The Anisotropy of Replicated Aluminum Foams

Eugeny L Furman,Maxim L Cherny,Arcady B Finkelstein

doi:10.1155/2014/230767

Eugeny L Furman, Maxim L Cherny + Show 1 more

Open Access

https://doi.org/10.1155/2014/230767

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Abstract

The replication casting process gives the open-cell aluminum foams that can be used in many industrial applications as well as in filtering technology. The essential requirement for filters is the uniformity of filtering degree which is defined by the minimal pore size. However the structure of replication castings is often inhomogeneous and the minimal pore radius is decreasing in the direction of melt infiltration. The objective of this investigation is to study the dynamics of melt impregnation of the porous medium by vacuum suction to identify the possibility of reducing the anisotropy. Theoretical data illustrate the processes at the boundary between melt and gas medium. The experiments were carried out using the replication aluminum samples produced according to commercial technology. It was found that the permeability coefficient varies throughout the height of castings. A method for estimation of pressure on the line of melt movement was proposed. The resistance of NaCl layer and circular vents of the mold causes the inhomogeneity of castings. Finally the ways of minimizing the anisotropy were offered.

Highlights

Aluminum open-cell foams can be applied in a wide range of possible applications [1]
The replicated aluminum foam obtained with vacuum suction has a porosity in the range of 50–65% which is higher than that for sintered porous structures and lower than that for replication casting under high pressure [2, 3]
The present paper shows that it is impossible to decrease a relative amount of inhomogeneous area theoretically

Summary

Introduction

Aluminum open-cell foams can be applied in a wide range of possible applications [1]. The replicated aluminum foam obtained with vacuum suction has a porosity in the range of 50–65% which is higher than that for sintered porous structures (around 30–35%) and lower than that for replication casting under high pressure (up to 90%) [2, 3]. The essential requirement for filters is the uniformity of filtering degree which is defined by the minimal pore size (2rmin) This task can be solved with technology [3], when prebaked sodium chloride (NaCl) layer is infiltrated with aluminum melt under high pressure. In this case the minimal pore size is determined by the time of NaCl baking. The objective of this investigation is to study the dynamics of melt impregnation of the porous medium by vacuum suction to identify the possibility of reducing the anisotropy

Theory

Experimental

Findings

Discussion

Conclusion