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为研究陶瓷基复合材料的低周疲劳失效机理,通过试验和细观分析对其疲劳特性进行了探讨。研究了室温下加载循环数对2D针刺C/SiC复合材料拉-拉疲劳剩余强度的影响,并采用光学显微镜和扫描电子显微镜对该材料的断口形貌和微观结构进行了观察。结果表明:2D针刺C/SiC复合材料具有较好的抗疲劳特性,在85%极限拉伸强度(UTS)载荷下的循环数超过10~6;随着加载循环数的增加,剩余强度先增大然后下降。断口分析表明:纤维拔出长度随着加载循环数的增加而增加,说明在疲劳加载过程中,纤维/基体的界面结合强度降低,减缓了材料内部受力的不均匀性,提高了材料的承载能力,使2D针刺C/SiC复合材料出现了疲劳强化现象。
In order to study the mechanism of low cycle fatigue failure of ceramic matrix composites, the fatigue characteristics of the composites were investigated by means of experiments and meso-analyzes. The effects of loading cycles at room temperature on the pull-pull fatigue residual strength of 2D needle-punched C / SiC composites were investigated. The fracture morphology and microstructure of the composites were observed by optical and scanning electron microscopy. The results show that the 2D needle-punched C / SiC composites have good anti-fatigue properties, and the number of cycles under the 85% ultimate tensile strength (UTS) load exceeds 10-6. With the increase of loading cycles, the residual strength first Increase then decrease. Fracture analysis shows that the fiber pull-out length increases with the increase of loading cycles, which shows that the bonding strength of the fiber / matrix decreases during the fatigue loading process, which reduces the inhomogeneity of the material internal stress and improves the bearing capacity of the material Ability to make 2D acupuncture C / SiC composite fatigue phenomenon.