Microstructure and Physical Properties of AlMg/Al2O3 Interpenetrating Composites Fabricated by Metal Infiltration into Ceramic Foams
This work presents aluminium alloy-alumina (AlMg5/Al2O3) composites, where both phases are interpenetrating through-out the microstructure. Ceramic preforms for metal infiltration were produced by a new method of manufacturing of porous ceramics known as gelcasting of foams. Porous ceramics fabricated by this method is characterized by a continuous network of spherical cells interconnected by circular windows. Alumina (Al2O3) preforms used for infiltration process, were characterized by 90% porosity. The median diameter of spherical cell was 500 μm, while the median diameter of windows was 110 μm.
A direct pressure infiltration process was used to infiltrate the preforms with an AlMg5 alloy resulting in an interpenetrating microstructure. Due to the open cell structure of the Al2O3 foams, macropores in alumina preform were completely filled by metal. Microstructural characterization of the composites revealed a special topology of skeleton and good integrity of metal/ceramic interface. The density of AlMg5/Al2O3 composites was 2.71 g/cm3, while the porosity was less than 1%.