Effects of B4C particles on Al-TiO2 reaction in Al matrix composite

In this study, composites were produced using powder metallurgy with Al-TiO2 and Al-TiO2-B4C as raw materials, and the impact of B4C on the reaction between Al and TiO2 was investigated. Hot-pressing was employed at temperatures of 580 degrees C, 600 degrees C, 620 degrees C, and 640 degrees C to fabricate the composites, followed by analysis of their microstructure and mechanical properties. The results revealed that at a temperature of 580 degrees C, Al3Ti and Al2O3 were formed in the Al-TiO2 composite system, and when the hot-pressing temperature reached 620 degrees C, all TiO2 within the matrix was completely consumed in the reaction with Al. In contrast, for the Al-TiO2-B4C composite system, B4C exhibited a noticeable inhibiting effect on the reaction. At a hot-pressing temperature of 580 degrees C, no discernible reaction occurred between TiO2 and the matrix; while at temperatures of 600 degrees C, 620 degrees C, and 640 degrees C, only a small amount of Al3Ti and Al2O3 appeared in the matrix. Consequently, the strength of composites fabricated by Al-TiO2 increased with increasing hot-pressing temperature; whereas for composites made from AlTiO2-B4C hot-pressed at different temperatures showed similar strengths.