実験報告書様式（一般利用課題・成果公開利用）

MLF Experimental Report

提出日 Date of Report
July 23, 2010

課題番号 Project No.

装置責任者 Name of responsible person

2009B0027

Toru Ishigaki

実験課題名 Title of experiment

装置名 Name of Instrument/（BL No.）

Study on preferred orientation analysis with the comparison ofBL20 iMATERIA

the diffraction and transmission measurements

実施日 Date of Experiment

実験責任者名 Name of principal investigator

May 25-26, 2010

Takashi Kamiyama
所属 Affiliation
Graduate School of Engineering, Hokkaido University
試料、実験方法、利用の結果得られた主なデータ、考察、結論等を、記述して下さい。（適宜、図表添付のこと）
Please report your samples, experimental method and results, discussion and conclusions. Please add figures andtables for better explanation.
1. 試料 Name of sample(s) and chemical formula, or compositions including physical form.
1. Welded α-Fe (ferrite), called the non-textured specimen in this report.
Low-carbon steel (Fe-0.15wt%C)
Solid polycrystalline metal
2. Rolled α-Fe (ferrite), called the soft-textured specimen in this report.
Low-carbon steel (Fe-0.15wt%C)
Solid polycrystalline metal
3. Textured α-Fe (ferrite), called the hard-textured specimen in this report.
Low-carbon steel (Fe-0.15wt%C)
Solid polycrystalline metal

2. 実験方法及び結果 （実験がうまくいかなかった場合、その理由を記述してください。）
Experimental method and results.

If you failed to conduct experiment as planned, please describe reasons.

2.1. Aim
We have been developing Bragg edge transmission imaging techniques at a pulsed neutron source forcrystallographic visualization of crystal structure, crystalline phase, crystallographic texture, microstructureand strain. In particular, the bulk information of texture and microstructure is very important for developmentof high-performance structural and functional materials in terms of the strength, the formability and theelectromagnetic property. For this reason, we developed the Bragg edge transmission imaging method with theRietveld-type refinement analysis technique, based on an original computer program “RITS”. So far, theneutron imaging based on the RITS code has succesfully visualized the spatial distributions of the degree ofcrystallographic anisotropy caused by preferred orientation of textures, the preferred orientation axis that isparallel to a certain direction of a specimen, and the crystallite size where the extinction effect of diffractedneutrons occurs. However, neutron diffraction studies for verification of this new neutron imaging technique12. 実験方法及び結果（つづき） Experimental method and results (continued)
have not been performed yet. Hence, we measured the time-of-flight neutron diffraction data of some
textured specimens that have been already measured by the Bragg edge transmission imaging. Then, wecompared each other the results given by both the transmission imaging and the diffraction.
2.2. Experimental
We carried out neutron diffraction experiments at BL20 “iMATERIA” at MLF in J-PARC. The measured
specimens were the three-kind polycrystalline α-Fe; a non-textured metal that was welded, a soft-textured
metal that was rolled, and a hard-textured metal that was re-crystallized. We measured a non-rotatedspecimen (a textured specimen) and a rotated specimen (a pseudo non-textured specimen in theDebye-Scherrer geometry) with respect to each metal. Thus, we compared the six-kind diffraction data.
2.3. Results and discussion
Fig. 1 shows the neutron diffraction results. The consistent points between the transmission imaging and thediffraction are summarized that:(1) The Bragg peaks of {111} equivalent group and also {211} equivalent group (that are the preferredorientation axis along “the normal direction” of α-Fe) of the soft-texture are larger than ones of thenon-texture. Furthermore, ones of the hard-texture are additionally larger than ones of the soft-texture.
(2) Only {110} Bragg peak of the soft-texture is smaller than one of the non-texture. This is due to theextinction effect of larger crystallites of the soft-textured metal.
Furthermore, the interesting results are that:(1) The peaks of the non-texture that has smaller crystallites according to the Bragg edge transmission
imaging with the extinction analysis are broader than ones of the soft-texture that has larger crystallites
according to the Bragg edge transmission imaging with the extinction analysis. According to the Scherrer’sequation, the peak broadening indicates that the crystallite size becomes small. Namely, the broadening of thediffraction peak is clearly consistent with the extinction of the Bragg edge transmission.
(2) The peak intensities of only the hard-texture are changed by a sample rotating that makes a pseudo
non-textured specimen.
2.4. Conclusion and future works
A part of the validity of the Bragg edge transmission imaging was confirmed by neutron diffraction studies. In
near future, we will try to compare the Rietveld refinement results of transmission imaging (RITS developed by100{310}

Weld
Rotated weld
Roll
Rotated roll
TextureRotated texture{200}

20{222}40{330}60{220}

{321}

{211}

80{431}

Neutron intensity / arb. unit

120{110}

Hokkaido University) and diffraction (Z-Rietveld developed by J-PARC).

05

1015

202530

Neutron flight time / msecFig. 1: Neutron time-of-flight diffraction data of some textured α-Fe metals.
2