Studying the nature of passivation film of a metastable compositionally complex alloy Fe39Mn20Co20Cr15Si5Al1 (at.%) in 3.5 wt.% NaCl solution

The nature of passive films influences alloy corrosion characteristics. The corrosion susceptibility of an alloy can undermine the structural integrity of any engineering component. Advanced materials, such as compositionally complex alloys (CCAs) including high entropy alloys (HEAs), are being researched for a range of applications. It has necessitated the property evaluation of such alloys in a variety of environments including stress corrosion cracking environment. The current work investigates the passivation film behavior of a transformation-induced-plasticity (TRIP) Fe₃₉Mn₂₀Co₂₀Cr₁₅Si₅Al₁ (at.%) CCA in 3.5 wt.% NaCl solution at room temperature under mechanically loaded condition. A dog-bone shaped flat tensile test coupon was subjected to linear potentiodynamic polarization measurement while loaded under tension. For comparison, another set of linear potentiodynamic polarization test was carried out on a tensile test coupon with the same geometry under no load. Following polarization test, the characterization of the passivation films under these conditions has been conducted using advanced analytical tools including electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy, before and after the corrosion test. The finding of this study will be discussed during the presentation.