Research Of Structure And Related Performance Of Self-reinforced Aluminum Titanate In Situ Synthesized By Solid State Reaction Via Mechanical Activation Process

This work is concentrated on the studies of low temperature synthesis and self-reinforced microstructure formation of aluminum titanate. Effect of mechanic activation on low temperature composition and effect of type or amount of additives, molding pressure, sintering temperature, holding time at the maximum temperature, heating rate and atmosphere on the microstructure of aluminum titanate were investigated. Mechanic properties of selected samples were measured.In the processing of mechanical activation, the grain size and crystal lattice of precursors reduced significantly and broadened. Anatase titania partially transformed into amorphous and Srilankite phases with nanometer level. The mechanical activation makes the activated powder mixtures more reactive, which leads to a higher internal energy and reduces the thermal barrier for the subsequent formation. Al₂TiO₅ materials with microcrack-free microstructure were prepared in lower temperature through controlling the grain size to less than critical sizeAl₂TiO₅–MgTi₂O₅ solid solutions obtained by reaction sintering benefits anisotropic grain growth of Al₂TiO₅, which increased the stabilization and improved mechanical performance of aluminum titanate. Eutectic reaction between copper oxide and titanium dioxide could enhance densification kinetics. Some hexagonal-flake grains formed in proper conditions. Doping of H3BO3 promoted densification with liquid phase sintering. It is found that the microstructure with a distinct bimodal size distribution of grain sizes could be prepared with co-doping of binary additives.In conclusion, the process of mechanic activation reduces the synthesized temperature of aluminum titanate. It is easy to prepare self-reinforced aluminum titanate with rod-like, hexagonal-flake or bimodal size distribution of grain sizes when doped with various additives. At the same time, a thorough analysis and discussion on the mechanism of anisotropic grain growth of aluminum titanate and its improved fracture toughness. Therefore, this research is valuable to the preparation of self-reinforced materials and the improvement of the mechanic properties of aluminum titanate.