Enhanced Performance in Si3N4 Ceramics Cutting Tool Materials by Tailoring of Phase Composition and Hot-Pressing Temperature

In this study, a type of micro-nano Si3N4matrix ceramic cutting tool material was successfully prepared by controlling the addition amount of TiC0.7N0.3and the hot-pressing sintering temperature. The effects of different volume fractions of TiC0.7N0.3on the microstructure, mechanical properties, particle size distribution, and relative density of Si3N4ceramic tools at the same temperature were investigated. The results show that the addition of TiC0.7N0.3makes the β-Si3N4grains with different diameters and aspect ratios interlaced and tightly bonded, thus achieving the strengthening and toughening effects. In addition, the effects of different hot-press sintering temperatures on the properties of Si3N4ceramic tool materials were studied. It was concluded that the density of the material increased with the increase of the hot-pressing temperature. The relative density, flexural strength, and fracture toughness of the samples with 1 vol% TiC0.7N0.3added at 1750 °C and 30 MPa pressure reached 99.22%, 993 MPa, and 9.81 MPa·m1/2, respectively.Keywords:Si3N4;ceramic cutting tool;hot-pressing sintering;TiC0.7N0.3;self-toughening