Direct numerical simulation of homogeneous nucleation and growth in a phase-field model using cell dynamics method.
Direct numerical simulation of homogeneous nucleation and growth in a phase-field model using cell dynamics method.
复制标题
使用细胞动力学方法在相场模型中直接数值模拟均匀成核和生长。
DOI：
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发表时间：
2008
影响因子：
4.4
通讯作者：
M. Iwamatsu
中科院分区：
文献类型：
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作者：
M. Iwamatsu
使用细胞动力学方法对最简单的二维相场模型中的均匀成核和生长进行了数值研究。对从成核到生长的整个过程进行了模拟，结果表明其严格遵循 Kolmogorov-Johnson-Mehl-Avrami (KJMA) 相变场景。具体而言，发现新稳定相的体积分数的时间演变密切遵循 KJMA 公式。通过将 KJMA 公式直接拟合到模拟数据，不仅可以定量研究 Avrami 指数，还可以定量研究成核速率的大小，特别是孵育时间的大小。修改后的 Avrami 图也用于验证导出的 KJMA 参数。发现Avrami指数接近理想理论值m=3。成核速率的温度依赖性遵循经典成核理论预期的激活型行为。另一方面，孵育时间的温度依赖性并不遵循指数激活型行为。相反，孵化时间与 Shneidman 和 Weinberg 理论预测的温度成反比 [J.非晶体。固体 160, 89 (1993)]。还讨论了在仿真中限制热噪声以推导正确的 Avrami 指数的需要。
The homogeneous nucleation and growth in a simplest two-dimensional phase field model is numerically studied using the cell dynamics method. The whole process from nucleation to growth is simulated and is shown to follow closely the Kolmogorov-Johnson-Mehl-Avrami (KJMA) scenario of phase transformation. Specifically the time evolution of the volume fraction of new stable phase is found to follow closely the KJMA formula. By fitting the KJMA formula directly to the simulation data, not only the Avrami exponent but the magnitude of nucleation rate and, in particular, of incubation time are quantitatively studied. The modified Avrami plot is also used to verify the derived KJMA parameters. It is found that the Avrami exponent is close to the ideal theoretical value m=3. The temperature dependence of nucleation rate follows the activation-type behavior expected from the classical nucleation theory. On the other hand, the temperature dependence of incubation time does not follow the exponential activation-type behavior. Rather the incubation time is inversely proportional to the temperature predicted from the theory of Shneidman and Weinberg [J. Non-Cryst. Solids 160, 89 (1993)]. A need to restrict thermal noise in simulation to deduce correct Avrami exponent is also discussed.