The Effect of Sintering Temperature on the In-Situ Reaction Mechanism and the morphology of the reaction products of Al-TiO2

Aluminum matrix composites hybrid–reinforced with Al3Ti and Al2O3 particles were synthesized by in situ reaction of Al–15%TiO2 (mass fraction) via the exothermic dispersion method. The effects of sintering temperatures on the reaction mechanism and the morphology of reaction products of Al–15% TiO2 were investigated. The results show that the amorphous AlxOy is formed for the O in TiO2 diffusing into the Al in the solid–solid reaction stage. The diffusion ability of the O diffusing to the interface increases with the temperature increasing , and the α–Al2O3 formed at the interface transforms from α–Al2O3 layer into regularly–shaped particles. Al and Ti atoms interdiffuse through the oxide layer. α–Al2O3 particles are formed as Al atoms diffusing into TiO2, and Al3Ti is formed as Ti atoms diffusing into Al. Al3Ti rods are obtained when α–Al2O3 layere is formed at the interface, and near–spherical Al3Ti particles are obtained when α–Al2O3 particles are formed. Aluminum matrix composites hybrid–reinforced with Al3Ti and Al2O3 particles is synthesized at 1200 ℃. The highest microhardness of HV 148.08 and the optimal wear a wear rate of 1.23×10–4 kg·N–1·m–1 of the composite synthesized at 1200 ℃ are obtained.