VALIDITY OF AVRAMI KINETICS FOR RANDOM AND NONRANDOM DISTRIBUTIONS OFGERMS

Up to now, the time dependence of the volume fraction during a first-o rder phase transition has been often described by Avrami's model, in w hich nucleation is assumed to occur randomly in the infinite volume. I n this paper we present a computer simulation of the phase transition in order to verify the validity of Avrami's kinetics in the cases of r andom and nonrandom distribution of germ nuclei. Our results indicate that Avrami's kinetics is the correct solution, provided the distribut ion of nuclei is random and the extended volume is computed by includi ng the so-called phantom nuclei. It is also shown that the general sol ution in the form of a functional of the extended volumes is appropria te for both nucleus distributions.