Microstructure and Mechanical Properties of Al-Cu Joints by Cold Spray Bonding

The cold spray bonding method had been applied to connect the pure aluminum and copper in ambient environment under nitrogen gas at 2.4 MPa and 270 ℃, which can eliminate the brittle intermetallic compounds of welded joints under fusion welding process due to the physical mismatches in densities, melting points and elasticity modules. In this method, solid-state pure aluminum particles with high-speed impacted on the substrate. The stainless steel particles is added in the feedstocks that assisted to improve the mechanical properties of joints. The results of mechanical properties at the bonding joints show that the average tensile strength of bonded joints is about 63 MPa; the average shear strength of Cu-Al and Al-Al bonding interface is 38 MPa and 42 MPa, respectively. The joint is mainly connected to the base metals by mechanical interlocking; the plastic deformation of pure aluminum particles, the strength and density of bonded joints are significantly enhanced with the in-situ tamping effect from the stainless steel particles. The interlocking effect from the stainless steel particles embedded in the base materials can effectively improve the shear strength of the bonding joints.