2D-SiCf/SiC复合材料抗拉强度统计分布规律

Statistical distribution of tensile strength of a 2D-SiCf/SiC composite

  • 摘要: 2D-SiCf/SiC复合材料是航空航天领域热端构件的关键材料。材料抗拉强度的统计分布规律在构件的设计与分析中发挥着重要作用。本文测试了化学气相渗透方法制备的2D-SiCf/SiC的室温和1 200℃的抗拉强度,并使用扫描电子显微镜进行了断口形貌分析。采用Weibull分布、正态分布和对数正态分布等三种模型分析了测试结果,并根据Anderson-Darling检验方法进行了检验。结果表明,Weibull分布对2D-SiCf/SiC抗拉强度拟合优于正态分布和对数正态分布。根据Weibull模数大小,1 200℃抗拉强度的分散性大于室温抗拉强度的分散性。利用二参数Weibull分布精确预测了2D-SiCf/SiC室温和1 200℃抗拉强度。分析表明2D-SiCf/SiC抗拉强度的分散性主要来源于纤维/基体界面结合强度和纤维强度的分散性。

     

    Abstract: 2D-SiCf/SiC composite is an important thermostructural material in aeronautics and astronautics fields. The statistical distributions of the tensile strength play a critical role in design, manufacture, examination and verification of the 2D-SiCf/SiC composite and the related components made of the composite. Therefore, the tensile strength of the 2D-SiCf/SiC was measured at room temperature (RT) and 1 200℃. SEM was employed to observe the fracture morphology. The result of the tensile strength was analyzed by Weibull, normal and lognormal distribution statistics and verified by Anderson-Darling method. The result shows the tensile strength at RT and 1 200℃ of 2D-SiCf/SiC can be better described by Weibull distribution than normal distribution and lognormal distribution. The tensile strength at 1 200℃ scatters is at larger range than that at RT according to Weibull model. The average tensile strength can be accurately predicted by the Weibull distribution. The fracture morphology confirms that distribution of the tensile strength of the 2D-SiCf/SiC is mainly caused by the fiber/matrix interfacial bonding strength and the fiber strength.

     

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