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研究了疲劳氧化环境中3D SiCf/SiC复合材料损伤演变,并对该环境中SiCf/SiC复合材料的失效机制进行了分析。结果表明,疲劳氧化环境中3D SiCf/SiC复合材料的损伤主要为:基体开裂;热解碳界面相脱粘、氧化及取向性排列;纤维断裂、氧化及其结构的改变。这些损伤使氧化性气体通过基体开裂形成的裂纹不断氧化复合材料内部;界面相脱粘和取向性排列使纤维更容易拔出;纤维的氧化、纤维中无定形碳的增多以及SiC晶粒的长大导致纤维强度降低。
The damage evolution of 3D SiCf / SiC composites under fatigue oxidation was studied, and the failure mechanism of SiCf / SiC composites in this environment was analyzed. The results show that the damage of 3D SiCf / SiC composites under fatigue oxidation is mainly caused by matrix cracking, debonding, oxidation and orientation of the pyrolytic carbon interface, fiber fracture, oxidation and structural changes. These damages cause the oxidation gas to crack through the matrix and continuously oxidize the interior of the composite; the interfacial phase debonding and orientation are arranged to make the fiber easier to pull out; the oxidation of the fiber, the increase of the amorphous carbon in the fiber and the growth of SiC grains Large lead to fiber strength reduction.