The effect of heat treatment on the microstructure and performance of Cansas 3303 SiC fiber bundles and SiC/SiC composites with BN interphase, prepared by CVI or RMI, are investigated. Additionally, the tensile properties and fracture behavior at different temperature of CVI or RMI SiC/SiC composite are examined. Unconstrained SiC fiber bundles stable below 1350°C, halving at 1450°C and further decreasing with temperature rises. In the composites, however, the interphase and matrix exert compressive stress on fibers, mitigating their performance decline. The microstructure of interphase is mainly affected by heat treatment temperature. Tensile strength of both composites decreases with temperature. Both composites maintain structural stability with minimal changes in flexural properties below heat treatment at 1200°C. The flexural strength decreases with further rising heat treatment temperature and time. The mechanisms of properties degradation in both composites are discussed and a method for studying the thermal stability of SiC/SiC composites is established.

中文翻译：

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采用 Cansas 3303 SiC 纤维的 CVI 和 RMI SiC/SiC 复合材料的热稳定性


研究了热处理对 Cansas 3303 SiC 纤维束和采用 CVI 或 RMI 制备的 BN 界面 SiC/SiC 复合材料的微观组织和性能的影响。此外，还研究了 CVI 或 RMI SiC/SiC 复合材料在不同温度下的拉伸性能和断裂行为。无约束的 SiC 纤维束在 1350°C 以下稳定，在 1450°C 时减半，并随着温度的升高而进一步减少。然而，在复合材料中，相间和基体对纤维施加压应力，缓解了其性能下降。界面的微观结构主要受热处理温度的影响。两种复合材料的拉伸强度都随温度的升高而降低。两种复合材料都保持了结构稳定性，在 1200°C 热处理后弯曲性能的变化很小。 弯曲强度随着热处理温度和时间的进一步升高而降低。讨论了两种复合材料性能退化的机理，并建立了研究 SiC/SiC 复合材料热稳定性的方法。