摘要
本文主要研究了Al TiO2 系XD合成铝基复合材料的反应产物Al3Ti的形貌及其演变的影响因素。研究表明Al TiO2 系反应产物由Al2O3 和Al3Ti组成,Al2O3 为细小颗粒,与铝液不润湿,偏聚于基体颗粒的界面;Al3Ti呈棒状,优先生长方向为<110>;随着增强相体积分数的增加,反应温度提高,活性Ti原子的扩散能力增强,扩散路程变短,有利于Al3Ti择优生长,但Al2O3 颗粒的浓度增加,使Ti原子的扩散阻力和Al3Ti的生长阻力同步增大,Al3Ti的择优生长倾向反而减弱,其形貌由棒状向块状演变;在纯铝液中Al3Ti的生长形貌为细长棒状,而在真空中则为薄片状;随着保温时间的延长,其轴向尺寸明显增大,径向尺寸增加不明显。
The Al3Ti morphology and its influence factors of the composites fabricated by XD (exothermic dispersion) method in Al-TiO2 reaction system are studied in the paper. The studied results indicated that reacted products of the Al-TiO2 system were consisted of Al3Ti and Al2O3. The Al2O3 phase with particulate shape segregated at the aluminum matrix regions due to its bad wetting with the matrix. The other phase Al3Ti in the stick shape was formed by Al and active Ti atoms that were produced by the reaction between liquid aluminum and TiO2, and its preferential growing direction was (110). With increase of reinforcement volume fraction, the diffusion distance and diffusion ability of the active Ti atoms became shorter and stronger respectively. But owing to increase of concentration of Al2O3 phase, the diffusion resistance of Ti atoms and growing resistance of the Al3Ti became higher. Therefore, the preferential growing tendency of Al3Ti phase became weaken and its shape changed from stick to block. The morphology of Al3Ti phase also changed with its growing circumstance, it was in the shape of slender stick and slice with growing in the pure liquid aluminum and vacuum state respectively. With the increase of keeping time, the length of Al3Ti stick became longer in evidence, but the radical dimension increased indistinctively.
出处
《人工晶体学报》
EI
CAS
CSCD
北大核心
2005年第2期233-237,232,共6页
Journal of Synthetic Crystals
基金
国家 863计划项目(No. 2002AA331010)
南京理工大学发展基金(AB96056)资助
