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MM: Fachverband Metall- und Materialphysik
MM 31: Computational Materials Modelling: Physics of Ensembles 2
MM 31.5: Vortrag
Donnerstag, 8. September 2022, 12:45–13:00, H44
Sharp phase-field modeling of isotropic solidification with a super efficient spatial resolution — •Michael Fleck and Felix Schleifer — University of Bayreuth, 95447 Bayreuth, Germany
The phase-field method provides a powerful framework for microstructure evolution modeling in complex systems, as often required within the framework of integrated computational materials engineering. However, spurious grid friction, pinning and grid anisotropy seriously limit the resolution efficiency and accuracy of these models. The energetic resolution limit is determined by the maximum dimensionless driving force at which reasonable model operation is still ensured. This limit turns out to be on the order of 1 for conventional phase-field models. Grid friction and pinning can be eliminated by a the restoration of Translational Invariance (TI) in the discretized phase-field equation. This is called the sharp phase-field method, which allows to choose substantially coarser numerical resolutions of the diffuse interface without the appearance pinning. We propose an accurate scheme to restore TI locally in the local interface normal direction. The new model overcomes grid friction and pinning in three dimensional simulations, and can accurately operate at dimensionless driving forces up to the order of 104. At one-grid-point interface resolutions, exceptional degrees of isotropy can be achieved, if further the inhomogeneous latent heat release at the advancing solid-liquid interface is mitigated. Imposing a newly proposed source term regularization the new model captures the formation of isotropic seaweed structures without spurious dendritic selection by grid anisotropy.