About this Abstract |
| Meeting |
Materials in Nuclear Energy Systems (MiNES) 2025
|
| Symposium
|
Materials in Nuclear Energy Systems (MiNES) 2025
|
| Presentation Title |
The Effect of Alloy Composition on Mechanisms of Helium and Vacancy Diffusion in MoNbTaTi High Entropy Alloys |
| Author(s) |
Katie Karl, Mary Alice Cusentino, Brian Wirth |
| On-Site Speaker (Planned) |
Katie Karl |
| Abstract Scope |
The evolution of helium (He) induced structural property changes in fusion materials is controlled via the ability of He to migrate and diffuse through the host lattice, the presence of vacancies as trapping sites, and the existence of matrix inhomogeneities capable of promoting heterogeneous bubble nucleation. The excess production of helium in fusion systems necessitates increased radiation tolerance of structural materials regarding He bubble formation, coalescence, and migration. High entropy
alloys (HEAs) may possess properties capable of altering the nucleation and growth schemes of He bubbles in metals due to their complex structure and diffusional landscape. Designing complex alloys with a higher resistance to He-induced macroscopic property degradation requires a mechanistic understanding of He diffusion and clustering in complex energy landscapes. This work seeks to explore the impact of HEA composition on properties of He and vacancy diffusion in a body-centered cubic MoNbTaTi HEA. Density Function Theory is used to calculate distributions of formation
and migration energies for multiple MoNbTaTi compositions. The low solubility of He in metals suggests that He may preferentially diffuse to areas with more available free volume. This concept is examined by comparing He formation and migration energies with the atomic volume occupied by He in various alloy compositions. Elastic dipole
tensors are also calculated, allowing for the investigation of elastic interactions that may influence the energetics of He cluster formation, stability, and interaction distances in various HEA compositions. |
| Proceedings Inclusion? |
Undecided |