The Effect of Al on the Formation of a CrTaO4 Layer in Refractory High Entropy Alloys Ta-Mo-Cr-Ti-xAl

Abstract In this study, the effect of Al on high temperature oxidation Al-containing refractory entropy alloys (RHEAs) Ta-Mo-Cr-Ti-xAl ( x = 5; 10; 15; 20 at%) was examined. Oxidation experiments were performed in air for 24 h at 1200 °C. The kinetics alloy with 5 at% is notably affected by formation gaseous MoO 3 and CrO , while continuous mass gain detected higher concentrations. 15 form relatively thin oxide scales a zone internal corrosion due to dense CrTaO 4 interface oxide/substrate. 10 exhibit, contrary, thick porous because fast growing Ta 2 O . positive influence Cr followed growth yield compact scale explained getter nucleation effects.