The Influence of Pt on the Oxidation Behavior of Alcocrfeni2.1 Eutectic High-Entropy Alloys at 1150 ℃

Abstract

Three types of AlCoCrFeNi2.1 EHEAs (EHEA, Y-Hf EHEA, Pt-Y-Hf EHEA) were manufactured in this work. After being oxidized at 1150°C, a large amount of voids formed at the interface of oxide scale formed on conventional EHEA, causing the scale to peel off after only 10 hours of oxidation. The oxide scale formed on the Y-Hf EHEA and Pt-Y-Hf EHEA exhibited superior peeling-resistance at 1150℃. Internal oxidation of Y, Hf reactive elements is found periodically in the scale formed on Y-Hf EHEA. The formation of Y, Hf oxides leads to an increase of nearby oxygen vacancies and the growth rate of surrounding oxide. Pt element in the Pt-Y-Hf EHEA suppressed the over-doping effect of Y and Hf element, resulting in a more homogeneous and planar α-Al2O3 scale on Pt-Y-Hf EHEA.

Keywords: Oxidation, Eutectic high-entropy alloys, Reactive element, Pt modification.