9:45 AM BB6.5
LOW
PRESSURE SPRAY FORMING OF 2024 ALUMINUM ALLOY. W.D. Cai,
J. Smugeresky* and E. J. Lavernia Department of Chemical,
Biochemical Engineering and Materials Science, University of
California, Irvine, CA, *Sandia National Laboratories, Livermore, CA.
In this paper, a newly developed low pressure spray
forming (LPSF) technique is described. The experimental results
obtained with an as-deposited 2024 aluminum alloy are reported. It
is shown that the application of reduced pressure significantly
decreases porosity as compared to conventionally spray formed 2024
aluminum alloy. Moreover, the resultant microstructures are similar
to those achieved with conventional spray forming. The mechanisms of
porosity formation in deposited materials, obtained using both low
pressure and conventional spray forming, are discussed. Gas
entrapment and interstitial porosity are proposed to be the two major
sources of the porosity present in the as-deposited materials. On
the basis of the present study, the controlled low pressure
environment during LPSF, appears to influence the droplet
trajectories and the gas flow field, leading to flow straightening
effects which result in significant reduction of porosity in the
deposited materials.
Work supported by the Army Research Office (Grant No.
DAAH04-95-1-0424), and U.S. Department of Energy (Contract No.
DE-AC04-94AL85000)
SESSION BB7: MECHANICAL PROPERTIES - A
Chairs: Daniel
Sordelet and Subra Suresh
Thursday Morning, December 4, 1997
Essex North/Center (W)
