基体改性对碳纤维增韧碳化硅复合材料结构与性能的影响

采用化学气相浸渗法对2D C/SiC复合材料进行基体改性,制备了二维碳纤维增韧碳-碳化硅二元基复合材料(two dimensional carbon fiber reinforced C-SiC binary matrix composites,2D C/C-SiC).2D C/C-SiC复合材料的基体为热解碳和碳化硅交替叠层的多层基体.研究了2D C/C-SiC复合材料的微观结构,比较了2DC/SiC复合材料和2DC/C-SiC复合材料的力学性能及断口形貌.结果表明:2DC/C-SiC复合材料可在基本保持2DC/SiC复合材料抗弯强度的基础上,其断裂韧性得到显著提高.基体改性的效果明显.纤维的逐级拔出是断裂韧性提高的原因.

INFLUENCE OF MATRIX MODIFICATION ON MICROSTRUCTURE AND PROPERTIES OF CARBON FIBER REINFORCED SILICON CARBIDE COMPOSITES

Two-dimensional carbon fiber-reinforced C-SiC binary matrix composites (2D C/C-SiC) with PyC/SiC alternative multi- layered matrix were fabricated by chemical vapor infiltration to modify the matrix of 2D C/SiC composites. The microstructure and fracture surface of 2D C/C-SiC composites were investigated, and their mechanical properties were compared to those of 2D C/SiC composites. It is shown that the fracture toughness of 2D C/C-SiC composites is greatly higher than that of 2D C/SiC composites, whereas their flexural strength is approximately the same. The efficiency of matrix modification of 2D C/SiC composites is evident. The improved fracture toughness is due to the multi-stage pull-out of fibers.