Effects of infiltration agent factors on spontaneous infiltration behavior in fabrication of magnesium matrix composites

Abstract

Experiments were carried out on the spontaneous infiltration of magnesium melt to powder bed, to find out an appropriate infiltration agent powder of which was mixed with reinforcements previously. In this work, TiO₂ (anatase and rut-ile), MnO, ZnO and CuO powders were tested as an infiltration agent, using SiC_p powder (average diameter was from 2 to 8 μm) as a reinforcement. In addition, to investigate the effect of particle diameter of infiltration agent on the spontaneous infiltration, the milled smaller SiO₂ of average diameter 1 μm was also tested. The infiltration was performed at 973 K under pure argon gas atmosphere for 1.2 ks holding time. Furthermore, infiltration velocity was also measured. It was found that only TiO₂ (anatase) could be used as an infiltration agent, and that the infiltration behavior to the powder bed mixed with anatase was different from that mixed with SiO₂ and affected also by matrix metal, pure magnesium or AZ91 alloy. The infiltration velocity in the case of anatase as a agent was lower than that in the case of SiO₂. The critical content of smaller SiO₂ agent for the occurrence of infiltration decreased, and the infiltration velocity increased by mixing the larger SiO₂.