Effect of Co content on microstructure and mechanical properties of ultrafine grained WC-Co cemented carbide sintered by spark plasma sintering

The WC-Co cemented carbides with 4 wt%similar to 14 wt% Co content were fabricated by spark plasma sintering. The effect of Co content on microstructure and mechanical properties of WC-Co cemented carbide were analyzed. The results showed that the grain size of cemented carbide with different Co content was in 220-380 nm. As the Co content increased, the density, fracture toughness and flexural strength of cemented carbide increased, but the hardness gradually decreased. The hardness decreased by approximately 1.6 GPa with per 2 wt% increase of the Co content when the Co content was below 10 wt%. The optimal comprehensive mechanical properties was optimal when Co content was 8 wt%. The hardness, fracture toughness, and flexural strength were 19.87 GPa, 12.27 MPa m(1/2) and 1834 MPa, respectively. The cemented carbide fabricated in this paper are more excellent compared to the commercial cemented carbides.