Regensburg 2004 – scientific programme

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M: Metallphysik

M 18: Postersitzung

M 18.3: Poster

Tuesday, March 9, 2004, 14:30–16:30, Saal C

Tomographic atom probe (TAP) study of the chemical ordering in Zr60Ni25Al15 bulk amorphous alloy — •Ahmed Shariq, Talaat Al-Kassab, and Reiner Kirchheim — Institut fuer Materialphysik, Uni- Goettingen, Tammanstr.1,D- 37077, Goettingen, Germany

Bulk amorphous alloys are advanced engineering materials owing to their excellent static and dynamic mechanical properties, wear properties, low coefficient of friction, magnetic properties and corrosion properties. The new amorphous alloys have much wider supercooled liquid region defined as the difference between crystallisation and glass transition temperatures which may extend up to 100K for some alloys. This wider range allows to explore the kinetics and thermodynamics in this region. The alloys with stabilized supercooled liquid state have three features in their alloy components i.e., multicomponent system, significant atomic size ratios above 12 percent and negative heat of mixing. Molecular-Dynamics (MD) simulations for a model Zr60Ni25Al15 ternary amorphous alloy already had shown two types of chemical short range ordering of Al and Ni sub systems. The 3D-tomographic atom probe (TAP) is proved to be currently the best experimental tool to gain experimental information on chemical heterogeneities at the atomic scale. The data from TAP has been used to elucidate the atomic distances among neighbouring atoms. The chemical short range ordering in the supercooled liquid region will be discussed on the basis of TAP results.