Thermodynamic assessment of the Ta–Ge system supported by ab initio calculations

The Ta–Ge system was thermodynamically modeled for the first time using the CALPHAD method incorporating both literature-derived phase equilibria data and new enthalpy of formation values for the intermetallic compounds. Density Functional Theory (DFT) calculations were employed to accurately determ...

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Bibliographic Details
Published in:Calphad 2024-03, Vol.84, p.102669, Article 102669
Main Authors: Pinto da Silva, Antonio Augusto Araujo, Ferreira, Pedro Pires, Dorini, Thiago Trevizam, Coelho, Gilberto Carvalho, Nunes, Carlos Angelo, Eleno, Luiz Tadeu Fernandes
Format: Article
Language:English
Subjects:
Calphad
Density functional theory
Germanides
Ta–Ge system
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Summary:The Ta–Ge system was thermodynamically modeled for the first time using the CALPHAD method incorporating both literature-derived phase equilibria data and new enthalpy of formation values for the intermetallic compounds. Density Functional Theory (DFT) calculations were employed to accurately determine enthalpy of formation values for key Ta–Ge compounds. The stable intermetallic phases (i.e., αTa3Ge, βTa3Ge, βTa5Ge3, and TaGe2) were described as stoichiometric phases while the Liquid (L), Ta-rich solid solution (BCC-A2), and Ge-rich solid solution (Diamond-A4) were modeled as solution phases using the Compound Energy Formalism. Excess terms were described by the Redlich-Kister polynomials. The present thermodynamic model accurately describes phase equilibria and thermodynamic data, providing a reliable guide for designing alloys containing Ta and Ge.
ISSN:0364-5916
1873-2984
DOI:10.1016/j.calphad.2024.102669