Fatigue Characterization of Ultrahigh Strength and Ductile Mg-Gd-Y-Zn-Zr Alloy with Hierarchical Anisotropic Nanostructure

多级各向异性纳米结构超高强韧性Mg-Gd-Y-Zn-Zr合金的疲劳表征

• 批准号: 22KF0310
• 负责人: 陳 強
• 金额: $ 1.41万
• 依托单位: Kyushu University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for JSPS Fellows
• 财政年份: 2023
• 资助国家: 日本
• 起止时间: 2023-03-08 至 2025-03-31
• 项目状态: 未结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-22KF0310/
• 关键词: Mg-RE alloy; Very high cycle fatigue; Crack initiation; Oxidation; Oxygen embrittlement

We investigated the very high cycle fatigue behavior of a Mg alloy with long-period stacking ordered (LPSO) phase. Fatigue fracture and damage observation revealed that microcracks nucleate from the thick alpha-Mg layers, away from the dense LPSO lamellae. Notably, microcrack nucleation was observed inside the localized oxides. This investigation highlights the critical role of highly localized oxide thickening, orders of magnitude thicker than native oxide, in the process of microcrack nucleation. The proposed model reaffirms the importance of the extrusion/intrusion process, but more importantly highlights a mechanism in which fatigue-induced oxidation results in the embrittlement of the extrusion/intrusion structure, which in turn affects the nucleation of microcracks.

我们研究了具有长周期堆叠有序 (LPSO) 相的镁合金的极高循环疲劳行为。疲劳断裂和损伤观察表明，微裂纹从厚的 α-Mg 层中形核，远离致密的 LPSO 片层。值得注意的是，在局部氧化物内部观察到微裂纹成核。这项研究强调了高度局部氧化物增厚（比原生氧化物厚几个数量级）在微裂纹成核过程中的关键作用。所提出的模型重申了挤压/侵入过程的重要性，但更重要的是强调了疲劳诱导的氧化导致挤压/侵入结构脆化的机制，进而影响微裂纹的成核。