2004 Fiscal Year Final Research Report Summary
Development of Cavitation erosion resistant material using shape memory alloys
| Project/Area Number |
15560067
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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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 | University of Fukui |
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Principal Investigator |
HATTORI Shuji University of Fukui, Professor, 工学部, 教授 (00143933)
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| Co-Investigator(Kenkyū-buntansha) |
ITO Takamoto University of Fukui, Associate Professor, 工学部, 助教授 (40242581)
MAEKAWA Norihide University of Fukui, Research Associate, 工学部, 助手 (20262610)
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| Project Period (FY) |
2003 – 2004
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| Keywords | Cavitation erosion / Ti-Ni shape memory alloys / Hardness / Defect density |
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| Research Abstract |
Cavitation erosion occurs on the surface of the components that contact the fluid in many industrial machines such as the fluid machineries, hydraulic turbines and pumps. We have reported that the Ti Ni shape memory alloy is one of the erosion resistant materials, which shows an excellent erosion resistance.
In this study, the cavitation erosion tests of Ti-Ni base shape memory alloy was carried out with the addition of the third element to the regular Ti-Ni shape memory alloy to change mechanical properties and the transformation temperature. The erosion resistance with various third components was discussed through the observation by a scanning electron microscopy. It was founded that every test materials indicate a long incubation period of 5 to 20 times that as compared with austenitic stainless steel SUS304 used for the pipe of the nuclear power plants and so on. In general, erosion resistance of carbon steels has a good correlation with hardness. However, the Ti-Ni base shape memo
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ry alloys did not show a good correlation with hardness.
It was thought that the defect on the surface of the material influenced the erosion resistance. The density of initial defects was measured, and the erosion resistance is decreased with the increased density of the initial defects on the material surface. However, the correlation is not good enough for only taking account of the density of the initial defect. It was thought that not only the density of defects but also the spreading rate may influence the erosion. We measured the rate of the eroded area with a scanning electron microscopy. We summarized the erosion resistance as a function of the product of the spreading rate of the eroded area and the initial defect density such as pores. On the other hand, there is some relation between hardness and the spreading rate of the eroded area. Therefore, it is obtained that there is a good correlation between the erosion resistance and the product of the initial defect density and material hardness, which can be measured easily.
Therefore, it was concluded that the erosion resistance of Ti-Ni base shape memory alloy was influenced by both initial defect density and material hardness. Less
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