A low-cost, low-density, and corrosion resistant AlFeMnSi compositionally complex alloy

• Main Authors: S. P. O’Brien, J. Christudasjustus, L. Esteves, S. Vijayan, J. R. Jinschek, N. Birbilis, R. K. Gupta
• Format: Article
• Language: English
• Published: Nature Publishing Group 2021-03-01
• Series: npj Materials Degradation
• Online Access: https://doi.org/10.1038/s41529-021-00158-5
• ISSN: 2397-2106

Abstract A compositionally complex alloy was designed, consisting of equiatomic concentrations of four low-cost commodity elements (Al, Fe, Mn, and Si). The alloy was characterized using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The corrosion of the AlFeMnSi alloy, as evaluated using potentiodynamic polarization tests and electrochemical impedance spectroscopy in 0.6 M NaCl solution, was comparable with that of stainless steel (SS) 304L. Detailed X-ray photoelectron spectroscopy analysis was carried out, including the determination of high-resolution spectra and surface sputtering. In addition, scanning transmission electron microscopy was also used to study the surface film(s) developed after constant immersion. The AlFeMnSi alloy exhibited a unique form of ‘passivity’ that arises from the development of a silicon-rich surface film from dynamic incongruent dissolution.