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Sundman, Bo
Publications (3 of 3) Show all publications
Zeng, Y., Du, Y., Li, H., Zhou, P., Liu, S., Cheng, K., . . . Dreval, L. (2019). Thermodynamic description and solidified microstructure of the Co-Ge system. Journal of Alloys and Compounds, 793, 480-491
Open this publication in new window or tab >>Thermodynamic description and solidified microstructure of the Co-Ge system
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2019 (English)In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 793, p. 480-491Article in journal (Refereed) Published
Abstract [en]

The Co-Ge binary system was reassessed by CALPHAD method in view of new phase diagram data and drawbacks of the previous modeling. A three-sublattice model (Co,Va)(1)(Co)(1)(Ge)(1 )was used to describe the B8(2)-type beta Co5Ge3-phase based on its crystal structure. In order to describe the transformation between ordered L1(2)-type phase (Co3Ge) and the disordered fcc_Al phase (alpha Co), one single Gibbs energy function was used for both ordered and disordered phases. In almost all the previous thermodynamic calculations, the ordered phase with a negligible homogeneity range, such as Co3Ge, is treated as a stoichiometric compound. Such a treatment is not physically sound. For (alpha Co) and (alpha Co), the magnetic contribution to Gibbs energy is taken into account. Both substitutional solution model and associated model were applied to describe the liquid phase, and thus two sets of self-consistent thermodynamic parameters for this system were obtained. It was found that the associated model can account for the experimental data more satisfactorily than the substitutional solution model, especially for the partial enthalpy of mixing data for the liquid phase. Five representative as-cast Co-Ge alloys were prepared to compare the solidified microstructure with that predicted according to thermodynamic calculations. According to the calculated Scheil solidification curves of two key alloys, the solidified microstructure for the alloys was analyzed. Also, the calculated amounts of the solidified phases in five as-cast alloys are compared with the experimental data resulting from automatic image analysis of the BSE images, showing a good agreement between the calculation and experiment, in particular for the case in which the associated model is used to describe the properties of the liquid phase. It is demonstrated that the combined use of the thermodynamic calculation and decisive experiment is an efficient strategy to obtain the desired microstructure.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE SA, 2019
Keywords
Disorder/order transition, Thermodynamics, Phase diagram, Solidified microstructure
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-252585 (URN)10.1016/j.jallcom.2018.12.205 (DOI)000467696000053 ()2-s2.0-85064697710 (Scopus ID)
Note

QC 20190611

Available from: 2019-06-11 Created: 2019-06-11 Last updated: 2019-06-11Bibliographically approved
Corcoran, E. C., Fleche, J.-L. -., Dupin, N., Sundman, B. & Gueneau, C. (2018). Thermodynamic investigations of the uranium-molybdenum-oxygen system by a coupling of density functional theory and CALPHAD methodologies. Calphad, 63, 196-211
Open this publication in new window or tab >>Thermodynamic investigations of the uranium-molybdenum-oxygen system by a coupling of density functional theory and CALPHAD methodologies
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2018 (English)In: Calphad, ISSN 0364-5916, E-ISSN 1873-2984, Vol. 63, p. 196-211Article in journal (Refereed) Published
Abstract [en]

This paper examines the development of a consistent thermodynamic model for the uranium (U) - molybdenum (Mo) - oxygen (0) system for incorporation into the Thermodynamics of Advanced Fuels - International Database (TAF-ID). Phase diagram data and thermodynamic properties from the literature are reviewed. Density functional theory ab initio calculations at 0 K are combined with a quasi -harmonic statistical thermodynamic model to calculate thermodynamic functions (e.g., integral Delta H-298.15K(0), S-298.15K(0), and C-p(0) (T))of the relevant ternary compounds when little or no thermodynamic literature data are available. A CALPHAD method is employed to derive a model describing the Gibbs energy functions for all the relevant ternary compounds, the liquid phase, and the gas phase of the U-Mo-O system. A consistent thermodynamic model is obtained for the Mo-U-0 system with a special emphasis placed on the oxygen rich portion of the ternary (ie., MoO2-UO2-O). Finally, supporting binary and pseudo binary diagrams (e.g., Mo-O, UO2-MoO3 and UO3-MoO3) are computed and compared to literature data.

Place, publisher, year, edition, pages
PERGAMON-ELSEVIER SCIENCE LTD, 2018
Keywords
Mo-U-O, Thermodynamic description, DFT, Ab initio, Quasi-harmonic models, CALPHAD
National Category
Other Engineering and Technologies
Identifiers
urn:nbn:se:kth:diva-241012 (URN)10.1016/j.calphad.2018.10.002 (DOI)000453496700022 ()2-s2.0-85055735073 (Scopus ID)
Note

QC 20190709

Available from: 2019-01-09 Created: 2019-01-09 Last updated: 2019-08-20Bibliographically approved
Zinkevich, M., Aldinger, F. & Sundman, B. (2007). The Ringberg workshop 2005 on thermodynamic modeling and first-principles calculations. Calphad, 31(1), 2-3
Open this publication in new window or tab >>The Ringberg workshop 2005 on thermodynamic modeling and first-principles calculations
2007 (English)In: Calphad, ISSN 0364-5916, E-ISSN 1873-2984, Vol. 31, no 1, p. 2-3Article in journal, Editorial material (Other academic) Published
Place, publisher, year, edition, pages
Max Planck Inst Met Res, Stuttgart, Germany. Royal Inst Technol, Stockholm, Sweden.: PERGAMON-ELSEVIER SCIENCE LTD, 2007
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-242958 (URN)10.1016/j.calphad.2006.02.003 (DOI)000244242100001 ()2-s2.0-33846327239 (Scopus ID)
Note

QC 20190206

Available from: 2019-02-06 Created: 2019-02-06 Last updated: 2019-02-06Bibliographically approved
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