In thermomechanical processes like friction extrusion (FE) and friction consolidation (FC), where both severe plastic deformation (SPD) and frictional heating contribute to phase evolution and precipitate behavior [1, 2], an understanding of precipitation kinetics during processing is crucial for altering the microstructure and properties of aluminium alloys. This study examines precipitation behaviour in Al alloy alloys at the high-energy material science beamline P07 at PETRA III (DESY, Hamburg) using a specialised in-situ setup, FlexiStir, adapted for FE and FC, in addition to Small-Angle X-ray Scattering (SAXS) and Wide-Angle X-ray Scattering (WAXS). Real-time tracking and in-depth study of the evolution of the precipitate size, distribution, and phase fraction throughout the thermo-mechanical process are made possible by the combined SAXS/WAXS approach. Furthermore, lattice expansion of aluminium measured from WAXS signals was used to predict process temperatures.

The study emphasises how temperature and deformation affect the evolution of precipitation. According to preliminary findings, SPD speeds up the kinetics of precipitation while increasing grain size. Nevertheless, as the temperature increases, the precipitate volume decreases. The mechanical characteristics of these alloys are greatly impacted by an increase in precipitate volume that is seen after cooling. The study is intended to improve the FE and FC procedures for high-performance aluminium alloys, expanding their use in aerospace and other sectors that demand excellent mechanical and thermal properties.

Acknowledgement: This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 101001567).

References

1. Su, Jian-Qing and Nelson, Tracy W and Sterling, Colin J. Friction stir processing of large-area bulk UFG aluminum alloys. Scripta materialia 52, 135–140 (2005).

2. Sabirov, Ilchat and Murashkin, M Yu and Valiev, RZ. Nanostructured aluminium alloys produced by severe plastic deformation: New horizons in development. Materials science and engineering: A 560, 1–24 (2013).

Elizabeth Mathew (M.Sc.)