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, ⩽1, 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.