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論文

Evaluation of residual stress relaxation in a rolled joint by neutron diffraction

林 眞琴*; Root, J. H.*; Rogge, R. B.*; 徐 平光

Quantum Beam Science (Internet), 2(4), p.21_1 - 21_16, 2018/12

The rolled joint of pressure tube, consisting of three axial symmetric parts, modified SUS403 stainless steel, Zr-2.5Nb pressure tube and Inconel-718, has been examined by neutron diffraction for residual stresses. It was heat treated at 350$$^{circ}$$C for 30, 130 and 635 hours to simulate the thermal aging of the rolled joint over the lifetime of the advanced thermal reactor at 288$$^{circ}$$C for 1, 5 and 30 years. The crystal lattice strains at various locations in the rolled joint before and after the aging treatments were measured by neutron diffraction and the residual stress distribution in the rolled joint was evaluated by using the Kroner elastic model and the generalized Hooke's law. In the crimp region of the rolled joint, it was found that the aging treatment had weak effect on the residual stresses in the Inconel and the SUS403. In the non-aged Zr-2.5Nb, the highest residual stresses were found near its interface with the SUS430. In the Zr-2.5Nb in the crimp region near its interface with the SUS430, the average compressive axial stress was -440 MPa, having no evident change during the long-time aging. In the Zr-2.5Nb outside closest to the crimp region, the tensile axial and hoop stresses were relieved during the 30 hours aging. The hoop stresses in the crimp region evolved from an average tensile stress of 80 MPa to an average compressive stress of 230 MPa after the 635 hours aging, suggesting that the rolled joint had a good long-term sealing ability against the leakage of high temperature water.

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

種々な方法によるMn-Si-C鋼の残留オーステナイト体積率測定の比較

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.; 谷山 明*

鉄と鋼, 103(10), p.570 - 578, 2017/10

 被引用回数:1 パーセンタイル:76.21(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.

論文

Quantitative evaluation of texture and dislocations during annealing after hot deformation in austenitic steel using neutron diffraction

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 $$^{circ}$$C followed by isothermal annealing for a Fe-32Ni austnitic alloy was monitored using ${it in situ}$ 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 $$times$$ 10$$^{14}$$ m$$^{-2}$$ that decreased with increasing of annealing time.

論文

放射光X線回折法を用いた積層型高強度鋼板におけるマルテンサイト層の局所変形挙動評価

小島 真由美*; 城 鮎美*; 鈴木 裕士; 井上 純哉*; 菖蒲 敬久; 徐 平光; 秋田 貢一; 南部 将一*; 小関 敏彦*

材料, 66(6), p.420 - 426, 2017/06

The strain distribution in a multilayered steel composite, which consists of martensite and austenite layers, was evaluated by energy dispersive X-ray diffraction to investigate the homogeneity of deformation in the martensite layer under uniaxial loading. A dog-bone shape specimen with a martensite layer with 0.2 mm in a thickness, sandwiching by austenite layers with 0.4 mm in thickness, was utilized in this study. A change in strains as a function of tensile loading was measured at the center of the martensite layer as well as near the interface between the martensite and austenite layers. Furthermore, the residual strain distributions were measured in the martensite layer of the unloaded specimens after different applied strains. As a result, slight inhomogeneous deformation was found at the beginning of the plastic deformation in the martensite layer although no local deformation was recognized even near the interface between austenite and martensite layers. After further deformation, mismatch of plastic deformation between austenite and martensite layers was reduced, and the martensite layer deformed homogeneously. Therefore, an unstable interface phenomenon might not be caused by the intrinsic factors with a mesoscopic scale discussed in this experiment.

論文

Evaluation of austenite volume fraction in TRIP steel sheets using neutron diffraction

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:10 パーセンタイル:5.06(Materials Science, Multidisciplinary)

The volume fractions of austenite ($$f_{rm A}$$) 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 ($$hkl$$) 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 $$f_{rm A}$$. 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 $$f_{rm A}$$ using conventional correction method of ($$hkl$$) peak intensities. It was also confirmed that the increment of $$f_{rm A}$$ evidently improved the combinations of tensile strength and uniform elongation (TS$$times$$UEl).

論文

Effect of storage environment on hydrogen generation by the reaction of Al with water

Wang, Y.-Q.*; Gai, W.-Z.*; Zhang, X.-Y.*; Pan, H.-Y.*; Cheng, Z.-X.*; 徐 平光; Deng, Z.-Y.*

RSC Advances (Internet), 7(4), p.2103 - 2109, 2017/01

AA2016-0521.pdf:1.55MB

 被引用回数:3 パーセンタイル:60.18(Chemistry, Multidisciplinary)

Al powder was stored in saturated water vapor, oxygen, nitrogen and drying air separately for a time period up to about six months, the degradation behavior of Al activity was characterized by the reaction of Al with water. It was found that water vapor decreased the induction time for the beginning of Al-water reaction and reduced the total hydrogen generation per unit weight of Al, while oxygen increased the induction time and retarded the Al-water reaction. In contrast, the effect of nitrogen and drying air on Al activity was weak. The mechanism analyses indicated that water vapor promoted the hydration of Al surface passive oxide film and speeded up the reaction of Al with water, while oxygen thickened the passive oxide film of Al surface and prolonged its hydration process. These imply that water vapor rather than oxygen is responsible for the degradation of Al activity during storage under ambient condition.

論文

中性子回折によるA1050アルミニウムの集合組織測定

徐 平光; Harjo, S.; 小貫 祐介*

加工と熱処理による優先方位制御, p.1 - 6, 2016/11

金属材料の加工性などの材料特性を考察するためには、材料全体の平均的な集合組織を明らかにする必要がある。高い透過能を有する中性子線を用いた集合組織測定では、材料全体の平均情報を一度に測定できる利点があり、研究用原子炉JRR-3の残留応力解析装置RESA-1や、大強度陽子加速器施設J-PARCにおける工学中性子回折装置TAKUMIとiMATERIAで実施可能である。本研究では、軽金属学会軽金属部会の共通アルミニウム合金試料を用いて、TAKUMIとiMATERIA装置による検出器パネルを分割した高精度集合組織測定技術の妥当性を検討した。両装置から得られた集合組織結果がX線回折結果とほぼ一致していることなどを示した。

論文

Rapid measurement scheme for texture in cubic metallic materials using time-of-flight neutron diffraction at iMATERIA

小貫 祐介*; 星川 晃範*; 佐藤 成男*; 徐 平光; 石垣 徹*; 齋藤 洋一*; 轟 秀和*; 林 眞琴*

Journal of Applied Crystallography, 49(5), p.1579 - 1584, 2016/10

AA2016-0186.pdf:1.13MB

 被引用回数:7 パーセンタイル:26(Chemistry, Multidisciplinary)

The authors have developed texture measurement system on a time-of flight neutron diffractometer, iMATERIA (BL20, MLF/J-PARC, Japan). Quantitative Rietveld texture analysis for a duplex stainless steel was possible with one neutron beam exposure for several minutes without sample rotation. The minimum number of diffraction spectra required for the Rietveld texture analysis was experimentally determined as $$sim$$100. The suggested rapid measurement scheme used 132 spectra and determined volume fractions of texture components in both ferrite and austenite phases, quantitatively. This quantitative and rapid measurement scheme was established by utilizing the features of iMATERIA as a powder diffractometer, i.e. fairly high resolution in d-spacing and numerous detectors equipped in a wide range of scattering angle.

論文

Kinetics study of the Al-water reaction promoted by an ultrasonically prepared Al(OH)$$_{3}$$ suspension

Liang, G.-H.*; Gai, W.-Z.*; Deng, Z.-Y.*; 徐 平光; Cheng, Z.*

RSC Advances (Internet), 6(42), p.35305 - 35314, 2016/04

AA2016-0023.pdf:1.41MB

 被引用回数:11 パーセンタイル:32.5(Chemistry, Multidisciplinary)

Hydrogen is an ideal fuel for fuel cells because its reaction byproduct with oxygen is environmentally benign. To resolve the safe storage and low cost transportation problem, the onsite hydrolysis reaction in water has been recently employed as a new-type portable hydrogen source. Metal Al is thought as a promising hydrogen-generation material due to its relative low price, light atomic weight and abundance in the earth. In order to promote the reaction of Al particles with water and weaken the inhabitation phenomenon of dense passive oxide film on Al surface, the effect of ultrasonically prepared Al(OH)$$_{3}$$ suspension on the kinetics of Al-water reaction was investigated in this paper. It is found that the induction time for the beginning of Al-water reaction decreases and the reaction rate increases with increasing the suspension concentration, volume and temperature, which is ascribed to the exothermic characteristics of Al-water reaction.

論文

Tensile deformation behavior of hydrogen charged ultrahigh strength steel studied by in situ neutron diffraction

徐 平光; Yin, J*; Zhang, S. Y.*

Acta Metallurgica Sinica, 51(11), p.1297 - 1305, 2015/11

The tensile deformation behavior of 1250 MPa ultra-high strength steels with and without hydrogen charging was comparably investigated using neutron diffraction together with the fracture morphology and microstructure observation. Before tensile loading, the (110) lattice spacing of hydrogen charged steel was found larger than that of non-charged sample while the (200) lattice spacing of the former was smaller than that of the latter, suggesting that the hydrogen atoms occupied the tetrahedral center promoted the increment of lattice plane spacing of (110) crystal planes while the balanced internal stress resulted in the proper decrement of (200) lattice plane spacing. In the non-charged sample, the non-linear elastic deformation was observed at 700 MPa in (200) planes, and then at 800 MPa in (110) planes. In the hydrogen charged sample, the non-linear elastic deformation was observed at 300 MPa in (110) planes, and then at 400 MPa in (200) planes. The microstructure observation confirmed the cleavage crack propagation and local crystal rotation in the hydrogen charged sample. Here, a concept about crystallographic orientation dependent micro-yielding was proposed, i.e. the hydrogen charging promoted the (110) preferable micro-yielding rather than (200) preferable micro-yielding, and resulted into a special deformation characteristics.

論文

Progress in bulk texture measurement using neutron diffraction

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.

論文

飛行時間法中性子回折によるバルク材料集合組織測定技術の開発

徐 平光; 星川 晃範*; 林 真琴*; 秋田 貢一; 森井 幸生*; 石垣 徹*

日本材料学会第48回X線材料強度に関するシンポジウム講演論文集, p.7 - 9, 2014/07

Time-of-flight neutron diffraction may evidently accelerate the bulk texture measurement speed through the proper combination of multiple orientations distributed neutron detectors and the simultaneous multiple diffraction peak acquisition, and only few sample rotations are needed to be carried out. In addition to the omega-axis rotatable sample changer, a dedicated omega/chi two-axis rotatable goniometer is under urgent development. It is highly expected to play an important role to evaluate the bulk texture evolution of advanced materials during thermomechanical controlling process. Though the intrinsic difference in neutron diffraction spectra from different orientations (determined by each set of Bragg angle/azimuthal angle) evidently increases the technical difficulty in rapid texture analysis, the development of Materials Analysis Using Diffraction (MAUD, developed by Luca Lutterotti, et al.) and other relevant software/programs are bringing us much convenience. Moreover, in order to increase the accessibility to neutron diffraction bulk texture measurement instruments, the various cooperative researches and the mail-in services are being planned.

論文

Transformation strain and texture evolution during diffusional phase transformation of low alloy steels studied by neutron diffraction

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 ${it in situ}$ 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 $$alpha$$-$$gamma$$-$$alpha$$ 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.

論文

Effects of gauge volume on pseudo-strain induced in strain measurement using time-of-flight neutron diffraction

鈴木 裕士; Harjo, S.; 阿部 淳; 徐 平光; 相澤 一也; 秋田 貢一

Nuclear Instruments and Methods in Physics Research A, 715, p.28 - 38, 2013/07

 被引用回数:7 パーセンタイル:34.56(Instruments & Instrumentation)

TOF法による中性子ひずみ測定において、中性子線の減衰や表面効果、ひずみ分布などの影響により発生する見かけのひずみ変化に及ぼす測定体積の影響について、焼鈍し材や塑性曲げ材のひずみ測定により検討した。測定体積内の平均ひずみは回折強度重心位置(ncog)に重みが付くため、測定体積の変化によるncog位置の移動に伴い、その重み付き平均ひずみに見かけの変化を生じることがわかった。一方、試料表面近傍のひずみ測定においては、測定体積が試料に完浴状態にない場合に、表面効果による典型的な見かけのひずみ変化が見られた。また、測定体積が試料に完浴状態にあっても、中性子線の減衰によるncog位置の変化に伴う見かけのひずみ変化が見られ、このひずみ変化は測定体積の増加に伴い大きくなることがわかった。これらの見かけのひずみ変化は、従来のモデルにビーム発散の影響を考慮することにより、正確にシミュレーションすることができた。したがって、TOF工学回折計を用いたひずみ測定シミュレーションにおいては、ビーム発散が重要なパラメータとなり得ることを明らかとした。

論文

集合組織の測定・評価法,3; 中性子回折法

鈴木 徹也*; 徐 平光

塑性と加工, 54(625), p.106 - 110, 2013/02

近年高付加価値を有する製品開発の重要性が再認識される中で、金属材料を中心とする構造用あるいは機能性素材の高性能化が重要な課題として注目されている。従来の組織制御の限界を打破するためには材料の異方性の利用と言う発想が再評価されるべきである。結晶粒形状の異方性、結晶組織形態の異方性、複合組織あるいは複合材料であればその分布状態の異方性などさまざまが考えられる。集合組織は結晶方位の分布状態の偏りであり、材料の物理的,力学的性質の異方性に大きな影響を与える。本文はここまでにX線及び電子線における集合組織の評価技術と比べて比較的新しい測定法として中性子回折の利用による集合組織の評価技術を紹介する。中性子回折は透過能力が高いという最大の特徴を生かしてこれまで不可能であった測定が可能になる潜在的な能力を秘めている。加熱冷却、圧縮引張などの周辺装置、ソフトウエア等を含め測定装置環境も整って、金属加工制御領域に対し不可欠なバルク集合組織情報が簡単に入手される。

論文

角度分散法中性子回折集合組織測定技術環境の構築と応用

徐 平光; 秋田 貢一; 鈴木 裕士; 盛合 敦

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.19 - 20, 2012/10

Though the X-ray diffraction and the electron backscattering diffraction are usually used in the texture evaluation, the neutron diffraction can directly measure the bulk textures of various materials and provide high statistical texture information for predicting the material anisotropic property thanks to the large beam spot and the high matter penetrability, and it can also help to clarify the in situ microstructure evolution under various loading/temperature environments. According to the difference in neutron beam sources, the neutron diffractometers are generally divided into the nuclear reactor-based angle-dispersive instruments and the spallation source-based time-of-flight instruments. At the Japan Research Reactor No.3 and the Japan Proton Accelerator Research Complex, the angle dispersive neutron diffractometers and the time-of-flight neutron diffractometers provide us the possibility to develop and apply the bulk texture evaluation technique to study metallic, ceramic, polymeric, and geologic crystallographic materials. In this presentation, the characteristics of single-tube and 1-demisional position- sensitive-detector angle dispersive neutron diffractometer was simply introduced and its application on the bulk texture evaluation of a magnesium alloy before and after warm press deformation is reported.

論文

中性子回折による低合金鋼拡散相変態の結晶学的考察

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。

論文

角度分散法中性子回折によるバルク材料の集合組織解析

徐 平光; 秋田 貢一; 鈴木 裕士; 盛合 敦; 鈴木 徹也*; 行武 栄太郎*

日本材料学会第46回X線材料強度に関するシンポジウム講演論文集, p.24 - 27, 2012/07

Conventional X-ray diffraction and recent electron backscattering diffraction are widely employed to investigate the surface texture information for a specific sample, but the neutron diffraction is well known to directly measure the bulk average texture information with high statistics. In order to increase the accessibility to neutron diffraction bulk texture measurement instruments, JAEA has upgraded two angle dispersive neutron diffractometer RESA-2 and MUSASI-L. In this paper, the bulk texture measurement environments based on the angle dispersive neutron diffraction were introduced, and the application research cases to the bulk texture changes during the isothermal annealing of ARBed IF steels and during the warm press deformation of a magnesium alloy were reported here to show the good texture evaluation reliability.

論文

中性子回折によるフェライト単相鋼のひずみ時効硬化異方性の検討

鈴木 徹也*; 山中 啓輔*; 石野 まゆ子*; 篠原 康浩*; 長井 健介*; 津留 英司*; 徐 平光

鉄と鋼, 98(6), p.262 - 266, 2012/06

The work-hardening characteristics of anisotropic tensile deformations and the corresponding residual strain changes of pre-strained ferritic steels without and with ageing treatment were investigated by using angle dispersive neutron diffraction and electron back-scattering diffraction. The plastic deformation along the pre-strained direction leads to evident work-hardening at the beginning stage, showing discontinuous yielding behavior. Comparably, the plastic deformation perpendicular to the pre-strained direction shows continuously yielding. The tensile and compressive residual strains were found in the $$<$$200$$>$$ and $$<$$110$$>$$ grains along the pre-strained direction, respectively. It is also found that the difference in various oriented grains after strain ageing become more evident along the pre-strained direction but smaller perpendicular to the pre-strained direction, revealing a higher work hardening capability in the former case than in the latter case.

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