C/C复合材料在原子氧辐照下的结构性能演变

通过分析失重率、显微形貌变化讨论了原子氧辐照对C/C复合材料以及SiC基体改性C/C复合材料(C/C-SiC)的损伤机制; 并通过热膨胀系数(CTE)、热扩散率(TD)以及弯曲强度等性能的变化, 进一步讨论了原子氧辐照损伤对材料热物理及力学性能影响。结果表明, C/C复合材料受原子氧辐照损伤是物理化学综合作用, 属于冲击诱发-增强表面化学刻蚀; SiC组元表现出良好的抗原子氧侵蚀性能, 阻碍了原子氧向材料内部侵蚀, 但是SiC组元在更长时间辐照后出现机械破损; C/C复合材料在原子氧辐照下失重率呈线性增加, 而C/C-SiC复合材料失重率小于C/C复合材料且增长幅度越来越小; C/C复合材料和C/C-SiC复合材料的整体结构性能在辐照损伤后发生了一定变化。

Degradation Behaviour of C/C composites by Atomic Oxygen Irradiation

Erosion mechanisms of C/C composite and C/C-SiC composite (matrix modification for C/C composite using SiC) irradiated by atomic oxygen (AO) were studied by analyzing erosion morphology and mass loss rate. Thermal diffusivity coefficient, thermal expansion coefficient and flexural strength were determined before and after AO exposure test to discuss thermal physics and mechanics of AO damage. The results show that the erosion of C/C composite is the cooperation of chemical oxidation and mechanical erosion, which can be termed bombardment-induced surface chemical etching. The SiC components show good resistance to atomic oxygen erosion and hinder internal erosion. However, SiC components can also be damaged mechanically as the exposure time increasing. The mass loss rate of C/C composite is approximately proportional to the exposure time, while the mass loss rate of C/C-SiC composite is smaller than that of C/C composites and the increase of the mass loss rate slows down as the exposure time increasing. The changes of thermophysical property and mechanical property show that the overall performances of C/C and C/C-SiC have been changed to some extent after the AO exposure testing.