| Project/Area Number |
15K05677
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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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| Research Field |
Materials/Mechanics of materials
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| Research Institution | Kobe University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
中井 善一 神戸大学, 工学研究科, 教授 (90155656)
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| Co-Investigator(Renkei-kenkyūsha) |
AMEYAMA Kei 立命館大学, 理工学部, 教授 (10184243)
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| Project Period (FY) |
2015-04-01 – 2018-03-31
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| Project Status |
Completed (Fiscal Year 2017)
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| Budget Amount *help |
¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000)
Fiscal Year 2017: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2016: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2015: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
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| Keywords | チタン / 粉末冶金 / 疲労 / 金属疲労 |
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| Outline of Final Research Achievements |
Titanium alloy (Ti-6Al-4V) with a bimodal harmonic structure, which consists of a coarse-grained structure surrounded by a network structure of fine equiaxed grains, was fabricated to achieve high strength and ductility. K-decreasing tests were conducted to investigate the near-threshold fatigue crack propagation. The crack growth rates in the harmonic structured material were higher than a material with coarse grains while the fatigue thresholds were lower. In some areas, fatigue cracks preferentially propagated across the network structure of fine grains. Furthermore, small fatigue crack propagation was examined under four-point bending. Fatigue crack paths were not influenced by the bimodal harmonic structure, and the crack growth rates in the harmonic structured Ti-6Al-4V were almost the same as those in a material with coarse grains. In contrast, the harmonic structured Ti-6Al-4V had a higher resistance of fatigue crack initiation, which resulted in an increase of fatigue limit.
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