High-Temperature Oxidation of NbTi-Bearing Refractory Medium- and High-Entropy Alloys.

The oxidation of six NbTi-i refractory medium- and high-entropy alloys (NbTi + Ta, NbTi + CrTa, NbTi + AlTa, NbTi + AlMo, NbTi + AlMoTa and NbTi + AlCrMo) were investigated at 1000 °C for 20 h. According to our observation, increased Cr content promoted the formation of protective CrNbO and CrO oxides in NbTi + CrTa and NbTi + AlCrMo, enhancing oxidation resistance. The addition of Al resulted in the formation of AlTi-rich oxide in NbTi + AlTa.