Fabrication of High-Porosity Lotus-Type Porous Aluminum in Vacuum

被引：0

作者：

Xiaobang Liu

Yanxiang Li

Yun He

机构：

[1] Tsinghua University,School of Materials Science and Engineering

[2] Tsinghua University,Key Laboratory for Advanced Materials Processing Technology (MOE)

来源：

Metallurgical and Materials Transactions A | 2017年 / 48卷

关键词：

Hydrostatic Pressure; Capillary Pressure; Hydrogen Pressure; Graphite Crucible; Liquid Aluminum;

D O I：

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学科分类号：

摘要：

Lotus-type porous aluminums with porosities from 10 to 26 pct were fabricated with the Bridgman-type directional solidification method (Gasar). A vacuum atmosphere is critical to obtain high-porosity lotus-type porous aluminum by the Gasar process. The lotus-type porous aluminum was directionally solidified under a pure hydrogen pressure of 0.2 to 16 kPa. The influence of hydrogen pressure on the porosity and pore size in vacuum was investigated. The porosity and pore size increase with decreasing hydrogen pressure, but there exists a maximum porosity at some critical hydrogen pressure. Since a low hydrogen pressure is adopted, the effect of capillary pressure and hydrostatic pressure on the porosity becomes important. With the decreasing of hydrogen pressure, the influence of hydrostatic pressure and capillary pressure on porosity becomes stronger and stronger. The influence of melt height, which is proportional hydrostatic pressure, on porosity and pore size was investigated. The calculated porosities considering capillary pressure and hydrostatic pressure are in good agreement with experimental results.

引用

页码：1264 / 1272

页数：8