| 研究課題/領域番号 |
16F16809
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| 研究機関 | 九州大学 |
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研究代表者 |
陳 強 九州大学, 工学研究院, 教授 (30264451)
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| 研究分担者 |
HE CHAO 九州大学, 工学(系)研究科(研究院), 外国人特別研究員
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| 研究期間 (年度) |
2016-11-07 – 2019-03-31
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| キーワード | Very High Cycle Fatigue / Magnesium Alloys / LPSO Phase / Ultrasonic fatigue |
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| 研究実績の概要 |
Fatigue behavior and fracture mechanism of Mg alloys containing LPSO phases were investigated in the regime of very high cycle fatigue to clarify the effect of LPSO phase on the crack initiation and small crack propagation process at both microscopic and atomic scales.
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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
1. Ultrasonic fatigue tests were carried out on the extruded Mg-Gd-Y alloys (GW103k), casted Mg-Gd-Y-Zn alloys and soluted Mg-Gd-Y-Zn alloys
2. Fatigue crack initiation and early propagation behaviors as well as the effect of microstructural heterogeneouty on the fatigue behavior were studied.
3. TEM observation of fatigue crack initiation sites at atomic scale was performed. A new segregation mode of rare earth elements caused by the motion of basal dislocations was found.
4. Partial results were presented at the 71th Annual Meeting of Japan Society of Mechanical Engineers and published a paper on journal of Materials Science and Technology.
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| 今後の研究の推進方策 |
By comparison of three kinds of Mg-Gd-Y-Zn-Zr alloys, the effects of LPSO phase on fatigue crack initiation and its early propagation will be clarified. The crack path and fatigue crack propagation rate will be investigated using a specially designed CT specimen. Fatigue fracture mechanism included that governs cyclic deformation in the VHCF regime will be illucidated using SEM, EBSD, FIB and HRTEM. Some critical ideas for microstructure design are expected to improve the super long life strength of Mg alloys.
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