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

Zhengyuan Li,Haoyu Zhang,Siyu Liu,Lijia Chen

doi:10.3390/ma14030526

Zhengyuan Li, Haoyu Zhang + Show 2 more

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https://doi.org/10.3390/ma14030526

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Journal: Materials	Publication Date: Jan 22, 2021
Citations: 4	License type: CC BY 4.0

Affiliation: Shenyang University of Technology

Abstract

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.

Highlights

Fe-Cr-Al alloys are considered one of the Accident Tolerant Fuel (ATF) technologies for future advanced fission [1,2,3]
The results show that proper Zr and O ratios decelerate the oxidation rate
A compact and smooth oxide film was formed on the surface of the Fe-Cr-Al oxide dispersion strengthening (ODS) alloy

Summary

Introduction

Fe-Cr-Al alloys are considered one of the Accident Tolerant Fuel (ATF) technologies for future advanced fission [1,2,3]. This material has excellent resistance to high-temperature oxidation due to the formation of alumina film on the surface. The high-temperature oxidation resistance of Fe-Cr-Al alloys is significantly affected by the content of Cr and Al elements. In order to increase the high-temperature strength, an oxide dispersion strengthening (ODS) phase (Y2 O3 ) is added to Fe-Cr-Al alloys [10,11]. Only adding Y2 O3 alone will lead to a limited increase in the strength as a result of the formation of coarse Y-Al-O particles

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