Composition Engineering of IN800H for Electron Beam Additive Manufacturing

Alloy 800H is a high-temperature, corrosion-resistant material typically produced through wrought processing, where it develops an austenitic microstructure with carbide precipitates that enhance strength. While well-characterized in conventional forms, its behavior in additive manufacturing (AM) remains largely unexplored. The rapid solidification in AM introduces characteristics across physical scales such as complex dislocation sub-grain structures, highly textured grains, voids, cracks, microstructural heterogeneity, residual stress, and non-equilibrium phases.
This alloy is difficult to weld, therefore modifications to the chemical composition may be necessary to improve its viability for AM. During the atomization of several batches of IN800H, variations in powder chemistry occur. Each of these chemistries, all remaining within tolerances for IN800H, were used to make tensile bars using electron beam additive manufacturing. The resulting mechanical properties were then compared to one another and to those of conventionally processed 800H.