Improvement of aluminium foam technology by tailoring of blowing agent

Aluminium foams produced by melting powder compacts containing a blowing agent are usually non-uniform which might lead to inferior mechanical properties. The reasons for this can be thermal gradients during foaming and a blowing agent which is not adapted to the melting range of the alloy to be foamed. We discuss various strategies to improve aluminium foams and then demonstrate that titanium hydride (TiH2) can be tailored by selective oxidation and partial discharge to yield more uniform foams. We find that the expansion potential of the foams and the uniformity of cell size distribution is improved and that the individual cell walls are smoother and less corrugated when the foam is blown with pre-treated TiH2. (c) 2005 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.