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Déformation dans l'intervalle de transition vitreuse de verres métalliques

Abstract : Interest in the mechanical behaviour of metallic glasses, materials with no long-range order, has picked up recently due to the development of alloys that are “amorphisable” at low critical quenching rates. These new alloys are now able to be prepared as bulk specimens of mm to cm size. The possibility to elaborate bulk specimens of metallic glasses, as opposed to ribbons which were studied previously, means that true bulk mechanical properties can now be investigated. Of the different metallic glasses existing, it is the zirconium based alloys that has reached use in the industrial scale. The aim of this study is to characterise the homogeneous deformation of bulk zirconium-based metallic glasses in conditions around the glass transition temperature. The material was studied primarily using constant strain rate compression tests, and internal friction tests. Microstructural characterisation was done by DSC, X-Ray diffraction and neutron diffraction.In this work, an elasto-viscoplastic model that describes the deformation behaviour of bulk metallic glasses around the glass transition temperature is proposed. The model is based on the concept of free-volume, developed by Spaepen, coupled to a kinetic equation for the formation-annihilation of flow defects. Mechanical behaviour and microstructural evolution are well reproduced by the model. The model also explains the existence of a master curve for viscosity in temperature and strain rate, and reproduces the transients observed during deformation and seems to establish the cooperative nature of the elementary mechanisms, however it is unable to describe the internal friction tests.
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Contributor : Marc Bletry <>
Submitted on : Thursday, August 4, 2005 - 5:46:22 PM
Last modification on : Friday, November 6, 2020 - 4:38:59 AM
Long-term archiving on: : Friday, November 25, 2016 - 9:23:15 AM

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  • HAL Id : tel-00009893, version 2

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Marc Bletry. Déformation dans l'intervalle de transition vitreuse de verres métalliques. Matériaux. Institut National Polytechnique de Grenoble - INPG, 2004. Français. ⟨tel-00009893v2⟩

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