High-Temperature Oxidation Properties and Microstructural Evolution of Nanostructure Fe-Cr-Al ODS Alloys

The oxidation behavior and microstructural evolution of the nanostructure of Fe-Cr-Al oxide dispersion strengthened (ODS) alloys prepared by spark plasma sintering were investigated by high-temperature oxidation experiments in air at 1200 °C for 100 h. The formation of Al2O3 scale was observed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS) line scans. The oxidation rate of Fe-Cr-Al ODS alloys is lower than that of conventional Fe-Cr-Al alloys, and the oxide layer formed on the Fe-Cr-Al alloy appeared loose and cracked, whereas the oxide layer formed on the Fe-Cr-Al ODS alloys was adherent and flat. This is due to the high density of dispersed nano-oxides hindering the diffusion of Al element and the formation of vacancies caused by them. In addition, the nano-oxides could also adhere to the oxide layer. Besides, the microstructure of the Fe-Cr-Al ODS alloy had excellent stability during high-temperature oxidation.