Influence of Building Direction on the Oxidation Behavior of Inconel 718 Alloy Fabricated by Additive Manufacture of Electron Beam Melting

This research was aimed at investigating the high temperature oxidation behavior of Inconel 718 superalloy fabricated by electron beam melting with the building direction of 0 degrees, 55 degrees and 90 degrees deviation from the Z axis of cylindrical samples. Columnar gamma-fcc phase with preferred crystal orientations was found in all specimens. With the temperature ranging from 700 to 1000 degrees C,the 0 degrees sample, symbolized by the lowest grain boundary density, and largest grain size, reveals the best oxidation performance. It is concluded that the building direction has more impact on the amount of grain boundary density than crystal orientation, which determined the oxidation resistance.