effect of fe additive on plastic deformation for crush-boxes with closed-cell metal foams, part i: al-composite foam compression response

abstractin this paper, we investigate effect of fe–intermetallic compounds on plastic deformation of closed-cell composite aluminum foam as filler of thin-walled tubes. however, deformation of the aluminum foam-filled thin-walled tubes as crushed-box will be presented in part (ii). composite foams of alsi7sic3 and alsi7sic3-(fe) as closed cell were synthesized by powder metallurgy foaming method. macro and micro structures of the produced foams revealed a non-homogenous cell dependent on fe-rich intermetallic compounds. the cellular structure of alsi7sic3 foam shows a non-uniform and small size of bubbles with a few central big voids in comparison with the alsi7sic3-(fe) foams. analysis of edax results show, there are (α+β)-fe- intermetallic compound within foams with fe < 2 wt. %, and (α+δ)-fe-intermetallic compound for the foams with fe > 2 wt. %, which presence of them, depended on the cooling rate during solidification of liquid foams. the uniaxial compressive stress–strain curves of the filled thin-walled tubs with the composite closed cell foams will be investigated in next part. the stress-strain curve of the alsi7sic3 foam shows a smooth plastic deformation behavior in the plastic region, throughout the compression tests. however with increasing the weight percent of fe from 1 up to 3%, the curve shows some variety at the slope of curves within the plastic zone. results shown all of the compression response is due to the micro-porosity in plateau region and presence of the fe-al-si-intermetallic within the cells wall that both them have the role of a stress concentration point during compressive loading.