Pressurless infiltration into preformed SiCp by Al-Si alloys

For the production of partially composed metal matrix composites, namely discontinuous MMCs, using a casting process, the interpenetrated phase composites with SiC particles were fabricated by pressureless infiltration using molten Al-Si alloys. This process is based on a wetting phenomenon, therefore, we discussed the technique based on the reactive wetting. The SiC particles coated by diluted water glass were sintered in a mullite Tammann tube and simultaneously infiltrated with molten Al-Si alloys in air at 1173 similar to 1573K. As for the improvement of the wettability between the SiC and the liquid aluminum alloy, Fe3O4 powder was mixed with the water glass due to the thermit reaction between Fe3O4 and molten aluminum alloy. In some experiments, pure aluminum powder was placed on the sintered SiCp to increase the interfacial area and the chemical reaction between the sintered SiCp and the melt. By combining these conditions, we succeeded in the complete infiltration without pressure at 1173K.