C/C復合材料高溫長時燒蝕行為與控制方法

熊翔

摘 要：利用化學氣相滲透法在三維細編穿刺炭氈中的炭纖維表面沉積TaC陶瓷界面，通過控制氣體在預制體中的流動方向，獲得梯度分布TaC界面改性C/C復合材料。研究了材料的微觀結構、彎曲性能以及斷裂韌性，結果表明：TaC呈層狀分布在炭纖維表面，從C/C復合材料表層到內部，TaC陶瓷相的含量呈梯度分布；梯度分布TaC界面改性C/C復合材料的平均彎曲強度為272.6 MPa，平均斷裂韌性為5.0 MPa·m1/2；整體上，沿材料厚度（Z軸）方向，隨TaC含量的降低，纖維的拔出長度明顯變短；在表層富TaC區，TaC含量對材料斷裂行為有較大影響，其表現為：在TaC含量較多的外層，材料斷裂為脆性斷裂，而在TaC含量較少的內層，材料斷裂為假塑性斷裂。

關鍵詞：C/C復合材料 界面 梯度分布 微觀結構 力學性能

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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