Tomographic atom probe (tap) study of the chemical homogeneity in Zr based bulk metallic glasses

Amorphous alloys are characterized by the absence of atomic long range order and reveal only topological and chemical short range order. The attractive properties offered by these alloys triggered intensive microstructural investigations in the last few years. The wider supercooled liquid region in new amorphous alloys allows to explore the kinetics and thermodynamics in this region. Atomic scale chemical ordering in such alloys put great demands on the characterizing techniques. The tomographic atom probe (TAP) is proved to be currently the best experimental tool to gain information on chemical heterogeneities at the atomic scale. This technique provides direct information of the detailed morphology in real space and gives the position and chemical identity of the atoms in a small volume (typically 10x10x100 nm/sup 3/). Vitreloy 1 (Zr based bulk metallic glass) has been investigated utilizing TAP. The data from TAP has been used to investigate structural homogeneity utilizing chi-square statistical tool. These investigations showed a randomly distributed homogeneous structure. (author)