2021 Fiscal Year Final Research Report
Development of Ultra-Lightweight High-Strength Heat-Resistant Magnesium Alloys with Excellent Nonflammability by Utilizing Advanced High-Temperature Strengthening Mechanism
| Project/Area Number |
19K05054
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 26040:Structural materials and functional materials-related
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
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| Project Period (FY) |
2019-04-01 – 2022-03-31
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| Keywords | マグネシウム合金 / 高温強度 / ラメラ組織 / 高分解能電子顕微鏡 / 転位 |
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| Outline of Final Research Achievements |
An ultra-lightweight high-strength heat-resistant magnesium alloy with excellent nonflammability has been developed by utilizing the advanced high-temperature strengthening mechanism. We successfully produced the Mg-Ca two-phase alloy with a lamellar spacing of 900 nm, and investigated the academic knowledges necessary for its application as a high-temperature structural material. The temperature range where the fine lamellar structure in the developed alloy is thermally stable is below 573 K, and the lamellar microstructure coarsens above 573 K. When this alloy is creep-tested at 473 K, the lower minimum creep rate is obtained with decreasing the lamellar spacing, indicating that the lamellar interface plays a creep-strengthening role. It was elucidated that the creep for the alloy is controlled by the high-temperature climb of dislocations.
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| Free Research Field |
高温金属強度学，金属組織制御学，高温構造材料
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| Academic Significance and Societal Importance of the Research Achievements |
本研究の社会的意義として，エンジン周辺部の高温構造部材の軽量化を通じて，自動車の燃費向上を飛躍的に推進できることが挙げられる。また，学術的意義として，異相界面強化と称する新規な高温材料強化機構を世界で初めて提案し，実証したことが挙げられる。この新規な高温材料強化機構を最大限に発現できるよう，サブミクロンサイズの微細な層状組織に組織制御した点が独創的である。従来の高温構造材料とは全く新しい概念の金属組織を有する本開発合金について，基礎的な学術的知見として，組織安定性，界面構造，および，高温強度特性を明確化した。本研究において用いた研究手法は，今後，様々な合金系に適用できるものと期待される。
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