Indications for a slow β-relaxation in a fragile metallic glass

The elastic modulus of the fragile metallic glass Pd77Cu6Si17 is investigated by mechanical spectroscopy at I Hz. In the vicinity of the glass-transition, a Havriliak-Negami fitting function in temperature domain is used to model the a-relaxation. The measured data clearly deviate from the model as has also been reported earlier for the strong metallic glass Zr65Al7.5Cu27.5. A secondary relaxation has to be taken into account to achieve a suitable fit. Our experimental results provide evidence that a slow beta-relaxation, existing in both strong and fragile amorphous metals, can be regarded as a universal property of glasses. (c) 2006 Elsevier B.V. All rights reserved.