First-principles calculations and thermodynamic re-modeling of the Hf-W system

Alyson C. Lieser, Chelsey L. Zacherl, Arkapol Saengdeejing, Zi-kui Liu, Laszlo J. Kecskes

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

An integrative approach coupling first-principles calculations and the CALculation of PHAse Diagram (CALPHAD) method provides a more thermodynamically accurate model of the Hf-W system when compared to previous models. A two-sublattice model is used for describing the solid solubility of the HfW 2 Laves phase. The modeling of the Laves phase includes input from first-principles total energy calculations and predictions of finite temperature properties from the Debye-Grüneisen model. In addition, first-principles calculations performed on hcp and bcc special quasirandom structures (SQS) predicted a positive enthalpy of mixing in both solid solution phases. Predicting the finite temperature properties of bcc SQS with the Debye-Grüneisen model was necessary to balance the positive, asymmetric enthalpy of mixing found in the bcc solid solution. The model produced by the coupling of CALPHAD modeling with first-principles calculations agrees well with experimental data. It also reproduces the Hf-W phase diagram with fewer parameters than previous models, which were created without the aid of first-principles calculations.

Original languageEnglish (US)
Pages (from-to)92-99
Number of pages8
JournalCalphad: Computer Coupling of Phase Diagrams and Thermochemistry
Volume38
DOIs
StatePublished - Sep 1 2012

All Science Journal Classification (ASJC) codes

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

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