CVI-iC/TaC改性C/C复合材料的力学性能及其断裂行为
详细信息Mechanical properties and fracture behavior of CVI-iC/TaC modified C/C composite
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摘要: 以针刺碳纤维整体毡为预制体，采用化学气相渗透工艺对预制体纤维进行PyC/SiC/TaC的多层复合模式的涂层改性， 然后采用化学气相渗透和热固性树脂浸渍-化进行增密，制备出新型C/C复合材料。对复合材料的微观结构和力学性能进行了研究。结果表明：包覆在碳纤维表面的PyC/SiC/TaC多层结构均匀致密、无裂纹，在C/C复合材料中形成空间管状网络结构；改性后C/C复合材料的抗弯强度和韧性均大大提高， 平均抗弯强度达到522 MPa，断裂位移达到1.19mm；复合材料弯曲断裂形式表现为脆性断裂，经过2000℃高温热处理以后，复合材料的抗弯强度下降，但最大断裂位移增大，弯曲断裂形式由脆性断裂转变为良好的假塑性断裂。Abstract: Using needled carbon fiber felt as the preform，the fiber coating with multilayered (PyC/SiC/TaC) fabricating by chemical vapor infiltration was used to modify C/C composites. The novel C/C composites were fabricated by chemical vapor infiltration and impregnation of thermosetting resin and carbonization. The microstructures and mechanical properties of C/C composites were investigated. The results show that the multilayered (PyC/SiC/TaC) coating enwraps around the carbon fiber evenly and compactly and forms cannular microstructure in C/C composites; both the strength and toughness of modified composites increase apparently. The average flexural strength of the composites reaches 522MPa，the maximum fracture displacement reaches 1.19mm，and the fracture mode shows brittle fracture. After high temperature treating (HTT) at 2000℃，the flexural strength of the composites decreases，while the maximum fracture displacement increases，and the fracture mode of the composites shows "pseudo plastic" fracture.
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Keywords:
- C/C composites /
- modification /
- microstructure /
- fracture behavior /
- HTT
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