Bending Stiffness of Aluminium Foams

The basic manufacturing processes of cellular materials have been briefly noted as well as the metal foam properties. The most widely used are the aluminium foams due to the following properties: very good insulation (thermal insulation and sound absorption), low density (mass), high specific rigidity in sandwich structures, very good impact damping, corrosion resistance, non-flammability, very good recyclability, etc. Almost the all properties are basically determined by the type of cells (closed or open), their size and distribution i.e. relative density. This article focuses on the testing and determining the bending stiffness for different foamed cross section shapes, which are very important for analysis of behaviour of the lightweight stiff construction elements. The round, quadratic, hexagonal and I-shapes have been made by powder metallurgical Foaminal-Alulight process. These shapes have been foamed from alloy AlSi10 precursor with foaming agent TiH2 having density of 1000 kg/m3 and all of the profiles have had the same cross section area and volume. The fourpoint bending test was applied. From the load-deflection diagram the bending stiffness (EI) has been calculated for each cross section shape. I-shaped profile has the highest bending stiffness comparing to the other shapes, which is in good correlation with bending stiffness of such solid shapes. The common relation between bending stiffness of foamed and solid shape, which include relative density, has been proposed.