钛合金保载疲劳失效特征及敏感性判定方法

Characteristics of Dwell Fatigue Failures and Method for Assessing the Dwell Sensitivity of Titanium Alloys

钛合金在航空发动机上使用时存在保载疲劳失效现象。钛合金保载疲劳寿命显著低于普通疲劳寿命且其断裂特征有别于普通疲劳。本文通过系统的实验研究,从疲劳断口、二次裂纹以及应变积累等方面总结了保载疲劳的失效特征。研究对象涵盖了保载敏感性强、弱以及无的钛合金类型。利用上述总结的特征,给出了判定钛合金保载疲劳失效及敏感性强弱的方法。

Titanium alloys have come up against dwell fatigue failures during service in the aircraft engine.In contrast to normal continuous cycling,dwell fatigue is manifested by a significant reduction in fatigue life and has distinct failure characteristics.Through the systematic experimental research,where research objects covered from highly susceptible to unsusceptible titanium alloys,the characteristics of dwell fatigue failures have been summarized from three aspects,including the fatigue fracture,secondary crack and strain accumulation.According to the summarized failure characteristics,the method for identifying the dwell fatigue failure and assessing the dwell sensitivity has been put forward.