Microstructure of Ti₅Si₃–TiC–Ti₃SiC₂ and Ti₅Si₃–TiC nanocomposites in situ synthesized by spark plasma sintering

Nanostructured Ti₅Si₃–TiC–Ti₃SiC₂ and Ti₅Si₃–TiC composites were in situfabricated through the spark plasma sintering (SPS) technique using Ti and SiC powders as reactants. It was found that the composites could be prepared in arelatively short time (6 min at 1260 °C) above 98% theoretical density. The phase constituents and microstructures of the samples were analyzed by x-ray diffractionand observed by scanning electron microscopy. Transmission electron microscopywas used for detailed microstructural analysis. The results showed that the reaction products mainly consisted of Ti₅Si₃ and TiC phases or Ti₅Si₃, TiC and Ti₃SiC₂phases, depending on the molar ratio of reactants (Ti to SiC). The composites exhibited fine microstructure; TiC grain size was less than 200 nm. Fracturetoughness at room temperature was also measured by indentation tests.