稀土元素在Al中固溶度亚稳扩展研究

采用锤—砧技术制备了厚0.04—0.06mm快速凝固Al—RE(RE=Y,La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Er,Yb)合金箔试样,冷却速度达10~6K/s,用点阵参数法测得上述稀土元素在Al中亚稳扩展固溶度分别为0.4,0.15,0.21,0.21,0.3,0.5,0.1,0.6,0.65,0.7,0.75和0.2at.—%测定了Al—轻稀土(包括Eu)系中第二相是Al_4RE;Al—重稀土(包括Y)系中第二相是Al_3RE,原子尺寸因素是控制RE在Al中固溶度亚稳扩展的主要因素。

METASTABLE EXTENSION OF SOLID SOLUBILITY OF RARE EARTH ELEMENTS IN Al

The splat foils, 0.04--0.06 mm thick, of Al--RE (RE=Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Er, Yb) binary alloys were made by arc--melting and hammer--anvil technique at cooling rate in 10~6 K / s order of magnitude. The metastable extended solid solubilities of these RE elements have been evaluated by measurements of the lattice spacings of the rapidly solidified Al--RE alloys, they are 0.4, 0.15, 0.21, 0.21, 0.3, 0.5, 0.1, 0.6, 0.65, 0.7, 0.75, 0.2 at.--% for above mentioned individual RE metal, respectively. The secondary phase in rapidly solidified Al--RE alloys was identified to be Al_4RE for alloys containing light RE and Eu and Al_3RE for alloys containing heavy RE and Y. Some factors influencing the extension of solid solubility of Al--RE alloys were discussed.