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Author: Wagner, Barbara × Type: report × Subject: Phase-field model ×

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Now showing 1 - 3 of 3
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    A phase-field model for solid-state dewetting and its sharp-interface limit
    (Berlin : Weierstraß-Institut für Angewandte Analysis und Stochastik, 2014) Dziwnik, Marion; Münch, Andreas; Wagner, Barbara
    We propose a phase field model for solid state dewetting in form of a Cahn-Hilliard equation with weakly anisotropic surface energy and a degenerate mobility together with a free boundary condition at the film-substrate contact line. We derive the corresponding sharp interface limit via matched asymptotic analysis involving multiple inner layers. The resulting sharp interface model is consistent with the pure surface diffusion model. In addition, we show that the natural boundary conditions, as indicated from the first variation of the total free energy, imply a contact angle condition for the dewetting front, which, in the isotropic case, is consistent with the well-known Young's equation
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    Anisotropic solid-liquid interface kinetics in silicon: An atomistically informed phase-field model
    (Berlin : Weierstraß-Institut für Angewandte Analysis und Stochastik, 2017) Bergmann, Sibylle; Barragan-Yani, Daniel A.; Flegel, Elke; Albe, Karsten; Wagner, Barbara
    We present an atomistically informed parametrization of a phase-field model for describing the anisotropic mobility of liquid-solid interfaces in silicon. The model is derived from a consistent set of atomistic data and thus allows to directly link molecular dynamics and phase field simulations. Expressions for the free energy density, the interfacial energy and the temperature and orientation dependent interface mobility are systematically fitted to data from molecular dynamics simulations based on the Stillinger-Weber interatomic potential. The temperature-dependent interface velocity follows a Vogel-Fulcher type behavior and allows to properly account for the dynamics in the undercooled melt.
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    Anisotropy in wavelet based phase field models
    (Berlin : Weierstraß-Institut für Angewandte Analysis und Stochastik, 2014) Korzec, Maciek; Münch, Andreas; Süli, Endre; Wagner, Barbara
    Anisotropy is an essential feature of phase-field models, in particular when describing the evolution of microstructures in solids. The symmetries of the crystalline phases are reflected in the interfacial energy by introducing corresponding directional dependencies in the gradient energy coefficients, which multiply the highest order derivative in the phase-field model. This paper instead considers an alternative approach, where the anisotropic gradient energy terms are replaced by a wavelet analogue that is intrinsically anisotropic and linear. In our studies we focus on the classical coupled temperature