中文摘要：

基于航空发动机涡轮盘榫槽结构特点及其工作状态，采用榫槽模拟件对GH4720合金的疲劳失效机理和裂纹扩展寿命进行了实验研究和理论分析。研究结果表明：GH4720合金榫槽模拟件的疲劳失效表现为3个阶段：（i1模拟涡轮盘榫槽处由于较高的应力集中而产生滑移，进而萌生裂纹；（ii）随着应力集中和循环载荷的持续，相邻晶粒间位错开动、发生滑移，裂纹在晶粒间传递；（iii）随着应力强度因子范围增大，剪应力和主应力交互作用、滑移系开动及位错在不同滑移系间的运动，裂纹快速扩展。在实验基础上建立了GH4720合金的疲劳裂纹扩展寿命模型，基于有限元分析的榫槽处的应力和裂纹扩展寿命模型得到的裂纹扩展寿命与实验结果相符，表明该裂纹扩展寿命模型可用于工程中预测涡轮盘的剩余寿命。

英文摘要：

Based on the structural features and the work status of the aero-engine turbine disk groove, the experimental and theoretical analysis of the fatigue failure mechanism and the crack growth life of the groove modeling specimen of GH4720 alloy were carried out. The fatigue failure of the groove modeling specimen of GH4720 alloy can be divided into three stages： （i） due to the high stress concentration, slip systems are activated and then cracks initiate; （ii） with the increase of loading cycles, adjacent intergranular dislocations and slip systems are activated, cracks transfer between grains; （iii） with the increase of the stress intensity factor range and the cooperation of shear stress and principal stress, the dislocations motion in different slip systems and the crack propagation are accelerated. A fatigue crack growth life model of GH4720 alloy has been established. The crack growth lives obtained from the finite element analysis and the life model have a good agreement with the results of the experiment. It is demonstrated that the life model can be used in engineering to predict the remaining life of turbine disk.