The Effect of Fe Additive on Plastic Deformation of Crush-Boxes

The brass tubes with foam cores of AlSi7SiC3, AlSi7SiC3Fe1 and AlSi7SiC3Fe3 were produced as the crush-boxes with circle and square cross-section. Then axial compressive behavior and energy absorption capability of the foam-filled tubes were investigated during the quasi-static progressive plastic buckling. The uniaxial compressive stress–strain curves of the foam-filled brass tubes exhibited that the compressive stress enhanced smoothly with the increase of the strain and no stress oscillations occurred in the plastic deformation region throughout the tests. The yield stress and the elastic modulus of the foam-filled brass tubes slightly decreased with the increase of Fe wt. % in the foam cores. Moreover, with the increase of Fe powder from 1wt. % to 3wt. %, the absorption energy of the foam-filled brass tubes decreased slightly dependent on the tubes crosssection. The strain-hardening exponent of the tubes with the Al7Si -3SiC-(+Fe) foam cores were found to be lower than the tubes with the Al7Si-3SiC foam cores without Fe. However, the increase of Fe powder from 1wt. % to 3wt. % caused the approximate elimination of strainhardening and the plastic deformation behavior tends to be approximated to an ideal-plastic behavior up to the densification strain. The results indicate that all of the compression responses are due to the Micro and Macro-defects within the foams cellular structure as well as the tubes cross-section geometry.