| 研究課題/領域番号 |
16K17981
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| 研究機関 | 九州大学 |
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研究代表者 |
マカドレ アルノー 九州大学, カーボンニュートラル・エネルギー国際研究所, 学術研究員 (20635891)
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| 研究期間 (年度) |
2016-04-01 – 2018-03-31
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| キーワード | hydrogen embrittlement / austenite / grain refinement |
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| 研究実績の概要 |
By producing different grain sizes of austenite (from 1 micron to 21 microns grains), I have shown how hydrogen influences the tensile properties of metastable austenite under tensile loading.
After exposure to 10 MPa hydrogen gas, metastable austenite does not suffer large effects of hydrogen for grain sizes below 6 microns. The ductility of small austenitic grains is only slightly reduced and the fracture remains fully ductile. Larger grains suffer from significant ductility reduction and display embrittled fracture (quasi-cleavage and intergranular).
The increased resistance of fine austenitic grains against hydrogen embrittlement is explained by the limited dislocation pile-up distance within grains as well as uniform distribution of stress and deformation in small grains.
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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 heat treatments and hydrogen exposure for grain size and hydrogen content control are all successful, thanks to good procedure control.
A new testing method (in-situ SEM tensile testing) gives precious information for the fracture mechanism.
Both fracture surface analysis and microstructure analysis are yielding reliable data enabling connections between grain size, hydrogen content and fracture.
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| 今後の研究の推進方策 |
Grain boundary analysis is necessary, both with and without hydrogen, under loading, to understand how dislocations interact with hydrogen and grain boundaries, inclusions and martensite-austenite boundaries.
This will be done with EBSD. Dislocation observation would be done with TEM.
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| 次年度使用額が生じた理由 |
The received amount in the first year was not enough to buy the necessary rolling mill
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| 次年度使用額の使用計画 |
With the added amount of both years, the necessary rolling mill will be purchased.
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