Strategic design of oxidation-resistant nickel-based superalloys: Comparative study of enhancing mechanism of Y2O3 doping and Y alloying on the high-temperature oxidation

Abstract

Nickel-based superalloys fabricated via laser powder bed fusion (LPBF) suffer from microsegregation and microdefects due to rapid solidification, which destabilize the oxidation protective layer and accelerate high-temperature oxidation, severely deteriorating their oxidation resistance during high-temperature service. In this work, two distinct powder processing strategies, Y₂O₃ nanoparticles doping and Y element alloying, were employed to enhance the high temperature oxidation resistance of LPBF Hastelloy X (HX) nickel-based alloy through targeted microstructural engineering. The results show that both Y₂O₃-doping (HX-Y₂O₃) and Y-alloying (HX-Y) can enhance the high-temperature oxidation resistance of HX alloy. Compared to the HX sample, the parabolic oxidation rate constant of the HX-Y₂O₃ and HX-Y samples decrease from 12.46 × 10⁻³ mg² cm⁻⁴ h⁻¹ to 1.45 × 10⁻³ mg² cm⁻⁴ h⁻¹ and 0.2312 × 10⁻³ mg² cm⁻⁴ h⁻¹, respectively. Y₂O₃ nanoparticles provide extra nucleation sites for oxidation products, contributing to the rapid formation of dense oxide layers. As for the HX-Y alloy, the Y element can effectively occupy the grain boundary (GB) vacancies and reduce the diffusion rate of the oxide-forming elements, thus significantly reducing the oxidation rate and improving the adherence and the resistance to spallation of the oxide layer. This study establishes a fundamental framework correlating powder processing strategies with oxidation protection mechanisms. The findings provide generalized guidelines for designing oxidation-resistant additive manufacturing (AM) alloys through targeted microstructural engineering during powder processing. Furthermore, the developed principles demonstrate substantial potential for extension to other oxidation-susceptible alloy systems.