COMPUTER SIMULATION OF A QUENCHED BINARY ALLOY: CLUSTER DYNAMICS OF A TWO DIMENSIONAL MODEL SYSTEM.

Of particular interest in this work is the study of the growth and evolution of microdomains of the minority phase following their nucleation, i. e. , the coarsening of grains. Obtained are the size distribution of the grains, their average size, radius and ″surface″ area as a function of time. The latter quantities appear to obey simple power laws. Included is a study of the diffusion and coagulation of individual grains and the nature of grains of critical size as discussed in nucleation theories. The object is to determine the relative importance of the different kinetic processes contributing to the coarsening of the grains; does this proceed primarily by simple atom processes where larger grains grow at the expense of smaller ones which are dissolved in the matrix ( ″Ostwald ripening″ of the grains as treated by the Lifshitz-Slyozov theory) or by effective diffusion and coagulation of grains (as first considered in the Smoluchowski coagulation of raindrops in the atmosphere).