Strain rate and density-dependent strength of AlSi7 alloy foams

Foams are able to absorb energy and bear stress more uniformly and efficiently than the correspondent bulk materials. This makes them ideal candidates to increase the specific structure's absorption efficiency. Concerning their characterisation, there are still some open issues needing further investigations, such as the experimental analysis of their dynamic behaviour with alloy types, strain rates and foam density changes. This paper focuses on the above mentioned issues presenting the results of a dynamic characterisation by means of a direct tension-compression Hopkinson bar. Tests are carried out on AlSi7 alloy foam specimens obtained from a large ingot made by compact powder technology. The results are discussed mainly in terms of strength and energy absorption efficiency, considering the effects of strain rate and of the variation of foam density, due to the manufacturing process. (C) 2015 Elsevier B.V. All rights reserved.