Viscosity of bulk and ribbon Zr-based glasses well below and in the vicinity ofTg:A comparative study

Autor: Jozef Miškuf, Kornel Csach, A. E. Berlev, O. P. Bobrov, V. A. Khonik, M.Yu. Yazvitsky, H. Neuhäuser, Alena Juríková
Rok vydání: 2003
Předmět:
Zdroj: Physical Review B. 68
ISSN: 1095-3795
0163-1829
DOI: 10.1103/physrevb.68.132203
Popis: Tensile creep tests of bulk and ribbon samples of ${\mathrm{Zr}}_{52.5}{\mathrm{Ti}}_{5}{\mathrm{Cu}}_{17.9}{\mathrm{Ni}}_{14.6}{\mathrm{Al}}_{10}$ metallic glass have been performed over a wide range of heating rates. It has been found that a change of the quenching rate at least by three orders of magnitude exerts little influence on the shear viscosity below the glass transition temperature ${T}_{g}.$ In all cases, the viscosity is strongly dependent on the heating rate, which can be explained as a result of irreversible structural relaxation with distributed activation energies. It is argued that the volume spectral density of relaxation centers in the high-energy part of the activation energy spectrum (AES) of irreversible structural relaxation is higher for ribbon samples than that for bulk specimens by about 30%, whereas the low-energy part of the AES remains unchanged. Above ${T}_{g},$ the viscosity of bulk samples is always lower than that of ribbons, which may be interpreted in terms of the phase decomposition.
Databáze: OpenAIRE