Modulating the crystallization process of Fe82B12C6 amorphous alloy via rapid annealing.

Abstract Crystallization is a uniform behavior for amorphous alloys while it can be fairly complex. For Fe-B-C alloys with high Fe content, the precipitation of α-Fe is ahead of the Fe-metalloid compounds with temperature increasing. It is found that the crystallization products of Fe-B-C amorphous alloys with Fe content lower than 82% can be modulated by appropriate annealing. The Fe 82 B 12 C 6 alloy is eutectoidally crystallized with the simultaneous precipitation of α-Fe and Fe-metalloid compounds under conventional annealing. It is a diffusion controlled three-dimensionally growth with a constant nucleation rate. However, only α-Fe nanocrystals with a low volume fraction form under rapid annealing, which is evidenced by the results of X-ray and electron diffractions along with the magnetometry. The transmission electron microscopy bright-field images show that the α-Fe nanocrystals obtained by rapid annealing have two different morphologies. One is dendritic with a large characteristic length and the other is equiaxed-like. Highlights • Single α-Fe phase is obtained under suitable rapid annealing for Fe 82 B 12 C 6 alloy. • The α-Fe nanocrystals obtained by rapid annealing have two different morphologies. • The coercivity is drastically reduced due to the absence of hard magnetic phase. [ABSTRACT FROM AUTHOR]