【摘要】 为了提高传统等温化学气相渗透(ICVI)工艺的致密化效率,降低C/C复合材料生产成本,本文通过减小预制体周围气体流动空间,将传统负压ICVI工艺加以改进．采用改进后的新型ICVI工艺,在沉积温度1100℃、沉积压力为常压和滞留时间为0．1s的实验条件下,以甲烷为前驱体,氮气为稀释气体,对纤维体积分数为28．7％的2D针刺炭毡预制体进行致密化研究,采用偏光显微镜观察所制试样的组织结构,测定了其三点弯曲强度,并利用SEM观察断面形貌．结果表明：125h制备出密度为1．73g/cm~3且密度分布均匀的C/C复合材料．试样的组织结构为粗糙层,弯曲强度为250．87MPa,模量为29．29GPa,断裂行为呈现明显假塑性．更多还原

【Abstract】 In order to enhance densification efficiency and decrease the costs of preparation,a novel isothermal chemical vapor infiltration process for fabrication C/C composites was developed by decreasing the space of around preforms in the conventional hot wall reactor.With volume fraction of 28.7%,and infiltrated by the novel ICVI at ambient pressure and 1100℃,residence time of 0.1s,and methane as precursor,nitrogen as diluted gas,the 2D fiber felt preform was densified. The texture of the obtained sample was investigated by using a polarized light microscope and the flexural stength was determined by three-point bonding tests,after the tests,the morphology of the fracture surface was observed by using SEM.The resuts show that the bulk density of the C/C composite prepared in 125h is 1.73g/cm~3,and the density distribution is uniform.Its texture is pure rough laminar.Its flexural strength is 250.87MPa.Its flexural modulux is 29.29GPa.The C/C composite exhibits a pseudo-plastic failure behavior.更多还原