TY - CONF A1 - Altenberger, Igor A1 - Nalla, R. K. A1 - Noster, Ulf A1 - Scholtes, Berthold A1 - Ritchie, Robert O. T1 - On the fatigue behavior and associated effect of residual stresses in deep rolled and laser shock peened Ti-6Al-4V at ambient and elevated temperatures T2 - 2003 TMS annual meeting N2 - Mechanical surface treatments, such as deep rolling, shot peening and laser shock peening, can significantly improve the fatigue behavior of highly stressed metallic components. Deep rolling is an especially attractive technique since it is possible to generate deep, near-surface compressive residual stresses and work hardening while retaining a relatively smooth surface finish. Indeed, this technique is best known for increasing the fatigue strength and lifetime of steel components such as crankshafts. Although most work on deep rolling has been on steels, recently it has also been applied with reasonable success to titanium alloys. Accordingly, in this investigation, we examine the effect of deep rolling on the high-cycle fatigue behavior of Ti-6Al-4V, with particular emphasis on the thermal and mechanical stability of the residual stress states and near-surface microstructures. Preliminary results on laser shock peened Ti-6Al-4V are also presented for comparison. In addition, we examine whether these surface treatments are effective in retaining fatigue strength at the higher temperatures of 300 to 450C. Based on the cyclic deformation and stress/life behavior, together with the X-ray and microstructural observations, it is found that deep rolling can be quite effective in retarding the initiation and initial propagation of fatigue cracks in Ti-6Al-4V at such higher temperatures, despite the almost complete relaxation of the residual stresses at the surface. This clearly implies that, in addition to residual stresses, near-surface microstructures, which in Ti-6Al-4V consist of ultrafine near-surface nanostructures, play a critical role in the enhancement of fatigue lifetimes by mechanical surface treatments. Y1 - 2003 UR - https://opus4.kobv.de/opus4-oth-regensburg/frontdoor/index/index/docId/6171 UR - https://www.researchgate.net/publication/273462702_On_the_fatigue_behavior_and_associated_effect_of_residual_stresses_in_deep_rolled_and_laser_shock_peened_Ti-6Al-4V_at_ambient_and_elevated_temperatures SP - 359 PB - The Minerals, Metals & Materials Society (TMS) ER -