碳/碳复合材料中不同微区的基体结构

为优化碳基体结构,提高碳/碳(C/C)复合材料综合性能,针对沥青基C/C复合材料中纤维束内及纤维束间不同碳基体结构微区,利用显微Raman光谱、原位纳米力学测试、Micro-CT、扫描电镜(SEM)和压汞仪对碳基体结构进行研究。结果表明:碳基体呈片层结构沿纤维、纤维束表面取向堆积排列,在纤维、纤维束表面区域及纤维束之间碳基体中存在一定孔隙、裂纹等缺陷;纤维间基体的石墨化程度是沿着纤维表面向中心区域逐步增强,靠近纤维表面区域基体的弹性模量高于纤维间区域的弹性模量。C/C复合材料中碳基体形成过程存在渐次性和差异性,从而影响C/C复合材料综合力学性能。

Matrix structure of different microzones in carbon / carbon composites

This paper seeks to study the structure of carbon matrix and thereby reveal forming mechanism as part of on-going efforts to optimize carbon matrix structure and improve the comprehensive performance of carbon / carbon（ C / C） composites. The study draws on the presence of carbon matrix of different microzones in fiber bundle and in fiber bundles of pitch-based C / C composites and uses micro raman spectroscopy,in situ nanomechanical testing,Micro-CT,scanning electron microscopy（ SEM） and mercury intrusion tester. The results show that carbon matrix is of lamellar structure tending to pack along fiber,and fiber bundle surface,leaving carbon matrix subject to defects,such as pores and cracks in fibers,fiber bundles and on fiber surface area; the matrix in fibers has a gradually increasing graphitization degree from the fiber surface to the central area,allowing substrate to have a higher elastic modulus near the fiber surface area than between fiber area. The paper concludes that the formation of carbon matrix for C / C composites is accompanied by sequence and difference,with a consequent effect on comprehensive mechanical properties.