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In-house texture measurement using a compact neutron source

徐 平光; 池田 義雅*; 箱山 智之*; 高村 正人*; 大竹 淑恵*; 鈴木 裕士

Journal of Applied Crystallography, 53(2), p.444 - 454, 2020/04

 被引用回数:0 パーセンタイル:100(Chemistry, Multidisciplinary)

In order to improve the instrumental accessibility of neutron diffraction technique, the emerging compact neutron sources and in-house neutron diffractometers as a good complementary way have caused wide attention while their analysis precision seems problematic for the practical application. As a challenging project, the RIKEN accelerator-driven compact neutron source (RANS) was employed to establish the technical environment for texture measurement, and the recalculated pole figures and the orientation distribution function (ODF) of an interstitial-free (IF) steel sheet obtained from RANS were compared with the results from another two neutron diffractometers well-established for texture measurement. Moreover, the parameter "square integration of ODF difference" originally for evaluating the numerical error between the measured and simulated textures was generalized here to examine the reliability of RANS texture measurement. These quantitative comparisons revealed that the precise neutron diffraction texture measurement at RANS has been realized successfully and the following technical optimizations are much valuable, including the thickness selection of polyethylene moderator, the sample-to-detector distance, the B$$_{4}$$C shielding sheets for the reduced background noise, and the fine region division of the neutron detector panel. Moreover, the Rietveld texture analysis improves the texture reliability through avoiding the unfavorable influence of the uncertain diffraction intensity involved in the low counting, long wavelength incident neutrons at large scattering angles. Above technical results may accelerate the development of other easily accessible engineering materials evaluation techniques using compact neutron source, and also help to improve the data-collecting efficiency for various time-sliced scattering experiments at large neutron facilities.


Convergence behavior in line profile analysis using convolutional multiple whole-profile software

熊谷 正芳*; 内田 知宏*; 村澤 皓大*; 高村 正人*; 池田 義雅*; 鈴木 裕士; 大竹 淑恵*; 浜 孝之*; 鈴木 進補*

Materials Research Proceedings, Vol.6, p.57 - 62, 2018/10

 被引用回数:0 パーセンタイル:100

The convergence behavior of the parameters related to microstructural characteristics $$a$$-$$e$$ was studied during optimizations in a common line profile analysis software program based on the convolutional multiple whole profile (CMWP) method. The weighted sums of squared residual (WSSR) was a criterion of the optimization. The parameters $$b$$ and $$d$$, which are related to the dislocation density and to the crystallite size, respectively, strongly affect the line profile shape. Therefore, the distributions of WSSRs on the space parameters $$b$$ and $$d$$ were first observed. The variation trajectory of parameters $$b$$ and $$d$$ during iterative calculations with several values of parameter $$e$$ was then observed, along with the variations when all of the parameters were variable. In the case where only three parameters were variable, we found that a smaller initial value of $$e$$ should be chosen to ensure stability of the calculations. In the case where all parameters were variable, although all of the results converged to similar values, they did not precisely agree. To attain accurate optimum values, a two-step procedure is recommended.


Determination approach of dislocation density and crystallite size using a convolutional multiple whole profile software

村澤 皓大*; 高村 正人*; 熊谷 正芳*; 池田 義雅*; 鈴木 裕士; 大竹 淑恵*; 浜 孝之*; 鈴木 進補*

Materials Transactions, 59(7), p.1135 - 1141, 2018/07

 被引用回数:5 パーセンタイル:42.66(Materials Science, Multidisciplinary)

Neutron diffraction profile analysis using the whole profile fitting method is useful for obtaining microscopic information on metallic materials. To determine an appropriate fitting approach for obtaining reasonable and non-arbitrary results, we applied diffraction line profile analyses using the Convolutional Multiple Whole Profile (CMWP) method to diffraction patterns obtained using the Engineering Materials Diffractometer (TAKUMI, BL19) at the Materials and Life Science Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC). The tensile specimens of 780 MPa grade bainitic steel were uniaxially stretched until the plastic strain reached a value of 0.05. We performed CMWP analyses on the obtained diffraction patterns during tensile test with various initial parameters of dislocation density and crystallite size. These parameters were optimized in the fitting procedures to minimize the weighted sums of squared residuals (WSSRs). Following this approach, we found that unsuitable initial parameter values resulted in unreasonable convergence. Therefore, initial fitting parameters should be chosen to ensure that the initial profiles are as broad as possible. Reasonable results were obtained following this suggestive approach even when the strain anisotropy parameter is set to arbitrary values.



池田 義雅*; 高村 正人*; 箱山 智之*; 大竹 淑恵*; 熊谷 正芳*; 鈴木 裕士

鉄と鋼, 104(3), p.138 - 144, 2018/03

 被引用回数:1 パーセンタイル:82.98(Metallurgy & Metallurgical Engineering)



Prospect for application of compact accelerator-based neutron source to neutron engineering diffraction

池田 義雅*; 竹谷 篤*; 高村 正人*; 須長 秀行*; 熊谷 正芳*; 大場 洋次郎*; 大竹 淑恵*; 鈴木 裕士

Nuclear Instruments and Methods in Physics Research A, 833, p.61 - 67, 2016/10

 被引用回数:22 パーセンタイル:2.8(Instruments & Instrumentation)



Texture evaluation in ductile fracture process by neutron diffraction measurement

須長 秀行*; 高村 正人*; 池田 義雅*; 大竹 淑恵*; 浜 孝之*; 熊谷 正芳*; 鈴木 裕士; 鈴木 進補*

Journal of Physics; Conference Series, 734(Part B), p.032027_1 - 032027_4, 2016/09

 被引用回数:0 パーセンタイル:100



Non-destructive texture measurement of steel sheets with compact neutron source "RANS"

高村 正人*; 池田 義雅*; 須長 秀行*; 竹谷 篤*; 大竹 淑恵*; 鈴木 裕士; 熊谷 正芳*; 浜 孝之*; 大場 洋次郎*

Journal of Physics; Conference Series, 734(Part B), p.032047_1 - 032047_4, 2016/08

 被引用回数:2 パーセンタイル:24.4



Identified charged hadron production in $$p + p$$ collisions at $$sqrt{s}$$ = 200 and 62.4 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; 秋葉 康之*; Al-Bataineh, H.*; Alexander, J.*; 青木 和也*; Aphecetche, L.*; Armendariz, R.*; et al.

Physical Review C, 83(6), p.064903_1 - 064903_29, 2011/06

 被引用回数:142 パーセンタイル:0.63(Physics, Nuclear)

200GeVと62.4GeVでの陽子陽子の中心衝突からの$$pi, K, p$$の横運動量分布及び収量をRHICのPHENIX実験によって測定した。それぞれエネルギーでの逆スロープパラメーター、平均横運動量及び単位rapidityあたりの収量を求め、異なるエネルギーでの他の測定結果と比較する。また$$m_T$$$$x_T$$スケーリングのようなスケーリングについて示して陽子陽子衝突における粒子生成メカニズムについて議論する。さらに測定したスペクトルを二次の摂動QCDの計算と比較する。


Azimuthal correlations of electrons from heavy-flavor decay with hadrons in $$p+p$$ and Au+Au collisions at $$sqrt{s_{NN}}$$ = 200 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; 秋葉 康之*; Al-Bataineh, H.*; Alexander, J.*; 青木 和也*; Aphecetche, L.*; Aramaki, Y.*; et al.

Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04

 被引用回数:8 パーセンタイル:49.68(Physics, Nuclear)




徐 平光; 高村 正人*; 池田 義雅*; 角田 龍之介*; 高橋 進*; 箱山 智之*; 岩本 ちひろ*; 大竹 淑恵*; 鈴木 裕士

no journal, , 

自動車の軽量化のために使用されている高張力薄鋼板は、プレス成形による加工性が低いことから、生産不良が多い。そのため、プレス成形性を向上させる手段の一つとして、鋼材の集合組織制御に期待が寄せられている。実用に供される金属材料の微視組織は不均一な集合組織を有している。圧延板の加工性など金属材料のマクロな特性を議論する際には、金属材料のバルク平均の集合組織を考慮することが適切だと考えられる。中性子線を用いた集合組織測定は、高い透過性と大きなゲージ体積という特徴を生かして、加工性に直結する金属材料のバルク平均情報を容易に測定することができる。しかしながら、日本国内に限らず、世界中には、集合組織が測定できる中性子回折装置が極めて少ない。そこで、我々は研究用原子炉施設(JRR-3)の定常中性子源と大強度陽子加速器施設(J-PARC)のパルス中性子源を用いた集合組織測定技術を確立し、世界トップレベルの測定精度を有する集合組織測定装置を開発した。近年、中性子評価技術をより広く普及するため、理化学研究所が"いつでも、どこでも、手軽に利用できる"をキャッチフレーズとした小型中性子源(RANS)の開発を進めており、我々がこれまでに培ってきたノウハウを最大限に生かして、RANSを用いた粉末回折技術や集合組織測定技術の開発に挑戦してきた。本発表では、JRR-3, J-PARCおよびRANSで開発した鉄鋼材料の集合組織測定技術を簡単に紹介するとともに、中性子回折による集合組織測定研究に関して大型中性子施設と小型中性子源との連携案について議論する。


Neutron diffraction with RANS for industrial "on-site" applications

高村 正人*; 岩本 ちひろ*; 徐 平光; 角田 龍之介*; 栗原 諒*; 箱山 智之*; 池田 義雅*; 鈴木 裕士; 大竹 淑恵*

no journal, , 

High strength steels are becoming more and more important in automotive body structures for good weight reduction, providing further requirement in the balance between strength and formability. Numerical models in forming simulations taking into account the texture evolution may accurately analyze macroscopic plastic behavior, through referring to local surface texture measurement using Electron backscatter diffraction or X-ray diffraction. In contrast, neutron diffraction may measure the microstructure factors including bulk-averaged texture, enable to more deeply understand the mechanisms of deformation behavior. Such neutron diffraction studies usually require large-scale experimental facilities like a reactor and a large accelerator, so meet certain difficulty in the instrumental accessibility. To solve these problems, Riken Accelerator-driven Compact Neutron Source (RANS) has been developed. On-site evaluation of microstructural factors enables us to analyze metal deformation processes more efficiently. Authors have recently succeeded in accurately measuring the texture evolution of an IF steel and also in determining the retained austenite volume fraction of multi-phase steels, by optimizing the beam condition and layout of collimators, samples, detectors, etc. These results show the possibility of practical use of an in-house compact neutron source in laboratories of universities, research institutes and industrial firms.

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