The application prospects of Ti(C,N) metallic ceramic cutting tool materials

Ti(C,N) metal-ceramic is a ceramic-metal composite material, with its hardness and heat resistance close to that of ceramics while its flexural strength and fracture toughness are higher than those of ceramics. The thermal conductivity, heat resistance, adhesion resistance and chemical stability of Ti(C,N) metal-ceramic are much better than those of high-speed steel, so it has been applied in cutting tool materials.

Compared with TiC metal-ceramic, Ti(C,N) metal-ceramic has higher high-temperature strength and hardness, good thermal conductivity, and excellent impact resistance and other comprehensive properties. Compared with traditional WC-Co hard alloy, Ti(C,N) metal-ceramic is particularly suitable for high-speed cutting and for fine and semi-fine processing of materials due to its high red hardness, good high-temperature oxidation resistance and high thermal conductivity, etc.

The Ti(C,N) metal-ceramic material is an ideal material for replacing WC-based hard alloy in the future, but the main factors restricting the application of Ti(C,N) metal-ceramic materials as high-performance cutting tools are strength, heat fatigue resistance, reliability and high-temperature stability. Domestic researchers have taken the following measures to improve the above-mentioned properties of Ti(C,N) metal-ceramic materials:

(1) Microstructure ultrafine-grained, that is, grain ultrafine-grained, to improve the strength and toughness of the material;

(2) Through component optimization, adding TaC, NbC and other carbides to Ti(C,N) metal-ceramic materials and improving the stability of the interface between the two phases of metal ceramics, thereby improving the red hardness and thermal shock resistance of the material;

(3) Performing surface boronizing treatment on the manufactured ultrafine-grained metal ceramic cutting tools to further improve the surface wear resistance and reliability of the cutting tools;

(4) Developing coated metal ceramic cutting tools.
As of 2010, the market capacity of metal cutting tools in China has reached 33 billion yuan. However, most of the cutting tools produced in China still belong to low-end high-speed steel standard cutting tools, and the proportion of domestic metal ceramic cutting tools in the market is still relatively low. According to the requirements of the "Twelfth Five-Year Plan for the Tool Industry", the market share of domestic cutting tools in the high-end market should be increased from the current 15% to 30%-40%, and it will take 2-3 five-year plans to gradually increase the domesticization rate to the average level of developed countries, that is, 60%-70%. To achieve this goal, the average annual growth rate of high-end cutting tools in China should reach about 20%. At present, domestic cutting tools are still mainly high-speed steel tools. With the rapid development of high-speed cutting technology and numerical control technology, it is necessary to develop high-performance and long-life metal ceramic cutting tools. It is certain that as the strength and toughness of Ti(C,N) metal-ceramic cutting tool materials continue to improve, the share of Ti(C,N) metal-ceramic cutting tools in the hard cutting tool market will gradually expand and there will be a trend of replacing tungsten carbide/cobalt hard cutting tools.

In conclusion, the main problem restricting the large-scale application of Ti(C,N) metal-ceramic composite materials in high-end cutting tools is the insufficient strength and toughness of the material. Currently, domestic research groups and production units have listed the strengthening and toughening of Ti(C,N) metal-ceramic composite materials as the most important research topic. The research and development of structurally uniform ultrafine-grained metal ceramic composite materials is of great significance for promoting the renewal and technological progress of high-end hard cutting tools in China.