Anelastic and Viscoelastic Behaviour of Amorphous Zr₆₅Cu_17.5Ni₁₀Al_7.5 in the Range of the Glass Transition

Abstract
Reversible (anelasticity) and the irreversible (viscosity) relaxations in the amorphous alloy Zr₆₅Cu_17.5Ni₁₀Al_7.5 have been investigated by means of creep and mechanic after-effect measurements of the shear strain, which were performed in an inverted torsion pendulum. For the evaluation of the measurements a new relaxation model is proposed which takes into account that in the range of the glass-transition temperature T_g the local atomic arrangement is steadely changing. By introducing a finite mean life time τ of local structure units we are able to trace the origin of the anelasticity and the viscosity to the same atomic relaxation processes. The temperature dependence of the viscosity η measured between 560 K and 668 K shows a jump in the activation energy at T_g = 606 K from 2.1 eV below T_g to 5.6 eV above T_g.