Formation of solute nanostructures in an Al–Zn–Mg alloy during long-term natural aging

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal

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Author(s)

  • Jizi Liu
  • Rong Hu
  • Jialing Zheng
  • Yidong Zhang
  • Zhigang Ding
  • Wei Liu
  • Gang Sha

Detail(s)

Original languageEnglish
Article number153572
Journal / PublicationJournal of Alloys and Compounds
Volume821
Online published27 Dec 2019
Publication statusPublished - 25 Apr 2020
Externally publishedYes

Abstract

Nature aging (NA) is believed to produce solute nanostructures, including solute clusters and GPI zones in Al–Zn–Mg alloys. Here we report the first observation that GPII (GPη’) zones with an average Zn/Mg ratio near 1.3–1.4 formed in the Al–Zn–Mg alloys during long-term natural aging. High-angle-annular-dark-field scanning transmission electron microscopy and atom probe tomography were used to study the evolution of solute nanostructures during natural aging. Early clusters were found to have a wide spread of Zn/Mg ratios and their number density increased sharply with a dramatic hardening effect during the first month ageing. Further ageing up to 3 months made the Zn/Mg ratios of the solute clusters gradually converge to near 1.2 (GPI zones), but produced no change in the morphology, size distribution and volume fraction of the solute nanostructures, as well as hardness. At room temperature, GPII (GPη’ type) zones formed very slowly and provided stronger hardening effects than early clusters. Importantly, unlike solute-rich clusters, GPI and GPη’ zones are easy to transform into η′ during subsequent artificial ageing, avoiding hardness drop at the early stage of subsequent artificial aging at 120 °C.

Research Area(s)

  • Aluminum alloys, APT, GPII zones, HAADF-STEM, Natural aging

Citation Format(s)

Formation of solute nanostructures in an Al–Zn–Mg alloy during long-term natural aging. / Liu, Jizi; Hu, Rong; Zheng, Jialing; Zhang, Yidong; Ding, Zhigang; Liu, Wei; Zhu, Yuntian; Sha, Gang.

In: Journal of Alloys and Compounds, Vol. 821, 153572, 25.04.2020.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal