Elemental effects on the oxidation of refractory compositionally complex alloys

The oxidation of refractory compositionally complex alloys (RCCAs) is one of the most critical subjects for their high temperature applications. In this work, several RCCAs were systematically designed and isothermally oxidised at 1000 degrees C for up to 24 h; the elemental effects of Al, Cr, Mo, Nb Ta, Ti, V, and Zr on the oxidation of the RCCAs were studied. It was found that Al, Cr, Ti could enhance the oxidation resistance of the RCCAs by promoting the formation of rutile-type AlTaO4, CrTaO4, and their related oxides, while Zr and V formed non-protective oxides such as Nb2Zr6O17, Ta2Zr6O17, ZrTiO4, and VTa9O25, resulting in severe internal oxidation. Mo appeared to be effective in suppressing internal oxidation, but it could form non-protective MoTiTa8O25. Ta was slightly more beneficial than Nb for reducing the oxidation mass gain. This study provides insights on the elemental effects on the oxidation and guidelines for improving the oxidation resistance of RCCAs.

Automated summary

This study systematically investigates the effects of Al, Cr, Mo, Nb, Ta, Ti, V, and Zr elements on the oxidation of RCCAs. It is found that Al, Cr, and Ti can enhance the oxidation resistance of RCCAs, while Zr and V result in severe internal oxidation. Mo is effective in suppressing internal oxidation, but forms non-protective compounds. Ta is more beneficial for reducing the oxidation mass gain.