Interfacial reaction behavior and mechanical properties of 5A06 Al alloy soldered with Sn-1Ti-xGa solders at a low temperature

Active soldering of 5A06 Al alloy was performed at 300 °C by using Sn-1Ti and Sn-1Ti-0.3Ga active solders, respectively. The effects of soldering time on the microstructure and mechanical properties of the joints were investigated. The results showed that the Sn-1Ti solder broke the oxide film on the surface of the Al substrate and induced intergranular diffusion in the Al substrate. When Ga was added to the solder, severe dissolution pits appeared in the Al substrate due to the action of Sn-1Ti-0.3Ga solder, and many Al particles were flaked from the matrix into the solder seam. Under thermal stress and the Ti adsorption effect, the oxide film cracked. With increasing soldering time, the shear strength of 5A06 Al alloy joints soldered with Sn-1Ti and Sn-1Ti-0.3Ga active solders increased. When soldered for 90 min, the joint soldered with Sn-1Ti-0.3Ga solder had a higher shear strength of 22.12 MPa when compared to Sn-1Ti solder.