A dynamic phase-field model for structural transformations and twinning: Regularized interfaces with transparent prescription of complex kinetics and nucleation. Part II: Two-dimensional characterization and boundary kinetics
A dynamic phase-field model for structural transformations and twinning: Regularized interfaces with transparent prescription of complex kinetics and nucleation. Part II: Two-dimensional characterization and boundary kinetics
复制标题
DOI：
10.1016/j.jmps.2015.05.001
复制
发表时间：
2015-12-01
影响因子：
5.3
通讯作者：
Dayal, Kaushik
中科院分区：
文献类型：
--
作者：
Agrawal, Vaibhav;Dayal, Kaushik
一篇配套论文提出了相场模型的公式，即，一种具有规则化界面的模型，不需要明确的数值跟踪-允许简单和透明地规定复杂的界面动力学和成核。关键成分是能量密度的重新参数化，以明确分离成核动力学;和来自界面守恒声明的演化定律。这使得通过守恒定律的源项和通过界面速度场的动力学的成核的明确处方。该模型克服了现有相场模型的一个重要缺点，即动力学和成核的规范是限制性的和非常不透明的。在本文中，我们提出了一些数值计算-在一个和两个维度-表征我们的配方。这些计算说明了（i）高度敏感的速率相关的成核;（ii）独立的处方的前向和向后的成核应力，而不改变能量景观;（iii）粘滑界面动力学;（iii）在确定最终的微观结构状态的成核和动力学之间的竞争;（iv）各向异性动力学的影响;和（v）非单调动力学的影响。这些计算表明，这种配方的能力，精确地规定复杂的成核和动力学在一个简单和透明的marty.We还扩展我们的守恒声明来描述微观结构的界面和边界之间的连接线的动力学。这使我们能够规定一个额外的动力学关系的边界，我们检查之间的相互作用的散装动力学和结动力学。(C)2015爱思唯尔有限公司版权所有。
A companion paper presented the formulation of a phase-field model - i.e., a model with regularized interfaces that do not require explicit numerical tracking - that allows for easy and transparent prescription of complex interface kinetics and nucleation. The key ingredients were a re-parametrization of the energy density to clearly separate nucleation from kinetics; and an evolution law that comes from a conservation statement for interfaces. This enables clear prescription of nucleation through the source term of the conservation law and of kinetics through an interfacial velocity field. This model overcomes an important shortcoming of existing phase-field models, namely that the specification of kinetics and nucleation is both restrictive and extremely opaque.In this paper, we present a number of numerical calculations - in one and two dimensions - that characterize our formulation. These calculations illustrate (i) highly-sensitive rate-dependent nucleation; (ii) independent prescription of the forward and backward nucleation stresses without changing the energy landscape; (iii) stick-slip interface kinetics; (iii) the competition between nucleation and kinetics in determining the final microstructural state; (iv) the effect of anisotropic kinetics; and (v) the effect of non-monotone kinetics. These calculations demonstrate the ability of this formulation to precisely prescribe complex nucleation and kinetics in a simple and transparent manner.We also extend our conservation statement to describe the kinetics of the junction lines between microstructural interfaces and boundaries. This enables us to prescribe an additional kinetic relation for the boundary, and we examine the interplay between the bulk kinetics and the junction kinetics. (C) 2015 Elsevier Ltd. All rights reserved.