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Strain rate sensitivity of germanium-selenium glasses
Gwénolé Trenvouez  1@  , Cédric Bernard  2@  , Mariette Nivard  1@  , Vincent Keryvin  3@  , Jean-Pierre Guin  4@  
1 : Institut de Physique de Rennes  (IPR)  -  Website
Universite de Rennes 1, Centre National de la Recherche Scientifique : UMR6251
Bâtiment 11A , B, C, E – 10B263 av. Général Leclerc35042 Rennes cedex FRANCE -  France
2 : Laboratoire d'Ingénierie des Matériaux de Bretagne  (LIMATB)
Université de Bretagne Sud
3 : Laboratoire d'Ingénierie des Matériaux de Bretagne  (LIMATB)  -  Website
Université de Bretagne Sud : EA4250
Rue Saint Maudé -56321 Lorient Cedex -  France
4 : Institut de Physique de Rennes  (IPR)
Institut de Physique de Rennes

Chalcogenide glasses are widely used in optical applications either as information carrier or as
sensors due to their optical transparency in the mid-infrared window (8-15 μm), high refractive index and non linearity. Glasses from the GexSe1-x system have been extensively studied over the last decades because some of their physical properties do show an anomalous behaviour (Tg, density, band gap, indentation fracture
toughness) at certain specific compositions for instance at x=20% also called the percolation
threshold. In this work we studied the indentation behaviour of GexSe(1-x) (0≤x≤30) under
constant strain rate conditions. Instrumented Berkovich micro indentation were performed at
different strain rates (from 10 -3 to 10 -1 s -1 ) at ambiante temperature, indentation residual imprints
were image by atomic force microscopy. Energies at stake during indentation, strain rate sensitivity
(computed from Norton's law) as well as indentation imprints shape and volumes are discussed as a
function of the litterature and glass structure. Experimental results are in good agreement with a
similar study based on pure Se glass. From AFM pictures a transition behaviour is identified near
the percolation threshold.


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