SIMULATION STUDIES OF DIFFUSION-LIMITED COARSENING IN 2 DIMENSIONS

The kinetics of particle coarsening are studied by means of contour dynamics simulation in two dimensions. The current method is free from the usual restrictions, such as small area fraction, constant particle shape, and local particle motion. Growth or shrinkage of particles in a given realization is found to depend on the local environment of the particles. The concept of critical size central to the classical theories such as the LSW theory, therefore, appears to be inappropriate. Surprisingly, the ensemble-averaged macroscopic behavior is consistent with mean-field theory. The particle-size distribution (PSD) tends toward an asymptotic shape, different from the mean field result. The normalized width of the PSD seems to be insensitive to volume fraction. Interfacial transport limitation can be significant for small particles, and it has the effect of altering the width of the PSD. The coarsening rate constant is found to be a function of the area fraction.