Abstract
A synergistic strategy combining quasi-continuous-wave (QCW) laser in-process control with post-deposition homogenization treatment is proposed to tailor the dendritic structure of additively manufactured Inconel 718 for oxidation performance improvement. In the as-built state, preferential interdendritic oxidation persists, attributed to the promoted decomposition of high-energy eutectic γ phase and short-circuit diffusion at the heterogeneous eutectic γ/Laves phase interface. Interestingly, the QCW-induced fine equiaxed dendritic structure exhibits a superior homogenization response. The fine eutectic phases dissolve more rapidly owing to their reduced aspect ratio and increased shape factor, while the narrower dendritic spacing shortens the long-range diffusion distance. Following homogenization at 1060 °C for 1 h, preferential interdendritic oxidation is effectively eliminated, and its oxidation kinetics matches that of the wrought counterpart.