In situ synthesis of Ti₃SiC₂/SiC composite by displacement reaction of Si and TiC

In situ synthesis technology was adopted to fabricate SiC reinforced Ti₃SiC₂ composite by displacement reaction of Si and TiC powders. The formation of SiC particles as reinforcements with elongated or equiaxed shape distributed in Ti₃SiC₂ matrix. The average size of SiC equiaxed particles was about 2 μm and that of elongated ones was in the range of 5-8 μm in length and 2 μm in width. TiC with about 1 μm in size was also found in the composite. The particles of SiC or TiC inhibited the grain-boundary migration of Ti₃SiC₂ resulting in a fine Ti₃SiC₂ matrix with a grain size of 10 μm. Differential scanning calorimetry showed that Si reacted drastically with TiC at 1340 °C with release of heat. The presence of TiC in the Ti₃SiC₂/SiC composite should be attributed to decomposition of Ti₃SiC₂ at 1500 °C rather than the loss of Si during reaction process that resulted in unreacted TiC left. Reaction paths in the present experiment were postulated on the basis of Ti-Si-C system and reaction model of Mo₂C-Si to understand the mechanism of the formation of Ti₃SiC₂ and SiC.