Microstructure and mechanical properties of Si3N4–TiC nanocomposites

Si3N4–TiC nanocomposites are fabricated by hot press sintering from silicon nitride nanopowders and ultrafine TiC powders. The microstructure and mechanical properties are analysed and discussed. Scanning electron microscopy images show that the microstructure consists of equiaxed grains and grain boundary phase. The TiC added as a dispersed phase reacts with the nitrogen from Si3N4 during the liquid phase sintering, with the formation of TiC0.7 N0.3, trace of SiC and N2. The adding of a proper amount of TiC powders increases the flexural strength and has little influence on fracture toughness. The hardness increases with increasing TiC content.