About this Abstract |
| Meeting |
2026 TMS Annual Meeting & Exhibition
|
| Symposium
|
Environmental Degradation of Multiple Principal Component Materials
|
| Presentation Title |
The third element effect on Aqueous Passivity in Cr containing 3-d Transition based Ternary, Quaternary, and Compositionally Complex Alloys |
| Author(s) |
Debashish Sur, Peter F. Connors, John R. Scully |
| On-Site Speaker (Planned) |
Debashish Sur |
| Abstract Scope |
Since the 1950s, Cr has been the key element enabling passivity in solid solution alloys like stainless steels and superalloys by forming Cr₂O₃-rich films, requiring a classical threshold of >13 at.% Cr. C. Wagner showed that Cr can enable Al₂O₃-scale formation in high-temperature Fe/Ni-Cr-Al alloys by reducing the Al threshold—a third element effect. Inspired by this, we asked: Can Al induce a similar effect for Cr in aqueous passivation? Testing Fe, Co, Ni-based ternary as well as compositionally complex alloys with Cr and lightweight elements (Al, Si, Ti), we found that Cr thresholds for passivity dropped below 13 at.% with these additions. Surface analyses revealed enhanced Cr(III) oxide enrichment and base metal oxide suppression, indicating a third element effect type behavior. We propose two governing mechanisms —kinetic enhancement of passivation and altered Cr-Cr chemical short-range ordering achieved from alloying —providing new pathways for designing corrosion-resistant alloys in the future. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Environmental Effects, High-Entropy Alloys, Sustainability |