In-situ weak-beam scanning transmission electron microscopy for quantitative dislocation analysis in nuclear materials during post-irradiation annealing

Yoshida, Kenta*; Du, Y.*; Shimada, Yusuke*; Suzudo, Tomoaki   ; Toyama, Takeshi*; Inoue, Koji*; Arakawa, Kazuto*; Milan, K. J.*; Gerard, R.*; Nagai, Yasuyoshi*

We developed a weak-beam scanning transmission electron microscopy (WB-STEM) by installing a novel beam selector, annular detector, a high-speed CCD camera and imaging filter in a camera chamber of an aberration corrected electron microscope. In-situ observation confirmed that the newly-developed WB-STEM has improved the ability to observe the dynamic behavior of dislocation loops. In addition, we performed a numerical simulation of dislocation loop behavior using molecular dynamics, and confirmed that the experimental results were well explained by the theoretical analysis. Therefore, this WB-STEM is expected to be useful for understanding the embrittlement mechanism of nuclear materials such as reactor pressure vessel (RPV) steels.