Microstructure, mechanical and corrosion properties of electron-beam-melted and plasma-transferred arc-welded WC_P/NiBSi metal matrix composites

As one of the new additive manufacturing processes, electron beam melting (EBM) has seen its promising potential in the fabrication of metal matrix composites (MMCs) components with complex geometries. In this work, WC_P/NiBSi MMCs were fabricated by EBM and plasma-transferred arc welding (PTAW) for a comparative study. The microstructures of both samples were examined using a scanning electron microscope (SEM) equipped with an electron backscattered diffraction (EBSD) detector. The macrohardness was tested using a Rockwell hardness method (Type C), while the microhardness was measured using different loadings (0.5–1.0 N) based on different phases. The anti-abrasion performance was tested as per the ASTM G105 standard. The corrosion behavior of the MMCs was also assessed by potentiodynamic polarization. The results indicate that the EBM bulk and the PTAW cladding MMCs exhibit different microstructures due to the different local solidification conditions. This is believed to lead to the varied mechanical properties and corrosion resistance of the MMCs, and the possible mechanisms were also discussed.