In order to study the mechanical properties and failure mechanism of the axial braided C/C composites, the microscopic and macroscopic mechanical properties of the composite were investigated. In view of the size effect of the samples, the properties of the samples with different thickness were tested. The strain during loading was measured by optical method, and the failure morphology was observed by SEM. The changing characteristics of stress-strain curve were analyzed, and the failure characteristics of materials and failure mechanism under various loads were obtained. It was found that brittle fracture was observed during the tensile process of axial braided C/C composites, and the main failure forms were fiber rod pulling and partial fiber rod breaking in the axial direction. Radial failure was mainly in the form of fiber bundle fracture and crack stratification propagation. When compressed, the material exhibited pseudoplastic characteristics. The radial compression sample was cut along a 45-degree bevel. The axial compression curve was in the form of double fold, the axial fiber rod was unstable, and the transverse fiber bundle was cut. During in-plane shearing, the axial fracture was brittle and the fiber rod was cut. The radial direction showed the fracture and pulling of the fiber bundle, and the material had the characteristics of pseudoplasticity. The research methods and results in this paper could provide important references for the optimization and rational application of C/C composite materials.

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轴向编织C / C复合材料的力学性能及失效机理研究

为了研究轴向编织C / C复合材料的力学性能和破坏机理，研究了复合材料的微观和宏观力学性能。考虑到样品的尺寸效应，测试了具有不同厚度的样品的性能。通过光学方法测量加载过程中的应变，并通过SEM观察破坏形态。分析了应力-应变曲线的变化特征，得出了材料在不同载荷下的破坏特性和破坏机理。发现在轴向编织的C / C复合材料的拉伸过程中观察到脆性断裂，主要破坏形式为纤维棒拉动和部分纤维棒在轴向断裂。径向破坏主要表现为纤维束断裂和裂纹分层扩展的形式。当压缩时，该材料表现出假塑性特征。沿45度斜角切割径向压缩样品。轴向压缩曲线为双折形式，轴向纤维棒不稳定，横向纤维束被切断。在面内剪切期间，轴向断裂是脆性的，并且纤维棒被切割。径向显示纤维束的断裂和牵拉，该材料具有假塑性特征。本文的研究方法和结果可为C / C复合材料的优化和合理应用提供重要参考。沿45度斜角切割径向压缩样品。轴向压缩曲线为双折形式，轴向纤维棒不稳定，横向纤维束被切断。在面内剪切期间，轴向断裂是脆性的，并且纤维棒被切割。径向显示纤维束的断裂和牵拉，该材料具有假塑性特征。本文的研究方法和结果可为C / C复合材料的优化和合理应用提供重要参考。沿45度斜角切割径向压缩样品。轴向压缩曲线为双折形式，轴向纤维棒不稳定，横向纤维束被切断。在面内剪切期间，轴向断裂是脆性的，并且纤维棒被切割。径向显示纤维束的断裂和牵拉，该材料具有假塑性特征。本文的研究方法和结果可为C / C复合材料的优化和合理应用提供重要参考。径向显示纤维束的断裂和牵拉，该材料具有假塑性特征。本文的研究方法和结果可为C / C复合材料的优化和合理应用提供重要参考。径向显示纤维束的断裂和牵拉，该材料具有假塑性特征。本文的研究方法和结果可为C / C复合材料的优化和合理应用提供重要参考。