Evolution of long-period stacking order (LPSO) in Mg97Zn1Gd2 cast alloys viewed by HAADF-STEM multi-scale electron tomography

Kazuhisa Sato, Shunya Tashiro, Shuhei Matsunaga, Yohei Yamaguchi, Takanori Kiguchi, Toyohiko J. Konno

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


We have studied three-dimensional (3D) structures and growth processes of 14H-type long-period stacking order (LPSO) formed in Mg97Zn1Gd2 cast alloys by single tilt-axis electron tomography (ET) using high-angle annular dark-field scanning transmission electron microscopy. Evolution of the solute-enriched stacking faults (SFs) and the 14H LPSO by ageing were visualised in 3D with a high spatial resolution in multi-scale fields of views from a few nanometres to ~10 μm. Lateral growth of the solute-enriched SFs and the LPSO in the (0 0 0 1)Mg plane is notable compared to the out-of-plane growth in the [0 0 0 1]Mg direction. The 14H LPSO grows at the cost of decomposition of the (Mg, Zn)3Gd-type precipitates, and accompany a change of in-plane edge angles from 30 to 60°. We have updated the Time–Temperature–Transformation diagram for precipitation in Mg97Zn1Gd2 alloys: starting temperatures of both solute-enriched SFs and LPSO formation shifted to a shorter time side than those in the previous diagram.

Original languageEnglish
Pages (from-to)1945-1960
Number of pages16
JournalPhilosophical Magazine
Issue number21
Publication statusPublished - 2018 Jul 23


  • Long-period stacking order (LPSO)
  • electron tomography
  • lateral morphology
  • magnesium alloys
  • scanning transmission electron microscopy (STEM)

ASJC Scopus subject areas

  • Condensed Matter Physics


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