| Project/Area Number |
10450274
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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 |
Material processing/treatments
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| Research Institution | Hiroshima University |
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Principal Investigator |
YANAGISA Osamu Faculty of Engineering, Hiroshima University, Professor, 工学部, 教授 (50034393)
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| Co-Investigator(Kenkyū-buntansha) |
MATUGI Kazuhiro Faculty of Engineering, Hiroshima University, Professor, 工学部, 助手 (30253115)
HATAYAMA Haruaki Faculty of Engineering, Hiroshima University, Professor, 工学部, 助教授 (50112181)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥4,800,000 (Direct Cost: ¥4,800,000)
Fiscal Year 1999: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1998: ¥4,300,000 (Direct Cost: ¥4,300,000)
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| Keywords | powder rolling, spark sintering / rapidly solidified powder / aluminum alloys / 放電焼結圧延 |
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| Research Abstract |
The sintering of aluminum materials is difficult, since their affinity for oxygen is very high and their temperature range for sintering is very narrow. The advantage of spark sintering is summarized as follows : (1)The dielectric breakdown of the oxide film is caused between the powder particle surfaces, (2)The sintering process is finished under the condition of the shorter low temperature exposure. In order to develop the high strength aluminum sheet, the technique, (hereafter called powder rolling-spark sintering process), having both process of powder rolling and spark sintering for fabrication of metallic sheet is used for cold rolling and spark sintering of 7075-rapidly solidified aluminum powder in this study. The obtained results are summarized as follows :
1. Only surface temperature of materials can be measured by radiation pyrometer (non-contact infrared thermometer with laser beam targeting) in the powder rolling-spark sintering process. However, the inner temperatures of m
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aterials is important in the sintering process. The real temperatures of graphite punches and compacts are measured by using of thermo couples in the die-press style spark sintering machine. The relation between temperature of materials-surface and one materials-center is obtained from these measurements.
2. The various microstructures is obtained by changing of process parameters, such as holding temperature, period of sintering and cooling method. The microstructural changes is investigated using TEM and x-ray diffraction techniques. The solid soluted amount of main alloying elements increases as the holding temperature and period increase, which results in substitution of both homoginizing and solution heat treatments.
3. The behavior of age-hardening is same for materials sintered at 873K for 10 to 2400 sec. On the other hand, plastic strain of material increases as the holding period in the sintering at 873K increases, and that of materials sintered at 873K for 1200sec is same as that of solution treated materials. It is suggested on the basis of value of the plastic strain obtained from tensile test that materials sintered under the conditions of the long exposure and higher temperatures show largely solid-soluted amount of main alloying elements and promotion of sintering.
4. The computer soft for solidification analysis is modifed for spark sintering process. The thermal analysis including current-, voltage-change and heat generation process is carried out. Less
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