Fabrication of Porous Metals with Unidirectionally Aligned Pores by Rod-Dipping Process

"Rod-dipping Process" was developed to simultaneously fabricate and strengthen porous metals with pore with unidirectionally aligned throughout their matrix. Carbon rods were dipped into a molten A6061 alloy, quenched, and processed by equal-channel angular extrusion (ECAE). The rods were subsequently removed, producing the porous metal throughout a metallic matrix. To determine the possibility of using our method to fabricate various porous metals, a theoretical equation was formulated for calculating the volume of hydrostatic pressure required for a molten metal to infiltrate the spaces between rods of various diameters and spaced at various intervals. The primary crystal was isotropic, and no reaction products were formed on the pore surfaces. Therefore, the crystal and pore growth directions could be independently controlled. By introducing an equivalent plastic strain of 1.2, the Vickers hardness values of the samples homogeneously increased to 1.5 times higher than that of the as-cast samples. Consequently, this method enabled us to fabricate porous metals with pore with unidirectionally aligned throughout their matrices and whose pore sizes, positions and volume fractions could be arbitrarily controlled. Furthermore, the metallic matrix could be simultaneously hardened by plastic deformation.