About this Abstract |
| Meeting |
Materials in Nuclear Energy Systems (MiNES) 2025
|
| Symposium
|
Materials in Nuclear Energy Systems (MiNES) 2025
|
| Presentation Title |
Fundamental Mechanisms and Phase Transformations in Irradiation-Induced Superlattice Formation |
| Author(s) |
Larry Aagesen, Daniel Schwen, Chao Jiang, Jian Gan, Andrea Jokisaari, Cheng Sun, Yongfeng Zhang |
| On-Site Speaker (Planned) |
Larry Aagesen |
| Abstract Scope |
Unique ordered structures known as superlattices have been observed to form in some materials under irradiation. These superlattices are composed of nanometer-sized voids or gas bubbles, depending on the type of irradiation, arranged in periodic three-dimensional arrays. These superlattices nearly always have the same symmetry as the underlying crystal structure of the material in which they are formed. The mechanism of formation of these superlattices has been debated for many years. Studies of the formation mechanism of superlattices using theoretical and computational methodologies can both contribute to improved understanding of the fundamentals of irradiation damage in materials, as well as point the way to use of irradiation to create tailored properties for functional materials. Phase-field simulations of the formation of void and gas bubble superlattices have been performed, assuming that superlattices form due to anisotropic diffusion of interstitial species and that the voids or gas bubbles form by a nucleation and growth mechanism. These simulations showed the relationship between irradiation/material parameters and superlattice morphology. Using atomic kinetic Monte Carlo simulations, a transition in the void superlattice formation mechanism from nucleation and growth to spinodal decomposition was identified with increasing irradiation dose rate. Analysis of an analytical model of superlattice formation was consistent with the simulation results. The analytical model showed that most experimental observations of superlattice formation likely occurred by the nucleation and growth mechanism, but suggested that superlattice formation could occur by spinodal decomposition in nickel. |
| Proceedings Inclusion? |
Undecided |