Abstract: Al2O3 and Al 3Ti reinforced aluminum matrix composites were prepared by means of exothermic dispersion (XD) in situ synthesis technique. Its kinetic mechanism was also discussed. The results show that Al-TiO2 system can be reacted in very short time. The reaction is propagated in combustion wave. It is also shown that aluminum initially react with TiO2 to form Al2O3 and reduced Ti by X ray diffraction and scanning electroric microscopy. Then the reaction between reduced Ti and aluminum is subsequently followed. The Al2O3 and Al3Ti take the shapes of equiaxed particle and block respectively. A certain heating rate and content of aluminum are needed, if thermal explosion occurs commonly in the Al-TiO2 system. The aluminum content and green density also have influences on the combustion temperature and bulk shrinkage. The combustion temperature would be lower for higher aluminum content, but its bulk shrinkage would be higher.
Al2O3 and Al_ 3Ti reinforced composites prepared by exothemic dispersion synthesis technology
Abstract:
Al 2O 3 and Al 3Ti reinforced aluminum matrix composites were prepared by means of exothermic dispersion (XD) in situ synthesis technique. Its kinetic mechanism was also discussed. The results show that Al TiO 2 system can be reacted in very short time. The reaction is propagated in combustion wave. It is also shown that aluminum initially react with TiO 2 to form Al 2O 3 and reduced Ti by X ray diffraction and scanning electroric microscopy. Then the reaction between reduced Ti and aluminum is subsequently followed. The Al 2O 3 and Al 3Ti take the shapes of equiaxed particle and block respectively. A certain heating rate and content of aluminum are needed, if thermal explosion occurs commonly in the Al TiO 2 system. The aluminum content and green density also have influences on the combustion temperature and bulk shrinkage. The combustion temperature would be lower for higher aluminum content, but its bulk shrinkage would be higher.