Investigation on the microstructure and microhardness of Inconel 825 thick wall fabricated by wire arc additive manufacturing

Abstract

In this study, wire arc additive manufacturing based on cold metal transfer was used to fabricate the Inconel 825 alloy thick wall. With no visible defects, the deposition was mainly consisted of Ni-Cr-based γ-phase matrix. The grain morphology in terms of size, shape and orientation, and hardness property were varied along the build direction. Columnar dendrites are the major grains found with varying sizes and orientations due to different heat transfer modes. The microhardness at top layer with fine grains exhibited a higher value of 239.9 HV, and middle layer with columnar grains exhibited a lower value of 174.7 HV.