</SUB>Cu<SUB>3.2</SUB>Zn<SUB>0.7</SUB> serrate structure in the Cu interfacial IMC layer. Further increasing the brazing temperature to 480<SUP>o</SUP>C resulted in the coarsening of the filler metal and the significantly growth of the Al<SUB>4.2</SUB>Cu<SUB>3.2</SUB>Zn<SUB>0.7</SUB> IMC layer into a dendrite structure. Nanoindentation tests showed that the hardness of the Al<SUB>4.2</SUB>Cu<SUB>3.2</SUB>Zn<SUB>0.7</SUB> and CuZn<SUB>5</SUB> phase was 11.4 and 4.65GPa, respectively. Tensile strength tests showed that all the Cu/Al joints were failed in the Cu interfacial regions. The joint brazed at 440<SUP>o</SUP>C exhibited the highest tensile strength of 78.93MPa.