Mechanism of simultaneous improvement of mechanical performance and conductivity of TiC/Cu composites prepared by laser powder bed fusion

It is difficult to fabricate dense and high-performance pure copper with most commercial medium-power fiber laser additive manufacturing machines due to its high laser reflection and thermal conductivity. The modification of the copper surface with high laser absorptance particles is an economical and effective way. However, the additions of high laser absorptance particles improve mechanical performance but worsen the conductivity of copper, and the mechanism is unclear. In this work, a comprehensive investigation of the effect of TiC nanoparticles and different copper powder sizes on the densification behavior, microstructures, mechanical properties, and electrical conductivity of LPBF-processed copper was completed. The results showed that the coarse copper powder (CCP) with TiC nanoparticles had a better adaption to processing parameters. Under the same process condition, a relative density of 98.8 ± 0.3%, ultimate tensile strength of 213 ± 1 MPa, elongation of 30.9 ± 2.9%, and electrical conductivity of 67.9 ± 0.2% IACS were achieved in CCP composite which was all superior to the fine one. The paper provides a new strategy to fabricate balanced-performance copper by common commercial LPBF devices. © 2024 Published by Elsevier B.V.