In-situ tensile damage and fracture behavior of original SiC fiber bundles, processed and uncoated SiC fiber bundles, SiC fiber bundle with PyC interphase, SiC/SiC minicomposites without/with PyC interphase are analyzed. Relationships between load-displacement curves, stress-strain curves, and micro damage mechanisms are established. A micromechanical approach is developed to predict the stress-strain curves of SiC/SiC minicomposites for different damage stages. Experimental tensile stress-strain curves of two different SiC fiber reinforced SiC matrix without/with interphase are predicted. Evolution of composite’s tangent modulus, interface debonding fraction, and broken fiber fraction with increasing applied stress is analyzed. For the BX™ and Cansas-3303™ SiC/SiC minicomposite with interphase, the composite’s tangent modulus decreased with applied stress especially approaching tensile fracture; the interface debonding fraction increased with applied stress, and the composite’s tensile fracture occurred with partial interface debonding; and the broken fiber fraction increased with applied stress, and most of fiber’s failure occurred approaching final tensile fracture.

分析了原始 SiC 纤维束、加工和未涂层 SiC 纤维束、具有 PyC 界面的 SiC 纤维束、无/具有 PyC 界面的 SiC/SiC 微型复合材料的原位拉伸损伤和断裂行为。建立了载荷-位移曲线、应力-应变曲线和微观损伤机制之间的关系。开发了一种微机械方法来预测不同损伤阶段的 SiC/SiC 微型复合材料的应力 - 应变曲线。预测了两种不同的 SiC 纤维增强 SiC 基体的实验拉伸应力 - 应变曲线，没有/有界面。分析了复合材料的切线模量、界面脱粘率和断裂纤维率随外加应力的变化。对于具有界面的 BX™ 和 Cansas-3303™ SiC/SiC 微型复合材料，复合材料的切线模量随着外加应力的增加而降低，尤其是在接近拉伸断裂时；界面脱粘率随外加应力的增加而增加，复合材料发生拉伸断裂，界面部分脱粘；并且断裂的纤维分数随着施加的应力而增加，并且大部分纤维的失效发生在接近最终拉伸断裂时。