Fabrication of two layers porous aluminum varying porosity by friction powder sintering process and its compression properties

Two layers porous aluminum (Al), consisting of a high porosity layer and low porosity layer in a single porous Al, was fabricated by a friction powder sintering process based on the sintering and dissolution process by varying NaCl volume fraction φ. In X-ray computed tomography (CT) images, two layers with φ=80% (high porosity) and φ=60% (low porosity) were clearly observed in the single porous Al. In compression tests of the fabricated two layers porous Al, the deformation started from the φ= 80% layer then spread to the φ=60% layer. The stress-strain curves obtained in the compression tests revealed that the stress of the plateau region was lower during the deformation of the φ=80% layer than during the deformation of the φ=60% layer. The stresses in the plateau region during such deformations were almost the same as those of the uniform φ=80% and φ=60% porous Al. Consequently, it was shown that the two layers porous Al with varying porosity exhibited high and low plateau stresses with almost the same plateau stresses as uniform porous Al.