Effect of Y2O3 on microstructure and mechanical properties of WC-Co-cemented carbides prepared via solid-liquid doping method and spark plasma sintering

Abstract

The effect of Y2O3 on the microstructure and mechanical properties of tungsten carbide with 12 wt.% cobalt prepared using a solid-liquid doping method and spark plasma sintering (SPS) was investigated. The novelty of this study is the use of solid-liquid method for addition of Y2O3 into WC-Co material. Composition, microstructures, densities, hardness, and fracture toughness of WC-Co-Y2O3-cemented carbides were analyzed using XRD, SEM, TEM and measuring equipment. Results show that, the existence of Y2O3 hindered the growth of WC grains, and the WC grain size decreased to 0.98 μm. The coherent relationship between Y2O3 phase and WC phase is considered as semi-coherent. Furthermore, Y2O3 did not increase the porosity of WC-based sample, and the sample with Y2O3 added possessed almost full relative density. And the sample with 1.3 wt.% Y2O3 possessed maximum hardness and fracture toughness measured at 1446.9 HV and 11.9 MPa·m1/2, respectively. Therefore, we improved the mechanical properties of WC-Co-cemented carbides with 1.3 wt.% Y2O3 doped via solid-liquid doping method and compared with the Y2O3-undoped WC-Co alloy.