On the kinetics of phase transformation of small particles in Kolmogorov's model
On the kinetics of phase transformation of small particles in Kolmogorov's model
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DOI：
10.5488/cmp.11.4.597
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发表时间：
2008-12
影响因子：
0.6
通讯作者：
N. V. Alekseechkin
中科院分区：
文献类型：
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作者：
N. V. Alekseechkin
将经典的Kolmogorov-Johnson-Mehl-Avrami(KJMA)理论推广到有限尺寸系统的情形。在几何-概率方法的框架内，解决了球域中新相体积分数的计算问题。得到了均相成核和非均相成核的解。结果表明，有限性质导致了与无限空间中体积分数随时间变化的定性区别：均匀成核过程中的Avrami指数随时间从4减小到1，即相变过程发生了减慢。所得结果尤其可用于控制非晶态粉末的晶化动力学。
The classical Kolmogorov-Johnson-Mehl-Avrami (KJMA) theory is generalized to the case of a finite-size system. The problem of calculating the new-phase volume fraction in a spherical domain is solved within the framework of geometrical-probabilistic approach. The solutions are obtained for both homogeneous and heterogeneous nucleations. It is shown that the finiteness property results in a qualitative distinction of the volume-fraction time dependence from that in infinite space: the Avrami exponent in the process of homogeneous nucleation decreases with time from 4 to 1, i.e. a slowing down of the transformation process takes place. The obtained results can be used, in particular, for controlling the crystallization kinetics in amorphous powders.