Advanced microscopy techniques for investigation of the precipitation in pre-strained Al-Cu-Mg alloy (AA2024) - Archive ouverte HAL Accéder directement au contenu
Poster De Conférence Année : 2023

Advanced microscopy techniques for investigation of the precipitation in pre-strained Al-Cu-Mg alloy (AA2024)

Mohamed Sennour
Lisa T. Belkacemi
  • Fonction : Auteur
  • PersonId : 1125727
Vladimir A. Esin

Résumé

Age-hardenable Al–Cu–Mg alloys are widely used for various applications due to their properties, such as low density to strength ratio and increased corrosion resistance. The commercial 2024 aluminium alloy (AA2024) is one of the most used alloys in aircraft manufacturing with a quite simple precipitation sequence including co-clusters and Guinier-Preston-Baragyatski (GPB) zones formed during natural ageing and precipitation of the equilibrium S-phase (Al2CuMg) during artificial ageing. This study aims to investigate the impact of pre-straining, performed by cold rolling, on precipitation of the S-phase in AA2024. First, the deformation microstructure, mainly the arrangement of dislocation substructures, was analysed using electron backscatter diffraction (EBSD) in scanning electron microscope (SEM). Atom probe tomography (APT) and differential scanning calorimetry (DSC) were further used to characterize co-clusters in naturally aged AA2024-T3 after subsequent cold rolling, showing that they are destroyed during pre-straining and not reconstituted during following natural ageing. Evolution of S-phase precipitates during artificial ageing of cold-rolled (CR) samples was investigated by transmission electron microscopy (TEM) modes. Hence, despite initial dominant heterogeneous nucleation due to dislocations induced by the cold rolling, the precipitates of S-phase were distributed homogeneously at peak hardness. To explain this result, in situ heating was performed in TEM and mechanisms of nucleation and growth of S-phase precipitates in cold-rolled samples were investigated. The size distribution of S-phase precipitates was investigated using dark-field imaging. A refinement of precipitates was observed due to cold rolling with changes in the aspect ratio. Refinement and homogeneous distribution of S-phase precipitates in cold rolled samples after further artificial ageing were confirmed as well by electron tomography. The study demonstrates the valuable contribution of combined advanced microscopy techniques to understand microstructural changes and precipitation behaviour in aluminium alloys and therefore contribute to the development of novel production processes.

Domaines

Matériaux
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Dates et versions

hal-04354413 , version 1 (19-12-2023)

Identifiants

  • HAL Id : hal-04354413 , version 1

Citer

Daniel Irmer, Mohamed Sennour, Lisa T. Belkacemi, F. Sun, Charbel Moussa, et al.. Advanced microscopy techniques for investigation of the precipitation in pre-strained Al-Cu-Mg alloy (AA2024). IMC20 - 20th International Microscopy Congress, Sep 2023, Busan, South Korea. ⟨hal-04354413⟩
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