High temperature oxidation of inconel 939 produced by additive manufacturing

Abstract

High temperature oxidation of additively manufactured (Laser-powder bed fusion) IN939 (AM IN939) was studied at 900 degrees C in dry air for 168 hours. AM IN939 cut parallel/perpendicular to the building direction, including conventionally manufactured (CM) IN939 were exposed to assess the influence of AM microstructure and its inherent anisotropy on oxidation properties. Microstructural anisotropy had no significant impact on oxidation properties. AM and CM IN939 exhibited nearly identical mass gains, yet local spallation was observed in the former. Further investigation involved oxidation of heat-treated AM IN939, revealing improved adhesion, possibly due to transformation of fine dendritic/cellular structure into coarse equiaxed grains.