2023 Fiscal Year Final Research Report
Mechanism and control principle of dislocation generation in late-stage of martensitic transformation
| Project/Area Number |
21K14426
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 26040:Structural materials and functional materials-related
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| Research Institution | Kobe University |
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Principal Investigator |
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| Project Period (FY) |
2021-04-01 – 2024-03-31
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| Keywords | 形状記憶合金 / マルテンサイト変態 / 弾性率 / マイクロメカニクス |
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| Outline of Final Research Achievements |
In order to improve the lifetime of shape memory alloys, the locations of dislocations and their internal stress fields were investigated experimentally and numerically based on micromechanics. Initially, dislocations were predicted to form at the interface between martensitic crystals that form the internal structure, however, they were mainly observed around or inside the martensitic crystals. The observed dislocations corresponded to dislocations that effectively relax internal stresses based on the internal stress field analysis. It was also shown that the elastic anisotropy in the elastic constants of the parent and martensitic phases could be made closer to each other to reduce the stress generated by the dislocations.
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| Free Research Field |
構造機能材料
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| Academic Significance and Societal Importance of the Research Achievements |
マイクロメカニクスによる内部応力解析と内部構造観察結果を組み合わせることにより，マルテンサイト晶に発生する結晶格子の歪み，弾性率と内部応力場，転位の関係を明確にした．特に材料の弾性率については内部応力場に影響を与える主要な物性であるにも関わらずこれまで明確な設計指針が示されてこなかったが，本研究により弾性異方性に着目した物性制御が転位抑制に効果的であることが示唆され，形状記憶合金の材料設計における未開拓領域を開拓した．
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