Fabrication and characterization of Ti(C,N)-based micro-laminated ceramic tool with thermal barrier function by two-step hot-pressing sintering process

Ti(C,N)-based cermet tools are confronted with the issues of insufficient strength and low mechanical properties at high cutting temperatures. In order to break through the bottleneck of the high-temperature performance of cutting tools, based on the concept of integrated structure-function design, this study designed a micro-laminated structure and introduced a composite phase with a low thermal conductivity coefficient to construct a thermal barrier layer on the surface of Ti(C,N)-based materials. By adjusting the content of WC in the matrix layer and adopting a two-step hot-pressing sintering process, the synergistic enhancement of the mechanical properties of the surface and matrix layer materials were achieved. The Vickers hardness of TWAZ2 tool material was 19.90 GPa, the fracture toughness was 9.45 MPa·m^1/2, and the flexural strength was 950.81 MPa. It demonstrated excellent high-temperature hardness and wear resistance, maintaining a hardness of 12.23 GPa at 1000 ℃. Furthermore, a method for quantitatively characterizing the thermal barrier efficiency of the thermal barrier layer was proposed. The results showed that the temperature and heat flux density of tool materials with thermal barrier function were all reduced under the same thermal load conditions. In the laminated structure with thermal barrier function, the thermal shielding characteristics of the surface layer and the heat dissipation mechanism of the matrix layer form a synergistic effect, which played a positive role in prolonging the service life of the cutting tool. This research provides a new insight into the design and preparation of new tool materials considering the thermal-mechanical coupling effect.