基体含量对炭/炭复合材料的影响

来源期刊：中南大学学报(自然科学版)2002年第1期

论文作者：吴凤秋 熊翔 巩前明 刘根山 王林山

文章页码：56 - 59

关键词：炭/炭复合材料;树脂炭;损伤机理;力学性能

Key words：C/C composites; resin carbon; damage mechanism; mechanical properties

摘    要：研究了最终密度为1.85~1.86 g/cm³的二维(2D)炭/炭复合材料的不同基体成分———CVD炭和树脂炭的含量对2D C/C复合材料力学性能的影响;并在扫描电镜下进行断口分析,探索了C/C复合材料的损伤机理.此外,通过观察炭纤维与CVD炭以及CVD炭与树脂炭的结合状态、纤维拔出、韧断等断口微观形貌,从微观上分析了不同基体炭以及它们的微观结合对2D C/C复合材料强度性能的影响.结果表明:CVD炭含量越高,剪切强度越低;而抗弯强度、弯曲弹性模量和抗压强度则先增加后降低,有一个明显的起伏,说明CVD炭与树脂炭的含量有一个最佳配比,即CVD炭含量约为44%时,可以使2D C/C复合材料力学性能得到最佳值;炭纤维与CVD炭成树脂炭粘结并不是特别牢固,其界面具有缓冲裂纹传播速度或改变裂纹传播方向的作用,或界面剥离吸收掉集中的应力,从而使炭纤维的强度得到很好的利用,C/C复合材料的强度得以提高.

Abstract: The effect of the ratio of different matrix carbon on the mechanical properties of two-dimensional carbon-carbon composites with the final density of 1.85~1.86 g/cm³was studied. The fracture morphology was investigated by a scanningelectron microscope(SEM), and the damage mechanism of 2D carbon-carbon was analyzed further. The results demonstrate that the higher the content of CVD carbon, the lower the shear strength, and that while the bending strength,the bending modulus and compressive strength increase initially and then decrease, showing an obvious flux .The resultdemonstrates that there is an optimal ratio of about 44% CVD carbon to the whole matrix carbon, so that 2D C/C composites’best mechanical properties can be obtained. Additionally, the feature of the fracture morphology of three groups of samples are analysed in the paper, mainly about the bonding state of carbon fiber and CVD carbon, or CVD carbon and resin carbon, so that we can draw a conclusion that the bond is not so firm that, to some extent, the interface can bumper the spreading speed, or change the directions of these cracks, or even absorbing the concentrated stress by peeling off; thus the strength of the carbon fiber is well utilized and in the end the strength of 2D C/C composite is increased.