研究了2.5D碳纤维增强SiCN陶瓷基复合材料(ClSiCN)的真空高温拉伸蠕变性能。分别以未热处理及I900℃真空热处理C/SiCN复合材料为研究对象,借助扫描电子显微镜、高精度光电天平及电阻仪研究了蠕变过程中C/SiCN的组织结构、质量及电阻的变化。结果表明:真空拉伸蠕变造成C/SiCN内的裂纹扩展,界面脱粘,纤维滑动、拉直及断裂等蠕变损伤;非晶SiCN基体的晶化造成C/SiCN的质量损失,蠕变过程进一步促进了SiCN晶化,加剧质量损失;CISiCN的电阻在最初阶段下降,随时间增加逐渐升高,其变化受显微组织结构变化影响。真空预热处理的CISiCN在蠕变过程中的显微结构、质量、电阻变化更小,体现了良好的稳定效果。
The vacuum tensile creep properties of 2.5 D carbon fiber-reinforced SiCN matrix composite (C/SiCN) were investgated. The influence of tensile creep on the microstructure, mass and electric resistance of the C/SiCNs un-armealed and annealed at 1 900 ℃ were analyzed via scanning electron microscopy and mass/electric resistance examination. The results indicate that the tensile creep causes some damages like matrix cracks propagation, interface debonding, fiber stretching and sliding. The mass losses are attributed to the amorphous SiCN, which is promoted by the tensile creep process. The electric resistance of C/SiCN firstly decreases and then increases. The variation of electric resistance is consistent with the microstructure change caused by creep damage. The- C/SiCN annealed at 1 900 ℃ has an excellent stabilization effect, exhibiting the smaller structure, mass and electric resistance changes rather than the C/SiCN un-annealed.