Effects of Ti(C, N) addition on the microstructure and mechanical properties of spark plasma sintered Si3N4/Ti(C, N) ceramic tool material

Abstract Si3N4/Ti(C, N) ceramic tool materials were investigated in this work. The effects of Ti(C, N) addition and sintering temperatures on the mechanical properties, phase transformation, and microstructures of Si3N4/Ti(C, N) ceramic tool materials were considered. Ti(C, N) addition promoted the densification and phase transformation, especially at low sintering temperatures. The optimum mechanical properties could be obtained by addition of 10 wt% Ti(C, N) at 1650 °C. Its relative density, Vickers hardness, and fracture toughness were found to be 99.76 ± 0.07 %, 17.11 ± 0.38 GPa and 7.35 ± 0.64 MPa m1/2, respectively. The microstructure of Si3N4/Ti(C, N) was uniform and no abnormal grain growth could be observed. The increase in fracture toughness was attributed to the combination of pulling-out of β-Si3N4, crack-bridging, and crack-deflection.