Calculation of thermodynamic properties of Mg-RE (RE = Sc, Y, Pr, Nd, Gd, Tb, Dy, Ho or Er) alloys by an analytic modified embedded atom method

Using the analytic modified embedded atom method (MEAM), the embedding, pot ential and modifying functions for the Mg and rare earth (RE) metals (RE = Sc, Y, Pr, Nd, Gd, Tb, Dy, Ho and Er) are presented. The thermodynamic prop erties, such as the dilute-limit heats of solution, enthalpies of formation of disordered solid solutions and intermetallic compounds, for the binary Mg-RE alloys are calculated The obtained results are in good agreement with the available experimental data and with the results calculated using Mied ema theory. The calculations of the enthalpies of formation of Mg3RE, Mg2RE , MgRE, MgRE2 and MgRE3 with various ordered structures (DO3, DO19, Ll, C15 , MoPt2, B2, Wl and L1(0)) indicate that the trends in the structural stabi lity can be interpreted directly in terms of the formation energy. Moreover , the lattice constants and volume contractions of alloys with various comp ositions are determined based on the relation between the formation energy and the interatomic distance. The correlation between the enthalpy of forma tion and volume contraction for intermetallic compounds is discussed.