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Higa, Ryota*; Fujihara, Hiro*; Toda, Hiroyuki*; Kobayashi, Masakazu*; Ebihara, Kenichi; Takeuchi, Akihisa*
Keikinzoku, 73(11), p.530 - 536, 2023/11
In Al-Zn-Mg alloys, suppression of hydrogen embrittlement is necessary to improve their strength. In this study, the distribution of stress, strain, and hydrogen concentration in the actual fracture region was investigated using the crystal plasticity finite element method and hydrogen diffusion analysis based on a model derived from three-dimensional polycrystalline microstructural data obtained by X-ray CT. In addition, the distributions of stress, strain, and hydrogen concentration were compared with the actual crack initiation behavior by combining in-situ observation of tensile tests using X-ray CT and simulation. The results show that stress loading perpendicular to the grain boundary due to crystal plasticity dominates grain boundary crack initiation. It was also found that internal hydrogen accumulation due to crystal plasticity has little effect on crack initiation.
Shibata, Toshio*; Haruna, Takumi*; Fujimoto, Shinji*; Zhang, S.*
JAERI-Tech 2000-061, 38 Pages, 2000/09
JAERI-Tech-2000-061.pdf:10.98MB
no abstracts in English
; *; ; ; *
Eng.Fract.Mech., 28(3), p.345 - 360, 1987/03
no abstracts in English
Kondo, Keietsu; Aoki, So; Fujimura, Yuki; Kaji, Yoshiyuki
no journal, ,
The effect of the long-term thermal aging (LTA) on the SCC susceptibility to initiation in cold worked L-grade austenitic stainless steels has been investigated. The thermal aging treatments at 288
C for more than 14,000h were conducted on Type 316L SS samples after cold rolling with 20% thickness reduction, and CBB testing was performed to both aged and unaged samples. The results showed that an obvious increase of IGSCC susceptibility was induced after the LTA treatment. In order to reveal the enhancement factor of the SCC susceptibility in LTA treated specimens microstructural examination was conducted by means of SEM/EBSD and TEM. Those results suggested that movement and rearrangement of dislocations toward the dislocation cell structure occurred during LTA treatment. It is presumed that the dislocation cell structure formed during the LTA process might cause the homogeneous plastic deformation and the localization of stress/strain, and consequently, enhance the SCC susceptibility to initiation.
