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論文

Effect of gauge volume on strain measurement in rock materials using time-of-flight neutron diffraction

阿部 淳*; 関根 孝太郎*; Harjo, S.; 川崎 卓郎; 相澤 一也

Physica B; Condensed Matter, 551, p.283 - 286, 2018/12

 パーセンタイル:100(Physics, Condensed Matter)

Our previous neutron diffraction measurements investigated strain accumulation mechanism(s) in rock materials under uniaxial compression. This technique, when applied to metallic materials, is suffered by surface effects, gauge volume size effects, and/or incident beam divergence that induce pseudo-strain. Knowledge of the pseudo-strain is therefore necessary for precise evaluation of strain value in a stressed rock material. This work investigated the effects of gauge volume and incident neutron beam divergence on pseudo-strain in rock materials via neutron diffraction experiments performed on three types of sandstone. Spurious peak shifts appeared depending on the gauge volume or incident neutron beam divergence. These peak shifts were inferred to be derived from the difference between a neutron-weighted center of gravity position and a geometric center of the gauge volume position. However, changing the gauge volume height did not cause shift in the peak position.

論文

Stroboscopic time-of-flight neutron diffraction during cyclic testing using the event data recording system at J-PARC

川崎 卓郎; 稲村 泰弘; 伊藤 崇芳*; 中谷 健; Harjo, S.; Gong, W.*; 相澤 一也

Journal of Applied Crystallography, 51(3), p.630 - 634, 2018/06

 被引用回数:1 パーセンタイル:47.84(Chemistry, Multidisciplinary)

A time-resolved time-of-flight neutron diffraction technique to characterize the structural properties of materials during cyclic tests has been developed. By adopting the developed technique, the behaviors of the crystal lattice and domains of the piezoelectric material in a multilayer-type piezoelectric actuator driven by a cyclic electric field were evaluated. The variation in diffraction intensity during the application of a cyclic electric field was obtained successfully, and the hysteresis-like behaviors of both the lattice strain and the 90$$^{circ}$$ domain switching were revealed.

論文

High stereographic resolution texture and residual stress evaluation using time-of-flight neutron diffraction

徐 平光; Harjo, S.; 小島 真由美*; 鈴木 裕士; 伊藤 崇芳*; Gong, W.; Vogel, S. C.*; 井上 純哉*; 友田 陽*; 相澤 一也; et al.

Journal of Applied Crystallography, 51(3), p.746 - 760, 2018/06

 被引用回数:1 パーセンタイル:47.84(Chemistry, Multidisciplinary)

Neutron diffraction texture measurements provide bulk textures with excellent grain statistics even for large grained materials, together with the crystallographic parameters and microstructure information such as phase fractions, coherent crystallite size, root mean square microstrain, macroscopic/intergranular stress/strain. The procedure for high stereographic resolution texture and residual stress evaluation was established at the TAKUMI engineering materials diffractometer. The pole figure evaluation of a limestone standard sample with a trigonal crystal structure suggested that the obtained precision for texture measurement is comparable with the oversea well-established neutron beam lines utilized for texture measurements. A high strength martensite-austenite multilayered steel was employed for further verification of the reliability of simultaneous Rietveld analysis of multiphase textures and macro stress tensors. By using a geometric mean micro-mechanical model, the macro stress tensor analysis with a plane stress assumption showed a RD-TD in-plane compressive stress (about -330 MPa) in martensite layers and a RD-TD in-plane tensile stress (about 320 MPa) in austenite layers. The phase stress partitioning was ascribed to the additive effect of volume expansion during martensite transformation and the linear contraction misfit during water quenching.

論文

Status report of the chopper spectrometer 4SEASONS

梶本 亮一; 中村 充孝; 稲村 泰弘; 蒲沢 和也*; 池内 和彦*; 飯田 一樹*; 石角 元志*; 村井 直樹; 吉良 弘*; 中谷 健; et al.

Journal of Physics; Conference Series, 1021(1), p.012030_1 - 012030_6, 2018/06

4SEASONS is a medium-resolution thermal neutron chopper spectrometer in the Materials and Life Science Experimental Facility (MLF) at J-PARC. Although 4SEASONS is routinely used for many experiments by internal and external users, upgrading and maintenance work is still underway. This paper reviews the recent improvements of the instrument.

論文

Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex, 2; Neutron scattering instruments

中島 健次; 川北 至信; 伊藤 晋一*; 阿部 淳*; 相澤 一也; 青木 裕之; 遠藤 仁*; 藤田 全基*; 舟越 賢一*; Gong, W.*; et al.

Quantum Beam Science (Internet), 1(3), p.9_1 - 9_59, 2017/12

J-PARC物質・生命科学実験施設の中性子実験装置についてのレビューである。物質・生命科学実験施設には23の中性子ビームポートがあり21台の装置が設置されている。それらは、J-PARCの高性能な中性子源と最新の技術を組み合わせた世界屈指の実験装置群である。このレビューでは、装置性能や典型的な成果等について概観する。

論文

Work hardening, dislocation structure, and load partitioning in lath-martensite determined by ${it in situ}$ neutron diffraction line profile analysis

Harjo, S.; 川崎 卓郎; 友田 陽*; Gong, W.*; 相澤 一也; Tichy, G.*; Shi, Z.*; Ungar, T.*

Metallurgical and Materials Transactions A, 48(9), p.4080 - 4092, 2017/09

AA2017-0020.pdf:3.33MB

${it in situ}$ neutron diffraction during tensile deformation of lath martensite steel containing 0.22 mass% of carbon, is performed using TAKUMI of J-PARC. The diffraction peaks at plastically deformed states exhibit asymmetries as the reflection of redistributions of the stress and dislocation densities/arrangements in lath-packets where the dislocation glides are favorable (soft packet) and unfavorable (hard packet). The dislocation density is as high as 10$$^{15}$$ m$$^{-2}$$ at the as-quenched state, and then during tensile straining, the load and the dislocation density become different between the two lath-packets. The dislocation character and arrangement vary also in the hard packet, but hardly change in the soft packet. The hard packet plays an important role in the high work hardening in martensite, which could be understood by taking into account not only the increase of the dislocation density but also the change in dislocation arrangement.

論文

Materials and Life Science Experimental Facility at the Japan Proton Accelerator Research Complex, 3; Neutron devices and computational and sample environments

坂佐井 馨; 佐藤 節夫*; 瀬谷 智洋*; 中村 龍也; 藤 健太郎; 山岸 秀志*; 曽山 和彦; 山崎 大; 丸山 龍治; 奥 隆之; et al.

Quantum Beam Science (Internet), 1(2), p.10_1 - 10_35, 2017/09

J-PARC物質・生命科学実験施設では、中性子検出器、スーパーミラーや$$^{3}$$Heスピンフィルターなどの光学機器、及びチョッパー等の中性子デバイスが開発され、据え付けられている。また、計算環境として機器制御、データ取得、データ解析、及びデータベースの4つのコンポーネントが整備されている。また、物質・生命科学実験施設では実験に使用される様々な試料環境が利用可能である。本論文では、これらの現状について報告する。

論文

Evaluation of bending strain in Nb$$_{3}$$Sn strands of CIC conductor using neutron diffraction

辺見 努*; Harjo, S.; 梶谷 秀樹*; 諏訪 友音*; 齊藤 徹*; 相澤 一也; 長村 光造*; 小泉 徳潔*

IEEE Transactions on Applied Superconductivity, 27(4), p.4200905_1 - 4200905_5, 2017/06

The superconducting property of Nb$$_{3}$$Sn strands is very sensitive to strain. The transverse electromagnetic loading has been considered as a major origin of the degradation of Nb$$_{3}$$Sn cable-in-conduit conductors (CICCs) due to the local bending. Since the bending pitch is around 5 mm due to contacting of strands compacted by the electromagnetic transverse loading, there is a possibility of a large bending strain with small deflection of strands. The bending strain of the strands cannot be evaluated from only the small deflection obtained visually. Measuring bending strain of Nb$$_{3}$$Sn strand in CICCs is important for evaluating the conductor performance. Neutrons, which have a large penetration depth, are a powerful tool to evaluate the internal strain of Nb$$_{3}$$Sn in the CICC. This paper shows that the bending strain in Nb$$_{3}$$Sn strands of CICCs can be determined by the neutron diffraction profile nondestructively and quantitatively.

論文

Line profile analyses of a martensitic steel during continuous and stepwise tensile deformations

川崎 卓郎; Harjo, S.; Gong, W.; 相澤 一也

Journal of Physics; Conference Series, 746(1), p.012044_1 - 012044_6, 2016/10

The microstructure of the metallic material is widely investigated in order to understand mechanical properties of the material by line profile analysis for X-ray and neutron diffraction data. Neutron diffraction has an advantage for obtaining averaged information of the microstructure inside the bulky material owing to its high transmittance. Further, the variation of the microstructure in the material during mechanical process is able to be observed by in-situ measurements. The Convolutional Multiple Whole Profile (CMWP) fitting method is a state of the art technique for line profile analysis. The dislocation characteristics are evaluated from the shape of the peak profile including the tail by this technique. In this study, the dislocation characteristics in martensitic steels during tensile deformation were studied by in-situ neutron diffraction measurement using the Engineering Materials Diffractometer TAKUMI at J-PARC through line profile analysis using the CMWP fitting method.

論文

Dislocation characteristics in lath martensitic steel by neutron diffraction

Harjo, S.; 川崎 卓郎; Gong, W.; 相澤 一也

Journal of Physics; Conference Series, 746(1), p.012046_1 - 012046_7, 2016/10

BB2015-1438.pdf:0.82MB

 被引用回数:2 パーセンタイル:16.75

In situ neutron diffraction during tensile deformation of an as-quenched lath martensitic 22SiMn2TiB steel, was performed using a high resolution and high intensity time-offlight neutron diffractometer. The characterizations of dislocations were analyzed using the classical Williamson-Hall (cWH) and modified Williamson-Hall (mWH) plots on the breadth method, and the convolutional multiple whole profile (CMWP) fitting method. As results, the dislocation density as high as 10$$^{15}$$ m$$^{-2}$$ in the as-quenched martensitic steel was determined. The dislocation density was found to decrease qualitatively with plastic deformation by the cWH and mWH plots, but hardly to change by the CMWP method. The scanning transmission electron microscopy observation supported the results of the latter method. In the CMWP method, the parameter $$M$$ that represents the arrangement of dislocations was found to decrease rapidly where a very high work hardening was observed.

論文

Recent progress in the chopper spectrometer 4SEASONS at J-PARC

梶本 亮一; 中村 充孝; 稲村 泰弘; 蒲沢 和也*; 池内 和彦*; 飯田 一樹*; 石角 元志*; 中島 健次; 河村 聖子; 中谷 健; et al.

JAEA-Conf 2015-002, p.319 - 329, 2016/02

4SEASONS ($textit{SIKI}$) is one of the three chopper spectrometers operating in MLF at J-PARC, and covers thermal neutron region ($$10^0$$ - $$10^2$$ meV) with relaxed resolution and high flux. The repetition rate multiplication by the Fermi chopper on this short length (18 m between the source and the sample) spectrometer enables wide-band multiple-incident-energy (multi-$$E_mathrm{i}$$) measurements, which proved to be useful in observing hierarchical structures in excitations over a large energy scale. On the other hand, the upgrading work of the spectrometer has been continued since the first inelastic scattering experiment in 2009. For examples, we took several measures to suppress background, installed new detectors recently, and are developing a new Fermi chopper now. In the presentation, we show examples of scientific outputs from the spectrometer which benefit from the multi-$$E_mathrm{i}$$ measurements, and recent or planned upgrades of the instrument.

論文

Dislocation characteristics of martensitic steel studied by ${it in situ}$ neutron diffraction experiment

川崎 卓郎; Harjo, S.; Gong, W.; 相澤 一也; 岩橋 孝明; Shi, Z.*; Li, J.*; 友田 陽*; Ung$'a$r, T.*

JPS Conference Proceedings (Internet), 8, p.031009_1 - 031009_5, 2015/09

鉄鋼材料に代表される金属材料の力学的特性を理解するためには、弾性ひずみだけでなく、転位の密度や配列状態など微細構造を評価することが重要である。これらの情報はX線や中性子回折パターンに表れるBraggピークの形状を詳しく解析することで得ることができる。透過能の高い中性子を用いることでバルク状態の材料内部の微細構造に関する情報を得ることができるが、これまで中性子(特にパルス中性子)はあまり適用されてこなかった。我々はJ-PARC物質生命科学実験施設BL19に設置された工学材料回折装置 匠を用いてマルテンサイト鋼の引張り試験その場中性子回折測定を行い、CMWP法と呼ばれる解析法を用いてこの材料の微細構造を調べた。その結果、巨視的なひずみの増加に伴う転位密度の増加は比較的小さく、転位配列の顕著な規則化が観測された。

論文

Thermal strain in superconducting Nb$$_{3}$$Sn strand at cryogenic temperature

Harjo, S.; 川崎 卓郎; 辺見 努; 伊藤 崇芳*; 中本 建志*; 相澤 一也

JPS Conference Proceedings (Internet), 8, p.031001_1 - 031001_5, 2015/09

Measurements of thermal strains in the superconducting constituent (Nb$$_{3}$$Sn phase) in Nb$$_{3}$$Sn strand were performed using BL19 Takumi of MLF, J-PARC. Lattice parameters of Nb$$_{3}$$Sn phase change continuously with increasing temperature. To avoid the thermal expansion effect, lattice parameters of the filaments (extracted from the strand) measured at the same temperatures were used to estimate the thermal strains in Nb$$_{3}$$Sn phase. As results, thermal strains for axial direction below 50 K are kept roughly constant at large compressive values, while the values are much lower (the difference is $$sim$$0.13%) than that measured at room temperature.

論文

Development status of the NMR system for the polarized $$^{3}$$He Neutron Spin Filter (NSF) in the MLF at J-PARC

酒井 健二; 奥 隆之; 林田 洋寿*; 吉良 弘*; 廣井 孝介; 猪野 隆*; 大山 研二*; 大河原 学*; 加倉井 和久; 篠原 武尚; et al.

JPS Conference Proceedings (Internet), 8, p.036015_1 - 036015_6, 2015/09

$$^{3}$$Heの中性子吸収断面積が強いスピン選択性を有することを利用した偏極$$^{3}$$Heフィルターは、ビーム調整が不要なため、ビームラインに設置すれば直ぐに使える簡便な中性子スピンフィルター(NSF)として利用できる。そのようなNSF実現のためには、NSFの$$^{3}$$He偏極度${it P}$を定常的にモニタするための核磁気共鳴(NMR)システムの開発が不可欠である。我々は断熱高速通過型(AFP)とパルス型NMRの特徴が相補的であることに着目して2つのシステムを併用した汎用性の高いNMRシステムを開発した。更に、J-PARCの中性子実験装置(BL10)での中性子透過率測定から得られた${it P}$で校正しながら、温度、パルスNMRの振動磁場の大きさや印可時間などの測定条件を変えて、AFPとパルスNMRの信号間の相関を測定した。例えば、パルスNMR測定に起因する減偏極率を0.1%以下になるまでパルスNMRの検出感度を小さくしても、2つのNMR信号間の線形性は確認できた。これらの結果から、我々は開発したNMRシステムが$$^{3}$$He偏極度モニタとして十分機能することを確認した。

論文

Effect of prior martensite on bainite transformation in nanobainite steel

Gong, W.; 友田 陽*; Harjo, S.; Su, Y.; 相澤 一也

Acta Materialia, 85, p.243 - 249, 2015/02

 被引用回数:45 パーセンタイル:1.72(Materials Science, Multidisciplinary)

その場中性子回折法、走査型電子顕微鏡および電子線後方散乱回折法による 部分焼き入れ有り及び無しによって523Kと573K恒温保持中ベイナイト相変態挙動を比較した。マルテンサイトを導入することによりベイナイト変態速度が加速されることを見出した。レンズマルテンサイト晶に隣接して、結晶方位の近いベイナイトラスが生成している。マルテンサイト変態ひずみはオーステナイトの塑性変形によって応力緩和されるので、これによって導入された転位はベイナイト変態を促進し、強いバリアント選択則をもたらすことがわかった。

論文

Development of a compact vertical splitting system for the cold neutron beam at JRR-3

田村 格良; 丸山 龍治; 山崎 大; 中村 清; 山本 和喜; 相澤 一也; 曽山 和彦

Journal of Physics; Conference Series, 528, p.012012_1 - 012012_7, 2014/07

 パーセンタイル:100

中性子ビーム実験装置の効率的な利用をするために、新たに開発した小型分岐装置を使用してJRR-3のC2冷中性子ビームラインの中性子ビーム実験装置を再配置した。この小型分岐装置は2つの小型マルチチャンネルベンダーを有している。これらのベンダーは0.2mm厚さのシリコン基板の両面にコーティングされたNi/Tiスーパーミラーを使用している。2つのベンダーの曲率半径は938mmであり、20$$^{circ}$$に曲げるベンダーの長さは320mmである。原子力機構のイオンビームスパッタリング装置を使用して、ベンダーに使用するm=3のスーパーミラーをシリコン基板の両面に成膜した。20$$^{circ}$$に曲げるベンダーの出口に設置された中性子ガイド末端の中性子束を金箔の放射化法により測定した結果、1.58$$times$$10$$^{7}$$ n/cm$$^{2}$$/sであった。本研究は、高い反射率を有する両面上に成膜されたスーパーミラーが小型分岐装置に適していることを示した。

論文

Development of portable polarized $$^{3}$$He neutron spin filter and its application to magnetic field imaging at J-PARC

酒井 健二; 奥 隆之; 林田 洋寿; 吉良 弘*; 篠原 武尚; 及川 健一; 原田 正英; 加倉井 和久; 相澤 一也; 新井 正敏; et al.

Journal of Physics; Conference Series, 528, p.012016_1 - 012016_7, 2014/07

 パーセンタイル:100

中性子偏極実験において測定領域を熱外中性子まで広げることは興味深い。その実現には、$$^{3}$$He自身の核スピンを反転することで、冷から熱外まで幅広いエネルギー領域の中性子のスピン偏極と反転が可能な偏極$$^{3}$$Heスピンフリッパー(PHSF)が重要な役割を果たす。現在、J-PARC/MLFでは「可搬型PHSF」の開発を進めている。この装置は、$$^{3}$$Heガスを封入したガラスセルを、$$^{3}$$Heスピン偏極を保持するための直径20cm,長さ30cmの小型ソレノイド内に設置する。さらに、ガラスセルをレーザー照射することで、光ポンピング法(SEOP)により$$^{3}$$Heを偏極した後に、ソレノイドごと中性子ビームラインに移動することで、可搬型PHSFとして利用する。われわれは、MLFの中性子ビームライン(BL10)で、PHSFの特性試験を行い、$$^{3}$$He核スピン反転前後の中性子透過率比の2次元分布測定から、本装置がPHSFとして十分機能することや、サンプルコイルの簡単な磁気イメージを測定できることを実証した。

論文

Engineering & Related Studies at J-PARC

Harjo, S.; 相澤 一也; 阿部 淳*; Gong, W.; 伊藤 崇芳*; 川崎 卓郎; 岩橋 孝明

Materials Science Forum, 777, p.12 - 18, 2014/04

Current status of a dedicated neutron diffractometer (TAKUMI) for investigations of stresses and crystallographic structures in engineering components, that has been built at Materials and Life Science Facility of J-PARC, was introduced as well as the engineering studies done there. Several topics recently performed at TAKUMI were selected to be introduced; internal strains in an ITER central solenoid conductor sample, internal strains in a rebar embedded in an air-cured concrete, deformation behavior TRIP steels at RT and tensile behavior of LPSO Mg-Zn-Y alloys. These topics and the relevant results showed that TAKUMI is a powerful neutron diffractometer for various engineering studies.

論文

Deformation behavior of an austenitic steel by neutron diffraction

Harjo, S.; 阿部 淳; 相澤 一也; Gong, W.; 岩橋 孝明

JPS Conference Proceedings (Internet), 1, p.014017_1 - 014017_6, 2014/03

An austenitic stainless steel type 304, which is one of the most popular materials in use, was tensile deformed and in situ neutron diffraction measurement was performed. The neutron diffraction measurement was conducted using the engineering materials diffractometer installed at MLF/J-PARC. Because of the combination of the high neutron intensity, the high counting rate and an event data recording method, in situ neutron diffraction during tensile loading at plastic deformation could be performed without any interruption of load or displacement. Lattice strains observed during deformation were discussed on the crystal orientation dependence.

論文

Residual strains in ITER conductors by neutron diffraction

Harjo, S.; 辺見 努; 阿部 淳; Gong, W.; 布谷 嘉彦; 相澤 一也; 伊藤 崇芳*; 小泉 徳潔; 町屋 修太郎*; 長村 光造*

Materials Science Forum, 777, p.84 - 91, 2014/02

Measurements of internal strains in the superconducting phase in two cable-in-conduit conductors (CICC) for ITER were performed using an engineering materials diffractometer TAKUMI of J-PARC. From strain measurements in a CICC for the toroidal field magnet after a performance test of cyclic current, in 100 mm long cut bars, a peak broadening and a large relaxation on residual thermal strain were observed in Nb$$_{3}$$Sn phase at a portion received a high magnetic field (high field zone). Internal strain measurements were also conducted in a CICC for the central solenoidal magnets after the similar performance test, in the full-size shape as used in the performance test (3.6 m long) and in 100 mm long cut bars. From results of the measurements the performances degradations of the ITER conductors were clarified.

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