| 研究課題/領域番号 |
22KF0310
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| 補助金の研究課題番号 |
22F22720 (2022)
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| 研究種目 |
特別研究員奨励費
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| 配分区分 | 基金 (2023)
補助金 (2022) |
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| 応募区分 | 外国 |
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| 審査区分 |
小区分18010:材料力学および機械材料関連
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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 |
CHEN YAO 九州大学, 工学研究院, 外国人特別研究員
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| 研究期間 (年度) |
2023-03-08 – 2025-03-31
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| 研究課題ステータス |
完了 (2024年度)
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| 配分額 *注記 |
2,200千円 (直接経費: 2,200千円)
2024年度: 600千円 (直接経費: 600千円)
2023年度: 1,100千円 (直接経費: 1,100千円)
2022年度: 500千円 (直接経費: 500千円)
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| キーワード | Mg-RE alloy / Very-high-cycle fatigue / Heat treatment / β' nano-precipitates / Damage accumulation / Nano-precipitates / Crack nucleation / Very high cycle fatigue / Crack initiation / Oxidation / Oxygen embrittlement |
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| 研究開始時の研究の概要 |
The proposed research is to undertake quasi-in situ fatigue observation to characterize fatigue transitions from a crack-free stage to a cracked stage, and further short crack growth stage. This study aims at revealing dislocation structures associated with nucleation of microcracks and connecting atomic scale deformation with macroscopic fatigue performance.
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| 研究実績の概要 |
For the beta prime nanoprecipitates and LPSO co-strengthened Mg-RE alloy, unique oxide nodules are observed as a type of fatigue damage that facilitates crack initiation, differing from typical slip-band structures. The presence of LPSO lamellae and dense distributed beta prime nano-precipitates contributes to the high localization of fatigue damage in the form of oxide nodules. These fatigue-induced oxide nodules form and expand within the soft alpha-Mg layer, but their growth is constrained by the surrounding strong LPSO lamellae, resulting in microcrack nucleation. Ultimately, clusters of microcracks along the LPSO/oxide interface merge along the damage bands, leading to the trans-granular crack initiation. Due to the synergistic effect of the LPSO lamellae and the dense beta prime nanoprecipitates, the fatigue life is accordingly prolonged compared to the LPSO-strengthened Mg-RE alloy. The findings offer valuable insights into the potential for designing and modifying microstructures to enhance the fatigue performance of Mg-RE alloys.
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