Thermodynamic description of the Ce-Mg-Y and Mg-Nd-Y systems

Abstract

Abstract The thermodynamic modeling and optimization of the Ce-Mg, Ce-Y, Mg-Nd, Nd-Y, Ce-Mg-Y and Mg-Nd-Y systems have been carried out by means of the CALPHAD technique. The solution phases, liquid, body-centered cubic, face-centered cubic, hexagonal close-packed and double hexagonal close-packed, were described by the substitutional solution model. The isostructural MgCe, MgNd and MgY phases with B2 structure form continuous range of solid solutions in the Ce-Mg-Y and Mg-Nd-Y ternary systems. The order-disorder transition between the solutions with A2 structure and compounds with B2 structure in the systems has been taken into account and thermodynamically modeled. The other compounds Mg2Y, Mg24Y5, Mg3R, Mg41R5, Mg2R and Mg12Ce (R = Ce and Nd) in the Mg-R-Y system exhibit different solubilities of the third component. A set of self-consistent thermodynamic descriptions of the Ce-Mg-Y and Mg-Nd-Y systems was obtained.