Nanoindentation tests were conducted to investigate the near-surface mechanical properties of the individual components(fiber and matrix) for three-dimensional reinforced carbon/carbon composites(3D C/C).Optical micro...Nanoindentation tests were conducted to investigate the near-surface mechanical properties of the individual components(fiber and matrix) for three-dimensional reinforced carbon/carbon composites(3D C/C).Optical microscope and polarizing light microscope were used to characterize the microstructure of 3D C/C.The microscopy results show that large number of pores and cracks exist at both bundle/matrix interface and pitch carbon matrix.These defects have important effect on the mechanical behavior of 3D C/C.The in situ properties for components of 3D C/C were acquired by nanoindentation technique.Relative to the matrix sample,the fiber samples have more larger values for modulus,stiffness and hardness.However,there is no significant difference of modulus and stiffness among fiber samples with different directions.展开更多
文摘为研究二维编织陶瓷基复合材料不同沉头深度和沉头角度的单钉沉头螺栓连接结构的挤压力学性能,在相同的拧紧力矩下,对单钉沉头螺栓连接结构进行了拉伸试验,获得了不同沉头深度和角度下连接结构的拉伸载荷-位移曲线。参考ASTM D5961标准中的数据处理方法,分析得到了挤压强度和最大载荷,以及挤压强度与沉头角度和沉头深度的关系。用DIC(3D Digital Image Correlation)系统观测了复合材料板连接孔附近的全场应变分布,分析了挤压试验件连续的应变累积过程和典型破坏模式的DIC应变云图,使用三维显微镜观测了试件的局部破坏模式。研究可以为陶瓷基复合材料沉头螺栓连接结构的设计提供参考。
基金Project(61391) supported by the National Security Basic Research Program of ChinaProject (91016029) supported by the National Natural Science Foundation of China
文摘Nanoindentation tests were conducted to investigate the near-surface mechanical properties of the individual components(fiber and matrix) for three-dimensional reinforced carbon/carbon composites(3D C/C).Optical microscope and polarizing light microscope were used to characterize the microstructure of 3D C/C.The microscopy results show that large number of pores and cracks exist at both bundle/matrix interface and pitch carbon matrix.These defects have important effect on the mechanical behavior of 3D C/C.The in situ properties for components of 3D C/C were acquired by nanoindentation technique.Relative to the matrix sample,the fiber samples have more larger values for modulus,stiffness and hardness.However,there is no significant difference of modulus and stiffness among fiber samples with different directions.
