Evaluation of compressive mechanical properties of Al-foams using electrical conductivity

Al-foam filled composite panels have enormous potential for application as light weight structural members as well as the energy absorber during crushing. In such applications the mechanical properties of foams are of paramount importance. In this study, Al alloy foams of composition Al-3 wt. %Si-2%Cu-2%Mg were produced using powder metallurgical method. Mechanical properties of foams of different density were measured using the uni-axial compression test and the measured properties such as elastic modulus and strength were compared with those of other existing commercial foams. The newly produced (Al-3%Si-2%Cu-2%Mg alloy) foams showed the elastic modulus and strength similar or sometimes higher than those of the other existing commercial foams. The electrical conductivity of the foams was measured and was found to follow a power law relationship, with an exponent value of 1.5, with the relative density. A set of mathematical relationships were deduced between electrical conductivity and various compressive properties of Al-foams with an aim to propose a nondestructive method for obtaining the elastic modulus, the compressive strength and the densification strain of foams using electrical conductivity. The curves obtained from derived relationships fit very well with the experimental results.