The refinement mechanism of aluminum matrix composites fabricated by exothermic dispersion method in Al-TiO2-B reaction system

The refinement mechanism of composites fabricated by exothermic dispersion method in Al-TiO2-B reaction system has been studied. The experimental results indicate that without boron, the combustion synthesized phases of the Al-TiO2 system are Al2O3 and Al3Ti, the fine Al2O3 particles exist at the interface of the matrix grains and the Al3Ti phase has the rod shape; with adding boron into the Al-TiO2 System, the amount of Al3Ti phase decreases and disappears in the system with the B/TiO2 mole ratio of 2. At that time, the TiB2 phase appears, the matrix grains are significantly refined and the distribution of Al2O3 particles is more uniform.