| 研究課題/領域番号 |
20K20106
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| 研究機関 | 国立研究開発法人日本原子力研究開発機構 |
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研究代表者 |
蘇 玉華 国立研究開発法人日本原子力研究開発機構, 原子力科学研究部門 J－PARCセンター, 主査 (20644264)
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| 研究期間 (年度) |
2020-04-01 – 2022-03-31
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| キーワード | fatigue damage / Bragg-edge imaging / neutron diffraction |
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| 研究実績の概要 |
This research is devoted to develop the fatigue evaluation technique by a combination of two neutron methods: Bragg-edge transmission imaging and diffraction. Here, we prepared the compact-tension (CT) specimens under different fatigue conditions. Two kinds of steels: an austenitic stainless steel (SUS304) and a duplex stainless steel (SUS329J4L; Japanese Industrial Standards) consisting of austenite and ferrite, were used in the present investigation. The two-dimensional (2D) maps of the residual strain/stress and microstructure around a fatigue crack can be non-destructively obtained by Bragg-edge spectral analysis and diffraction pattern analysis.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
The fatigue crack growth tests were conducted using constant-amplitude cyclic loading model at room temperature until the crack length reached 10 mm or 25 mm. In addition, the digital image correlation (DIC) was also applied for crack tip strain field characterisation at the surface of the samples during the fatigue testing. We have performed the time-of-flight (TOF) neutron Bragg-edge transmission imaging experiment at the energy-resolved neutron imaging system, RADEN, BL22 and the neutron diffraction experiment at the engineering diffractometer, TAKUMI, BL19 at MLF/J-PARC, respectively.
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| 今後の研究の推進方策 |
The RITS code will be used for Bragg-edge spectral analysis. 2D maps of the strain, texture variations and phase volume fraction can be obtained. The diffraction data will be analysed by the Z-Rietveld software, to obtain residual lattice strain, texture and phase volume fractions. The obtained original information of the strain and crystalline structure state inside the bulk could give a greater understanding on crack tip elastic and plastic strain evolution mechanisms in engineering materials. The 2D mapping technique will be further applied to investigate the effect of temperature on the fatigue-crack growth behaviours, to evaluate how the martensite distribution due to phase transformation under cryogenic conditions of very low temperature to affect the fatigue-crack growth.
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| 次年度使用額が生じた理由 |
The incurring amount will be used for sample and jig preparations, academic conference participations and paper publications in the next fiscal year.
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