Fundamental investigation on the impact of Cu powder oxidation states on processability by powder bed Fusion-Laser Beam/Metal (PBF-LB/M)

• Targeted oxidation of Cu powders at 200 °C and 300 °C forms controlled oxide layers (350–2000 nm) and modifies surface chemistry, improving processability in PBF-LB/M. • Reflectivity at 1070 nm decreases to ∼ 55.7 % for 300 °C-oxidized powders, enabling dense Cu microstructures (99.5 % relative density) without preheating or high laser power. • Samples from 300 °C-oxidized powders achieve significantly higher hardness (∼164 HV0.1) and moderate conductivity (∼60 % IACS), comparable to CuCrZr alloys. • Controlled oxidation stabilizes powder behavior, enhances energy coupling, and may improve reusability compared to virgin Cu powders. • Findings demonstrate that dense Cu structures can be produced on widely available infrared-laser PBF-LB/M systems, overcoming power limitations. This study introduces targeted oxidation of Cu powders as a strategy to improve both laser power coupling and powder reusability for the PBF-LB/M process. Controlled surface oxidation at 200 °C and 300 °C reduces reactivity toward residual oxygen in the process atmosphere, stabilizes absorption, and eliminates the need for high baseplate preheating or increased laser power. Therefore, powder properties, oxide formation, and PBF-LB/M−produced samples were systematically characterized. X-ray photoelectron spectroscopy (XPS) and synchrotron X-ray diffraction (XRD) were employed to identify the surface phases. The fabricated samples were then analyzed with respect to their microstructure, hardness, and electrical conductivity. Results demonstrate that oxidation at 300 °C enhances energy absorption without significantly compromising powder flowability, thereby enabling the production of dense microstructures. Oxidation at 300 °C yielded a Cu matrix with ∼ 17 vol% Cu 2 O, resulting in ∼ 60 % IACS electrical conductivity but increased hardness (∼160 HV0.1). The findings demonstrate that through targeted oxidation, dense copper structures can be manufactured even with the most widely used PBF-LB/M systems, which typically operate with infrared-emitting lasers that are often limited in terms of laser energy.