Analysis and mapping of detailed inner information of crystalline grain by wavelength-resolved neutron transmission imaging with individual Bragg-dip profile-fitting analysis

櫻井 洋亮*; 佐藤 博隆*; 足立 望*; 諸岡 聡; 戸高 義一*; 加美山 隆*

Applied Sciences (Internet), 11(11), p.5219_1 - 5219_17, 2021/06

https://doi.org/10.3390/app11115219

As a new method for evaluating single crystal and oligocrystal, pulsed neutron Bragg-dip transmission analysis/imaging method is being developed. In this study, a single Bragg-dip profile fitting analysis method was newly developed, and applied for analyzing detailed inner information in a crystalline grain position-dependently. In the method, the spectrum profile of a single Bragg-dip is analyzed at each position over a grain. As a result, it is expected that changes of crystal orientation, mosaic spread angle and thickness of a perfect crystal can be evaluated from the wavelength, the width and the integrated intensity of the Bragg-dip, respectively. For confirming this effectiveness, the method was applied to experimental data of position-dependent Bragg-dip transmission spectra of a Si-steel plate consisting of oligocrystals. As a result, inner information of multiple crystalline grains could be visualized and evaluated. The small change of crystal orientation in a grain, about 0.4, could be observed by imaging the Bragg-dip wavelengths. By imaging the Bragg-dip widths, both another grain and mosaic block in a grain were detected. Furthermore, imaging results of the integrated intensities of Bragg-dips were consistent with the results of Bragg-dip width imaging. These small crystallographic changes have not been observed and visualized by previous Bragg-dip analysis methods.

Composite behavior of lath martensite steels induced by plastic strain, a new paradigm for the elastic-plastic response of martensitic steels

Ungr, T.*; Harjo, S.; 川崎 卓郎; 友田 陽*; Ribrik, G.*; Shi, Z.*

Metallurgical and Materials Transactions A, 48(1), p.159 - 167, 2017/01

AA2016-0372.pdf:2.81MB

https://doi.org/10.1007/s11661-016-3845-4

Based on high-resolution neutron diffraction experiments we will show that in lath martensite steels the initially homogeneous dislocation structure is disrupted by plastic deformation, to produce a composite on the length scale of martensite lath packets. The diffraction patterns of plastically strained martensitic steel reveal characteristically asymmetric peak profiles in the same way as has been observed in materials with heterogeneous dislocation structures. Lath packets oriented favorably or unfavorably for dislocation glide become soft or hard. The lath packet type develops by work softening or work hardening in which the dislocation density becomes smaller or larger compared to the initial average one. The decomposition into soft and hard lath packets is accompanied by load redistribution between the two lath packet types. The composite behavior of plastically deformed lath martensite opens a new way to understand the elastic-plastic response in this class of materials.

Evaluation of ductile damage progress of aluminum single crystal with prior activity of single slip system under tensile loading by using synchrotron white X-ray

柴野 純一*; 梶原 堅太郎*; 塚本 拓也*; 河合 紘和*; 三浦 節男*; Zhang, S.*; 菖蒲 敬久; 小林 道明*

Materials Science Forum, 777, p.176 - 181, 2014/02

https://doi.org/10.4028/www.scientific.net/MSF.777.176

A ductile damage progress of an aluminum single crystal with the prior activity of the single slip system under tensile loading was verified by a profile analysis using white X-ray obtained in BL28B2 beam line of SPring-8. In this study, the aluminum single crystal of the purity 6N was used as a specimen prepared in I-type geometry for tensile test. In profile analysis, an instrumental function was defined in consideration both of a divergence by a slit and a response function peculiar to the energy dispersive method. The Gauss component of integral breadth related to non-uniform strain and the Cauchy component of integral breadth related to crystallite size were determined by eliminating the broadening by the instrumental function from the diffraction profile of white X-ray. As a result, the characteristics of ductile damage progress near the notch of the aluminum single crystal were inspected from the distribution of both non-uniform strain and dislocation density.

Analysis of the asymmetric 002 X-ray line profiles of -irradiated polyethylene

依田 修; 小田島 晟*

Japanese Journal of Applied Physics, 19(7), p.1241 - 1245, 1980/00

https://doi.org/10.1143/JJAP.19.1241

非対称X線回折線プロフィルの解析を行い、非対称性は、プロフィルの反射次数が低く、格子歪がプロフィルの幅を広げる効果があまり顕著でない場合には、微結晶のサイズと格子面間隔の間に一定の相関があるために現れることを見出した。線を大量に照射したポリエチレンの002プロフィルに応用し、サイズと両間隔の相関を明らかにして、線によるポリエチレン結晶の崩壊機構を明らかにした。

Molecular motion and structure of unsintered polytetrafluoroethylene, 3; Texture from the measurement of 100 Debye-Scherrer line profiles

依田 修; 田村 直幸

Reports on Progress in Polymer Physics in Japan, 16, p.231 - 234, 1973/00

未焼成ポリテトラフルオルエチレンのラテラル方向の微結晶サイズと格子歪を、100デバイーシェラー線を測定することによって調べた。その結果(1)乳化重合PTFEに懸濁重合物よりも結晶サイズは大きく、また分子鎖のパッキングはより密である。(2)機械的処理によって微結晶はより小さくなり、格子歪は増大すると共に、非晶成分が現われる。(3)焼成によってポリマー分子鎖は再配列を起し、格子の欠陥部分は結晶外に押し出されることにより結晶サイズが増大すると共に歪は減少する。(4)50MRまでの線照射では結晶サイズ、格子歪共に顕著な変化は見出されないことがわかった。

Interpretation of line profiles by the Fourier method, with special reference to the size distribution of carbon black crystallites

土井 健治

Acta Crystallographica, 14(8), p.830 - 834, 1961/00

https://doi.org/10.1107/S0365110X61002424

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