Study on high-temperature oxidation of TiZrHfNbTaV high-entropy alloy

The elemental effects and oxide layer evolutions of high-entropy alloys during oxidation have remained largely unclear. The high-temperature oxidation of equimolar refractory high-entropy alloy TiZrHfNbTaV in the air at 800–1000 °C for 1 h was investigated in terms of the oxide layer microstructure and formation mechanism. The non-dense oxides formed on the alloy surface at 800–1000 °C mainly contain TiNb2O7, providing favorable oxygen diffusion conditions. The growth of the oxide layer is influenced by the oxidation temperatures, free energy of oxides, and elemental segregation. The findings offer fundamental insights into the oxidation mechanism of the refractory high-entropy alloys.