Microstructural Characteristics of WC‐Cu Cladding on Mild Steel Substrate Prepared Through Plasma Transferred Arc Welding

In this study, a WC-Cu composite coating was successfully fabricated on a mild steel substrate using the novel Plasma Transferred Arc (PTA) welding technique. Phase identification was carried out using X-ray diffraction (XRD), while microstructural evolution was analysed through scanning electron microscopy (SEM). The results indicate that WC particles predominantly interacted with Fe from the substrate, leading to the formation of complex carbides, primarily of the M₁₂C type, within the solution matrix. In contrast, Cu was observed to segregate and remain in discrete regions near the top surface of the coating. The M₁₂C carbides precipitated in two distinct morphologies: coarse, faceted dendritic structures forming equiaxed branches, and herringbone-shaped eutectic structures distributed along the α-Fe grain boundaries. The formation and growth of the eutectic M₁₂C phase was strongly influenced by the thermal gradients and solidification dynamics associated with the PTA welding process. This study highlights the potential of PTA welding for producing wear-resistant composite coatings with tailored microstructures through controlled solidification behaviour.