KINETICS OF NANOCRYSTALLIZATION IN METALLIC GLASSES

Primary crystallization of the excess metal in some amorphous alloys gives rise to nanocrystalline materials of great technological interest, but the kinetics of such process is reluctant to fit any of the commonly used expressions. In this work, the kinetics of the nanocrystallization has been studied by means of new equations taking into account the changes in composition of the amorphous matrix during the process. Experimental DSC data have been obtained from FeNbSiBCu alloys of the FINEMET type. A simplified model which allows a continuous change of the apparent activation energy during the nanocrystallization, is able to fit both isothermal and non isothermal DSC peaks with single sets of parameters for each composition.