Understanding microstructure and properties evolution in additively manufactured CuCrZr alloy to obtain a high-performance material

CuCrZr is one of the most interesting copper-based alloys due to the combination of high conductivity and mechanical properties. In this work, the material was additively manufactured through Laser Powder Bed Fusion (LPBF) technology. Two machines were used to investigate the influence of the building process on the final properties, an EOSint M280 and AMCM M290-1 kW. Several heat treatments were carried out to evaluate their impact on the mechanical properties and the thermal conductivity: solution annealing + aging, direct age hardening, and an innovative low-temperature annealing, as a stand-alone treatment or followed by an aging treatment. A maximum thermal conductivity of 340 W/mK and an electrical conductivity above 93 %IACS were measured on the samples treated with the low-temperature annealing treatment followed by aging at 550 °C for 3 h. An ultimate tensile strength (UTS) of almost 600 MPa was achieved by treating the material with a direct age hardening treatment at 500 °C for 3 h. In this study, we demonstrate that, for the same powder, different building processes did not affect the material performance. At the same time, heat treatments play a major role in determining the properties. TEM analyses were also carried out on the as-manufactured, solution annealed, and directly aged material, to investigate the precipitation of Cr- and Zr-rich particles and correlate the microstructure and the final properties. • Additively manufactured CuCrZr alloy can reach a thermal conductivity of 340 W/mK. • Porosity plays a minor role in determining the material performance. • Cr is responsible for the performance evolution after heat treatments.