Modélisation des processus de précipitation et prédiction des propriétés mécaniques résultantes dans les alliages d’aluminium à durcissement structural : Application au soudage par Friction Malaxage (FSW) de tôles AA2024

Abstract : In the aeronautic industry, the friction stir welding (FSW) process is seen as an interesting option to lighten aircraft structure by replacing the standard riveting technology used to join parts. Numerical simulation is chosen to improve understanding of the different mechanisms occurring during FSW. The aluminum alloy studied is an AA2024-T3 grade. Its mechanical properties mainly derive from structural hardening mechanisms. An accurate model of precipitate evolution is essential to define hardness profile of the weld. The chosen simulation has to be robust and time-efficient in order to be suitable for the FSW process modeling. It must consider the two families of precipitates (GPB zones and S phase) and model nucleation, growth and coarsening phenomena. A PSD model is chosen and coupled with thermodynamic equilibrium calculations. To define the growth kinetics of precipitates, an exact analytical solution is extended to a multi-component alloy. Knowing the distribution of precipitates size, the mechanical properties are defined based on an empirical model. The amount and properties of phases are initialized through non-isothermal DSC calibration and comparison between experimental heat flux and simulated one. Isothermal test is selected to establish the link between precipitation state and mechanical properties. The model is applied to the simulation of microstructural evolution in FSW in order to predict the final properties of the weld. Thermal changes are determined through the use of a macroscopic model developed during a twin project within the Chair Daher. Numerical results are compared with instrumented experiments and show a good estimate of hardness. The experimental profiles are found, as well as the characteristics of the different areas. This validates the approach and its efficiency to simulate the evolution of the precipitation process.
Document type :
Theses
Complete list of metadatas

Cited literature [1 references]  Display  Hide  Download

https://pastel.archives-ouvertes.fr/tel-01565304
Contributor : Abes Star <>
Submitted on : Wednesday, July 19, 2017 - 5:16:05 PM
Last modification on : Monday, November 12, 2018 - 10:53:51 AM

File

2015ENMP0090_archivage.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-01565304, version 1

Citation

Valentine Legrand. Modélisation des processus de précipitation et prédiction des propriétés mécaniques résultantes dans les alliages d’aluminium à durcissement structural : Application au soudage par Friction Malaxage (FSW) de tôles AA2024. Matériaux. Ecole Nationale Supérieure des Mines de Paris, 2015. Français. ⟨NNT : 2015ENMP0090⟩. ⟨tel-01565304⟩

Share

Metrics

Record views

1268

Files downloads

393