High Temperature Oxidation Behavior of the AlCrFeMnTi Light-Weight High-Entropy Alloy

Abstract

Light-weight high-entropy alloys (LWHEAs) are a class of engineering materials which have attracted wide research study as well as practical attention due to their unique properties along with low density. Future development of LWHEAs demands comprehensive research studies, including those on their high-temperature oxidation behavior. In this work, the microstructure, oxidation behavior, and mechanical properties of AlCrFeMnTi LWHEA was investigated. The samples were manufactured using mechanical alloying followed by spark plasma sintering techniques. After consolidation, a three-phase microstructure was formed, containing the C14, body-centered cubic, and L2 1 phases. The oxidation behavior of the samples in an ambient atmosphere after 1, 10, 30, and 60 h at 700 and 900 °C was investigated. The oxide scale formed at 700 °C exhibits a dense and compact structure, suggesting proper protection of the underlying metal at this temperature. Even though the same oxidation kinetics was detected at these temperatures, the oxidation rate and mass gain at 900 °C are higher. The morphology, size, and distribution of the three phases remain unchanged after the oxidation test, which gives rise to preservation of the mechanical properties, namely, hardness and modulus of elasticity, at both temperatures.