LAUSR

Abstract Open-cell copper (Cu) foam has comprehensive application prospects in the thin-film electrode production of high-capacity batteries. However, the lack of high-quality welding techniques for open-cell Cu foam has thus far limited its further application. High porosity open-cell Cu foam and 1A99 aluminum (Al) sheet have been reliably joined utilizing ultrasonic spot welding under very low welding-energy conditions. The real-time temperature, three-dimensional surface morphology, tensile strength, weld interface morphology and composition, fracture morphology, and electrochemical performance of the joints were systematically evaluated. The structure and properties of the foam copper were preserved to the greatest extent, and the optimum joint tensile strength was about 89% of the Cu foam base metal. All the joints presented good toughness characteristics and favorable corrosion-resistance quality, fractures occurred at the edge of the weld spot on the Cu foam side. The peak temperature of the welding interface was much lower than the Al-Cu solid-solution temperature. No intermetallic compounds were found at the weld interface. The open-cell Cu foam and solid Al sheet were joined through atomic diffusion and mechanical locking. USW have been demonstrated to be a feasible method for reliably joining open-cell Cu foam and Al sheet.