Detailed Analysis of Closed-Cell Aluminum Alloy Foam Internal Structure Changes during Compressive Deformation

This paper proposes the new methodology for geometrical properties identification of step-wise deformed closed-cell aluminum alloy foam. The change of internal structure of cylindrical foam specimens during deformation is ex situ recorded by a micro computed tomography scanner. The geometry of five specimens is analyzed in un-deformed and several deformed states until 70% of engineering strain. The obtained CT images is used to construct the 3D computer models of un-deformed/deformed foam specimens. These are then subjected to an automated analysis of the geometrical properties of internal structure to determine the size, distribution, and orientation of the pores. The results provide the basis for further analysis of the variation in internal structure during the deformation process. The internal structure of un-deformed specimens exhibits a pore orientation dependent on the fabrication process. Significant changes of internal pore structure is observed during the deformation process, where the specimens with small spatial variation of porosity sustains larger strains until failure under compressive load. The specimens with larger spatial variation of porosity and larger pore concentrations disintegrate earlier.