Achieving ultra-high efficiency in directed energy deposition of pure copper on Inconel 718 substrate with a 3500 W blue laser

High efficiency deposition of highly reflective copper on a nickel-based superalloy substrate presents a significant challenge. This study first used a 3500 W high-power and 7.5 mm2 large-spot blue laser in Directed Energy Deposition, and successfully deposited copper on an Inconel 718 substrate. The process exhibited stability, with no significant cracks or pores observed. To the best of our knowledge, we have achieved the highest cladding efficiency of 62.84 mm2/s in the current cladding of copper. The interface between copper and Inconel 718 displayed a smooth composition transition at 3500 W, and the width reached 418 μm. The cladding layer displayed a columnar dendritic morphology at the bottom, gradually transitioning to equiaxed dendrites at the top. Dendrites enriched in elements found in Inconel 718 solidified, while Cu from the powder mainly solidified in the interdendritic region. The utilization of a high-power, large-spot blue laser offers a promising process for the efficient fabrication of large Cu/Ni dissimilar structural components.