Microstructure transformation and mechanical properties of Al alloy joints soldered with Ni-Cu foam/Sn-3.0Ag-0.5Cu (SAC305) composite solder

In this study, Ni-Cu/SAC composite solders with different Cu contents were used as an interlayer to solder Al alloy joints at 250 ℃ for time. The results showed that the formation and evolution of microstructure affected by contents. Ni18Cu/SAC joint, Sn was completely consumed form a solid-phase joint in 5 min. And (Cu,Ni)6Sn5 initial phase formed from reaction between Ni18Cu skeleton. Due higher Ni concentration than skeleton, atoms diffused skeleton replaced it. As result, content increased continuously, transformed into (Ni,Cu)3Sn4 10 Phase transition also occurred Ni38Cu/SAC joints. However, Ni38Cu (Ni,Cu)3Sn4. Therefore, min because On increasing soldering time, shear strength first then decreased, soldered exhibited highest 58.3 MPa, shearing failure mainly happened layers.