摘要
为探究氧化作用对2.5D编织C/SiC复合材料疲劳性能的影响,开展C/SiC复合材料在高温空气和惰性气体环境中的疲劳行为研究。采用应力比0.05,频率10 Hz的正弦波分别在1 200℃惰性气体和1 200℃空气环境下对2.5D编织C/SiC复合材料开展疲劳试验。1 200℃惰性气体环境下循环基数为10~6的疲劳极限约为160 MPa,1 200℃空气环境下循环基数为10~4的疲劳极限约为130 MPa。随着循环次数的增加,迟滞回线呈现右移的趋势,循环数相同时,空气环境的位移大于惰性气体环境的位移。通过扫描电子显微镜表征疲劳失效试件断口的形貌,发现纤维表面较为粗糙,呈现出明显的氧化迹象。采用能谱仪分析疲劳氧化特征,发现SiC基体氧化形成SiO2。高温空气环境中,氧气的存在显著降低了材料的疲劳性能,氧化作用加速了疲劳失效。在机械载荷作用下,纤维、基体和界面的性能不断退化,导致界面磨损、界面脱粘和纤维拔出。氧化后纤维的受力状态恶化,失效概率增加,成为复合材料中的薄弱部分,易发生断裂。
In order to explore the effect of oxidation on the fatigue properties of 2.5D woven C/SiC compos⁃ites,the fatigue experiments of C/SiC composites were carried out in air and inert gas environments using a sine wave with a stress ratio of 0.05 and a frequency of 10 Hz at 1200℃.The fatigue limit in inert gas environment with a cyclic basis of 106 is about 160 MPa,and that in air environment with a cyclic basis of 104 is about 130 MPa.The hysteresis loop shows a rightward shift as the number of cycles increases,and the displacement in air environment is larger than that in inert gas environment at the same cycle number.The fracture morphology of fatigue failure specimens was characterized by scanning electron microscope,and it was found that the surface of the fiber was rough and showed obvious signs of oxidation.The fatigue oxidation characteristics were analyzed by energy spectrum instrument,and it was found that the SiC matrix was oxidized to form SiO2.In high temperature air environment,the presence of oxygen significantly reduces the fatigue properties of the material,and oxidation promotes the process of fatigue failure.Under the action of mechanical load,the properties of fiber,matrix and in⁃terface continue to deteriorate,leading to interface wear,interface debonding and fiber pullout.After oxidation,the stress state of the fiber deteriorates,the probability of fiber failure increases,and the fiber becomes the weak part of the composites,which is prone to fracture.
作者
张禄
宦婷
葛海浪
杨雨晨
贾冰岳
刘伟
焦健
高希光
宋迎东
ZHANG Lu;HUAN Ting;GE Hailang;YANG Yuchen;JIA Bingyue;LIU Wei;JIAO Jian;GAO Xiguang;SONG Yingdong(College of Energy and Power,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China;Beijing Power Machinery Institute,Beijing 100074,China;AECC Beijing Institute of Aeronautical Materials,Beijing 100095,China;Harbin Engineering University,Harbin 150001,China)
出处
《推进技术》
北大核心
2025年第9期309-318,共10页
Journal of Propulsion Technology
基金
国家科技重大专项(Y2019-I-0018-0017)。
关键词
陶瓷基复合材料
高温疲劳
疲劳极限
失效机理
氧化损伤
Ceramic matrix composites
High temperature fatigue
Fatigue limit
Failure mechanisms
Oxidative damage
