The evolution of precipitates in an Al–Zn–Mg alloy

• DOI: 10.1016/j.jmrt.2023.02.144
• Publication Date: 2023-03-01T01:56:38Z
• Authors: E. Thronsen; S. Shah; C. Hatzoglou; C.D. Marioara; S. Wenner; S.J. Andersen; B. Holmedal; R. Holmestad
• Keywords: Atom probe

The precipitation sequence in Al–Zn–Mg alloys has been subject to many revisions over the years as more structural details of early-stage Guinier-Preston (GP) zones and precipitates have uncovered. To further investigate this, a 7003 aluminium alloy naturally aged for one year was subjected artificial ageing at 140 °C evolution precipitates. Scanning transmission electron microscopy coupled with atom probe tomography hardness measurements characterise precipitate structure chemistry different stages heat treatment. condition contained dense population GPI zones, co-existing smaller distribution η′ After 10 min, decreased from 121 HV 88 HV. number densities clusters were similar two conditions, while average size had increased during first min ageing. Zn/Mg ratio 2.0 1.7 no longer exhibited zone atomic structure, indicating that dissolved. Concurrently, fraction having 2% 18%. During ageing, again, reaching peak after 5 h. In this condition, dominant phase, η1, η2 T′ phases. Atomically resolved scanning images addition precession diffraction patterns disputed phase are presented compared literature.