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Gu, G. H.*; Jeong, S. G.*; Heo, Y.-U.*; Harjo, S.; Gong, W.; Cho, J.*; Kim, H. S.*; 他4名*
Journal of Materials Science & Technology, 223, p.308 - 324, 2025/07
被引用回数：0 パーセンタイル：0.00(Materials Science, Multidisciplinary)Face-centered cubic (FCC) equi-atomic multi-principal element alloys (MPEAs) exhibit excellent mechanical properties from cryogenic to room temperatures. At room temperature, deformation is dominated by dislocation slip, while at cryogenic temperatures (CTs), reduced stacking fault energy enhances strain hardening with twinning. This study uses in-situ neutron diffraction to analyze the temperature-dependent deformation behavior of Al
(CoNiV)
, a dual-phase (FCC/BCC) medium-entropy alloy (MEA). At liquid nitrogen temperature (LNT), deformation twinning in the FCC matrix leads to additional strain hardening through the dynamic Hall-Petch effect, giving the appearance of improved strengthening at LNT. In contrast, BCC precipitates show dislocation slip at both 77 K and 298 K, with temperature-dependent lattice friction stress playing a significant role in strengthening. The study enhances understanding of deformation behaviors and provides insights for future alloy design.
Lin, Z. M.*; Liu, B. X.*; Ming, K. S.*; 徐 平光; Yin, F. X.*; Zheng, S. J.*
Scripta Materialia, 263, p.116692_1 - 116692_7, 2025/07
被引用回数：0 パーセンタイル：0.00(Nanoscience & Nanotechnology)Complementary layer thickness effects on strength and plasticity in Q235 and SUS304 steels provide a novel strategy to realize high strength and high plasticity of heterogeneous Q235/SUS304 multilayered steel. In this work, the tensile deformation behaviors and fracture characteristics of vacuum hot-rolled Q235/SUS304 multilayered steel with various layer thicknesses ranging from 223 
m to 5 m were deeply investigated. The tensile strength improved with the reduction of layer thickness, and the uniform elongation were first increasing and then decreasing with the decrease of layer thickness, and the peak value appeared at the layer thickness of 20 m. Interestingly, the fracture elongation forms a high plateau value within the 10
20 m range. Further analysis reveals that the severe strain localization in the brittle SUS304 thin layers is delayed by the ductile Q235 layers, which is mainly attributed to the different texture evolution and dislocation configuration characteristics during tensile deformation.
Mao, W.*; Gong, W.; 川崎 卓郎; Gao, S.*; 伊東 達矢; 山下 享介*; Harjo, S.; Zhao, L.*; Wang, Q.*
Scripta Materialia, 264, p.116726_1 - 116726_6, 2025/07
被引用回数：0An ultrafine-grained 304 austenitic stainless steel exhibited pronounced serrated Luders deformation at 20 K, with stress and temperature oscillations reaching 200 MPa and 20 K. 
neutron diffraction and digital image correlation revealed discontinuous Luders band propagation and burst martensite formation. During deformation, austenite phase stress remained lower than at upper yielding, indicating elastic behavior. Notably, martensite phase stress stayed lower than austenite until fracture, likely due to stress relaxation from burst martensitic transformation at 20 K. The low martensite stress delayed brittle fracture until austenite plastically yielded during uniform deformation.
Park, M.-H.*; 柴田 曉伸*; Harjo, S.; 辻 伸泰*
Acta Materialia, 292, p.121061_1 - 121061_13, 2025/06
被引用回数：1Dual-phase (DP) steel, composed of soft ferrite and hard martensite, offers excellent strength-ductility balance and low cost. This study found that refining the DP microstructure enhanced both yield strength and strain hardening, improving strength and ductility. Digital image correlation (DIC) revealed strain localization in ferrite, but refinement reduced strain differences between ferrite and martensite, suppressing crack initiation. More ferrite/martensite interfaces promoted plasticity in martensite via enhanced deformation constraint. neutron diffraction showed martensite bore higher phase stress, which increased with refinement. By combining -DIC and neutron data, individual stress-strain curves for ferrite and martensite were constructed for the first time, explaining the strength-ductility synergy through interphase constraint. These findings offer guidance for designing heterostructured materials to overcome the strength-ductility trade-off.
-nonyl N,N-dimethylammonio)-propyl sulfate, present in isotropic solutions above its upper critical solution temperature丹治 珠緒*; 楠 裕翔*; 中川 太一; 高瀬 つぎ子*; 上田 祐生; 元川 竜平; Hinze, W. L.*; 高貝 慶隆*
Langmuir, 41(21), p.13184 - 13191, 2025/06
被引用回数：0The thermosensitive zwitterionic surfactant, C
APSO
, in solution displays a liquid-liquid miscibility gap exhibiting an upper critical solution temperature (UCST) in contrast to the lower critical temperature as is characteristic of nonionic surfactants. In this study, the micellar and aggregational properties of this surfactant in its homogeneous isotropic one phase region above the UCST was examined using surface tension and small-angle neutron scattering (SANS) measurements. The critical micelle concentration (CMC) of CAPSO was determined in both H
O and DO at 40 and 70
C as well as the cloud point temperature determined over a surfactant concentration range of 0.05-0.70 M. The CMC values were in the range of 48-55 mM (40C) and 61-65 mM (70C), respectively. The SANS data was analyzed using a core-shell model in which the CAPSO is represented by a nonyl hydrophobic core and polar [(N,N-dimethylammonio)-propylsulfate] headgroup shell. Results revealed that the CAPSO micelle aggregates are spherical in shape with a core diameter of 2.56 nm and shell thickness of 2.28 nm and an aggregation number of 30 at 40C. The data at 70C indicated that the aggregates were slightly larger in size, i.e., core diameter of 2.70 nm and shell thickness of 2.52 nm with an aggregation number of 35. At a fixed surfactant concentration, the aggregation number and size slightly decreased with a decrease in temperature from 70 to 40C.
町田 晃彦*; 齋藤 寛之*; 青木 勝敏*; 小松 一生*; 服部 高典; 佐野 亜沙美; 舟越 賢一*; 町田 真一*; 佐藤 豊人*; 折茂 慎一*
Physical Review B, 111(22), p.224413_1 - 224413_6, 2025/06
Mn金属を高温高圧で水素化することにより形成される反強磁性Mn重水素化物、fcc
-MnDxとhcp
-MnDxの結晶構造と磁気構造をin-situ中性子粉末回折により調べた。重水素原子はfcc及びhcp金属格子の八面体格子間を部分的に占有していた。N
el温度は-MnD
で543(10)Kであった。-MnD
では、飽和磁気モーメントは0.82(1)
、Nel温度は347(3)Kであった。-MnDと-MnDについて決定されたNel温度は、以前の研究で提案されたそれぞれのSlater-Pauling曲線によって予測されたものと一致した。更新されたNel温度は、電子バンド構造計算に基づくより正確なSlater-Pauling曲線の開発に示唆を与える。
Auh, Y. H.*; Neal, N. N.*; Arole, K.*; Regis, N. A.*; Nguyen, T.*; 小川 修一*; 津田 泰孝; 吉越 章隆; Radovic, M.*; Green, M. J.*; et al.
ACS Applied Materials & Interfaces, 17(21), p.31392 - 31402, 2025/05
MXenes are a promising class of 2D nanomaterials and are of particular interest for gas barrier application. However, MXene nanosheets naturally bear a negative charge, which prevents assembly with negatively charged polymers, such as polyacrylic acid (PAA), into gas barrier coatings. Here, we present MXene- and PAA-based layer-by-layer (MXene/PAA LbL) multilayers formed by leveraging hydrogen bonding interactions. When assembled in acidic conditions, MXene/PAA LbL films exhibit conformal, pin-hole free, nacre-like structures. The MXene/PAA LbL films yield high blocking capability and low permeability (0.14
0.01 cc mm m
day
MPa) for hydrogen gas. These nacre-like structures are also electronically conductive (up to 37030 S cm). Specifically, the reversible deconstruction of these films under basic conditions is experimentally verified. This study shows that hydrogen bonding interactions can be leveraged to form MXene LbL multilayers as gas barriers, electronically conducive coatings, and deconstructable thin films via pH control.
上田 祐生; Micheau, C.; 元川 竜平
ファインケミカル, 54(5), p.53 - 60, 2025/05
持続可能な社会を実現するためには金属資源のリサイクルが重要である。高濃度の金属イオンを取り扱う抽出操作では、プロセスの安全な運転を阻害する油相の相分離(第三相の生成)が長年の課題であった。本稿では、フルオラス化合物の強力な疎水性を利用した、第三相を生成させない新たな抽出系開発におけるこれまでの成果をまとめた。
Bi
Park, P.*; Ortiz, B. R.*; Spargue, M.*; Sakuya, A. P.*; Chen, S. A.*; Frontzek, M. D.*; Tian, W.*; Sibille, R.*; Mazzone, D. G.*; 田端 千紘; et al.
Nature Communications (Internet), 16, p.4384_1 - 4384_9, 2025/05
被引用回数：0Kagome metals with van Hove singularities (VHSs) near the Fermi level can host intriguing quantum phenomena, including chiral loop currents, electronic nematicity, and unconventional superconductivity. However, unconventional magnetic states driven by VHSs, such as spin-density waves (SDWs), have yet to be observed experimentally in kagome metals. Here, we present a comprehensive investigation of the magnetic and electronic structure of the layered kagome metal CeTiBi, where the Ti kagome electronic structure interacts with a magnetic sublattice of Ce
= 1/2 moments. Our findings establish the rare-earth Kagome metals LnTi3Bi4 as a model platform where characteristic electronic structure of the kagome lattice plays a pivotal role in magnetic order.
under pressureKnafo, W.*; Thebault, T.*; Raymond, S.*; Manuel, P.*; Khalyavin, D. D.*; Orlandi, F.*; Ressouche, E.*; Beauvois, K.*; Lapertot, G.*; 金子 耕士; et al.
Physical Review X, 15(2), p.021075_1 - 021075_16, 2025/05
The discovery of multiple superconducting phases in UTe boosted research on correlated-electron physics. This heavy-fermion paramagnet was rapidly identified as a reference compound to study the interplay between magnetism and unconventional superconductivity with multiple degrees of freedom. The proximity to a ferromagnetic quantum phase transition was initially proposed as a driving force to triplet-pairing superconductivity. However, we find here that long-range incommensurate antiferromagnetic order is established under pressure. The propagation vector k
= (0.07, 0.33, 1) of the antiferromagnetic phase is close to a wavevector where antiferromagnetic fluctuations have previously been observed at ambient pressure. These elements support that UTe is a nearly-antiferromagnet at ambient pressure. Our work appeals for theories modelling the evolution of the magnetic interactions and electronic properties, driving a correlated paramagnetic regime at ambient pressure to a long-range antiferromagnetic order under pressure. A deeper understanding of itinerant-f-electrons magnetism in UTe will be a key for describing its unconventional superconducting phases.
加藤 優*; Zheng, J.*; Deng, Y.*; 斎藤 史恵*; 鵜沼 佑規*; 岡 紗雪*; 田村 和久; 八木 一三*
ACS Catalysis, 15(10), p.7710 - 7719, 2025/04
被引用回数：0Nitrous oxide (NO) is a greenhouse and an ozone-depleting gas. Electrocatalytic NO reduction reaction (NORR) is known to be catalyzed at noble metal electrodes such as Pd and Pt, and the surface modification of such noble metals with Sn is known to increase the NORR in acidic media. However, the role of Sn at the surface remains unclear. In this work, NORR activity was investigated for single-crystalline Pt, Pd, and Pd-Pt electrodes with the (111) or (100) plane in the presence and absence of Sn at the electrode surface in acidic media. In situ X-ray crystal truncation rod (CTR) measurements of Sn-modified Pt(111) and Pd(111) electrodes revealed the presence of metallic Sn and SnO at their surfaces. The surface Sn modification enhances the NORR activity for Pd-Pt(100) or Pd(100) electrodes but not for the Pt(111), Pd-Pt(111), or Pt(100) electrodes.
hydridosilicate at high pressures; A Bridge to BaSiH
polyhydrideBeyer, D. C.*; Spektor, K.*; Vekilova, O. Y.*; Grins, J.*; Barros Brant Carvalho, P. H.*; Leinbach, L. J.*; Sannemo-Targama, M.*; Bhat, S.*; Baran, V.*; Etter, M.*; et al.
ACS Omega (Internet), 10(15), p.15029 - 15035, 2025/04
被引用回数：0 パーセンタイル：0.00(Chemistry, Multidisciplinary)SiH八面体部位を特徴とするヒドリドケイ酸塩は、水素貯蔵と水素化物イオン伝導に関連する潜在的な性質を持つかなり新しい化合物のクラスである。ここでは、Zintl相水素化物BaSiH
を4GPa以上の圧力でH流体と反応させ、その後常圧まで減圧して得られた新しい代表的なBaSiHについて報告する。SiH
イオンはBa
対イオンによって八面体に配位している。Ba原子とSi原子の配置は理想的なfcc NaCl構造からわずかにずれている。IRとラマンスペクトルからSiHの屈曲と伸縮モードがそれぞれ800-1200と1400-1800cmの範囲で観測された。BaSiHは95
Cまで熱的に安定であり、それ以上ではBaHとSiに分解する。DFT計算により、直接バンドギャップは2.5eVであることが示された。BaSiHの発見により、ギガパスカル圧力(10GPa以下)のシリサイドの水素化反応からアクセス可能なヒドリドケイ酸塩の化合物クラスが固まった。BaSiHの構造的性質は、超伝導ポリハイドライドBaSiHを予測されるより高い圧力で水素化するための中間体(あるいは前駆体)であることを示唆している。
Wang, Y.*; Gong, W.; Harjo, S.; 他7名*
Acta Materialia, 288, p.120840_1 - 120840_14, 2025/04
被引用回数：1 パーセンタイル：0.00(Materials Science, Multidisciplinary)Low yield strength and the presence of Luders bands constitute principal impediments to the extensive applications of conventional medium Mn steels with a duplex microstructure of ferrite and austenite. Flash heating and the concept of chemical heterogeneity have been combined to engineer a duplex austenite-martensite microstructure in medium Mn steels, which has proven effective in augmenting the yield strength and mitigating the occurrence of Luders bands. However, the underlying mechanisms remain ambiguous. In the present work, the effect of austenite stability on yielding behavior was systematically investigated in an austenite-martensite duplex medium Mn steel. Austenite stability was identified as the critical factor governing yield strength, where reduced stability promotes early stage deformation induced martensite transformation, thereby decreasing yield strength. Diminished austenite stability may as well induce enhanced work hardening, thereby result in the inclination and eventual elimination of yield plateau, concomitant with the disappearance of Luders bands. These observations expand our current understanding of the yielding behavior in medium Mn steels and offer insights for the design of other advanced high strength steels.
neutron diffraction study伊東 達矢; 小川 祐平*; Gong, W.; Mao, W.*; 川崎 卓郎; 岡田 和歩*; 柴田 曉伸*; Harjo, S.
Acta Materialia, 287, p.120767_1 - 120767_16, 2025/04
被引用回数：0 パーセンタイル：0.00(Materials Science, Multidisciplinary)Incorporating solute hydrogen into Fe-Cr-Ni-based austenitic stainless steels enhances both strength and ductility, providing a promising solution to hydrogen embrittlement by causing solid-solution strengthening and assisting deformation twinning. However, its impacts on the relevant lattice defects evolution (
, dislocations, stacking faults, and twins) during deformation remains unclear. This study compared the tensile deformation behavior in an Fe-24Cr-19Ni (mass%) austenitic steel with 7600 atom ppm hydrogen-charged (H-charged) and without hydrogen-charged (non-charged) using neutron diffraction. Hydrogen effects on the lattice expansion, solid-solution strengthening, stacking fault probability, stacking fault energy, dislocation density, and strain/stress for twin evolution were quantitatively evaluated to link them with the macroscale mechanical properties. The H-charged sample showed improvements in yield stress, flow stress, and uniform elongation, consistent with earlier findings. However, solute hydrogen exhibited minimal influences on the evolution of dislocation and stacking fault. This fact contradicts the previous reports on hydrogen-enhanced dislocation and stacking fault evolutions, the latter of which can be responsible for the enhancement of twinning. The strain for twin evolution was smaller in the H-charged sample compared to the non-charged one. Nevertheless, when evaluated as the onset stress for twin evolution, there was minimal change between the two samples. These findings suggest that the increase in flow stress due to the solid-solution strengthening by hydrogen is a root cause of accelerated deformation twinning at a smaller strain, leading to an enhanced work-hardening rate and improved uniform elongation.
Naeem, M.*; Rehman, A. U.*; Romero Resendiz, L.*; Salamci, E.*; Aydin, H.*; Ansari, P.*; Harjo, S.; Gong, W.; Wang, X.-L.*; 他3名*
Communications Materials (Internet), 6, p.65_1 - 65_13, 2025/04
The need for lightweight materials with mechanical integrity at ultralow temperatures drives the development of advanced alloys for cryogenic use. Additive manufacturing via laser powder bed fusion (LPBF) offers a scalable way to create alloys with tailored properties. Here, we show that LPBF-processed Al10SiMg exhibits a high ultimate tensile strength (395 MPa) and uniform elongation (25%) at 15 K. These enhancements stem from grain refinement, increased geometrically necessary dislocations, and stress partitioning between the Al matrix and the stiffer Si phase, aiding strain accommodation. neutron diffraction reveals that the Si phase, with its higher yield strength, bears most of the load, while the Al matrix undergoes continuous strain hardening, extending deformation capacity. These results highlight Al10SiMg's promise for cryogenic applications such as hydrogen storage, aerospace, and quantum computing hardware.
熊田 高之; 岩原 大輔*
Isotope News, (798), p.26 - 27, 2025/04
自動車用タイヤでは、シリカ微粒子をゴム材料中に添加することによりグリップ性能を損なうことなく燃費性能を改善させている。その鍵となるのが、シリカとゴムを結び付けるシランカップリング剤(SCA)である。SCAは脱水反応によってシリカと反応し、架橋や相互浸透によってゴム材料と結合する。ゴム材料と架橋できる適切な官能基を持たない長鎖アルキルSCAでは、ゴム材料との相互浸透が結合を支配する。我々は、スピンコントラスト変調中性子反射率法で、ブタジエンゴムとシリカの界面に生成したわずか2 nm厚のSCA層の膜厚と組成を決定できることを示した。
Pandian, K.*; Neikter, M.*; Ekh, M.*; Harjo, S.; 川崎 卓郎; Woracek, R.*; Hansson, T.*; Pederson, R.*
JOM, 77(4), p.1803 - 1815, 2025/04
被引用回数：0 パーセンタイル：0.00(Materials Science, Multidisciplinary)To produce dense Ti-6Al-4V components, electron beam powder bed fusion is typically followed by post-heat treatment like hot isostatic pressing (HIP). Standard HIP at 920C/100 MPa for 2 h coarsens the microstructure and reduces yield strength, while low-temp HIP at 800C/200 MPa for 2 h limits coarsening and retains strength comparable to as-built material. A coarser microstructure negatively affects tensile properties. Tensile tests at various temperatures suggest that thermally activated slip systems may influence elongation, requiring further study. In situ neutron time-of-flight diffraction during tensile loading enables analysis of strain evolution and slip plane activity. A two-phase elastic-plastic self-consistent model was used to compare with experiments. Results show basal slip {0002} activated at 20C, pyramidal slip {10-11} at 350C, and 
phase carrying higher stress than 
in the plastic regime.
Hu, F.-F.*; Qin, T.-Y.*; Ao, N.*; 徐 平光; Su, Y. H.; Parker, J. D.*; 篠原 武尚; 菖蒲 敬久; Kang, G.-Z.*; Ren, M.-M.; et al.
Journal of Traffic and Transportation Engineering (English Edition), 25(2), p.75 - 93, 2025/04
To accurately predict the remaining lifetime of surface-strengthened railway axles, a damage tolerance method considering three-dimensional (3D) residual stresses was proposed. By taking the induction-hardened carbon steel S38C axle as an example, two-dimensional (2D) distribution characterization of residual strain and 3D residual stress measurement were performed through comprehensive application of the neutron Bragg-edge transmission imaging and angle-dispersive neutron diffraction experiments. A numerical method was employed to implant the 3D residual stress into the axle model, and the remaining lifetime of the full-scale axle was studied by coupling the measured load spectrum, press-fit loads, and residual stresses. Experimental results shows that, both axial and hoop directions present a compressive residual strain gradient layer of about 3 mm, with a maximum compressive residual strain of up to -4500 
in the surface layer, yet a maximum tensile strain of up to 1000 in the core. The maximum axial and hoop compressive stresses of the axle are about -500 MPa and -303 MPa respectively, while radial stresses overall fluctuate in the zero mean stress range. At depths beyond 4.5 mm from the surface layer, all three components are tensile stresses. The axle surface layer is subjected to compressive residual stresses, and crack propagation does not occur if the crack depth is less than 4.5 mm. Nevertheless, cracks propagate accelerates when the crack depth is greater than 4.5 mm. Different crack propagation depth thresholds lead to a larger calculated remaining lifetime for the residual stress-free condition than for the case where 3D residual stresses are taken into account. However, the axle remaining service mileage of the axle of 227000 Km under the most conservative conditions exceeds 3.5 non-destructive inspection (NDI) cycles, with a large safety margin. The experimental results can provide a scientific reference for the development and optimization of NDI cycles for surface-strengthened railway axles.
Li, F.*; Tang, X.*; Fei, Y.*; Zhang, J.*; Liu, J.*; Lang, P.*; Che, G.*; Zhao, Z.*; Zheng, Y.*; Fang, Y.*; et al.
Journal of the American Chemical Society, 147(17), p.14054 - 14059, 2025/04
被引用回数：0 パーセンタイル：0.00(Chemistry, Multidisciplinary)2,2'-ビピラジン(BPZ)の圧力誘起重合により結晶性グラファンナノリボン(GANR)を合成した。中性子回折データのリートベルト精密化,核磁気共鳴スペクトル,赤外スペクトル,理論計算を行った結果、BPZは
積層した芳香環の間でディールス・アルダー重合し、並外れた長距離秩序を持つ伸びたボート型GANR構造を形成することがわかった。未反応の-C=N-基がボートの両端を橋渡ししており、さらなる機能化の余地がある。このGANRのバンドギャップは2.25eVであり、光電応答は良好である(I
/I
=18.8)。われわれの研究は、高圧トポケミカル重合法が、特定の構造と望んだ特性を持つグラファンの精密な合成に有望な方法であることを強調している。
山内 宏樹; 目時 直人; 綿貫 竜太*; Hong, T.*; Fernandez-Baca, J. A.*; 萩原 雅人; 益田 隆嗣*; 吉沢 英樹*; 伊藤 晋一*
Journal of the Physical Society of Japan, 94(5), p.054705_1 - 054705_8, 2025/04
The 
-electron states of NdB were determined by observing crystalline electric field (CEF) excitations with inelastic neutron scattering experiments. Our analysis yields CEF excitation energies of 2.8, 12.4, 17.2, and 25.4 meV. The -electron states are simply described by one of 
-multiplets 
with negligibly small mixing. The ground state is the pseudo-quartet consist of the ground doublet dominated by 
and the first excited doublet dominated by 
at 2.8 meV, which is consistent with magnetic specific heat and entropy reported in earlier study. The simple -electron states in NdB are the consequence of the strong uniaxial and in-plane isotropic CEF potential due to the local structure of Nd ions with point symmetry 
.
