Does additive manufacturing cause intergranular oxidation attack in high-temperature alloys? Case study of Ni-base alloy IN625

Journal article, 2026

High-temperature oxidation of additively manufactured (AM) Ni-base alloy IN625 has been studied in air and Ar4 %H2-2 %H2O for up to 1000 h at 900 and 1000 degrees C. AM was produced from the same conventionally manufactured (CM) reference alloy batch to retain the chemical composition and minimize batch-to-batch variation. The AM alloy developed subsurface porosity during oxidation, but the intergranular voids remained closed and unoxidized because of good adhesion of the Cr2O3 scale to the metal. Contrary to many literature studies, AM had no effect on either the oxide growth kinetics or the oxide adherence. The chemical composition of the currently studied AM alloy close to the CM, especially the minor elements e.g. Al, Mn, Si and Ti, is believed to be the key factor preventing oxide decohesion and intergranular oxidation attack.