High-Power Laser Powder Bed Fusion of Pure Copper for Simultaneous Achievement of High Density and Electrical Conductivity

Pure copper is in high demand for energy and electronic applications due to its superior electrical and thermal conductivities. However, producing dense metals such as copper by laser powder bed fusion (L-PBF) has long been challenging due to their high infrared reflectivity and thermal conductivity, which can destabilize melting and process stability. In this study, a high-power infrared fiber laser system was employed to characterize the processing parameters, enabling high density and electrical conductivity without post-heat treatment or observable optical degradation during processing. A critical volumetric energy density (VED) of approximately 228.76 J·mm⁻³ was identified as the threshold for stable melting, achieved at laser powers ≥ 700 W and scanning speeds ≤ 650 mm·s⁻¹. In addition, a linear energy density (LED) ≥ 1.0 J·mm⁻¹ was required to maintain consistent densification behavior. Under these optimal conditions, the fabricated parts achieved a maximum relative density of 98.9% and an electrical conductivity of up to 100.0% IACS, demonstrating performance comparable to that of wrought copper. Electron backscatter diffraction (EBSD) analysis revealed that electrical conductivity was influenced by both porosity and crystallographic orientation. Specifically, a higher ⟨101⟩ texture fraction and a lower grain-boundary density resulted in reduced electron scattering. These results demonstrate that high-power infrared L-PBF can reliably fabricate pure copper with industrial-level stability in terms of bulk density and conductivity, providing guidelines for the large-scale manufacturing of future electrical and thermal components.