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

In this study, the effect of fe–intermetallic compounds on plastic deformation of closed-cell composite aluminum foam as the filler of thin-walled tubes is investigated. composite foams of alsi7sic3 and alsi7sic3-(fe) as a closed cell were synthesized through powder metallurgy foaming method. macro and micro structures of the produced foams revealed a non-homogenous cell which is 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. the analysis of edax (energy dispersive analysis of x-rays) indicate that 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. %, in which their presence depend on the cooling rate during the solidification of liquid foams. the stress-strain curve of the alsi7sic3 foam shows a smooth plastic deformation behavior in the plastic region, throughout the compression tests. however, by increasing the weight percent of fe from 1 up to 3%, the curve shows some variation at the slope of ln(σ)-ln(ε) curves within the plastic zone. the results obtained indicated that all of the compression response is due to the micro-porosity in plateau region and the presence of the fe-al-si-intermetallic within the cell wall revealed that both of them have the role of a stress concentration point during the compressive loading.