ANELASTIC DEFORMATION PROCESSES IN METALLIC GLASSES AND ACTIVATION-ENERGY SPECTRUM MODEL

The isothermal kinetics of anelastic deformation below the glass trans ition temperature (so-called 'stress induced ordering' or 'creep recov ery' deformation) was investigated in Ni-Si-B metallic glass. The rela xation time spectrum model and two recently developed methods for its calculation from the isothermal experimental data sets seem to be powe rful tool for the study of anelastic deformation processes in disorder ed systems. Reliability of the used calculation methods (the first is based on the Fourier transformation technique and the second on the no n-linear regression) is expressed in the fact that both provide qualit atively the same result (without prior assumptions concerning the form or nature of the spectrum): creep recovery relaxation spectrum consis ts of three relatively separated peaks with the well defined character istic relaxation times. The influence of (i) loading time, (ii) the st ructural 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 defo rmation processes (or different type of deformation defects) detected during the creep recovery, discussion concerning the eventual deformat ion defects will be actualized. (C) 1997 Elsevier Science S.A.