High Temperature Oxidation Property of Al0.5FeCoCrNi (Si0.2,Ti0.5) High Entropy Alloys

High-entropy alloys Al0.5FeCoCrNi, Al0.5CoCrFeNiSi0.2 and Al0.5FeCoCrNiTi0.5 were prepared by the arc melting and casting method (subscript indicats molar ratio). The oxidation resistance of the three high-entropy alloys at 900 ℃ were studied. The morphology composition and structures of the oxide scales on alloys were characterized by scanning electron microscopy (SEM) attached with energy dispersive X-ray spectrometer (EDS) and X-ray diffraction (XRD). The results show that three kinds of high-entropy alloys all belong to the oxidation resistant grade. The oxidation mass gain curves of Al0.5FeCoCrNi and Al0.5FeCoCrNiSi0.2 are similar, the velocity of the oxidation mass gains of Al0.5FeCoCrNiTi0.5 is faster. The oxides of Al0.5FeCoCrNi and Al0.5FeCoCrNiSi0.2 Cr2O3 with a small amount of AlN particles inside; the oxides of high-entropy alloy Al0.5FeCoCrNiTi0.5 are complex, there covered CoFe2O4 spinel and mixed oxides with a small amount of nitrideinside.