Investigation of Fretting Fatigue Behavior of Shot Peening–Treated Ti‐6Al‐4V Dovetail Joints

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This study investigates the fretting fatigue behavior of shot peening (SP) on Ti‐6Al‐4V dovetail tenons and slots in a room‐temperature environment. A real‐time crack observation system was developed to facilitate this research. The results show that SP can significantly improve the fretting fatigue life of dovetail specimens, especially the crack initiation life. However, SP treatments on the dovetail tenons can lead to fatigue fracture failures in untreated dovetail slots. Notably, the SP treatment applied to both the dovetail tenon and dovetail slot improved the fretting fatigue life by approximately 600% compared to the untreated specimens. This improvement is primarily attributed to the fact that the SP treatment introduced a certain depth of plastic deformation layer, and the presence of compressive residual stresses inhibited the crack initiation and early propagation rates. In addition, the high roughness friction interface changes the early fretting operation mechanism and stress distribution, thus reducing the stress concentration at the lower edge of the contact zone.