The mechanical behavior and oxidation resistance of SiC/SiC-SiBC composites were studied in this work. According to the debonding criterion of He and Hutchinson, the debonding could occur at the BN interphase, which insures that the fibers can well play the strengthening and toughening performance. The oxidation resistance of SiC/SiC-SiBC composites consisting of SiC fibers with thermal expansion coefficients (CTE) of 5.1 × 10⁻⁶ K⁻¹ and 4.0 × 10⁻⁶ K⁻¹ was compared. The composites consisting of SiC fibers with higher CTE show slight weight changes at 800, 1000, and 1200 °C, and the corresponding strength retention ratios are 109.6%, 103.2% and 102.9%, exhibiting excellent oxidation resistance. The CTE of composites consisting of SiC fibers with higher CTE matches well with the CTE of SiC coating, so rarely no cracks can be formed in the coating, which inhibits the inward diffusion of oxidizing medium and leads to high strength retention ratios after oxidation tests.

研究了SiC / SiC-SiBC复合材料的力学行为和抗氧化性能。根据He和Hutchinson的脱粘准则，脱粘可能发生在BN相间，这确保了纤维能够很好地发挥增强和增韧性能。由热膨胀系数（CTE）为5.1×10 ^-6  K ^-1和4.0×10 ^-6  K ^-1的SiC纤维组成的SiC / SiC-SiBC复合材料的抗氧化性进行了比较。由具有较高CTE的SiC纤维组成的复合材料在800、1000和1200°C时表现出轻微的重量变化，相应的强度保持率分别为109.6％，103.2％和102.9％，表现出优异的抗氧化性。由具有较高CTE的SiC纤维组成的复合材料的CTE与SiC涂层的CTE很好地匹配，因此涂层中几乎不会形成裂纹，这抑制了氧化介质的向内扩散，并导致在氧化测试后具有较高的强度保持率。