摘要
以Ti、Al和TiO2混合粉的原位反应制备Al2O3颗粒增强TiAl基复合材料。利用热力学机理分析了制备该种材料的可行性;用扫描电镜观察了合成产物的组织形态;借助差热变化曲线,对Ti-Al-TiO2体系的反应过程进行了初步研究。结果表明,Ti-Al-TiO2体系的反应能够原位生成Al2O3颗粒增强的TiAl基复合材料;Al2O3颗粒分布在基体晶界处,随其含量增大,基体晶粒逐渐细化;铝熔化后首先开始了TiAl3的生成反应,由于TiO2的稀释作用,使它的放热峰与Ti-Al体系的主放热峰相比有所滞后,紧接着发生了Al-TiO2的还原反应,由于其激活能低而速度较快,因此较早完成;若Al-TiO2的还原反应未进行彻底,部分TiAl3将分解以提供铝液;最后发生了TiAl3向TiAl和Ti3Al相转变的过程。
In-situ Al2O3/TiAl base composites were fabricated by the chemical reaction with Ti, Al and TiO2 powders. The feasibility of the composite fabrication was analyzed by thermodynamic mechanism, the microstructures of the composites were observed by SEM, and the reaction process of Ti-Al-TiO2 composites was investigated by means of differential thermal analysis （DTA）. The results show that the reaction of Ti-Al-TiO2 composite can form TiAl based composites reinforced by Al2O3 particles;Al2O3 particles distribute along the grain boundary and the grain is refining with Al2O3 content increasing;after aluminum melts,TiAl3 forms reaction first, comparing to the main exothermic peak of Ti-Al system,the exothermic peak of TiAl3 lags because of TiO2 dilution,then there occurs the reaction of aluminum and TiO2 ,the reduction of TiO2 is completed earlier than reactions between Al and Ti due to faster reaction rate resulted from smaller activation energy. If the reduction of TiO2 can not complete thoroughly, a part of TiAl3 must be resolved in order to supply aluminum fluid. At last, there presents TiAl3 transformation to TiAl and Ti3Al phase.
出处
《金属热处理》
CAS
CSCD
北大核心
2009年第1期85-89,共5页
Heat Treatment of Metals
基金
陕西省教育厅专项科研项目(08JK240)
陕西理工学院引进人才科研启动项目(SLGQD0751)
