X-ray studies of dynamic aging in an aluminum alloy subjected to severe plastic deformation

• Spherical fcc β-Mg2Si precipitates formed in Al 6201 alloy during dynamic aging in the course of severe plastic deformation.
• The size, shape and distribution of the precipitates due to artificial and dynamic aging were revealed by SAXS method.
• Monoclinic needle-like β" precipitates and Al5FeSi intermetallic phase were detected in 6201 alloy after T6 treatment.

In this work, X-ray scattering methods were applied for a quantitative characterization of the microstructure of an aluminum alloy of the Al–Mg–Si system during dynamic aging realized through the high pressure torsion technique. A qualitative and quantitative phase analysis of the alloy was performed, together with Al alloy lattice parameter determination. From the reflections broadening the effective size of the coherent scattering domains and the lattice microstrain were determined in the framework of the Halder–Wagner approach. Using the method of small-angle X-ray scattering, the quantitative characteristics of the size, shape and spatial distribution of the secondary phase particles formed in the Al alloy during dynamic aging were established. In order to validate the obtained results, the method of small-angle X-ray scattering was preliminarily tested on similar samples after artificial aging and compared with the results from small-angle neutron diffraction widely known in literature.