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Analyse et modélisation micromécanique du comportement et de la rupture fragile de l'acier 16MND5: prise en compte des hétérogénéités microstructurales

Abstract : Reactor Pressure Vessel is the second containment barrier between nuclear fuel and the environment. Electricit'e de France's reactors are made with french 16MND5 low-alloyed steel (equ. ASTM A508 Cl.3). Various experimental techniques (scanning electron microscopy, X-ray diffraction ...) are set up in order to characterize mechanical heterogeneities inside material microstructure during tensile testing at different low temperatures [-150°C;-60°C]. Heterogeneities can be seen as the effect of both "polycritalline" and "composite" microstructural features. Interphase (until 150 MPa in average between ferritic and bainitic macroscopic stress state) and intraphase (until 100 MPa in average between ferritic orientations) stress variations are highlighted. Modelling involves micromechanical description of plastic glide, mean fields models and realistic three-dimensional aggregates, all put together inside a multiscale approach. Calibration is done on macroscopic stress-strain curves at different low temperatures, and modelling reproduces experimental stress heterogeneities. This modelling allows to apply a local micromechanical fracture criterion for crystallographic cleavage. Deterministic computations of time to fracture for different carbides random selection provide a way to express probability of fracture for the elementary volume. Results are in good agreement with hypothesis made by local approach to fracture. Hence, the main difference is that no dependence to loading nor microstructure features is supposed for probability of fracture on the representative volume: this dependence is naturally introduced by modelling.
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https://pastel.archives-ouvertes.fr/pastel-00002143
Contributor : Ecole Arts Et Métiers Paristech <>
Submitted on : Tuesday, February 20, 2007 - 8:00:00 AM
Last modification on : Monday, April 16, 2018 - 10:42:05 AM
Long-term archiving on: : Thursday, September 30, 2010 - 7:41:19 PM

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  • HAL Id : pastel-00002143, version 1

Citation

Jean-Philippe Mathieu. Analyse et modélisation micromécanique du comportement et de la rupture fragile de l'acier 16MND5: prise en compte des hétérogénéités microstructurales. Sciences de l'ingénieur [physics]. Arts et Métiers ParisTech, 2006. Français. ⟨NNT : 2006ENAM0037⟩. ⟨pastel-00002143⟩

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