Effect of cyclic ageing on the early-stage clustering in Al–Zn–Mg(-Cu) alloys

• DOI: 10.1016/j.msea.2022.143280
• Publication Date: 2022-05-13T06:57:48Z
• Authors: Sohail Shah; Elisabeth Thronsen; Constantinos Hatz...; Sigurd Wenner; Calin D. Marioara; Randi Holmestad; Bjørn Holmedal
• Keywords: Atom probe; Number density

The cyclic application of mechanical stress to aluminum alloys at room temperature, referred as ageing, continuously injects vacancies, enabling dynamic precipitation a fine distribution solute clusters. These are uniformly distributed throughout the bulk and responsible for enhancing properties comparable values T6 conditions obtained by conventional artificial aging. atomic structure clusters in two Al–Zn–Mg (-Cu) is studied using atomically resolved transmission electron microscopy, their size, volume density chemistry investigated atom probe tomography. It was found that ageing yields high number exhibiting structural similarities GPI zones commonly observed after low temperature such alloys. A subsequent 10-day natural allows both cluster nucleation further growth, without altering structure. As compared strengthening caused accelerated during due precipitation. copper containing alloy also had higher amounts Mg Zn. Still, slightly lower smaller with Zn/Mg ratio formed this alloy, aging strength attributed contribution from each cluster.