The effect of annealing temperature on the microstructure, mechanical and electrochemical properties of arc-melted AlCrFeMnNi equi-atomic High entropy alloy

In this work, an equiatomic AlCrFeMnNi high entropy alloy (HEA) was fabricated through an arc-melting and casting process. As-cast alloy ingot was annealed for 2 h at various temperatures to investigate the effect of heat treatment temperature on the microstructure, mechanical performance and electrochemical behaviour of the alloy. The morphology of the as-cast HEA consisted of interdendritic rich-Al + Ni BCC (B2) phase and majority dendritic matrix consisting largely of rich-Cr BCC phase. Annealing higher than 400 degrees C, promoted the formation of FCC structure which increased in volume to 800 degrees C. Increase in heat treatment temperature coarsened the grains leading to a decrease in hardness and increase in coefficient friction. A good combination of strength and ductility was observed when annealing was performed at 600 degrees C. Anticorrosion properties were improved after annealing. However, high-temperature annealing lowered corrosion resistance due to the galvanic effect. The alloys demonstrated high corrosion rate in acidic condition. (C) 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).