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Porous Al Alloys by Local Melting and Diffusion of Metal Powders

Published online by Cambridge University Press:  10 February 2011

N. Wang
Affiliation:
Department of Materials Science, and Engineering University of Virginia, Charlottesville, VA 22903
E. A. Starke Jr.
Affiliation:
Department of Materials Science, and Engineering University of Virginia, Charlottesville, VA 22903
H. N.G. Wadley
Affiliation:
Department of Materials Science, and Engineering University of Virginia, Charlottesville, VA 22903
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Abstract

A novel method exploiting local melt and diffusion induced porosity is described for producing porous Al alloys. Aluminum powder and zinc powder were blended and cold-compacted to a near net shape. A porous AI-Zn alloy component was then formed by annealing the material above the melting point of zinc but below the solidus temperature of the alloy. Pores were generated by the diffusion of molten Zn into the solid Al grains. The pore structure is shown to be determined by the volume fraction, distribution, and size of the Zn powders in the powder mixture, and by time and temperature of the annealing heat treatment. The pores can be further expanded by incorporating small amounts of titanium hydride into the powder blend and conducting the annealing treatment above the decomposition temperature of the titanium hydride (T>447°C). Porosity levels of 45 vol.% have been achieved to date. This processing approach appears amenable to the production of sandwich panels with a gradient porosity core and fully dense face sheets, and is applicable to other solid solution systems.

Type
Research Article
Copyright
Copyright © Materials Research Society 1998

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References

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