Thermodynamic Assessments Of Some RE-X Binary Systems

Rare earth metals have been used in many fields due to their excellent magnetic, electrical and optical properties.In particular,the intermetallic compounds formed between transition metals and rare earth elements are of particular importance for high performance functional materials,such as permanent magnet and hydrogen storage materials.In order to design new rare earth alloys,improve the alloy properties, optimize alloy compositions and processing,it is necessary to investigate the phase diagrams and thermodynamic data in rare earth alloys.In this paper,thermodynamic assessments of some RE-X binary phase diagrams were carried out using the CALPHAD method.Major research contents are listed as follows:(1) The phase equilibria of the Cu-X(Tm,Ho,Tb,B,Ta,Os,Re) binary systems have been thermodynamically optimized based on the available experimental data.A set of self-consistent and reasonable thermodynamic parameters is obtained for each binary system,which describes the Gibbs energies of the solution phases and the intermediate phases.(2) The phase equilibria of the Mo-X(Ce,Pr,Nd,Sm,Eu,Tb,Ho,Tm,Yb,Lu) binary systems have been thermodynamically optimized based on the available experimental data.A set of self-consistent and reasonable thermodynamic parameters is obtained for each binary system,which describes the Gibbs energies of the solution phases.(3) The phase equilibria of the Cr-X(Sm,Lu),V-X(Ho,Lu),Au-X(Rb,Mo) and Th-W binary systems have been thermodynamically optimized based on the available experimental data.A set of self-consistent and reasonable thermodynamic parameters is obtained for each binary system,which describes the Gibbs energies of the solution phases and the intermediate phases.The obtained thermodynamic parameters of each system in this work can be applied to establish the thermodynamic database of rare earth alloys.In addition,the calculated results in this work can provide important theoretical guidance on design of high performance rare earth alloys.