【摘要】 在不同应力比条件下对2.5D C/C复合材料试样进行了弯-弯疲劳循环加载试验,用三点弯曲法测定了2.5D C/C复合材料试样在疲劳试验前后的弯曲强度,利用扫描电镜观察了其断口形貌,并分析了2.5D C/C复合材料的疲劳强化机理。结果表明:2.5D C/C复合材料的热解炭结构是内层的光滑层与外层的各向同性层组织结构。疲劳循环加载后,不同应力比条件下2.5D C/C复合材料的剩余弯曲强度均得到提高,且应力比为0.2时,剩余弯曲强度最大,约为174.0 MPa,较静态弯曲强度提高了93.8%。更多还原

【Abstract】 The fatigue behavior of 2.5D C/C composite samples under different stress ratios was investigated in flexural mode. Static flexural strength before fatigued testing and residual flexural strength of the samples after fatigued testing were tested. The microstructure of the pyrolytic carbon and fracture morphology of the samples were studied by polarized light microscope and scanning electron microscope, respectively. The results show that the pyrolytic carbon of the samples consists of smooth laminar and isotropic structure. The residual flexural strength of 2.5D C/C composites is improved under different stress ratios and fatigue cyclic loading testing increase. And when the stress ratio is 0.2, the residual flexural strength of 2.5D C/C composites reached the maximum value of 174.0 MPa, which is higher 93.8% than the static flexural strength.更多还原