High Temperature Oxidation Behavior of Additively Manufactured Ni-base alloys: A Review

The high-temperature oxidation behavior of additively manufactured (AM) nickel-based alloys is critically reviewed, with emphasis on the role of AM-induced microstructural features such as high grain boundary density, residual stresses, porosity, crystallographic texture, and chemical segregation. These features formed mainly due to non-equilibrium solidification of the alloys significantly influence the oxidation kinetics, oxide scale morphology, and degradation mechanisms compared to their conventionally processed counter parts. The review also examines the effects of processing parameters—including build orientation, surface roughness, scan strategy, and energy density—along with post-processing treatments such as heat treatment and hot isostatic pressing on oxidation resistance. Particular attention is given to the formation and evolution of oxide scales, especially chromia- and alumina-based protective layers, and their dependence on diffusion pathways and microstructural heterogeneity. The role of elemental segregation and minor alloying elements in controlling oxide stability, adherence, and long-term performance is also discussed. While AM alloys often exhibit oxidation behavior comparable to their wrought counterparts, variations arise due to process-induced defects and compositional inhomogeneities. Post-processing treatments are shown to significantly enhance oxidation resistance by reducing porosity, homogenizing chemistry, and promoting the formation of dense, adherent oxide scales, thereby improving high-temperature durability.