2D C/C复合材料微观结构与力学性能的研究

采用等温化学气相渗透方法,通过调整沉积工艺,制备了具有不同微观组织结构的2D C/C复合材料.利用偏光显微镜(PLM)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)结合选区电子衍射(SAED),研究了热解炭基体微观组织结构,借助万能试验机测试了材料的三点弯曲性能.结果表明:层状高织构(HT)热解炭基体占优时C/C复合材料表现为假塑性断裂;扁平片状中织构(MT)热解炭与颗粒状各向同性层热解炭(ISO)有利于提高材料的弯曲强度;HT基体与炭纤维界面结合良好,界面处不存在非HT织构,但取向角(OA)略有增大.

Study on the Microstructures and Mechanical Properties of 2D C/C Composites

The 2D C/C composites with different microstructures were fabricated by isothermal-isobaric chemical vapor infiltration (ICVI). The mechanical properties of the 2D C/C composites were investigated by 3-point bending tests. The microstructures of the pyrocarbon matrix were observed by polarized light microscope (PLM), scanning electron microscope (SEM), transmission electron microscope (TEM) combining selected area electron diffraction (SAED). The results show that 2D C/C composites with dominant layered-HT pyrocarbon matrix exhibit a pseudo-plastic failure behavior. The flake-like fragments MT and granular-like particles ISO are in favor of increasing the flexural strength of the materials. It exists a good interfacial bonding between the fiber and HT layer. The non-HT layer does not exist at the interface, but the orientation angle (OA) of the matrix slightly increases.