ABSTRACT

The corrosion behavior and microstructure evolution of SiC_f$/\mathrm{P}\mathrm{y}\mathrm{C}/\mathrm{S}\mathrm{i}\mathrm{C}{}_m$ composites in a binary oxidizing gas environment containing water vapor and oxygen are simulated. The mechanical model and life prediction of composite materials in a water-oxygen coupled environment strongly depend on a thorough understanding of crack opening and healing, interface degradation, and fiber oxidative embrittlement. The evolution of the distribution of oxidant concentration, oxide layer thickness, and interface degradation degree over time was evaluated, and the effects of temperature and interface layer thickness were discussed. In addition, the simulation results in a binary oxidizing gas environment are compared with those in a single oxidizing gas environment. Although the binary oxidizing gas environment is more violent to the fiber, it is conducive to the rapid healing of small-sized matrix cracks. The dependence of the interface degradation length on temperature and interface layer thickness is similar to that in a single oxidizing gas environment.

摘要

SiC _f的腐蚀行为和微观结构演变$/\mathrm{磷}\mathrm{是}\mathrm{C}/\mathrm{秒}\mathrm{一世}\mathrm{C}{}_{米}$在含有水蒸气和氧气的二元氧化气体环境中模拟复合材料。复合材料在水氧耦合环境中的力学模型和寿命预测很大程度上取决于对裂纹打开和愈合、界面退化和纤维氧化脆化的透彻理解。评估了氧化剂浓度分布、氧化层厚度和界面退化程度随时间的演变，并讨论了温度和界面层厚度的影响。此外，将二元氧化气体环境中的模拟结果与单一氧化气体环境中的模拟结果进行了比较。虽然二元氧化气体环境对纤维更剧烈，但有利于小尺寸基体裂纹的快速愈合。