Metallurgical and Materials Transactions A

, Volume 43, Issue 13, pp 5140-5152

First online:

Fabrication of Porous Aluminum with Directional Pores through Continuous Casting Technique

  • T. IdeAffiliated withThe Institute of Scientific and Industrial Research, Osaka University
  • , Y. IioAffiliated withThe Institute of Scientific and Industrial Research, Osaka UniversityNew Nippon Steel Company, Ltd.
  • , H. NakajimaAffiliated withThe Institute of Scientific and Industrial Research, Osaka University Email author 


Lotus-type porous aluminum with slender directional pores is fabricated via a continuous casting technique in pressurized hydrogen or a mixed gas containing hydrogen and argon. The influence of solidification conditions such as hydrogen partial pressure, solidification velocity, temperature gradient, and melt temperature on the porosity and pore size is investigated. The porosity and pore size increase upon increasing the hydrogen partial pressure or the melt temperature, whereas the porosity and pore size decrease upon increasing the solidification velocity or the temperature gradient. Furthermore, the mechanism of pore formation in lotus aluminum is examined based on the results of an improved model of hydrogen mass balance in the solidification front, which was originally proposed by Yamamura et al. The results from the present model agree with the experimental results. We conclude that the diffusion of hydrogen rejected in the solidified aluminum near the solid/liquid interface is the most important factor for pore formation because the difference in hydrogen solubility between solid and liquid aluminum is very small.