Synthesis, Structure, and Properties of SiC–TiC–Ti3SiC2–TiSi2 Composites Obtained by Spark Plasma Sintering

SiC–TiC–Ti3SiC2–TiSi2 composites were obtained by spark plasma sintering of pure SiC powder with 20–40 vol % Ti3SiC2 MAX phase addition. The influence of sintering parameters, including temperature, compaction pressure, and isothermal holding time, on the phase composition, microstructure and mechanical properties of the materials was studied. X-ray powder diffraction results showed that Ti3SiC2 decomposes at 1400°C, while sintering at temperatures up to 1100–1300°C allows obtaining up to 100% of the Ti3SiC2 product. The microstructure of the sintered composites is characterized by high open porosity 43–68%; the phase composition consists of SiC particles with inclusions of the Ti3SiC2–TiC–TiSi2 composite. Flexural strength varies in the range of 7–62 MPa and depends on porosity and TiC content: the maximum value of 62 MPa was achieved for composites sintered at 1250°C, with an open porosity of 45% and a TiC content of 33 vol %. Fracture of the composites occurs via an intercrystalline mechanism, which is confirmed by the analysis of fracture surface images.