The Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan.
Proc Jpn Acad Ser B Phys Biol Sci. 2010;86(9):884-99. doi: 10.2183/pjab.86.884.
Lotus-type porous metals with aligned long cylindrical pores are fabricated by unidirectional solidification from the melt with a dissolved gas such as hydrogen, nitrogen, or oxygen. The gas atoms can be dissolved into the melt via a pressurized gas atmosphere or thermal decomposition of gaseous compounds. Three types of solidification techniques have been developed: mold casting, continuous zone melting, and continuous casting techniques. The last method is superior from the viewpoint of mass production of lotus metals. The observed anisotropic behaviors of the mechanical properties, sound absorption, and thermal conductivity are inherent to the anisotropic porous structure. In particular, the remarkable anisotropy in the mechanical strength is attributed to the stress concentration around the pores aligned perpendicular to the loading direction. Heat sinks are a promising application of lotus metals due to the high cooling performance with a large heat transfer.
莲状多孔金属具有定向长圆柱形孔，是通过从熔体中单向凝固制造的，熔体中溶解有氢气、氮气或氧气等气体。气体原子可以通过加压气体气氛或气态化合物的热分解溶解到熔体中。已经开发出三种凝固技术：模铸、连续区熔和连续铸造技术。从莲状金属的大规模生产的角度来看，最后一种方法是优越的。机械性能、吸声和导热率的各向异性观察到的各向异性是各向异性多孔结构所固有的。特别是，机械强度的显著各向异性归因于垂直于加载方向排列的孔周围的应力集中。由于具有较大的传热性能，因此散热器是莲状金属的一种很有前途的应用。
