Computer modeling of non-isothermal crystallization
Computer modeling of non-isothermal crystallization
复制标题
非等温结晶的计算机建模
DOI：
10.1016/0022-3093(96)00402-4
复制
发表时间：
1996
影响因子：
3.5
通讯作者：
C. Ray
中科院分区：
文献类型：
--
作者：
K. Kelton;K. Narayan;L. Levine;T. C. Cull;C. Ray
提出了一个模拟等温相变和非等温相变的计算机模型，该模型由均匀和非均相形核和界面限制生长两种方式进行。提出了一种新的处理粒度对结晶动力学影响的方法，并将其纳入到数值模型中。此外，还包括随时间变化的成核速率、与尺寸相关的生长速率和表面结晶。将模型预测与实验测量的二硅酸锂玻璃析晶的DSC/DTA峰参数随颗粒大小、铂掺杂水平和水含量的变化进行了比较。定量的一致性表明，该数值模型可以用来从容易获得的量热数据中提取关键的动力学数据。该模型还可以用来探测在其他情况下无法访问的区域中的成核和生长行为。基于对数据的拟合，证明了先前的预测，即DSC/DTA扫描中随时间变化的形核率可以在高于稳态速率峰值的温度下上升到稳态值以上。
A realistic computer model for simulating isothermal and non-isothermal phase transformations proceeding by homogeneous and heterogeneous nucleation and interface-limited growth is presented. A new treatment for particle size effects on the crystallization kinetics is developed and is incorporated into the numerical model. Time-dependent nucleation rates, size-dependent growth rates and surface crystallization are also included. Model predictions are compared with experimental measurements of DSC/DTA peak parameters for the crystallization of lithium disilicate glass as a function of particle size, Pt doping levels, and water content. The quantitative agreement that is demonstrated indicates that the numerical model can be used to extract key kinetic data from easily obtained calorimetric data. The model can also be used to probe nucleation and growth behavior in regimes that are otherwise inaccessible. Based on a fit to data, an earlier prediction that the time-dependent nucleation rate in a DSC/DTA scan can rise above the steady-state value at a temperature higher than the peak in the steady-state rate is demonstrated.