Fabrication of TiB_2/TiC Composites by Spark Plasma Sintering

TiB2/TiC composites were in situ fabricated through spark plasma sintering(SPS) technique using Ti and B4C powders as starting materials.The phase constituent of the samples was analyzed by X-ray diffraction techniques and microstructures were observed by scanning electron microscope.The Vickers hardness,fracture toughness and MSP strength at room temperature was measured by indentation method and Modified Small Punch(MSP) test.The results showed that the TiB2/TiC composite fabricated by one-step sintering(sintering at 1550℃ for 6 min) has an average grain size greater than 1 μm with MSP strength of 844 MPa.While the TiB2/TiC composite with an average grain size of about 200 nm could be fabricated by two-step sintering(at higher sintering temperature of 1550℃ and lower holding temperature of 1450℃) and its MSP strength reached as high as 1095 MPa.