Effect of Ultrasonic Surface Peening on Fatigue Property of 7B04 High Strength and Toughness Aluminum Alloy

Abstract

This paper discusses the influence of ultrasonic surface peening on the fatigue property of 7B04 high strength and toughness aluminum alloy. The results showed that a nano-layer of 10-20 μm was formed after ultrasonic surface peening. This nano-layer had a gradient structure with grain size of 10 to 50nm. Further, the ultrasonic surface peening process created residual compressive stress of 200MPa in this nano-layer. This stress caused micro surface cracks to be compressed or closed . Consequently, after ultrasonic surface peening the fatigue life of 7B04 alloy was extended to 5 times.