九级整流叶片断裂分析

某型发动机经150h长期试车（总工作时间大约为170h）,之后进行3次喘振试验,分解后发现九级整流叶片断裂。对叶片断口的宏、微观特征进行分析,对断裂叶片的成分、硬度、金相组织进行检查,并进行叶片振动计算和测频分析。结果表明：九级整流叶片断裂是由于其U型槽与叶背交接处有一棱边,叶片最大的受力位置正是该处,加之棱边局部打磨不圆滑,在源区附近存在加工刀痕,在该处形成了应力集中的疲劳源,最终导致叶片发生疲劳断裂。

Failure Analysis of Stage 9 Stator Blade

A stage 9 stator blade in an engine was found to have fractured after testing for 150h and surge testing for three times.In order to find out the mode and cause of the failure,macro and micro observation,chemical composition analysis,hardness testing and metallurgical structure examination were performed.In addition,vibration calculation and frequency measuring were carried out on the blade.The results show that the fracture of the blade is fatigue fracture resulting from stress concentration.There existed an edge at the joint of the U-shape groove and the dorsal side of the blade,where the largest stress existed.In addition,there existed machining traces near the fatigue source.Stress concentration resulted in the fatigue fracture.