In situ synthesis of Al2O3 particulate-reinforced Al matrix composite by low temperature sintering

The powder mixture of Al-10 wt.% SiO2 was selected as a research system. Compared with an as-mixed powder, the phase structure and microstructure of an as-milled powder was investigated, and the temperature of the displacement reaction in the two kinds of powder was determined by thermal analysis. The preforms of the two kinds of powder were sintered based on the result of thermal analysis. The results indicate that the particle size of the Al-SiO2 powder was refined greatly after 4 h of high energy ball milling, and diffusion couples were formed due to SiO2 particles embedded in the Al matrix. The displacement reaction did not occur between Al and SiO2 for the as-mixed powder, while it occurred in the range of 560–680°C for the as-milled powder. For the as-milled powder, an aluminum matrix composite reinforced with Al2O3 particles, which were homogeneously distributed in the Al matrix, can be fabricated by sintering at 640°C for 2 h.