Basic Concepts of the Free Volume Model: Structural Relaxation and Viscosity in the Framework of the Model
The basic concept and ideals of the free volume model (FVM) of Turnbull and Cohen are considered. The relation between structural relaxation and atomic free volume in amorphous condensed matter is pointed out. The viscosity temperature dependence of amorphous metallic alloys in the framework of the free volume model, as considered by F. Spaepen, A. van den Beukel, P. Duine, etc., is presented and discussed. The contribution of the authors to the extension of the FVM ideas for describing the viscosity temperature dependence of glassy metals under nonisothermal experimental conditions is presented. An experimental proof of the correctness of this FVM extension is given.