Evolution of lattice parameter and process rates during nanocrystallization of amorphous Fe-Co-Si-B alloy

The micromechanisms controlling the formation of nanocrystalline phases from an amorphous state were investigated through detailed structural and thermodynamic analysis of phases evolved during crystallization of the amorphous Fe60Co20Si5B15 alloy. Transformation kinetics were determined from electrical resistivity measurements. The structure of the produced phases was quantitatively identified by classical structure analysis. In particular, the lattice parameter of the resulting bcc-FeCo phase was determined for all transformation stages. Kinetic parameters of the phase transformations taking place were calculated by classical kinetic Avrami analysis. The distributions of process rates and activation energies during phase transformations were analyzed. The results are correlated to the presence and content of Si in the produced phase and to the distribution of activation energies active at different stages of the transformation.