双基体炭/炭复合材料的微观结构与力学性能

借助偏光显微镜、扫描电镜,透射电镜以及力学性能测试研究了微观结构对双基体炭/炭复合材料力学性能的影响.结果表明:基体炭在偏光显微镜下呈现光学各向异性,材料内部形成多层次的界面结构,热解炭呈现"皱褶状"片层结构,中间相沥青炭呈现片层条带状结构,基体炭片层的走向基本上平行于纤维轴向.材料受载破坏时裂纹通过改变扩展路径而延缓其扩展速度,在纤维-基体界面处以及基体炭片层之间引起滑移,在断口形貌上体现出锯齿状的断裂形式,材料具有韧性断裂的特征,抗弯强度最高可达223MPa.

Microstructure and Mechanical Properties of Dual-Matrix Carbon/Carbon Composites

Microstructures and mechanical properties of a 2D PAN fiber-reinforced dual-matrix C/C composites were studied with the aid of polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and mechanical testing experiments. Results show that the matrix carbon exhibits optical anisotropy under PLM. Multi-interface structure was formed inside the C/C composites. The pyrocarhon exhibits crinkle-like lamellar structure and the mesophase pitch carbon exhibits lamellar structure and its orientation is roughly parallel to the carbon fiber axis. The non-brittle fracture behavior of the composites is related to multiple crack deflections caused by the interface and micro-cracks within the matrix carbon layer. The flexural strength of composites is up to 223MPa.