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GASAR Porous Metals Process Control

Published online by Cambridge University Press:  10 February 2011

J. M. Apprill ,
D. R. Poirier ,
M. C. Maguire  and
T. C. Gutsch
J. M. Apprill
Affiliation:
M.S.E. Department, University of Arizona, Tucson, AZ 85721, apprill@u.arizona.edu
D. R. Poirier
Affiliation:
M.S.E. Department, University of Arizona, Tucson, AZ 85721, apprill@u.arizona.edu
M. C. Maguire
Affiliation:
Sandia National Laboratories, P.O. Box 5800, M/S #1134, Albuquerque, NM 87185
T. C. Gutsch
Affiliation:
California State University, Chico, CA
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Abstract

GASAR porous metals are produced by melting under a partial pressure of hydrogen and then casting into a mold that ensures directional solidification. Hydrogen is driven out of solution and usually grows as quasi-cylindrical pores normal to the solidification front. Experiments with pure nickel have been carried out under processing conditions of varying H2 partial pressure, total pressure (H2 + Ar), and superheat. An analysis that considers heterogeneous bubble nucleation was developed that identifies processing conditions in which hydrogen bubbles are stable in the liquid before solidification. It is hypothesized that these conditions lead to low porosity because these bubbles float out of the melt and “escape” the advancing solidification front. Experimental data are shown to support this hypothesis.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 521: Symposium R – Porous & Cellular Materials for Structural Applications , 1998 , 291
Copyright
Copyright © Materials Research Society 1998

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References

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