Effects of rare earth elements on AlCoCrFeNi2.1 eutectic high-entropy alloy

In order to explore the effect of rare earth elements (REEs) on the eutectic high-entropy alloys (EHEAs), 0.2 atomic per cent of Sc, Y, and La elements were added to the AlCoCrFeNi2.1(REE0) EHEA in this work. The phase composition, element distribution, electrochemical properties and mechanical properties of the alloys were analysed. The results showed that the AlCoCrFeNi2.1-based HEAs are still composed of Co, Cr, Fe (face-centred cubic)-rich phase and Al, Ni (face-centred cubic)-rich phase. After Sc, Y, La were added, Ni2Sc, Al2Y, Al2La and other intermetallics were formed in the AlCoCrFeNi2.1 alloy. In addition, it was proved that Y element can promote the formation of hexagonal close-packed (HCP) phase. AlCoCrFeNi2.1Y0.2(Y0.2) alloy has excellent corrosion resistance. AlCoCrFeNi2.1Sc0.2(Sc0.2) alloy has the best mechanical properties.