Surface treatment impact on fatigue life at 550 °C of the as-built Inconel 718 manufactured by laser-powder bed fusion

Abstract

This article compares the impact of surface modification on fatigue life at 550 °C of the Inconel 718 manufactured by laser-powder bed fusion. The surface conditions are as-built, as-machined, shot-peened, oxidized, and combinaisons of those. Surface roughness, microhardness, and residual stress measurements, as well as fractographic analyses are performed to interpret the fatigue results. Fatigue tests show that as-built samples have higher fatigue lifetime than as-machined samples. Moreover, shot peening increases fatigue lifetime. Finally, an oxidation treatment at 550 °C during 41.6 days does not affect fatigue life.