Influence of nano-Y2O3 addition on the mechanical properties of selective laser melted Inconel 718

Abstract

There has been limited research on Ni-based oxide dispersion strengthened (ODS) alloys. To alleviate the drawbacks of the traditional ODS alloy manufacturing method, selective laser melting technology was chosen in this study to successfully manufacture ODS Inconel 718-Y2O3 alloys. Y2O3 nanoparticles were mixed with Inconel 718 powder at different weight percentages (0, 0.4, 1.0, and 1.5 wt%) using low energy ball milling. Using this method, the Y2O3 nanoparticles were homogeneously distributed throughout the Inconel 718 matrix. The mechanisms, in which the added Y2O3 nanoparticles combined with carbonitride precipitates to form complex precipitates consisting of Ti–Nb–Y–N–C–O were discussed. At 1.0 wt% of Y2O3 addition, a finer Laves phase was obtained, along with some grain refinement effect. The optimum amount of nanoparticles was found to be 1.0 wt% in which, interestingly, the material's elongation improved instead of its strength. On the other hand, 1.5 wt% of Y2O3 addition was found to be excessive, as it led to a significantly thicker Laves phase and coarser grains. As a result, both the strength and elongation of the samples were affected negatively.