Abstract
The effects of Al and Ti contents on the microstructures and high temperature properties of AlxCo1.5CrFeNi1.5Tiy (x, y values in molar ratio, x + y = 0.5) high entropy alloys have been investigated. With an increase in Al content and a decrease in Ti concentrations, precipitated phases in the FCC high entropy γ matrix can evolve from η to γ′ to β phases. Some of these alloys can possess high hardness values at elevated temperatures due to γ′ precipitations, and continuous Cr2O3 can form on the surfaces of these alloys for protection against oxidation. This study can serve as a guideline for future high entropy alloy design for high temperature applications.