Ideally, the material properties of cast and additively manufactured components should not differ. However, the surface roughness, which depends e.g. on the energy density and part orientation, and the microstructure anisotropy of LPBF-fabricated parts significantly influence the oxidation behavior, possibly leading to higher oxidation rates. Furthermore, it has been shown in the literature that the oxidation properties of additively manufactured components differ from those of cast parts. The surface can be polished after LPBF processing to remove the rough surface caused by the partially fused powder particles, which leads to higher oxidation rates than conventionally manufactured parts. In addition to surface roughness, elongated grains in the building direction, which typically form in LPBF, can lead to faster diffusion of reactive species through grain boundary diffusion and contribute to a higher oxidation rate and larger internal oxidation zones, especially at temperatures between 600 and 900 °C, where diffusion occurs mainly along the grain boundaries. The microdendritic structure and a high dislocation density have a further influence.

The aim of this study is to investigate the microstructure-dependent oxidation behavior of additively manufactured nickel-based alloys like Alloy 80a. The powders are produced by gas atomization and additively manufactured in the LPBF process. Additiveliy manudactured and samples, respecitvely, are surface-treated and then annealed in air at temperatures between 800°C and 1000°C for up to 200 hours. The investigations are flanked by microstructure examinations in the scanning electron microscope, an analysis of the microstructures in the transmission electron microscope and chemical examinations using XRD and EDX.