Powder bed fusion of pure copper using an electron beam: a comparative study on the material properties obtained using vector- and spot-based exposure

Abstract Additive manufacturing of pure copper is of interest due to the materials thermal and electrical conductivity, corrosion resistance and ductility, as well as the possibility of creating value through the production of complex structures. Powder bed fusion of copper using an electron beam (PBF-EB) is considered promising due to the vacuum atmosphere, the scalable beam power, and the high reflectivity of copper for IR radiation used in state-of-the-art powder bed fusion of metals using a laser beam (PBF-LB/M) machines. In PBF-EB, spot-based exposure strategies are considered a promising approach to overcome issues resulting from vector-based processing with variable vector length such as lack of fusion, local temperature accumulation, and surface swelling. However, the processing of pure copper using spot-based exposure strategies is widely uncovered. This study investigates the transfer of exposure parameters from vector- to spot-based processing of pure copper and compares the relative density, microstructure and physical properties. Both applied exposure strategies yielded relative densities exceeding 99.5%, electrical conductivities exceeding 100% IACS, and thermal diffusivities above 1.17 cm 2 s −1 . Variations in microstructure and mechanical properties are analyzed using electron backscatter diffraction method and attributed to differences in local thermal gradients and solidification speed. The results indicate that, in addition to conventional vector-based exposure strategies, spot-based exposure approaches are also applicable for the fabrication of complex components.