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Étude de l'effet de taille et de structure sur l'élasticité de composites W/Cu nanostructurés en couche mince

Abstract : The mechanical behavior of crystalline material has a high dependence on its microstructure, notably when crystallite size reaches the nanometer scale. Crystallites size is controled by the stratification of thermodynamically immiscible materials, namely tungsten and copper, isotropic and anisotropic elastically, respectively. Thin films were deposited by physical vapor deposition and their characterizations were carried out combining electron microscopy and X-ray diffraction and diffusion. In situ tensile testing combined with X-ray diffraction on supported composite W/Cu have been used to get insight into sample mechanical behavior. This work emphasises the strong complementarity between electron microscopy and X-ray diffraction analyses on microstructure characterizations, required to interpret and model tensile testing results. Theses analysis have revealed that very thin copper layers arrange as dispersoïds and that a particular crystallographic orientation distribution within tungsten layers appear as <110> and <111>. The results obtained on quasi-isotropic copper dispersoïds and laminated W/Cu composites have clearly revealed structure and size effects in tungsten sub-layers. A more detailed study of the elastic domain of laminated composite has not only revealed a strong dependence on residual stresses, but also an uppermost dislocation appearance within copper layers leading to a load transfer on tungsten layers, leading to mode II crack apparitions.
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Contributor : Baptiste Girault <>
Submitted on : Wednesday, February 17, 2010 - 11:26:04 AM
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Baptiste Girault. Étude de l'effet de taille et de structure sur l'élasticité de composites W/Cu nanostructurés en couche mince. Matière Condensée [cond-mat]. Université de Poitiers, 2008. Français. ⟨tel-00457334⟩

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