Combining phase-field crystal methods with a Cahn-Hilliard model for binary alloys
Author(s)
Balakrishna, Ananya Renuka; Carter, W Craig
DownloadPhysRevE.97.043304.pdf (4.255Mb)
PUBLISHER_POLICY
Publisher Policy
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
Terms of use
Metadata
Show full item recordAbstract
Diffusion-induced phase transitions typically change the lattice symmetry of the host material. In battery electrodes, for example, Li ions (diffusing species) are inserted between layers in a crystalline electrode material (host). This diffusion induces lattice distortions and defect formations in the electrode. The structural changes to the lattice symmetry affect the host material's properties. Here, we propose a 2D theoretical framework that couples a Cahn-Hilliard (CH) model, which describes the composition field of a diffusing species, with a phase-field crystal (PFC) model, which describes the host-material lattice symmetry. We couple the two continuum models via coordinate transformation coefficients. We introduce the transformation coefficients in the PFC method to describe affine lattice deformations. These transformation coefficients are modeled as functions of the composition field. Using this coupled approach, we explore the effects of coarse-grained lattice symmetry and distortions on a diffusion-induced phase transition process. In this paper, we demonstrate the working of the CH-PFC model through three representative examples: First, we describe base cases with hexagonal and square symmetries for two composition fields. Next, we illustrate how the CH-PFC method interpolates lattice symmetry across a diffuse phase boundary. Finally, we compute a Cahn-Hilliard type of diffusion and model the accompanying changes to lattice symmetry during a phase transition process.
Date issued
2018-04Department
Massachusetts Institute of Technology. Department of Materials Science and EngineeringJournal
Physical Review E
Publisher
American Physical Society
Citation
Balakrishna, Ananya Renuka and W. Craig Carter. "Combining phase-field crystal methods with a Cahn-Hilliard model for binary alloys." Physical Review E 97, 4 (April 2018): 043304 © 2018 American Physical Society
Version: Final published version
ISSN
2470-0045
2470-0053