Assessment of mechanical properties and fatigue performance of a selective laser melted nickel-base superalloy Inconel 718

In the present work a nickel-base superalloy Inconel 718 manufactured by selective laser melting (SLM) was investigated with focus on microstructure, orientation-dependent mechanical property and fatigue performance. Comparative material testing and characterization of the SLM and the forged Inconel 718 revealed significant differences in both microstructures and mechanical properties. The columnar grain structure of SLM alloy leads to the orientation-dependent mechanical properties, which matches the Hall-Petch relation. The inhomogeneous microstructures and slit shaped lack-of-fusion (LoF) defects from the SLM process result in worse fatigue performance and deteriorate the fatigue crack growth behavior.