Fatigue assessment of as-built and heat-treated Inconel 718 specimens produced by additive manufacturing including notch effects

The fatigue behaviour of notched and unnotched specimens produced by additively manufactured Inconel 718 were analysed in the as-built and heat-treated conditions. The surfaces display high roughness and defects acting as fatigue initiation sites. In the as-built condition, fine subgrains were found, while in in the heat-treated state, the subgrains were removed and the dislocation density recovered. SN-curves are predicted based on tensile properties, hardness and defects obtained by fractography, using the (Formula presented.) -method.