相场法模拟低体积分数下的Ostwald熟化

Phase-field Simulation of Ostwald Ripening in the Low Volume Fraction Fegime

建立低体积分数下的Ostwald熟化过程的相场模型,采用Cahn-Hilliard方程和Allen-Cahn方程控制相对密度场和长程取向场的变化,研究体积分数对生长指数m、动力学系数k和粒径分布的影响。结果表明:低体积分数(小于10%)的Ostwald熟化中,生长指数函数中的生长指数m不依赖于体积分数的变化,m=3.0;而随着体积分数的增加,动力学系数k变化不大,在k=0.003附近。随着熟化相体积分数的增加,晶粒生长尺寸分布加宽。

The phase field model is established to simulate Ostwald ripening in the low volume fraction regime.The changes in the relative density field and long-range orientation field are governed by Cahn-Hilliard equation and Allen-Cahn equation to study the effects of volume fraction on the growth exponent m,the kinetic coefficient k and the size distribution.The results show that the growth exponent m is equal to 3,independent from the volume fraction,while there are little changes in the kinetic coefficient k,which is near 0.003,as the volume fraction increases.The shape of size distribution broadens with increasing volume fraction of the coarsening phase.