Pure copper layer formation on stainless-steel and aluminum substrate with a multibeam laser metal deposition system with blue diode laser

Laser metal deposition (LMD), which is one of the additive manufacturing technologies, is suitable for making 3D objects with complex shapes. In this method, a blue diode laser is used to explore the formation of pure copper parts because of the high light absorption of pure copper in blue light. Inspired by this method, in this study, we developed a high-power blue diode laser with a wavelength of 450 nm. This laser had an output power of 100 W and a fiber core diameter of 100 μm. We also developed a multibeam LMD system with the blue diode laser in which metal powder was supplied perpendicularly to the processing point and multiple lasers were irradiated from the surroundings for additively manufactured pure copper. We investigated the differences in copper layer formation that are dependent on the properties of substrates. Upon using the multibeam LMD system, a pure copper layer formed on pure aluminum and stainless-steel substrates. The interaction of pure copper powder and the substrates was observed using a high-speed video camera. After laser irradiation, copper cladding samples were observed with an optical microscope and scanning electron microscope and energy dispersive x-ray spectroscopy to evaluate the cross-sectional area of the pure copper layer and the dilution zone. As a result, a pure copper layer formed on the aluminum surface under the laser irradiation condition under which the aluminum substrate was not subjected to melting by heating with the blue laser. It was suggested that the pure copper powder heated by the laser melted the aluminum and formed a copper layer on the aluminum substrate.