Microstructure development and mechanical performance of Al2CrFeMnTi light-weight high entropy alloy

Abstract

Light-weight high entropy alloys (LWHEAs) are considered equiatomic or near-equiatomic alloys consisting of at least five elements. Low-density elements, like Al and Ti, are the key constituents in designing these alloys so that features such as reduced overall density and improved mechanical properties are achieved. A new LWHEAs (Al2CrFeMnTi) is designed, where mechanical alloying followed by subsequent casting is carried out for a successful synthesis. As a result, chemically homogenous samples are fabricated that possess a multiphase microstructure of BCC solid solution, C-14 Laves phase, and L-21 precipitates in the as-cast state. Although the presence of intermetallic phases results in high hardness characterized by nanoindentation tests, the produced alloy demonstrates some level of ductility before failure. This behavior could be linked to the minimal strain hardening of the BCC phase. Additionally, the formation of ultra-fine L-21 precipitates within the BCC phase is contributed to the high strength and the modified strain observed in the alloy.