| Budget Amount *help |
¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000)
Fiscal Year 2012: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2011: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000)
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| Research Abstract |
Porous metals with directional pores aligned in one direction, called as lotus or gasar metals, exhibit superior mechanical and thermal properties compared with other porous metals with spherical pore. Therefore, lotus metals are expected to be used as heat sinks, impact energy absorber, etc. Thus, extensive studies have been carried out to develop new fabrication techniques and improve their properties. Recently, we developed a safer and cheaper fabrication technique for the lotus metals. Lotus metals are fabricated by utilizing a hydrogen solubility gap during solidification. So far, a fabrication technique using high pressure hydrogen has been investigated. However, there were two experimental difficulties. One is the need for a high pressure chamber which is expensive. Another is the use of hydrogen gas, which is flammable and explosive. In order to overcome these problems, a novel technique which uses gas-forming compounds as a gas source is developed. This method is called as the thermal decomposition method (TDM); gas atoms can dissolve in the melt through the thermal decomposition of the compound containing a gas element. In the present study, lotus copper is fabricated through the thermal decomposition method combined with a continuous casting techni que.The copper was melted in a graphite crucible by induction heating. The copper melt dropped downward into a tundish, in which pellets of titanium hydride were supplied at a constant time interval in order to maintain the dissolving hydrogen constant. Then to solidify the melt continuously, a graphite dummy bar pulled molten copper through a cooling mold at a constant transfer velocity.Porous copper with directional pore aligned in one direction was fabricated with the solidification velocity 80mm/minute and with addition of a pellet in argon atmosphere of 0.1MPa. Lotus -type porous copper can be fabricated through thermal decomposition method by continuous casting technique.
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