Fatigue behavior of notched and unnotched AM Scalmalloy specimens subjected to different surface treatments

In the present work, the fatigue resistance values of Scalmalloy specimens obtained by selective laser melting (SLM) additive manufacturing (AM) are experimentally studied. The fatigue levels of specimens with and without notches after applying different surface treatments, such as sand blasting, shot peening, isotropic finishing, and polishing alone or in combination, are analyzed. To understand the fatigue behavior of this material, the surface finishes and internal residual stresses of the specimens are analyzed. Moreover, the fracture surface of each sample is observed by electron microscopy to determine the failure mechanism. There is a clear separation between two different types of failure: (1) rupture by a crack generated on the surface associated with high applied stress values and (2) failure by a crack generated on an internal defect associated with low applied stress values.