scholarly journals Thermodynamic modeling of the In-Sc and In-Y systems supported by first-principles calculations

2018 ◽  
Vol 54 (2) ◽  
pp. 161-167 ◽  
Author(s):  
Z. Hu ◽  
C. Huang ◽  
J. Tu ◽  
Y. Huang ◽  
A. Dong
Keyword(s):  
Intermetallic Compounds ◽  
Thermodynamic Modeling ◽  
First Principles ◽  
Regular Solution Model ◽  
Calphad Method ◽  
Enthalpies Of Formation ◽  
Thermodynamic Optimization ◽  
First Principles Calculations ◽  
Self Consistent ◽  
Good Agreement

Based on an assessment of the phase equilibria and thermodynamic data in the literature, the thermodynamic modeling of the In?Sc and In?Y systems was carried out by means of the calculation of phase diagram (CALPHAD) method supported by first-principles calculations. The solution phases, i.e., liquid, (In), (?Sc), (?Sc), (?Y) and (?Y), were modeled with the substitutional regular solution model. Ten intermetallic compounds, including InSc3, InSc2, In4Sc5, InSc, In2Sc, In3Sc, InY2, InY, In5Y3, and In3Y were described as stoichiometric phases, while In3Y5 was modeled with a sublattice model with respect to its homogeneity range. The enthalpies of formation of the intermetallic compounds at 0 K were computed using firstprinciple calculations and were used as input for the thermodynamic optimization. A set of self-consistent thermodynamic parameters for both the In?Sc and In?Y systems were obtained and the calculated phase diagrams are in good agreement with the experimental data.

scholarly journals Thermodynamic modeling of the Sc-Zn system coupled with first-principles calculation

2012 ◽  
Vol 48 (1) ◽  
pp. 123-130 ◽  
Author(s):  
C. Tang ◽  
P. Zhou ◽  
D.D. Zhao ◽  
X.M. Yuan ◽  
Y. Tang ◽  
...  
Keyword(s):  
Experimental Data ◽  
Phase Diagram ◽  
Thermodynamic Modeling ◽  
First Principles ◽  
Calculated Phase Diagram ◽  
First Principles Calculation ◽  
Enthalpies Of Formation ◽  
First Principles Calculations ◽  
Self Consistent ◽  
Diagram Approach

The Sc-Zn system has been critically reviewed and assessed by means of CALPHAD (CALculation of PHAse Diagram) approach. By means of first-principles calculation, the enthalpies of formation at 0 K for the ScZn, ScZn2, Sc17Zn58, Sc3Zn17 and ScZn12 have been computed with the desire to assist thermodynamic modeling. A set of self-consistent thermodynamic parameters for the Sc-Zn system is then obtained. The calculated phase diagram and thermodynamic properties agree well with the experimental data and first-principles calculations, respectively.

scholarly journals Thermodynamic modeling of the Na-X (X = Si, Ag, Cu, Cr) systems

2012 ◽  
Vol 48 (2) ◽  
pp. 273-282 ◽  
Author(s):  
D. Hao ◽  
M. Bu ◽  
Y. Wang ◽  
Y. Tang ◽  
Q. Gao ◽  
...  
Keyword(s):  
Low Temperature ◽  
Thermodynamic Modeling ◽  
First Principles ◽  
Binary Systems ◽  
Experimental Information ◽  
Enthalpies Of Formation ◽  
Calphad Approach ◽  
First Principles Calculations ◽  
Self Consistent ◽  
Measured Phase

The Na-X (X = Si, Ag, Cu, Cr) systems have been critically reviewed and modeled by means of the CALPHAD approach. The two compounds, NaSi and Ag2Na, are treated as stoichiometric ones. By means of first-principles calculations, the enthalpies of formation at 0 K for the LT-NaSi (low temperature form of NaSi) and Ag2Na have been computed to be -5210 and -29821.8 Jmol-1, respectively, with the desire to assist thermodynamic modeling. One set of self-consistent thermodynamic parameters is obtained for each of these binary systems. Comparisons between calculated and measured phase diagrams show that most of the experimental information can be satisfactorily accounted for by the present thermodynamic descriptions.

The structural stabilities of the intermetallics and the solid-state phase transformations induced by lattice vibration effects in the Al–Zr system by first-principles calculations

2010 ◽  
Vol 25 (9) ◽  
pp. 1689-1694 ◽  
Author(s):  
Hui Zhang ◽  
Shaoqing Wang
Keyword(s):  
Solid State ◽  
Phase Transformations ◽  
High Temperatures ◽  
First Principles ◽  
Lattice Vibration ◽  
Enthalpies Of Formation ◽  
Phase Transformation Temperature ◽  
First Principles Calculations ◽  
Experimental Phase Diagram ◽  
Good Agreement

We investigated the structural stabilities of the intermetallics and the solid-state phase transformations induced by lattice vibration effects in the Al–Zr system by first-principles calculations. The calculated lattice parameters of all the phases and the phonon dispersion relations for pure Al and Zr are in good agreement with the experimental data. AlZr(oC8), Al4Zr5 (hP18), and Al3Zr5 (tI32) are predicted to be the high-temperature phases. To study the structural stabilities at high temperatures, the thermodynamic properties of the intermetallics are calculated via the linear response approach within the harmonic approximation. Thanks to the calculated enthalpies of formation at high temperatures, Al3Zr5 is predicted to be stabilized above 1163 K with respect to AlZr2 and Al2Zr3, in good agreement with the phase transformation temperature (1273 K) in the experimental phase diagram.

scholarly journals Thermodynamic modeling of the Bi-M (M = Ti, Cr, V) systems

2013 ◽  
Vol 49 (3) ◽  
pp. 307-313 ◽  
Author(s):  
Z. Cao ◽  
J. Xin ◽  
C. Chen ◽  
S. Liu ◽  
B. Hu ◽  
...  
Keyword(s):  
Thermodynamic Modeling ◽  
First Principles ◽  
Binary Systems ◽  
Ideal Gas ◽  
First Principles Calculations ◽  
Calphad Technique ◽  
Gas Phases ◽  
Self Consistent ◽  
The Enthalpy Of Formation ◽  
Measured Phase

The Bi-M (M = Ti, Cr, V) systems have been critically reviewed and modeled by means of the CALPHAD technique. All the intermetallics (BiTi3, BiTi2, Bi9Ti8, Bi3Ti2 and Bi2Ti) were treated as stoichiometric compounds. The enthalpy of formation at 0 K for BiTi2 was computed via first-principles calculations to assist the thermodynamic modeling. The gas phases for the Bi-Cr and Bi-V systems were treated as ideal gas. A set of self-consistent thermodynamic parameters has been finally obtained for each of these binary systems. Comparisons between the calculated and measured phase diagrams as well as first-principles calculations show that most of experimental data can be satisfactorily reproduced by the present thermodynamic descriptions.

scholarly journals Thermodynamic description of the Al-Cu-Yb ternary system supported by first-principles calculations

2016 ◽  
Vol 52 (2) ◽  
pp. 177-183 ◽  
Author(s):  
G. Huang ◽  
L. Liu ◽  
L. Zhang ◽  
Z. Jin
Keyword(s):  
Ternary System ◽  
First Principles ◽  
Thermodynamic Description ◽  
Theoretical Data ◽  
Intermetallic Phases ◽  
Calphad Method ◽  
First Principles Calculations ◽  
Self Consistent ◽  
Ternary Intermetallic Compounds ◽  
Phase Relationships

Phase relationships of the ternary Al-Cu-Yb system have been assessed using a combination of CALPHAD method and first principles calculations. A self-consistent thermodynamic parameter was established based on the experimental and theoretical information. Most of the binary intermetallic phases, except Al3Yb, Al2Yb, Cu2Yb and Cu5Yb, were assumed to be zero solubility in the ternary system. Based on the experimental data, eight ternary intermetallic compounds were taken into consideration in this system. Among them, three were treated as line compounds with large homogeneity ranges for Al and Cu. The others were treated as stoichiometric compounds. The calculated phase diagrams were in agreement with available experimental and theoretical data.

Thermodynamic description of Ge-Mn-Si

2014 ◽  
Vol 1642 ◽  
Author(s):  
Alexandre Berche ◽  
Jean-Claude Tédenac ◽  
Philippe Jund ◽  
Stéphane Gorsse
Keyword(s):  
Solid Solution ◽  
Gibbs Energy ◽  
First Principles ◽  
Thermodynamic Description ◽  
Intermetallic Phases ◽  
Calphad Method ◽  
Enthalpies Of Formation ◽  
Mixing Enthalpy ◽  
First Principles Calculations ◽  
First Time

ABSTRACTLiterature data of the Mn-Si system is analyzed and discordances are pointed out. First principles calculations are performed to clarify the enthalpies of formation of the intermetallic phases. Especially the enthalpies of formation of the various possible structures of the MnSix are discussed. On the basis of these new data, a thermodynamic description of the Gibbs energy of the phases is performed using the Calphad method. The system Ge-Mn is also assessed using the Calphad method for the first time.The mixing enthalpy in the D88 solid solution is calculated between Mn5Ge3 and Mn5Si3 by DFT calculations.Finally a thermodynamic description of the ternary system is suggested. Especially the solubility of germanium in MnSix is modeled.

scholarly journals Thermodynamic assessment of the Pb-Sr system

2017 ◽  
Vol 53 (3) ◽  
pp. 179-187 ◽  
Author(s):  
H. Zhang ◽  
C. Zhang ◽  
W.W. Wang ◽  
Y. Du ◽  
P. Zhou ◽  
...  
Keyword(s):  
First Principles ◽  
Thermodynamic Assessment ◽  
Thermodynamic Description ◽  
Experimental Information ◽  
Enthalpies Of Formation ◽  
First Principles Calculations ◽  
Exponential Polynomials ◽  
Self Consistent ◽  
Five Phases ◽  
Measured Phase Diagram

The Pb-Sr system has been critically reviewed and modeled by means of the CALPHAD (CALculation of PHAse Diagrams) approach. It contains seven stoichiometric compounds, i.e. SrPb3, Sr3Pb5, Sr2Pb3, SrPb, Sr5Pb4, Sr5Pb3 and Sr2Pb, in which the SrPb3 and Sr2Pb phases melt congruently, and the other five phases form via peritectic reactions. The enthalpies of formation for the intermetallic compounds at 0 K are provided by first-principles calculations. The liquid, fcc and bcc phases are modeled as substitutional solution phases. Both Redlich-Kister and exponential polynomials are used to describe the excess Gibbs energy of the liquid. Two sets of self-consistent thermodynamic parameters are obtained by considering reliable experimental data and the computed enthalpies of formation. Comprehensive comparisons between the calculated and measured phase diagram and thermodynamic data show that the experimental information is satisfactorily accounted for by the present thermodynamic description.

Stability and Structures of Constitutional Defects in Nonstoichiometric Intermetallic Compounds by First-Principles Calculations

2005 ◽  
Vol 475-479 ◽  
pp. 3111-3114
Author(s):  
Masataka Mizuno ◽  
Hideki Araki ◽  
Yasuharu Shirai
Keyword(s):  
Intermetallic Compounds ◽  
First Principles ◽  
Electronic Structures ◽  
Stoichiometric Composition ◽  
Electronic Structure Calculations ◽  
First Principles Calculations ◽  
Compositional Dependence ◽  
Wide Range ◽  
Formation Energies ◽  
Structure Calculations

Some of intermetallic compounds exist in a wide range of concentration around the stoichiometric composition. First-principles electronic structure calculations have been performed for constitutional defects in non-stoichiometric CoAl and CoTi in order to investigate their stabilities and structural relaxations induced by constitutional defects. For the evaluation of stabilities of constitutional defects, the compositional dependence curves both of formation energies and of lattice parameters are obtained by the calculations employing supercells in various sizes. The lattice relaxations around constitutional defects are discussed by analyzing the change in electronic structures induced by constitutional defects.

First-principles calculations and thermodynamic modeling of the Sn−Sr and Mg−Sn−Sr systems

Calphad ◽  
2014 ◽  
Vol 46 ◽  
pp. 237-248 ◽  
Author(s):  
Bi-Cheng Zhou ◽  
Shun-Li Shang ◽  
Zi-Kui Liu
Keyword(s):  
Thermodynamic Modeling ◽  
First Principles ◽  
First Principles Calculations
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