Zr and Hf microalloying in an Al-Y-Fe amorphous alloy. Relation between local structure and glass-forming ability

Anne Sadoc (1) , Maher Sabra (1) , Olivier Proux (2) , Jean-Louis Hazemann (3) , Karyn Spence (4) , Kenneth Franklin Kelton (5)

1 LPMS - Laboratoire de Physique des Matériaux et des Surfaces
2 ESRF - European Synchrotron Radiation Facility
3 NEEL - MRS - Matériaux, Rayonnements, Structure
4 Department of Physics
5 Physics

The effects of the addition of small amounts of Zr and Hf (0.5 - 3 %) on the atomic structure of Al88Y7Fe5 metallic glass were examined from extended x-ray absorption fine structure (EXAFS) experiments to better understand the influence of these microadditions on the glass forming ability of this alloy. Measurements at the Zr K and Hf LIII absorption edges have allowed the local structures around Zr and Hf atoms to be determined. The same Al environment was found for the different concentrations, consisting of a small cluster extending up to 4.5 Å around the Zr atoms and up to 6 Å around the Hf ones. Although the clustering effect is smaller in the Zr neighbourhood, a drastic shortening of the nearest Zr-Al distance is shown, providing evidence for some covalent character to the bonding, in line with the increased glass-forming ability found in the alloys made with the Zr microaddition.

Mots clés: Physical Sciences

Anne Sadoc, Maher Sabra, Olivier Proux, Jean-Louis Hazemann, Karyn Spence, et al.. Zr and Hf microalloying in an Al-Y-Fe amorphous alloy. Relation between local structure and glass-forming ability. Philosophical Magazine, 2008, 88 (17), pp.2569-2582. ⟨10.1080/14786430802385286⟩. ⟨hal-00513954⟩