Effect of Focal Depth of HAADF-STEM Imaging on the Solute Enriched Layers in Mg Alloys

• Kiguchi Takanori

  Institute for Materials Research, Tohoku University

• Yamaguchi Yohei

  Department of Materials Science, Graduate School of Engineering, Tohoku University

• Tashiro Shunya

  Department of Materials Science, Graduate School of Engineering, Tohoku University

• Sato Kazuhisa

  Institute for Materials Research, Tohoku University

• Konno Toyohiko J.

  Institute for Materials Research, Tohoku University

抄録

This study has found that the Z-contrast of aberration-corrected high-angle annular dark field-scanning transmission electron microscopy (HAADF-STEM) images of solute enriched layers in Mg-TM-RE (TM:Zn, RE:Y, Gd) alloys is sensitive to the imaging conditions: the defocus and the focal depth. Consequently, the depth position of solute enriched layers in the projected direction shows strong effect on the Z-contrast around each layer. The blurring of the Z-contrast is preferentially observed in both sides region along (0001)_Mg basal planes. The boundary position between HCP- and FCC-type stacking sequence at edge regions does not change by defocus. The permissible defocus amount is comparable to the focal depth. The aberration-corrected HAADF-STEM has short focal depth less than 10 nm, so that it is critical for interpreting image contrast that the thin foil thickness and the depth position of the nano-size structure such as the solute enriched layers. In turn, it can be presumed, by the blurring of the Z-contrast, that the depth position of the solute enriched layers in the projected direction. Thus, the focal depth of aberration-corrected HAADF-STEM is quite sensitive to the depth position of solute enriched layers in the thin foil of specimens and the defocus of the electron probe, so that the imaging condition of aberration-corrected HAADF-STEM is critical in order to interpret correctly the Z-contrast of the images.

収録刊行物

• MATERIALS TRANSACTIONS

  MATERIALS TRANSACTIONS 56 (10), 1633-1638, 2015

  公益社団法人 日本金属学会

キーワード

• magnesium alloy
• long-period stacking ordered structure (LPSO)
• solute enriched layers
• high-angle annular dark field-scanning transmission electron microscopy (HAADF-STEM)
• focal depth
• defocus
• channeling

詳細情報

• CRID: 1390001204253386112
• NII論文ID: 130005099178
• NII書誌ID: AA1151294X
• DOI: 10.2320/matertrans.maw201505
• ISSN: 13475320
• ISSN: 13459678
• NDL書誌ID: 026767114
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I026767114
• Web Site: https://www.jstage.jst.go.jp/article/matertrans/56/10/56_MAW201505/_pdf
• 本文言語コード: en
• データソース種別:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
  • KAKEN
• 抄録ライセンスフラグ: 使用不可