The Influence of the Weaving Architecture of Fiber Preforms on the Mechanical Behavior of SiC/SiC Composites

SiC/SiC composites with different weaving architectures were prepared by the polymer precursor impregnation and pyrolysis process. The microstructure of the SiC/SiC composites was tested by SEM technology, and mechanical properties were evaluated through flexural properties, tensile properties and fracture toughness.The study demonstrated that the tensile modulus of SiC/SiC composites aligns with the fiber-to-binder volume fraction distribution principle. Both warp and weft orientation significantly influence mechanical strength, primarily due to the fiber volume fraction in load-bearing directions and their ability to resist external loads through buckling deformation. In general, the SiC/SiC composites with fibers plied in both the warp and weft directions exhibit the best comprehensive mechanical properties. The tensile strength, flexural strength, and fracture toughness are 340.40 MPa, 501.03 MPa, and 27.80 MPa·m 1 / 2 in the warp direction, and 199.92 MPa, 420.78 MPa, and 22.81 MPa·m 1 / 2 in the weft direction respectively. However, the weft-direction bending fracture behavior of SiC/SiC composites exhibits weak pseudoplastic characteristics with high variation in flexural strength. This phenomenon is mainly attributed to the high resistance and rapid propagation of crack growth, as well as insufficient stress release mechanisms such as crack deflection, fiber bridging, and fiber pull-out due to the synchronous fracture of weft fibers.