The influence of components on the high-temperature performance and cutting performance of Si3N4-based ceramic tools

Abstract

Three kinds of Si₃N₄-based ceramic tools (single-phase Si₃N₄, Si₃N₄/(W,Ti)C, and Si₃N₄/(W,Ti)C/Ni) were fabricated by microwave sintering. The phase composition, toughening mechanism, mechanical properties at room and high temperatures (800°C), and cutting performance of Si₃N₄-based ceramic tool materials with different additives were investigated. The results showed that the addition of (W,Ti)C and Ni had a significant effect on improving the mechanical properties at room temperature, although it reduced the phase transition conversion rate of Si₃N₄. Si₃N₄/(W,Ti)C tools had good high-temperature stability, while Si₃N₄/(W,Ti)C/Ni tools had a decrease of about 31.6% in high-temperature hardness and a decrease of 13.7% in high-temperature flexure strength. Under the premise of ensuring a certain level of fracture toughness, high-temperature hardness is the main influencing factor on the cutting life of cutting tools. The Si₃N₄/(W,Ti)C tools exhibit superior cutting performance whose cutting life reaches to 50.67 min which was 1.37–3.27 times longer than the other two ceramic cutting tools at the same cutting parameters when continuous dry cutting T10A. In addition, high-temperature flexure strength limits the choice of cutting speed, and lower high-temperature flexure strength can lead to rapid tool failure.