某型航空发动机在外场服役过程中出现声音异常现象, 地面检查发现高压1, 2级涡轮叶片以及高压2级涡轮导向叶片全部折断。通过现场勘查、断口分析以及金相检查等手段, 确认了由伸根梨形孔处断裂的高压1级涡轮叶片是该次失效的首断件, 聚集分布的铸造疏松缺陷是引起其早期疲劳断裂的主要原因; 其他各级涡轮叶片断裂均属二次损伤引起的过载断裂。

Some unusual sounds appeared when an aero-engine was servicing. When it was checked on the ground it was found that all the HP1, HP2 turbine blades and HP2 guide vanes fractured. By means of on-site investigation, fracture analysis and metallographic examination, it was found that the HP1 turbine blade which fractured at the root elongation was the first fracture part, and the gathered distribution of casting loose defect was the main cause for the early fatigue fracture of the HP1 turbine blade. Fracture of all the other turbine blades was overload fracture caused by secondary injury.