Strain Relaxation and Internal Friction in the Range of the Glass Transition

Abstract

Abstract For the investigation of structural relaxation near the glass transition quasistatic creep after-effect measurements have been performed on the alloy Zr65Cu17:5Ni10Al7:5 which shows a large stability above the glass temperature T g. By a separation of anelastic local atomic rearrangements and viscous long-range diffusion processes the thermal activation parameters of both processes could be determined from Arrhenius diagrams. Below T g = 606 K an activation enthalpy of 2.1 eV and above T g an activation enthalpy of 5.6 eV has been determined. For a quantitative description of these relaxation phenomena a new dynamic model is developed which takes into account the continuous formation and annihilation of relaxation centers near T g. From measurements of the internal friction after rapid temperature changes it could be shown that extended relaxation centers present above T g become instable below T g and are split up by diffusion processes above 585 K, however, disappear spontaneously below 580 K.