Fatigue Performance of Laser Peened Materials

Laser peening is an emerging technology for the surface treatment of metallic materials that is capable of enhancing resistance to fatigue failure. This paper describes some recent results from joint research programs conducted to generate data on residual stress and fatigue performance of laser peened materials. Specifically, we present data for residual stress imparted by laser peening and fatigue life improvement of laser peened coupons relative to as-machined coupons. These data are presented for a range of high-strength materials employed in aircraft and other demanding applications: BSTOA Ti-6A14V titanium alloy, 300M steel, MP35N Ni-Co-Cr-Mo alloy, and 7050-T7451 aluminum alloy. For each material, residual stress distributions were measured for treatment with different laser peening parameter sets. For particular laser peening parameter sets, stress versus life data were generated for as-machined and laser peened fatigue coupons, which quantifies fatigue life improvement attained by laser peening over a range of applied loads.