In Situ Synthesis of MoSi2-SiC Composites by Two-Step Spark Plasma Sintering

The effect of different SiC doping content on the properties of MoSi2-based composites was analyzed in this study. The MoSi2-SiC composites were fabricated in situ by the SPS technique, utilizing self-synthesized carbon-containing Mo powder and Si powder as raw materials. A two-step sintering process was employed to ensure the formation of a uniform and dense composite structure. The microstructures and mechanical properties of these composites with various compositions were characterized. The results show that the composites were primarily composed of MoSi2, SiC, and a minor proportion of MoSiC phase. The introduction of SiC as a second phase was found to considerably enhance the mechanical properties of the MoSi2 matrix material. In particular, the MoSi2-26mol.%SiC sample exhibited Vickers hardness, fracture toughness, and flexural strength values of 16.1 GPa, 6.7 MPa<middle dot>m(1/2), and 496 MPa, respectively, corresponding to increases of 33%, 24%, and 28% compared to the pure MoSi2 material.