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Influence de la prédéformation et des traitements thermiques sur la microstructure et les propriétés mécaniques des alliages Al-Zn-Mg-Cu

Abstract : We have studied the influence of thermomecanical treatments of Al-Zn-Mg-Cu alloys on their microstructure and mechanical properties.
More specifically, we have studied how the precipitation and hardening mechanisms are modified when dislocations are introduced prior to the ageing treatment.
The first approach to this problem is experimental. The objective was to obtain relationships between the microstructures developed during the various thermomechanical treatments and the resulting mechanical properties. For this purpose we have used a number of complementary investigation techniques: optical and electron microscopy, differential calorimetry, small angle X-ray scattering, atom probe tomography, microhardness and tensile tests.
The second approach was to develop a model for competitive precipitation between homogeneous precipitation and heterogeneous precipitation on dislocations. This model integrates continuously the different stages of precipitation (nucleation, growth and coarsening) and of precipitation hardening (shearing and by-passing). We have been able to reproduce most experimental results with this model.
Finally, we have studied the plasticity of our materials, as a function of the state of precipitation. More specifically, we have evidenced the presence of dynamic precipitation during tensile testing in supersaturated states, which induces a very high strain hardening.
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Contributor : Alexis Deschamps <>
Submitted on : Wednesday, March 25, 2009 - 11:26:03 AM
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Alexis Deschamps. Influence de la prédéformation et des traitements thermiques sur la microstructure et les propriétés mécaniques des alliages Al-Zn-Mg-Cu. Matériaux. Institut National Polytechnique de Grenoble - INPG, 1997. Français. ⟨tel-00370760⟩

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