Thermodynamic assessment of Au–Ho and Au–Tm binary systems

Phase relationships in Au–Ho and Au–Tm binary systems have been thermodynamically assessed by using the CALPHAD technique. The existing thermodynamic descriptions of the systems were improved by incorporating the ab initio calculated enthalpies of formation of the intermetallic compounds (IMCs) to the assessment. All the binary intermetallic compounds were treated as stoichiometric phases, while the solution phases, including liquid, fcc, and hcp, were treated as substitutional solution phases. Furthermore, the excess Gibbs energies were formulated with the Redlich–Kister polynomial function. As a result, two self-consist thermodynamic data sets for describing the Au–Ho and Au–Tm binary systems have been obtained.

► The lattice stability of the metastable Tm(fcc) and Ho(fcc) were calculated.
► The formation enthalpies for most of the compounds in Au–Ho were calculated.
► The formation enthalpies for most of the compounds in Au–Tm were calculated.
► Two sets of thermodynamic parameters for these two systems were obtained.