Microstructure and mechanical properties of TiC–TiN based cermets for tools application

The objective of this work is to develop materials with both a good hardness and a good toughness. Titanium carbonitride has a significant hardness (2000Hv), but its toughness (6 MPa√m) is insufficient for tools applications. Toughness can be improved by addition of a metallic binder. Cermets based on TiC and TiN with Ni as binder are the most developed materials. In the present work, the effect of TiN addition and binder content on the microstructure and the properties of the TiC based cermets elaborated by pressureless sintering have been investigated.Results show that dense cermets with specific core/rim structure have been obtained. The rupture strength and the toughness increase with the addition of Ni. The optimum values of mechanical properties were found for the cermet with 15 wt% Ni and 10 wt% TiN addition, respectively, which exhibits a Vickers hardness over 1400Hv0.31400Hv0.3 and a fracture toughness around 13.6 MPa√m.