Test of the Kolmogorov-Johnson-Mehl-Avrami picture of metastable decay in a model with microscopic dynamics
- Department of Physics, University of Puerto Rico, Mayaguez, Puerto Rico 00681 (United States)
- Center for Materials Research and Technology, Department of Physics, and Supercomputer Computations Research Institute, Florida State University, Tallahassee, Florida 32306-4350 (United States)
- Supercomputer Computations Research Institute, Florida State University, Tallahassee, Florida 32306-4130 (United States)
The Kolmogorov-Johnson-Mehl-Avrami (KJMA) theory for the time evolution of the order parameter in systems undergoing first-order phase transformations has been extended by Sekimoto to the level of two-point correlation functions. Here, this extended KJMA theory is applied to a kinetic Ising lattice-gas model, in which the elementary kinetic processes act on microscopic length and time scales. The theoretical framework is used to analyze data from extensive Monte Carlo simulations. The theory is inherently a mesoscopic continuum picture, and in principle it requires a large separation between the microscopic scales and the mesoscopic scales characteristic of the evolving two-phase structure. Nevertheless, we find excellent quantitative agreement with the simulations in a large parameter regime, extending remarkably far towards strong fields (large supersaturations) and correspondingly small nucleation barriers. The original KJMA theory permits direct measurement of the order parameter in the metastable phase, and using the extension to correlation functions one can also perform separate measurements of the nucleation rate and the average velocity of the convoluted interface between the metastable and stable phase regions. The values obtained for all three quantities are verified by other theoretical and computational methods. As these quantities are often difficult to measure directly during a process of phase transformation, data analysis using the extended KJMA theory may provide a useful experimental alternative. {copyright} {ital 1999} {ital The American Physical Society}
- OSTI ID:
- 336679
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 59, Issue 14; Other Information: PBD: Apr 1999
- Country of Publication:
- United States
- Language:
- English
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