Dresden 2006 – wissenschaftliches Programm

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DF: Dielektrische Festkörper

DF 6: Glass II (together with division ‘Dynamics and Statistical Physics’ [DY])

DF 6.1: Vortrag

Dienstag, 28. März 2006, 14:30–14:50, M{\"U}L Elch

Indications for a slow β-relaxation by mechanical spectroscopy of a strong and a fragile metallic glass — •Jörg Hachenberg, Annelen Kahl, and Konrad Samwer — 1. Physikalisches Institut, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany

Mechanical spectroscopy is used to investigate the elastic properties of the strong metallic glass former Zr₆₅Al_7.5Cu_27.5 and the fragile Pd₇₇Cu₆Si₁₇. The dynamic mechanical analyser is used to measure the complex elastic modulus of melt spun bands in the low Hz regime while the double-paddle oscillator is applied for thin films at 5.4 kHz. In the vicinity of glass-transition, the α-relaxation is fitted using a Havriliak-Negami function in temperature domain. The measured data clearly deviate from the model for both metallic glasses. An explicit misfit on the low temperature flank, also termed excess wing, is interpreted as an underlying, merged slow β-relaxation. Our experimental results provide evidence that this secondary relaxation, existing in both strong and fragile amorphous metals, can be regarded as a universal property of glasses and is compared with recent MD-simulations by H. Teichler et al.

This work is supported by the Deutsche Forschungsgemeinschaft, Graduiertenkolleg 782 and SFB 602, TP B8.