Morphology and Elastic Properties of Aluminum Foams Produced by a Casting Technique

AA6101 aluminum foams (composition in wt.%: Al-0.6 Mg-0.5 Si) were fabricated by using a directional solidification technique. The 3-D morphology of the foams was examined using synchrotron x-ray tomography and the results revealed relatively uniform, open-celled structures. The mechanical (compression) behavior of the foams was also characterized. The stress-strain curves exhibited a typical three-stage behavior: elastic, nearly-perfect plastic (i.e., with a stress plateau), and densification. The elastic moduli of a 10%-dense foam in the directions that are transverse and parallel to the solidification direction were measured to be 630 and 670 MPa, respectively. Theoretical calculations of the modulus using a FEM method with the element-by-element (EBE) formalism were also carried out. The calculated values of approx570 and 635 MPa compared favorably with the experimental data.