Novel Method of Aluminum to Copper Bonding by Cold Spray

Cold spray bonding (CSB) has been proposed as a new method for joining aluminum and copper. At high speeds, solid Al particles impacted the groove between the two substrates to form a bond between Al and Cu. Compared to traditional welding technologies, CSB does not form distinct intermetallic compounds. Large stainless steel particles were introduced into the spray powders as in situ shot peen particles to create a dense Al deposit and to improve the bond strength of joints. It was discovered that introducing shot peen particles significantly improved the flattening ratio of the deposited Al particles. Increasing the proportion of shot peen particles from 0 to 70 vol.% decreased the porosity of the deposits from 12.4 to 0.2%, while the shear strength of joints significantly increased. The tensile test results of the Al-Cu joints demonstrated that cracks were initiated at the interface between the Al and the deposit. The average tensile strength was 71.4 MPa and could reach 81% of the tensile strength of pure Al.