C/C复合材料高温长时烧蚀行为与控制方法

熊翔

摘 要：利用化学气相渗透法在三维细编穿刺炭毡中的炭纤维表面沉积TaC陶瓷界面，通过控制气体在预制体中的流动方向，获得梯度分布TaC界面改性C/C复合材料。研究了材料的微观结构、弯曲性能以及断裂韧性，结果表明：TaC呈层状分布在炭纤维表面，从C/C复合材料表层到内部，TaC陶瓷相的含量呈梯度分布；梯度分布TaC界面改性C/C复合材料的平均弯曲强度为272.6 MPa，平均断裂韧性为5.0 MPa·m1/2；整体上，沿材料厚度（Z轴）方向，随TaC含量的降低，纤维的拔出长度明显变短；在表层富TaC区，TaC含量对材料断裂行为有较大影响，其表现为：在TaC含量较多的外层，材料断裂为脆性断裂，而在TaC含量较少的内层，材料断裂为假塑性断裂。

关键词：C/C复合材料 界面 梯度分布 微观结构 力学性能

Abstract： TaC ceramic interlayer was deposited on carbon fiber in three-dimensional fine-woven punctured felt by using chemical vapor infiltration method. By controlling the flow direction of the reaction gases in the preform， C/C composites with gradient distributed TaC interlayer were obtained. Microstructure， flexural property and fracture toughness of the as-prepared composites were studied. The results show that TaC interlayer is deposited on the surface of carbon fiber and presents a gradient distribution in C/C composites. The average flexural strength and fracture toughness of the as-prepared composites are 272.6 MPa and 5.0 MPa·m1/2， respectively. In general， with the decreasing of the TaC content along the thickness direction （Z-axis） of the composites，the length of carbon fiber pulled out from the carbon matrix becomes shorter. In TaC-rich area， TaC content has significant influence on fracture behavior of the composites. The fracture behavior of the TaC-rich area is brittle in outer layer which has more TaC， while change to pseudo-ductile in inner layer which has less TaC.

Key Words： C/C composite； Interlayer； Gradient distribution； Microstructure； Mechanical property

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