PRESSURLESS INFILTRATION INTO PREFORMED SiC_P BY Al-Si ALLOYS

摘要

For the production of partially composed metal matrix composites, namely discontinuous MMCs, using a casting process, the interpenetrated phase composites with SiC particles woe 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 approx 1573K. As for the improvement of the wettability between the SiC and the liquid aluminum alloy, Fe_3O_4 powder was mixed with the water glass due to the thermit reaction between Fe_3O_4 and molten aluminum alloy. In some experiments, pure aluminum powder was placed on the sintered SiC_P to increase the interfacial area and the chemical reaction between the sintered SiC_P and the melt. By combining these conditions, we succeeded in the complete infiltration without pressure at 1173K.