Corrosion behaviors of CrFeNiNbx medium entropy alloys with hypereutectic and hypoeutectic structures

In this paper, the corrosion resistance and corresponding corrosion mechanisms of CrFeNiNbx (x = 0.2, 0.4) hypoeutectic and hypereutectic medium entropy alloys (MEAs) in 3.5 wt% NaCl solution were systematically investigated. It is found that, both CrFeNiNb0.2 and CrFeNiNb0.4 MEAs are composed of FCC and Laves phases, and they show excellent and similar corrosion resistance in 3.5 wt% NaCl solution due to ultrahigh oxidized (Cr, Nb) concentration in their passive films. However, the FCC and Laves phases in these MEAs have significant difference in corrosion behaviors, which is possibly influenced by the diversity in chemical properties and formation of passive films on these phases. This work is beneficial for designing high-performance eutectic-related MEAs with outstanding corrosion resistance.

Automated summary

The corrosion resistance and mechanisms of CrFeNiNbx (x = 0.2, 0.4) hypoeutectic and hypereutectic medium entropy alloys (MEAs) in 3.5 wt% NaCl solution were investigated. Both MEAs showed excellent and similar corrosion resistance due to the presence of ultrahigh oxidized (Cr, Nb) concentration in their passive films. However, significant differences in corrosion behaviors were observed between the FCC and Laves phases in these alloys, possibly influenced by their diverse chemical properties and formation of passive films. This study provides valuable insights for designing high-performance eutectic-related MEAs with exceptional corrosion resistance.