Numerical verification for the effect of suppressing hydrogen embrittlement by Sn doping in the Al-Zn-Mg alloy

Ebihara, Kenichi; Fujihara, Hiro*; Shimizu, Kazuyuki*; Yamaguchi, Masatake; Toda, Hiroyuki*

International Journal of Hydrogen Energy, 136, p.751 - 756, 2025/06

https://doi.org/10.1016/j.ijhydene.2024.05.146

It has been experimentally reported that adding tin (Sn) to high-strength aluminum-zinc-magnesium (Al-Zn-Mg) alloys effectively suppresses hydrogen (H) embrittlement, which may be attributed to H absorption by the second-phase particles of Sn. To verify this fact, a simulation of H entry into the Sn phase in Al was performed using a model based on the reaction-diffusion equation that incorporates the solid solution energy of H evaluated by first-principles calculations. The results showed that the H solid solution site concentration of the second-phase particles must be at least five times higher than that of the Al phase for H absorption by the Sn second-phase particles to suppress H embrittlement. Therefore, the actual H embrittlement suppression effect of Sn second-phase particles is limited, and other factors may influence the suppression of H embrittlement in the experiment.

Development of elemental technologies of hand-foot-cloth monitors for -contamination visualization (Contract research); FY2022 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Hokkaido University*

JAEA-Review 2024-006, 54 Pages, 2024/06

JAEA-Review-2024-006.pdf:2.21MB

The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2022. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station (1F), Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2022, this report summarizes the research results of the "Development of elemental technologies of hand-foot-cloth monitors for -contamination visualization" conducted in FY2022. The present study aims to develop hand-foot-monitors for -contamination visualization and cloth monitors for /-contamination visualization consisting of a portable phoswich detector for measuring /-contamination distribution and energy to ensure the safety and security of workers involved in the decommissioning project of the 1F. The possibility of practical application of new scintillator materials and devices was examined with the goal of developing such new instruments.

Assessment of hydrogen embrittlement behavior in Al-Zn-Mg alloy through multi-modal 3D image-based simulation

Fujihara, Hiro*; Toda, Hiroyuki*; Ebihara, Kenichi; Kobayashi, Masakazu*; Mayama, Tsuyoshi*; Hirayama, Kyosuke*; Shimizu, Kazuyuki*; Takeuchi, Akihisa*; Uesugi, Masayuki*

International Journal of Plasticity, 174, p.103897_1 - 103897_22, 2024/03

https://doi.org/10.1016/j.ijplas.2024.103897

Hydrogen(H) embrittlement in high-strength aluminum(Al) alloys is a crucial problem. H accumulation at the interface of precipitates in Al alloy is considered to cause embrittlement. However, there is no quantitative knowledge regarding the interaction between H distribution and stress field near cracks. In this study, using a multi-modal three-dimensional image-based simulation combining the crystal plasticity finite element method and H diffusion analysis, we tried to capture the stress distribution near the crack, its influence on the H distribution, and the probability of crack initiation in the experimental condition. As a result, it was found that grain boundary cracks transition to quasi-cleavage cracks in the region where the cohesive energy of the semi-coherent interface of MgZn precipitates decreases due to H accumulation near the tip. We believe the present simulation method successfully bridges nanoscale delamination and macroscale brittle fracture.

Multi-modal 3D image-based simulation of hydrogen embrittlement crack initiation in Al-Zn-Mg alloy

Higa, Ryota*; Fujihara, Hiro*; Toda, Hiroyuki*; Kobayashi, Masakazu*; Ebihara, Kenichi; Takeuchi, Akihisa*

Keikinzoku, 73(11), p.530 - 536, 2023/11

https://doi.org/10.2464/jilm.73.530

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.

Experimental evaluation of scattered X-ray spectra due to X-ray therapeutic and diagnosis equipment for eye lens dosimetry of medical staff

Kowatari, Munehiko*; Nagamoto, Keisuke*; Nakagami, Koichi*; Tanimura, Yoshihiko; Moritake, Takashi*; Kunugita, Naoki*

Journal of Radiation Protection and Research, 47(1), p.39 - 49, 2022/03

https://doi.org/10.14407/jrpr.2021.00220

Influence of Zn injection on PWSCC crack growth rates and oxide film properties of Alloy 600

Chimi, Yasuhiro; Sato, Kenji*; Kasahara, Shigeki; Umehara, Ryuji*; Hanawa, Satoshi

Proceedings of Contribution of Materials Investigations and Operating Experience to Light Water NPPs' Safety, Performance and Reliability (FONTEVRAUD-9) (Internet), 10 Pages, 2018/09

To investigate the influence of Zinc (Zn) injection on primary water stress corrosion cracking (PWSCC) growth behavior, crack growth tests of 10% cold-worked Alloy 600 were performed in simulated primary water environment of pressurized water reactor (PWR) at 320C with a low-concentration (5-10 ppb) Zn injection under dissolved hydrogen (DH) conditions of 5, 30, and 50 cc/kgHO. As a result of the crack growth tests, DH-dependence of crack growth rate (CGR) showed a similar tendency to the predicted CGR based on the CGR data without Zn injection, indicating almost no effect of a low-concentration Zn injection on the crack growth behavior. Moreover, the microstructural analyses of oxide films formed inside the crack and on the specimen surface were conducted, and the intake of Zn in the oxides was detected on the specimen surface, but not detected inside the crack. This result was considered to be the cause of no Zn injection effect on the crack growth behavior.

JAEA-ISCN development programs of advanced NDA technologies of nuclear material

Seya, Michio; Kobayashi, Naoki; Naoi, Yosuke; Hajima, Ryoichi; Soyama, Kazuhiko; Kureta, Masatoshi; Nakamura, Hironobu; Harada, Hideo

Book of Abstracts, Presentations and Papers of Symposium on International Safeguards; Linking Strategy, Implementation and People (Internet), 8 Pages, 2015/03

https://www.iaea.org/safeguards/symposium/2014/home/eproceedings/sg2014-papers/000069.pdf

https://www.iaea.org/safeguards/symposium/2014/home/eproceedings/sg2014-slides/000069.pdf

JAEA-ISCN has been implementing basic development programs of the advanced NDA technologies for nuclear material (NM) since 2011JFY (Japanese Fiscal Year), which are (1) NRF (Nuclear resonance fluorescence) NDA technology using laser Compton scattered (LCS) -rays (intense mono-energetic -rays), (2) Alternative to He neutron detection technology using ZnS/BO ceramic scintillator, and (3) NRD (Neutron resonance densitometry) using NRTA (Neutron resonance transmission analysis) and NRCA (Neutron resonance capture analysis). These programs are going to be finished in 2014JFY and have demonstration tests in February - March 2015.

High spatial resolution ZnO scintillator for an in situ imaging device in EUV region

Arita, Ren*; Nakazato, Tomoharu*; Shimizu, Toshihiko*; Yamanoi, Kohei*; Empizo, M.*; Hori, Tatsuhiro*; Fukuda, Kazuhito*; Minami, Yuki*; Sarukura, Nobuhiko*; Maruyama, Momoko; et al.

Optical Materials, 36(12), p.2012 - 2015, 2014/10

https://doi.org/10.1016/j.optmat.2014.01.031

A single shot image of a ZnO crystal excited by the EUV laser of Kansai Photon Science Institute was captured. The evaluated EUV beam waist radii from the ZnO emission pattern along the horizontal and vertical axes are 5.0 and 4.7m, respectively. The expected focal spot size of EUV laser and the spatial resolution of the magnifier (including the Schwarzschild objectives and lenses) are however 1 and 4m, respectively. The discrepancy on the spatial resolutions is attributed to exciton diffusion. We estimated the ZnO exciton diffusion length from the effective decay time which is shortened by exciton-exciton collision quenching and which is dependence on excitation energy density. Our results indicate that the short lifetime of ZnO is required to improve the spatial resolution.

Hydrogen at zinc vacancy of ZnO; An EPR and ESEEM study

Son, N. T.*; Isoya, Junichi*; Ivanov, I. G.*; Oshima, Takeshi; Janzn, E.*

AIP Conference Proceedings 1583, p.341 - 344, 2014/02

Irradiation effects with 100 MeV Xe ions on optical properties of Al-doped ZnO films

Fukuoka, Osamu*; Matsunami, Noriaki*; Tazawa, Masato*; Shimura, Tetsuo*; Sataka, Masao; Sugai, Hiroyuki; Okayasu, Satoru

Nuclear Instruments and Methods in Physics Research B, 250(1-2), p.295 - 299, 2006/09

https://doi.org/10.1016/j.nimb.2006.04.146

We have investigated the effects on electrical and optical properties of Al-doped ZnO (AZO) semiconductor films induced by high-energy heavy ion. The AZO films with c-axis on SiO glass substrate were prepared by a RF-sputter-deposition method at 400 C. Rutherford backscattering spectroscopy shows that the Al/Zn composition and the film thickness are 4 % and 0.3 m. No appreciable change was observed in optical transparency. We find that the conductivity monotonically increases from 1.510 to 810 S/cm with increasing the fluence up to 410/cm, as already been observed for 100 keV Ne irradiation. The fluence of 100 keV Ne at which the conductivity takes its maximum is 310/cm (7 dpa). The dpa of 100 MeV Xe at 410/cm is estimated as 0.008. Hence, the conductivity increase by 100 MeV Xe ion is ascribed to the electronic excitation effects.