Finite element analysis of fretting fatigue properties of GH4169 superalloy considering the surface treatments

•The crack initiated vertical to the surface in the untreated specimen, while parallel in the treated specimen.•The debris would bring the crack away due to the parallel direction, which was one of the mechanisms of life enhancement.•The necessity of considering compression load effect on the crack propagation stage with the linear superposition model was confirmed for GH4169. In the present work, the fretting fatigue properties of GH4169 superalloy at 650℃ were investigated through numerical simulation considering the influences of the surface treatments. As a detrimental phenomenon, fretting fatigue involves fatigue and wear simultaneously, where the coefficient of friction and residual stress fields induced by the surface coating or modification techniques may affect the fretting fatigue lifetimes by changing the complex stress state between the two contacting surfaces. The numerical solutions were implemented to compare the crack initiation angles and paths under different surface conditions. The simulation results indicated that fretting fatigue cracks in residual stress fields were tendentiously parallel to the surface resulting in crack retardation and debris peeling, as verified by experimental observations. Additionally, three propagation models were compared to study the effect of compressive loading on the driving force of crack propagation rates, especially where compressive residual stresses was present. The combination of the linear superposition model with the Harter-T method was proven to be more accurate in the fretting fatigue life prediction, which may provide a modeling basis for service life prediction of engineering components in many practical applications.