実験報告書様式（一般利用課題・成果公開利用）（ ※本報告書は英語で記述してください。ただし、産業利用課題として採択されている方は日本語で記述していただいても結構です。 ）MLF Experimental Report

提出日 Date of Report
2018/1/19

課題番号 Project No.

装置責任者 Name of responsible person

2017B0106

Takenao Shinohara

実験課題名 Title of experiment

装置名 Name of Instrument/（BL No.）

Imaging of hydrogen localized in aluminium

BL22

実験責任者名 Name of principal investigator

実施日 Date of Experiment

Hiroyuki Toda

2017/11/20-21

所属 Affiliation
Department of mechanical engineering, Kyushu 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.
4N pure aluminum
Al-10%Zn-1%Mg alloy
3N pure Palladium

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.

Experimental methods
Neutron transmission imaging was performed in order to visualize the hydrogen distribution in
the metal. The experiment was conducted at BL22 RADEN. L/D value was set to 230, and neutronenergies were tuned to 2-3 Å and 5-13.5 Å by the disc chopper. Cooled CCD (2k x 2k pixels) andZnS / 6LiF scintillator were used for the detector, and the field of view was 30 x 30 mm. Specimensarepurealuminum,Al-Zn-Mg

alloy,andpurepalladium.

Hydrogen-chargedandhydrogen-uncharged specimens were used to the imaging.
Results
Fig. 1 shows the neutron transmission images of wavelengths (a) 2-3 Å and (b) 5-13.5 Å. The
contrast of the image is normalized by the direct beam and corresponds to the neutrontransmittance. In the palladium after hydrogen charging, the contrast changed darkly from theedge of the specimen toward the center.
12. 実験方法及び結果（つづき） Experimental method and results (continued)
This change in contrast means a decrease in neutron transmittance, which suggests that thehydrogen content inside the specimen is high. It has been considered that hydrogen near thesurface was desorbed before imaging.
On the other hand, contrast change with and without hydrogen is limited in the aluminum. This isdue to aluminum has a significantly low equilibrium hydrogen solubility compared withpalladium. The attenuation coefficients of aluminum were evaluated using the average
wavelength from Fig. 1. As a result, the change of attenuation coefficients is corresponding to thedifference in the wavelength range. Furthermore, when estimating the hydrogen content from theattenuation coefficients, the hydrogen content in aluminum evaluated from two imaging was bothon the order of mass ppm. Fig. 2 shows the results of thermal desorption analysis of thehydrogen-charged aluminum. Solute hydrogen was the order of mass ppm. It has been reasonably
inferred that the slight contrast change of aluminum with and without hydrogen in Fig.1 is theinfluence by hydrogen.
Thus, hydrogen was detected in both palladium and aluminum in the present neutron imaging.
The author plan to extend to tomographic observation and aim at visualization of 3D hydrogen
distribution in the further works.

H desorption rate (mass-ppm/min)Fig. 1 Neutron transmission images at wavelength ranged (a) 2-3 Å and (b) 5-13.5 Å0.030
H charged Al

0.025
0.020
0.015
0.010
0.005
0.000

100

200300400500

Temperature, T / oC

Fig. 2 Hydrogen desorption curve of hydrogen charged aluminum2