| About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
|
| Symposium
|
Computational Thermodynamics and Kinetics
|
| Presentation Title |
Nonequilibrium Nanoscale Patterns and Negative Effective Interface Energy: A Phase Field Approach |
| Author(s) |
Pascal M. Bellon, Qun Li, Robert S. Averback |
| On-Site Speaker (Planned) |
Pascal M. Bellon |
| Abstract Scope |
Nanostructured states can be stabilized at equilibrium in alloys where attractive short-range interactions compete with repulsive long-range interactions. This nanostructuration can be extended to steady-state dynamical systems described by effective interactions, e.g., for alloys under irradiation. Nanostructuration is associated with the spontaneous formation of interfaces from a macroscopic phase, thus suggesting a negative effective interfacial energy. We analyze this hypothesis by considering a Cahn-Hilliard phase-field model augmented with a Laplacian-square inhomogeneity term to capture effective long-range interactions. Analytical modeling and phase field simulations indicate that, in the patterning regime the interface free energy is indeed negative but also scale-dependent, raising questions about defining interface energy as an excess quantity. It is proposed that a more consistent description is achieved by introducing an interfacial compressibility as a conjugate variable of the patterning lengthscale. This concept is used to predict capillary effects near curved interfaces and compared with phase field simulation results. |
| Proceedings Inclusion? |
Planned: Supplemental Proceedings volume |