Influence of surface orientation on fatigue performance of as-built additively manufactured Inconel 718

The fatigue performance of materials, such as Inconel 718, when produced by Laser Powder Bed fusion, needs to be fully understood to manage and exploit the full potential of this Additive Manufacturing technology. Microstructure and as-built surface morphology are strictly related to process parameters and are known to affect the fatigue response. The present contribution examines experimentally the fatigue behavior of laser powder bed fused Inconel 718 testing specimens printed along three different orientations with respect to the built direction. The observed directional fatigue behavior is discussed in terms of surface quality, near-surface microstructure and their interaction with the fatigue crack initiation mechanisms.