两种炭基C/C复合材料的微观结构及弯曲性能对比

Comparison of microstructure and flexural property of C/C composites with two kinds of carbon matrices

采用偏光显微镜、扫描电镜和万用电子力学试验机对比研究了由无纬布/网胎结构碳毡增强的沥青炭和热解炭基C/C复合材料(分别简称材料A和材料B)的微观结构及弯曲性能。结果表明,材料A中的沥青炭呈连续性较好的细薄片层结构,层间具有大量裂纹,结合力较弱;材料B中,热解炭由大量生长锥构成,在SEM下表现为厚度较大的片层结构,层间结合力强。材料A在XY方向的弯曲强度略低于材料B,但在Z方向高于后者。前者在2个方向均表现出较好的假塑性断裂,后者在XY向为"阶梯型"断裂,Z向为脆性断裂。材料的弯曲力学行为与炭基体微观结构和碳毡内孔隙填充状况密切相关。

The microstructure and flexural property of C/C composites with pitch and pyrocarhon matrix（ named as material A and B respectively）reinforced by non-woven cloth/network carbon felts were comparatively studied by polarized light microscope, scanning electron microscope and universal mechanical property machine. The results show that, for material A, the pitch carbon ma- trix is of continuous tiny laminar structure with numerous inter-laminar micro-cracks, resulting in the weak bond among laminas ; for material B, pyrocarbon matrix eonsits of amounts of growth-cones, and similarly displays thick laminar structure under SEM while the bond among laminas is strong. The XY-directional flexural strength of material A was slightly lower than that of material B, but the Z- directional strength was higher. The material A presented ideal pseudo-plastic fracture characteristic in both XY and Z directions, and the material B exhibits＂ladder type＂ fracture characteristic in XY-direction and obvious brittle fracture in Z-direction. The flex- ural mechanical behavior of material was greatly related to the microstructure of carbon matrix and the pore filling in carbon felt.