Nanoindentation of closed cell Al alloy foams subjected to different heat treatment regimes

Aluminium foams are lightweight porous materials with wide range of possible applications. In order to use them as a widespread construction material still many of their properties need to be fully investigated. Nanoindentation of closed cell aluminium foams was conducted in order to investigate cell wall mechanical properties. During this study AlMgSi0.6 foams with different cooling regimes after foaming and different subsequent heat treatments were tested in order to obtain insight into influence of mentioned parameters on cell wall properties such micro-hardness. Nanoindentation is a technique similar to the conventional hardness testing but preformed on a nano-scale level which makes it adequate technique for investigating thin films and layers but also thin walls of cellular materials such as metal foams. Aluminium alloy foam rod shaped samples were produced by means of powder compacts foaming method but with different subsequent heat treatment; some were air cooled and some were cooled in water. After cooling from foaming temperature some of the samples were subsequently heat treated while others were not which resulted in four types of samples. The highest values of hardness were detected for fully heat treated samples.