Abstract
A model is developed for homogeneous phase-transition kinetics in a system for which multiple secondary phases are simultaneously growing from a supersaturated primary phase. The approach is entirely kinematical in nature, with no account being taken of the actual physics of the nucleation/growth process. Randomly dispersed nuclei are assumed to act as growth centers for each of the respective phases, which grow at time-dependent rates that are generally different for different phases. Expressions are derived for the time-dependent volume fraction occupied by all the phases as well as by each individual phase. The results are illustrated by application to a simple example.