SUBSOLIDUS PHASE-RELATIONS OF THE LA-FE-AL TERNARY-SYSTEM

The subsolidus phase relations of the La-Fe-Al ternary system have bee n investigated by X-ray powder diffraction. In this ternary system, th ere exist six kinds of ternary compounds and their solid solutions, i. e. A (La/Fe/Al (at.%)=10/12/78), B (36/44/20), LaFe4Al8, LaFe13-xAlx ( 2.34 less than or equal to x less than or equal to 7.28), La2Fe7Al10 a nd LaAl2-xFex (0 less than or equal to x less than or equal to 0.4). A and B are two kinds of new ternary compounds with unknown crystal str uctures. For the LaFe13-xAlx solid solution with cubic NaZn13-type str ucture, the solid solubility has been determined by a parametric metho d. The ternary system can be divided into 17 three-phase and four two- phase regions. The subsolidus phase relations of the La-Fe-Al ternary system are presented.