Contribution of first-principles energetics to Al-Mg thermodynamic modeling

Yu Zhong, Mei Yang, Zi-kui Liu

Research output: Contribution to journalArticle

80 Citations (Scopus)

Abstract

Despite numerous investigations, all previous efforts on thermodynamic modeling of Al-Mg have suffered from inaccurate energetics of solid phases. In the present work, the first-principles calculations were performed using VASP based on the pseudo-potentials and a plane wave basis set. The enthalpies of formation of the ε-Al30Mg23 phase, end-members of the γ-Al12Mg17 phase, and three laves phases at the Al2Mg composition were calculated at 0 K. Special quasi-random structures (SQS's) were used to mimic random fcc and hcp solution phases, and their enthalpies of mixing were predicted by first-principles calculations. The Al occupancy in the γ-Al12Mg17 phase is also studied by first-principles calculations, and the sublattice model (Mg)5(Al,Mg)12(Al,Mg)12 was verified as the proper model to describe the γ-Al12Mg17 phase. The complete thermodynamic description of the Al-Mg binary system was evaluated by this combined CALPHAD/first-principles calculations approach and was shown to be in a good agreement with experimental data with better defined energetics of solid phases than the previous modeling.

Original languageEnglish (US)
Pages (from-to)303-311
Number of pages9
JournalCalphad: Computer Coupling of Phase Diagrams and Thermochemistry
Volume29
Issue number4
DOIs
StatePublished - Dec 1 2005

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Thermodynamics
Enthalpy
Chemical analysis

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Chemical Engineering(all)
  • Computer Science Applications

Cite this

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abstract = "Despite numerous investigations, all previous efforts on thermodynamic modeling of Al-Mg have suffered from inaccurate energetics of solid phases. In the present work, the first-principles calculations were performed using VASP based on the pseudo-potentials and a plane wave basis set. The enthalpies of formation of the ε-Al30Mg23 phase, end-members of the γ-Al12Mg17 phase, and three laves phases at the Al2Mg composition were calculated at 0 K. Special quasi-random structures (SQS's) were used to mimic random fcc and hcp solution phases, and their enthalpies of mixing were predicted by first-principles calculations. The Al occupancy in the γ-Al12Mg17 phase is also studied by first-principles calculations, and the sublattice model (Mg)5(Al,Mg)12(Al,Mg)12 was verified as the proper model to describe the γ-Al12Mg17 phase. The complete thermodynamic description of the Al-Mg binary system was evaluated by this combined CALPHAD/first-principles calculations approach and was shown to be in a good agreement with experimental data with better defined energetics of solid phases than the previous modeling.",
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Contribution of first-principles energetics to Al-Mg thermodynamic modeling. / Zhong, Yu; Yang, Mei; Liu, Zi-kui.

In: Calphad: Computer Coupling of Phase Diagrams and Thermochemistry, Vol. 29, No. 4, 01.12.2005, p. 303-311.

Research output: Contribution to journalArticle

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