Deciphering the role of Al$_2$O$_3$ formed during isothermal oxidation in a dual-phase AlCoCrFeNi$_{2.1}$ Eutectic High-Entropy Alloy

TL;DR

This study investigates the oxidation behavior of a dual-phase AlCoCrFeNi$_{2.1}$ high-entropy alloy at high temperatures, focusing on the formation and role of Al$_2$O$_3$ during isothermal oxidation at 950 and 1000°C.

Contribution

It provides detailed analysis of phase evolution and oxidation kinetics of AlCoCrFeNi$_{2.1}$ alloy at elevated temperatures, highlighting the role of Al$_2$O$_3$ in oxidation resistance.

Findings

Al$_2$O$_3$ forms during oxidation at high temperatures.

Oxidation follows specific rate laws at 950 and 1000°C.

Phase evolution impacts oxidation behavior and alloy stability.

Abstract

In recent times,there has been a significant volume of work on Eutectic High Entropy Alloys (EHEAs) owing to their remarkable castability combined with excellent mechanical properties,which aids in clearing obstacles for their technological applications. One of the most common EHEAs,which has been of enormous interest at present, primarily owing to its solidification and tensile behavior, is AlCoCrFeNi$_{2.1}$. However,to aim for high-temperature applications,oxidation behaviour of material is one of the major aspects that needs to be extensively investigated.To this end,the present work aims to study the phases evolved during oxidation at elevated temperatures as high as 950 and 1000$^\circ$C in AlCoCrFeNi$_{2.1}$ using XRD and also to determine the rate law followed for isothermal oxidation of this alloy at 950 and 1000$^\circ$C,in order to understand the role of Al$_2$O$_3$ phase formed during isothermal oxidation at 950 and 1000$^\circ$C.