先驱体转化Cf/SiC复合材料的热膨胀行为研究

摘要

The thermal expansion of Cf/SiC composites fabricated by precursor inifltration and pyrolysis was studied. The results showed that the coefifcient of thermal expansion of Cf/SiC composites was related to the microstructure of the composites. Because the crystallization of SiC matrix derived from precursor pyrolysis was low, the coefifcient of thermal expansion (CTE) of Cf/SiC composites was low. At the same time, because the axial CTE of carbon ifber was lower than that of SiC matrix, along x dimension, the CTE of 3D Cf/SiC composites was lower than that of 2D Cf/SiC composites, and the CTE of 2D Cf/SiC composites along x dimension was lower than along z dimension.%研究了先驱体转化Cf/SiC复合材料的热膨胀行为。结果表明，先驱体转化Cf/SiC复合材料的热膨胀系数主要与材料结构组成有关。先驱体转化工艺生成的SiC基体结晶程度较差，导致先驱体转化Cf/SiC复合材料热膨胀系数较低。同时由于碳纤维轴向热膨胀系数明显低于碳纤维径向和SiC基体，3D Cf/SiC复合材料x向热膨胀系数低于2D Cf/SiC复合材料；而2D Cf/SiC复合材料x向热膨胀系数又明显低于z向。