http://dspace.univ-setif.dz:8888/jspui/handle/123456789/274 2026-07-09T01:10:11Z http://dspace.univ-setif.dz:8888/jspui/handle/123456789/275 Titre: Comportement thermomécanique des céramiques étudié par spectroscopie mécanique Auteur(s): Schaller, Robert Résumé: High temperature plastic or even superplastic deformation of fine-grained ceramics is usually interpreted as due to grain boundary sliding. As grain boundary sliding dissipates energy, mechanical spectroscopy is well suited to study such a mechanism. In fine-grained tetragonal zirconia, the mechanical loss exhibits an exponential increase athigh temperature, which accounts for creep appearance in the material. In silicon nitride, a mechanical loss peak related to dissipation in the glassy phase pockets has been observed. This peak disappears after annealing leading to the recrystallization of the amorphous pockets, leadingto a better creep resistance. Silicon nitride sintered under gas pressure contains a very small amount of glassy phase and consequently exhibits a very small mechanical loss peak and consequently a strong resistance to deformation until 1450°C. 2011-01-01T00:00:00Z