Fatigue Performance of Laser Peened 7050-T7451 Aluminum Alloy

Laser peening is an emerging technology for the surface treatment of metallic materials that is capable of enhancing resistance to fatigue failure. This paper presents results quantifying the effects of laser peening on residual stress and fatigue performance of samples machined from 7050-T7451 aluminum alloy. Residual stress distributions were measured for treatment with different laser peening parameter sets using the slitting method. For particular laser peening parameter sets, stress versus life data were generated over a range of applied loads and compared with as-machined and shot peened results. Two different sample types were used for fatigue testing: smooth bend bars and notched bend bars. In general, laser peening produced a fatigue life improvement of approximately 3 to 6 relative to as machined samples and 1.5 to 2 relative to shot peened samples over the range of stress levels tested.