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研究了2.5D碳纤维增强SiCN陶瓷基复合材料(C/SiCN)的真空高温拉伸蠕变性能。分别以未热处理及1 900℃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;C/SiCN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C/SiCN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 creep properties of 2.5D carbon fiber reinforced SiCN ceramic matrix composites (C / SiCN) under vacuum at high temperature were studied. The structure, mass and resistance of C / SiCN were investigated by means of scanning electron microscopy (SEM), high-precision photobalance and resistance meter, respectively. The heat-treated C / SiCN composites were annealed at 1100 ℃ for 1 h. The results show that vacuum tensile creep causes creep damage in C / SiCN, such as crack propagation, interface debonding, fiber sliding, straightening and fracture. Crystallization of amorphous SiCN matrix leads to mass loss and creep of C / SiCN The process further promotes the crystallization of SiCN, which aggravates the mass loss. The resistance of C / SiCN decreases at the initial stage and gradually increases with time, and the change is affected by the microstructure and structure changes. The microstructure, mass and resistance change of C / SiCN treated by vacuum preheating are smaller and show a good stabilizing effect.