Effect of WC content on the microstructure and mechanical properties of TiCN-HfN cermet tool materials

TiCN-HfN-WC cermet tool materials were fabricated by hot-pressed sintering technology, and the effect of WC mass fraction on the microstructure and mechanical properties of the cermet tool materials was investigated. The results show that, the TiCN-HfN-32%WC cermets are composed of TiCN, (Ti, Hf, W)(C, N), WC, and MoNi, which also contain a little amount of (Ti, Mo, W)(C, N), and the retiform skeleton structure forms inside the cermet material. With the increase of the WC content, TiCN grain becomes smaller, which indicates that WC can inhibit the TiCN grain growth and achieve the refinement of TiCN grain; meanwhile, the density, hardness, and fracture toughness of the TiCN-HfN-WC cermet also increase first and then decrease, however, the flexural strength increases gradually. When the WC mass fraction is 32%, the TiCN-HfN-WC cermet shows good comprehensive mechanical properties: the hardness is 20.2 GPa, the fracture toughness is 7.1 MPa·m^1/2, and the flexural strength is 1581.3 MPa.