Weak-beam scanning transmission electron microscopy for quantitative dislocation density measurement in steels. (18th January 2017)

• Record Type: Journal Article
• Authors: Yoshida, Kenta; Shimodaira, Masaki; Toyama, Takeshi; Shimizu, Yasuo; Inoue, Koji; Yoshiie, Toshimasa; Milan, Konstantinovic J.; Gerard, Robert; Nagai, Yasuyoshi
• Is Part Of: Microscopy. Volume 66:Number 2(2017)
• Page Start: 120
• Page End: 130
• Publication Date: 2017-01-18
• Subjects: STEM -- diffraction contrast -- weak-beam -- irradiation damage -- dislocation; Microscopy -- Periodicals; 502.825
• DOI: 10.1093/jmicro/dfw111
• Languages: English
• ISSNs: 2050-5698

Abstract

Abstract: To evaluate dislocations induced by neutron irradiation, we developed a weak-beam scanning transmission electron microscopy (WB-STEM) system by installing a novel beam selector, an annular detector, a high-speed CCD camera and an imaging filter in the camera chamber of a spherical aberration-corrected transmission electron microscope. The capabilities of the WB-STEM with respect to wide-view imaging, real-time diffraction monitoring and multi-contrast imaging are demonstrated using typical reactor pressure vessel steel that had been used in an European nuclear reactor for 30 years as a surveillance test piece with a fluence of 1.09 × 10 20 neutrons cm – 2 . The quantitatively measured size distribution (average loop size = 3.6 ± 2.1 nm), number density of the dislocation loops (3.6 × 10 22 m −3 ) and dislocation density (7.8 × 10 13 m m – 3 ) were carefully compared with the values obtained via conventional weak-beam transmission electron microscopy studies. In addition, cluster analysis using atom probe tomography (APT) further demonstrated the potential of the WB-STEM for correlative electron tomography/APT experiments.