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Mantle region accommodating two-dimensional grain boundary sliding in ODS ferritic steel |
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| Authors: | Hiroshi Masuda Hirobumi Tobe Eiichi Sato Yoshito Sugino Shigeharu Ukai |
| Affiliation: | 1. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo, Sagamihara, Kanagawa 252-5210, Japan;2. Kobelco Research Institute, Inc., 2-3-1 Shinhama, Arai, Hyogo 676-8670, Japan;3. Division of Materials Science and Engineering, Hokkaido University, 2 Kita 13, Nishi 8, Kita, Hokkaido, Sapporo, 060-8628, Japan |
| Abstract: | Two-dimensional grain-boundary sliding (GBS) was achieved microscopically in an oxide-dispersion-strengthened ferritic steel with an elongated and aligned grain structure, which was deformed perpendicular to the long axis. At the border between superplastic regions II and III, microscopic deformation was observed using sub-micron grids drawn on the material surface using a focused ion beam. GBS was accommodated by intragranular deformations in narrow areas around grain boundaries, which has been predicted by earlier researchers as characteristics of the core–mantle model. These observations suggest that dislocations slip only in the mantle regions around wavy boundaries to relax the stress concentration caused by GBS during superplasticity. |
| Keywords: | superplasticity grain boundary sliding dislocations oxide-dispersion-strengthened (ODS) steel focused ion beam (FIB) core–mantle model |