First-principles calculations of energetics of sigma phase formation and thermodynamic modelling in the Cr–Fe–W system

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2007-07, Vol.462 (1), p.153-158
• Main Authors: CHVATALOVA, K, VREST'AL, J, HOUSEROVA, J, SOB, M
• Format: Article
• Language: English
• Subjects: CALPHAD approach; Chromium; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; First-principles calculations; Iron; Materials science; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Phase diagrams of metals and alloys; Physics; Sigma phase; Thermodynamic modelling; Tungsten
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2006.02.474

Ab initio total energies of the alloy sigma phase in Cr–W and Fe–W systems were calculated by means of the linear muffin-tin orbital method in the atomic sphere approximation. Total energies of the pure constituents in the sigma phase and standard element reference (SER) states were evaluated using the full-potential linear augmented plane wave method. The combination of these results was used for the prediction of the energy of formation of the sigma phase with respect to both sigma phase of pure constituents and SER states at equilibrium structure parameters. We have also provided a novel physical approach to the thermodynamic modelling of the sigma phase and a reliable construction of the phase diagram of the Cr–Fe–W system, using ab initio calculated total energy differences in the calculation of phase diagram (CALPHAD) approach.