Evolution of Oxide Phases and Residual Stress in HAYNES® 282® Superalloy During Long-Term High-Temperature Oxidation

Abstract

The long-term oxidation behavior of the HAYNES^® 282^® superalloy was systematically investigated in air at temperatures ranging from 800 to 950 °C for durations of up to 720 h. The oxide phases that developed on the surface of the alloy were characterized using X-ray diffraction and energy-dispersive X-ray spectroscopy (EDS). The residual stress within the Cr₂O₃ layer was assessed utilizing the average X-ray strain method. The primary oxide phase was identified as rhombohedral Cr₂O₃, with secondary phases including rutile-TiO₂, spinel-MnCr₂O₄, and perovskite CoTiO₃. The thickness of the external oxide layer increased with both oxidation temperature and time, adhering to parabolic kinetics. EDS mapping indicated the dispersion of Al-rich and Ti-rich oxides internally, suggesting the precipitation of Al₂O₃ and TiO₂ beneath the external Cr₂O₃ layer. The activation energy for the long-term oxidation of HAYNES^® 282^® was calculated to be 272.5 ± 15.0 kJ mol⁻¹. The total residual stresses within the Cr₂O₃ phase measured at room temperature were found to be entirely compressive. The calculated intrinsic residual stress associated with Cr₂O₃ growth at 800 °C exhibited a transition from tensile to compressive, whereas at 950 °C, it remained tensile. The evolution of intrinsic stress in relation to oxidation time, temperature, and scale thickness was discussed in the context of the crystallite coalescence model and the Pilling–Bedworth ratio.