Influence of the obtaining method on the compactness of AlMg10-SiCp ultralight composite

Abstract

The research was carried out on composite materials based on AlMg10-SiCp. This metallic ultralight materials were obtained by two methods: butane bubbling method and the soluble salt method. We chose different amounts of SiCp (5, 10 and 15%), the particles size being about 120 micrometers. The A method involves a forceful agitation of the melt aluminium alloy and SiC mixture, combined with gas bubbling (we used CH4 as the reactive gas). Method B involves the dissolution in water of the sodium chloride contained in the AlMg10-SiC composite after solidification of the metallic material. The occurrence of NaCl in the structure of the material is due to the introduction of sodium chloride and silicon carbide powders mixture in the molten material, which was very vigorously stirred. The A method leads to a cellular structure (small and medium size open and semi-open cells) of the composite and the B method to a porous one, like metal foams (semi-open cells). The increase of SiC percentage determinate the increase of the composite porosity, no matter of used method of achievement. The phenomenon can be explained by porosity increasing of those materials, equalization in cell size and tendency to uniform distribution of cells in the composite volume. As expected, the relative porosity of these composites increases with the silicon carbide percentage, reaching a maximum of 47% for AlMg10-15% SiC composite, obtained by the soluble salts method.