VC, Cr3C2 doped ultrafine WC–Co cemented carbides prepared by spark plasma sintering

Abstract The influence of the addition of 0.3, 0.5 and 0.7 wt.% VC on the density, microstructure and mechanical properties of WC–Cr3C2–11 wt.% Co with 0, 0.2, 0.4 and 0.6 wt.% Cr3C2 hard metals prepared by spark plasma sintering (SPS) at a temperature of 1200 °C (5 min, 40 MPa) was investigated. Microstructure analysis revealed that the WC grain size in the sintered hard metals was strongly influenced by the VC and Cr3C2 content. With the addition of inhibitors and the increased amount of Cr3C2, the density is reduced, and on the contrary, the addition of VC as an inhibitor contributes to promoting the densification. The combined addition of Cr3C2 and VC could strongly reduce the WC grain growth to about 350 nm. Observation suggests that the fracture of WC–Co cemented carbide is brittle and intergranular. The amount of added VC/Cr3C2 should be controlled in a certain range. Samples with an appropriate proportion of VC/Cr3C2 added exhibit higher hardness which can be up to 1938 HV30. Toughness, too, can reach 16.34 MPa m1/2.