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.

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U2 - 10.1016/j.calphad.2012.04.005

DO - 10.1016/j.calphad.2012.04.005

M3 - Article

AN - SCOPUS:84862509484

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 -