Eleventh International Conference on Internal Friction and Ultrasonic Attenuation in Solids
J. Phys. IV France 06 (1996) C8-655-C8-658
New Insights of the Solid State Transformations in the Ag-Se-Ge System : a Mechanical Spectroscopy StudyS. Etienne1, G. Taillades2, A. Pradel2 and M. Ribes2
1 LMPSM, UA 155 du CNRS, Ecole des Mines, Parc de Saurupt, 54042 Nancy cedex, France
2 LPMC, UMR 5617 du CNRS, Université Montpellier II, Place E. Bataillon, 34000 Montpellier cedex, France
a study of degrees of freedom exhibited by partially crystallised material of the system Ag-Se-Ge is reported. Mechanical spectroscopy reveals 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 glassy matrix. The two first processes also manifest in DSC experiments. The high temperature one is definitively attributed to allotropic transformation of Ag8GeSe6 crystalline phase. The low temperature one is reported for the first time in this paper and is attributed to the transformation of a crystalline metastable phase induced by constraints imposed by the surronding glassy matrix.
© EDP Sciences 1996