2019 Fiscal Year Final Research Report
Development of a strong and ductile Ti-based bulk multi-gradients material utilizing friction stir powder surface processing technique and phase transformation theory
Project/Area Number |
18K14027
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Research Category |
Grant-in-Aid for Early-Career Scientists
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Allocation Type | Multi-year Fund |
Review Section |
Basic Section 26050:Material processing and microstructure control-related
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Research Institution | Osaka University |
Principal Investigator |
LIU HUIHONG 大阪大学, 接合科学研究所, 助教 (40748943)
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Project Period (FY) |
2018-04-01 – 2020-03-31
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Keywords | 摩擦攪拌プロセス / Ti合金 / 微細構造制御 / 力学的特性 |
Outline of Final Research Achievements |
A beta Ti-alloy (Ti-15V-3Cr-3Sn-3Al) sheet was lap-joined to an alpha pure-Ti sheet by friction stir processing in order to ultra-refine and beta-alloying the alpha-Ti surface. The same processing was also performed on the opposite side of the pure-Ti sheet. The fabricated specimen was then solution treated and aged to introduce phase transformation in the beta-Ti-alloy surfaces. The microstructure analysis indicates that different microstructures consisting of different chemical compositions, grain sizes, grain boundary characteristics, grain orientation characteristics, and phase constitutions, were generated and distributed from the specimen surface to the core. The tensile property results suggest that the fabricated specimens with or without heat treatment show high strength close to those of the high-strength beta Ti alloy with or without aging, and large elongation close to or larger than that of the alpha pure Ti, respectively.
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Free Research Field |
金属材料、材料加工、組織制御、固相接合、異種接合
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Academic Significance and Societal Importance of the Research Achievements |
本研究成果は、工業用途に向け強度延性が両立する新規Ti基バルク構造材料を開発しただけでなく、摩擦攪拌プロセスを利用して他の特異構造を有する高性能材料の開発に対して研究指針の一つになる。本概念に基づいて、化学組成、結晶粒径、結晶粒界特徴、結晶方位特徴、および相構成などを制御・工夫することで、特異微細構造を設計することができ、特定用途に向け特定性能を有する構造材料を設計することが期待される。
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