准三维C/C复合材料的压缩性能及其破坏机理

以炭纤维针刺毡为预制体,分别采用CVI法和CVI与结合液相法相结合的方法制备热解炭、树脂炭和沥青炭基质的准三维C/C复合材料,并研究了这些材料的压缩性能及其破坏机理。研究结果表明:压缩强度随致密度提高而增大;炭基体对压缩强度的影响从大到小依次为CVI炭,树脂炭和沥青炭;树脂炭的垂直压缩强度与CVI炭的垂直压缩强度相近,两者都高于沥青炭;3类基质炭试样的压缩破坏均表现为韧性断裂方式,其中平行压缩主要以分层劈裂的方式破坏,致密度较低的试样垂直压缩呈现出压溃破坏,致密度较高的试样垂直压缩表现为剪切破坏或分层破坏。

Compressive Properties and Fracture Mechanism of Quasi-3D C/C Composites

The quasi-3D C/C composites with liquid pitch carbon and resin carbon were fabricated by way of CVI and the combination of CVI and liquid phases with needled felt as preform. Their compressive properties and fracture mechanism were studied. The results show that the compressive strengths of C/C composites is the hightest with pyrolytic carbon, at the middle with the resin carbon and the lowest with pitch carbon. As for the vertical compressive strength, resin carbon is similar to pyrolytic carbon but larger than pitch carbon. C/C composites with different matrix carbon show toughess fracture mechanisms ,and the parallel compressive specimens were destroyed by delamination split , the vertical compressive specimens of C/C composites with low density were crushed , but the higher one were destroyed by shear stress or delamination.