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  Subjects -> COMPUTER SCIENCE (Total: 2132 journals)
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COMPUTER SCIENCE (1238 journals)                  1 2 3 4 5 6 7 | Last

Showing 1 - 200 of 872 Journals sorted alphabetically
3D Printing and Additive Manufacturing     Full-text available via subscription   (Followers: 25)
Abakós     Open Access   (Followers: 4)
ACM Computing Surveys     Hybrid Journal   (Followers: 31)
ACM Journal on Computing and Cultural Heritage     Hybrid Journal   (Followers: 9)
ACM Journal on Emerging Technologies in Computing Systems     Hybrid Journal   (Followers: 17)
ACM Transactions on Accessible Computing (TACCESS)     Hybrid Journal   (Followers: 3)
ACM Transactions on Algorithms (TALG)     Hybrid Journal   (Followers: 15)
ACM Transactions on Applied Perception (TAP)     Hybrid Journal   (Followers: 5)
ACM Transactions on Architecture and Code Optimization (TACO)     Hybrid Journal   (Followers: 9)
ACM Transactions on Autonomous and Adaptive Systems (TAAS)     Hybrid Journal   (Followers: 9)
ACM Transactions on Computation Theory (TOCT)     Hybrid Journal   (Followers: 12)
ACM Transactions on Computational Logic (TOCL)     Hybrid Journal   (Followers: 3)
ACM Transactions on Computer Systems (TOCS)     Hybrid Journal   (Followers: 18)
ACM Transactions on Computer-Human Interaction     Hybrid Journal   (Followers: 16)
ACM Transactions on Computing Education (TOCE)     Hybrid Journal   (Followers: 8)
ACM Transactions on Design Automation of Electronic Systems (TODAES)     Hybrid Journal   (Followers: 6)
ACM Transactions on Economics and Computation     Hybrid Journal   (Followers: 1)
ACM Transactions on Embedded Computing Systems (TECS)     Hybrid Journal   (Followers: 3)
ACM Transactions on Information Systems (TOIS)     Hybrid Journal   (Followers: 20)
ACM Transactions on Intelligent Systems and Technology (TIST)     Hybrid Journal   (Followers: 8)
ACM Transactions on Interactive Intelligent Systems (TiiS)     Hybrid Journal   (Followers: 5)
ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP)     Hybrid Journal   (Followers: 9)
ACM Transactions on Reconfigurable Technology and Systems (TRETS)     Hybrid Journal   (Followers: 6)
ACM Transactions on Sensor Networks (TOSN)     Hybrid Journal   (Followers: 8)
ACM Transactions on Speech and Language Processing (TSLP)     Hybrid Journal   (Followers: 9)
ACM Transactions on Storage     Hybrid Journal  
ACS Applied Materials & Interfaces     Hybrid Journal   (Followers: 35)
Acta Automatica Sinica     Full-text available via subscription   (Followers: 2)
Acta Informatica Malaysia     Open Access  
Acta Universitatis Cibiniensis. Technical Series     Open Access  
Ad Hoc Networks     Hybrid Journal   (Followers: 11)
Adaptive Behavior     Hybrid Journal   (Followers: 10)
Advanced Engineering Materials     Hybrid Journal   (Followers: 29)
Advanced Science Letters     Full-text available via subscription   (Followers: 11)
Advances in Adaptive Data Analysis     Hybrid Journal   (Followers: 8)
Advances in Artificial Intelligence     Open Access   (Followers: 15)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 6)
Advances in Catalysis     Full-text available via subscription   (Followers: 5)
Advances in Computational Mathematics     Hybrid Journal   (Followers: 19)
Advances in Computer Engineering     Open Access   (Followers: 4)
Advances in Computer Science : an International Journal     Open Access   (Followers: 15)
Advances in Computing     Open Access   (Followers: 2)
Advances in Data Analysis and Classification     Hybrid Journal   (Followers: 59)
Advances in Engineering Software     Hybrid Journal   (Followers: 29)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 16)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 23)
Advances in Human-Computer Interaction     Open Access   (Followers: 21)
Advances in Materials Science     Open Access   (Followers: 15)
Advances in Operations Research     Open Access   (Followers: 12)
Advances in Parallel Computing     Full-text available via subscription   (Followers: 7)
Advances in Porous Media     Full-text available via subscription   (Followers: 5)
Advances in Remote Sensing     Open Access   (Followers: 52)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Advances in Technology Innovation     Open Access   (Followers: 6)
AEU - International Journal of Electronics and Communications     Hybrid Journal   (Followers: 8)
African Journal of Information and Communication     Open Access   (Followers: 9)
African Journal of Mathematics and Computer Science Research     Open Access   (Followers: 4)
AI EDAM     Hybrid Journal   (Followers: 1)
Air, Soil & Water Research     Open Access   (Followers: 14)
AIS Transactions on Human-Computer Interaction     Open Access   (Followers: 7)
Algebras and Representation Theory     Hybrid Journal   (Followers: 1)
Algorithms     Open Access   (Followers: 11)
American Journal of Computational and Applied Mathematics     Open Access   (Followers: 5)
American Journal of Computational Mathematics     Open Access   (Followers: 4)
American Journal of Information Systems     Open Access   (Followers: 6)
American Journal of Sensor Technology     Open Access   (Followers: 4)
Anais da Academia Brasileira de Ciências     Open Access   (Followers: 2)
Analog Integrated Circuits and Signal Processing     Hybrid Journal   (Followers: 7)
Analysis in Theory and Applications     Hybrid Journal   (Followers: 1)
Animation Practice, Process & Production     Hybrid Journal   (Followers: 5)
Annals of Combinatorics     Hybrid Journal   (Followers: 4)
Annals of Data Science     Hybrid Journal   (Followers: 12)
Annals of Mathematics and Artificial Intelligence     Hybrid Journal   (Followers: 12)
Annals of Pure and Applied Logic     Open Access   (Followers: 4)
Annals of Software Engineering     Hybrid Journal   (Followers: 13)
Annals of West University of Timisoara - Mathematics and Computer Science     Open Access  
Annual Reviews in Control     Hybrid Journal   (Followers: 8)
Anuario Americanista Europeo     Open Access  
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2)
Applied and Computational Harmonic Analysis     Full-text available via subscription   (Followers: 1)
Applied Artificial Intelligence: An International Journal     Hybrid Journal   (Followers: 12)
Applied Categorical Structures     Hybrid Journal   (Followers: 5)
Applied Clinical Informatics     Hybrid Journal   (Followers: 3)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 14)
Applied Computer Systems     Open Access   (Followers: 2)
Applied Informatics     Open Access  
Applied Mathematics and Computation     Hybrid Journal   (Followers: 33)
Applied Medical Informatics     Open Access   (Followers: 12)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Soft Computing     Hybrid Journal   (Followers: 17)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 7)
Applied System Innovation     Open Access  
Architectural Theory Review     Hybrid Journal   (Followers: 3)
Archive of Applied Mechanics     Hybrid Journal   (Followers: 6)
Archive of Numerical Software     Open Access  
Archives and Museum Informatics     Hybrid Journal   (Followers: 153)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 6)
arq: Architectural Research Quarterly     Hybrid Journal   (Followers: 8)
Artifact     Open Access   (Followers: 2)
Artificial Life     Hybrid Journal   (Followers: 7)
Asia Pacific Journal on Computational Engineering     Open Access  
Asia-Pacific Journal of Information Technology and Multimedia     Open Access   (Followers: 1)
Asian Journal of Control     Hybrid Journal  
Assembly Automation     Hybrid Journal   (Followers: 2)
at - Automatisierungstechnik     Hybrid Journal   (Followers: 1)
Australian Educational Computing     Open Access   (Followers: 1)
Automatic Control and Computer Sciences     Hybrid Journal   (Followers: 6)
Automatic Documentation and Mathematical Linguistics     Hybrid Journal   (Followers: 5)
Automatica     Hybrid Journal   (Followers: 13)
Automation in Construction     Hybrid Journal   (Followers: 7)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 8)
Balkan Journal of Electrical and Computer Engineering     Open Access  
Basin Research     Hybrid Journal   (Followers: 5)
Behaviour & Information Technology     Hybrid Journal   (Followers: 51)
Big Data and Cognitive Computing     Open Access   (Followers: 4)
Biodiversity Information Science and Standards     Open Access  
Bioinformatics     Hybrid Journal   (Followers: 333)
Biomedical Engineering     Hybrid Journal   (Followers: 16)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 13)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 19)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 35)
Briefings in Bioinformatics     Hybrid Journal   (Followers: 51)
British Journal of Educational Technology     Hybrid Journal   (Followers: 163)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 12)
c't Magazin fuer Computertechnik     Full-text available via subscription   (Followers: 1)
CALCOLO     Hybrid Journal  
Calphad     Hybrid Journal   (Followers: 2)
Canadian Journal of Electrical and Computer Engineering     Full-text available via subscription   (Followers: 15)
Capturing Intelligence     Full-text available via subscription  
Catalysis in Industry     Hybrid Journal   (Followers: 1)
CEAS Space Journal     Hybrid Journal   (Followers: 2)
Cell Communication and Signaling     Open Access   (Followers: 2)
Central European Journal of Computer Science     Hybrid Journal   (Followers: 5)
CERN IdeaSquare Journal of Experimental Innovation     Open Access   (Followers: 3)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 15)
ChemSusChem     Hybrid Journal   (Followers: 7)
China Communications     Full-text available via subscription   (Followers: 8)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
CIN Computers Informatics Nursing     Hybrid Journal   (Followers: 11)
Circuits and Systems     Open Access   (Followers: 15)
Clean Air Journal     Full-text available via subscription   (Followers: 1)
CLEI Electronic Journal     Open Access  
Clin-Alert     Hybrid Journal   (Followers: 1)
Clinical eHealth     Open Access  
Cluster Computing     Hybrid Journal   (Followers: 2)
Cognitive Computation     Hybrid Journal   (Followers: 3)
COMBINATORICA     Hybrid Journal  
Combinatorics, Probability and Computing     Hybrid Journal   (Followers: 4)
Combustion Theory and Modelling     Hybrid Journal   (Followers: 14)
Communication Methods and Measures     Hybrid Journal   (Followers: 13)
Communication Theory     Hybrid Journal   (Followers: 24)
Communications Engineer     Hybrid Journal   (Followers: 1)
Communications in Algebra     Hybrid Journal   (Followers: 3)
Communications in Computational Physics     Full-text available via subscription   (Followers: 2)
Communications in Information Science and Management Engineering     Open Access   (Followers: 4)
Communications in Partial Differential Equations     Hybrid Journal   (Followers: 4)
Communications of the ACM     Full-text available via subscription   (Followers: 51)
Communications of the Association for Information Systems     Open Access   (Followers: 16)
COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering     Hybrid Journal   (Followers: 3)
Complex & Intelligent Systems     Open Access   (Followers: 1)
Complex Adaptive Systems Modeling     Open Access  
Complex Analysis and Operator Theory     Hybrid Journal   (Followers: 2)
Complexity     Hybrid Journal   (Followers: 6)
Complexus     Full-text available via subscription  
Composite Materials Series     Full-text available via subscription   (Followers: 8)
Computación y Sistemas     Open Access  
Computation     Open Access   (Followers: 1)
Computational and Applied Mathematics     Hybrid Journal   (Followers: 3)
Computational and Mathematical Biophysics     Open Access   (Followers: 1)
Computational and Mathematical Methods in Medicine     Open Access   (Followers: 2)
Computational and Mathematical Organization Theory     Hybrid Journal   (Followers: 2)
Computational and Structural Biotechnology Journal     Open Access   (Followers: 1)
Computational and Theoretical Chemistry     Hybrid Journal   (Followers: 9)
Computational Astrophysics and Cosmology     Open Access   (Followers: 1)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 13)
Computational Chemistry     Open Access   (Followers: 2)
Computational Cognitive Science     Open Access   (Followers: 2)
Computational Complexity     Hybrid Journal   (Followers: 4)
Computational Condensed Matter     Open Access   (Followers: 1)
Computational Ecology and Software     Open Access   (Followers: 10)
Computational Economics     Hybrid Journal   (Followers: 10)
Computational Geosciences     Hybrid Journal   (Followers: 17)
Computational Linguistics     Open Access   (Followers: 23)
Computational Management Science     Hybrid Journal  
Computational Mathematics and Modeling     Hybrid Journal   (Followers: 8)
Computational Mechanics     Hybrid Journal   (Followers: 5)
Computational Methods and Function Theory     Hybrid Journal  
Computational Molecular Bioscience     Open Access   (Followers: 2)
Computational Optimization and Applications     Hybrid Journal   (Followers: 8)
Computational Particle Mechanics     Hybrid Journal   (Followers: 1)
Computational Research     Open Access   (Followers: 1)
Computational Science and Discovery     Full-text available via subscription   (Followers: 2)
Computational Science and Techniques     Open Access  
Computational Statistics     Hybrid Journal   (Followers: 14)
Computational Statistics & Data Analysis     Hybrid Journal   (Followers: 35)
Computer     Full-text available via subscription   (Followers: 105)
Computer Aided Surgery     Open Access   (Followers: 6)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 8)
Computer Communications     Hybrid Journal   (Followers: 16)

        1 2 3 4 5 6 7 | Last

Journal Cover
Calphad
Journal Prestige (SJR): 0.832
Citation Impact (citeScore): 2
Number of Followers: 2  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0364-5916
Published by Elsevier Homepage  [3160 journals]
  • The influence of lattice vibrations and electronic free energy on phase
           stability of titanium silicides and Si solubility in hcp titanium: A DFT
           study
    • Abstract: Publication date: June 2019Source: Calphad, Volume 65Author(s): A.I. Kartamyshev, D.O. Poletaev, A.G. Lipnitskii In this paper, we evaluated the influence of vibrational and electronic free energy on the thermodynamic phase stability of the Ti5Si3, Ti3Si, Ti6Si3, and other silicides in the binary Ti-Si system and the solubility of Si in α-Ti within the density functional theory and harmonic approximation. We showed, that vibrational and electronic free energy thermodynamically stabilize the Ti3Si silicide and destabilize the Ti6Si3 silicide with respect to the Ti5Si3 and α-Ti. According to our calculations, the transition from equilibrium of Si solid solution with the Ti5Si3 silicide to the equilibrium of Si solid solution with the Ti3Si silicide should be at ∼ 900 K. The account of both the vibrational and electronic free energy increase the calculated solubility limit of Si in α-Ti and make it closer to the experimental one.
       
  • Thermodynamic description of the Gd2O3-Y2O3-HfO2 and La2O3-Y2O3-HfO2
           systems at high temperatures
    • Abstract: Publication date: June 2019Source: Calphad, Volume 65Author(s): A.L. Shilov, V.L. Stolyarova, V.A. Vorozhtcov, S.I. Lopatin Thermodynamic properties of the Gd2O3-Y2O3-HfO2 and La2O3-Y2O3-HfO2 systems were obtained by Knudsen effusion mass spectrometric method at the temperatures 2500 K and 2337 K, respectively. Description of the thermodynamic properties of these systems was obtained using the Barker theory. It was illustrated that negative deviations from the ideality in these systems were related to the formation of the Me-O-Y and Y-O-Hf bonds in the solid solutions. Accuracy of the optimization of the thermodynamic data in the Gd2O3-Y2O3-HfO2 system using the Barker theory was checked in comparison with the traditional Redlich-Kister approximation approach.
       
  • Dimer neutral ion pairs and associative ions in saturated vapor of
           1-ethyl-3-methylimidazolium trifluoromethanesulfonate ionic liquid
    • Abstract: Publication date: June 2019Source: Calphad, Volume 65Author(s): A.M. Dunaev, V.B. Motalov, D.N. Govorov, L.S. Kudin In the temperature range of 388–506 K in saturated vapor over 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMImTfO) ionic liquid along with the monomer neutral ionic pairs (NIP) C+A–, where C+ is EMIm+ (cation) and A– is TfO– (anion), the dimers (C+A–)2 were registered with a fraction of 0.5% for the first time. The corresponding associative ions C2A+ and C3A2+ formed as a result of attachment of the cation C+ to the monomer and dimer NIPs were also found. The evaporation enthalpies ΔvH°(298.15 K) = 128 ± 5 kJ mol–1 (monomer) and ΔvH°(298.15 K) = 161 ± 9 kJ mol–1 (dimer) were determined. The enthalpy of formation of the monomer and dimer NIP of EMImTfO at 298.15 K in the state of ideal gas were derived from the evaporation enthalpies: –1033 ± 50 kJ mol–1 and –2160 ± 50 kJ mol–1, respectively. The desorption enthalpies ΔdesH°(T) of the C+, C2A+, and C3A2+ cations were found to be 164 ± 5 kJ mol–1 (435 K), 159 ± 7 kJ mol–1 (435 K), and 152 ± 21 kJ mol–1(457 K), respectively. The equilibrium constants of the heterophase ion-molecular reactions were measured and the formation enthalpies of associative ions were calculated: ΔfH°(C2A+, 298.15 K) = –493 ± 50 kJ mol–1 and ΔfH°(C3A2+, 298.15 K) = –1631 ± 50 kJ mol–1.Graphical abstractfx1
       
  • Thermal analysis and Knudsen effusion mass spectrometry combined in a
           specially-adapted commercial skimmer coupled instrument (Netzsch)
    • Abstract: Publication date: June 2019Source: Calphad, Volume 65Author(s): Pavel Brož, František Zelenka, Jiří Sopoušek, Martina Hejduková, Tereza Kuběnová, Ondřej Zobač The paper is aimed at informing on Netzsch STA 409 CD/3/403/5/G apparatus, a specially-adapted type of the commercial STA 409 CD - QMS 403/5 Skimmer Coupling Instrument combining methods of thermal analysis with Knudsen effusion mass spectrometry. Construction parameters as well as advantages and disadvantages of the instrument are presented. The instrument can be used for a broad spectrum of studies in materials field from which some of them, including e.g. thermodynamic and phase transformations studies, study of surface and catalytic processes, investigation of materials on multiscale level, are demonstrated. The new multifunction design as well as the instrument capabilities are discussed with respect to already published information.Graphical abstractfx1
       
  • Identification of volatile metal hydroxides with free jet expansion
           sampling mass spectrometry
    • Abstract: Publication date: June 2019Source: Calphad, Volume 65Author(s): Dwight L. Myers, Nathan S. Jacobson Free jet expansion sampling mass spectrometry is a valuable tool for identifying high temperature vapor species formed in a 1 bar process. The system at NASA Glenn consists of four differentially pumped vacuum chambers. A Pt/20Rh entrance nozzle from the 1 bar process to a rapidly pumped chamber creates the free jet expansion. This is followed by a skimmer and thus an intense supersonic molecular beam is formed and directed to a quadrupole mass spectrometer. An unobstructed path to the mass spectrometer allows direct identification of condensable and non-condensable vapor species formed at 1 bar while preserving their chemical and dynamic integrity.This system has been very valuable for identification of metal hydroxides and oxyhydroxides which would not have been seen in a low pressure system. We discuss studies of Si(OH)4, Al(OH)3, TaO(OH)3, B(OH)3, and CrO2(OH)2 vapors.
       
  • Vaporization behavior of Na2CO3 and
           K2CO3
    • Abstract: Publication date: June 2019Source: Calphad, Volume 65Author(s): D. Sergeev, E. Yazhenskikh, D. Kobertz, M. Müller Sodium and potassium carbonates are important components of high temperature materials. Therefore, information on gas phase is important for modelling of long term processes, where the stability of carbonates should be taken into account. In this study the vaporization behavior of Na2CO3 and K2CO3 has been studied with Knudsen Effusion Mass Spectrometry in the temperature range from 600 to 880 °C. It was established, that vaporization of sodium and potassium carbonates is close to congruent conditions at temperatures below 750 °C with the main species M, CO2 and O2 in the gas phase. The vapor pressures of these species are in a good agreement with the calculated values within an error of ± 30%, which are based on the available thermodynamic information including formation enthalpies of M2CO3(s) and M(g), CO2(g) and O2(g) and corresponding thermodynamic functions. At high temperatures above 750 °C incongruent vaporization was observed due to a disproportional increase of the vapor pressure of CO2. On this stage also Na2O+, K2O+ and K2CO3+ ions were registered in the mass spectra. Based on the analysis of fragmentation processes of M2CO3 molecules, the sublimation enthalpy ∆subH°298(K2CO3) is obtained to be 360 kJ/mol.
       
  • Spurious molecular beams in Knudsen effusion mass spectrometry
    • Abstract: Publication date: June 2019Source: Calphad, Volume 65Author(s): Christian Chatillon, Ioana Nuta
       
  • Study of thermal stability of CoSb3 skutterudite by Knudsen
           effusion mass spectrometry
    • Abstract: Publication date: June 2019Source: Calphad, Volume 65Author(s): Pavel Brož, František Zelenka, Zdeněk Kohoutek, Jan Vřešťál, Vít Vykoukal, Jiří Buršík, Adéla Zemanová, Gerda Rogl, Peter Rogl Thermoelectric materials play an important role in the field of renewable energy for their ability of thermal energy conversion into electricity (thermoelectric generator) and reversibly electric energy conversion into thermal energy (thermoelectric heat pump or Peltier cooling). Doped CoSb3 based skutterudites represent one of the very promising categories for the development of highly efficient thermoelectric materials for the conversion of waste heat to electricity. The thermoelectric efficiency, however, is closely related to thermal and phase stability as the current materials contain volatile elements (Sb, Sr, Yb, etc.), which can evaporate at operation conditions and thus cause structure changes and damage the thermoelectric properties. For a better understanding of the thermal behaviour of complex multicomponent CoSb3 based skutterudite systems, a study of the thermal stability of primary CoSb3 skutterudite is necessary.In this work, the thermal and phase stability of primary CoSb3 skutterudite prepared by ball milling and hot pressing was investigated using thermal analysis and Knudsen effusion mass spectrometry performed on a Netzsch STA 409 CD/3/403/5/G apparatus, a specially-adapted type of the commercial STA 409 CD - QMS 403/5 Skimmer Coupling Instrument. Results, including data on phase transformations and those from vapour pressure measurements of antimony, supported by measurements of diffusion profiles and microstructure observations are summarized and used for evaluation of the long term thermal stability of the material.Graphical abstractfx1
       
  • A general model to calculate coherent solid/solid and immiscible
           liquid/liquid interfacial energies
    • Abstract: Publication date: June 2019Source: Calphad, Volume 65Author(s): Yuling Liu, Shuhong Liu, Yong Du, Yingbiao Peng, Cong Zhang, Sheng Yao Interfacial energy plays a significant role in the microstructure evolution of materials. A general model for predicting both coherent solid/solid and immiscible liquid/liquid interfacial energies is derived from a thermodynamic point of view. In this model, the interfacial energy can be calculated only using the data about molar area and Gibbs energies of two bulk phases and interface phase. The present model is applied to the coherent solid/solid interfacial energies in the Al–Ni, Ni–Ge, Ni–Ga, Ni–Si, Ni–Ti, Au–Ni and Ni–Cr–Al systems. The model-predicted interfacial energies show a reasonable agreement with the literature data. The presently developed model can calculate the interfacial energies between the disordered γ (fcc_A1) and ordered γ’ (fcc_L12) phases, where the Gibbs energies of both γ and γ’ phases are given by the same expression. The previous model in the literature cannot capture some disordered/ordered interfacial energies, like the Al–Ni system. The present model can also be used to calculate the immiscible liquid/liquid interfacial energies in the Al–Pb, Al–In and Al–Bi systems, showing a good agreement with the literature data. These applications validate the reliability of present model in the calculation of coherent solid/solid and immiscible liquid/liquid interfacial energies in the binary and multi-component systems.
       
  • Experimental investigation of phase equilibria in the Tb-Si-Cr system
    • Abstract: Publication date: June 2019Source: Calphad, Volume 65Author(s): X.M. Huang, T. Hu, S.H. Liu, G.M. Cai, Y.H. He, Z.P. Jin Tb-Si intermetallics have been recognized as interesting magnetic and electrical materials. The addition of Cr can modify the property and broaden the application of Tb-Si intermetallic compounds. Understanding phase relations, phase stability and microstructural changes of relative systems are essential for tuning and improving performance of this type of materials. In this work, phase relationships in the Tb-Si-Cr ternary system have been studied based on phase and microstructure identification of key equilibrated alloys. Isothermal sections of this system at 1273 K and 1073 K were experimentally constructed by means of electron probe microanalysis, X-ray diffraction, and differential thermal analysis. As one of results, the ternary compound TbSi2Cr2 was confirmed to exist at both 1273 K and 1073 K. In addition, remarkable solubilities of the third element were detected in some binary compounds. The solubility of Cr in Tb2Si3-δ and TbSi at 1273 K are about 4.0 and 9.1 at%, respectively. The solubility of Cr in Tb5Si3 increases from 3.0 at% at 1273 K to 6.2 at% at 1073 K. Besides, the compound Tb2Si3-δ were determined to be stable ranging from 1098 ± 25 K to 1513 ± 10 K, based on the analysis of microstructure. Moreover, the annealing temperature dependence of micro-hardness for Tb2Si3-δ intermetallic phase was investigated by nano-indentation.
       
  • Investigation of diffusion behavior and mechanical properties of Mg-Zn
           system
    • Abstract: Publication date: June 2019Source: Calphad, Volume 65Author(s): Yifang Ouyang, Ke Liu, Chenyu Peng, Hongmei Chen, Xiaoma Tao, Yong Du The growth kinetics, diffusion kinetics and mechanical properties of intermetallics in Mg-Zn binary systems have been investigated in this work. Four intermetallic compounds (IMCs) Mg2Zn11, MgZn2, Mg21Zn25, and Mg4Zn7 have been observed in the Mg-Zn diffusion zone at the temperature range of 523–593 K. The square of thickness for IMCs diffusion layer increases linearly with time, which is consistent with the parabolic growth law, and also indicates that the growth of IMCs is controlled by diffusion. Growth constants and growth activation energies of Mg-Zn IMCs have been evaluated. Average effective interdiffusion coefficient of each phase has been calculated by the Wagner's method based on the concentration distribution obtained by EPMA. The diffusion activation energy has been estimated and compared with the available results. Finally, displacement-unloading curve measured by nanoindentation was used to estimate the hardness and Young's modulus to characterize the mechanical and creep properties of Mg2Zn11, MgZn2, Mg21Zn25 and Mg4Zn7. The present results should be beneficial to the design and performance of Mg-based alloys.
       
  • Experimental thermodynamic investigation of the liquid Cu-Li-Sn system by
           Knudsen Effusion Mass Spectrometry
    • Abstract: Publication date: June 2019Source: Calphad, Volume 65Author(s): L. Bencze, D. Henriques, V. Motalov, Á. Kolay Kovács, T. Markus The thermodynamic activity of lithium was measured by Knudsen Effusion Mass Spectrometry (KEMS) within the Cu-Li-Sn system in the liquid region. For this purpose, eleven samples were studied between 773 and 1078 K in the Sn-rich part of the Cu-Li-Sn phase diagram. Mixing enthalpies, entropies and Gibbs energies were derived directly from the measured thermodynamic activity. The measured thermodynamic activities of Li were fitted to the Redlich-Kister-Muggianu (RKM) sub-regular solution model, by taking ternary interactions into account, using a mathematical regression procedure. Thereby, the partial and integral excess thermodynamic properties, the activities of Li, Cu and Sn and the ternary interaction L-parameters, as a function of temperature, were obtained.
       
  • Prediction of heat capacity for crystalline substances
    • Abstract: Publication date: June 2019Source: Calphad, Volume 65Author(s): Tilo Zienert, Olga Fabrichnaya An algorithm is derived that estimates the trend of heat capacity with temperature based on zero-Kelvin properties (V0,B0), the Debye temperature and the thermal expansion coefficient at the Debye temperature. The algorithm predicts not only the trend of heat capacity but also the temperature trend of the volume and the bulk modulus, which can be also included in new thermodynamic databases. Calculations of thermophysical properties take less then two minutes on a standard desktop CPU for a temperature range between 0 K and 2000 K. The algorithm is used to assess thermophysical properties of the intermetallic phases η (Fe2Al5), ϵ (Fe5Al8) and τ4 (FeAl3Si2) in comparison to calculated DFT results and experimental data. A method is shown how the melting point of a substance can be predicted using our algorithm in combination with low temperature cp and volume data.
       
  • Phase diagram of the system Ce-Rh-O
    • Abstract: Publication date: June 2019Source: Calphad, Volume 65Author(s): K.T. Jacob, Srilekshmi Muraleedharan Although important for catalytic applications, a phase diagram for the ternary system Ce-Rh-O is not found in the literature. Phase diagrams of most Ln-Rh-O systems show LnRhO3 with orthorhombic perovskite structure as the lone stable ternary oxide. Based on systematic trends in experimentally determined thermodynamic properties of eleven LnRhO3 compounds, the Gibbs energy of formation of CeRhO3 is evaluated as a function of temperature. For the reaction, 1/2 Ce2O3 (A-rare earth) + 1/2 Rh2O3 (ortho) → CeRhO3, ∆G°/J mol−1 = ‒69,336 + 5.26(T / K). The estimated data for CeRhO3 along with evaluated data for the binary Ce-Rh and data for binary oxides from the literature are used to compute the phase diagram for the system Ce-Rh-O at high temperature. Because of the significantly higher stability of CeO2-x compared to Ce2O3, the compound CeRhO3 is found to be unstable. A section of the phase diagram and an oxygen potential ‒ composition diagram for the system Ce-Rh-O at 1200 K are computed from thermodynamic data.Graphical abstractfx1
       
  • Phase equilibria and thermodynamic evaluation of the Fe-Ti-V-O system in
           air
    • Abstract: Publication date: June 2019Source: Calphad, Volume 65Author(s): Willem Dutoit Malan, Guven Akdogan, Pekka Taskinen, Johan Zietsman In this study, the iron-titanium-vanadium-oxygen (Fe-Ti-V-O) system in equilibrium with air was studied experimentally by high-temperature equilibration, quenching, scanning electron microscope and microprobe analysis coupled with critical assessment and thermodynamic evaluation. The properties of the liquid phase were successfully described with the quasichemical model by optimizing parameters only related to the Fe-Ti-O system; remaining parameters for the Fe-V-O and Ti-V-O sub-systems were adopted from recent optimisations. The model for the rutile and hematite solid solutions were described with the compound energy formalism. The ferropseudobrookite solid solution was modelled with a simple polynomial model to include a small solubility V2O5. A final set of self-consistent thermodynamic parameters was estimated within acceptable error limits. Calculated isothermal projections at 1000 °C, 1100 °C, 1200 °C, 1300 °C, and 1400 °C of the Fe-Ti-V-O system in equilibrium with air are presented and compared to experimental observations.
       
  • A CALPHAD approach to modelling of slag viscosities
    • Abstract: Publication date: June 2019Source: Calphad, Volume 65Author(s): K. Hack, G. Wu, E. Yazhenskikh, T. Jantzen, M. Müller A structure-based model recently developed for the fully liquid system SiO2–Al2O3–CaO–MgO–Na2O–K2O–FeO–Fe2O3 in the Newtonian range is presented in this paper and the methodology to modelling of the viscosity is outlined. In the model, the structural treatment of the various oxides in multicomponent oxide systems is discussed on the basis of the underlying non-ideal associate species model that was used to describe the Gibbs energy of the liquid. Both the temperature- and composition-induced structural changes of oxide melts is then described with a set of monomer associate species in combination with some specific larger structural units induced by the self- and inter-polymerisations of the associate species. On the other hand, the overall performance of the viscosity model will be demonstrated and discussed. One of the challenges of the viscosity behaviour in SiO2-based binary systems, the so called lubricant effect, is well described. The local viscosity maximum around the fayalite composition in the system FeO–SiO2 is also sufficiently described. The viscosity behaviour when substituting one network modifier for another at constant SiO2 contents is properly described. Moreover, the Al2O3-induced viscosity maximum is described, in which the position and magnitude of the viscosity maximum as a function of temperature and composition (charge compensation effect) are properly predicted. In addition to a good performance in describing the various challenging viscosity behaviours, the model parameters bear a clear physico-chemical meaning, which ensures a reliable prediction over the whole range of compositions and a broad range of temperatures and oxygen partial pressures (for iron oxide-containing systems). Finally, in combination with phase relations the model is employed to determine the blending proportions for coal slags according to a target viscosity value, as an application case.
       
  • Interdiffusion and atomic mobilities in fcc Ag–Mg and Ag–Mn
           alloys
    • Abstract: Publication date: June 2019Source: Calphad, Volume 65Author(s): Q.H. Min, Y.L. Liu, Y. Du, K.M. Cheng, B. Hu, S.H. Liu, H.X. Liu On the basis of Ag/Ag–Mg and Ag/Ag–Mn semi-infinite diffusion couples together with electron probe microanalysis technique, the interdiffusion coefficients in fcc phases of Ag–Mg and Ag–Mn alloys were measured between 873 and 1173 K via the Sauer-Freise method. A statistic method was applied to evaluate the errors of the identified interdiffusivities in terms of the propagation of errors. Based on available thermodynamic information and the experimental interdiffusion coefficients, the atomic mobilities for the fcc Ag–Mg and Ag–Mn systems are obtained by using the DICTRA software package. The quality of the assessed atomic mobilities was confirmed by the comprehensive comparisons between calculated concentration profiles and the experimental data.
       
  • An insight into using DFT data for Calphad modeling of solid phases in the
           third generation of Calphad databases, a case study for Al
    • Abstract: Publication date: June 2019Source: Calphad, Volume 65Author(s): Sedigheh Bigdeli, Li-Fang Zhu, Albert Glensk, Blazej Grabowski, Bonnie Lindahl, Tilmann Hickel, Malin Selleby In developing the next generation of Calphad databases, new models are used in which each term contributing to the Gibbs energy has a physical meaning. To continue the development, finite temperature density-functional-theory (DFT) results are used in the present work to discuss and suggest the most applicable and physically based model for Calphad assessments of solid phases above the melting point (the breakpoint for modeling the solid phase in previous assessments). These results are applied to investigate the properties of a solid in the superheated temperature region and to replace the melting temperature as the breakpoint with a more physically based temperature, i.e., where the superheated solid collapses into the liquid. The advantages and limitations of such an approach are presented in terms of a new assessment for unary aluminum.
       
  • Thermodynamic properties of tin: Part I Experimental investigation,
           ab-initio modelling of α-, β-phase and a thermodynamic description for
           pure metal in solid and liquid state from 0 K
    • Abstract: Publication date: June 2019Source: Calphad, Volume 65Author(s): A.V. Khvan, T. Babkina, A.T. Dinsdale, I.A. Uspenskaya, I.V. Fartushna, A.I. Druzhinina, A.B. Syzdykova, M.P. Belov, I.A. Abrikosov Thermodynamic data for crystalline white and grey tin were assessed using an extended Einstein model from 0 K. Ab-initio simulations in the framework of density functional theory (DFT) with the quasiharmonic approximation (QHA) were carried out to define the heat capacities for both phases of tin from 0 K up to room temperatures. Good agreement was observed between theoretical and experimental heat capacities, which makes it possible to combine theoretical and experimental data to determine the standard entropies. Data for the liquid phase were described using a two state model. During the assessment, careful analysis of the experimental data was carried out. In order to fulfil the need for a precise evaluation of So298 we needed to use an additional technique using multiple Einstein functions, which allows the experimental heat capacity and enthalpy data for the solid phase to be approximated accurately from 0 K up to the melting point and to estimate solid phase transition entropy and enthalpy which are difficult to measure due to a high activation barrier. Additional measurements of heat capacity were carried out where existing data were scarce.
       
  • Thermodynamic and experimental study of cobalt-based alloys designed to
           contain TiC carbides
    • Abstract: Publication date: June 2019Source: Calphad, Volume 65Author(s): Patrice Berthod, Mira Khair Two alloy compositions, {Co(bal.)-25Cr-0.25C-1Ti} and {Co(bal.)-25Cr- 0.50C-2Ti}, were studied using Thermo-Calc. In parallel the corresponding real alloys were elaborated by foundry and their microstructures, in their as-cast state or after a long stage at 1000 or 1200 °C, were characterized. Thermodynamic calculations and real experiments were globally in good agreement. They both demonstrate that the two alloys are highly refractory, that solidification starts by the crystallization of the alloy matrix in all cases and that all titanium carbides precipitate at the end of solidification and belong to a {matrix + TiC} eutectic compound. The TiC carbides remain stable during long exposure at elevated temperature, for both temperatures for the {0.50C-2Ti}-alloy but only at 1000 °C for the {0.25C-1Ti}-alloy. This observation suggests potential high mechanical properties of the {0.50C-2Ti}-alloy at elevated temperature. Many of the collected experimental data – temperature range of melting or solidification, microstructures stabilized at high temperature (natures, fractions and chemical compositions of the phases) – will be of interest for testing and improving databases.
       
  • Measurement of phase equilibria in Zr-Ni-Sc ternary system
    • Abstract: Publication date: June 2019Source: Calphad, Volume 65Author(s): L. Fan, J.Q. He, H.S. Liu, H.L. Peng, Z.P. Jin Phase relations in Zr-Ni-Sc ternary system were investigated experimentally through alloy sampling approach. Isothermal sections at 973, 1173, and 1273 K were constructed from the results of electron probe microanalysis (EPMA) and X-ray diffraction (XRD). No ternary phase has been detected in all these sections. Combining experiment and reasonable speculation, 12, 15 and 13 three-phase zones were obtained at 973, 1173 and 1273 K, respectively. Liquid region with a large composition range at 1273 K was found although its real boundary was estimated. The intermetallic compounds, Ni2Sc, NiSc and NiSc2, exhibit remarkable ternary solubility of Zr along the isoconcentration of Ni.
       
  • Combined experimental and thermodynamic modelling investigation of the
           distribution of antimony and tin between phases in the Cu-Fe-O-S-Si system
           
    • Abstract: Publication date: June 2019Source: Calphad, Volume 65Author(s): Denis Shishin, Taufiq Hidayat, Jiang Chen, Peter C. Hayes, Evgueni Jak The distributions of Sb and Sn between slag and matte in equilibrium with tridymite in the Cu-Fe-O-S-Si system at 1200 °C (1473 K) have been measured. The experimental technique involves high-temperature equilibration in sealed quartz ampoule, rapid quenching, and direct measurement of phase compositions using Electron Probe X-ray Microanalysis (EPMA). The closed system equilibration approach was used to minimize the evaporation of Sb and Sn from the samples. The experimentally-determined distribution coefficients of Sb and Sn between slag and matte were found to increase with increasing Cu concentration in matte above 40 wt%. The new data have been used to refine the computational thermodynamics model for the system containing Sb and Sn at dilute concentrations. The molten slag phase is described using the Modified Quasichemical Model in the Quadruplet Approximation. Liquid matte and metal phases were modelled using single solution built within the Modified Quasichemical Model in the Pair Approximation. The thermodynamic model can be used to assess and predict the deportments of Sb and Sn between the slag and matte phases in the high-temperature pyrometallurgical production, refining and recycling of copper.
       
  • Vaporization and caloric studies on yellow lead oxide PbO
    • Abstract: Publication date: June 2019Source: Calphad, Volume 65Author(s): Dietmar Kobertz The vaporization of pure yellow PbO(c) to provide reference data for lead titanate and other lead oxide containing compounds was investigated at temperatures of 810–1040 K. Thermodynamic quantities of sublimation and reaction enthalpies, and entropy were derived from the partial pressures of gaseous Pb, PbO, and O2 over pure yellow lead oxide. The experimental sublimation enthalpy of Pb from PbO(c) was ΔsubH930K0(Pb)=(206±5)kJmol−1, ΔsubH298K0(Pb)=(215±5)kJmol−1 and for PbO was ΔsubH930K0=(223±3)kJmol−1, ΔsubH298K0=(236±3)kJmol−1. The enthalpy, entropy and Gibbs energy of the following reactions were determined by 2nd and 3rd law analysis at T = 930 K:ΔrHT0 kJ mol−1ΔrST0J mol−1 K−1ΔrGT0 kJ mol−1PbO(c) = PbO(g)223 ± 395 ± 1137 ± 4
       
  • Vaporisation studies on Sn-Te-O system by Knudsen effusion mass
           spectrometry: Thermodynamic properties over (SnO2+SnTe3O8) biphasic region
           
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): V.V. Trinadh, P. Manikandan, Ashish Jain, T.S. Lakshmi Narasimhan, K. Ananthasivan Vaporisation studies along the pseudo binary line of SnO2–TeO2 (SnTe3O8 + SnO2) in the Sn-Te-O system were conducted by using Knudsen effusion mass spectrometry in the temperature range 843–968 K. SnTe3O8 vaporises incongruently and TeO2(g), TeO(g), Te2(g) and O2(g) were the neutral species observed over the equilibrium vapour. Partial pressure – temperature (p-T) relations of TeO2(g), TeO(g), Te2(g) over (SnTe3O8 + SnO2) “two phase” region were determined in the temperature range 843–968 K. Partial pressures of O2(g) were calculated by considering gas phase equilibrium reactions involving this species and TeO2(g), TeO(g), Te2(g). Using the p-T relations, enthalpy changes of the following reactions were evaluated: SnTe3O8(s) ⇌ SnO2(s) + 3TeO2(g); SnTe3O8(s) + 2TeO(g) ⇌ 4TeO2(g) + 0.5 Te2(g) + SnO2(s) and 0.5Te2(g) + TeO2(g) ⇌ 2TeO(g). Subsequently, the enthalpy and Gibbs energy of formation of SnTe3O8 phase at 298.15 K were deduced as ΔfHm° = −1613.7 ± 67.8 kJ mol−1 and ΔfGm° = −1386.7 ± 67.8 kJ mol−1. Knudsen effusion mass spectrometric studies on this system are being reported for the first time.
       
  • Measurement of thermodynamic activity of zirconia in yttria-stabilized
           zirconia electrolyte for solid oxide fuel cell application
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): V. Motalov, L. Bencze, X. Yin, R. Spatschek, L. Singheiser The Knudsen effusion mass spectrometry technique was applied to determine the activity of ZrO2 in 8 mol% yttria-stabilized zirconia (8YSZ) in the temperature range from 2200 K to 2500 K. The minor ZrO2+ ion current was used in calculations instead of the prevailing ZrO+ signal. The phase stability of the samples and their negligible interaction with the cell material was proved by XRD-analysis. The activity of ZrO2 was obtained to be 0.84 ± 0.04 independent of temperature. This fact allows estimating the same value of activity in the operating temperature range of solid oxide fuel cells (SOFCs).
       
  • Study of surface effects and catalytic properties of selected Ni-based
           bimetallic nanoparticles by Knudsen effusion mass spectrometry
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): Pavel Brož, Martina Hejduková, Vít Vykoukal, František Zelenka, Jiří Sopoušek, Jiří Buršík, Ondřej Zobač Surface effects and catalytic properties of CuNi, AgNi and AuNi bimetallic nanoparticles having diameter 10–30 nm were studied by Knudsen effusion mass spectrometry. The nanoalloys were prepared by solvothermal synthesis using oleylamine. Gradual removing of the organic substances, present on the nanoparticles from the synthesis, accompanied by their oxidation was observed during slow heating. The nanoparticle catalytic activity leading to the oxidation of the organic surface layer to CO2 in final step depends on the selected element in the Ni-based nanoalloy. The CuNi system shows the highest catalytic activity while the AuNi system the smallest one. As demonstrated, the KEMS method can be applied with advantage as a progressive tool for the evaluation of the oxidation catalytic activity of metal nanoparticles. The surface effects and the catalytic properties are discussed in view of our previous studies.Graphical abstractfx1
       
  • Vaporization studies on sodium oxide
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): Dietmar Kobertz The vaporization of pure Na2O(c) was investigated at temperatures of 900–1165 K with the method of Knudsen Effusion Mass Spectrometry (KEMS). Thermodynamic quantities of sublimation enthalpy, entropy and Gibbs energy were derived from the partial pressures of gaseous species Na and O2 over the pure sodium oxide reference samples. The sublimation enthalpies obtained for the reaction “Na2O = 2 Na(g) + ½ O2(g)” are for Na: ∆sub H10000 = 243 ± 4, 2nd Law, and 241 ± 3, 3rd law. For O2: ∆sub H10000 = 242 ± 2, 2nd Law, and 241 ± 2, 3rd law kJ mol−1. The Gibbs energy ∆sub G10000 and entropy ∆sub S10000 for sublimation were determined as 133 ± 5 kJ mol−1 and 110 ± 2 J mol−1 K−1 for sodium, and for O2: ∆sub G10000 =143 ± 4 kJ mol−1 and entropy ∆sub S10000 = 100 ± 2 J mol−1 K−1.From the equilibrium constant for the reaction Na2O(c) = 2Na(g) + ½ O2(g) the enthalpy ∆r H10000 resulted in 605 ± 6, 2nd law, and 611 ± 9 kJ mol−1, 3rd law. The Gibbs energy ∆r G10000 and entropy ∆r S10000 were deduced as 342 ± 9 kJ mol−1 and 269 ± 5 J mol−1 K−1.
       
  • Sublimation enthalpies of terbium and lutetium triiodides and formation
           enthalpies of their monomer and dimer molecules
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): V.B. Motalov, A.M. Dunaev, E.N. Mikheev, L.S. Kudin, M.F. Butman, K.W. Krämer The sublimation of terbium and lutetium triiodides was studied by Knudsen effusion mass spectrometry. The temperature dependencies of partial vapor pressures [atm] of the monomer and dimer molecules were determined as: lnp(TbI3) = – (31.74 ± 0.24)× 103/T + (21.43 ± 0.29) for 743–906 K; lnp(Tb2I6) = – (38.66 ± 0.38)× 103/T + (25.63 ± 0.46) for 786–906 K; lnp(LuI3) = – (31.48 ± 0.25)× 103/T + (22.28 ± 0.30) for 721–951 K; and lnp(Lu2I6) = – (36.95 ± 0.37)× 103/T + (25.21 ± 0.43) for 796–950 K. On the basis of a joint analysis of all literature data, the sublimation enthalpies [kJ mol–1] at 298.15 K are recommended as 281 ± 3 (TbI3), 346 ± 30 (Tb2I6), 279 ± 12 (LuI3), and 340 ± 30 (Lu2I6). The standard formation enthalpies [kJ mol–1] of the gaseous species at 298.15 K are –343 ± 4 (TbI3), –902 ± 30 (Tb2I6),–326 ± 12 (LuI3), and –870 ± 30 (Lu2I6).Graphical abstractfx1
       
  • Review KEMS 2012 till 2017
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): V.L. Stolyarova Review on the main results on high temperature behavior of inorganic systems and materials obtained by the Knudsen effusion mass spectrometry (KEMS) during last five years is presented. The available information on vaporization processes and thermodynamic properties of these systems found recently is discussed with the indication of its great importance for the developing of advanced high temperature materials that may be used in the various fields of modern technologies such as space, nuclear and optical industries.
       
  • Designing the composition and processing route of aluminum alloys using
           CALPHAD: Case studies
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): Jae-Gil Jung, Young-Hee Cho, Jung-Moo Lee, Hyoung-Wook Kim, Kwangjun Euh Aluminum alloys have been widely used in various industries, and continuous improvement in the properties of these alloys is required to meet consumer demand for high-performance devices. This review introduces five recent case studies where the CALPHAD method was applied in the development of high-performance Al alloys. CALPHAD calculations can reasonably predict the solidification microstructure of the Al-7Si-2Cu-1Mg alloy and 4343/3527/4343 brazing sheets, although, some deviations are caused by solid-state diffusion occurring during the actual solidification process. CALPHAD is useful for predicting the complex solidification behavior of Al-(12-18)Si piston alloys and Al-6Mg-9Si-10Cu-10Zn-3Ni natural composites, and the precipitation behavior of the Al matrix. The application of CALPHAD can also provide valuable information on the properties of Al alloys, such as that on the erosion of brazing sheets, fluidity of alloy melts, and refinement of secondary phases by melt treatment.
       
  • Precipitation kinetic model and its applications to Mg alloys
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): Manas Paliwal, In-Ho Jung Precipitation calculations for Mg alloys have been performed using an in-house precipitation model. The size distribution, number density and volume fraction of precipitates are complex functions of thermodynamics, nucleation, and diffusion kinetics dependent on solute composition and heat treatment parameters. The mathematical description and the numerical approach for the precipitation model are given in details. The precipitation model is dynamically linked to the FTlite light alloy database of the FactSage system for accurate input of thermodynamic data. The simulation results are compared with the available experimental data for Mg alloys such as Mg-Al, Mg-Zn and Mg-Al-Zn alloys to ascertain the predictive ability of the precipitate model. The precipitation model is also applied to deduce the precipitation kinetics in AZ91 + Ca alloy in comparison to conventional AZ91 alloy.
       
  • Neural network modelling on temperature coefficient of surface tension and
           its usage in melting point prediction of nanosized metal particles
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): Jaebong Yeon, Peiyuan Ni, Masashi Nakamoto, Toshihiro Tanaka Temperature coefficient of surface tension is a very important parameter to calculate phase diagrams of nanoparticle metal systems. In this paper, neural network calculation was for the first time used to evaluate the temperature coefficient. It shows that the constructed neural network can predict the temperature coefficient values for 37 metals, with the deviation from the averaged experimental measurements smaller than 25%. Furthermore, the neural network predictions were compared with the calculated values by using an empirical equation and it shows a better performance.
       
  • Synthesis, structure, stability and phase diagrams of selected bimetallic
           silver- and nickel-based nanoparticles
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): J. Pinkas, J. Sopoušek, P. Brož, V. Vykoukal, J. Buršík, J. Vřešťál An overview of the research on silver-based (Ag-Sn, Ag-Cu, Ag-Ni) and nickel-based (Cu-Ni, Au-Ni, Ni-Pt) bimetallic nanoparticles is presented. The investigated nanoparticles in this review are formed by elements that represent an important group of metals revealing fcc lattice under macro-sized conditions (with the exception of Sn). The effects of surface stabilizing layer of the alloy nanoparticles are also described. Our experience with synthesis, characterization and stabilization of alloy nanoparticles is summarized. The development of the nanoparticle synthesis represents an important and mandatory part of the experimental nanoalloy research. Main synthetic routes under focus are the low temperature borohydride reduction method, the high temperature oleylamine synthesis, and the high pressure method in autoclave. The subsequent structural studies are focused on both nanoparticle core and outer stabilizing layer. The cores of the nanoparticles are studied mainly by electron microscopy techniques. The phase stability of the nanoparticle core is investigated by thermal analysis. The Knudsen effusion mass spectrometry was applied for studies of stabilizing organic molecules that can be found on the surface of the nanoparticles. The presented overview of the experimental results is complemented by thermodynamic calculations of phase diagrams by the CALPHAD method.Graphical abstractfx1
       
  • The theoretical and experimental study of the Sb-Sn nano-alloys
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): A. Kroupa, V. Vykoukal, T. Káňa, A. Zemanová, J. Pinkas, M. Šob The Sb-Sn nano-alloys were prepared by wet synthesis and studied experimentally and by theoretical modelling. A combination of CALPHAD and ab initio method for modelling of the influence of particle size on the thermodynamic properties and phase equilibria in systems with complex, intermetallic phases was used to model the properties of the Sb-Sn system. The disappearance of the Sb2Sn3 phase was predicted for the equilibria with the particle radius below 80 nm. The experimental study carried out on Sb-Sn nanoalloys showed that Sb2Sn3 did not appear during the 1st run of DSC measurement, when the morphology of sample contains agglomerates of nanoparticles with the radius below 50 nm.
       
  • Formation energies of CdSe wurtzoid and diamondoid clusters formed from Cd
           and Se atomic clusters
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): Mudar Ahmed Abdulsattar, Hayder M. Abduljalil, Hussein Hakim Abed Cadmium Selenide thermodynamic formation energies at the molecular and nanoscale range are investigated using density functional theory. The investigation is performed using wurtzoid and diamondoid clusters that represent the wurtzite and zincblende structures at the molecular and nanoscale size range for a cluster number of atoms n ≤ 26. Cd and Se atomic clusters are optimized and used to provide component atomic cluster energies. Although both Cd and Se clusters at the nanoscale have different phases than bulk, the results show that Gibbs free energy, enthalpy, and entropy of formation of CdSe are close to their experimental bulk energies of formation within errors of experimental measurements. CdSe wurtzoids generally have higher absolute (more negative) Gibbs free energy of formation than CdSe diamondoids indicating more stable wurtzoid molecules which is also the case at bulk. The absolute Gibbs free energy of wurtzoids is also higher than experimental value (more negative) because of surface effects at the nanoscale. Enthalpy of formation indicates an exothermic reaction of Cd and Se clusters as is the case at bulk. The entropy of formation of all clusters is size-sensitive and converges towards bulk experimental measurements. Both wurtzoids and diamondoids members contain Cd13Se13 cluster which is the most investigated magic CdSe cluster.
       
  • Corrigendum to “Experimental and thermodynamic assessment of the
           Gd-Ti-Zr phase diagram” [Calphad 61 (2018) 237–245]
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): N. Mattern, J.H. Han, R. Nowak, O. Fabrichnaya, I. Kaban, O. Shuleshova, N. Sobczak
       
  • Update of thermodynamic descriptions of the binary Al-Sn and ternary
           Mg-Al-Sn systems
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): Ting Cheng, Ying Tang, Lijun Zhang In this paper, the thermodynamic descriptions of the binary Al-Sn and ternary Mg-Al-Sn systems were updated by using the CALculation of PHAse Diagram (CALPHAD) approach. For the Al-Sn sub-binary system, the solubility of Sn in (Al)fcc, which was ignored in the previous assessment, together with the recently experimental enthalpies of mixing in the liquid phase were taken into account. The calculated phase equilibria and thermodynamic properties in the binary Al-Sn system showed better agreement with more experimental information than those in the previous assessment. As for the Mg-Al-Sn ternary system, the newly updated thermodynamic descriptions of the Al-Sn system as well as those of the Mg-Al and Mg-Sn binary systems from the literature were adopted. A set of reliable and self-consistent thermodynamic parameters for the Mg-Al-Sn ternary system were obtained by reassessing the thermodynaic parameters of the liquid and solid solutions. Better agreement between the calculated results and the experimental data was achieved in the present assessent in comparison with the previous one. Furthermore, the Scheil-Gulliver solidification simulations were performed to predict the volume fractions of Mg2Sn, (Mg)hcp and γ (Mg17Al12) phases in the 9 as-cast Mg-Al-Sn alloys. The simulation results were compared with the experiental as-cast microstructures in the literature, which further validated the presently obtained thermodynamic descriptions.
       
  • Thermodynamic optimization of the binary systems PbO-SiO2, ZnO-SiO2,
           PbO-ZnO, and ternary PbO-ZnO-SiO2
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): M. Shevchenko, E. Jak Liquidus phase equilibrium data of the present authors for the PbO-ZnO and the PbO-ZnO-SiO2 systems (as a part of multicomponent PbO-ZnO-FeO-Fe2O3-Cu2O-CaO-SiO2), combined with phase equilibrium and thermodynamic data from the literature, have been used to obtain a self-consistent set of parameters of the thermodynamic models for all phases. The modified quasichemical model is used for the liquid slag phase. From these model parameters, the optimized ternary phase diagram is back calculated.
       
  • Atomic mobilities and diffusivities in fcc Co–X (X = Mn,
           Pt and Re) alloys
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): Huixin Liu, Yuling Liu, Yong Du, Qianhui Min, Jingfeng Zhang, Shuhong Liu The atomic mobilities of Co, Mn, Pt and Re in face-centered cubic (fcc) Co–X ( X = Mn, Pt and Re) alloys have been assessed as a function of temperature and composition by CALculation of PHAse Diagram (CALPHAD) approach. To validate the literature data and provide new experimental data, we prepared two fcc Co–Mn diffusion couples, which were used to determine the composition-dependent inter-diffusivities at 1073 and 1273 K. Based on various kinds of experimental diffusivities available in the literature and the experimental results in this work, the atomic mobilities in fcc Co–X (X = Mn, Pt and Re) alloys were obtained. Comprehensive comparisons between the calculated and measured diffusivities show that most of the experimental data can be well reproduced by the presently obtained atomic mobilities.
       
  • Experimental study and thermodynamic modelling of the Ag-Cd-In system
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): E. Fischer, K. Gajavalli, G. Mikaelian, P. Benigni, J. Rogez, A. Decreton, M. Barrachin In the case of a severe accident, the silver-indium-cadmium alloy which constitutes the absorber rods of a pressurized water reactor is liable to melt, interact with other materials as fuel cladding and then provoke early degradation of the core. The control rod elements also interact with fission products (in particular iodine), and may significantly affect their speciation and transport in the primary circuit as well as their behavior in the containment. The knowledge of the Ag-Cd-In ternary phase diagram is therefore of great importance to estimate the potential release of the absorber elements from the core. In this work, the thermodynamic modelling of the ternary Ag-Cd-In system has been carried out using the CALPHAD approach, based on available experimental data for phase diagram and thermodynamic properties. It takes into account additional experimental data related in particular to the liquidus temperatures in cadmium-rich region which are reported in this paper. A set of self-consistent thermodynamic parameters was optimized by the least-squares method using the TERGSS program [1]. A satisfactory agreement was obtained between the experimental data and the calculated results.
       
  • Experimental investigation of phase equilibria in the Ce-Fe-Ni system at
           950 and 750 °C
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): I. Fartushna, M. Mardani, A. Khvan, V. Cheverikin, M. Gorshenkov, A. Dinsdale The Ce-Fe-Ni system has been experimentally studied by microstructural analysis, electron microprobe analysis and X-ray diffraction over the whole concentration range. Isothermal sections at 950 and 750 °C for this system were constructed for the first time. The phase relations at 750 °C measured in this work are different from those published for 700 °C in particular because of the identification of a new binary phase Ce5Ni19. A continuous solid solution Ce(Fe,Ni)2 (MgCu2-type structure, cF24-Fd-3m), was found at 750 °C, with mutual substitution of Fe and Ni atoms. The liquid phase is present in the system both at 950 and 750 °C. Almost all binary-based phases at these temperatures show wide homogeneity regions and possess a constant Ce content.
       
  • Simulation of reaction-diffusion between substrate and coating during
           vapor deposition processes
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): A. Forslund, H. Larsson This work presents simulations of the solid state diffusion and reactions during deposition processes. Two cases are studied where the diffusion in and between coating and substrate is simulated. The processes simulated are in one case directed vapor deposition of Al and Ni on a precoated nickel-base superalloy, and in the other case chemical vapor deposition aluminization of a nickel-base superalloy. The simulations result in composition and phase-fraction profiles, which are presented and compared with experimental composition profiles. The simulation results are generally in good agreement with the experimental profiles.
       
  • Thermodynamics of copper-rich liquid Cu-Fe-Bi alloys determined by vapour
           pressure measurements
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): Andrzej Zajączkowski, Anna Suruło The Knudsen method was used for measurements of mass loss rate of dilute solutions of bismuth and iron in liquid copper, in the temperature range from 1378 to 1631 K. The produced experimental data were used in the optimization procedure aimed at determination of parameters of the thermodynamic model of the Cu-Fe-Bi system, linking the measured mass change rates with the thermodynamic properties of this system. The model applied in this procedure uses equations proposed by Pelton and Bale. They are an extension of a standard "dilute interaction parameter formalism" to non-dilute solutions. The obtained results made it possible to determine the value of the first order ternary interaction parameter:ɛBiFe = 19034/T-7.140.
       
  • Hypoeutectic Fe-Cr-Ni-Mo-C alloys additionally strengthened by the
           Frank-Kasper phases – Design by means of the CALPHAD approach
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): K. Wieczerzak, P. Bała In the present work, the concept of hypoeutectic Fe-Cr-Ni-Mo-C alloys additionally strengthened by the Frank-Kasper phases is shown. The alloys were designed using the CALPHAD approach in order to obtain a matrix with high corrosion resistance, similar to that of stainless steels, and good wear resistance at room and elevated temperatures, achieved by the precipitation of eutectic carbides and the Frank-Kasper phases. The main design strategy is to produce alloys with a narrow solidification range and precipitations of the Frank-Kasper phases within the dendrites after heat treatment in order to reduce the mean free path of the matrix. The effect of molybdenum on the evolution of intermetallic phases in the Fe-25Cr-xMo-0.8C system was determined. Additionally, the influence of nickel in the Fe-25Cr-5Mo-xNi-0.8C system on phase composition of the matrix, as well as the stability and volume fraction of intermetallic phases were investigated. Lever-Rule and the modified Scheil-Gulliver solidifications were simulated for selected five alloys in order to investigate the phase precipitation sequence. Particular emphasis during the discussion was placed on the influence of Mo and Ni on phase stability, as well as solidus and liquidus temperatures in the investigated systems.Graphical abstractfx1
       
  • Thermodynamic description of the Fe–Cu–C system
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): Leilei Chen, Zhenyu Zhang, Yeyan Huang, Junfeng Cui, Zixuan Deng, Houke Zou, Keke Chang As an addition to the iron-carbon alloys to improve their strength and corrosion resistance, copper is of great importance for iron and steel industry and the Fe–Cu–C system has been extensively investigated. Aiming at a thermodynamic basis to investigate the effect of Cu addition on the Fe–C system, the CALPHAD (CALculation of PHAse Diagrams) approach was utilized to assess the ternary Fe–Cu–C system including the binary Cu–C and Fe–C systems. The Redlich-Kister model, instead of the Modified Quasichemical Model (MQM) in previous work, was used to model the liquid phase. The parameters of the liquid phase in the Fe–C system from previous work have been slightly modified to fit better with new experimental data at high temperatures. One Fe/Cu/FeC0.05 (in wt%) diffusion couple was designed to further determine the phase equilibria of the ternary system. A set of self-consistent parameters for the Fe–Cu–C system was obtained after thermodynamic optimization. Good correspondence between calculated and experimental values of phase diagrams, thermodynamic properties, and liquidus projections has been achieved by the present thermodynamic description.
       
  • Phase equilibria of the Zn-Ti system: Experiments, first-principles
           calculations and Calphad assessment
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): Song-Mao Liang, Harish K. Singh, Hongbin Zhang, Rainer Schmid-Fetzer The phase equilibria and thermodynamic properties of the Zn-Ti system have been investigated by experiments, first-principles calculations and Calphad assessment. Differential scanning calorimetry measurement and microstructure characterization confirmed the Zn richest eutectic reaction to occur at 691.3 ± 0.4 K with about 0.27 at% Ti in the liquid. Density functional theory (DFT) calculations have been performed to calculate the finite-temperature heat capacity (Cp) of the intermetallics, providing also the absolute entropies. A full thermodynamic assessment of the Zn-Ti system has been performed by using the experimental and DFT results obtained in this work together with the collection of all available data from previous publications. In the present work, the Calphad results show good agreement not only in thermodynamic properties with DFT data, but also phase equilibria data with experimental results, especially in the Zn-rich side, which significantly improved from previous Calphad assessment. Phase diagrams including the gas phase have also been calculated and discussed.
       
  • Thermodynamic assessment of the Co-Ta system
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): Peisheng Wang, Jörg Koßmann, Ursula R. Kattner, Mauro Palumbo, Thomas Hammerschmidt, Gregory B. Olson The Co-Ta system has been reviewed and the thermodynamic description was re-assessed in the present work. DFT (density functional theory) calculations considering spin polarization were performed to obtain the energies for all end-member configurations of the C14, C15, C36 and μ phases for the evaluation of the Gibbs energies of these phases. The phase diagram calculated with the present description agrees well with the experimental and theoretical data. Considering the DFT results was essential for giving a better description of the μ phase at lower temperatures.
       
  • A thermodynamic assessment of the binary Fe-Mn system for the third
           generation of Calphad databases
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): Sedigheh Bigdeli, Malin Selleby In developing the third generation of Calphad databases, the next step after proper description of the unaries is to assess higher-order systems, i.e. binaries, ternaries etc. A new description of the Fe-Mn system is presented in this work, based on the Calphad approach. New models with a stronger physical basis are used to model the Gibbs energy of the phases. For this purpose, the revised magnetic model is used to fit the magnetic properties versus the most recent experimental and ab-initio data. An acceptable magnetic phase diagram is reproduced, and a reasonable fit for the phase diagram is achieved which will prevent possible artefacts in higher-order systems. The description is valid down to 0 K, which make it very useful as a starting point for modelling phase transformations occurring at low temperatures.
       
  • Thermodynamic assessment and glass forming ability prediction of the
           Zr-Fe-Cu system
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): Nan Zou, Hai-Jin Lu, Pei-Wen Gu, Jia-Yun Wang, Xuan-Kai Feng, Jian-Yun Shen, Yan-Lin He, Lin Li, Xiao-Gang Lu A thermodynamic assessment of the Zr-Fe-Cu system has been performed by using the first-principles calculations and the CALPHAD approach, which is capable of combining experimental and theoretical data of thermodynamics and phase equilibria. The isothermal sections at 853, 973, 1273, 1373 and 1473 K together with the mixing enthalpies of liquid phase at 1873 K were well evaluated, and a consistent set of thermodynamic parameters was obtained. The combination of three thermodynamic criteria has been applied to predict the composition dependency of the glass forming range (GFR), the glass forming ability (GFA) and the glass forming behaviour in the Zr-Fe-Cu system based on the thermodynamic description assessed in this work.
       
  • Diffusivities and atomic mobilities in bcc Ti-Zr-Nb alloys
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): Weimin Bai, Yueyan Tian, Guanglong Xu, Zhijie Yang, Libin Liu, Patrick J. Masset, Ligang Zhang Diffusion couples were prepared and annealed at 1373 K for 72 h and 1473 K for 48 h, respectively. The interdiffusion coefficients at the intersection composition were obtained using the Whittle and Green method and the ternary trace diffusion coefficients using Hall method. The experimental diffusion coefficients of Ti and Nb in bcc Ti-Zr-Nb system were assessed to develop an atomic mobility database. The calculated diffusion coefficients and composition profiles show good agreement with the experimental data.Graphical abstractfx1
       
  • Diffusion multiple study of the Co-Fe-Ni system at 800 °C
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): Yuan Yuan, Tao Chen, Dajian Li, Uta Gerhards, Fusheng Pan, Hans Seifert, Nele Moelans The Co-Fe-Ni system is a key system in a wide range of industrial applications. Knowledge of the thermodynamic and kinetic properties of the system is crucial for the alloy and process design. Although the system has been studied extensively, there remain several unexplained discrepancies between different literature data and, for mediate low temperatures, the information is scarce. In this work, a high throughput diffusion multiple approach was applied. The isothermal phase diagram section at 800 °C was determined using the Co-Fe-Ni multiple. The interdiffusion coefficients of the binary Co-Fe, Co-Ni, Fe-Ni systems and their composition dependence were calculated using the Sauer-Freise method based on the compositional profiles obtained from the diffusion multiple. Different from previous experimental results for mediate low temperature, our results coincide with the extrapolated Arrhenius temperature dependence from diffusion coefficient data at high temperature range. These observations are important for a better understanding and modelling of the interdiffusion behavior in this key alloy system.
       
  • Thermochemistry of some Zinc-Transition metal(TM) compounds and some
           Bismuth-TM compounds by high temperature direct synthesis calorimetry
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): S.V. Meschel, Philip Nash Intermetallic compounds such as Heusler and half-Heusler alloys have a number of interesting properties and are being developed for numerous applications. Such alloy development requires thermodynamic data and our work is aimed at providing such data to the scientific community.The standard enthalpies of formation of some zinc, bismuth and transition metal(TM) compounds have been measured by high temperature direct synthesis calorimetry at 1273 ± 2 K. The following values for the TM-Zn compounds are reported in kJ/mole of atoms:ScZn (-41.4 ± 3.0); PdZn (-37.0 ± 3.0); Hf2Zn (-9.8 ± 2.3); PtZn (-24.8 ± 2.5).Bismuth yields approximately 15–20 binary transition metal compounds and 12–20 binary compounds with lanthanide elements. Some of these compounds have semiconductor properties and as such could be potentially useful for industrial endeavors, which is particularly noted for PdBi, RhBi, HfBi and ZrBi.The standard enthalpies of formation of some Bi-TM compounds have been measured by high temperature direct synthesis calorimetry at 1273 ± 2 K. The following values are reported in kJ/mole of atoms; Ti2Bi (-15.2 ± 3.2); Y5Bi3 (-81.7 ± 2.5); ZrBi (-47.3 ± 3.1); BiRh (-17.2 ± 2.8);PdBi (-30.2 ± 3.1); BiPt (-17.8 ± 2.9). All the measurements refer to 298 K.The results for both the TM-Zn and the TM-Bi compounds are compared with available thermodynamic data from the published literature and with predicted values from both Miedema's semi-empirical model and from ab initio calculations.
       
  • Use of composition profiles near sigma phase for assessment of localized
           corrosion resistance in a duplex stainless steel
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): Rodrigo Magnabosco, Luara da Costa Morais, Daniella Caluscio dos Santos Pitting corrosion potential of a UNS S31803 duplex stainless steel (DSS) heat treated between 750 °C and 850 °C at different aging times was related to the extent of the Cr- and Mo-depleted areas at sigma-ferrite and sigma-austenite interfaces, estimated using DICTRA® simulations. It is possible to describe the sigma formation kinetics using a model that assumes a spherical region of austenite, with radius equivalent to the mean intercept of austenite islands, surrounded by ferrite. Composition profiles at sigma-ferrite and sigma-austenite interfaces were calculated, allowing the evaluation of the degree of depletion in Cr and Mo at sigma interfaces. There is a reduction of pitting potential with increase of the degree of depletion, characterized as the weighted sum of depleted areas in Cr and Mo composition profiles, making possible the assessment of the localized corrosion resistance of aged DSS through simulation of sigma phase formation.
       
  • Emulation of short-range ordering within the Compound Energy Formalism:
           Application to the calcite-magnesite solid solution
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): Xin Liu, Victor L. Vinograd, Sergii Nichenko, Dmitrii A. Kulik, Xiancai Lu, Björn Winkler Modern thermodynamic assessment studies of multicomponent systems typically employ the Compound Energy Formalism (CEF) to describe phases of variable composition, which may show effects of chemical ordering. In CEF, the ordering is described by splitting a crystallographic site in which several components can substitute for each other into subsites (sublattices) and by allowing fractional occupancies of these subsites to vary. This type of component redistribution over subsites (sublattices) is classified in solid solution theories as long-range order (LRO). A well-known shortcoming of CEF is the absence of a direct description of the effects of short-range order (SRO), which do not involve a redistribution of components between sublattices, but reveal themselves in various modes of clustering. Here we show that SRO can be taken into account within CEF as an additional (fictive) LRO effect driven by an extra negative excess enthalpy term. We argue that the mathematical form of this term should be constrained such that it ensures its vanishing both in low- and high-temperature limits. Including such a term into CEF allows a significant improvement in the description of phase relations in the system of calcite-magnesite, CaCO3-MgCO3. The modified CEF model with SRO emulation is made available in the GEM-Selektor software.
       
  • Experimental investigation and thermodynamic modeling of the
           Ni–Ti–V system
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): Lei Zou, Cuiping Guo, Changrong Li, Zhenmin Du The liquidus surface projection and isothermal section at 1273 K of the Ni–Ti–V system were established using X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy dispersion spectroscopy (EDS), electron probe micro-analyzer (EPMA) and differential thermal analysis (DTA) techniques. Six primary solidification regions and four invariant reactions were deduced in the liquidus surface projection, and six three-phase regions were derived in the isothermal section at 1273 K. No ternary compound was observed. According to the experimental results in the present work and literatures, the Ni–Ti–V system was modeled by means of the CALPHAD (CALculation of PHAse Diagram) method. Two-sublattice model (Ni,Ti)10(Ni,Ti)20 for binary σ phase was used, and the thermodynamic parameters of the σ and NiV3 phases in the Ni–V system was reassessed. Solution phases (liquid, fcc, bcc and hcp) were modeled with the substitutional solution model in the Ni–Ti–V system. The compounds, Ni3Ti, NiTi2, Ni3V and σ, were treated as (Ni,Ti,V)m(Ni,Ti,V)n, and B2 were treated as (Ni,Ti,V)0.5(Ni,Ti,V) 0.5Va3. A set of self-consistent thermodynamic parameters of individual phases was obtained.
       
  • Thermodynamic assessment and experimental investigation of the
           Al–Mn–Ni system
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): Alexander Walnsch, Mario J. Kriegel, Martin Rudolph, Mykhaylo Motylenko, Olga Fabrichnaya, Andreas Leineweber The ternary Al–Mn–Ni system plays an important role in the development of several structural and functional materials. To accomplish a purposeful development of alloys related to this system, an assessment of the thermodynamic parameters was performed. The assessment is based on literature data, as well as experimental investigations regarding the phase equilibria at 800 and 1000 °C. Moreover, the decomposition of the disordered A2 phase in the Mn-rich corner of the Al–Mn–Ni system was investigated by means of transmission electron microscopy and in-situ X-ray diffraction. Calculations based on the present description are in excellent agreement with the experimental data available in literature and reproduce the experimental results of the present work.Graphical abstractfx1
       
  • High-throughput thermodynamic computation and experimental study of
           solid-state phase transitions in organic multicomponent orientationally
           disordered phase change materials for thermal energy storage
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): Renhai Shi, Dhanesh Chandra, Wen-Ming Chien, Jingjing Wang Understanding the behavior of solid-solid phase transformation in phase change materials is crucial to design advanced thermal energy storage materials. It is however challenging to study the complex solid-solid phase transition and predict the optimal composition with reliable performances (such as high energy storage at invariant phase transition temperature) in multi-component systems based on traditional empirical rules. Therefore, the high-throughput computational framework by coupling thermodynamic calculation via CALPHAD (CALculation of PHAse Diagrams) methodology with key experimental validation is firstly proposed for ternary Pentaglycerine-Tris-(hydroxymethyl)-aminomethane-2-amino-2-methyl-1,3-propanediol (PG-TRIS-AMPL) system. A self-consistent thermodynamic database of PG-TRIS-AMPL ternary system has been firstly assessed and validated by experimental measurements from in-situ X-Ray-Diffraction (XRD) and Differential Scanning Calorimetry (DSC). Using this thermodynamic database via CALPHAD method, the high-throughput calculation has been performed to seek the optimal composition in PG-TRIS-AMPL ternary system. It is found that two optimal ternary compositions in PG-TRIS-AMPL ternary system are designed as PG0.33TRIS0.07AMPL0.60 (ΔHmax = 137.5 kJ/kg) during the 1st invariant reaction αAMPL-rich+βPG-rich→δTRIS-rich+γAMPL-rich at 326.5 K (53.35 °C) and PG0.58TRIS0.069AMPL0.351 (ΔHmax = 52.44 kJ/kg) during the 2nd invariant reaction γAMPL-rich+βPG-rich→δTRIS-rich+γ’PG-rich at 338.4 K (65.25 °C), respectively. This finding shows the good balance between high latent heat storage and low invariant phase transition temperature at mid-temperature (20–100 °C) application. Also, the present high-throughput computation approach can be extended into other multicomponent systems for various temperature range.Graphical abstractPrediction of optimal composition that has maximum energy storage in multi-component system via CALPHAD_based high-throughput calculation with key experimental validation.fx1
       
  • Phase diagrams and elastic properties of the Fe-Cr-Al alloys: A
           first-principles based study
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): Ruirui Wang, Xiao Zhang, Huaiyu Wang, Jun Ni The phase diagrams and elastic properties of the Fe-Cr-Al alloys in full-temperature and all-compositional ranges are calculated. By combining first-principles calculations and cluster variation method, binary and ternary phase diagrams are obtained. A new ternary ordered phase B32 which is different from ternary extension of binary phases appears in the ternary section around temperature of 600 K. The binary FeAl phases show an extremely high solubility for Cr, while the binary CrAl phase solid solution has a low solubility for Fe. By combining first-principles calculations and cluster expansion method, the bulk modulus, shear modulus and Poisson's ratio are calculated. The shear modulus and Poisson's ratio show a strong ordering dependency, while the ordering dependency in bulk modulus is weak. Disordered Fe-Cr alloys with a little Al solvent shows ductile property, the Al-rich corner has brittle property.
       
  • Experimental investigations and thermodynamic modelling of the
           Cr–Nb–Sn–Zr system
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): Paul Lafaye, Caroline Toffolon-Masclet, Jean-Claude Crivello, Jean-Marc Joubert This work reports the Calphad modelling of the Cr–Nb–Sn–Zr quaternary system. In a previous paper, the thermodynamic modelling of the Cr–Nb–Sn system was presented. Since no experimental data were available for the Cr–Sn–Zr ternary system, new experimental data are provided, within this study, on the isothermal section at 900 °C. A ternary C14 phase has been identified on the Sn-poor side of the phase diagram. In addition to these experimental data, Density Functional Theory (DFT) calculations are carried out in order to determine formation enthalpies of the stable and metastable compounds. At last, the Special Quasirandom Structures (SQS) method is jointly used with DFT calculations in order to estimate the mixing enthalpies of the A2 and A3 binary solid solutions. Finally, these experimental and calculated data in addition to those from the literature, are used as input data for the Calphad modelling of the Cr–Zr, Nb–Zr and Sn–Zr binary systems and the Cr–Nb–Zr, Cr–Sn–Zr and Nb–Sn–Zr ternary systems. A complete database for the Cr–Nb–Sn–Zr quaternary system is provided.
       
  • Thermodynamic assessment of the Ce-Fe-Sb system
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): Daiman Zhu, Chengliang Xu, Changrong Li, Cuiping Guo, Zhenmin Du The Ce-Fe-Sb ternary system is thermodynamically evaluated, based on all the presently available investigations of the isothermal sections and the liquidus projection. For all of the phases in the system, the expressions of Gibbs energies are proposed and the related parameters are optimized, after the systematic integration of the literature reported descriptions of the Ce-Fe and the Fe-Sb binary subsystems together with the present thermodynamic re-optimization of the Ce-Sb binary subsystem. The special attention is paid to the expression of the Gibbs energy of the liquid phase so as to get convergent the liquidus miscibility gap in the Fe-rich corner of the Ce-Fe-Sb ternary system at extraordinarily high temperature, which is easily caused by the very big difference between the values of the Gibbs energies of the terminal components Fe and CeSb. Using the Kaptay model to describe the interaction parameter between Ce and Sb, the excess Gibbs energy value approaches zero with increasing temperature, rather than decreases all the way down like using the polynomial expression, so that the difference of the Gibbs energy values between the terminal components Fe and CeSb can not become too big and the calculated liquid solution de-stabilization at extraordinarily high temperature can be avoided. For the isothermal sections, the liquidus projection and the liquidus mixing enthalpies, the comparisons between the results of computations with the data of experiments indicate that the present proposed modeling can finely reproduce the phase equilibria and the thermochemical properties of the Ce-Fe-Sb ternary system. The microstructure evolutions from high to low temperature for typical as-cast ternary alloys can be simulated by Scheil model for solidification analyses.
       
  • Thermodynamic optimization of the Ni–Al–Nd ternary system
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): Jinfa Liao, Yuehui Liao, Hang Wang, Ligang Zhang, Yue Ma Thermodynamic optimization of the Ni-Al-Nd ternary system and Al-Nd binary systems have been conducted in the present work. A self-consistent set of thermodynamic parameters for the Al-Nd binary system and Ni-Al-Nd ternary system have been optimized using CALPHAD method. Isothermal sections at 600 and 700 °C as well as the liquidus projection have been reproduced. Isopleths with 93 at% Al, 9 at% Ni and 3 at% Nd, have been calculated also. The calculated thermodynamic and phase equilibria data for both the binary and the ternary systems agree fairly well with the experimental data. This work can be used as multi-component thermodynamic database for Ni-based alloys.
       
  • Experimental study of the Be-C phase diagram
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): Kun Liu, Xiaozhong Huang, Zeyu Fu, Peisheng Wang, Yong Du, Haitang Yang The phase equilibria in the Be-C system were studied via experiment technique. Eleven key alloys were prepared by powder metallurgy method. X-ray diffraction (XRD), scanning electron microscopy (SEM) and differential thermal analysis (DTA) were used to determine phase compositions and phase transition temperatures. For the first time, the entire phase diagram for the Be-C system was obtained in the present work. The present work confirms that there is only one intermediate compound Be2C in this system. One allotropic transformation ((βBe) ↔ (αBe)) and two eutectic reactions (L ↔ (βBe) + Be2C and L ↔ Be2C + (C)) were determined.
       
  • Thermodynamic modeling of the chromium-yttrium-oxygen system
    • Abstract: Publication date: March 2019Source: Calphad, Volume 64Author(s): Huixia Xu, Ming Chen, Kaiming Cheng, Lijun Zhang, Yong Du Based on the CALPHAD (CALculation of PHAse Diagrams) method, a complete thermodynamic description of the Cr-Y-O ternary system is obtained in the present work. The thermodynamic properties of YCrO3 phase are critically assessed and the experimentally determined Cr2O3-Y2O3 quasi-binary section is reproduced. The current optimization results agree well with most of the experimental data in literature. The thermodynamic description of Cr-Y-O is then used to calculate the phase relations under different temperatures or oxygen partial pressures. The stability of the YCrO3 phase is discussed based on the calculation results.
       
  • Foreword: Thermodynamics of nanomaterials
    • Abstract: Publication date: Available online 4 February 2019Source: CalphadAuthor(s): Joonho Lee, Christopher A. Schuh, Jian Luo, Yu Zhong
       
 
 
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