Wear properties of the composites fabricated by exothermic dispersion reaction synthesis in an Al-TiO2-B2O3 system

The aluminum matrix composites with different B2O3/TiO2 mole ratios have been fabricated by exothermic propagation method in an Al-TiO2-B2O3 system. The dry sliding wear characteristics of the composites have been investigated by using a pin-on-disc wear tester at ambient temperature. The variation of the cumulative volume loss with sliding distance has been found to be linear for the composites. The wear rate increases with the increase in sliding velocity, and when the sliding velocities increases to about 0.9 m/s, the wear rate increases to a maximum value and then decreases with further increase in sliding velocity. The wear resistance of the composites is improved by increasing the B2O3/TiO2 mole ratios under the same wear test conditions. Without the B2O3, the reinforcements of the composite are composed of α-Al2O3 grains and Al3Ti rods, and the composite exhibits poor wear characteristics. But when adding the B2O3, the wear resistance of the composites is improved significantly due to the decrease of the amount of Al3Ti rods, and the increase of TiB2 particles, and the refinement of the matrix grains and the great improvement in the mechanical properties of the composites. When the B2O3/TiO2 mole ratio is increased up to 1, there is no Al3Ti rod existing in the composites and the composites exhibit good wear resistance.