Volume 9, Issue 2 (February 2012)
Stability of Metallic Glasses: Criteria and Prediction of Ductile-Brittle Transition and Crystallization
A close correlation between the mechanical behavior changes of metal-metalloid glasses and their relaxation spectrum heat emissions has been found. The criteria of crystallization and ductile-brittle transition for these kinds of metallic glasses (MGs) have been established. They correspond to the heat emission balance between the low- and high-temperature parts of the relaxation spectrum. The model of MGs as a system constituting an additive sum of elementary two-level transitions with continuously distributed activation energies is proposed for the analytical description of the relaxation spectrum and its parameters. The methods developed in the approximation of the model permit the determination of the current state of MG materials at an arbitrary temperature, as well as forecasting of their ductile-brittle transition and crystallization according to heat emission alterations of the relaxation spectrum.