( 1. 南京理工大學(xué) 材料科學(xué)與工程系, 南京 210094；
2. 東南大學(xué) 材料科學(xué)與工程系， 南京 210096)
摘 要: 分析了Al-TiO2系XD合成鋁基復(fù)合材料的反應(yīng)機(jī)理。 研究表明： Al與TiO2之間可自發(fā)進(jìn)行強(qiáng)放熱反應(yīng)， 燃燒溫度隨增強(qiáng)相體積分?jǐn)?shù)的增加而增加， 在增強(qiáng)相體積分?jǐn)?shù)為50％時(shí)， 燃燒溫度已達(dá)1 960 K， 遠(yuǎn)高于Merzhanov 的經(jīng)驗(yàn)判據(jù)值1 800 K； 反應(yīng)產(chǎn)物Al2O3是由液態(tài)Al與固態(tài)TiO2直接反應(yīng)產(chǎn)生的， 呈細(xì)小顆粒狀， 偏聚于基體顆粒的界面； Al3Ti是活性Ti原子擴(kuò)散穿過反應(yīng)層進(jìn)入鋁液與液態(tài)Al結(jié)合生成的， 呈短棒狀， 分布相對(duì)均勻； 影響反應(yīng)速率的主要因素有： TiO2顆粒尺寸、燃燒溫度、 反應(yīng)活化能、 反應(yīng)界面面積等。
關(guān)鍵字: 復(fù)合材料； 活化能； 加熱速率； 熱擴(kuò)散反應(yīng)
WU Shen-qing
（ 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
