【摘要】 分别采用热膨胀仪和激光脉冲热导仪测量了2维、2.5维和3维纤维编织结构的碳纤维增强碳化硅(carbon fiber reinforced silicon carbide,C/SiC)复合材料从室温到1400℃温度范围内纵向和横向热膨胀系数,以及厚度方向的热扩散系数。用扫描电镜、光学显微镜观察了样品的微结构。结果表明:低温段(700℃以下),3种C/SiC的纵向和横向热膨胀系数均随温度的升高而缓慢增大,并在700℃之后出现不同程度的波动;高温段(700℃以上),它们的纵向热膨胀系数和2维C/SiC的横向热膨胀系数随温度的升高而减小,而2.5维和3维C/SiC的横向热膨胀系数则随着温度的升高而迅速增大。三者厚度方向的热扩散系数均随温度的升高而减小,3维C/SiC的热扩散系数最大,分别是2.5维C/SiC和2维C/SiC的1～1.2和1.4～2倍。更多还原

【Abstract】 The thermal expansion coefficient and the thermal diffusivity of 2 dimensional (D), 2.5D and 3D carbon fiber reinforced silicon carbide (C/SiC) composites were tested from room temperature to 1400 ℃ using a thermal dilatometer and laser flash appara-tus. The microstructure was observed by scanning electron microscopy and light microscopy. The results show that at low temperature (below 700℃), the longitudinal and transversal thermal expansion coefficients of all these C/SiC composites increase slowly as the temperature increases, followed by fluctuations of different degrees after 700 ℃ . At high temperature above 700 ℃, the longitudinal thermal expansion coefficients of all these materials and the transversal coefficient of the 2D C/SiC composite decrease as the temperature increases, but the transversal thermal expansion coefficients of the 2.5D and 3D C/SiC composites increase sharply as the temperature increases. The thermal diffusivity of all these composites decreases as the temperature increases, and the thermal diffusivity of the 3D C/SiC composite is the highest, it is 1-1.2 and 1.4-2 times higher than the 2.5D and 2D C/SiC composites respectively.更多还原