| Summary: | The high temperature oxidation behavior of NbMoTaWV refractory high entropy alloy(RHEA) prepared by arc melting was studied by static oxidation experiment, XRD and FSEM. The results reveal that the NbMoTaWV RHEA is not protective due to severe cracks in the oxide layer at 1000 ℃ and 1200 ℃. The mass gain follows a linear oxidation law. Molten oxides formed at 1400 ℃, which release the growth stress of the oxide layer and fill the holes left by the volatilization of Mo and V oxides.In the oxidation process of NbMoTaWV, oxygen diffuses into the matrix and first oxidizes with Nb and Ta in the diffusion layer to generate needle-rod like oxidation products, and then oxidizes with other alloy elements. In the subsequent oxidation process, the oxides of W are dissolved in Nb and Ta oxides, while the granular mixed oxides of Mo and V volatilize at high temperatures.
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