发表机构
ETH Zürich（苏黎世联邦理工学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
提出一种机电耦合多相场模型，将广义动力学关系直接整合进演化定律，能模拟铁电畴壁的非线性动力学（如Merz-Stadler定律），并支持不同序参量对的不同动力学与界面能，应用不限于铁电体。
AI 中文摘要
经典相场模型通常采用Allen-Cahn演化定律来模拟界面运动，将其视为能量梯度下降的结果。这意味着界面（例如铁电体中的畴壁）速度与其驱动力之间存在线性动力学关系。当需要模拟非线性动力学关系时（这在铁电陶瓷中很常见），就需要一种替代的演化定律，从而需要一种替代模型。在此，我们提出一个机电（应力驱动）耦合的多相场框架，具有广义动力学公式，该框架将预设的动力学关系直接整合到演化定律中。我们证明，该模型能正确演化具有指定非线性动力学（例如混合指数-幂律类型）的畴壁，遵循所谓的Merz-Stadler定律。多相场公式还允许为不同的序参量对分配不同的动力学关系和界面能，这反映了不同类型铁电畴壁的可区分特性。所提出的框架广泛适用于模拟材料中的动力学关系，其应用不仅限于铁电体。
英文摘要
Classical phase-field models typically use the Allen--Cahn evolution law to model interface motion as a consequence of energy-gradient descent. This implies a linear kinetic relation between the velocity of an interface (e.g., a domain wall in a ferroelectric) and its driving force. When nonlinear kinetic relations are to be modeled, as commonly found in ferroelectric ceramics, an alternative evolution law and hence an alternative model is needed. Here, we propose an electromechanically (stress-driven) coupled multiphase-field framework with a general kinetic formulation, which integrates a prescribed kinetic relation directly into the evolution law. We show that this model correctly evolves domain walls with the assigned nonlinear kinetics, e.g., of mixed exponential-power law type, following the so-called Merz--Stadler law. The multiphase formulation further enables distinct kinetic relations and interfacial energies to be assigned to different order-parameter pairs, which reflects the distinguishable properties of the different types of ferroelectric domain walls. The proposed framework is broadly applicable for simulating kinetic relations in materials with applications beyond ferroelectrics.
Comments41 pages, 9 figures
