High-temperature Oxidation Behavior of NbZrTiTa High-entropy Alloy

The high-temperature oxidation behavior of NbZrTiTa high-entropy alloy (HEA) was characterized by cyclic oxidation test, XRD and SEM. The results reveal that the oxidation kinetics curve of NbZrTiTa HEA in the temperature range of 1000 similar to 1400 degrees C satisfies the parabolic law. The oxidation rate constant and oxidation activation energy achieve 1.1x10(-7)similar to 1.0x10(-6) g(2).cm(-4).s(-1) and 97 kJ/mol, respectively. The oxidation type is internal oxidation. During high-temperature oxidation, oxygen diffuses along the TiZr-rich region with the severe lattice distortion and a large number of dislocations, and then reacts with the metal components to form unsaturated oxides and saturated oxides sequentially. Because of the high activity of constituent elements and the severe lattice distortion, NbZrTiTa HEA displays an extremely high oxidation activity, thus exhibiting strong potential as structure energetic material.