Mechanical strength enhancement of ultrasonic metal welded Cu/Cu joint by Cu nanoparticles interlayer

A sound ultrasonic metal welded Cu/Cu joint was obtained via the addition of copper nanoparticles (Cu NPs) interlayer. Cu NPs, synthesized through simple routes, had an average diameter of 45 nm. Hard Cu NPs were conductive to enhance the quantity of friction heat production and activate the surface of base metal, leading to the formation of more effective welded areas. The peak T-peel failure load of the Cu/Cu joint with Cu NPs interlayer was 281.4 N, which was 17.9% higher than that (238.6 N) of the Cu/Cu joint without Cu NPs interlayer. Moreover, due to the addition of Cu NPs interlayer between the Cu sheets, scratched regions in the fracture surface disappeared.