Abstract Scope |
Oxidation-resistant refractory high entropy alloys (RHEAs) which consist of refractory metal elements and oxidation-resistant metal elements, are prospective materials to sustain high-temperature oxidation up to 1000 °C or above for a long duration. In this work, the refractory elements are selected from W, Mo, Ta, V, Nb, Cr, Ti etc., while the oxidation-resistant elements are selected from Ti, Al, Cr etc., to gain different composition combinations. The single-phase equimolar oxidation-resistant RHEAs are predicted by machine learning. Then multiple single-phase bulk RHEAs are prepared by the powder metallurgy method. The oxidation experiments of RHEAs are conducted at 1000 °C for various oxidation times. The RHEAs with superior oxidation resistance are selected for the subsequent nanoscale microstructural analysis. A diffusion-controlled three-layers oxide scale model was proposed to explain the oxidation kinetics and uncover the oxidation-resistance mechanism, which assists to guide the design of oxidation-resistant RHEAs. |