Mechanical behaviors of lotus-type porous Cu/Cu joint soldered by Sn-3.0Ag-0.5Cu alloy

Lotus-type porous Cu with cylindrical pore aligned in the single direction was joined to Cu substrate using Sn-3.0Ag-0.5Cu solder. The joint microstructure, joining strength, and fracture mechanisms of lotus-type porous Cu/Cu joints were investigated. The molten solder was infiltrated into pores of lotus-type porous Cu during the soldering. A Cu–Sn intermetallic layer at the interface between pore walls and the solder was formed. In the shear test result, the joining strength of lotus-type porous Cu joints was weaker than non-porous Cu joint, whereas the joint ductility was higher. However, both the joint strength and ductility were enhanced in the lotus-type porous Cu joint under the tensile mode. The energy absorption ability of lotus-type porous Cu joints was enhanced compared to that of non-porous Cu joint. The fracture analysis indicated that the pore structure at joint interface delayed the crack propagation of lotus-type porous Cu joints. •Lotus-type porous Cu/Cu joints was fabricated by Sn-3.0Ag-0.5Cu solder with different pore directions.•The molten solder was infiltrated into the cylindrical pores by capillary effect during soldering process.•The joint microstructure was mainly composed of Cu–Sn IMCs and Sn-3.0Ag-0.5Cu solder.•The effect of pore structure on the mechanical behaviors was investigated under both shear and tensile loading.