Analytical solutions for dynamic deformation of foam materials during the Taylor cylinder-Hopkinson bar impact experiment were obtained. It was shown that shock wave of foam collapse appears during the fast impact. The results of this experiment can be used in estimating the average material properties of the foam under dynamic loading conditions. Results show that the undeformed and change in length of foam specimens are in good agreement between theory and experiment, as well as numerical analysis.

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The foaming behavior of SiC-particulate (8.6% by volume) aluminum composite powder compacts contained Titanium Hydride blowing agent was investigated by heating above the melting temperature (750• C) in a pre-heated furnace. Aluminum powder compacts were also prepared and foamed using similar compaction and foaming parameters in order to determine the effect of SiC-particulate addition on foaming and compression behavior. The linear expansions of the compacts at various furnace holding times were ex situ determined. Optical and scanning electron microscopy techniques were used to characterize prepared and deformed foams microstructures. The SiC-particulate addition was found to increase the linear expansion and reduce the extent of the liquid metal drainage and cell coarsening of the aluminum compacts. The composite foam samples also showed higher compressive stresses, but a more brittle behavior as compared with aluminum foams. C 2003 Kluwer Academic Publishers IntroductionAluminum (Al) closed-cell foams are materials of increasing importance because they have good energy absorption capabilities combined with good thermal and acoustic properties. They can convert much of the impact energy into plastic energy and absorb more energy than bulk metals at relatively low stresses [1]. When used as filling materials in tubes, they increase total energy absorption over the sum of the energy absorbed by foam alone and tube alone [2,3].Al closed-cell foams are currently manufactured by several different processes. In a process patented by Alcan International Limited, the liquid metal is foamed by injecting gases (e.g., air or nitrogen) into the melt [4]. In the Alporas process, developed in Japan, a blowing agent (TiH 2 ) is added into the melt and the melt is then stirred quickly in order to form a homogeneous distribution of blowing agent [5]. The decomposition of the blowing agent, which releases hydrogen gas into the melt, drives the expansion of the melt. Foaming of powder compact process, patented by, e.g., Fraunhofer CMAM, starts with mixing and compaction of metal powders with a blowing agent in order to form a foamable precursor material [6]. Heating of the precursor to or above the melting temperature results in decomposition of blowing agent and simultaneously expansion

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