Thermodynamic analysis of phase equilibria in the Nd-Fe-Cu ternary system

Michitoshi Saeki, Yuji Horino, Luo Jinya, Masanori Enoki, Hiroshi Ohtani

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


A thermodynamic assessment of the Nd-Fe-Cu system was attempted using the CALPHAD method, to clarify an effect of Cu addition to the permanent magnets based on Nd2Fe14B phase. The regular solution model was applied to liquid phase and solid solutions. Intermediate compounds were described as stoichiometric phases. The formation enthalpy of σ(Nd6Fe13Cu) phase was evaluated using the first-principles calculation. The result was introduced to the optimization process with some experimental phase boundary data. In the calculated liquidus projection of the ternary system, it is characteristic that the two-phase separation of the liquid phase exists between Fe-rich and (Nd, Cu)-rich regions. The ternary eutectic reaction E1:( L)⇔βNdCu+(αNd)+σ occurs in the Nd-rich region and the reaction temperature is estimated about 508.6?.

Original languageEnglish
Pages (from-to)32-42
Number of pages11
JournalNippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals
Issue number1
Publication statusPublished - 2017


  • CALPHAD (calculation of phase diagrams) method
  • Grain boundary
  • Neodymium-iron-boron permanent magnets
  • Phase diagram
  • Thermodynamic analysis

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys
  • Materials Chemistry


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