STRUCTURE ANALYSES OF AMORPHOUS MELT-SPUN FE-ZR-(B,SI) ALLOYS AND MECHANICALLY ALLOYED FE-ZR POWDERS

Melt-spun amorphous zirconium-rich Fe-Zr alloys with metalloid additions (B, Si) and mechanically alloyed amorphous Fe-Zr powders were investigated by X-ray diffraction and Moessbauer spectroscopy. The comparison of the radial distribution functions G(r) of ternary Fe-Zr-(B, Si) alloys with the data for binary Fe-Zr glasses establishes the influence of boron and silicon additions on the structure of the amorphous state. Moreover, in (Fe24Zr76)-B alloys, an increasing boron content strongly influences the crystallization behaviour and leads to a stabilization of the glass. Whereas the G(r) of the as-prepared mechanically alloyed Fe30Zr70 powder is similar to that of corresponding melt-spun Fe-Zr ribbons, a relaxation treatment at 150°C causes significant changes in G(r) of the Fe30Zr70 powder. The crystallization behaviour of this powder differs from that of zirconium-rich melt-spun Fe-Zr ribbons; Zr2Fe, a well-known metastable phase identified in the crystallization sequence of melt-quenched glasses, does not occur in the powder samples.