Study on Densification and Mechanical Properties of C_f/SiC Composites Prepared by PIP Method under Structural Regulation

Based on the PIP method, the effects of preform structural parameters on the pore distribution, densification process and mechanical properties of carbon fiber reinforced silicon carbide(C_f/SiC) composites were systematically investigated. The evolution mechanism of "rapid weight gain at the initial stage-slow saturation at the later stage" during the sintering process of composite materials was revealed through the statistics of sintering weight gain, macro/micro pore morphology observation and compression-bending property tests, and the exponential decay fitting model was established. The results indicate that the 34-layer specimens demonstrate significantly higher final weight gain rates(135%) during multiple sintering cycles, forming a homogeneous and dense structure that substantially enhanced the material's load-bearing capacity. In contrast, unreasonably structured bending specimens exhibit concentrated porosity due to infiltration limitations, resulting in reduced ultimate strength. This study establishes a comprehensive regulatory mechanism chain of structural parameters- infiltration/sintering-pore distribution-mechanical properties, providing both experimental evidence and theoretical support for PIP process optimization.