Abstract
The time evolution of the phase transformation has been analysed kinetically, while the energy analysis has been utilized for slow processes such as the coarsening of precipitates in the later stage of phase decomposition. However, the limits of application of the energy analysis to description of the phase decomposition have hardly been investigated. In the present study, the progress of the nucleation of precipitates is theoretically evaluated on the basis of the energy and also the kinetic analyses. The results obtained are as follows: the minimum-energy path evaluated on the basis of the free-energy theory of microstructure proposed by us is consistent with the kinetic path calculated from the diffusion equation. This result indicates that the energy analysis is useful even for the early stage of the phase decomposition.