Anelastic deformation processes in metallic glasses and activation energy spectrum model

Abstract

The isothermal kinetics of anelastic deformation below the glass transition temperature (so-called ‘stress induced ordering’ or ‘creep recovery’ deformation) was investigated in Ni-Si-B metallic glass. The relaxation time spectrum model and two recently developed methods for its calculation from the isothermal experimental data sets seem to be powerful tool for the study of anelastic deformation processes in disordered systems. Reliability of the used calculation methods (the first is based on the Fourier transformation technique and the second on the non-linear regression) is expressed in the fact that both provide qualitatively the same result (without prior assumptions concerning the form or nature of the spectrum): creep recovery relaxation spectrum consists of three relatively separated peaks with the well defined characteristic relaxation times. The influence of (i) loading time, (ii) the structural relaxation and (iii) unloading temperature on the spectrum is demonstrated and discussed. Using the assumption that different peaks in creep recovery spectra represent different type of elementary deformation processes (or different type of deformation defects) detected during the creep recovery, discussion concerning the eventual deformation defects will be actualized.