NEW INSIGHTS OF THE SOLID-STATE TRANSFORMATIONS IN THE AG-SE-GE SYSTEM - A MECHANICAL SPECTROSCOPY STUDY

a study of degrees of freedom exhibited by partially crystallised mate rial of the system Ag-Se-Ge is reported. Mechanical spectroscopy revea ls 3 processes in the temperature range 250K to 330K. Two processes at 298K and 315K are assigned to solid state transformations in Ag8GeSe6 crystallites. A broad relaxation process exhibiting a high activation energy is connected to cooperative events assumed to occur in the gla ssy matrix. The two first processes also manifest in DSC experiments. The high temperature one is definitively attributed Lo allotropic tran sformation of Ag(8)CcSe(6) crystalline phase. The low temperature one is reported for the first Lime in this paper and is attributed to the transformation of a crystalline metastable phase induced by constraint s imposed by tile surrounding glassy matrix.