Technical basis for revising the fatigue crack growth rates for ferritic steels in the ASME Code Section XI

Hasegawa, Kunio; Yamaguchi, Yoshihito; Udyawar, A.*

Journal of Pressure Vessel Technology, 147(3), p.034501_1 - 034501_7, 2025/06

https://doi.org/10.1115/1.4067679

Role of solute hydrogen on mechanical property enhancement in Fe-24Cr-19Ni austenitic steel; An neutron diffraction study

Ito, Tatsuya; Ogawa, Yuhei*; Gong, W.; Mao, W.*; Kawasaki, Takuro; Okada, Kazuho*; Shibata, Akinobu*; Harjo, S.

Acta Materialia, 287, p.120767_1 - 120767_16, 2025/04

https://doi.org/10.1016/j.actamat.2025.120767

Development of scaling parameter S for negative stress ratios R based on trend in experimental data for fatigue crack growth rates of austenitic stainless steels for ASME code Section XI

Negyesi, M.*; Yamaguchi, Yoshihito; Hasegawa, Kunio; Lacroix, V.*; Morley, A.*

Journal of Pressure Vessel Technology, 147(2), p.021201_1 - 021201_7, 2025/04

https://doi.org/10.1115/1.4067484

Extension of the dynamical Kubo-Toyabe model for precise analysis of ion dynamics in solids by SR

Ito, Takashi; Kadono, Ryosuke*

Kotai Butsuri, 60(4), p.197 - 206, 2025/04

We extended the dynamical Kubo-Toyabe model to resolve inconsistencies in a conventional protocol for SR-based analysis of ion dynamics in solids. Our new model not only provides a means for quantitative analysis based on the immobile-muon assumption, but also offers a method to evaluate the validity of this assumption.

Development of a bio-based adhesive by polymerization of Boc-protected vinyl catechol derived from caffeic acid

Tanizaki, Shiho*; Kubo, Tomohiro*; Bito, Yosuke*; Mori, Shigeki*; Aoki, Hiroyuki; Sato, Kotaro*

RSC Sustainability (Internet), 3(4), p.1714 - 1720, 2025/04

https://doi.org/10.1039/D4SU00629A

Conceptual study of J-PARC Proton Beam Irradiation Facility

Meigo, Shinichiro; Iwamoto, Hiroki; Sugihara, Kenta*; Hirano, Yukinori*; Tsutsumi, Kazuyoshi*; Saito, Shigeru; Maekawa, Fujio

JAEA-Technology 2024-026, 123 Pages, 2025/03

JAEA-Technology-2024-026.pdf:14.22MB

Based on the design of the ADS Target Test Facility (TEF-T) at the J-PARC Transmutation Experimental Facility, a conceptual study was conducted on the J-PARC proton beam irradiation facility. This research was carried out based on the recommendations of the Nuclear Transmutation Technology Evaluation Task Force of the MEXT. The recommendations state that it is desirable to consider facility specifications that can make the most of the benefits of using the existing J-PARC proton accelerator while also solving the engineering issues of the ADS. We considered facilities that could respond to a variety of needs while reducing the facilities that were not needed in the TEF-T design. In order to clarify these diverse needs, we investigated the usage status of representative accelerator facilities around the world. As a result, it became clear that the main purposes of these facilities were (1) Material irradiation, (2) Soft error testing of semiconductor devices using spallation neutrons, (3) Production of RI for medical use, and (4) Proton beam use, and we investigated the facilities necessary for these purposes. In considering the facility concept, we assumed a user community in 2022 and reflected user opinions in the facility design. This report summarizes the results of the conceptual study of the proton irradiation facility, various needs and responses to them, the roadmap for facility construction, and future issues.

Reduction and phase transformation of Ce-doped zirconolites

Hayashizaki, Kohei; Hirooka, Shun; Yamada, Tadahisa*; Sunaoshi, Takeo*; Murakami, Tatsutoshi; Saito, Kosuke

Ceramics (Internet), 8(1), p.24_1 - 24_12, 2025/03

https://doi.org/10.3390/ceramics8010024

Mechanistic origin of grain size and oxygen interstitial effects on strain-induced martensitic transformation in Ti-12Mo alloy

Chong, Y.*; Tsuru, Tomohito; Mitsuhara, Masatoshi*; Guo, B.*; Gholizadeh, R.*; Inoue, Koji*; Godfrey, A.*; Tsuji, Nobuhiro*

Communications Materials (Internet), 6, p.50_1 - 50_11, 2025/03

https://doi.org/10.1038/s43246-025-00777-4

Strain-induced martensitic phase transformation (SIMT) critically affects the mechanical properties of metastable titanium alloys. In this study, the effects of grain size and oxygen content on SIMT in a Ti-12wt.%Mo alloy were systematically investigated. It is found that SIMT is promoted by a decrease in grain size and in oxygen content. The mechanistic origins of the anomalous grain size dependency and the acute oxygen content dependency of SIMT are discussed based on multi-scale microstructural characterization and state-of-the-art simulations. Grain refinement does not raise the energy barrier for SIMT but rather provides more nucleation sites for strain-induced martensite, thereby promoting SIMT in fine-grained Ti-12wt.%Mo alloy. In contrast, for the Ti-12wt.%Mo-0.3 wt.%O alloy, oxygen atoms substantially increase the energy barrier for SIMT, due to a change in the local configuration of oxygen atoms during the phase transformation. In addition, atomprobe tomography reveals for the first time that oxygen atoms segregate at phase boundaries, thereby further restricting the growth of martensite.

Hydrogen embrittlement in Al-Zn-Mg alloys; Semispontaneous decohesion of precipitates

Shimizu, Kazuyuki*; Toda, Hiroyuki*; Hirayama, Kyosuke*; Fujihara, Hiro*; Tsuru, Tomohito; Yamaguchi, Masatake; Sasaki, Taisuke*; Uesugi, Masayuki*; Takeuchi, Akihisa*

International Journal of Hydrogen Energy, 109, p.1421 - 1436, 2025/03

https://doi.org/10.1016/j.ijhydene.2025.02.123

Our preceding investigation revealed that multiple hydrogen traps at coherent interfaces of MgZn precipitates initiated spontaneous interface decohesion, causing hydrogen-induced quasicleavage cracking in Al-Zn-Mg alloys. Herein, we performed a quantitative and systematic investigation to discern the mechanisms by which hydrogen trapped at coherent/semi-coherent interfaces of precipitates could influence macroscopic hydrogen embrittlement by modulating the coherent interface of MgZn through aging. To explore this hydrogen embrittlement phenomenon based on hydrogen trapping at the precipitate interface, we determined the hydrogen trapping energy of the semi-coherent MgZn interface via first-principles calculations (0.56 eV/atom). Hydrogen partitioning of all hydrogen trapping sites, including vacancies, grain boundaries, and coherent and semi-coherent MgZn interfaces, revealed that in overaged alloys, over 90% of the hydrogen was sequestered at semi-coherent interfaces. Owing to the inherent characteristics of the MgZn interface, the hydrogen sequestered at the semi-coherent interface decreased the interfacial cohesive energy, causing semispontaneous decohesion of the interface and quasicleavage fracture in the Al-Zn-Mg alloys. These results implied that intergranular fracture was not directly induced by hydrogen trapped at grain boundaries but rather by the decohesion of precipitate interfaces along grain boundaries.

Redox control in arsenic accumulation with organic matter derived from a varved lacustrine deposit in the Jurassic accretionary complexes

Masuki, Yuma*; Katsuta, Nagayoshi*; Naito, Sayuri*; Murakami, Takuma*; Umemura, Ayako*; Fujita, Natsuko; Matsubara, Akihiro*; Minami, Masayo*; Niwa, Masakazu; Yoshida, Hidekazu*; et al.

Journal of Hazardous Materials, 485, p.136843_1 - 136843_10, 2025/03

https://doi.org/10.1016/j.jhazmat.2024.136843

Lacustrine deposits have 30-fold higher As abundance than the average crustal deposit. Arsenic is mostly concentrated as discrete horizons deposited in spring and autumn. As-rich layers contain FeAsS, AsS, and AsS but As-rich hotspots mostly contain FeAsS. As accumulation to sediment is controlled by redox potential with organic matter.