Microstructural Evolution and Magnetic and Corrosion Properties of FeCoNiAl0.2Yx High-Entropy Alloys

Abstract

FeCoNiAl0.2Yx (x = 0, 0.05, 0.1, 0.2, 0.3) high-entropy alloys (HEAs) with different Y contents were prepared by a vacuum arc melting method, and experimental methods such as X-ray diffraction (XRD), scanning electron microscope (SEM), vibration sample magnetometer (VSM), hardness tester, and electrochemical workstation were used. The effects of rare Earth Y content on the microstructure, magnetic properties, and electrochemical corrosion properties of the alloy were investigated. The results showed that all FeCoNiAl0.2Yx alloys had a dendrite structure. When x = 0, the alloy consists of the FCC phase, after adding Y element, the HCP2 phase appeared in the alloy, and when x = 0.3, only the HCP1 phase existed in the alloy. The hardness of the alloy increased with the increase of Y content. The FeCoNiAl0.2Y0.1 alloy had the best magnetic properties, reaching a maximum saturation magnetization strength (Ms) of 139.25 emu g−1. The hysteresis area of FeCoNiAl0.2Yx alloys was very small, basically zero, and the hysteresis curves showed a very small lag. The corrosion potential of FeCoNiAl0.2Y0.1 alloy was −1.010 V, and the minimum corrosion current density of FeCoNiAl0.2Y0.1 alloy was 1.181 × 10−5 A cm−2. FeCoNiAl0.2Y0.1 alloy had relatively high corrosion potential and minimum corrosion current density and had excellent corrosion resistance.