About this Abstract |
| Meeting |
2027 TMS Annual Meeting & Exhibition
|
| Symposium
|
Materials and Chemistry for Molten Salt Systems
|
| Presentation Title |
Beyond Kirkendall Voids: Grain Boundary Assisted Bulk Dealloying in Molten Fluoride Salt |
| Author(s) |
Weiyue Zhou, Hooman Gholamzadeh, Lei Ding, Kevin Daub, Mehdi Mosayebi, Travis Casagrande, Yingxin Zhu, Miaomiao (Mia) Jin, Mark R. Daymond, Yang Yang, Michael P. Short, Suraj Y. Persaud |
| On-Site Speaker (Planned) |
Weiyue Zhou |
| Abstract Scope |
Molten fluoride salts are promising high-temperature heat-transfer media and electrochemical solvents, yet the corrosion mechanisms of structural alloys remain incompletely understood. Recent work has shown that grain-boundary porosity can arise through one-dimensional wormhole corrosion rather than intergranular Kirkendall voiding. However, the origin of porosity distributed over extended volumes remains unclear and has traditionally been attributed to Kirkendall diffusion-based void evolution. Here, using Ni–Cr alloys corroded in oxidizing FLiNaK, we show that features appearing as Kirkendall voids in two-dimensional cross-sections may instead represent sections through interconnected three-dimensional tunnels, as revealed by correlated three-dimensional FIB–SEM tomography, EBSD, and EDX. Through the coupled evolution of diffusion-induced recrystallization, diffusion-induced grain-boundary migration, and interconnected porosity in a manner reminiscent of discontinuous precipitation, two-dimensional grain boundaries can drive volumetric microstructural evolution, a mechanism we term grain-boundary-assisted bulk dealloying. These findings provide a mechanistic framework for interpreting and controlling penetrating corrosion in molten-salt systems. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Environmental Effects, Nuclear Materials, High-Temperature Materials |