2006 Fiscal Year Final Research Report Summary
Nano-Crystallization by Using Cavitation Shotless Peening
| Project/Area Number |
17360047
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Materials/Mechanics of materials
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| Research Institution | Tohoku University |
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Principal Investigator |
SOYAMA Hitoshi Tohoku University, Graduate School of Engineering, Professor, 大学院工学研究科, 教授 (90211995)
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| Co-Investigator(Kenkyū-buntansha) |
WATANABE Yutaka Tohoku University, Graduate School of Engineering, Associate Professor, 大学院工学研究科, 助教授 (10260415)
YAMANAKA Masashi Tohoku University, Graduate School of Engineering, Associate Professor, 大学院工学研究科, 助教授 (20292229)
KAI Akira Tohoku University, Graduate School of Engineering, Research Associate, 大学院工学研究科, 助手 (20422082)
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| Project Period (FY) |
2005 – 2006
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| Keywords | Peening / Cavitation / Grain size / Fatigue strength / Surface modification / Residual stress / Hardness / Micro strain |
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| Research Abstract |
The main results obtained are as follows:
1. Cavitation impact was increased by increases of injection pressure of cavitating jet and an ambient pressure at cavitation bubble collapsing region. Novel cavitation shotless peening, which use a cavitating jet in water with associated water jet, was proposed and it was revealed that the ability of the jet was increased.
2. In order to make clear a mechanism of improvement of fatigue strength by cavitation shotless peening, residual stress was precisely measured by using an X-ray diffraction method. It was revealed that residual stress was closely related to the improvement of fatigue strength by cavitation shotless peening.
3. A fundamental parameter approach was tried to evaluate grain size and micro strain. It was revealed that the fundamental parameter approach can evaluate them. It was found that cavitation shotless peening relieved micro strain with introducing macro strain, i.e., compressive residual stress.
4. It was revealed that plastic deformation depth, elastic deformation depth and maximum deformation depth could evaluate the characteristics of the surface treated by cavitation shotless peening using indentation test.
5. In order to make clear the mechanism of gettering using cavitation shotless peening, the gettering site of silicon wafer was observed by using a transmitting electron microscope, the gettering site was consist of the dislocations whose size was about 100 nm.
6. Cavitation impact was increased by changing nozzle outlet geometry, the peening effect was increased, and then the improvement of fatigue strength was also increased. It was revealed at treatment of gear teeth that the consideration of flow pattern at mechanical parts of cavitation shotless peening was very important.
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Research Products
(47 results)
