Copper alloys for additive manufacturing: Laser powder bed fusion of CuCr1Zr by using a green qcw-laser

Abstract

Due to the high electrical conductivity in combination with high strength, the copper alloy CuCr1Zr plays an important role for industrial applications. Here, additive manufacturing of CuCr1Zr enables new fields of application due to a higher degree of freedom, as well as the materials design flexibility. However, the high thermal conductivity and the low absorptivity of the laser radiation of copper reduce the efficiency of the additive manufacturing process significantly. An improvement of the manufacturing process can be achieved by using a green laser source with a wavelength of 532 nm. The first parameter study via a design of experiments approach for the laser power bed fusion process of CuCr1Zr by using a green quasi continuous-wave laser is presented in this work. A maximal relative density of 99.6% was obtained for a laser power of 125 W, a scanning speed of 400 mm/s, and a hatching distance of 100 µm. A strong dependency of the relative density on the laser power and the hatching distance was observed. Moreover, the microstructure evolution comes along with the occurrence of zirconium oxides within the powder as well as within the additively manufactured samples.