| Project/Area Number |
62460190
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
金属加工(含鋳造)
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| Research Institution | Osaka University |
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Principal Investigator |
OHNAKA Itsuo Osaka University, Faculty of Enginering, Professor, 工学部, 教授 (00029092)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAUCHI Isamu Osaka University, Faculty of Engineering, Lecturer, 工学部, 講師 (60029189)
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| Project Period (FY) |
1987 – 1988
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥6,800,000 (Direct Cost: ¥6,800,000)
Fiscal Year 1988: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1987: ¥5,800,000 (Direct Cost: ¥5,800,000)
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| Keywords | rapid solidification / solidified structure / alloy particle / laser beam / amorphous alloy / A1-alloy / 自由落下 / レーザー加熱 / 過冷却 / 微小合金粒子 / 光ビーム溶融法 |
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| Research Abstract |
The purpose of this two-year research is to develop a method whichcan measure more accurate relationship between rapidly solidified structure and cooling rate, and to conside the fornation mechanism of rapidly solidified structure based on the relation.
First,a drop tube technique has been tried,where an alloy particle of 50-100 m in diameter is melted by laser irradiation during falling and subsequently cooled rapidly by forced convection heat transfer. However,it was difficult to melt the particle by 5KW YAG laser because the heat transfer from the particle to gas atmosphere at the room temperature is too large. Therefore, convection heating by electric heater was used. Further,another technique was developed where a particle at rest is melted by the laser and the cooling curve is measured by a photosensor. This laser technique was applied for melting and solidification of a particle covered by glass to prevent surface heterogeneous nucleation. However,it was difficult to cool it rapidly, because a gap has developed between the particle and the glass.
Some data on the relation between cooling rate(10^4-10^5K/S) and solidified structure have been obtaied by the techniques for Al-alloys and amorphous-alloy particles. The consideration of the formation mechanism of repidly solidified structure based on the data revealed that not only the crystal nucleation but also the rate of the crystal growth has large effect on undercooling ,hence on the solidified structure.
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