整体毡碳/碳复合材料的高温剪切性能研究

Shear Properties of Integral Felt C/C Composites at Elevated Temperatures

运用双槽口剪切试验方法测试了碳纤维增强碳基复合材料(C/C)在室温、700℃、1000℃、1400℃下的剪切强度,并用扫描电子显微镜(SEM)观察了材料的原始组织形貌和断口微观形貌。结果表明:材料的剪切强度在一定范围内随温度的升高而增加,材料Z向的剪切强度优于XY向。通过SEM观察分析可知,材料XY向和Z向纤维的含量明显不同;室温下,C/C复合材料的破坏形式有纤维拔出及断裂,而高温下,失效形式主要为纤维的拔出、纤维/基体界面脱粘等。

Shear strength of a carbon fibre-reinforced carbon composite （C/C） was investigated by means of compression of double-notched specimen （DNS） at room temperature, 700℃, 1000℃ and 1400℃ respectively. The microstructure and the fractured morphologies of the specimens failed by the shear loading were observed by a scanning electron microscope （SEM）. The results show that the shear strength of the C/C increase with the rise of temperature in a certain range, and the shear strength in Z direction is higher than that in XY. It is indicated that the fibre content of C/C is different in XY and Z direction from the SEM photographs. At room temperature, for C/C composite mate- rials, the damage manners include the pulling out and rupture of fibre, however, at elevated temperature, the main failure forms are the fibre pullout and the debonding of the interface between fibers and matrix：