Modification of Electrical and Mechanical Properties of Selective Laser‐Melted CuCr0.3 Alloy Using Carbon Nanoparticles

Abstract

Herein, the influence of carbon nanoparticle addition on the selective laser melting (SLM) behavior and the resultant properties of gas‐atomized CuCr0.3 powder are investigated. The carbon addition neither affects the powder flowability, nor its packing density, but it significantly enhances the optical absorption for infrared radiation. Despite the improved optical absorption of the powder bed after carbon addition, a comparable SLM behavior is observed for both virgin and carbon‐mixed CuCr0.3 powders. Furthermore, the addition of carbon nanoparticles facilitates in situ deoxidation of copper and chromium oxides present in the CuCr0.3 powder. Accordingly, a larger fraction of chromium is obtained in its metallic form in the as‐built carbon‐mixed CuCr0.3 part. The presence of metallic chromium allows tailoring of the mechanical and electrical properties by postheat treatments (HTs). The best combination of mechanical (tensile strength of 298 ± 19 MPa, yield strength of 208 ± 18 MPa, ductility of 21 ± 4%) and electrical (87 ± 1% international annealed copper standards [% IACS]) properties is realized for the carbon‐mixed CuCr0.3 alloy after a direct age hardening HT. The improvement in mechanical properties is attributed to the precipitation of nanometer‐sized, coherent, and metallic chromium precipitates in the copper matrix.