从典型失效案例探讨单晶叶片的工程失效问题

Engineering Failure of Single Crystal Blades Based on Failure Cases

通过对目前单晶叶片工程应用中出现的由应力集中以及缺陷引起的两类典型失效问题进行讨论,提出了目前单晶叶片工程应用研究上解决这两类失效问题的途径。分析认为:单晶叶片室温振动疲劳失效对应力集中敏感,因此在结构设计要充分考虑应力集中对振动疲劳失效的影响,优化单晶叶片室温振动疲劳方法,或建立合理可靠的高温振动疲劳试验方法;再结晶和小角度晶界缺陷对单晶叶片的失效有着重要的影响,同时又制约着叶片的合格率,要从工程应用的角度,通过优化工艺和制定合理的缺陷检测或控制标准,使得单晶叶片得到最优的工程应用。

Two main failure modes of single crystal blades caused by stress concentration and metallurgical defects were discussed, and then the solution to these failures were put forward. It is assumed that the room-temperature fatigue failure of single crystal blades is sensitive to stress concentration, so the effect of stress concentration on vibration fatigue failure of single crystal blades should be emphasized in design; room-temperature vibration fatigue testing methods should be optimized and proper high-temperature vibration testing methods should be established for single crystal blades. Recrystallization and small angle grain boundaries have a significant influence on the failure and pass percentage of single crystal blades. Optimal process and reasonable acceptance standards should be applied in engineering application.