Atomic volumes and local structure of metallic glasses

The composition dependence of the room-temperature average atomic volume is analysed for early and late transition metal (TE-TL type) and metal-metalloid (TL-MD type) amorphous alloys. For the Zr-Cu, Ti-Cu and Hf-Ni sytems, the data suggest an ideal solid solution behaviour. For the other TE-TL systems, two composition ranges can be distinguished (20-70 at.% TL and 84-93 at.% TL). For each composition range, a specific atomic volume Va-Zr can be assigned to the Zr atoms that has the same value for any of the alloying components TL = Fe, Co and Ni. For TE-rich compositions (range 1), Va1-Zr ≈ Vhcp-Zr whereas for TL-rich compositions (range 2), Va2-Zr < Va1-Zr. For the TL atoms, whereas both Va2-TL(TE-TL) and Va-TL(TL-MD) are fairly close to the VTL values of the close-packed crystalline structures, the Va2-TL(TE-TL) values are smaller by as much as about 2-3% than the Va-TL(TL-MD) values.