【摘要】 为揭示重铸层对气膜孔疲劳性能影响的内在机理以及重铸层影响下的疲劳裂纹的萌生及扩展规律，采用工业相机拍摄了裂纹动态扩展过程，并通过图像分析法获取裂纹演变过程的位移图及应变云图，采用数字图像相关方法分析裂纹扩展过程及孔边应变变化过程。分析结果显示，带重铸层小孔试件的疲劳寿命可分为裂纹萌生、裂纹扩展和失稳瞬断三个阶段，其中裂纹萌生阶段约占总寿命的76%，裂纹扩展阶段约占总寿命的24%，而失稳瞬断阶段不足总寿命的0.1%。该结果表明，重铸层主要通过影响裂纹萌生阶段主导疲劳失效过程，为气膜孔加工质量控制及疲劳寿命提升提供了重要理论依据。更多还原

【Abstract】 To elucidate the underlying mechanism of the recast layer on the fatigue performance of film holes and clarify its influence on crack initiation and propagation behavior,an industrial camera was employed to capture the dynamic crack propagation process. Image analysis techniques were applied to derive displacement maps and strain distribution diagrams of the crack evolution. Digital image correlation(DIC) was utilized to examine both the crack propagation and the strain variation around the hole. Observations and image analysis revealed that the fatigue life of specimens with recast layers can be divided into three stages:crack initiation,crack propagation,and unstable instantaneous fracture. The crack initiation stage accounted for approximately 76% of the total lifespan, while the propagation stage constituted approximately 24%. The unstable fracture phase, however,represented less than 0.1% of the total fatigue life. These findings reveal that the recast layer predominantly governs the fatigue failure process by affecting the crack initiation stage,providing important theoretical support for improving machining quality and extending fatigue life of film holes.更多还原