Investigation of ultrasonic AWJ peening performance on aluminum alloy

Ultrasonic vibration was employed to enhance the processing performance of abrasive waterjet peening. Experiments and simulations were conducted to investigate the effects of ultrasonic vibration on the surface characteristics and fatigue performance of the treated specimens. The results indicated that the microstructure of the surface layer material after ultrasonic AWJ peening was refined. Moreover, the maximum hardness and the thickness of the hardened layer were greater under vibration conditions. The surface compressive residual stress and the maximum compressive residual stress were also increased. The increase in surface roughness indicates that the application of ultrasonic energy enhances the surface plastic deformation of the specimen. Compared with traditionally AWJ-peened specimens, the fatigue life of those treated with ultrasonic AWJ peening increased by up to 37%. This improvement can be attributed to the severe plastic deformation and the enhanced compressive residual stress.