Phase diagram of Sm-Nd-Fe ternary system

Phase equilibria of the Sm-Nd-Fe ternary system were determined in an isothermal section of 500 °C and vertical sections of SmFe2-NdFe2 and (Sm0.86Nd0.12)Fex (1.6≤x≤2.4) by optical microscopy, X-ray diffraction analysis, electron probe microanalysis (EPMA), and differential thermal analysis (DTA) techniques. There are four intermetallic phases: (Sm,Nd)Fe2, (Sm,Nd)Fe3, (Sm,Nd)5Fe17 and (Sm,Nd)2Fe17 in the Sm-Nd-Fe ternary system, and no (Sm,Nd)6Fe23 phase exists in this system. The isothermal section of 500 °C possesses 7 single-phase regions, 8 two-phase regions, and 4 three-phase regions. The vertical section of SmFe2-NdFe2 contains 2 single-phase regions, 4 two-phase regions, and 7 three-phase regions, and that of (Sm0.88Nd0.12)Fexconsists of 2 single-phase regions, 5 two-phase regions, and 2 three-phase regions. The peritectic temperatures for (Sm1-xNdx)Fe2 alloys decrease with increasing the Nd content when x≤0.5, and the substitution of Nd for Sm makes the stability of (Sm,Nd)Fe2 phase decrease.