DEVELOPMENT STUDY ON TURBINE DISK MADE OF C/C COMPOSITE SUBJECTED TO HIGH TEMPERATURE ENVIRONMENT

对三维纤维增强碳-碳复合材料（3D-C/Cs）应用于ATREX（带膨胀循环的空气涡轮冲压发动机）涡轮盘进行了可行性研究。采用3D-C/C光盘进行了室温下的自旋爆裂试验，并对断裂行为进行了表征。3D-C/C盘在516 m/s （r = 150 mm）的外围速度下完全破裂，这足以满足ATREX的应用。然而，椎间盘周围的纤维束过早地发生了微尺度损伤，纤维束单元的碎片在完全骨折发生之前飞出。为了防止飞出行为，只在圆盘的外围浸渍了Si。尽管这种处理方法提高了飞出行为的启动速度，但对于ATREX的应用来说，这种改进被认为是不够的。其次，对飞出行为进行了简化分析。在此基础上，讨论了以下三种措施：(1)减小纤维束厚度（即使用细纤维纹理）；(2)增加纤维束界面韧性；(3)减小纤维束周向波纹度局部曲率。第三种对策是最有效的，并验证了磁盘局部曲率最小，满足ATREX要求。除上述研究外，还进行了3D-C/Cs耐久性试验。这类研究包括高温行为、蠕变、疲劳和缺口不敏感。3D-C/ c被发现具有足够的以上耐久性为ATREX应用。

A feasibility study of three-dimensionally fiber-reinforced carbon-carbon composites (3D-C/Cs) for application to a turbine disk of ATREX (Air-turbo-ramjet engine with expander cycle) was carried out. Spin burst tests at room temperature were conducted using 3D-C/C disks, and the fracture behaviors were characterized. A 3D-C/C disk was totally fractured at a peripheral speed of 516 m/s (r = 150 mm), which is sufficient for the ATREX application. However fiber-bundles at the disk periphery prematurely suffered micro-scale damage, and fragments of the fiber bundle unit flew out before total fracture occurred. In order to prevent the fly-out behavior, the disk was impregnated with Si only near its periphery. Although This treatment increased the initiation speed of the fly-out behavior, this improvement was considered insufficient for purposes of the ATREX application. Next, a simplified analysis was conducted to characterize the fly-out behavior. Based on this analysis, the following three measures were discussed: (1)decreasing bundle thickness, (i.e.,using fine fiber texture),(2)increasing toughness of the fiber bundle interface, and (3)minimizing local curvature in waviness of the fiber bundles in the circumferential direction. The third countermeasure was found to be most effective and disks minimizing local curvature were verified to satisfy ATREX requirement.In addition to above study, experiments to confirm durability of 3D-C/Cs were carried out. This category of study included, high temperature behavior, creep, fatigue, and notch insensitivity. The 3D-C/Cs were found to possess sufficient above durability for the ATREX application.