Rotating Bending High Cycle Fatigue Property of Handheld Laser Peened A7075BE-T6511 Alloy

Laser peening (LP) processing is one of surface technologies in which a metal material placed in water is irradiated with a pulse laser and peened by the generated shock wave. Since conventional laser peening requires large-scale and high-cost laser equipment, smaller and cheaper pulse laser oscillators have been desired for further industrial applications. In recent years, some handheld pulse laser oscillators have been developed by the ImPACT Program in Japan. In this study, in order to investigate the effectiveness of the new handheld laser device for LP treatment, rotating bending high cycle fatigue tests were conducted on A7075BE-T6511 aluminum alloy. As a result, the high cycle fatigue properties were significantly improved by LP treatment. The fatigue strength at 10⁷ cycles is improved by about 1.5 times, and the fatigue life is extended by about 100 times than those of base metal specimens. In this study, the improvement of fatigue properties by laser peening treatment with a handheld laser oscillator was investigated from the viewpoint of peening effect and fracture mechanism.