Abstract
Partially ordered Ni4Mo alloys were observed for the first time at an atomic resolution with high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM). The Mo atomic columns in the D1a ordered structure were clearly visualized as bright square dots in the HAADF-STEM image. It was found that the ordered regions were observed with a high contrast in the defocus condition a little overfocused from the Scherzer defocus (Δf = √CS · γ) which is the condition for the smallest electron probe in STEM. The phenomenon was interpreted successfully by using the approximate imaging theory for HAADF-STEM proposed by Jesson et al. Using the present experimental and simulation results, an approximate imaging theory for visualizing short range ordered state in binary alloys, such as the Ni4Mo alloys, is proposed.
Original language | English |
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Pages (from-to) | 414-418 |
Number of pages | 5 |
Journal | Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals |
Volume | 65 |
Issue number | 5 |
DOIs | |
Publication status | Published - Jan 1 2001 |
Externally published | Yes |
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Mechanics of Materials
- Metals and Alloys
- Materials Chemistry