Synthesis of Al₂O₃/Ti₃Al composites by in-situ displacement reactions

Synthesis of Al₂O₃/Ti₃Al composites by in-situ displacement reactions

The employment of aluminothermic reactions of displacement as an alternative for the production of Al₂O₃/Ti₃Al composite materials has been investigated. Compacted samples from an intensely ground mixture of powders of TiO₂+Al₂O₃ +Al were sintered at 1500ºC during 1 hour by hot pressing in an argon atmosphere. The TiO₂ is used as predecessor to generate in-situ Al₂O₃ via its reduction by means of metallic Al. Al reacts also in a simultaneous way with the reduced titanium to form an intermetallic alloy of the type TixAly. The Al₂O₃ employed in the precursor materials is used as a way for the dissipation of the heat build-up during the aluminothermic reduction of the TiO₂. The results of the characterizations indicate that Al₂O₃- based composite materials were obtained with reinforcement particles of TixAly. The microstructure of these materials is dense, fine and homogeneous. The preliminary characterization of the microstructure and its composition features subsequent to the cycle of in-situ processing are presented here.

The employment of aluminothermic reactions of displacement as an alternative for the production of Al₂O₃/Ti₃Al composite materials has been investigated. Compacted samples from an intensely ground mixture of powders of TiO₂+Al₂O₃ +Al were sintered at 1500ºC during 1 hour by hot pressing in an argon atmosphere. The TiO₂ is used as predecessor to generate in-situ Al₂O₃ via its reduction by means of metallic Al. Al reacts also in a simultaneous way with the reduced titanium to form an intermetallic alloy of the type TixAly. The Al₂O₃ employed in the precursor materials is used as a way for the dissipation of the heat build-up during the aluminothermic reduction of the TiO₂. The results of the characterizations indicate that Al₂O₃- based composite materials were obtained with reinforcement particles of TixAly. The microstructure of these materials is dense, fine and homogeneous. The preliminary characterization of the microstructure and its composition features subsequent to the cycle of in-situ processing are presented here.