Development of Aluminium Foam Processes and Products
Aluminum foams offer an attractive combination of attributes as engineering materials, such as low density, high rigidity, high energy absorption, and fire resistance. To date, however, metallic foams have achieved only a fraction of the market acceptance enjoyed by polymeric foams, owing largely to size limitations, poor uniformity and, above all, high unit costs. Methods utilizing casting (non-powder) metallurgy, while seemingly offering the potential of economies of scale, often suffer quality issues such as large cell sizes, poor uniformity and insufficient structural integrity. Many of these problems are associated with the rheology of the molten metal itself. While prior efforts to modify melt rheology through extrinsic additions of ceramic particles have been shown to be effective, the costly materials and processing paths used to create such suspensions have limited the economic attractiveness of such products. In this paper, aluminum foams produced through an alternative processing method will be described. The physical and mechanical properties in these fine (< 1 mm) celled aluminum foams will be related to their cellular structure and the properties of the aluminum alloy matrix from which they are produced.
W.J. Poole, M.A. Wells and D.J. Lloyd
J. D. Bryant, D. Wilhelmy, J. Kallivayalil, W. Wang, "Development of Aluminium Foam Processes and Products", Materials Science Forum, Vols. 519-521, pp. 1193-1200, 2006