三维C/C复合材料的压缩性能及破坏机制

Compressive properties and failure mechanism of 3D C/C composites

  • 摘要: 采用扫描电镜、激光共聚焦显微镜观察和力学性能测定的方法,研究了三维C/C复合材料微观结构形貌,以及材料x向、y向和z 向的压缩性能。结果表明,材料内部缺陷明显,纤维束/基体界面结合较弱,材料z向压缩强度和破坏应变均大于x向和y向,压缩应力-应变曲线开始阶段近似线性,随着载荷的增加,曲线表现出明显的非线性特征。从宏观上考察了材料的压缩破坏机制,材料x向、y向和z向破坏模式均为剪切型破坏,纤维/基体界面结合强度对破坏模式影响明显。

     

    Abstract: By means of scanning electronic microscope (SEM),laser scanning confocal microscope (LSCM) and mechanical properties measuring,the microstructure morphology and the compressive mechanical properties of the 3D C/C composite along x,y and z directions were studied. The results show that there are obvious defects,and there is weak adhesion in the fiber/matrix interface of the 3D C/C composite. The compressive strength and fracture strain along z direction are all much greater than those along x direction and y direction. The compressive fracture mechanism of 3D C/C composite was also investigated based on the macro-pictures of the fracture surface of specimens. The results show that the compressive stress-strain curves exhibit the almost linear characteristics at the beginning,and show nonlinear characteristics with the time. Failure models of the samples under compressive load along x,y and z directions present shear fracture. The fiber/matrix interfacial strength has a great effect on the compressive failure mechanism.

     

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