中文摘要：

采用3D炭纤维预制体，以丙烯作为碳源，氮气作为载气，利用自制的快速CVI炉制备了C／C复合材料。详细分析了不同CVI工艺下，热处理对C／C复合材料断裂强度、断裂方式以及材料均匀性的影响。力学性能测试结果表明，材料的弯曲断裂特征与制备过程中受到的高温热处理次数有关。与1次连续CVI工艺相比，多阶段连续CVI工艺下，C／C复合材料经过2次“CVI-热处理”循环工艺后，其密度达1．8g／cm^3，抗弯强度达196．69MPa，断裂方式为假塑性断裂，材料在Weibull概率分布下强度分散性较小。

英文摘要：

Using 3D carbon fibre preform, with C3H6 as the carbon source and N2 as the carrier gas, C/C composites are fabricated by the fast CVI process. The effects of heat-treatment on flexural strength, fracture ways and the uniformity of C/C composites are analyzed under different CVI processes. The experimental results indicate that the fracture characteristics of composites are closely related to the times of heat-treatment during CVI process. Compared with a continuous CVI, C/C composites show a pseudo-plastic fracture with the destiny 1.8 g/cm3 and flexural strength 196.69 MPa after two ＂CVI-heat treatment＂ circulation under multi-stage CVI process, and the uniformity of materials is well by Weibull distribution.