Identification and quantification of microstructures formed during nanocrystallization of amorphous (Fe, Co)-Nb-(Si,...

The effect of addition of Si and variation of the Fe/Co ratio on the evolution of the nanostructure was studied in a modification of the Fe-Nb-B system. The entire system (Fe, Co)(73)Nb(7)(Si, B)(20) was prepared in an amorphous state by rapid quenching using the planar flow casting method over a wide range of Fe/Co atomic ratios, ranging from 0 to 1. Nanocrystallization was investigated by evolution of the electrical resistivity with time and temperature. The microstructural analysis was performed using transmission electron microscopy as well as electron and X-ray diffraction. The results from microscopy observations were used to determine the distribution of grain size, which in these alloys attain very small dimensions of approximately 5-8 nm. New algorithms of microscope image analysis were used for grain size determination, crucial for quantifying the microprocesses controlling nucleation and growth from the amorphous rapidly quenched phase.