Effect of spark plasma sintering pressure on mechanical properties of WC–7.5 wt% Nano Co

•Effect of sintering pressure on mechanical properties was studied.•Crack initiation, propagation and grain size were analyzed to discuss mechanical properties.•Quantitative measurement of porosity was carried out in reconfirming hardness behavior.•Overall, microstructural characteristics were analyzed to explain hardness and fracture toughness.

In this study, Spark Plasma Sintering (SPS), a relatively fast consolidation method assisted with simultaneous application of heat and pressure, was used to produce bulk carbides from mixed WC–7.5 wt% Nano Co powders. Different pressures ranging from 30 to 80 MPa were applied during sintering to explore its effect on the mechanical properties of resulting carbides. The maximum hardness was found for the samples pressed at 80 MPa, which is ∼1925 HV (18.88 GPa), higher than that of the commercially available cemented carbide tools. The marked changes in porosity, hardness, and crack propagation observed in the samples show that the sintering pressure have considerable impact on the mechanical properties of cemented carbides. In particular, the nature of crack initiation and propagation, which is indicative of the fracture toughness of materials, was studied and clarified.