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.

Concentration dependence of constituent elements on grain boundary migration in high-entropy alloys

Shiotani, Kohei; Niiyama, Tomoaki*; Shimokawa, Tomotsugu*

Materials Transactions, 66(6), p.704 - 711, 2025/04

https://doi.org/10.2320/matertrans.MT-Z2025001

no abstracts in English

Solvent extraction behaviors of rhodium and palladium in nitric acid solutions using amide extractants

Ito, Kengo*; Morita, Misaki*; Araki, Yuta*; Kato, Chizu*; Fukutani, Satoshi*; Matsumura, Tatsuro; Fujii, Toshiyuki*

Solvent Extraction Research and Development, Japan, 32(1), p.53 - 62, 2025/00

https://doi.org/10.15261/serdj.32.53

Rhodium (Rh) and Palladium (Pd) in high-level radioactive waste are primarily fission products. This Study focused on understanding the extraction behavior of these platinum group elements (PGEs) using the novel extractants -hexaoctylnitriloacetamide (HONTA) and alkyl diamideamine (ADAAM). Both extractants showed affinity for Pd, with distribution coefficients significantly exceeding 1, demonstrating their effectiveness in Pd separation. In contrast, the distribution coefficients for Rh were consistently below 10 , indicating low extraction efficiency from nitric acid. However, by leveraging the salting-out effect with calcium nitrate hydrate, a distribution coefficient of 570 for Rh was achieved using HONTA. To overcome the difficult back-extraction of PGEs with HONTA, experiments were conducted using HEDTA and thiourea. Back-extraction with HEDTA in high-concentration nitric acid (2M) resulted in 90% extraction of Pd, while thiourea-based back-extraction with nitric acid yielded over 40% extraction for Rh, with the maximum of 62.7% achieved using hydrochloric acid.

Chiral gauge field in fully spin-polarized magnetic Weyl semimetal with magnetic domain walls

Ozawa, Akihiro*; Araki, Yasufumi; Nomura, Kentaro*

Journal of the Physical Society of Japan, 93(9), p.094704_1 - 094704_9, 2024/09

https://doi.org/10.7566/JPSJ.93.094704

Modulation of magnetization in magnetic Weyl semimetals leads to the shift of Weyl points in momentum space, which effectively serves as the chirality-dependent gauge field for the Weyl fermions. Here, we theoretically study such a magnetization-induced chiral gauge field, in a fully spin-polarized Weyl ferromagnet CoSnS. From a tight-binding model of CoSnS on stacked kagome lattice with magnetism, we calculate the magnetization-dependent evolution of the Weyl points in momentum space, resulting in the chiral gauge field. In the presence of the magnetic domain wall structure, we evaluate the chiral magnetic field arising from the spatial profile of the chiral gauge field. We find that a magnetic domain wall in CoSnS gives rise to a giant chiral magnetic field for the Weyl fermions, which reaches the order of a few hundred tesla to induce the Landau quantization. Such a giant chiral magnetic field may also influence the novel transport phenomena, such as the charge pumping by the domain wall motion, compatible with the spinmotive force.

Influence of interstitial carbon on bulk texture evolution of carbide-free high-entropy alloys during cold rolling using neutron diffraction

Fang, W.*; Liu, C.*; Zhang, J.*; Xu, P. G.; Peng, T.*; Liu, B.*; Morooka, Satoshi; Yin, F.*

Scripta Materialia, 249, p.116046_1 - 116046_6, 2024/08

https://doi.org/10.1016/j.scriptamat.2024.116046

Dual chiral density wave induced oscillating Casimir effect

Fujii, Daisuke; Nakayama, Katsumasa*; Suzuki, Kei

Physical Review D, 110(1), p.014039_1 - 014039_15, 2024/07

https://doi.org/10.1103/PhysRevD.110.014039

The Casimir effect is known to be induced from photon fields confined by a small volume, and also its fermionic counterpart has been predicted in a wide range of quantum systems. Here, we investigate what types of Casimir effects can occur from quark fields in dense and thin quark matter. In particular, in the dual chiral density wave, which is a possible ground state of dense quark matter, we find that the Casimir energy oscillates as a function of the thickness of matter. This oscillating Casimir effect is regarded as an analog of that in Weyl semimetals and is attributed to the Weyl points in the momentum space of quark fields. In addition, we show that an oscillation is also induced from the quark Fermi sea, and the total Casimir energy is composed of multiple oscillations.

Recrystallization of bulk nanostructured magnesium alloy AZ31 after severe plastic deformation; An in situ diffraction study

Liss, K.-D.*; Han, J.-K.*; Blankenburg, M.*; Lienert, U.*; Harjo, S.; Kawasaki, Takuro; Xu, P. G.; Yukutake, Eitaro*; Kawasaki, M.*

Journal of Materials Science, 59(14), p.5831 - 5853, 2024/04

https://doi.org/10.1007/s10853-023-09250-4

Adsorption behavior of platinum-group metals and Co-existing metal ions from simulated high-level liquid waste using HONTA and Crea impregnated adsorbent

Osawa, Naoki*; Kim, S.-Y.*; Kubota, Masahiko*; Wu, H.*; Watanabe, So; Ito, Tatsuya; Nagaishi, Ryuji

Nuclear Engineering and Technology, 56(3), p.812 - 818, 2024/03

https://doi.org/10.1016/j.net.2023.09.001

Experimental determination of phase equilibria in the Mn-Zn binary system

Imatomi, Daisuke*; Ishikawa, Ryosuke*; Nakata, Akira*; Ito, Tatsuya; Han, K.*; Nagasako, Makoto*; Xu, X.*; Omori, Toshihiro*; Kainuma, Ryosuke*

Journal of Phase Equilibria and Diffusion, 45(1), p.3 - 17, 2024/02

https://doi.org/10.1007/s11669-023-01068-6

Phase equilibria in the Mn-Zn binary system were experimentally determined by chemical composition examination, crystal structure determination, and thermal analysis. Major changes were detected for the , , and phases. The -B2 single-phase region could not be confirmed in the studied system because a disordered body-centered cubic structure, which is identical to the Mn phase, was confirmed in a quenched sample from the previously proposed region of phase. The phase has been controversial whether the phase is separated into , , and phases or not. By studying a diffusion couple and several alloy compositions, it was established that the , , and phases are not separate and comprise a single phase. Furthermore, the phase is not present in the Zn-rich region of the system because the corresponding invariant reactions were not detected via thermal analysis.

Quantitative measurement of figure of merit for transverse thermoelectric conversion in Fe/Pt metallic multilayers

Yamazaki, Takumi*; Hirai, Takamasa*; Yagi, Takashi*; Yamashita, Yuichiro*; Uchida, Kenichi*; Seki, Takeshi*; Takanashi, Koki

Physical Review Applied (Internet), 21(2), p.024039_1 - 024039_11, 2024/02

https://doi.org/10.1103/PhysRevApplied.21.024039