Fabrication of porous metals via selective phase dissolution of an Al-Cu alloy

Abstract

Through free corrosion in sodium hydroxide, a new porous material was successfully fabricated by removing a single phase of the aluminum-copper alloy. This selective phase dissolution was performed for the eutectic composition of the aluminum-copper binary system and additionally for two hypereutectic compositions. The porosity of the material depends on the microstructure formed in the solidification process. For this, several solidification methods were analyzed in order to define the most convenient in terms of uniformity and refinement in the pore and ligament sizes. The concentration of the solution was determined by observing the effectiveness of the process during and after the corrosion, when the 10% v/v aqueous solution of sodium hydroxide was used better results were observed. The porosity was calculated after the selective dissolution through analysis of images obtained from a scanning electron microscope. In addition, the average pore and ligament size was measured for each composition. Finally, the effectiveness of the process was verified using x-ray diffraction, which showed that under the proposed methodology there was complete removal of one of the phases of the alloy.