AUTHOR=Godlewska Elżbieta M. , Mitoraj-Królikowska Marzena , Czerski Jakub , Jawańska Monika , Gein Sergej , Hecht Ulrike 

TITLE=Corrosion of Al(Co)CrFeNi High-Entropy Alloys

JOURNAL=Frontiers in Materials

VOLUME=7

YEAR=2020

URL=https://www.frontiersin.org/journals/materials/articles/10.3389/fmats.2020.566336

DOI=10.3389/fmats.2020.566336

ISSN=2296-8016

ABSTRACT=<p>High-entropy alloys, AlCrFe<sub>2</sub>Ni<sub>2</sub>Mo<sub>x</sub> (<italic>x</italic> = 0.00, 0.05, 0.10, and 0.15), AlCoCrFeNi, and two quinary alloys with compositions close to its face-centered cubic and body-centered cubic component phases, are tested for corrosion resistance in 3.5 wt% NaCl. The materials with different microstructure produced by arc melting or ingot metallurgy are evaluated by several electrochemical techniques: measurements of open circuit voltage, cyclic potentiodynamic polarization, and electrochemical impedance spectroscopy. Microstructure, surface topography, and composition are systematically characterized by scanning electron microscopy and energy-dispersive x-ray spectroscopy. The results indicate that minor additions of Mo positively affect corrosion resistance of the AlCrFe<sub>2</sub>Ni<sub>2</sub> alloy by hampering pit formation. The face-centered cubic phase in the equimolar alloy, AlCoCrFeNi, is proved to exhibit more noble corrosion potential and pitting potential, lower corrosion current density and corrosion rate than the body-centered cubic phase. Overall behavior of the investigated alloys is influenced by the manufacturing conditions, exact chemical composition, distribution of phases, and occurrence of physical defects on the surface.</p>