Optimizing corrosion resistance of Fe35Ni20Cr12Mn28Al5 high-entropy alloy: synergistic effect of Mo inhibitor, Al content and cold rolling

Purpose This study aims to investigate the corrosion behavior of cold-rolled Fe 35 Ni 20 C r12 Mn (28-x) Al x high-entropy alloys (HEAs) using the potentiodynamic polarization technique in 1 M H 2 SO 4 acid. Additionally, the influence of molybdenum (Mo) additions as inhibitors and the effect of variations in cold rolling reduction ratios and Al content on corrosion behavior are examined. Design/methodology/approach Two cold rolling reduction ratios, namely, 50% (R50) and 90% (R90), were examined for the cold-rolled Fe 35 Ni 20 Cr 12 Mn 28 Al 5 (Al 5 ) and Fe 35 Ni 20 Cr 12 Mn 23 Al 10 (Al 10 ) HEAs. Mo inhibitor additions were introduced at varying concentrations of 0.3, 0.6 and 0.9 Wt.%. The potentiodynamic polarization technique was used to evaluate the corrosion rates (CRs) under different experimental conditions. Findings The results indicate that the addition of 0.3 Wt.% Mo in 1 M H 2 SO 4 yielded the lowest CR for both R50 and R90, irrespective of the Al content in the HEAs. However, the highest CR was observed at 0.6 Wt.% Mo addition. Furthermore, increasing the concentration of Al resulted in a corresponding rise in the CR. Comparatively, the CR decreased significantly when the cold rolling reduction ratio increased from R50 to R90. Originality/value This research provides valuable insights into the intricate relationship between Mo inhibitors, cold rolling reduction ratio, Al content and the resulting corrosion behavior of Fe 35 Ni 20 Cr 12 Mn (28-x) Al x HEAs. The comprehensive analysis of corroded HEAs, including surface morphology, compositions and elemental distribution mapping, contributes to the understanding of the corrosion mechanisms and offers potential strategies for enhancing the corrosion behavior of HEAs.