About this Abstract |
| Meeting |
TMS Specialty Congress 2026
|
| Symposium
|
4th World Congress on High Entropy Alloys (HEA 2026)
|
| Presentation Title |
Mechanistic Insights Into Corrosion of Ultrafine- and Coarse-Grained HEAs: Roles of Grain Size and Passive Film Evolution |
| Author(s) |
Daljeet Singh, Rajiv Kumar |
| On-Site Speaker (Planned) |
Daljeet Singh |
| Abstract Scope |
This work examines the corrosion behaviour of AlCoCrFeNi-based high-entropy alloys (HEAs) in 3.5 wt.% NaCl, emphasizing the combined influence of grain size, phase constitution, and passive film chemistry. Coarse-grained (CG) HEAs produced by arc melting are compared with ultrafine-grained (UFG) alloys obtained through high-energy ball milling followed by spark plasma sintering. The CG alloys exhibit more stable passivation and lower corrosion rates. Although grain refinement accelerates passive film initiation, the UFG alloys develop high defect densities and refined multiphase structures that promote porous Al2O3 formation on BCC and strengthen micro-galvanic coupling with Cr2O3-rich FCC regions, leading to unstable passivity and pitting susceptibility. In contrast, the CG alloys form a more protective Cr-rich passive layer, particularly in the single-phase FCC composition. These findings provide mechanistic insight into how microstructural stability and phase chemistry collectively govern passivity in HEAs, guiding the design of alloys with improved corrosion performance. |
| Proceedings Inclusion? |
Undecided |