Cellular automata simulations on nanocrystallization processes: From instantaneous growth approximation to limited growth

Cellular automata simulations have been performed to simulate the crystallization process under a limited growth approximation. This approximation resembles several characteristics exhibited by nanocrystalline microstructures and nanocrystallization kinetics. Avrami exponent decreases from a value n=4 indicating interface controlled growth and constant nucleation rate to a value n~1 indicating absence of growth. A continuous change of the growth contribution to the Avrami exponent from zero to 3 is observed as the composition of the amorphous phase becomes richer in the element present in the crystalline phase. ► Low values of the Avrami exponent can be explained in terms of an instantaneous growth process or a limited growth process. ► Microstructure and kinetics predicted by cellular automata under this approximation reproduces the experimental results. ► Compositional and growth range effects are explored.