( 1. 南京理工大学 材料科学与工程系, 南京 210094；
2. 东南大学 材料科学与工程系， 南京 210096)
摘 要: 分析了Al-TiO2系XD合成铝基复合材料的反应机理。 研究表明： Al与TiO2之间可自发进行强放热反应， 燃烧温度随增强相体积分数的增加而增加， 在增强相体积分数为50％时， 燃烧温度已达1 960 K， 远高于Merzhanov 的经验判据值1 800 K； 反应产物Al2O3是由液态Al与固态TiO2直接反应产生的， 呈细小颗粒状， 偏聚于基体颗粒的界面； Al3Ti是活性Ti原子扩散穿过反应层进入铝液与液态Al结合生成的， 呈短棒状， 分布相对均匀； 影响反应速率的主要因素有： TiO2颗粒尺寸、燃烧温度、 反应活化能、 反应界面面积等。
关键字: 复合材料； 活化能； 加热速率； 热扩散反应
（ 1. Department of Materials Science and Engineering,
Nanjing University of Sciences and Technology, Nangjing 210094, China;
2. Department of Materials Science and Engineering,
Southeast University, Nangjing 210096, China）
Abstract: The reactive mechanism of the composites synthesized by XD method in the Al-TiO2 system was analyzed. The thermodynamic results indicate that the reactions between TiO2 and Al carry through spontaneously with high quantity of exothermic heat. The combustion temperature increases with promoting the volume fraction and exceed Merzhanov experience criterion which is about 1 800 K when the reinforcement volume fraction is higher than 50%. The combusted products consist of particulate Al2O3 and stick Al3Ti. The Al2O3 particulates are formed directly by the reaction between Al and TiO2 and accumulated at grain interfaces of the matrix. The stick Al3Ti is formed by the reaction between Al atoms and active titanium diffused from the reaction region of Al-TiO2 and distributes uniformly in the matrix. The main factors influencing the reaction velocity of Al-TiO2 system are the size of TiO2 powders, combustion temperature, reaction activation energy, area of the reaction interface etc.
Key words: composites; active energy; heating rate; exothermic dispersion reaction
