Laser Cladding on Copper with Composite Powder C-Al₂O₃-Cu

Copper and copper alloys own high thermal conductivity, electrical conductivity, good plasticity, and corrosion resistance, which are widely used in electric power, aerospace, and marine engineering. Due to low absorption rate of infrared and near infrared light, high thermal conductivity and high activity with oxygen, laser cladding of copper, and copper alloys are difficult to be conducted in air since the problems associated to cracks and voids are always hardly to be eliminated. In this paper, C-Al₂O₃-Cu composite powder mixed with Ni and Fe was developed to solve these problems. Use of carbon was to depress the oxidation and improve the laser absorption, while alumina was used to improve the laser absorption and mechanical strength. To improve the bonding strength between cladding layer and substrate, Ni and Fe were used. Experimental results showed that no obvious aggregation was observed and the powder showed good fluidity. The tensile strength of the cladding layer is 406.7 ± 0.1MPa which is about 1.7 times higher than that of pure copper substrate, and the tensile fracture of the cladding layer revealed microporous aggregation fracture due to the existence of Al₂O₃ in the cladding layer.