Study on the in-situ generation of hard phases and microstructural and mechanical properties in Ni-WC/W2C cladding layers prepared by TIG arc

Abstract

Using the principle of in-situ generation, tungsten carbide particles were generated in-situ on 40Cr surfaces pre-coated with self-made powders by TIG arc with flux-cored wires, and the in-situ generation process of hard phases such as WC/W₂C was systematically investigated. The macroscopic morphology and microstructure of the cladding layers were analyzed using optical microscopy (OM), scanning electron microscopy (SEM), energy spectrometry (EDS), and X-ray diffractometry (XRD), and the hardness and wear resistance of the cladding layer were tested. The results show that the in-situ grown WC exhibits a positive triangular shape in the two-dimensional plane. No defects such as porosity and cracks are seen in the cladding layer, and the hard phase mainly consists of WC/W₂C, as well as carbides with three typical morphologies of dendrites, rods, and ring-block. With the combined effect of residual tungsten carbide particles and in-situ grown hard phase, the optimal hardness and wear volume of the cladding layer were 664.4 HV₁ and 0.33 mm³, respectively, which were increased to about 3 and 45 times that of the substrate.