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Wednesday, June 25, 2008 - 10:30 AM

Commercially Viable Nanostructured Aluminum for Coatings and Structural Applications

G. E. Kim, Perpetual Technologies, Inc., Ile des Soeurs, QC, Canada; A. L. Moran, United States Naval Academy, Annapolis, MD; B. Jodoin, University of Ottawa, Ottawa, ON, Canada; T. Addona, n-WERKZ, Ile des Soeurs, QC, Canada

A new means of producing nanostructured aluminum alloy (i.e., AA5083) powder at a lower cost has been developed by n-WERKZ Inc. The new powder processing method does not use high cost liquid nitrogen, which was relied upon by prior methods to attain nanostructured metal powder. Cold sprayed deposits of the powder showed the ability to deposit dense, well-adhered nanostructured AA5083 coatings without any signs of grain growth. With the knowledge that bulk materials of the same composition show lower propensity for localized corrosion with finer grain size, a corrosion study will be carried out to determine if the same holds true in coating form. If so, this may be a viable means of repairing localized damage in protective coatings and/or structures, as well as its application for superior corrosion/wear protection. Sample powder of the nanostructured AA5083 powder was used to produce bulk parts that were machined and tested under tension. The preliminary tensile test results revealed average yield and ultimate strengths of 400 and 490 MPa, respectively. The most surprising result was the average elongation of 15%, not typically seen on materials processed in similar manner, especially without liquid nitrogen which, amongst other things, helps mitigate oxidation during processing. Knowing that the issue of elongation has been addressed for the nanostructured AA5083, focus will shift towards exploring the further enhancement of its strength.

Summary: A novel means of processing nanostructured aluminum alloy powder in a commercially viable manner has been developed. The new approach does not incorporate the use of costly liquid nitrogen yet can accomplish grain refinement at shorter processing times. Nanostructured aluminum alloy powder shows great promise in providing superior corrosion/wear protection in coating form; and, in enabling the production of superior strength aluminum-base structures.