New principle for low-temperature-high-strain-rate superplasticity in Titanium alloy by means of novel microstructural control technique
| Project/Area Number |
25709068
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| Research Category |
Grant-in-Aid for Young Scientists (A)
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| Allocation Type | Partial Multi-year Fund |
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| Research Field |
Material processing/Microstructural control engineering
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| Research Institution | Kagawa University |
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Principal Investigator |
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| Project Period (FY) |
2013-04-01 – 2016-03-31
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| Project Status |
Completed (Fiscal Year 2015)
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| Budget Amount *help |
¥25,610,000 (Direct Cost: ¥19,700,000、Indirect Cost: ¥5,910,000)
Fiscal Year 2015: ¥3,250,000 (Direct Cost: ¥2,500,000、Indirect Cost: ¥750,000)
Fiscal Year 2014: ¥8,060,000 (Direct Cost: ¥6,200,000、Indirect Cost: ¥1,860,000)
Fiscal Year 2013: ¥14,300,000 (Direct Cost: ¥11,000,000、Indirect Cost: ¥3,300,000)
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| Keywords | 航空機チタン合金 / 超塑性 / マルテンサイト / 超微細粒組織 / 変形機構 / チタン合金 / 超塑性変形 / 微細粒組織 / マルテンサイト変態 / 動的再結晶 / 準安定状態 / 有限要素解析 / 機械材料・材料力学 / 超塑性成形 / 組織制御 |
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| Outline of Final Research Achievements |
This work revealed that ultrafine-grained Ti-6Al-4V alloy (α’-UFG) produced by new type of processing exhibited low-temperature-high-strain-rate superplasticity at the highest level. Herein, dynamic β precipitation from a metastable single α starting microstructure (occurred under deformation) contributed to a stress-accommodation mechanism. Accompanied by this dynamic β-precipitation, grain boundary sliding mode of theα’-UFG dynamically evolved from the type of the Ball-Hutchison model to the type of the Gifkins Core-Mantle model. In addition, high ductility at high temperature is also obtained in the martensite starting microstructure. This is due to the frequent occurrence of dynamic recrystallization during deformation, resulting in enhancement of stress-accommodation and grain-boundary-sliding. Similar behavior has been also confirmed in Ti-6242 alloy. So, formation of metastable starting microstructure was found to be new concept for enhancing the superplastic property.
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Report
(4 results)
Research Products
(17 results)
