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In situ diffraction characterization on microstructure evolution in austenitic stainless steel during cyclic plastic deformation and its relation to the mechanical response

熊谷 正芳*; 秋田 貢一*; 黒田 雅利*; Harjo, S.

Materials Science & Engineering A, 820, p.141582_1 - 141582_9, 2021/07

 被引用回数:0 パーセンタイル:0(Nanoscience & Nanotechnology)

In situ neutron diffraction during 250 cycles of plastic deformation was performed and the diffraction line profile analysis was performed to qualitatively evaluate the change in the microstructure of austenitic stainless steel during the cyclic deformation. The dislocation density increased with increasing number of cycles until 50 cycles but thereafter decreased. The cycle number corresponding to this maximum point differed depending on whether it was evaluated as the total dislocation density or was deconvoluted into edge and screw dislocation densities. At the initial state, edge dislocations were predominant; however, screw dislocations greatly increased at the first stage of cyclic loading. Afterwards, edge dislocations formed cell walls and screw dislocations annihilated.



生島 一樹*; 柴原 正和*; 河尻 義貴*; 沖見 優衣*; 内田 友樹*; 秋田 貢一*; 鈴木 裕士; 諸岡 聡

日本船舶海洋工学会論文集, (30), p.123 - 130, 2019/12



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:18 パーセンタイル:92.35(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.



秋田 貢一; 中谷 隼人*; 荻原 慎二*; 菖蒲 敬久; 城 鮎美*; 井川 直樹; 下条 豊

SPring-8/SACLA利用研究成果集(Research Report) (インターネット), 6(1), p.105 - 108, 2018/01



Prediction method of improved residual stress distribution by shot peening using large scale analysis method

生島 一樹*; 柴原 正和*; 西川 聡*; 古川 敬*; 秋田 貢一; 鈴木 裕士; 諸岡 聡

E-Journal of Advanced Maintenance (Internet), 9(3), p.NT87_1 - NT87_5, 2017/11

In this work, an analysis system that can analyze the modification of the residual stress distribution by peening is proposed based on IEFEM. In the proposed analysis system, IEFEM is extended to consider the dynamic effect to analyze the dynamic phenomenon with an impulsive load. The impulsive load due to the collision of shots is modeled as an equivalent load model. The equivalent load model is integrated with IEFEM considering the dynamic effect to calculate spatially and temporally random load in dynamic analyses. Using the proposed analysis system, the residual stress distribution modification by shot peening in a multi-pass welded pipe joint is predicted. The residual stress distributions obtained by the analysis are compared with those measured by X-ray diffraction (XRD), and the effect of the number of shot collisions on the change in residual stress distribution is discussed.


EBSD解析によるステンレス鋼の疲労損傷検出; EBSDパターンクオリティの適用性

黒田 雅利*; 釜谷 昌幸*; 山田 輝明*; 秋田 貢一

日本機械学会論文集(インターネット), 83(852), p.17-00072_1 - 17-00072_7, 2017/07

これまでに、電子後方散乱回折(EBSD)測定により得られる結晶方位データを解析することで得られる平均局所方位差(Averaged Local Misorientation, Mave)(Kamaya, 2009)とオーステナイト系ステンレス鋼の低サイクル疲労の損傷量との間に相関があることを報告している。ここでは、実用上の観点から、Maveと、市販ソフトウエアで得られるイメージクオリティ(Image Quality: IQ)とを比較することで、IQの疲労損傷評価に対する適用性について検討し、各パラメータの有用性と特徴を明らかにした。また、X線回折(X-Ray Diffraction: XRD)測定も実施し、得られたXRDデータとIQ値分布とを比較することで、疲労損傷の蓄積に伴うIQ値分布の変化はすべり変形によりもたらされたことを示した。


In-situ residual stress analysis during thermal cycle of a dissimilar weld joint using neutron diffraction and IEFEM

秋田 貢一; 柴原 正和*; 生島 一樹*; 西川 聡*; 古川 敬*; 鈴木 裕士; Harjo, S.; 川崎 卓郎; Vladimir, L.*

溶接学会論文集(インターネット), 35(2), p.112s - 116s, 2017/06

Residual stresses near the weld metal of the joints before and after a thermal cycle were measured using a reactor based neutron diffraction technique in room temperature. In-situ residual stress measurements were performed on the plate type sample using a pulsed neutron diffraction technique under thermal cycles. Residual stress behaviors of the samples were examined also by the idealized explicit FEM (IEFEM), which agreed well with the experimental results of the residual stress behaviors during thermal cycles. Thermal stresses were induced near the weld metal by the difference of the linear expansion coefficients of the dissimilar base metals. Since the thermal stress exceeded the yield stress of the material during the first heating process, the residual stresses near the weld metal were redistributed and a part of the residual stress was relaxed.


Study on shot peened residual stress distribution under cyclic loading by numerical analysis

生島 一樹*; 木谷 悠二*; 柴原 正和*; 西川 聡*; 古川 敬*; 秋田 貢一; 鈴木 裕士; 諸岡 聡

溶接学会論文集(インターネット), 35(2), p.75s - 79s, 2017/06

In this research, to investigate the effect of shot peening on operation, an analysis method to predict the behavior of stress distribution on shot peening was proposed. In the proposed system, the load distribution on the collision of shots was modeled, and it was integrated with the dynamic analysis method based on the Idealized explicit FEM (IEFEM). The thermal elastic plastic analysis method using IEFEM was applied to the analysis of residual stress distribution of multi-pass welded pipe joint. The computed residual stress distribution was compared with the measured residual stress distribution using X-ray diffraction (XRD). As a result, it was shown that the both welding residual stress distribution agree well with each other. Considering the computed welding residual stress distribution, the modification of stress distribution due to shot peening was predicted by the proposed analysis system.



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.


Numerical analysis of residual stress distribution on peening process

生島 一樹*; 柴原 正和*; 秋田 貢一; 鈴木 裕士; 諸岡 聡; 西川 聡*; 古川 敬*

Welding in the World, 61(3), p.517 - 527, 2017/05



Hydrostatic compression behavior and high-pressure stabilized $$beta$$-phase in $$gamma$$-based titanium aluminide intermetallics

Liss, K.-D.*; 舟越 賢一*; Dippenaar, R. J.*; 肥後 祐司*; 城 鮎美*; Reid, M.*; 鈴木 裕士; 菖蒲 敬久; 秋田 貢一

Metals, 6(7), p.165_1 - 165_22, 2016/07

 被引用回数:16 パーセンタイル:72.33(Materials Science, Multidisciplinary)



Local structure of room-temperature superionic Ag-GeSe$$_3$$ glasses

Stellhorn, J. R.*; 細川 伸也*; 川北 至信; Gies, D.*; Pilgrim, W.-C.*; 林 好一*; 大山 研二*; Blanc, N.*; Boudet, N.*

Journal of Non-Crystalline Solids, 431, p.68 - 71, 2016/01

 被引用回数:6 パーセンタイル:38.86(Materials Science, Ceramics)

Anomalous X-ray scattering experiments on amorphous Ag$$_{0.5}$$(GeSe$$_{3}$$)$$_{0.5}$$ at the K absorption edges of each constituent element has been performed to investigate the local- and intermediate-range structure in this material. This method can provide insight into the structural properties enabling the effect of superionic conductivity in the amorphous phase. The experimental results were analyzed with reverse Monte Carlo modeling, providing the partial structure factors and the corresponding partial pair-distribution functions. A nanometer range phase separation tendency of the Ag atoms over a background of a GeSe$$_4$$ tetrahedral network is observed, which may confirm the view of Ag conduction pathways forming in this phase.


Non-destructive damage assessment in CFRP/Ti laminates by synchrotron radiation laminography

中谷 隼人*; 梶原 堅太郎*; 秋田 貢一; 荻原 慎二*

Proceedings of 14th Japan International SAMPE Symposium & Exhibition (JISSE-14) (USB Flash Drive), 6 Pages, 2015/12

Synchrotron radiation laminography at SPring-8 is employed to assess low velocity impact damage in CFRP/Ti laminates as one of the most interested Fibre-Metal Laminates (FMLs). During computed laminography bright X-ray is irradiated to an object with the axis of rotation inclined at an angle and thus it is suitable for the laterally extended geometry of composite laminate plates. It is confirmed how each damage mode in the CFRP/Ti laminates can be imaged by synchrotron radiation laminography by using model specimens that contain artificially induced damage. Then 3-dimensional imaging of impact-induced damage where each damage mode shows complex distribution is demonstrated and that is to our knowledge a novel result.


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.


Internal stress distribution for generating closure domains in laser-irradiated Fe-3%Si(110) steels

岩田 圭司*; 今福 宗行*; 鈴木 環輝*; 菖蒲 敬久; 折原 秀人*; 酒井 祐介*; 秋田 貢一; 大谷 眞一*; 石山 和志*

Journal of Applied Physics, 117(17), p.17A910_1 - 17A910_4, 2015/03

 被引用回数:5 パーセンタイル:27.89(Physics, Applied)



X-ray line profile study on shot/laser-peened stainless steel

熊谷 正芳*; 秋田 貢一; 今福 宗行*; 大谷 眞一*

Advanced Materials Research, 996, p.39 - 44, 2014/08

 被引用回数:4 パーセンタイル:92.01



Relaxation behavior of laser-peening residual stress under tensile loading investigated by X-ray and neutron diffraction

秋田 貢一; 林 健吾*; 竹田 和也*; 佐野 雄二*; 鈴木 裕士; 盛合 敦; 大谷 眞一*

Mechanical Engineering Journal (Internet), 1(4), p.SMM0029_1 - SMM0029_8, 2014/08

ピーニング技術による圧縮残留応力の導入は、疲労や応力腐食割れ等の鋼の強度特性の改善に有効である。ただし、圧縮残留応力は稼働時に機器に作用する熱的あるいは機械的な外力が原因で低下する可能性がある。本研究では、レーザーピーニングを施したフェライト鋼の静的引張荷重下における表面及び内部の残留応力挙動を、X線および中性子回折によって検討した。X線回折および中性子回折の相補利用により、応力緩和プロセスを明確に示す実験的確証が得られた。また、引張負荷応力下における臨界負荷応力の値は、内部の最大引張残留応力値とvon Misesの降伏条件によって推定できることを示した。



秋田 貢一

検査技術, 19(7), p.62 - 66, 2014/07



Workhardening and the microstructural characteristics of shot- and laser-peened austenitic stainless steel

熊谷 正芳*; 秋田 貢一; 今福 宗行*; 大谷 眞一*

Materials Science & Engineering A, 608, p.21 - 24, 2014/07

 被引用回数:8 パーセンタイル:46.14(Nanoscience & Nanotechnology)




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.

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