采用高温真空蠕变试验机研究了1300℃和1500℃下三维(3D)C/SiC复合材料的蠕变行为,分析了温度对该复合材料蠕变速率的影响,并通过扫描电镜和透射电镜分析了蠕变前后复合材料的显微结构。结果表明:不同温度下该复合材料的高温蠕变曲线均由减速蠕变阶段和稳态蠕变阶段两部分组成,试样断裂前没有出现加速蠕变阶段;温度越高,靠近SiC基体处的热解碳界面相由乱层石墨组织转变为高度取向排列的石墨片层组织的厚度就越大,从而导致复合材料界面滑移阻力更低,蠕变速率更快。
The creep behavior of three-dimensional (3D) C/SiC composites was examined at 1 300 ℃ and 1 500 ℃ using vacuum high-temperature creep testing machine_ The effect of temperature oft the creep rate of the composites was also investigated. Microstructure of the composites before and after creep testing was analyzed by means of SEM and TEM. The results indicate that the creep curves of 3D C/SiC composites were composed of two stages including deceleration creep stage and steady state creep stage, and no accelerated creep stage was observed until the fracture of the specimens. With the increase of temperature, the interracial sliding resistance decreased due to the increase of the thickness of highly oriented lamellar graphite transformed from turbostratic graphite in the pyrolytic carbon interphase near the SiC matrix, resulting in a more rapid creep rate of 3D C/SiC composites.