STRUCTURAL TRANSFORMATIONS OF HEATED FERRO-BASED AMORPHOUS ALLOYS. A.S. Veksler, G.A. Kuznetsova, V.I. Boldyrev, A.L. Ivanovsky. Irkutsk State University, Institute of Applied Physics. 20 Gagarin Blvd. Irkutsk, 664003 ,Russia.

The X-radiographic investigation of thermal transformations of the structures of ferro-based X-ray amorphous alloys Fe₈₁B₁₃,₅Si_3,5C₂, Fe₇₃Co₁₂B₁₅, Fe₆₄Co₂₁B₁₅ was made. The alloys were produced by the single-roll melt quenching method in the form of ribbons 30 mkm thick, 10 mm wide. The thermal processing was being done in the mode of isothermic annealing with the air present with in the temperature range of 150-700deg. C. The phase composition of the annealed ribbons and the degree of crystallinity (the quantity of amorphous phase) were X-radiographically controlled. The functions of radial distribution of atomic density were calculated, the coordination numbers were defined.

It was stated that if the T of the heating of the ribbons is increased, the process of crystallization begins to develop, the progress of which depends on the element composition of the alloys.

Depending on the composition of the alloys at different temperatures the crystalline phases [[alpha]]-Fe, FeSi, FeSi₂, Fe₂BC; [[gamma]]-Fe, FeB,Fe₃C; [[alpha]]-Fe,[[gamma]]-Fe, FeSi, FeSi₂, FeB and Fe₂B are registered. If the amount of admixture elements is diminished, the amount of [[alpha]]-Fe in the annealed substance is increased. When the T of the heating is increased from 350 to 700deg. C the sizes of crystals are significantly increased which is shown by the diminishing of the half-width of the correspondent reflections three times approximately. The process of crystallization is very intensive at the initial stages, but when the T is 600-700deg. C, it slows down and with the modes of thermal processing applied at 700deg. C this process is not complete. The received data are in on agreement with the results of the investigation of photothermostimulated exoelectronic emission and differential thermal analysis.