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 31, 2017

課題番号 Project No.

装置責任者 Name of responsible person

2017A0214

Stefanus Harjo

実験課題名 Title of experiment

装置名 Name of Instrument/（BL No.）

Through-thickness distribution of residual stresses in a part

TAKUMI/ BL 19

produced by additive manufacturing

実施日 Date of Experiment

実験責任者名 Name of principal investigator

May 28-30, 2017

NANAMI, Norimichi
所属 Affiliation
Nihon 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.
[Name of sample]
An additive manufacturing sample of aluminum AiSi10Mg[Material composition]
Al (balance), Si (9.0 - 11.0 wt%), Fe (≤ 0.55 wt%), Cu (≤ 0.05 wt%), Mn (≤ 0.45 wt%), Mg (0.2 - 0.45 wt%),
Ni (≤ 0.05 wt%), Zn (≤ 0.10 wt%), Pb (≤ 0.05 wt%), Sn (≤. 0.05 wt%), Ti (≤ 0.15 wt%)

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.

The residual stress measurements of the additive manufacturing (AM) sample that had 20 mm in diameterand 10 mm in height were conducted with the engineering materials diffractometer (BL19 TAKUMI). The
particular environmental conditions were not applied for measurements (i.e., at room temperature and underatmospheric pressure). The measurement locations of the AM sample are presented in Figure 1. Seven locationsin the in-plane direction and three locations in the through-thickness direction were chosen, totaling to 21
locations in the AM sample. The gage volume of the measurements was 1.5 mm x 1.5 mm x 1 mm. It should be
noted that two measurements be conducted at the location, the distances of 8, 9, 10 mm measured from the centerof the AM center due to the size of the gage volume. For the axial residual stress measurements, the sample wasrotated about the hoop-axis at 90° using the Eurelian cradle, and it was irradiated with neutron beams. Neutron
diffraction patterns were measured using a time-of-flight method, and the crystal structure analysis of theobtained experimental data was performed on the software, Z-Rietveld, developed by the High Energy
Accelerator Research Organization. Lattice strains per measurement location were calculated, and thethree-dimensional residual stress field of the sample was found. It should be noted that the unstressed lattice12. 実験方法及び結果（つづき） Experimental method and results (continued)
spacing be determined by measuring the lattice spacing of the sample where eight 1.5 mm cubes taken from anAM sample were randomly arranged.
The normalized radial, hoop, and axial residual stress distributions in the vicinity of the top face of the AM
sample are presented in Figures 2-4, respectively. Note that the normalized stress is defined as a stress on alocation over the maximum compressive stress. It was presented that the stress fields at all measurement
locations were in compression. The maximum radial and hoop stresses were 2.4 times and 1.5 times as high as
the maximum axial stress, respectively. It is seen in Figure 3 that the maximum and minimum values of the radialstresses respectively occur at the distances of 10 mm and 5 mm from the center of the sample. Figure 4 showsthat the highest hoop stress is presented in the vicinity of the side of the AM sample while the smallest stress is at
the distance of 7 mm measured from the center of the sample. It is observed in Figure 5 that the axial stressdecreases as moving away from the center of the sample. In typical casting alloys, the outer region of a part is incompression while the inner region of a part is in tension. Since the local region of the sample was melted andsolidified in a very short time during the AM process, it was obtained that the residual stress distribution of theAM sample was different to that of a casting part.
Further investigation to understand the three-dimensional map of residual stresses in the AM sample has
been being performed. In parallel, hardness tests of the AM samples are being conducted to define therelationship between hardness and residual stress of AM products.

Figure 1. Measurement locations of the AM sample in mm.

Figure 2. Normalized radial stress distribution on the top.

Figure 3. Normalized hoop stress distribution on the top.

Figure 4. Normalized axial stress distribution on the top.

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