Synthesis of TiC 0.5 –Al and Effect of Sintering Temperature on Mechanical Properties of PcBN Composites

Polycrystalline cubic boron nitride (PcBN) with excellent mechanical properties was sintered by using high activity TiC 0.5 and metal aluminum as binder at high temperature and pressure. The effects of sintering temperature on phase composition, microstructure, relative density and mechanical properties of PcBN composites were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy spectrum analysis. The results show that, under the conditions of low reaction temperature of 1400°C and holding time of 10 min, excellent composite properties of PcBN sintered material were obtained. The reinforced phases such as Ti(C, N), TiB 2 and AlN were stably presented in the sintered body. To be specific, the microhardness, flexural strength and fracture toughness of the sintered body first increased and then decreased with the increasing sintering temperature, as well as posessing a high fracture toughness, which were 39.74 GPa, 1217 MPa and 8.78 MPa m 1/2 , respectively.