Instantaneous growth approximation describing the nanocrystallization process of amorphous alloys: A cellular automata model

A cellular automata simulation based on an instantaneous growth approximation is developed to model the nanocrystallization kinetics. In this frame, the time required for a nucleus to grow up to its maximum size is neglected in comparison with the time required for the crystallization process. This approach allows a simple interpretation of the very low values of Avrami exponent found for nanocrystallization processes, 61, in the theoretical frame of Johnson–Mehl–Avrami–Kolmogorov theory. Kinetics and microstructure predictions from the simulations are compared with experimental data for FeCoNbB alloys and a good qualitative agreement is found.