Hardness, Microstructure and Corrosion Behaviour of WC-9Co-4Cr+TiC Reinforced Stainless Steel

WC-9Co-4Cr+TiC particles reinforced 304L austenitic stainless steel (ASS) matrix composites (MMCs) were fabricated by laser melt injection (LMI) technique. The morphologies and microstructures of the composite coatings were investigated using optical (OPM) and high resolution scanning electron microscopes (SEM). The consistituent phases and elements were observed using xray diffraction (XRD) and energy dispersive spectrometry (EDS) respectively. The microhardness measurements were carried out using the Vickers tester. Experimental results revealed that the MMCs layers were crack free but with irregular distribution of TiC-aggregates. The top of the alloyed zone comprises of undissolved big and round clusters of WC as well as faceted dendrites. The middle and bottom parts of composite layer exhibit regular microstructure with finely distributed WC dendrites. A significant increase in microhardness of the stainless steel matrix was achieved, from 236 to 1016 H-v0.1. The corrosion properties of the WC-9Co-4Cr+TiC reinforced stainless steel were the most improved compared with other MMCs studied.