Grain Growth and Oxidation Resistance of Fe-Cr-Al Electrothermal Alloy Doped with Yttrium

Abstract

Received: 9 September 2019 Accepted: 17 December 2019 This paper mainly explores how the addition of yttrium (Y) affects the grain growth and oxidation resistance of Fe-Cr-Al electrothermal alloy under high temperatures. Firstly, five groups of Y-free samples of Fe-Cr-Al electrothermal alloy were prepared through hot forging, hot rolling and cold rolling, and each group was doped with different amounts of Y and treated at several temperature levels. The element distribution and cross-sectional morphology of the oxide film were obtained by scanning electron microscopy (SEM). The evolution of the oxide film was monitored in backscattering Raman configuration. According to the surface and cross-sectional morphologies and Xray diffraction (XRD) spectra, it is concluded that the addition of Y can refine the grain size, inhibit the grain growth and improve the oxidation resistance of Fe-Cr-Al alloy under high temperature, creating a continuous dense layer of oxide film on the matrix; the density and continuity of the film can be improved by adding a trace amount of Y (0.1wt.%). In this case, the film will adhere to the matrix more tightly, reducing the oxidation rate. However, a high Y dose (0.4wt.%) will thicken the oxide film and reduce the oxidation resistance of the alloy. The optimal dose of Y is 0.1wt.% for the Fe-Cr-Al alloy. The research results provide a reference for improving the performance of Fe-CrAl alloy with rare earth (RE) elements.