Dynamic compression properties of porous aluminum with functionally graded pore structures

Functionally graded (FG) porous aluminum (Al), consisting of a high porosity layer and low porosity layer in a single porous Al, was fabricated by a friction stir welding (FSW). From X-ray computed tomography (CT) observations of the pore structures of fabricated FG porous Al, it was found that the fabricated FG porous Al had two layers with high porosity of large pore diameter layer and low porosity of small pore diameter layer. From compression tests of the fabricated FG porous Al, the deformation started from the high porosity layer then spread to the low porosity layer. The stress-strain curves obtained in the dynamic compression tests revealed that the stress of the plateau region was lower during the deformation of the high porosity layer than that during the deformation of the low porosity layer. The stresses and absorbed energies in those two plateau regions during such deformations were almost the same as those of the uniform porous Al.