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COMPUTER SCIENCE (1147 journals)                  1 2 3 4 5 6 | Last

Showing 1 - 200 of 872 Journals sorted alphabetically
3D Printing and Additive Manufacturing     Full-text available via subscription   (Followers: 11)
Abakós     Open Access   (Followers: 3)
Academy of Information and Management Sciences Journal     Full-text available via subscription   (Followers: 67)
ACM Computing Surveys     Hybrid Journal   (Followers: 23)
ACM Journal on Computing and Cultural Heritage     Hybrid Journal   (Followers: 8)
ACM Journal on Emerging Technologies in Computing Systems     Hybrid Journal   (Followers: 13)
ACM Transactions on Accessible Computing (TACCESS)     Hybrid Journal   (Followers: 4)
ACM Transactions on Algorithms (TALG)     Hybrid Journal   (Followers: 16)
ACM Transactions on Applied Perception (TAP)     Hybrid Journal   (Followers: 6)
ACM Transactions on Architecture and Code Optimization (TACO)     Hybrid Journal   (Followers: 9)
ACM Transactions on Autonomous and Adaptive Systems (TAAS)     Hybrid Journal   (Followers: 7)
ACM Transactions on Computation Theory (TOCT)     Hybrid Journal   (Followers: 11)
ACM Transactions on Computational Logic (TOCL)     Hybrid Journal   (Followers: 4)
ACM Transactions on Computer Systems (TOCS)     Hybrid Journal   (Followers: 18)
ACM Transactions on Computer-Human Interaction     Hybrid Journal   (Followers: 12)
ACM Transactions on Computing Education (TOCE)     Hybrid Journal   (Followers: 3)
ACM Transactions on Design Automation of Electronic Systems (TODAES)     Hybrid Journal   (Followers: 1)
ACM Transactions on Economics and Computation     Hybrid Journal  
ACM Transactions on Embedded Computing Systems (TECS)     Hybrid Journal   (Followers: 4)
ACM Transactions on Information Systems (TOIS)     Hybrid Journal   (Followers: 19)
ACM Transactions on Intelligent Systems and Technology (TIST)     Hybrid Journal   (Followers: 9)
ACM Transactions on Interactive Intelligent Systems (TiiS)     Hybrid Journal   (Followers: 4)
ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP)     Hybrid Journal   (Followers: 10)
ACM Transactions on Reconfigurable Technology and Systems (TRETS)     Hybrid Journal   (Followers: 7)
ACM Transactions on Sensor Networks (TOSN)     Hybrid Journal   (Followers: 8)
ACM Transactions on Speech and Language Processing (TSLP)     Hybrid Journal   (Followers: 10)
ACM Transactions on Storage     Hybrid Journal  
ACS Applied Materials & Interfaces     Full-text available via subscription   (Followers: 21)
Acta Automatica Sinica     Full-text available via subscription   (Followers: 3)
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: 24)
Advanced Science Letters     Full-text available via subscription   (Followers: 5)
Advances in Adaptive Data Analysis     Hybrid Journal   (Followers: 8)
Advances in Artificial Intelligence     Open Access   (Followers: 14)
Advances in Artificial Neural Systems     Open Access   (Followers: 4)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 5)
Advances in Computational Mathematics     Hybrid Journal   (Followers: 15)
Advances in Computer Science : an International Journal     Open Access   (Followers: 13)
Advances in Computing     Open Access   (Followers: 3)
Advances in Data Analysis and Classification     Hybrid Journal   (Followers: 53)
Advances in Engineering Software     Hybrid Journal   (Followers: 25)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 9)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 23)
Advances in Human-Computer Interaction     Open Access   (Followers: 19)
Advances in Materials Sciences     Open Access   (Followers: 16)
Advances in Operations Research     Open Access   (Followers: 11)
Advances in Parallel Computing     Full-text available via subscription   (Followers: 7)
Advances in Porous Media     Full-text available via subscription   (Followers: 4)
Advances in Remote Sensing     Open Access   (Followers: 35)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Advances in Technology Innovation     Open Access  
AEU - International Journal of Electronics and Communications     Hybrid Journal   (Followers: 8)
African Journal of Information and Communication     Open Access   (Followers: 6)
African Journal of Mathematics and Computer Science Research     Open Access   (Followers: 4)
Air, Soil & Water Research     Open Access   (Followers: 7)
AIS Transactions on Human-Computer Interaction     Open Access   (Followers: 6)
Algebras and Representation Theory     Hybrid Journal   (Followers: 1)
Algorithms     Open Access   (Followers: 9)
American Journal of Computational and Applied Mathematics     Open Access   (Followers: 3)
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: 2)
Anais da Academia Brasileira de Ciências     Open Access   (Followers: 2)
Analog Integrated Circuits and Signal Processing     Hybrid Journal   (Followers: 5)
Analysis in Theory and Applications     Hybrid Journal  
Animation Practice, Process & Production     Hybrid Journal   (Followers: 5)
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Data Science     Hybrid Journal   (Followers: 8)
Annals of Mathematics and Artificial Intelligence     Hybrid Journal   (Followers: 6)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of Software Engineering     Hybrid Journal   (Followers: 12)
Annual Reviews in Control     Hybrid Journal   (Followers: 6)
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: 2)
Applied Artificial Intelligence: An International Journal     Hybrid Journal   (Followers: 13)
Applied Categorical Structures     Hybrid Journal   (Followers: 2)
Applied Clinical Informatics     Hybrid Journal   (Followers: 1)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Applied Computer Systems     Open Access   (Followers: 1)
Applied Informatics     Open Access  
Applied Mathematics and Computation     Hybrid Journal   (Followers: 31)
Applied Medical Informatics     Open Access   (Followers: 9)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Soft Computing     Hybrid Journal   (Followers: 16)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4)
Architectural Theory Review     Hybrid Journal   (Followers: 3)
Archive of Applied Mechanics     Hybrid Journal   (Followers: 4)
Archive of Numerical Software     Open Access  
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4)
Artifact     Hybrid Journal   (Followers: 2)
Artificial Life     Hybrid Journal   (Followers: 5)
Asia Pacific Journal on Computational Engineering     Open Access  
Asia-Pacific Journal of Information Technology and Multimedia     Open Access   (Followers: 1)
Asian Journal of Computer Science and Information Technology     Open Access  
Asian Journal of Control     Hybrid Journal  
Assembly Automation     Hybrid Journal   (Followers: 2)
at - Automatisierungstechnik     Hybrid Journal   (Followers: 1)
Australian Educational Computing     Open Access  
Automatic Control and Computer Sciences     Hybrid Journal   (Followers: 3)
Automatic Documentation and Mathematical Linguistics     Hybrid Journal   (Followers: 5)
Automatica     Hybrid Journal   (Followers: 8)
Automation in Construction     Hybrid Journal   (Followers: 6)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 7)
Basin Research     Hybrid Journal   (Followers: 3)
Behaviour & Information Technology     Hybrid Journal   (Followers: 52)
Bioinformatics     Hybrid Journal   (Followers: 233)
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: 16)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 31)
Briefings in Bioinformatics     Hybrid Journal   (Followers: 45)
British Journal of Educational Technology     Hybrid Journal   (Followers: 119)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 10)
c't Magazin fuer Computertechnik     Full-text available via subscription   (Followers: 1)
CALCOLO     Hybrid Journal  
Calphad     Hybrid Journal  
Canadian Journal of Electrical and Computer Engineering     Full-text available via subscription   (Followers: 12)
Catalysis in Industry     Hybrid Journal   (Followers: 1)
CEAS Space Journal     Hybrid Journal  
Cell Communication and Signaling     Open Access   (Followers: 1)
Central European Journal of Computer Science     Hybrid Journal   (Followers: 5)
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: 7)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
CIN Computers Informatics Nursing     Full-text available via subscription   (Followers: 12)
Circuits and Systems     Open Access   (Followers: 13)
Clean Air Journal     Full-text available via subscription   (Followers: 2)
CLEI Electronic Journal     Open Access  
Clin-Alert     Hybrid Journal   (Followers: 1)
Cluster Computing     Hybrid Journal   (Followers: 1)
Cognitive Computation     Hybrid Journal   (Followers: 4)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 13)
Communication Methods and Measures     Hybrid Journal   (Followers: 11)
Communication Theory     Hybrid Journal   (Followers: 18)
Communications Engineer     Hybrid Journal   (Followers: 1)
Communications in Algebra     Hybrid Journal   (Followers: 3)
Communications in Partial Differential Equations     Hybrid Journal   (Followers: 3)
Communications of the ACM     Full-text available via subscription   (Followers: 47)
Communications of the Association for Information Systems     Open Access   (Followers: 18)
COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering     Hybrid Journal   (Followers: 3)
Complex & Intelligent Systems     Open Access  
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: 9)
Computación y Sistemas     Open Access  
Computation     Open Access  
Computational and Applied Mathematics     Hybrid Journal   (Followers: 2)
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: 2)
Computational and Theoretical Chemistry     Hybrid Journal   (Followers: 9)
Computational Astrophysics and Cosmology     Open Access  
Computational Biology and Chemistry     Hybrid Journal   (Followers: 12)
Computational Chemistry     Open Access   (Followers: 2)
Computational Cognitive Science     Open Access   (Followers: 1)
Computational Complexity     Hybrid Journal   (Followers: 4)
Computational Condensed Matter     Open Access  
Computational Ecology and Software     Open Access   (Followers: 8)
Computational Economics     Hybrid Journal   (Followers: 9)
Computational Geosciences     Hybrid Journal   (Followers: 12)
Computational Linguistics     Open Access   (Followers: 23)
Computational Management Science     Hybrid Journal  
Computational Mathematics and Modeling     Hybrid Journal   (Followers: 8)
Computational Mechanics     Hybrid Journal   (Followers: 4)
Computational Methods and Function Theory     Hybrid Journal  
Computational Molecular Bioscience     Open Access   (Followers: 2)
Computational Optimization and Applications     Hybrid Journal   (Followers: 7)
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: 13)
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Computer     Full-text available via subscription   (Followers: 78)
Computer Aided Surgery     Hybrid Journal   (Followers: 3)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 6)
Computer Communications     Hybrid Journal   (Followers: 10)
Computer Engineering and Applications Journal     Open Access   (Followers: 5)
Computer Journal     Hybrid Journal   (Followers: 8)
Computer Methods in Applied Mechanics and Engineering     Hybrid Journal   (Followers: 22)
Computer Methods in Biomechanics and Biomedical Engineering     Hybrid Journal   (Followers: 10)
Computer Methods in the Geosciences     Full-text available via subscription   (Followers: 1)
Computer Music Journal     Hybrid Journal   (Followers: 13)
Computer Physics Communications     Hybrid Journal   (Followers: 6)
Computer Science - Research and Development     Hybrid Journal   (Followers: 7)
Computer Science and Engineering     Open Access   (Followers: 17)
Computer Science and Information Technology     Open Access   (Followers: 10)
Computer Science Education     Hybrid Journal   (Followers: 12)
Computer Science Journal     Open Access   (Followers: 20)
Computer Science Master Research     Open Access   (Followers: 9)
Computer Science Review     Hybrid Journal   (Followers: 10)

        1 2 3 4 5 6 | Last

Journal Cover Calphad
  [SJR: 1.116]   [H-I: 44]   [0 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0364-5916
   Published by Elsevier Homepage  [3031 journals]
  • Design of Laves-phase-packed spheres in wear-resistant Cu alloy by
           controlled liquid immiscibility
    • Abstract: Publication date: September 2017
      Source:Calphad, Volume 58
      Author(s): Kouji Tanaka, Hajime Kato, Tadashi Oshima
      The designed liquid immiscibility of Cu-Ni-Fe-Mo-Si alloy led to separation of the spherical second liquid in the Cu-rich liquid, which solidified into coarse hard grains packed with Laves phase. The coarseness of hard grains was controlled not only by the repulsive interactions in Cu–Fe and Cu–Mo system, but also the refining effect of Ni and Si. CALPHAD analysis of the multicomponent system confirmed the correlation of the calculated fraction of the separated liquid with the observed grain dimensions. It also provided a powerful prediction of the precipitates constituting the hard grains. Almost all of the alloying effects on the observed microstructures were successfully interpreted based on equilibrium immiscibility calculations, although a reason for the refining of spheres with increasing Si remains unclear.
      Graphical abstract image

      PubDate: 2017-05-27T12:33:54Z
  • Thermodynamic assessment of the Al-C-Fe system
    • Abstract: Publication date: September 2017
      Source:Calphad, Volume 58
      Author(s): Weisen Zheng, Shuang He, Malin Selleby, Yanlin He, Lin Li, Xiao-Gang Lu, John Ågren
      The Al-C-Fe system was assessed in the framework of the CALPHAD approach. Through the critical review of thermochemical properties of liquid Al-Fe alloys, the binary Al-Fe description was revised to agree better with the experimental data. The partitioning model based on the Compound Energy Formalism (CEF) was utilized to describe the disordered and ordered bcc, fcc and κ phases. Moreover, ab initio calculations were performed to determine the enthalpies of formation of the ordered structures based on the bcc and fcc lattices in the binary Al-Fe and for the end-members of the κ phase in the ternary Al-C-Fe system. In order to simplify the database, the present work also employed a two-sublattice model to describe the B2 ordered phase in the Al-Fe system, which can be applied easily to diffusion simulations. Comprehensive comparison between the model-predicted and experimental data confirms that the present evaluation describe the Al-C-Fe system satisfactorily, especially the κ phase.

      PubDate: 2017-05-18T11:47:04Z
  • Experimental and thermodynamic study of the Mg-Sn-Ca-Sr quaternary system:
           Part I-Mg-Sn-Ca ternary system
    • Abstract: Publication date: September 2017
      Source:Calphad, Volume 58
      Author(s): Jian Wang, Jiajian Han, Beining Du, Yixiong Huang, Liyuan Sheng, Weifeng Rao, Cuiping Wang, Xingjun Liu
      Four key samples of the Mg-Ca-Sn ternary system in the Mg-rich region at 415 and 350°C have been determined using the Scanning Electron Microscopy (SEM) equipped with Energy Dispersive X-Ray Spectrometry (EDS). The existence of the CaMgSn ternary compound was confirmed in these two isothermal sections. Thermodynamic optimizations of the Ca-Sn binary system and Mg-Ca-Sn ternary system were carried out using the CALPHAD (Calculation of Phase Diagrams) technique. The Modified Quasichemical Model (MQM) was used for the liquid solution which exhibits a high degree of short-range ordering behavior in the liquid solution. The solid phases are modeled with the Compound Energy Formalism (CEF). Finally, a self-consistent thermodynamic database of Mg-Ca-Sn ternary system has been constructed in the present work, which would provide an efficient and convenient way to study and develop the new Mg-Sn based alloys.

      PubDate: 2017-05-13T11:33:23Z
  • Thermodynamic modeling of the PbX (X=S,Te) phase diagram using a five
           sub-lattice and two sub-lattice model
    • Abstract: Publication date: September 2017
      Source:Calphad, Volume 58
      Author(s): M.C. Peters, Jeff.W. Doak, W.-W. Zhang, J.E. Saal, G.B. Olson, P.W. Voorhees
      Five-sublattice and two-sublattice models have been built to describe the PbX (X=S,Te) semiconductors using the CALPHAD method. The five-sublattice model has three additional sublattices to explicitly model interstitials, electrons, and holes. The experimental literature has been critically reviewed and many high temperature carrier concentration results used in previous assessments have been shown to be unreliable. First-principle calculations for the formation energies of neutral defects and their respective ionization energies have also been incorporated into the models. The models show an improvement over previous assessments of PbTe and are the first time PbS has not been treated as a stoichiometric compound in a CALPHAD assessment.

      PubDate: 2017-05-13T11:33:23Z
  • Au-Ni nanoparticles: Phase diagram prediction, synthesis,
           characterization, and thermal stability
    • Abstract: Publication date: September 2017
      Source:Calphad, Volume 58
      Author(s): J. Sopoušek, A. Kryštofová, M. Premović, O. Zobač, S. Polsterová, P. Brož, J. Buršík
      The Au-Ni nanoparticles (NPs) were prepared by oleylamine solvothermal synthesis from metal precursors. The Au-Ni phase diagram prediction respecting the particle size was calculated by the CALPHAD method. The hydrodynamic size of the AuNi NPs in a nonpolar organic solvent was measured by the dynamic light scattering (DLS) method. The average hydrodynamic sizes of the nanoparticle samples were between 18 and 25nm. The metallic composition of the AuNi NP samples was obtained by inductively-coupled plasma atomic emission spectroscopy (ICP-OES). The metallic fraction inside AuNi NPs was varied Au-(30–70)wt%Ni. The steric alkylamine stabilization was observed. The individual AuNi NPs were investigated by transmission electron microscopy (TEM). The dry nanopowder was also studied. The structures of the aggregated samples were investigated by scanning electron microscopy (SEM). The AuNi NPs reveal randomly mixed face-centered cubic (FCC) crystal lattices. The phase transformations were studied under inert gas and air. The samples were studied by differential scanning calorimetry (DSC).

      PubDate: 2017-05-13T11:33:23Z
  • Thermodynamic model for prediction of binary alloy nanoparticle phase
           diagram including size dependent surface tension effect
    • Abstract: Publication date: September 2017
      Source:Calphad, Volume 58
      Author(s): Fatemeh Monji, Mohammad Amin Jabbareh
      Considering the size effect of nanoparticles on surface tension, a new CALPHAD type thermodynamic model was developed to predict phase diagram of binary alloy nanoparticle systems. In contrast to conventional model, the new model can be applied to the nanoparticles smaller than the critical size (5NM in radius). For an example, the model applied to Ag – Au binary system and the results were compared with experimental data as well as conventional CALPHAD model and molecular dynamics simulation results.

      PubDate: 2017-05-02T10:41:32Z
  • Thermodynamic and kinetic modeling of grain boundary equilibrium
           segregation of P in α-Fe
    • Abstract: Publication date: June 2017
      Source:Calphad, Volume 57
      Author(s): Y. Yang, S.-L. Chen
      Phosphorus is a primary contributor to interface fracture and embrittlement in steels because of its strong segregation tendency at grain boundaries (GBs). The lack of consistency in literature data imposes great difficulties in performing segregation modeling that is compatible with both the Langmuir-Mclean segregation theory and the thermodynamic description of the Bcc(Fe,P) phase. This work carefully evaluated experimental data for phosphorus segregation at GBs in α-Fe and provided a new formula for converting the auger electron spectroscopy (AES) peak height ratio to GBs. Based on newly assessed literature data, this work proposes that the major driving force for phosphorus segregation is the formation of Fe3P-type clusters at GBs, which is supported not only by the almost equivalent Gibbs energy of α_Fe using the Bcc(Fe,P) substitutional model and the Bcc(Fe,Fe3P, P) associate model, but also by the good agreement between thermodynamic/kinetic modeling results and experimental data.

      PubDate: 2017-04-25T10:20:07Z
  • Phase diagram of the quaternary system LiCl+MgCl2+KCl+H2O at 323.15K
    • Abstract: Publication date: June 2017
      Source:Calphad, Volume 57
      Author(s): Haitang Yang, Tengyu Liang, Dewen Zeng, Jianling Yue, Yong Du
      Solubility isotherms as well as the corresponding solid phases of the quaternary system LiCl+MgCl2+KCl+H2O and the eutectic points for the ternary systems LiCl+MgCl2+H2O, LiCl+KCl+H2O and MgCl2+KCl+H2O at 323.15 K have been elaborately determined by an isothermal equilibrium method. Five crystallization fields including two double salts (LiCl·MgCl2·7H2O(s) and KCl·MgCl2·6H2O(s)), two hydrate salts (MgCl2·6H2O(s) and LiCl·H2O(s)) and one single salt (KCl(s)) were detected in the quaternary system. The reliability of the experimental results were verified both by testing the phase diagram rule and comparing with the literature data. It was found that all of the results were accordance with the phase diagram rule, and moreover, the excellent agreement between the experimental data and the literature data was also obtained, which indicate that the solubility data obtained in this work are reliable. Based on the quaternary phase diagram, the example was provided for industrial application. The measured phase diagram reported in this work are the essential tool to guide industrial process of extracting Li from the salt lake brine containing MgCl2 and LiCl using KCl reagent.

      PubDate: 2017-04-18T09:53:59Z
  • Thermodynamic description of the Fe-Ca-O-S system
    • Abstract: Publication date: June 2017
      Source:Calphad, Volume 57
      Author(s): David Dilner, Malin Selleby
      In an effort to describe sulphur in steels, particularly in steelmaking, a thermodynamic description of the Fe-Ca-O-S and its subsystems is presented. The ionic two-sublattice liquid model has been used to describe all liquids. For the Fe-O-S part of the system the calculations reproduce available experimental data well. Experimental data is scarce in the Ca-O-S system and in the quaternary and we to trust that the system is well reproduced by extrapolation by previously assessed sub-systems.

      PubDate: 2017-04-11T09:32:54Z
  • Thermodynamic description of the Al−Fe−Nb system
    • Abstract: Publication date: June 2017
      Source:Calphad, Volume 57
      Author(s): Cuiping Guo, Tianfeng Wu, Changrong Li, Zhenmin Du
      The Al−Fe−Nb system was critically assessed by means of the CALPHAD technique. The solution phases (liquid, face-centered cubic and body-centered cubic) were modeled with the Redlich–Kister equation. The thermodynamic models of compounds Al13Fe4, Al2Fe and Al5Fe2 in the Al–Fe system and Al3Nb and AlNb3 in the Al–Nb system kept consistent with ones in the corresponding binary systems. The Fe2Nb and μ in the Fe–Nb system, Al8Fe5 in the Al–Fe system, and AlNb2 in the Al–Nb system were treated as the formulae (Al,Fe,Nb)2(Fe,Nb), (Al,Fe,Nb)1Nb4(Fe,Nb)2(Al,Fe,Nb)6, (Al,Fe,Nb)8(Al,Fe,Nb)5 and (Al,Nb)0.533(Al,Fe,Nb)0.333Nb0.134, respectively. B2 phase was treated as the ordered phase of bcc phase with the thermodynamic models (Al,Fe,Nb)0.5(Al,Fe,Nb)0.5(Va)3 and (Al,Fe,Nb)0.25(Al,Fe,Nb)0.25(Al,Fe,Nb)0.25(Al,Fe,Nb)0.25(Va)3. On the basis of optimized thermodynamic parameters of Al–Fe, Al–Nb and Fe–Nb systems in literature, the Al–Fe–Nb system was optimized in the present work. One set of self-consistent thermodynamic parameters of the Al–Fe–Nb system was obtained corresponding to B2 ordered phase with two kinds of thermodynamic model. Five experimental isothermal sections at 1073, 1273, 1423, 1573 and 1723K, and the liquidus surface projection were well reproduced in the present work.

      PubDate: 2017-04-04T09:16:02Z
  • Experimental investigation and thermodynamic calculation of the
           Fe–Si–Sn system
    • Abstract: Publication date: June 2017
      Source:Calphad, Volume 57
      Author(s): Xinming Wang, Bin Zhou, Zhiqiu Guo, Ya Liu, Jianhua Wang, Xuping Su
      Phase equilibrium of the Fe–Si–Sn ternary system was investigated using equilibrated alloys. The samples were characterized by means of scanning electron microscopy equipped with energy dispersive X–ray spectrometry and X–ray diffraction. Isothermal sections of the Fe–Si–Sn system at 700°C and 890°C each consists of 5 three–phase regions. No ternary compound was found at those two temperatures. The solubility of Sn in the Fe–Si binary phases and the solubility of Si in the Fe–Sn binary phases is limited. Furthermore, thermodynamic extrapolation of the Fe–Si–Sn system was carried out. Calculated solidification path and phase relationship agreed well with experimental results.

      PubDate: 2017-04-04T09:16:02Z
  • Modified embedded-atom interatomic potential for Fe-Ni, Cr-Ni and Fe-Cr-Ni
    • Abstract: Publication date: June 2017
      Source:Calphad, Volume 57
      Author(s): Changjun Wu, Byeong-Joo Lee, Xuping Su
      A semi-empirical interatomic potential formalism, the second-nearest-neighbor modified embedded-atom method (2NN MEAM), has been applied to obtaining interatomic potentials for the Fe-Ni, Cr-Ni and Fe-Cr-Ni systems using previously developed MEAM potentials of Fe and Ni and a newly revised potential of Cr. The potential parameters were determined by fitting the experimental data on the enthalpy of formation or mixing, lattice parameter and elastic constant. The present potentials generally reproduced the fundamental physical properties of the Fe-Ni and Cr-Ni alloys. The enthalpy of formation or mixing of the disordered phase at finite temperature and the enthalpy of mixing of the liquid phase are reasonable in agreements with experiment data and CALPHAD calculations. The potentials can be combined with already-developed MEAM potentials to describe Fe-Cr-Ni-based multicomponent alloys. Moreover, the average diffusivities in the unary, some binary and ternary alloys were simulated based on present potential. Good agreement is obtained in comparison with experimental data.

      PubDate: 2017-04-04T09:16:02Z
  • Estimation of thermodynamic properties of oxide compounds from polyhedron
    • Abstract: Publication date: June 2017
      Source:Calphad, Volume 57
      Author(s): Ting Wu, Elmira Moosavi-Khoonsari, In-Ho Jung
      This paper describes a method to calculate the thermodynamic properties like enthalpy, entropy and molar volume of oxide mineral phases from their constituent polyhedra. Based on thermodynamic properties of 48 silicate and 19 titanate compounds collected from the critically evaluated and optimized FactSage database, thermodynamic properties of 18 polyhedra were optimized by weighted multiple linear regression analysis. The optimized properties of constituent polyhedra accurately reproduced the entropy, enthalpy and molar volume of all compounds, and were used for the prediction of thermodynamic properties of ternary oxide compounds in titanate systems.

      PubDate: 2017-04-04T09:16:02Z
  • Modified embedded-atom method interatomic potentials for Mg-Nd and Mg-Pb
           binary systems
    • Abstract: Publication date: June 2017
      Source:Calphad, Volume 57
      Author(s): Ki-Hyun Kim, Byeong-Joo Lee
      Interatomic potentials for the Mg-Nd and Mg-Pb binary systems have been developed within the framework of the second nearest-neighbor modified embedded-atom method (2NN MEAM) formalism. The potentials describe a wide range of fundamental materials properties (thermodynamic, structural and elastic properties of compound and solution phases) of relevant systems in reasonable agreement with experimental data or first-principles and CALPHAD calculations. The applicability of the developed potentials to atomistic simulations on deformation behavior in Mg and its alloys is demonstrated by showing that the potentials reproduce related material properties reasonably and are transferable sufficiently.

      PubDate: 2017-03-28T08:51:09Z
  • Thermodynamic assessment of Fe–Ti–S ternary phase diagram
    • Abstract: Publication date: June 2017
      Source:Calphad, Volume 57
      Author(s): Kenji Hirata, Satoshi Iikubo, Hirokazu Fujimoto, Hiroshi Ohtani
      A thermodynamic analysis of the Fe-Ti-S ternary system was performed by incorporating first-principles calculations into the calculation of phase diagrams (CALPHAD) method. To evaluate the Gibbs energy, the Debye-Grüneisen model was applied for some sulfides of the Ti-S binary system. In addition, the cluster expansion and cluster variation methods were used for the solid solution phases in the Ti-S binary and (Fe,Ti)S phases. The calculated Ti-S binary phase diagram showed good agreement with the experimental results. The very low solubility of the Ti solid solution in the Ti-S system, as reported by Murray, agreed well with our calculated results. A binodal phase decomposition of the liquid phase was expected in the S-rich region. The Gibbs energy curve of (Fe,Ti)S between FeS and TiS was found to be convex downward. This is characteristic of an isomorphic solid solution, attributed to the attractive interaction between Fe and Ti in (Fe,Ti)S. The vertical phase diagram between FeS and TiS, obtained using the thermodynamic database, was in good agreement with the experimental results of Mitsui et al. The solubility products of (Fe,Ti)S have been experimentally estimated previously. The calculated solubility product agreed with the experimental value of TiS.

      PubDate: 2017-03-28T08:51:09Z
  • Thermodynamic modelling of the Cr-Nb-Sn system
    • Abstract: Publication date: June 2017
      Source:Calphad, Volume 57
      Author(s): Paul Lafaye, Caroline Toffolon-Masclet, Jean-Claude Crivello, Jean-Marc Joubert
      The Cr-Nb-Sn system has been studied experimentally, by first principles calculation and finally modeled with the Calphad method. The experimental study has been carried out on the Cr-Sn binary system to determine the solubility of Sn in the A2 (Cr) solid solution, but also in the Cr-Nb-Sn ternary system in order to determine phase equilibria of the isothermal section at 800°C and 1100°C. Besides, the formation enthalpies of all the ordered configurations of the C15 and A15 phases and the stoichiometric Nb6Sn5 and NbSn2 phases have been calculated using the Density Functional Theory (DFT). The mixing enthalpies of the A2 binary solid solutions have been estimated using the Special Quasirandom Structures (SQS). All these new experimental and calculated data have been taken into account for a new thermodynamic assessment of the three binary and the ternary systems.

      PubDate: 2017-03-12T21:13:18Z
  • First-principles calculations and thermodynamic modeling of the Sn-Ta
    • Abstract: Publication date: June 2017
      Source:Calphad, Volume 57
      Author(s): Cassie Marker, ShunLi Shang, Xuan L. Liu, Greta Lindwall, Zi-Kui Liu
      A thermodynamic description of the Sn-Ta system was developed using the CALPHAD (CALculation of PHAse Diagram) approach in combination with first-principles calculations. A positive enthalpy of mixing of the body centered cubic phase was predicted, using special quasirandom structures (SQS), indicating the tendency to form a miscibility gap. The finite temperature thermodynamic properties of Ta3Sn and TaSn2 were calculated by the Debye-Grüneisen model as well as phonon calculations using the supercell approach. The results from first-principles calculations along with the previously reported decomposition temperature of TaSn2, 868°K, were used to evaluate the Gibbs energy parameters of the TaSn2, Ta3Sn intermetallics and the liquid phase. No decomposition temperature of Ta3Sn has previously been reported in the literature but was predicted in this work to be 2884°K. The calculated phase diagram agrees well with available experimental information of the Sn-Ta system and also compares well with similar systems such as Nb-Sn and V-Sn.

      PubDate: 2017-03-12T21:13:18Z
  • Thermochemical analysis for the reduction behavior of FeO in EAF slag via
           Aluminothermic Smelting Reduction (ASR) process: Part Ι. Effect of
           aluminum on Fe & Mn recovery
    • Abstract: Publication date: Available online 6 March 2017
      Author(s): Jung Ho Heo, Joo Hyun Park
      We investigated Fe recovery from EAF slag by means of Aluminothermic Smelting Reduction (ASR) at 1773K, especially the quantitative effect of initial Al/FeO molar ratio upon the Fe recovery. Both calculated and experimentally measured system temperatures continuously increased with increasing initial Al/FeO molar ratio. Furthermore, to predict the reduction behavior we calculated variations in the slag composition by using FactSage™ 7.0 software. FeO and Al2O3 contents in molten slag varied sharply within the first 5min of the reaction and stabilized soon thereafter. The aluminothermic reduction of FeO appeared to proceed rapidly and in good stoichiometric balance, based upon the mass balance between the consumption of FeO and MnO (ΔFeO and ΔMnO) and the production of Al2O3 (∆Al2O3). Adding an optimal amount of Al (Al/FeO molar ratio ~ 0.8) yielded a Fe recovery of about 90%. Furthermore, the Mn could also be reduced from the EAF slag in the case of excess Al addition (Al/FeO≥0.8). The solid compound spinel (MgO·Al2O3) was precipitated from the slag during the FeO reduction, as confirmed by means of XRD analysis and thermochemical computations. Herein, the mechanism of ASR reaction between FeO in molten slag and Al is explained in several steps.

      PubDate: 2017-03-08T20:58:42Z
  • Thermochemical analysis for the reduction behavior of FeO in EAF slag via
           Aluminothermic Smelting Reduction (ASR) process: Part II. Effect of
           aluminum dross and lime fluxing on Fe and Mn recovery
    • Abstract: Publication date: Available online 6 March 2017
      Author(s): Jung Ho Heo, Joo Hyun Park
      We investigated Fe recovery from EAF slag by means of aluminothermic smelting reduction (ASR) at 1773K with Al dross as the reductant, especially the effect of the added amount of the fluxing agent CaO on the Fe recovery. The maximum reaction temperature calculated using FactSage™ 7.0 decreased with increasing CaO addition, but the experimentally measured maximum temperatures increased with increasing CaO addition. We calculated the amounts of various phases before and after Al dross addition under different conditions of added CaO. FeO and Al2O3 contents in molten slag sharply varied within the first 5min of the reaction, stabilizing soon thereafter. The aluminothermic reduction of FeO appeared to proceed rapidly and in good stoichiometric balance, based upon the mass balance between the consumption of FeO and MnO (ΔFeO and ΔMnO) and the production of Al2O3 (∆Al2O3). Iron recovery from EAF slag was maximized at about 90% when 40g of CaO was added to 100g slag. Furthermore, Mn could also be reduced from the EAF slags by the metallic Al in the Al dross reductant. The solid compounds of spinel (MgO∙Al2O3) and MgO were precipitated from the slag during the FeO reduction reaction, as confirmed by means of XRD analysis and thermochemical computations. To maximize Fe recovery from EAF slag, it is crucial to control the slag composition, namely to ensure high fluidity by suppressing the formation of solid compounds.

      PubDate: 2017-03-08T20:58:42Z
  • Thermodynamic modeling of the quaternary Al-Cu-Mg-Si system
    • Abstract: Publication date: June 2017
      Source:Calphad, Volume 57
      Author(s): Senlin Cui, In-Ho Jung
      Based on the critically evaluated thermodynamic and phase diagram information available in the literature, thermodynamic modeling of the Cu-Mg, Al-Cu-Mg, Al-Cu-Si, and Cu-Mg-Si systems were conducted using the CALPHAD (CALculation of PHAse Diagrams) technique. The liquid phase was described using the Modified Quasi-chemical Model (MQM), and the solid solution phases were modeled with the Compound Energy Formalism (CEF). Based on the newly obtained and the previously published thermodynamic descriptions of the subsystems, a set of self-consistent thermodynamic description for the Al-Cu-Mg-Si quaternary system was constructed. Comprehensive comparison between the calculated and measured thermodynamic and phase diagram information indicated that most of the reliable experimental data in the quaternary system can be satisfactorily reproduced by the presently obtained thermodynamic description. The optimized thermodynamic parameters can be used for the calculations of the phase diagram and thermodynamic properties of any composition and temperature range in the Al rich Al-Cu-Mg-Si quaternary system.

      PubDate: 2017-03-03T04:04:58Z
  • Experimental investigation and thermodynamic assessment of the Li-Sb
    • Abstract: Publication date: June 2017
      Source:Calphad, Volume 57
      Author(s): Fan Zhang, Shuhong Liu, Jianchuan Wang, Yong Du, Lixian Sun
      Sb and Sb-containing compounds have been attracting a great interest as promising alternative materials for commercial anodes and liquid batteries. The Li-Sb system was studies experimentally by investigating 6 alloys with X-ray diffraction measurement, scanning electron microscopy and electron probe microanalyses. Two binary phases Li2Sb and Li3Sb were confirmed to be stable in this system. Two invariant reactions L→(Sb)+Li2Sb and L+Li3Sb→Li2Sb were identified experimentally based on the microstructures of the as-cast alloys. The eutectic point was determined to be about 40at% Li. The enthalpies of formation for Li2Sb, αLi3Sb and βLi3Sb at 0K were calculated by means of density functional theory and the transition enthalpy between αLi3Sb and βLi3Sb was obtained. Then, the presently obtained results, combined with a critical review of literature data, were used to develop the thermodynamic description of the Li-Sb system by means of CALPHAD method. The liquid phase was treated as (Li, Li3Sb, Sb) using an associate model. The calculated phase diagram and thermodynamic properties can reproduce the available experimental data reasonably.

      PubDate: 2017-03-03T04:04:58Z
  • Evaluation of thermodynamic data and phase equilibria in the system
           Ca–Cr–Cu–Fe–Mg–Mn–S part I: Binary and quasi-binary subsystems
    • Abstract: Publication date: March 2017
      Source:Calphad, Volume 56
      Author(s): Tatjana Jantzen, Klaus Hack, Elena Yazhenskikh, Michael Müller
      The Ca–Cr–Cu–Fe–Mg–Mn–S system has been thermodynamically assessed using all available experimental data. The thermodynamic description of the high-temperature phase Chromium and Iron Pyrrhotite is described using a two-sublattice model which allows the description of the stability range of this phase in the binary Fe–S and Cr–S systems and also the solubility of such elements as Cu, Mg and Mn in the binary systems. Particular attention was given also to the phases Oldhamite and Digenite, which exhibit very wide solubility with respect to the metal elements. In this part of the report binary and quasi-binary subsystems are presented.

      PubDate: 2017-03-03T04:04:58Z
  • Experimental investigation and thermodynamic calculations of the
           Ag–Ga–Sn phase diagram
    • Abstract: Publication date: March 2017
      Source:Calphad, Volume 56
      Author(s): Milena Premović, Yong Du, Dusko Minić, Bo Sundman, Cong Zhang, Andy Watson, Dragan Manasijević, Aleksandar Djordjević
      Phase equilibria in the Ag–Ga–Sn ternary system have been studied experimentally by using differential thermal analysis (DTA), scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). Three vertical sections (Ag–Ga50Sn50, Ga–Ag50Sn50 and Sn–Ag50Ga50) and one isothermal section at 100°C were experimentally established. Based on available information in the literature and present experimental results, a thermodynamic description of the ternary Ag-Ga-Sn system has been developed by using CALPHAD method. Reasonable agreement between experimental data and the calculated phase diagrams is reached. The liquid projection and invariant equilibria have been calculated by using presently obtained thermodynamic parameters.

      PubDate: 2017-02-10T15:55:08Z
  • First-principles study of the Cu-Pd phase diagram
    • Abstract: Publication date: March 2017
      Source:Calphad, Volume 56
      Author(s): Feiyang Geng, Jacob R. Boes, John R. Kitchin
      The equilibrium phase diagram of a Cu-Pd alloy has been computed using cluster expansion and Monte Carlo simulation methods combined with density functional theory. The computed phase boundaries show basic features that are consistent with the experimentally reported phase diagram. Without vibrational free energy contributions, the order-disorder transition temperature is underestimated by 100K and the critical point is inconsistent with experimental result. The addition of vibrational free energy contributions yields a more qualitatively correct Cu-Pd phase diagram in the Cu rich region.

      PubDate: 2017-02-10T15:55:08Z
  • Diffusion study in bcc_A2 Fe-Mn-Si system: Experimental measurement and
           CALPHAD assessment
    • Abstract: Publication date: March 2017
      Source:Calphad, Volume 56
      Author(s): Shuwen Deng, Weimin Chen, Jing Zhong, Lijun Zhang, Yong Du, Li Chen
      Based on the recently developed numerical inverse method, high-throughput measurement of the composition-dependent interdiffusivity matrices in the bcc_A2 Fe-Mn-Si alloys at 1173, 1273 and 1373K was performed in the present work. To verify the reliability of the presently determined interdiffusivities, the ternary interdiffusivities evaluated by the traditional Matano-Kirkaldy method at the intersection points of the diffusion paths were employed to make a direct comparison. Subsequently, on the basis of the presently obtained interdiffusivities together with the thermodynamic descriptions for bcc_A2 phase in the Fe-Mn-Si system, atomic mobilities of Fe, Mn and Si in bcc_A2 Fe-Mn-Si alloys were assessed by means of DICTRA (DIffusion Controlled TRAnsformatim) software package. The comprehensive comparison between various calculated/model-predicted diffusion properties, including interdiffusivities, concentration profiles, interdiffusion fluxes and diffusion paths, and the experimental data indicates that most of the experimental data can be well produced by the presently obtained atomic mobilities. Moreover, the reliability of the present atomic mobilities was further validated by reproducing the experimental composition profiles which were not utilized in the assessment procedure.

      PubDate: 2017-02-10T15:55:08Z
  • Thermodynamic modeling of the Cu-Fe-Cr and Cu-Fe-Mn systems
    • Abstract: Publication date: March 2017
      Source:Calphad, Volume 56
      Author(s): Senlin Cui, In-Ho Jung
      All the thermodynamic and phase diagram information available in the literature on the Cu-Cr system, Cu-Fe-Cr system, and Cu-Fe-Mn system were critically evaluated and used in the thermodynamic optimization to obtain a set of consistent thermodynamic model parameters for the systems. The liquid solutions for the Cu-Cr, Cu-Mn, Fe-Cr, Cu-Fe-Cr, and Cu-Fe-Mn systems were described using the Modified Quasichemical Model (MQM) with pair approximation. The solid solution phases were modeled using the Bragg-Williams random mixing model. Accurate reproduction of all the reliable phase diagram and thermodynamic property data indicates the high reliability of the present thermodynamic optimizations.

      PubDate: 2017-02-10T15:55:08Z
  • Investigation of phase equilibria in the Ti-Co-Zr ternary system
    • Abstract: Publication date: March 2017
      Source:Calphad, Volume 56
      Author(s): Y. Zeng, L.L. Zhu, G.M. Cai, H.S. Liu, J.W. Huang, Z.P. Jin
      Isothermal sections of the Ti-Co-Zr ternary system at 1073K and 1173K were determined using Ti-Co-Zr diffusion triples and equilibrated alloys with optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscope (SEM) and electron probe micro-analysis (EPMA) techniques. A unknown ternary phase with composition of ~Ti31.3Co37.9Zr30.8 was observed to be stable at both 1073K and 1173K. Two continuous solid solutions Co2(Ti, Zr) and Co(Ti, Zr) were formed between the binary intermediate compounds Co2Ti (c) and Co2Zr (c) as well as between the CoTi and CoZr intermediate compounds, respectively. The solubility of Zr in the CoTi2 phase was nearly 55.0at% at both 1073K and 1173K, and the Co11Zr2 phase was proved to be non-existent at 1073K and 1173K. Liquid phase was observed at 1173K and exists with a wide range in the Ti-Zr-rich part.

      PubDate: 2017-02-10T15:55:08Z
  • The exponential excess Gibbs energy model revisited
    • Abstract: Publication date: March 2017
      Source:Calphad, Volume 56
      Author(s): George Kaptay
      The exponential model for the temperature (T) dependence of the excess Gibbs energy of liquid solutions within the framework of the Redlich-Kister polynomials is proven to be an efficient tool to avoid high-T artefacts, such as an artificial inverted miscibility gap, caused by the linear model. However, it has been claimed that the exponential model can lead to a low-T artefact, i.e. to the artificial low-T re-stabilization of the liquid solution. As shown here, this claim is un-supported for all the 15 binary systems studied so far by the exponential model in the literature. Still, the artefact might appear for other systems, or for lower temperatures, as the 15 systems were modelled at and above 298K. To make sure the low-T artefact does not appear, this paper introduces a new, low-T polynomial, which is matched with the exponential model at temperature T*, defined as the lowest liquidus temperature of the given system. The low-T model is described by a four parameter polynomial, obtained analytically from the two fitted parameters of the exponential model, ensuring that the four excess functions (the excess Gibbs energy, the heat of mixing, the excess entropy and the excess heat capacity) are continuous functions of T in the whole T-interval at any composition. When the complexity of the liquid alloy requires more than two semi-empirical parameters, the combined linear-exponential model should be used instead of the exponential model, with the same matching low-T polynomial. The inherently inconsistent nature of the recent LET function (see S.M. Liang, P. Wang, R. Schmid-Fetzer, Calphad 54 (216) 82–96) is discussed, as it was introduced to replace the exponential model. It is proven by the new simplified assessment of the Mg-Si system that the exponential model can be applied to this system without any artifact, contrary to the claim of Schmid-Fetzer et al., Calphad 31 (2007) 131–142.

      PubDate: 2017-02-03T15:37:48Z
  • Novel design of ferronickel smelting slag by utilizing red mud as a
           fluxing agent: Thermochemical computations and experimental confirmation
    • Abstract: Publication date: March 2017
      Source:Calphad, Volume 56
      Author(s): Hyun Sik Park, Min Chul Ha, Min Seok Kim, Jung Ho Heo, Joo Hyun Park
      The effect of red mud on the melting behavior of ferronickel slag was investigated in a laboratory-scale horizontal tube furnace. Melting and softening of slag samples fluxed with different amounts of red mud were examined by an in-situ visualization technique in the temperature ranges from 1673K to 1823K. FactSage™ 7.0 was used to perform thermodynamic calculations of the multi-component system of ferronickel slag and red mud. The liquid phase area was extended to lower temperatures by adding red mud, and this implied that red mud was an excellent flux. The primary solid phase field was confirmed to be dependent on the red mud content from X-ray diffraction measurements. Microscopic observations using a scanning electron microscope (SEM-EDX) confirmed that the primary solid phase changed from olivine to spinel with the addition of red mud.

      PubDate: 2017-02-03T15:37:48Z
  • Compositional screening of Zr-Nb-Mo alloys with CALPHAD-type model for
           promising bio-medical implants
    • Abstract: Publication date: March 2017
      Source:Calphad, Volume 56
      Author(s): J.S. Liang, L.B. Liu, G.L. Xu, X. Wang, L.G. Zhang, X. Shi, X.M. Tao
      The increasing demands for biological hard tissue replacements (HTR) press on the development of biomedical implant materials with good biological and mechanical compatibility. Three criteria of screening promising alloy compositions for bio-medical application were proposed: (1). High thermodynamic stability of biological compatible phase to avoid β_bcc→α_hcp and β_bcc→αʹ_hexagonal transformations. (2). Positive tetragonal shear elastic constant C′ and shear modulus to avoid the acoustic lattice softening induced structural transformation. (3). Appropriate Young's modulus of β_type alloy in or close to 10–30GPa to avoid the “stress-shielding effect”. To validate the proposed criteria, the initiatives of computational screening for candidate compositions of Zr-Nb-Mo alloys were implemented by CALPHAD based modeling. With the thermodynamic calculation, not only the plot of T 0 contour was employed to indicate the boundaries of non-classical decomposition of β_bcc phase and martensitic transformation, but also the composition range in which the alloys exhibit relative low critical driving force to trigger nucleation and growth of α_hcp was determined. The Young's modulus at body temperature and the contour of the vanishing tetragonal shear elastic constant were predicted within the entire composition range. By superimposing the composition ranges which individually satisfy the criteria, the “candidate composition” were determined as Zr-(18−24)Nb-(0−3)Mo (atom%). They are in good agreement with the composition in the experimentally fabricated biomedical alloys, thus further exemplify the reliability of the criteria. The proposed criteria together with the CALPHAD based computational methodology as a whole open up a new way to develop the potential bio-medical materials in the framework of Materials Genomes.

      PubDate: 2017-02-03T15:37:48Z
  • B2-disorder phase boundary calculations in Fe rich region of Fe-Si binary
           system with tetrahedron approximation of CVM
    • Abstract: Publication date: March 2017
      Source:Calphad, Volume 56
      Author(s): Naoya Kiyokane, Ying Chen, Takako Yamashita, Masayasu Nagoshi, Takaaki Iguchi, Tetsuo Mohri
      The phase boundary between B2 ordered and disordered phases in the Fe-rich region of the Fe-Si binary system is calculated by Cluster Variation Method (CVM). The configurational entropy is formulated within the tetrahedron approximation of CVM, and the internal energy is derived by Cluster Expansion Method (CEM) operated on a set of total energies calculated by DFT. The Debye Gruneisen model is employed to introduce the vibrational effect. The second order transition for the B2 order-disorder transition is confirmed, which is in agreement with the published phase diagram data and the results of previous CALPHAD calculations. The calculated transition temperature in the present study is higher around the stoichiometric composition and lower in the Fe-rich region compared to the experimental transition temperature. One reason for this overestimation and underestimation of the transition temperature may stem from the facts that the local atomic displacement and wide range atomic correlations are not considered in the present study. The transition temperature is also determined using Thermo-Calc software with the SSOL4 database. The transition temperature obtained by Thermo-Calc calculations accurately reproduces the experimental results. Hence, it is considered that the interaction parameters and the ordering parameters of CALPHAD free energy implicitly include the contributions of short range ordering and local atomic displacement.

      PubDate: 2017-02-03T15:37:48Z
  • Experimental study of the solid-liquid phase equilibria at the Si-rich
           region of the Cr-Nb-Si system
    • Abstract: Publication date: March 2017
      Source:Calphad, Volume 56
      Author(s): Y. Graz, N. David, J.M. Fiorani, S. Mathieu, S. Mathieu, G.C. Coelho, M. Vilasi
      High temperatures solid-liquid equilibria in the Cr-Nb-Si system are poorly known in the Si-rich area (>20% at Si). In this study, twenty-two as-cast samples were prepared and fully characterized using X-ray diffraction, scanning electron microscopy and quantitative energy dispersive spectrometry. Obtained results lead us to propose a new schematic layout of the liquidus projection of this system.

      PubDate: 2017-01-21T08:49:09Z
  • Thermodynamic modeling of Ti-Fe-Cr ternary system
    • Abstract: Publication date: March 2017
      Source:Calphad, Volume 56
      Author(s): Shusen Wang, Kun Wang, Guangyao Chen, Zhu Li, Ziwei Qin, Xionggang Lu, Chonghe Li
      Previous work of the Ti-Fe-Cr ternary system and its related binary systems are reviewed. Based on the thermodynamic descriptions of the Ti-Fe, Ti-Cr and Fe-Cr systems available in the literature, and also the ternary experimental data previously reported, the Ti-Fe-Cr ternary system is reassessed in this work by means of the Calphad method. Isothermal sections at 923K, 1073K and 1273K and three invariant reactions as well as the vertical section TiCr2-TiFe2 are calculated. It is shown that the present calculated results are in good agreement with most of the experimental data.

      PubDate: 2017-01-21T08:49:09Z
  • Data resources for thermophysical properties of metals and alloys, Part 1:
           Structured data capture from the archival literature
    • Abstract: Publication date: March 2017
      Source:Calphad, Volume 56
      Author(s): Boris Wilthan, Erik A. Pfeif, Vladimir V. Diky, Robert D. Chirico, Ursula R. Kattner, Kenneth Kroenlein
      In support of the continuous scientific and industrial need for accessible and high-quality thermophysical property data for metals and alloy systems, NIST/TRC is expanding its data archiving and critical evaluation activities to include this area. As part of this effort, a new data-capture software tool was developed. The new tool is described here in detail, including a list of supported properties, descriptions, and justification for capture of specific metadata. The key design features are: the separation of experimental results from author interpretations, a data-capture structure that mimics that of typical published experimental data, extensive and flexible capabilities for phase identification, well-structured capture of metadata related to sample characterization, and quantitatively defined uncertainties. This work (Part 1) marks the completion of an essential first step in the development of a freely available data resource of experimental and critically evaluated thermophysical properties for metallic systems. The next article in this series (Part 2) will describe the first implementation of data analysis tools, as well as channels for dissemination of results to users through online web services and offline software.

      PubDate: 2017-01-13T08:33:14Z
  • Phase equilibria in the Ge-Mn-Ti ternary system at 973K, 1073K and 1173K
    • Abstract: Publication date: March 2017
      Source:Calphad, Volume 56
      Author(s): Y. Sun, W.J. Zeng, K. Hu, H.S. Liu, G.M. Cai, Z.P. Jin
      Phase relationships in the Ge-Mn-Ti ternary system have been studied through alloy samples approach. Assisted with Electron Probe Microanalysis (EPMA) and X-ray diffraction (XRD) techniques, isothermal sections at 973K, 1073K and 1173K of this system were constructed and existence of 2 ternary phases, i.e. GeMnTi and Ge2MnTi, were confirmed. In addition, remarkable ternary solubilities in some binary compounds were detected, e.g. Ge in Mn2Ti and Mn in Ge5Ti6 can be up to 15at% and 50at% at 1173K, respectively. Furthermore, the substitution of Ti by Mn atoms in Ge5Ti6 was confirmed with Rietveld refinement results of solid solutions, Ge5(Mn0.30Ti0.70)6 and Ge5(Mn0.67Ti0.33)6.
      Graphical abstract image

      PubDate: 2017-01-13T08:33:14Z
  • First-principles study on segregation of ternary additions for
           MoSi2/Mo5Si3 interface
    • Abstract: Publication date: March 2017
      Source:Calphad, Volume 56
      Author(s): Koretaka Yuge
      We investigate segregation behavior of additional elements M (=Ni, Co, Ta) at the C11b/D8m interface for MoSi2–Mo5Si3 alloys, based on first-principles calculation. We first find energetically stable interface structure with interface energy of 0.08eV/Å2 (1.3J/m2). Based on the stable interface, segregation energy for additional elements is calculated for individual atomic layer, which is applied to Monte Carlo statistical simulation under grand-canonical ensemble to quantitatively predict interface segregation profile. We find that our simulation successfully captures the characteristics in measured segregation tendency of (i) similarity in strong segregation at interface both for Ni and Co compared with bulk composition while Ta does not exhibit interface segregation and (ii) stronger segregation for Ni than for Co. The present results indicate that measured segregated interface for MoSi2–Mo5Si3 alloys can be thermodynamically stable.

      PubDate: 2017-01-13T08:33:14Z
  • Phase equilibria, thermodynamics and microstructure simulation of
           metastable spinodal decomposition in c–Ti1−xAlxN coatings
    • Abstract: Publication date: March 2017
      Source:Calphad, Volume 56
      Author(s): Jingjing Zhou, Jing Zhong, Li Chen, Lijun Zhang, Yong Du, Zi-Kui Liu, Paul H. Mayrhofer
      Based on the experimental equilibrium data on spinodal decomposition in the literature together with the newly measured data in the present work, a complete metastable phase diagram for the pseudo-binary c–TiN/c-AlN system was constructed for the first time, from which a self-consistent thermodynamic description was then established by means of CALculation of PHAse Diagram (CALPHAD) method with the aid of first-principles computed free energies. By coupling with the CALPHAD thermodynamic database, two- and three-dimensional quantitative numerical simulations of microstructure evolution in metastable c–Ti1−xAlxN coatings during spinodal decomposition were performed using Cahn-Hilliard model. Three sets of diffusivity data available in the literature were carefully screened by comparing the simulated microstructures with the experimental ones, and one of them was chosen for the final simulations. The simulated composition wavelengths during spinodal decomposition at different temperatures agree with the experimental data. Moreover, the effect of the composition fluctuation on the microstructure evolution during spinodal decomposition was also comprehensively investigated.

      PubDate: 2017-01-06T07:54:15Z
  • Thermodynamic modelling of Ti-Zr-N system
    • Abstract: Publication date: March 2017
      Source:Calphad, Volume 56
      Author(s): Soumya Sridar, Ravi Kumar, K.C. Hari Kumar
      Thermodynamic modelling of Ti-Zr-N system is performed using Calphad method coupled with ab initio calculations. The energies of formation of stable and metastable end-members of sublattice formulations of solid phases in Zr-N system and enthalpy of mixing of the mixed nitride (Ti, Zr)N (δ) are calculated using ab initio method. Phonon calculations are used to compute the Gibbs energies of stoichiometric ZrN and the mixed nitride δ. With the aid of experimental thermochemical and constitutional data from the literature along with the results of ab initio calculations, thermodynamic optimization is carried out to obtain the Gibbs energy model parameters.

      PubDate: 2017-01-06T07:54:15Z
  • Critical reassessment of the Fe-Si system
    • Abstract: Publication date: March 2017
      Source:Calphad, Volume 56
      Author(s): Senlin Cui, In-Ho Jung
      The Fe-Si system has been studied extensively due to its importance in steelmaking and electrical-magnetic applications. Thermodynamic and phase diagram data of the Fe-Si system available in the literature were critically evaluated and re-optimized to improve the thermodynamic description of this system. Two sets of optimized model parameters were obtained to reproduce the available and reliable literature data. In each set of parameters, the liquid phase was described using the modified quasi-chemical model or the Bragg-Williams random mixing model. The A2/B2 and B2/D03 order-disorder transitions were also taken into account in the present study.

      PubDate: 2017-01-06T07:54:15Z
  • The Cr-Nb-Si system: Improved thermodynamic modelling and its use in
           simulation of Laves phase in steel
    • Abstract: Publication date: March 2017
      Source:Calphad, Volume 56
      Author(s): Aurélie Jacob, Erwin Povoden-Karadeniz, Ernst Kozeschnik
      Thermodynamic modelling of the Cr-Nb-Si ternary system is revised considering new findings in the binary Cr-Nb and extension to multicomponent systems. Thermodynamic model parameters of intermetallic phases are re-optimized based on density functional theory (DFT) calculations and experimental data. Particular attention was given to the transformations of Laves phase polytypes (i.e. C14 and C15). The calculated phase stabilities of technologically relevant Laves phase polytypes C14 and C15 are discussed. Their extension to multicomponent systems is tested for typical steel grades used in high-temperature applications. C14 is the dominant phase in high Cr ferritic steel.

      PubDate: 2016-12-27T07:12:57Z
  • Critical thermodynamic re-evaluation and re-optimization of the
           CaO–FeO–Fe2O3–SiO2 system
    • Abstract: Publication date: March 2017
      Source:Calphad, Volume 56
      Author(s): Taufiq Hidayat, Denis Shishin, Sergei A. Decterov, Evgueni Jak
      Comprehensive literature review, critical re-assessment and thermodynamic re-optimization of phase diagrams and thermodynamic properties of all phases have been carried out for the CaO–FeO–Fe2O3–SiO2 system. Thermodynamic assessments of this system were previously published, however some of them were incomplete or described only limited range of compositions. In addition, more recent important experimental data have been available after previous assessments. The Modified Quasichemical model is used to describe the Gibbs energy of the liquid slag. The monoxide, wollastonite, α-Ca2SiO4 and α’-Ca2SiO4 solid solutions are described using the random mixing Bragg-Williams model. Spinel, olivine, pyroxene and melilite solid solutions are modelled using sublattice model based on the Compound Energy Formalism. A set of optimized parameters for the thermodynamic models has been obtained which reproduces all available experimental data within the experimental uncertainties from sub-solidus to above the liquidus temperatures at all compositions and atmosphere conditions.

      PubDate: 2016-12-07T04:48:45Z
  • Critical evaluation and thermodynamic assessment of the MgO-V2O5 and
           CaO-V2O5 systems in air
    • Abstract: Publication date: March 2017
      Source:Calphad, Volume 56
      Author(s): Zhanmin Cao, Nai Wang, Wei Xie, Zhiyu Qiao, In-Ho Jung
      The MgO-V2O5 and CaO-V2O5 systems in air have been critically evaluated and thermodynamically assessed based on available experimental data. The liquid phase is described by the modified quasichemical model and all intermediate phases are treated as stoichiometric compounds. A set of self-consistent model parameters for all phases in both systems is obtained. The experimental phase equilibria and thermodynamic data in air are well reproduced within experimental error limits.

      PubDate: 2016-12-07T04:48:45Z
  • Experimental investigation of phase relations in Al-Co-Y ternary system
    • Abstract: Publication date: March 2017
      Source:Calphad, Volume 56
      Author(s): Yurong Jiang, Xian Li, Yun Jiang, Shuaixiong Huang, Xi Shi, Cun Mao, Ligang Zhang, Libin Liu, Feng Zheng
      Phase relations in the Al-Co-Y ternary system at 1173K have been established by means of scanning electron microscopy (SEM), electron probe microanalysis (EPMA) and X-ray diffraction (XRD) techniques. Isothermal section at 1173K of this system was constructed, which consists of 27 three-phase regions and 50 two-phase regions (27wider+23line). The ternary compound τ5-AlCo2Y2 has been confirmed to exist and the crystal structure has been preliminarily analyzed with pattern indexing method as well. The intermetallic phase Co2Y, Co3Y, Co7Y2, Co5Y, Co17Y2, Al2Y, τ4-AlCoY and τ5-AlCo2Y2 were expressed as the formula of AlxCo2−xY, AlxCo3−xY, AlxCo7−xY2, AlxCo5−xY, AlxCo17−xY2, Al2−xCoxY, Al1+xCo1−xY and Al1−xCo2+xY2, respectively.
      Graphical abstract image

      PubDate: 2016-11-30T04:39:23Z
  • Thermodynamic descriptions of the Sb/Ge unary systems
    • Abstract: Publication date: March 2017
      Source:Calphad, Volume 56
      Author(s): Chengliang Xu, Changrong Li, Shuanglin Chen, Cuiping Guo, Zhenmin Du, Yue Yuan
      This paper focuses on the theoretical descriptions of the Gibbs energies concerning the unary systems of Antimony and Germanium. The Gibbs energy expressions of the vapor phase and the condensed phases are included in order to study the influences of temperature and pressure on the phase equilibrium status. The vapor phase is treated as a real solution of the constituent species by considering the fugacity coefficients of gas species in order to assure the reasonability of the P-T (Pressure-Temperature) diagrams at high pressure. The condensed phases are described in the light of the pressure dependent Murnaghan equation which is presented as a pressure dependent contribution Gpres in the present work. The pressure correction factors for the condensed phases include the molar volume, the parameters of the variations of the thermal expansivity and the compressibility with temperature, and the variation of the bulk modulus with pressure. The related parameters of the vapor phase and all the condensed phases are thermodynamically optimized for Sb and Ge unary systems, on the basis of experimental measurements in literature. The calculated results of the P-T relations and the P-V (Pressure-Volume) curves agree well with the experimental data. The calculated slope of liquid-solid coexistence curve at the low pressure of the P-T phase diagram of Sb unary system follows Clausius-Clapeyron equation. The calculated heat capacity curves of condensed phases of Sb and Ge are analyzed and discussed to assure the reasonability of the thermodynamic models described in the paper. The present thermodynamic descriptions of both unary systems are of great benefit to the preparation process of the CoSb3-based thermoelectric materials, especially for the prevention of the volatilization of Sb containing vapor species and the determination of the sintering temperature under certain pressure.

      PubDate: 2016-11-30T04:39:23Z
  • Phase formations in low density high entropy alloys
    • Abstract: Publication date: March 2017
      Source:Calphad, Volume 56
      Author(s): Weihua Sun, Xuejun Huang, Alan A. Luo
      Phase formations in high entropy alloys (HEAs) with at least two light elements in literature are predicted by CALPHAD (CALculation of PHAse Diagrams) thermodynamic calculations and the results are compared with experimental observations. The comparison suggests that the applicability of traditional CALPHAD calculations depends on the manufacturing processes of HEAs. Factors such as solute trapping, energies of defects need to be considered while predicting phases in HEAs prepared by non-equilibrium processes. The effects of light elements (Al, Ti, Si, alkali and alkaline earth metals) on the phase formations in HEAs are discussed. Especially, intermetallics predicted for Si-containing HEAs by traditional CALPHAD calculation can be suppressed in rapid solidification process, due to the solute trapping effect. Mg or other alkali and alkaline earth metals can lead to the formations of various intermetallics in HEAs prepared by conventional casting, but could be dissolved into solid solutions by non-equilibrium processes such as mechanical alloying. It is proposed that non-equilibrium processes may be an effective way to introduce light elements Si, alkali and alkaline earth metals into HEAs.

      PubDate: 2016-11-30T04:39:23Z
  • An assessment of the Ca-V-O system
    • Abstract: Publication date: March 2017
      Source:Calphad, Volume 56
      Author(s): Yang Yang, Huahai Mao, Malin Selleby
      The Ca-V-O system is studied with an emphasis on the following oxide sub-systems: CaO-V2O5, CaO-V2O3, V2O5-CaV2O5 and CaO-V2O5-VO2. The aim of the present assessment is to obtain a thermodynamic description of the Ca-V-O system. The compound energy formalism was used to describe the liquid by applying the ionic two-sublattice model and the β-bronze phase CaxV2O5 (0.17≤x≤0.33) using a three-sublattice model. Phase equilibria and thermodynamic properties were critically evaluated using the CALPHAD approach and a consistent set of thermodynamic model parameters was obtained. Satisfactory agreement between calculated and experimental values is achieved.

      PubDate: 2016-11-30T04:39:23Z
  • Experimental and thermodynamic study of the role of titanium in the
           microstructural and thermal properties of cast Ni–Cr–C–Ti alloys
    • Abstract: Publication date: March 2017
      Source:Calphad, Volume 56
      Author(s): Patrice Berthod, Estelle Kretz, Floriane Allègre
      Three compositions of the {Ni–25Cr–0.25 or 0.50C–1 or 2Ti}-type were studied by thermodynamic calculations for anticipating their melting temperature ranges and their microstructures at 1200°C. In parallel the corresponding alloys were synthesized by classical foundry and subjected to Differential Thermal Analysis and exposures at 1200°C followed by metallographic characterization. Calculations and experiments are globally consistent concerning the melting range temperatures, the microstructures in the as-cast state and after aging at 1200°C. Good agreement was also found concerning the carbides fractions and the matrixes’ chemical compositions.

      PubDate: 2016-11-30T04:39:23Z
  • PrecHiMn-4—A thermodynamic database for high-Mn steels
    • Abstract: Publication date: March 2017
      Source:Calphad, Volume 56
      Author(s): Bengt Hallstedt, Alexandra V. Khvan, Bonnie B. Lindahl, Malin Selleby, Shuhong Liu
      This paper concerns a Calphad database that was developed to describe precipitation of cubic carbides and nitrides (V, Nb and Ti) in high manganese steels and to describe phase equilibria in high manganese steels with high aluminium content. The database has also been shown to be useful for calculations on medium manganese steels and low-density steels with varying aluminium additions. Thus the database covers a significant fraction of the steels that are termed advanced high strength steels (AHSS) of the second and third generation. A number of systems were assessed (or reassessed) for the database, namely Fe–Mn–Al, Fe–Mn–C, Fe–Nb, Mn–Nb, Fe–Mn–Nb, Fe–Nb–V, Fe–Nb–C, Mn–Nb–C, Fe–Mn–Nb–C, Nb–N, Fe–Mn–Nb–N. The remaining systems were taken from published assessments. The database covers the elements Fe, Mn, Al, Si, V, Nb, Ti, C and N.

      PubDate: 2016-11-30T04:39:23Z
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