Improving fatigue performance of thin-walled components via synchronous double-sided ultrasonic surface rolling process

To enhance the vibration fatigue resistance of thin-walled components, surface strengthening techniques have gained significant attention in the aerospace industry. This study introduces the synchronous double-sided ultrasonic surface rolling process (SDUSRP) as a promising method for improving the fatigue resistance of thin-walled components. Experiments were conducted on specially designed specimens simulating the structure of aero-engine blade edges. Two different SDUSRP parameters, primarily differing in the ultrasonic amplitude, were applied to create distinct surface strengthening effects on the specimens. Compared to untreated specimens, those treated with SDUSRP exhibited a fatigue life extension of approximately 10–100 times in different fatigue loads. The substantial improvement in fatigue performance is attributed to the stable fine-grain layer, high amplitude compressive residual stress and their cyclic stability. Additionally, higher ultrasonic amplitude enhances grain refinement through dislocation proliferation and the formation of dislocation slip bands, leading to the fragmentation and separation of grains. The SDUSRP technique demonstrated in this study shows great potential for tailoring and adjusting residual stress and microstructure in thin-walled structures, offering a valuable complement to existing anti-fatigue manufacturing methods for such components.