Fabrication of lotus-type porous iron and its mechanical properties
Fabrication of lotus-type porous iron and its mechanical properties
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DOI：
10.1016/j.stam.2003.11.005
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发表时间：
2004-01-01
影响因子：
5.5
通讯作者：
Nakajima, H
中科院分区：
文献类型：
--
作者：
Hyun, SK;Ikeda, T;Nakajima, H
在氢气（氮气）和氩气的混合气体中，通过熔体的定向凝固制备了长圆柱形孔沿一个方向排列的多孔铁。由于液态和固态之间溶解度的差异，饱和在铁水中的氢和氮在凝固过程中被排斥在固-液界面处。气孔是由不溶于固体铁中的氢（氮）形成的，单向生长。在熔化和凝固过程中，孔隙率由氢（氮）和氩的分压控制。通过增加氩气分压，抑制了孔隙的形成，因为生长孔隙中的氢气（氮气）的压力和密度随气氛的总压力而增加。在氮气气氛下制备的固体铁中的氮浓度随氮气分压线性增加，导致多孔铁的机械性能的改善。孔取向与拉伸方向平行和垂直的多孔铁的极限抗拉强度和屈服强度约为氢气气氛下的两倍。这种上级强度是由于铁基体中溶质氮原子的固溶硬化所致。(C)2003爱思唯尔有限公司。保留所有权利。
Porous iron whose long cylindrical pores are aligned in one direction has been fabricated by unidirectional solidification of the melt in a mixture gas of hydrogen (nitrogen) and argon. Both hydrogen and nitrogen saturated in the molten iron are rejected at the solid-liquid interface during the solidification due to the difference Of Solubility between the liquid and the solid. The gas pores are evolved from the hydrogen (nitrogen) insoluble in the solid iron,which grow unidirectionally. The porosity is controlled by the partial pressures of hydrogen (nitrogen) and argon during melting and solidification. By increasing the partial pressure of argon gas the pore formation is suppressed, since the pressure and, therefore, the density of the hydrogn (nitrogen) gas in the growing pore are increased with the total pressure of the atmosphere.The nitrogen concentration in solid iron fabricated under nitrogen atmosphere increases linearly with partial pressure of nitrogen, leading to the improvement of mechanical properties of the porous iron. The ultimate tensile strength and the yield strength of the porous iron with the pore orientation parallel and perpendicular to the tensile direction are about twice as high as those under hydrogen atmosphere. Such superior strength is attributed to the solid-solution hardening due to solute nitrogen atoms in iron matrix. (C) 2003 Elsevier Ltd. All rights reserved.