Computer simulation of crystallization kinetics with non-Poisson distributed nuclei

The influence of non-uniform distribution of nuclei on the crystallization kinetics of amorphous materials is investigated. This case cannot be described by the well known Johnson - Mehl - Avrami (JMA) equation, which is only valid under the assumption of a spatially homogeneous nucleation probability. The results of computer simulations of crystallization kinetics with nuclei distributed according to a cluster and a hard-core distribution are compared with JMA kinetics. The effects of the different distributions on the so-called Avrami exponent n are shown. Furthermore, we calculate the small-angle scattering curves of the simulated structures which can be used to distinguish experimentally between the three nucleation models under consideration.