Cutting performance and crack self-healing mechanism of a novel ceramic cutting tool in dry and high-speed machining of Inconel 718

The cutting performance of self-developed novel Al₂O₃-based ceramic tool (Al₂O₃/SiC_w/TiC_n) reinforced by SiC whisker and TiC nanoparticle was investigated experimentally in dry and high-speed machining of Inconel 718. Combining with the high-temperature mechanical properties and microstructure evolution of the tool material, the failure mechanism of the novel ceramic tool was revealed. The results showed that the novel ceramic tool can be used stably in dry machining of Inconel 718 at a high speed of 400 m/min. The service life of novel ceramic tool was 50% higher than that of the commercial Al₂O₃-based ceramic tool CC670 toughened by SiC whisker. The novel ceramic tool did not suffer from fracture failure and exhibited good resistance to flank wear and notch wear. For the tool failure mechanism, it shows that TiC nanoparticle improved the high-temperature hardness and high-temperature fracture toughness of tool materials, which was an important reason for the better wear resistance of novel ceramic tool. In the service conditions of dry and high-speed machining, the cutting temperature was as high as 1200 °C at which the SiC whisker was oxidized to form glassy phase. The crack of the tool was self-healed and the crack tip was passivated by glassy phase, which suppressed crack propagation to prevent fracture of the ceramic tool.