EFFECT OF Nb ON CRYSTALLIZATION KINETICS OF Fe-Co-Nd-B AMORPHOUS ALLOYS
Nb对非晶态Fe-Co-Nd-B合金的晶化动力学的影响

The addition of 4% niobium in Fe-Co-Nb--B amorphous alloy may retard the crystallization process, raise the crystallized temperature and enhance the thermal stability. The nucleation of Fe3B crystallized phase is checked while the nucleation and growth of Fe23B6 phase is promoted. The average grain sizes can be reduced from 30-60 nm to about 14-20 nm. The crystallization activation energy calculated by the onset crystallization temperatures decreases obviously. The nucleation process of α-Fe(Co), Fe3B and Nd2(Fe, Co)14B phases is more difficult than the growth process, while the growth process of α-Fe(Co), Fe23B6 and Nd2(Fe, Co)14B phases is more difficult than the nucleation process caused by the addition of niobium. However, the mechanism of the nucleation and growth of the crystallized phases is almost unchanged. The crystallization process is mainly dominated by one-dimensional nucleation and three--dimensional growth with decreasing nucleation rate.