2022 Fiscal Year Annual Research Report
Characterization of Crack Nucleation in Titanium Alloys with Metastable Microstructures
| Project/Area Number |
20F40737
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| Research Institution | Kyushu University |
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Principal Investigator |
陳 強 九州大学, 工学研究院, 教授 (30264451)
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| Co-Investigator(Kenkyū-buntansha) |
LIU HANQING 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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| Project Period (FY) |
2020-11-13 – 2023-03-31
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| Keywords | Titanium alloy / Metastable / Electron Beam Welding / Fatigue / Crack nucleation / Slip deformation / Twinning / Recrystallization |
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| Outline of Annual Research Achievements |
Definitive evidence for the nanostructured process within FGA is provided by a multi-scale characterization of the nanograin orientation, grain rotation, and the lattice strain up to atom scale by utilizing the transmission Kikuchi diffraction (TKD) and aberration-corrected scanning transmission electron microscope. Direct aging treatment can be used to optimize the mechanical properties of the weldment by decomposition of the thermal martensites and precipitation of the nano lamellar alpha structure within the coarse beta grain, thereby enhancing the crack nucleation resistance. Cracking interfaces of the oxidation domain and topmost nanograins facilitate surface degradation, thereby promoting the stress mismatch along the contact area boundary and giving rise to the formation of macrocrack thereafter with the assistance of oxygen pick-up at the crack tip.
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| Research Progress Status |
令和4年度が最終年度であるため、記入しない。
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| Strategy for Future Research Activity |
令和4年度が最終年度であるため、記入しない。
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