Solvus boundaries of (meta)stable phases in the Al-Mg-Si system: First-principles phonon calculations and thermodynamic modeling

H. Zhang, Y. Wang, S. L. Shang, C. Ravi, C. Wolverton, L. Q. Chen, Z. K. Liu

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

Using first-principles total energies and frozen phonon calculations, we predict the thermodynamic properties (enthalpies of formation and vibrational entropies) for three phases in the Al-Mg-Si system: the stable phase (β-Mg2Si), and two metastable precipitate phases (β - Mg18 Si10 and β - Mg5 Si6). The stable fcc / β and the metastable fcc / β and fcc / β phase boundaries are obtained from a combination of the Gibbs energy of the compounds determined from first-principles and the free energy of the Al-rich solid solution (fcc phase) taken from the literature. Predicted phase boundaries show good agreement with available phase stability measurements. The present work demonstrates the capability of first-principles calculations in predicting Gibbs energies of stable and metastable phases.

Original languageEnglish (US)
Pages (from-to)20-25
Number of pages6
JournalCalphad: Computer Coupling of Phase Diagrams and Thermochemistry
Volume34
Issue number1
DOIs
StatePublished - Mar 2010

All Science Journal Classification (ASJC) codes

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

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