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Abstract We report on the optimization of tensile properties and fatigue behaviour of Laser Powder Bed Fusion (PBF-LB/M) -built IN718 components employing an innovative hybrid additive-subtractive technology and various heat treatments. The hybrid approach comprises PBF-LB/M with in situ high-speed milling. Double Ageing, solution and ageing treatment, as well as Hot Isostatic Pressing are used to improve ultimate tensile strength and endurance limit. As a result, the advantages of the hybrid-machined components are clearly demonstrated by their improved mechanical properties. These enhanced properties are associated to changes in microstructure, which are identified as precipitations of IN718. Furthermore, crack initiation and crack growth for high cycle numbers as well as sudden fractures are determined. The additive-subtractive manufacturing approach significantly improves the surface quality with the surface roughness being reduced to R_ a R a μ m. Superficial cracks and melting errors are excluded by this innovative hybrid approach, contributing to the improved mechanical properties. Graphical abstract
Sommer et al. (Tue,) studied this question.