Experimental Verification of Cell Shape-Collapse Relationships in Metallic Foams by Photoelasticity Method

Abstract

In the present study, the effect of cell morphology on mechanical properties in metallic foams with Al based closed cells was examined. AlSi8Mg0.8 alloyed metallic foam materials were produced by the Powder Metallurgy (PM) method. The elastic stresses and their distributions which were created by the compression load in the metallic foams, producing in similar density and different cell sizes were investigated by the photoelasticity method. The fracture and collapse mechanisms of the foaming materials, having the same density but different cell size and shape factor, exhibited discrepancy as well. The elastic stress concentrations and their distributions that were created by compression at the cell walls could be determined by the photoelasticity method. It was detected that the fringe orders in the photoelasticity images provided important and accurate information about the stress concentration areas at the foam walls. It was specified that the collapse at the end of the compression tests started mostly at these areas.