Microstructure and mechanical properties enhancement of WC-10Co cemented carbide with Y2O3 and VC composite additives

Abstract

By employing a liquid-liquid doping method to introduce Y₂O₃ and VC into WC-Co composite powders, WC-10Co cemented carbide with uniform microstructure and excellent performance was successfully prepared through low-pressure sintering. The effects of Y₂O₃, VC, and their composite addition on the microstructure and mechanical properties of WC-10Co cemented carbide were investigated. The results indicate that as the content of Y₂O₃ and VC increases, the WC grain size in WC-10Co cemented carbide reduces significantly. Compared to Y₂O₃, the addition of VC has a more pronounced effect in inhibiting grain growth. A suitable amount of VC has a stronger effect on improving the hardness and transverse rupture strength of WC-10Co cemented carbide, while an appropriate amount of Y₂O₃ is more effective in enhancing its fracture toughness. When Y₂O₃ and VC are co-doped, not only is WC grain refinement achieved, but the overall uniformity of WC-10Co carbide grains is also improved, thereby enhancing the mechanical properties of WC-10Co cemented carbide. In particular, when a combined additive of 0.25 wt% Y₂O₃ and 0.25 wt% VC is added, the WC-10Co cemented carbide exhibits the most uniform microstructure and optimal comprehensive mechanical properties. The alloy exhibits an average WC grain size of 0.64 μm, a relative density of 99.96 %, a Vickers hardness of 1783 HV₃₀, a fracture toughness of 12.55 MPa·m^1/2, and a transverse rupture strength of 3600 MPa.