Effect of Different Filler Wires on Mechanical Property and Conductivity of Aluminum-Copper Joints

The 1060 aluminum and T2 copper were joined by the pulsed double electrode gas metal arc welding (DE-GMAW) brazing method by using four types of filler wires, namely pure aluminum (Al) ER1100, aluminum-magnesium (Al-Mg) ER5356, aluminum-silicon (Al-Si) ER4043, and Al-Si ER4047, respectively. The effects of different types of filler wires on intermetallic compounds, microhardness tensile strength, and conductivity of joints were investigated. The results showed that a lot of brittle intermetallic compounds laying in the copper side brazing interface zone were generated using pure Al, Al-Mg, and Al-Si filler wires, which caused the change of microhardness, tensile strength, and the conductivity of joints. Meanwhile, with the increase in Si elements contents for Al-Sifiller wires, the thickness of the intermetallic compound layers decreased obviously, which was only up to 3 µm and the conductivity of the joints decreased. In addition, the microhardness, tensile strength, and the conductivity of the joints, when using Al-Sifiller wires, was higher than that using pure Al and Al-Mg filler wires. Hence, in comparison to the pure filler wires and Al-Mg filler wires, the Al-Si filler wires were more suitable for Al-Cu joints by DE-GMAW as Si element content was lower.