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徐 平光; Zhang, S.-Y.*; Harjo, S.; Vogel, S. C.*; 友田 陽*
Quantum Beam Science (Internet), 8(1), p.7_1 - 7_13, 2024/01
Comprehensive information about the 
microstructure and crystal structure evolution during the preparation/production processes of various materials is in great demand in order to precisely control the microstructure morphology and the preferred orientation characteristics for the excellent strength-ductility-toughness balance of advanced engineering materials. 
isothermal annealing experiments of cold rolled 17Ni-0.2C (mass %) martensitic steel sheets were carried out by using the TAKUMI and ENGIN-X time-of-flight neutron diffractometers, respectively. The inverse pole figures based on full-profile refinement were extracted to roughly evaluate the preferred orientation features along three principal sample directions of investigated steel sheets using the General Structure Analysis System (GSAS) software with built-in generalized spherical harmonic functions. The consistent rolling direction (RD) inverse pole figures from TAKUMI and ENGIN-X have confirmed that the time-of-flight neutron diffraction has high repeatability and statistical reliability, revealing that the principal preferred orientation evaluation of steel materials is available through 90
TD 
ND (transverse direction normal direction) rotation of the investigated specimen on the sample stage during two neutron diffraction experiments. Moreover, these RD, TD and ND inverse pole figures before and after in situ experiments were compared with the corresponding inverse pole figures recalculated respectively from the MUSASI-L complete pole figure measurement and the HIPPO in situ microstructure evaluation. The similar orientation distribution characteristics suggested that the principal preferred orientation evaluation method can be applied to in situ microstructure evolution of bulk orthorhombic materials and spatially resolved principal preferred orientation mappings of large engineering structure parts.
高橋 治*; 渋井 洋平*; 徐 平光; Harjo, S.; 鈴木 徹也*; 友田 陽*
Quantum Beam Science (Internet), 4(1), p.16_1 - 16_15, 2020/03
The characteristics of texture and microstructure of lean duplex stainless steels with low Ni content produced through hot rolling followed by annealing were investigated locally with electron backscatter diffraction and globally with neutron diffraction. Then, the ductile-brittle transition (DBT) behavior was studied by Charpy impact test. It is found that the DBT temperature (DBTT) is strongly affected by the direction of crack propagation, depending on crystallographic texture and microstructural morphology; the DBTT becomes extremely low in the case of fracture accompanying delamination. A high Ni duplex stainless steel examined for comparison, shows a lower DBTT compared with the lean steel in the same crack propagating direction. The obtained results were also discussed through comparing with those of cast duplex stainless steels reported previously (Takahashi et al., Tetsu-to-Hagane, 100(2014), 1150).
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：26 パーセンタイル：90.31(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.
友田 陽*; 関戸 信彰*; 徐 平光; 川崎 卓郎; Harjo, S.; 田中 雅彦*; 篠原 武尚; Su, Y. H.; 谷山 明*
鉄と鋼, 103(10), p.570 - 578, 2017/10
被引用回数：13 パーセンタイル：50.55(Metallurgy & Metallurgical Engineering)Various methods were employed to measure the austenite volume fraction in a 1.5Mn-1.5Si-0.2C steel. It has been confirmed that the volume fractions determined by transmission electron microscopy, scanning electron microscopy/electron back scatter diffraction, X-ray diffraction and neutron diffraction exhibit a general trend to become larger in this order, although the values obtained by X-ray and neutron diffraction are similar in the present steel because austenite is relatively stable. The austenite volume fractions determined by diffraction methods have been found to be affected by the measuring specimen direction, i.e., texture, even by applying the conventional correcting procedure. To avoid this influence, it is recommended to measure both of volume fraction and texture simultaneously using neutron diffraction. Although synchrotron X-ray shows higher angle resolution, its small incident beam size brings poor statistic reliability. The influence of texture cannot be avoided for transmission Bragg edge measurement, either, which must be overcome to realize 2D or 3D volume fraction mapping.
友田 陽*; 佐藤 成男*; Uchida, M.*; 徐 平光; Harjo, S.; Gong, W.; 川崎 卓郎
Materials Science Forum, 905, p.25 - 30, 2017/08
Microstructural change during hot compressive deformation at 700 C followed by isothermal annealing for a Fe-32Ni austnitic alloy was monitored using neutron diffraction. The evolution of deformation texture with 40% compression and its change to recrystallization texture during isothermal annealing were presented by inverse pole figures for the axial and radial directions. The change in dislocation density was tracked using the convolutional muli-profile whole profile fitting method. To obtain the fitting results with good statistics, at least 60 s time-slicing for the event-mode recorded data was needed. The average dislocation density in 60 s after hot compression was determined to be 2.8 
10
m
that decreased with increasing of annealing time.
徐 平光; 友田 陽*; 新垣 優; Harjo, S.; 末吉 仁*
Materials Characterization, 127, p.104 - 110, 2017/05
被引用回数：43 パーセンタイル：93.45(Materials Science, Multidisciplinary)The volume fractions of austenite (
) in TRIP steels were evaluated using time-of-flight neutron diffraction through four methods. They include the analysis method with random texture assumption, the correction method of (
) peak intensities, the Rietveld refinement method using the summed spectrum without distinguishing the specimen orientations, and the combined Rietveld analysis method for textures and volume fractions. It was found that for a near-random spectrum obtained by the summation of all the measured neutron spectra, the Rietveld refinement provided a satisfactory precision for . Moreover, the precision was further improved through the combined Rietveld analysis method. If the texture measurement is unavailable, it is suggested to measure the neutron spectrum along the transverse direction, and to analyze the using conventional correction method of () peak intensities. It was also confirmed that the increment of evidently improved the combinations of tensile strength and uniform elongation (TSUEl).
徐 平光; Harjo, S.; 伊藤 崇芳*; 森井 幸生*; Gong, W.; 鈴木 裕士; 秋田 貢一; 鈴木 徹也*; 友田 陽; Lutterotti, L.*
JPS Conference Proceedings (Internet), 8, p.031022_1 - 031022_6, 2015/09
The current status of bulk texture measurements both using angle dispersive neutron diffraction and time-of-flight neutron diffraction at JAEA was briefly reviewed, then the effect of sample orientation coverage in the time-of-flight neutron diffraction on the reliability of reconstructed pole figure on the reliability of reconstructed pole figure was simply compared after the simultaneous Rietveld texture analysis. The similar texture results obtained at different orientation coverage levels suggests that it is possible to reduce the sample rotation times reasonably during the bulk texture measurement.
徐 平光; 友田 陽*; Vogel, S. C.*; 鈴木 徹也*; 米村 雅雄*; 神山 崇*
Reviews on Advanced Materials Science, 33(5), p.389 - 395, 2013/08
The ferrite-to-austenite transformation during heating and the austenite-to-ferrite transformation during cooling were investigated by KEK/SIRIUS and LANSCE/HIPPO neutron diffractometers under the stress-free condition. The deviation of ferrite lattice parameter from the linear thermal expansion and contraction during heating and cooling suggested the compressive strain occurred in ferrite phase. The texture memory effect between the cold compression texture of initial martensite and the final texture of ferrite after 
-
- phase transformation was interrupted by the static recrystallization of martensite during step-by-step heating, revealing that the occurrence of texture memory effect was not directly related to the deformation stored energy but related to the transformation strain and the strong variant selection for nucleation.
徐 平光; 友田 陽*; Vogel, S. C.*
軽金属学会平成24年度第2回加工と熱処理による優先方位制御研究部会公開講演会資料, p.21 - 22, 2012/10
フェライトからオーステナイトを経由して再びフェライトへの低合金鋼拡散変態において、加熱前のフェライト集合組織と冷却終了後のフェライト集合組織の間でよく観察された集合組織の記憶現象はバリアント選択則を用いて検討されてきた。しかし、拡散相変態の中間過程のその場観察例はなく、バリアント選択メカニズムにはまだ不明な点がある。本研究ではSIRIUS中性子回折装置を用い、段階的な加熱と冷却中の低合金マルテンサイト鋼のオーステナイト変態,フェライト変態及び熱膨張過程をその場で観察した。また、HIPPO中性子回折装置を用い、冷間圧縮した低合金鋼の拡散変態中の変態集合組織の変化をその場で測定した。段階的な加熱・冷却中に、低合金マルテンサイト鋼は2相域の格子常数が線形膨張直線より偏倚することから内部応力の存在を確認した。これはフェライトからオーステナイトを経由して再びフェライトへの拡散変態の集合組織記憶効果に関連すると考えられる。
徐 平光; 友田 陽*
Recrystallization, p.87 - 108, 2012/03
Grain refinement is an important fundamental research field for the development of high strength-toughness structural steels. The conventional thermo-mechanically controlled process of ferrite or ferrite-pearlite steels may refine the grain size to 5 microns. The ultrafine grained ferrite microstructure obtained by dynamic recrystallization can be realized at more than 1.2 true strain at about 873K and the grain size is dependent on the true strain. The annealing of cold rolled martensite steel may obtain ultrafine grained microstructure. However, the cold rolling of martensite steel needs much higher loading capacity of mills and the microcracks may occur in the surface. We proposed a new way to realize the grain refinement by warm compression/rolling of martensite steels through dynamic recrystallization and this technique has been applied to get ultrafine grained ferrite-cementite and ferrite-austenite duplex microstructures. In addition, the neutron diffraction has been applied to in situ investigate the precipitation of austenite and the recrystallization of ferrite. In this monographic chapter, the above research progress about dynamic recrystallization was systematically summarized, and the in situ neutron diffraction was emphasized as a powerful tool suitable for clarifying the microstructure evolution.
neutron diffraction徐 平光; Harjo, S.; 伊藤 崇芳; 鈴木 裕士; 秋田 貢一; Li, J.*; 友田 陽*
材料とプロセス(CD-ROM), 24, p.547 - 549, 2011/03
Ultrafine grained austenite-ferrite duplex steels have much better strength-ductility than ultrafined grained ferrite-cementite steels, because the large volume of dispersive austenite can increase the work hardening ability and prevents the early necking phenomenon. However, the crystallographic observation is urgently needed to clarify the competition behavior between the precipitation of austenite and the recrystallization of ferrite considering the meta-stability of low-carbon austenite, which is very important for the development of new-generation commercial austenite-ferrite duplex steel. In this paper, TAKUMI time-of-flight (TOF) neutron diffractometer at JAEA/J-PARC was employed to carry out the in situ neutron diffraction during isothermal annealing and MUSASI-L angle dispersive neutron diffractometer at JAEA/JRR-3 was used to confirmed the changes of crystallographic textures at room temperature. The GSAS Rietveld refinement of neutron diffraction spectra showed that the annealing treatment promoted the solute carbon in martensite to diffuse into the precipitated austenite. In addition, the inverse pole figures and crystallographic textures of ferrite based on the GSAS Rietveld spectrum refinement showed a clear difference in crystallographic orientation before and after 823K isothermal annealing, which was related to the recrystallization of ferrite.
友田 陽*; 徐 平光; Oliver, E. C.*; Paradowska, A.*
In-Situ Studies with Photons, Neutrons and Electrons Scattering, p.175 - 190, 2010/12
Neutron diffraction has been employed to study microstructural evolution in situ during heat treatment or thermo-mechanically controlled process for low alloy steels. Transformation kinetics, texture, carbon enrichment and internal stresses can be tracked and these data are useful to develop new processing to realize optimum microstructures.
Koo, M.*; 徐 平光; 友田 陽*; 鈴木 裕士
Scripta Materialia, 61(8), p.797 - 800, 2009/10
被引用回数：23 パーセンタイル：71.84(Nanoscience & Nanotechnology)角度分散法その場中性子回折を用い、高合金ベイナイト鋼のベイナイト相変態挙動を観察した。熱膨張測定中の中性子実験を行い、加熱,冷却と等温保持中のオーステンナイト111とフェライト110回折のプロファイルを記録した。中性子回折の結果は熱膨張の結果とよく一致した。オーステンナイトの回折ピック幅の広がりはベイナイト変態する前ではなく、変態開始後に起こることを示した。
Zhang, S. Y.*; Godfrey, E.*; Kockelmann, W.*; Paradowska, A.*; Bull, M. J.*; Korsunsky, A. M.*; Abbey, B.*; 徐 平光; 友田 陽*; Liljedahl, D.*; et al.
Materials Today, 12(7-8), p.78 - 84, 2009/07
被引用回数：19 パーセンタイル：51.09(Materials Science, Multidisciplinary)中性子回折は格子面間隔の精密評価に基づいて結晶材料内部の弾性歪みを直接測定できる。無材料除去のままで実際部品の内部組織や変形因子の変化などを非破壊測定的に評価するため、この技術は現代工程材料の設計や古代器物の材料考古学などの分野に特に有効である。本文はISIS核破砕型パルス中性子源に備えたEngin-X中性子回折装置における多数代表性試験研究にめぐって、中性子回折技術は材料科学の深入解明から産業への実際利用まで有効な基礎実験手法であることを示した。
Zhang, S. Y.*; Godfrey, E.*; Abbey, B.*; 徐 平光; 友田 陽*; Liljedahl, D.*; Zanellato, O.*; Fitzpatrick, M.*; Kelleher, J.*; Siano, S.*; et al.
Proceedings of World Congress on Engineering 2009, Vol.2, p.1412 - 1419, 2009/00
核破砕ソースからのパルス中性子ビームを用いた中性子回折や中性子イメージング技術による材料評価の多数の可能性を紹介した。具体的には、高温動的フェライト変態,航空複合結構件の低温残留応力,溶接部残留応力に及ぼす溶接手順の影響,飛行機エンジン・ニッケル合金部件の摩擦溶接応力の分析,古代青銅芸術品への応力分析の応用及び中性子応力イメージングなどの事例を紹介した。
徐 陽
International Congress Series, 1276, p.428 - 429, 2005/02
雷活動時の線量上昇の原因を明らかにするために、モンテカルロ計算による放射線挙動を解析した。本件では、ラドン子孫核種を線源とした場合の解析結果について報告する。その結果、Rn子孫核種では光子(線)束の有意な変動は見られないが、電子束の急激な上昇が示された。このため、Rnは線量上昇には寄与しないものの、電子密度の増加から雷放電に寄与している可能性が考えられた。本稿は、自然放射線関係の国際会議のプロシーディングス用原稿である。
徐 陽
第26回原子力産業セミナー, 0 Pages, 2004/10
FBRサイクル実用化戦略調査研究への取組み、国際協力等の現状について概説する。
and Cs
Ions in Compacted Bentonite佐藤 治夫; 徐 陽
Materials Research Society Symposium Proceedings, Vol.824, 0 Pages, 2004/00
ベントナイト中のIとCsイオンの拡散係数を乾燥密度、イオン強度、温度、粘土粒子の配向方向に対する拡散方向をパラメータに調べ、拡散係数及び活性化エネルギーに及ぼす配向方向、乾燥密度、イオン強度の影響について議論した。Iイオンは、主として外部間隙中を拡散し、Csイオンは、層間と外部間隙の両方を拡散し、イオン電荷に依存して主たる拡散移行経路が異なることが示された。
徐 陽
サイクル機構技報, (24), 0 Pages, 2004/00
FBRサイクル実用化戦略調査研究の2004年度第1四半期(平成16年4月
6月)の概況についてまとめた。FBRシステムに関しては、Na冷却炉、重金属炉、ガス冷却炉、水冷却炉及び小型炉の検討状況を概説した。燃料サイクルシステムについては、再処理システム(湿式法、乾式法)及び燃料製造システム(簡素化ペレット法、振動充填法、鋳造法)の開発状況を報告した。総合評価については評価手法の検討状況について報告した。
徐 陽; 田川 明広; 上田 雅司; 山下 卓哉; Otsuka, Yusuke*; Osafune, Kazunori*; 西川 雅弘*
3rd International Conference on Non-destructive Te, 0 Pages, 2003/11
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