Modelling spinodal decomposition at the atomic scale: beyond the Cahn - Hilliard model
Modelling spinodal decomposition at the atomic scale: beyond the Cahn - Hilliard model
复制标题
在原子尺度上模拟旋节线分解：超越卡恩-希利亚德模型
DOI：
10.1088/0965-0393/4/1/005
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发表时间：
1996
影响因子：
1.8
通讯作者：
A. Gardiner
中科院分区：
文献类型：
--
作者：
J. Hyde;A. Sutton;J. G. Harris;A. Cerezo;A. Gardiner
本文用三种模型来描述Fe-Cr合金的调幅分解.这种特殊的合金系统所带来的挑战是分解的波长是纳米级的。微观结构的规模太小，期望连续近似的Cahn - Hilliard方法适用，而且，事实上，我们表明，该方法未能描述实验观察到的分解动力学。另一方面，在我们早期的工作中已经确定，动态伊辛模型非常好地描述了这种分解的动力学。在本文中，我们表明，彭罗斯模型的Spinodal分解也可以解释动力学定量。彭罗斯模型是确定性的，本质上是动态伊辛模型的平均场近似。此外，我们表明，在高温随机合金的成分变化的振幅的初始分布的形式有显着的影响，随后的动力学相分离。
In this paper three models are used to describe spinodal decomposition in Fe - Cr alloys. The challenge presented by this particular alloy system is that the wavelength of the decomposition is at the nanometre scale. The scale of the microstructure is too small to expect the continuum approximations of the Cahn - Hilliard approach to apply, and, indeed, we show that the approach fails to describe the kinetics of the experimentally observed decomposition. On the other hand it has already been established in our earlier work that the dynamic Ising model describes the kinetics of this decomposition remarkably well. In this paper we show that the Penrose model of spinodal decomposition can also account for the kinetics quantitatively. The Penrose model is deterministic and is essentially a mean-field approximation to the dynamic Ising model. In addition we show that the form of the initial distribution of amplitudes of compositional variations within the high-temperature random alloy has a significant effect on the subsequent kinetics of phase separation.