Crystallization of the amorphous alloys Fe₅₀Ni₃₀B₂₀and Fe₈₀oB₂₀

Abstract

The structure and growth characteristics of crystals growing in the amorphous alloys Fe₅₀Ni₃₀B₂₀ and Fe₈oB₂₀ were studied by transmission electron microscopy and X-ray diffraction. The alloys, in the form of ribbon, were annealed for 2 h at 380° to initiate crystallization. The Fe₃B crystals in both alloys have characteristic cylindrical shapes, and their structure is b.c. tetragonal witha = 8.63å andc = 4.29å. Growth occurs by formation of columnar regions which grow outward from the center of the crystal. Twinning on {211} planes of the Fe₃B divides the crystals into gradrants. There is a small amount of alpha-iron incorporated in the crystal which has a preferred orientation relationship with the Fe₃B. From these results and the results of earlier work, it is seen that the shape and structure of the crystals depend upon the metalloids present in the alloy.