快速凝固偏晶合金的显微结构

Microstructure of Rapidly Solidified Monotectic Alloys

采用雾化快速凝固技术制备了ＡｌＰｂ二元偏晶合金。对合金的显微结构分析结果表明，在快速凝固条件下，偏晶合金中的第二相形态从带条状转变为颗粒状。随冷速的增加，第二相在基体中的分布更趋均匀、细化；随冷速的降低和第二相含量的增加，第二相趋于分布于材料的表面。本文从凝固过程的凝固速度和固／液界面对第二相液滴的界面排斥对上述现象进行了解释。

Al Pb binary monotectic alloys were prepared using the rapidly solidified gas atomization technology. Microstructure analysis results showed that, in the condition of rapid solidification, the second phase morphology of monotectic alloys transited from rods into particles. With increasing of solidification rates, a much even and finer distribution of second phase particles appeared. Whereas with decreasing of solidification rates and increasing of amount of the second phase, much of the second phase particles tended to distribute on the surface of atomized powders. Such phenomena were analyzed from the solidification rates of particles and the surface repellence to the droplets at the solid/liquid interface during solidification process.