Single fiber-tow minicomposites represent the major load-bearing element of woven and laminate ceramic matrix composites (CMCs). To understand the effects of fiber type, fiber content, and matrix cracking on tensile creep in SiC_f/SiC CMCs, single-tow SiC_f/SiC minicomposites with different fiber types and contents were investigated. The minicomposites studied contained either Hi-Nicalon™ or Hi-Nicalon™ Type S SiC fibers with a boron nitride (BN) interphase and a chemical-vapor-infiltrated-silicon-carbide (CVI-SiC) matrix. Tensile creep was performed at 1200 °C in air. A bottom-up creep modeling approach was applied where creep parameters of the fibers and matrix were obtained separately at 1200 °C. Next, a theoretical model based on the rule of mixtures was derived to model the fiber and matrix creep-time-dependent stress redistribution. Fiber and matrix creep parameters, load transfer model results, and numerical modeling were used to construct a creep strain model to predict creep damage evolution of minicomposites with different fiber types and contents.

单纤维丝束微复合材料代表机织和层压陶瓷基复合材料（CMC）的主要承重元素。要了解SiC _f / SiC CMC，单丝SiC _f中纤维类型，纤维含量和基体开裂对拉伸蠕变的影响研究了具有不同纤维类型和含量的/ SiC微型复合材料。所研究的微型复合材料包含Hi-Nicalon™或Hi-Nicalon™S型SiC纤维，具有氮化硼（BN）相间和化学气相渗透碳化硅（CVI-SiC）基体。在空气中于1200°C进行拉伸蠕变。采用了自下而上的蠕变建模方法，其中分别在1200°C下获得了纤维和基体的蠕变参数。接下来，推导了基于混合物规则的理论模型，以模拟纤维和基体蠕变时间相关的应力再分布。利用纤维和基体的蠕变参数，载荷传递模型结果和数值模型来构建蠕变应变模型，以预测具有不同纤维类型和含量的微型复合材料的蠕变损伤演化。