Corrosion behaviors and passive film properties of a newly developed cost-effective AlCrFeNi eutectic high entropy alloy in different corrosive solutions

Eutectic high entropy alloys (EHEAs) are of great interest among the scientific community because of their excellent combination of strength and ductility. The mechanical properties of various EHEAs were extensively studied in previous studies; however, investigations on corrosion behaviors and passive film properties of EHEAs in different corrosive solutions were relatively few. In this work, the corrosion behaviors and film properties of a newly developed cost-effective AlCrFe1.5Ni2.6 EHEA in solutions of 3.5 wt% NaCl, 0.5 M H2SO4 and 0.5 M HCl were investigated by combining electrochemical measurements and surface characterization techniques; furthermore, the results were compared with those obtained in AlCoCrFeNi2.1 EHEA. The results showed that AlCrFe1.5Ni2.6 EHEA exhibited better corrosion resistance abilities in three different corrosive solutions compared to AlCoCrFeNi2.1 EHEA, which was due to the higher fraction of the corrosion resistant FCC phase in the alloy and a more compact and protective passive film with a higher oxides/hydroxides ratio formed on the surface. The present work will provide guidance for designing EHEAs with a combination of excellent mechanical properties and good corrosion resistance abilities.