### 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 language | English (US) |
---|---|

Pages (from-to) | 92-99 |

Number of pages | 8 |

Journal | Calphad: Computer Coupling of Phase Diagrams and Thermochemistry |

Volume | 38 |

DOIs | |

State | Published - Sep 1 2012 |

### Fingerprint

### All Science Journal Classification (ASJC) codes

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

### Cite this

*Calphad: Computer Coupling of Phase Diagrams and Thermochemistry*,

*38*, 92-99. https://doi.org/10.1016/j.calphad.2012.04.005

}

*Calphad: Computer Coupling of Phase Diagrams and Thermochemistry*, vol. 38, pp. 92-99. https://doi.org/10.1016/j.calphad.2012.04.005

**First-principles calculations and thermodynamic re-modeling of the Hf-W system.** / Lieser, Alyson C.; Zacherl, Chelsey L.; Saengdeejing, Arkapol; Liu, Zi-kui; Kecskes, Laszlo J.

Research output: Contribution to journal › Article

TY - JOUR

T1 - First-principles calculations and thermodynamic re-modeling of the Hf-W system

AU - Lieser, Alyson C.

AU - Zacherl, Chelsey L.

AU - Saengdeejing, Arkapol

AU - Liu, Zi-kui

AU - Kecskes, Laszlo J.

PY - 2012/9/1

Y1 - 2012/9/1

N2 - 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.

AB - 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.

UR - http://www.scopus.com/inward/record.url?scp=84862509484&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84862509484&partnerID=8YFLogxK

U2 - 10.1016/j.calphad.2012.04.005

DO - 10.1016/j.calphad.2012.04.005

M3 - Article

VL - 38

SP - 92

EP - 99

JO - Calphad: Computer Coupling of Phase Diagrams and Thermochemistry

JF - Calphad: Computer Coupling of Phase Diagrams and Thermochemistry

SN - 0364-5916

ER -