On processing of Ni-WC based functionally graded composite clads through microwave heating

Present study focuses on the development of four layered functionally graded clads (FGC) of Ni-WC based composite material on AISI 304 substrate through microwave heating route. Experimental trials were conducted inside a microwave applicator of domestic type at frequency range of 2.45 GHz. The optimal exposure time of 900 W microwave power was varied with compositional gradient and it was from 300 to 360 s. The mechanism of FGC formation through microwave heating was explained and developed FGC was subjected to mechanical and microstructure characterizations. The results of micro-structural analysis revealed that the FGC of ∼1.8 mm thickness was produced and was free from any type of interfacial cracks and visible porosity. It was observed that WC particles were randomly dispersed in the nickel matrix. XRD study revealed the formation of inter-metallics, such as NiW4, NiSi, and Cr23C6. Maximum value of microhardness was observed in the top FGC layer and was 880 ± 30 HV.