C/C刹车材料摩擦表面层的微结构

采用透射电子显微镜（TEM）、 拉曼光谱（RMS）、 扫描电子显微镜（SEM）等手段, 研究了C/C复合材料在刹车过程中摩擦表面层微观结构变化, 建立了微结构模型; 利用有限元分析方法仿真了具有微凸体的试样在摩擦过程中的温度分布。研究表明: 摩擦表面除了形成一层数微米厚的摩擦层外, 还在摩擦层上不均匀地覆盖一层摩擦膜； TEM及选区电子衍射图（SAED）结果显示摩擦膜大部分区域为中等织构, 随着到外表面距离的减小， 织构度逐渐升高, 且在摩擦膜的最表面发现高石墨化度的区域; RMS同样证实摩擦表面存在局部高石墨化度区域, 摩擦过程中粗糙表面微凸体的最高温度远大于摩擦平面, 是导致摩擦表面应力石墨化的主要因素之一。 

Microstructures of the worn surface layer of C/C composites

Microstructural changes of C/C composites after braking test were studied by TEM, RMS, SEM and so on. Microstructural model of worn surface layer was established. Temperature fields of specimens with asperities were simulated by Finite Element Method (FEM). The results show that a friction layer with several microns forms on the matrix firstly, and then a friction film covers on the friction layer unequally. TEM and SAED indicate that most fields of the friction film are middle textured, and the texture degree increases with approach to the worn surface. The outmost surface is highly graphitized, and this result is verified by RMS. The highest temperature of asperities is much higher than that of worn plane, which is one of the main factors of stress graphitization on worn surface.