Fabrication of Pure Copper Rod by Multi-beam Laser Metal Deposition with Blue Diode Lasers

Abstract

A three-dimensional rod of pure copper was fabricated by multi beam type laser metal deposition method with blue diode lasers. In order to clarify the mechanism of the 3D rod formation, the melting and solidification process during a rod formation was captured with a video camera. The pure copper rod with a length of 100 mm was successfully formed in 25 seconds at the power density for blue laser of 1.6×104 W/cm2. In order to evaluate the rod shape, the cross-sectional area was measured. As the results, the long side of the formed pure copper rod was 780 μm and the short side was 600 μm, which was larger than the spot at the focal point. Furthermore, in order to evaluate the mechanical properties, tensile strength and hardness of the rod were measured. The rod had a maximum tensile strength of 229 N/mm2 and an elongation rate of 30%, which was low ductility. The fractured part was analyzed using a scanning electron microscope. As a result, it was found that the fracture surface of the rod was inhomogeneous with scattered holes.