Comparative study of WC-Co-VC-Cr3C2 cemented carbide by spark plasma sintering: densification, microstructure, and mechanical properties

Ultrafine-grained WC-Co-VC-Cr3C2 cemented carbide was consolidated from homogeneously synthesized powder using spark plasma sintering at 1300 degrees C under 60 MPa. The densification behavior of WC-Co-VC-Cr3C2 was determined based on the shrinkage strain with sintering kinetics. As the Cr3C2 addition increased, the secondary (Cr, W)Cx phase was attributed to abnormal grain growth in the basal facet of WC, whereas grain boundary strengthening was induced by the separation of the WC/Co interface with the addition of VC. The mechanical properties of WC-Co-VC-Cr3C2 cemented carbide depend on the grain size and lattice strain of the hard phase, in contrast to the toughening mechanism, and were correlated with the crack propagation and fracture resistance. The WC-Co-Cr3C2 cemented carbide with the best combination of mechanical properties was found, including a hardness of 1958.9 kg/mm(2) and fracture toughness of 7.3 MPa.m(1/2).