About this Abstract |
Meeting |
2021 TMS Annual Meeting & Exhibition
|
Symposium
|
Computational Thermodynamics and Kinetics
|
Presentation Title |
Inhomogeneous Free Energies Beyond the Cahn-Hilliard Model: Interface Anisotropy and Equilibrium Patterning |
Author(s) |
Pascal M. Bellon, Qun Li, Robert S Averback |
On-Site Speaker (Planned) |
Pascal M. Bellon |
Abstract Scope |
A real-space expansion of the free energy of inhomogeneous solid solutions is considered in binary alloys with pairwise interactions. In addition to the gradient-energy inhomogeneity term introduced by Cahn and Hilliard, this expansion yields a general expression for higher order terms. The coefficients of these higher-order inhomogeneities are fourth-rank, sixth-rank … (2n)th-rank tensors, which, for cubic lattices, introduce crystalline anisotropy and thus potentially modify the equilibrium shape of precipitates. Furthermore, each interaction shell introduces its own set of inhomogeneity coefficients, and the coexistence of multiple interactions can result in competing effects on phase stability. We illustrate these analytical results using phase field simulations to study in fcc alloys with interactions from first to fourth nearest neighbors (i) the equilibrium shape of precipitates and (ii) nanoscale compositional patterning in alloys with competing interactions. We also compare these results with Monte Carlo simulations and available experimental results. |
Proceedings Inclusion? |
Planned: |