High-Temperature Oxidation Behaviour of High Entropy Alloys

Abstract

High-temperature operation, such as in gas turbine engines, is typically limited by the ability of materials to withstand extreme operating conditions. The need for a combination of high-temperature strength and oxidation resistance, as well as microstructural stability, has led to the continued use of nickel-based superalloys as materials for turbine blades, the most critical component in aero gas turbine engines. Due to their limited melting points, materials beyond superalloys are needed to meet increasing fuel efficiency requirements. High entropy alloys have recently been considered as candidates for materials to replace nickel-based superalloys. This paper discusses the microstructures and high-temperature oxidation behavior of Al0.75CoCrCuFeNi high entropy alloy at 900, 1000, and 1100°C. It was found that the oxidation rate constants for Al0.75CoCrCuFeNi oxidized at 900, 1000, and 1100°C are 3.84 x 10-10, 5.99 x 10-10, and 8.97 x 10-10 (mg/cm2.s), respectively, with an activation energy for oxidation of 66.58 kJ/mol.