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Modélisation du procédé de fluotournage du tantale et du traitement thermique associé

Abstract : We first propose for the tantalum a physical constitutive law depending on the dislocations density that is able to take in account the effects of temperature and the effects of strain rate on a broad range from 10-4 to 103 s-1. Combined with the rheological model, we present a relationship between dislocation density and Vickers microhardness. The parameters of this relationship are identified for the tantalum by numerical modeling of the indentation. The modeling of flow-forming process is done by the commercial software Forge2007 ®. Tests on lead and copper are used to compare the numerical simulation to the experiment results. An ALE formulation, based on an existing formulation, is developed to optimize the refinement of the mesh in contact with tools. We developed special algorithms to properly maintain the free surfaces despite the movements of the mesh relatively to the material in the flow-forming process. Finally, we propose a relationship that models the evolution of dislocation density during a recovery heat treatment. In situ observations of the tantalum microstructure during heat treatment helped to understand the kinetics of recrystallization as well as the mechanisms of germination. Finally, we present a method for measuring the recrystallized volume fraction by measuring the microhardness.
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https://pastel.archives-ouvertes.fr/tel-00443562
Contributor : Magalie Prudon <>
Submitted on : Wednesday, December 30, 2009 - 2:56:36 PM
Last modification on : Thursday, September 24, 2020 - 5:22:54 PM
Long-term archiving on: : Friday, June 18, 2010 - 12:10:59 AM

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  • HAL Id : tel-00443562, version 1

Citation

Marie Houillon. Modélisation du procédé de fluotournage du tantale et du traitement thermique associé. Mécanique [physics.med-ph]. École Nationale Supérieure des Mines de Paris, 2009. Français. ⟨NNT : 2009ENMP1650⟩. ⟨tel-00443562⟩

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