Abstract
Three-dimensional (3D) printing of Cu items is a new way to build up the structured Cu materials, but 3D printing of Cu items is usually a challenge because of the high melting point, high thermal conductivity, and high light reflection rate of Cu material. In this study, the composite of Cu microspheres powder and Cu nanoparticles (micro/nano Cu powder) is used to realize the 3D printing of Cu items with the selective laser melting technology. The sintering temperature and the thermal conductivity of micro/nano Cu powder are evidently decreased due to Cu nanoparticles' addition in the micron Cu powder. The results reveal that the 3D printing of 50%/50% micro/nano Cu powder needs laser power range of 100-240 W, which is in contrast to 200-340 W for 3D printing of 100% Cu microspheres powder. Furthermore, the conductivity, mechanical strength, and density of 3D-printed Cu items are improved with the addition of Cu nanoparticles into the micron Cu powder. The increasement of 34% on electrical conductivity and 17% on tensile strength are reached by the addition of 50% Cu nanoparticles with the laser power of 240 W.