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ENGINEERING (1209 journals)                  1 2 3 4 5 6 7 | Last

Showing 1 - 200 of 1205 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 7)
3D Research     Hybrid Journal   (Followers: 19)
AAPG Bulletin     Hybrid Journal   (Followers: 7)
AASRI Procedia     Open Access   (Followers: 15)
Abstract and Applied Analysis     Open Access   (Followers: 3)
Aceh International Journal of Science and Technology     Open Access   (Followers: 2)
ACS Nano     Full-text available via subscription   (Followers: 252)
Acta Geotechnica     Hybrid Journal   (Followers: 7)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 2)
Acta Scientiarum. Technology     Open Access   (Followers: 3)
Acta Universitatis Cibiniensis. Technical Series     Open Access  
Active and Passive Electronic Components     Open Access   (Followers: 7)
Adaptive Behavior     Hybrid Journal   (Followers: 11)
Adıyaman Üniversitesi Mühendislik Bilimleri Dergisi     Open Access  
Adsorption     Hybrid Journal   (Followers: 4)
Advanced Engineering Forum     Full-text available via subscription   (Followers: 6)
Advanced Science     Open Access   (Followers: 5)
Advanced Science Focus     Free   (Followers: 3)
Advanced Science Letters     Full-text available via subscription   (Followers: 9)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 7)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 17)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 5)
Advances in Complex Systems     Hybrid Journal   (Followers: 7)
Advances in Engineering Software     Hybrid Journal   (Followers: 26)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 16)
Advances in Fuzzy Systems     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 11)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 22)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 26)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 9)
Advances in Natural Sciences: Nanoscience and Nanotechnology     Open Access   (Followers: 30)
Advances in Operations Research     Open Access   (Followers: 11)
Advances in OptoElectronics     Open Access   (Followers: 5)
Advances in Physics Theories and Applications     Open Access   (Followers: 12)
Advances in Polymer Science     Hybrid Journal   (Followers: 41)
Advances in Porous Media     Full-text available via subscription   (Followers: 4)
Advances in Remote Sensing     Open Access   (Followers: 40)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Aerobiologia     Hybrid Journal   (Followers: 2)
African Journal of Science, Technology, Innovation and Development     Hybrid Journal   (Followers: 5)
AIChE Journal     Hybrid Journal   (Followers: 32)
Ain Shams Engineering Journal     Open Access   (Followers: 5)
Akademik Platform Mühendislik ve Fen Bilimleri Dergisi     Open Access   (Followers: 1)
Alexandria Engineering Journal     Open Access   (Followers: 1)
AMB Express     Open Access   (Followers: 1)
American Journal of Applied Sciences     Open Access   (Followers: 28)
American Journal of Engineering and Applied Sciences     Open Access   (Followers: 11)
American Journal of Engineering Education     Open Access   (Followers: 9)
American Journal of Environmental Engineering     Open Access   (Followers: 17)
American Journal of Industrial and Business Management     Open Access   (Followers: 23)
Analele Universitatii Ovidius Constanta - Seria Chimie     Open Access  
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of Regional Science     Hybrid Journal   (Followers: 8)
Annals of Science     Hybrid Journal   (Followers: 7)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2)
Applicable Analysis: An International Journal     Hybrid Journal   (Followers: 1)
Applied Catalysis A: General     Hybrid Journal   (Followers: 6)
Applied Catalysis B: Environmental     Hybrid Journal   (Followers: 18)
Applied Clay Science     Hybrid Journal   (Followers: 5)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 4)
Applied Nanoscience     Open Access   (Followers: 8)
Applied Network Science     Open Access   (Followers: 1)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Physics Research     Open Access   (Followers: 3)
Applied Sciences     Open Access   (Followers: 2)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 5)
Arabian Journal for Science and Engineering     Hybrid Journal   (Followers: 5)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4)
Archives of Foundry Engineering     Open Access  
Archives of Thermodynamics     Open Access   (Followers: 7)
Arkiv för Matematik     Hybrid Journal   (Followers: 1)
ASEE Prism     Full-text available via subscription   (Followers: 3)
Asia-Pacific Journal of Science and Technology     Open Access  
Asian Engineering Review     Open Access  
Asian Journal of Applied Science and Engineering     Open Access   (Followers: 1)
Asian Journal of Applied Sciences     Open Access   (Followers: 2)
Asian Journal of Biotechnology     Open Access   (Followers: 8)
Asian Journal of Control     Hybrid Journal  
Asian Journal of Current Engineering & Maths     Open Access  
Asian Journal of Technology Innovation     Hybrid Journal   (Followers: 8)
Assembly Automation     Hybrid Journal   (Followers: 2)
at - Automatisierungstechnik     Hybrid Journal   (Followers: 1)
ATZagenda     Hybrid Journal  
ATZextra worldwide     Hybrid Journal  
Australasian Physical & Engineering Sciences in Medicine     Hybrid Journal   (Followers: 1)
Australian Journal of Multi-Disciplinary Engineering     Full-text available via subscription   (Followers: 2)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 9)
Avances en Ciencias e Ingeniería     Open Access  
Balkan Region Conference on Engineering and Business Education     Open Access   (Followers: 1)
Bangladesh Journal of Scientific and Industrial Research     Open Access  
Basin Research     Hybrid Journal   (Followers: 5)
Batteries     Open Access   (Followers: 6)
Bautechnik     Hybrid Journal   (Followers: 1)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 23)
Beni-Suef University Journal of Basic and Applied Sciences     Open Access   (Followers: 4)
BER : Manufacturing Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Motor Trade Survey     Full-text available via subscription   (Followers: 1)
BER : Retail Sector Survey     Full-text available via subscription   (Followers: 2)
BER : Retail Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Survey of Business Conditions in Manufacturing : An Executive Summary     Full-text available via subscription   (Followers: 3)
BER : Survey of Business Conditions in Retail : An Executive Summary     Full-text available via subscription   (Followers: 4)
Bharatiya Vaigyanik evam Audyogik Anusandhan Patrika (BVAAP)     Open Access   (Followers: 1)
Biofuels Engineering     Open Access   (Followers: 1)
Biointerphases     Open Access   (Followers: 1)
Biomaterials Science     Full-text available via subscription   (Followers: 10)
Biomedical Engineering     Hybrid Journal   (Followers: 15)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 14)
Biomedical Engineering Letters     Hybrid Journal   (Followers: 5)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 18)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 34)
Biomedical Engineering: Applications, Basis and Communications     Hybrid Journal   (Followers: 5)
Biomedical Microdevices     Hybrid Journal   (Followers: 9)
Biomedical Science and Engineering     Open Access   (Followers: 4)
Biomedizinische Technik - Biomedical Engineering     Hybrid Journal  
Biomicrofluidics     Open Access   (Followers: 4)
BioNanoMaterials     Hybrid Journal   (Followers: 2)
Biotechnology Progress     Hybrid Journal   (Followers: 39)
Boletin Cientifico Tecnico INIMET     Open Access  
Botswana Journal of Technology     Full-text available via subscription   (Followers: 1)
Boundary Value Problems     Open Access   (Followers: 1)
Brazilian Journal of Science and Technology     Open Access   (Followers: 2)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 10)
Bulletin of Canadian Petroleum Geology     Full-text available via subscription   (Followers: 14)
Bulletin of Engineering Geology and the Environment     Hybrid Journal   (Followers: 14)
Bulletin of the Crimean Astrophysical Observatory     Hybrid Journal  
Cahiers, Droit, Sciences et Technologies     Open Access  
Calphad     Hybrid Journal  
Canadian Geotechnical Journal     Hybrid Journal   (Followers: 30)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 44)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 8)
Case Studies in Thermal Engineering     Open Access   (Followers: 4)
Catalysis Communications     Hybrid Journal   (Followers: 6)
Catalysis Letters     Hybrid Journal   (Followers: 2)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
Catalysis Science and Technology     Free   (Followers: 7)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysis Today     Hybrid Journal   (Followers: 7)
CEAS Space Journal     Hybrid Journal   (Followers: 1)
Cellular and Molecular Neurobiology     Hybrid Journal   (Followers: 3)
Central European Journal of Engineering     Hybrid Journal   (Followers: 1)
CFD Letters     Open Access   (Followers: 6)
Chaos : An Interdisciplinary Journal of Nonlinear Science     Hybrid Journal   (Followers: 2)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
Chinese Journal of Engineering     Open Access   (Followers: 2)
Chinese Science Bulletin     Open Access   (Followers: 1)
Ciencia e Ingenieria Neogranadina     Open Access  
Ciencia en su PC     Open Access   (Followers: 1)
Ciencias Holguin     Open Access   (Followers: 1)
CienciaUAT     Open Access  
Cientifica     Open Access  
CIRP Annals - Manufacturing Technology     Full-text available via subscription   (Followers: 11)
CIRP Journal of Manufacturing Science and Technology     Full-text available via subscription   (Followers: 14)
City, Culture and Society     Hybrid Journal   (Followers: 24)
Clay Minerals     Full-text available via subscription   (Followers: 10)
Clean Air Journal     Full-text available via subscription   (Followers: 2)
Coal Science and Technology     Full-text available via subscription   (Followers: 3)
Coastal Engineering     Hybrid Journal   (Followers: 11)
Coastal Engineering Journal     Hybrid Journal   (Followers: 5)
Coatings     Open Access   (Followers: 4)
Cogent Engineering     Open Access   (Followers: 2)
Cognitive Computation     Hybrid Journal   (Followers: 4)
Color Research & Application     Hybrid Journal   (Followers: 1)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 14)
Combustion, Explosion, and Shock Waves     Hybrid Journal   (Followers: 13)
Communications Engineer     Hybrid Journal   (Followers: 1)
Communications in Numerical Methods in Engineering     Hybrid Journal   (Followers: 2)
Components, Packaging and Manufacturing Technology, IEEE Transactions on     Hybrid Journal   (Followers: 27)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Composite Structures     Hybrid Journal   (Followers: 268)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 194)
Composites Part B : Engineering     Hybrid Journal   (Followers: 272)
Composites Science and Technology     Hybrid Journal   (Followers: 192)
Comptes Rendus Mécanique     Full-text available via subscription   (Followers: 2)
Computation     Open Access  
Computational Geosciences     Hybrid Journal   (Followers: 15)
Computational Optimization and Applications     Hybrid Journal   (Followers: 7)
Computational Science and Discovery     Full-text available via subscription   (Followers: 2)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 8)
Computer Science and Engineering     Open Access   (Followers: 19)
Computers & Geosciences     Hybrid Journal   (Followers: 29)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 6)
Computers and Electronics in Agriculture     Hybrid Journal   (Followers: 4)
Computers and Geotechnics     Hybrid Journal   (Followers: 11)
Computing and Visualization in Science     Hybrid Journal   (Followers: 6)
Computing in Science & Engineering     Full-text available via subscription   (Followers: 32)
Conciencia Tecnologica     Open Access  
Concurrent Engineering     Hybrid Journal   (Followers: 3)
Continuum Mechanics and Thermodynamics     Hybrid Journal   (Followers: 7)
Control and Dynamic Systems     Full-text available via subscription   (Followers: 9)
Control Engineering Practice     Hybrid Journal   (Followers: 43)
Control Theory and Informatics     Open Access   (Followers: 8)
Corrosion Science     Hybrid Journal   (Followers: 25)
Corrosion Series     Full-text available via subscription   (Followers: 6)
CT&F Ciencia, Tecnologia y Futuro     Open Access   (Followers: 1)

        1 2 3 4 5 6 7 | 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  [3118 journals]
  • Revised thermodynamic description of the Fe-Cr system based on an improved
           sublattice model of the σ phase
    • Abstract: Publication date: March 2018
      Source:Calphad, Volume 60
      Author(s): Aurélie Jacob, Erwin Povoden-Karadeniz, Ernst Kozeschnik
      The Fe-Cr system is re-assessed, focusing on an improved modeling of σ phase. The three sublattice model (Cr,Fe)10(Cr,Fe)4(Cr,Fe)16 is parameterized to model the σ phase, solving discrepancies between computed and experimental site fractions of previous descriptions. Taking into account relative metastability trends of end-member compounds from first-principles analysis, only two additional interaction parameters of the σ-FeCr description were required for the reproduction of the chemical structure, thermodynamic properties and phase boundaries.

      PubDate: 2017-12-27T12:27:34Z
  • A thermodynamic description of the U−Ti−Zr system
    • Abstract: Publication date: March 2018
      Source:Calphad, Volume 60
      Author(s): Yinping Zeng, Peng Zhou, Yong Du, Wenlin Mo, Bin Bai, Xiaolin Wang, Jingrui Zhao
      The U−Ti−Zr system was assessed by means of the CALPHAD method for the first time. Based on a critical evaluation of experimental phase diagram data available in the literature, a thermodynamic modeling was conducted for the individual phases. The solution phases including the liquid, hcp and bcc were described by a substitutional solution model. The binary compounds, U2Ti and UZr2, with a ternary extension were treated as one single phase using a sublattice model of (U,Zr)2/3(Ti,Zr)1/3. There is no ternary compound in this system. A set of self-consistent thermodynamic parameters for the U−Ti−Zr system was then obtained. Comparisons between the calculated and measured phase diagrams show that the experimental information is satisfactorily accounted for by the present thermodynamic description. The solvus projection and reaction scheme were generated using the present thermodynamic parameters. The presently calculated phase diagrams of U–Zr−Ti alloys can be used for further industrial application.

      PubDate: 2017-12-27T12:27:34Z
  • Interdiffusion and atomic mobility in bcc Ti–rich
           Ti–Nb–Zr system
    • Abstract: Publication date: March 2018
      Source:Calphad, Volume 60
      Author(s): Weimin Chen
      Accurate interdiffusion information is the necessity for the control of the production of homogeneous biomedical alloys. Ternary interdiffusivities in bcc Ti–rich Ti–Nb–Zr alloys at 1273K were determined by using the combination of the diffusion couple technique and the Matano–Kirkaldy method. Subsequently, on the basis of the presently obtained interdiffusivities together with the diffusivity and mobility parameters of sub–binary Ti–Nb–Zr system and the thermodynamic descriptions for bcc Ti–Nb–Zr system, the atomic mobilities of Ti, Nb and Zr in bcc Ti–Nb–Zr alloys were assessed by means of DICTRA (DIffusion Controlled TRAnsformation) software package. Moreover, the comprehensive comparisons between the experimental diffusion properties (i.e., interdiffusivities, composition profiles, interdiffusion fluxes and diffusion paths) and the calculated/model–predicted data due to the present atomic mobilities were conducted in order to verify the reliability of the mobilities. The present atomic mobilities for bcc Ti–Nb–Zr system can provide the accurate interdiffusivity matrix over the wide composition range.

      PubDate: 2017-12-27T12:27:34Z
  • Composition-dependent interdiffusivity matrices in face centered cubic
           Ni–Al–X (X = Rh and W) alloys at 1423, 1473 and 1523K: A
           high-throughput experimental measurement
    • Abstract: Publication date: March 2018
      Source:Calphad, Volume 60
      Author(s): Juan Chen, Lijun Zhang
      Based on 18 face centered cubic (fcc) single-phase diffusion couples in ternary Ni–Al–X (X = Rh and W) systems together with the recently developed numerical inverse method, high-throughput measurements of the composition-dependent interdiffusivity matrices in fcc Ni–Al–X (X = Rh and W) alloys at 1423, 1473 and 1523K were performed in the present work. Their reliability was comprehensively validated through comparison between the model-predicted composition/interdiffusion flux profiles for each diffusion couple and the corresponding experimental data. Moreover, the direct comparison with the interdiffusivities evaluated from traditional Matano-Kirkaldy method as well as those from the literature and in the boundary binary systems was also made. The errors for the determined interdiffusivities were evaluated by a scientific method considering the error propagation. The three-dimensional main interdiffusivity planes for fcc Ni–Al–X (X = Rh and W) systems over the investigated concentration ranges at 1423, 1473 and 1523K were subsequently constructed. It was then found that D ˜ A l A l N i is generally larger than D ˜ R h R h N i , while D ˜ W W N i is the smallest.

      PubDate: 2017-12-27T12:27:34Z
  • Phase equilibria studies of CaO-SiO2-Al2O3-Fe2O3-MgO system using CALPHAD
    • Abstract: Publication date: March 2018
      Source:Calphad, Volume 60
      Author(s): Tazuddin, Hemantkumar N. Aiyer, Amit Chatterjee
      A detailed CALPHAD (CALculation of PHAse Diagram) based thermodynamic study on CaO- SiO2-Al2O3-Fe2O3-MgO system (C-A-S-F-M) has been carried out to study the evolution of phases during heating and to investigate the effects of individual oxides. The important phases present at high temperature in the system are tricalcium silicate (C3S), dicalcium silicate (C2S), tricalcium aluminate (C3A), dicalcium ferrite (C2F) and a liquid phase. The evolution of liquid phase and other important phases predicted by CALPHAD closely matches with the experimental results. It was observed that in C-A-S-F-M system, there is a critical percentage of CaO and SiO2 at which C3S is maximum. Both Fe2O3 and Al2O3 significantly increase the amount of liquid phase. Both Fe2O3 and Al2O3 reduce C3S and increase C2S in the system. Up to 1.5wt%, MgO also helps in increasing liquid phase. A mathematical model to predict phases has been developed as an alternative to the Bougue's equation which is very effective in predicting phase fractions.

      PubDate: 2017-12-27T12:27:34Z
  • Thermodynamic assessment of binary erythritol-xylitol phase diagram for
           phase change materials design
    • Abstract: Publication date: March 2018
      Source:Calphad, Volume 60
      Author(s): Saman Nimali Gunasekara, Huahai Mao, Sedigheh Bigdeli, Justin NingWei Chiu, Viktoria Martin
      Here, the erythritol-xylitol binary system was thermodynamically optimized based on available experimental phase equilibrium data, to explore compositions suitable as phase change materials (PCMs) for thermal energy storage (TES). A previous experimental study revealed that erythritol-xylitol was a partially isomorphous system with a eutectic. In the thermodynamic evaluation, the CALPHAD method was employed coupling the phase diagram and thermodynamic property information. There, both unary and binary systems’ experimental data were taken into account, and all phases were described using the substitutional solution model. Finally, a self-consistent thermodynamic description for the erythritol-xylitol system was achieved. The calculated eutectic point is at 76.7°C and 26.8mol% erythritol, agreeing well with the experimental data. The calculated phase diagram better-verifies the systems’ solidus and the solvus, disclosing the stable phase relations. Based on the Gibbs energy minimization, phase diagrams can be predicted for the binary and higher order systems, provided the component subsystems are thermodynamically assessed beforehand. In conclusion, to move forward beyond e.g. non-isomorphous simple eutectic systems, methods using Gibbs free energy minimization from a fundamental point-of-view such as CALPHAD are essential.

      PubDate: 2017-12-13T09:33:36Z
  • Thermodynamics of liquid Sn-Pb alloys determined by vapour pressure
    • Abstract: Publication date: March 2018
      Source:Calphad, Volume 60
      Author(s): Andrzej Zajączkowski
      Application of Knudsen method in the studies of liquid Sn-Pb alloys, containing from 4.85 to 95.31mol% of lead, in temperatures from 851 to 1186K, and liquid tin and lead, in temperatures 1360 – 1442 and 934 – 1149K, respectively, provided experimental data which made characterization of thermodynamic properties of liquid phase of Sn-Pb system possible. Parameters of the Redlich-Kister equation, describing excess Gibbs energy of liquid phase of the examined system, were determined. With application of the third law method standard enthalpies of sublimation of tin and lead were calculated.

      PubDate: 2017-12-13T09:33:36Z
  • Assessment of the Al-Bi-Mg system and extrapolation to the Al-Bi-Mg-Sn
           quaternary system
    • Abstract: Publication date: March 2018
      Source:Calphad, Volume 60
      Author(s): Chunju Niu, Changrong Li
      The phase equilibria in the Al-Bi-Mg-Sn quaternary system have been studied using the CALPHAD (CALculation of PHAse Diagram) method. One of the four ternary systems constituting the quarternary system, the Al-Bi-Mg system, is re-assessed by means of the CALPHAD technique and Thermo-Calc software package, in consideration of the associate model for the liquid phase instead of the Modified Quasi-chemical Model used in the literature report. While for the other three ternary systems, the Al-Bi-Sn, the Al-Mg-Sn and the Bi-Mg-Sn systems, the thermodynamic parameters are mainly adopted from the literature reported optimization results with a little modification to the Al-Bi-Sn and the Al-Mg-Sn systems for the compatibility of all the constituent binary systems. The assessment results of the Al-Bi-Mg ternary system are in good agreement with the available experimental phase relations, including the liquidus surface projection and the vertical sections. The thermodynamic database of the Al-Bi-Mg-Sn quaternary system was developed without the consideration of the quaternary interactions and the quaternary compounds. With this newly developed thermodynamic database, the phase equilibria and the solidification processes of the ternary and the quarternary systems are calculated and analyzed.

      PubDate: 2017-12-13T09:33:36Z
  • Experimental investigation and simulation of precipitation evolution in
           Mg-3Nd-0.2Zn alloy
    • Abstract: Publication date: March 2018
      Source:Calphad, Volume 60
      Author(s): Xiangyu Xia, Amirreza Sanaty-Zadeh, Chuan Zhang, Alan A. Luo, Donald S. Stone
      In this research, precipitation evolution and strengthening behavior in Mg-3Nd-0.2Zn alloy during isothermal age treatment at 200°C are quantitatively studied by a combination of experimental investigation and computational simulation. Microstructure evolution, including volume fraction, number density, and size of precipitates are first measured by TEM and DSC techniques and then modeled using an integrated computational simulation method combining the CALPHAD (CALculation of PHAse Diagram) approach and classical nucleation model. The focus of the analysis is set on the evolution of key strengthening precipitate β’. Critical kinetic parameters such as particle interfacial energy and nucleation site number are obtained computationally by fitting the model to the experimental data. Mechanical properties of a series of Mg-Nd-Zn alloys are predicted using the simulated microstructure evolution as inputs. Good agreement is found between simulated and measured results. Strategies for enhancing the precipitation hardening effect are presented and discussed based on the simulation results. The merit of this study is to use the obtained parameters to extrapolate microstructure evolution and mechanical properties when adjusting alloy composition and/or heat treatment conditions within a certain range, which will be very useful for further development and optimization of multi-component Mg alloys.

      PubDate: 2017-12-13T09:33:36Z
  • Genetic programming based models for prediction of vapor-liquid
    • Abstract: Publication date: March 2018
      Source:Calphad, Volume 60
      Author(s): Veena Patil-Shinde, Sanjeev S. Tambe
      The design, operation, and control of chemical separation processes heavily rely on the knowledge of the vapor-liquid equilibrium (VLE). Often, conducting experiments to gain an insight into the separation behavior becomes tedious and expensive. Thus, standard thermodynamic models are used in the VLE prediction. Sometimes, exclusively data-driven models are also used in VLE prediction although this method too possesses drawbacks such as a trial and error approach in specifying the data-fitting function. For overcoming these difficulties, this paper employs a machine learning (ML) formalism namely “genetic programming (GP)” possessing certain attractive features for the VLE prediction. Specifically, three case studies have been performed wherein GP-based models have been developed using experimental data, for predicting the vapor phase composition of a ternary, and a group of non–ideal binary systems. The inputs to models consists of three pure component attributes (acentric factor, critical temperature, and critical pressure), and as many intensive thermodynamic parameters (liquid phase composition, pressure, and temperature). A comparison of the VLE prediction and generalization performance of the GP-based models with the corresponding standard thermodynamic models reveals that the former class of models possess either superior or closely comparable performance vis-a-vis thermodynamic models. Noteworthy features of this study are: (i) a single GP-based model can predict VLE of a group of binary systems, and (ii) applicability of a GP-based model trained on an alcohol-acetate series data for its higher homolog. The VLE modeling approach exemplified here can be gainfully extended to other ternary and non-ideal binary systems, and for designing corresponding experiments in different pressure and temperature ranges.

      PubDate: 2017-12-13T09:33:36Z
  • Experimental reinvestigation and thermodynamic description of Bi-Te binary
    • Abstract: Publication date: March 2018
      Source:Calphad, Volume 60
      Author(s): Cun Mao, Mingyue Tan, Ligang Zhang, Di Wu, Weiming Bai, Libin Liu
      The Bi-Te phase diagram was determined by equilibrium alloy method, combined with electron probe microanalysis (EPMA), X-ray diffraction (XRD) and thermal analysis (DSC). The experimental result shows that there is a β-phase with a large composition range at low temperature, while Bi2Te and Bi4Te3 are relatively stable in the solid-liquid region. A consistent phase diagram that covers the experimental findings has been achieved. Based on the new experimental phase diagram, coupling with the reported thermodynamic data, the thermodynamic optimization of the Bi-Te binary system was carried out with the help of CALPHAD approach. A group of reasonable thermodynamic parameters was obtained.

      PubDate: 2017-12-13T09:33:36Z
  • Reconciling SGTE and ab initio enthalpies of the elements
    • Abstract: Publication date: March 2018
      Source:Calphad, Volume 60
      Author(s): Axel van de Walle
      The CALPHAD framework is built on assumption that all phases have a well-defined free energy over all accessible composition, temperature and pressure conditions. Unfortunately, it is common for phases to exhibit mechanical instabilities in at least some range of conditions, thus precluding direct experimental measurements and hindering computational efforts. A pragmatic solution has often been to extrapolate free energies from stable region into the unstable regions, but extrapolations from different systems that share a common phase may not agree and extrapolated free energies can unintentionally lie below the free energy of stable phases. Computational approaches that aim to directly calculate the free energy of unstable phases offer a promising avenue to address these issues. Among them, the recently proposed “inflection detection” scheme lies on a strong theoretical footing. We provide further support for this approach by demonstrating that it yield free energies that agree very well with the widely used SGTE (Scientific Group Thermodata Europe) data for pure elements. This finding suggest that it may be possible to get the best of both worlds: obtain a theoretically justified definition of the free energy of mechanically unstable phases and preserve much of existing empirical standards for the assignments of such free energies.
      Graphical abstract image Highlights fx1

      PubDate: 2017-11-16T10:46:39Z
  • Density functional study of the thermodynamic properties and phase diagram
           of the magnesium hydride
    • Abstract: Publication date: March 2018
      Source:Calphad, Volume 60
      Author(s): Hasan S. AlMatrouk, Viorel Chihaia, Valentin Alexiev
      This paper focuses primarily on the P-T phase diagram determination by considering six polymorphs of magnesium hydride (α - rutile TiO2, P4 2 /mnm, β - cubic modified CaF2, Pa 3 ¯ , γ - orthorhombic PbO2, Pbcn, δ' - orthorhombic, Pbca and cubic - Fm 3 ¯ m). The Gibbs free energy and other thermodynamic properties were evaluated by DFT-based thermodynamic calculations, within the frame of the quasi-harmonic approximation, for the pressure range 0–10GPa and temperatures between 0 and 1200K. Furthermore, the structural, energetic, and electronic properties of the investigated structures are conversed.

      PubDate: 2017-11-16T10:46:39Z
  • Thermodynamic modeling of the V-Si-B system
    • Abstract: Publication date: December 2017
      Source:Calphad, Volume 59
      Author(s): Antonio Augusto Araujo Pinto da Silva, Nabil Chaia, Flavio Ferreira, Gilberto Carvalho Coelho, Jean-Marc Fiorani, Nicolas David, Michel Vilasi, Carlos Angelo Nunes
      In the present work, the V-Si-B ternary system was thermodynamically modeled using the CALPHAD method. The thermodynamic descriptions of the V-Si and B-Si binary systems were taken from literature while the parameters of binary V-B were re-evaluated, based on new experimental information. The ternary thermodynamic description was based on experimental data of isothermal section and liquidus projection. The binary compounds V3B2, VB, V5B6, V3B4, V2B3 and VB2 were modeled as stoichiometric phases; the terminal solid solutions BCC and β-Rhomb were modeled using the sublattice models (V,Si)1(B,va)3 and (B)93(B, Si)12; the ternary phases D88 and T2 were modeled as (V)0.5556(B,Si)0.3333(B,va)0.1111 and (V)0.625(B,Si)0.375, respectively. A set of thermodynamic parameters is proposed and the results showed a good agreement with available experimental information from the literature.

      PubDate: 2017-11-09T09:20:00Z
  • First-principles calculations and thermodynamic modeling of the Yb-Ni
           binary system
    • Abstract: Publication date: December 2017
      Source:Calphad, Volume 59
      Author(s): Yong-Jie Hu, Yi Wang, Samad A. Firdosy, Kurt E. Star, Jean-Pierre Fleurial, Vilupanur A. Ravi, Zi-Kui Liu
      A complete thermodynamic description of the Yb-Ni binary system is developed by means of the CALculation of PHAse Diagram (CALPHAD) method in combination with first-principles calculations based on density functional theory (DFT) and available experimental data in the literature. Finite temperature thermodynamic properties of the Yb-Ni intermetallic compounds are predicted using the quasi-harmonic approach, where first-principles phonon calculations are performed to calculate the lattice vibrational entropy. The associate solution model is used to describe the complex thermodynamic behavior of the liquid phase. The calculated phase diagram agrees well the experimental phase equilibrium data in the literature. By the coupling of CALPHAD modeling with first-principles calculations, the present work provides a more thermodynamically accurate model of the Yb-Ni system when compared to previous models.

      PubDate: 2017-11-09T09:20:00Z
  • Thermodynamic re-assessment of the Fe-Dy and Fe-Tb binary systems
    • Abstract: Publication date: December 2017
      Source:Calphad, Volume 59
      Author(s): M.H. Rong, X.L. Chen, J. Wang, G.H. Rao, H.Y. Zhou
      In this work, based on the critical evaluation of previous optimizations and available experimental data in the published literature, the Fe-Dy and Fe-Tb binary systems were re-assessed thermodynamically using the CALPHAD method. The solution phases including liquid, fcc-Fe, bcc-Fe, bcc-Dy, bcc-Tb, hcp-Dy and hcp-Tb, were described by the substitutional solution model and their excess Gibbs energies were expressed with the Redlich-Kister polynomial. Due to their narrow homogeneity ranges, the intermetallic compounds, Fe17Dy2, Fe23Dy6, Fe3Dy, Fe2Dy, Fe17Tb2, Fe23Tb6, Fe3Tb and Fe2Tb, were modeled as stoichiometric compounds. Self-consistent thermodynamic parameters to describe the Gibbs energies of various phases in the Fe-Dy and Fe-Tb binary systems were obtained finally. The calculated results are in good agreement with the reported phase equilibria and thermodynamic properties.

      PubDate: 2017-11-02T09:09:19Z
  • Numerical modelling of moving interfaces under local equilibrium
    • Abstract: Publication date: December 2017
      Source:Calphad, Volume 59
      Author(s): Jae Sang Lee, Dong-Woo Suh, Yang Mo Koo, Seong Gyoon Kim
      A new method is presented to simulate moving interfaces during diffusion-controlled growth under local equilibrium conditions. The position and compositions of the interface are obtained directly from the equilibrium state of the subsystem around the moving interface, without iterative calculation between diffusion fluxes and solute balance conditions. The method is applicable to general multi-component systems, and it ensures the consistency in compositions and solute balance at the interfaces; Those are ascribed to the presented consideration of subsystem around the interface region in a discretized form. Explicit equations of interface compositions and position in discretized variables are also presented for the simplified ternary systems of two-solution and compound/solution. The validity and usefulness of the method is demonstrated by simulations of the two important ternary systems; The simulation results illustrate the features of diffusion-controlled growth with different alloy compositions and diffusivities of solutes in both systems.
      Graphical abstract image

      PubDate: 2017-11-02T09:09:19Z
  • Thermodynamic modeling of phase equilibria and defect chemistry in the
           Zn-S system
    • Abstract: Publication date: December 2017
      Source:Calphad, Volume 59
      Author(s): Pin-Wen Guan, Shun-Li Shang, Greta Lindwall, Tim Anderson, Zi-Kui Liu
      Though important and fundamental, a satisfactory theoretical framework of modeling multiple point defects in the context of phase equilibria is still lacking. In this work, a methodology that models point defects, electrons, holes and the underlying phase equilibria simultaneously is developed and applied to the Zn-S system. It overcomes some issues in previous works, such as inconsistency in the reference state for electrons. The model parameters are directly related to the Gibbs energy of formation of point defects computed from first-principles phonon calculations. A double exponential function is proposed to parameterize the entropy of formation of point defects as a function of temperature. Using this approach, phase diagrams, concentrations of point defects and free carriers, the majority carrier, and defect-related properties exemplified by the electrical conductivity are obtained under various conditions, in agreement with experimental data. The present methodology provides a way to integrate first-principles calculations and experimental data into the CALPHAD model, enabling description of multi-component semiconductor systems.

      PubDate: 2017-11-02T09:09:19Z
  • Phase relations in the Cu-O-Al2O3-SiO2 system at 1150°C and
           1300°C in air
    • Abstract: Publication date: December 2017
      Source:Calphad, Volume 59
      Author(s): Niko Hellstén, Pekka Taskinen
      Phase equilibria of the Cu-O-Al2O3-SiO2 system are important in the processing of copper aluminosilicate glasses, mullite ceramics and in non-ferrous metallurgy. We experimentally investigated the phase equilibria of this system at 1150°C and 1300°C in air atmosphere using equilibration and quenching method. Chemical compositions of the liquid and solid phases in the quenched samples were determined by Electron Probe Microanalysis (EPMA). Based on the results, we constructed an isothermal section containing the liquidus contours of various primary phases at 1300°C. Comparison of these results with previous experimental work confirms that oxygen pressure affects phase stability and composition of the liquidus in this system. The experimental liquidus determined in this work disagrees by up to 50wt% with the calculated values of MTDATA 6.0 software and Mtox database version 8.2. Concentration of ‘Cu2O′ in mullite ranged from 0.46wt% to 1.25wt%. The results of this work will enable improvement of thermodynamic descriptions for this system.

      PubDate: 2017-11-02T09:09:19Z
  • Experimental investigation and thermodynamic calculation of the B-Fe-Mo
           ternary system
    • Abstract: Publication date: December 2017
      Source:Calphad, Volume 59
      Author(s): Xuemei Ou Yang, Fucheng Yin, Jingxian Hu, Manxiu Zhao, Ye Liu
      The phase relationship of the B-Fe-Mo ternary system has been investigated combining experimental results with thermodynamic modeling. The liquidus projection of the ternary system in the Fe-rich region was constructed by identifying primary crystallization phases in the as-cast alloys and determining liquid temperatures obtained from the DSC analyses. Eight different primary solidification regions were observed, and they are BCC, FCC, Mo2FeB2, Fe2B, FeB, σ, and R, respectively. And four invariant reactions were identified in the Fe-rich region. Thermodynamic optimization of the B-Fe-Mo ternary system was performed using CALPHAD approach based on the thermodynamic models of the three constitutional binary systems and the experimental results of the ternary system. A set of self-consistent thermodynamic parameters for the B-Fe-Mo system were obtained with reasonable agreement between the experimental and calculated results.

      PubDate: 2017-11-02T09:09:19Z
  • CALPHAD modeling of metastable phases and ternary compounds in Ti-Al-N
    • Abstract: Publication date: December 2017
      Source:Calphad, Volume 59
      Author(s): Yanhui Zhang, Peter Franke, Hans Jürgen Seifert
      The development and evaluation of thermodynamic databases for the Ti-Al-N system is important for a wide range of engineering alloys. In this work, we resorted to the integration of ab initio thermodynamics, experiments and CALPHAD modeling for a comprehensive understanding of the metastable and the ternary phases in Ti-Al-N system. The supersaturated solutions of (Ti,Al)N with both rocksalt and wurtzite structures were well described by using the sub-regular solution model. Thereby, the formation, the phase separation and the meta-solubility of TiAlN coatings were successfully elaborated by the metastable pseudo-binary TiN-AlN section and the PVD (physical vapor deposition) phase diagram. Moreover, a number of isothermal and isopleth sections were also calculated and compared with available experiments and previous thermodynamic assessments. For the first time the ternary compound of τ 3 was corrected as Ti 4 AlN 3 in our proposed database.

      PubDate: 2017-10-14T14:28:02Z
  • Thermodynamic re-assessment of the Al-Co-W system
    • Abstract: Publication date: December 2017
      Source:Calphad, Volume 59
      Author(s): Peisheng Wang, Wei Xiong, Ursula R. Kattner, Carelyn E. Campbell, Eric A. Lass, Oleg Y. Kontsevoi, Gregory B. Olson
      The Al-Co-W system and its binary sub-systems Al-Co, Al-W and Co-W were critically reviewed. The thermodynamic description of the Al-Co-W system including all three binaries was developed considering thermodynamic and constitutional data of the systems. Results from density functional theory calculations were employed to improve reliability of the descriptions. The Gibbs energy for the thermal vacancy (GVa) in the BCC_A2 phase is discussed. The revised descriptions obtained for the Al-W and Co-W systems describe the thermodynamic and phase equilibrium data well and are free of undesired artefacts for temperatures below 6000K. The ordered γ’ phase of the Al-Co-W system is described as a metastable phase in the entire temperature range. The calculated Gibbs energy of the γ’ is only slightly above that of the equilibrium state, which indicates that there is good possibility of stabilizing the γ’ phase with the addition of γ’-stabilizing elements, such as Ti, Ta, Hf, Nb and Ni.

      PubDate: 2017-10-11T14:13:11Z
  • Second nearest-neighbor modified embedded-atom method interatomic
           potentials for the Pt-M (M = Al, Co, Cu, Mo, Ni, Ti, V) binary systems
    • Abstract: Publication date: December 2017
      Source:Calphad, Volume 59
      Author(s): Jin-Soo Kim, Donghyuk Seol, Joonho Ji, Hyo-Sun Jang, Yongmin Kim, Byeong-Joo Lee
      Interatomic potentials for Pt-M (M = Al, Co, Cu, Mo, Ni, Ti, V) binary systems have been developed on the basis of the second nearest-neighbor modified embedded-atom method (2NN MEAM) formalism. The parameters of pure Mo have also been newly developed to solve a problem in the previous 2NN MEAM potential in which the sigma and α-Mn structures become more stable than the bcc structure. The potentials reproduce various materials properties of alloys (structural, thermodynamic and order-disorder transition temperature) in reasonable agreements with relevant experimental data and other calculations. The applicability of the developed potentials to atomistic investigations for the shape and atomic configuration of Pt bimetallic nanoparticles is demonstrated.

      PubDate: 2017-10-11T14:13:11Z
  • A new thermodynamic description of stable Cr-carbides for the third
           generation of thermodynamic database
    • Abstract: Publication date: December 2017
      Source:Calphad, Volume 59
      Author(s): Zhou Li, Huahai Mao, Malin Selleby
      An updated thermodynamic description of the stable Cr-carbides was obtained by applying the same models as used for the elements within the 3rd generation of thermodynamic databases. The Einstein model was used and a scaling factor was introduced to take into account the coupling effect between the stoichiometry (C to Cr ratio) and the structure of the compound. Using this model we could accurately describe the thermodynamic properties of these stoichiometric compounds using available experimental heat capacity data. The new description is now more physically sound and results in a better agreement with the experimental heat capacity data.

      PubDate: 2017-10-03T13:00:11Z
  • Thermodynamic modeling of the Ta–Mo–C ternary system
    • Abstract: Publication date: December 2017
      Source:Calphad, Volume 59
      Author(s): Cong Zhang, Haiqing Yin, Yong Du, Yafei Pan, Peng Deng
      The Ta–Mo–C system was assessed by means of the CALPHAD approach. All of the phase diagram and thermodynamic information available from the literature were critically reviewed. The liquid was modeled as substitutional solution phase, while the carbides including fcc-(Mo,Ta)C1-x , bcc-(Mo,Ta), hcp-(Mo,Ta)2C and η-MoC were described by using corresponding sublattice models. The ζ-Ta4C3-x was considered as a linear compound with carbon content fixed, while shp-MoC was treated to be a binary stoichiometric phase. There was no ternary compound reported in this system. The modeling of Ta–Mo–C ternary system covers the entire composition and temperature ranges, and a set of self-consistent thermodynamic parameters for the Ta–Mo–C system was systematically optimized. Comprehensive comparisons between the calculated and reported phase diagram and thermodynamic data show that the reliable information is satisfactorily accounted for by the present modeling. The liquidus projection and reaction scheme of the Ta–Mo–C system were also generated by using the present thermodynamic parameters.

      PubDate: 2017-09-26T12:20:07Z
  • Thermodynamic modeling of the Ca(NO3)2-MNO3 (M: alkali metal) systems
    • Abstract: Publication date: December 2017
      Source:Calphad, Volume 59
      Author(s): Xiang Li, Kun Wang, Miao Shen, Zhu Wu, Leidong Xie
      This work presents a thermodynamic evaluation of the Ca(NO3)2-MNO3 (M: Li, Na, K, Rb, Cs) binary systems using the CALPHAD approach. The required Gibbs energy of liquid Ca(NO3)2 is missing in the literature and has been successfully evaluated in the present work with a fusion enthalpy of 23849Jmol−1. The substitutional solution model can thus be employed to describe the Ca(NO3)2-base liquid phase. All the intermediate compounds are treated to be stoichiometric and their Gibbs energies comply with the Neumann-Kopp rule. Empirical functions relating mixing enthalpies to ionic parameters are employed to predict the corresponding values of binary melts which are used as input data to assist in parameters optimization for the liquid phases. The final calculated results show good agreement with most of the experimental and predicted data.

      PubDate: 2017-09-19T14:40:54Z
  • Diffusivities and atomic mobilities for fcc Cu–Ni–Sn alloys
    • Abstract: Publication date: December 2017
      Source:Calphad, Volume 59
      Author(s): Yuling Liu, Chong Chen, Dandan Liu, Yong Du, Shuhong Liu, Xiaoma Tao, Yifang Ouyang
      Utilizing five groups of bulk diffusion couples together with electron probe microanalysis technique, the composition-dependent ternary interdiffusion coefficients in fcc Cu–Ni–Sn alloys at 1023K were determined via the Whittle and Green method. The presently obtained interdiffusion coefficients at 1023K as well as our previously measured ones at 1073K were combined with the slightly modified thermodynamic descriptions of the fcc Cu–Ni–Sn phase to explore atomic mobilities of Cu, Ni and Sn in fcc Cu–Ni–Sn alloys within the CALPHAD framework. In order to be consistent with the thermodynamic description, atomic mobilities in binary fcc Ni–Sn alloys were re-evaluated in the present work. The quality of the assessed kinetic characteristics was confirmed by the comprehensive comparisons between various model-predicted diffusion behaviors and the experimental ones, including concentration profiles and diffusion paths.

      PubDate: 2017-09-14T08:18:29Z
  • Ab initio-assisted assessment of the CaO-SiO2 system under pressure
    • Abstract: Publication date: December 2017
      Source:Calphad, Volume 59
      Author(s): D. Belmonte, G. Ottonello, M. Vetuschi Zuccolini
      We present the results of an ab initio-assisted assessment of melting and subsolidus phase relations in the system CaO-SiO2 up to high pressure conditions. All solid compounds known to nucleate in the system have been treated as purely stoichiometric and the liquid resolved in the framework of a simple polymeric model. Mixing properties of the binary liquid phase are fully described by a single-parameter purely enthalpic chemical interaction plus a strain energy contribution. The latter is required to predict liquid immiscibility of SiO2-rich liquid compositions at ambient conditions and becomes irrelevant at P>2GPa. A detailed survey of thermodynamic properties of silica polymorphs and calcium oxide and silicates in a broad range of P-T conditions reveals quite controversial stability relations and melting behavior. First-principles calculations on CaO and SiO2 pure liquid components and solid phases (lime and stishovite) have been used, along with a sound assessment of first- and second-order phase transitions, to reconcile thermochemical data with topological details of the observed phase diagrams. A physically-consistent coupling between thermodynamic and thermoelastic properties (viz. compressibility and thermal expansion) turns out to be of fundamental importance to infer reliable stability relations both at subsolidus and melting conditions. Pressure effects shift the composition of the main invariant points in the CaO-SiO2 system and also change the melting behavior of the CaSiO3 metasilicate in a complex manner.

      PubDate: 2017-09-02T07:41:30Z
  • Phase equilibria in the ternary Fe-Co-S system
    • Abstract: Publication date: December 2017
      Source:Calphad, Volume 59
      Author(s): Mariia O. Ilatovskaia, Svetlana I. Sinyova, Roman V. Starykh
      The Fe-FeS-CoS-Co system has been investigated experimentally from 1073K up to liquidus temperature. Samples of the system have been investigated using DTA/TGA, SEM/EDX, and XRD methods. Liquidus and solidus projections have been plotted based on experimental data.

      PubDate: 2017-09-02T07:41:30Z
  • Vapor pressure of alkali-metal binary alloys in glass cells
    • Abstract: Publication date: December 2017
      Source:Calphad, Volume 59
      Author(s): Kiyoshi Ishikawa
      The alkali partial pressures of composite alkali-metal vapor are crucial in atomic-physics optical experiments. The vapor pressures of alkali-metal binary alloys can be calculated by using the activity and the mixing enthalpy for homogeneous alloys from early measurements. We show that the results of sodium-containing alloys deviate appreciably from the prediction of Raoult's law. Experimentally, the phase and the mixing ratio of binary alloys are non-destructively measured by nuclear-magnetic-resonance spectroscopy in glass cells. We find that many droplets of the sodium-rubidium alloy exist on the cell walls, and they have different mixing ratios. Therefore, the vapor density varies microscopically around the glass cells. To achieve precision optical measurements, we should take account of the pressure change due to the equilibrium process and further sodium contamination over the lifetime of glass cells.

      PubDate: 2017-09-02T07:41:30Z
  • The reassessment of the Al-V system and new assessment of the Al-Si-V
    • Abstract: Publication date: December 2017
      Source:Calphad, Volume 59
      Author(s): A. Kroupa, M. Mazalová, K.W. Richter
      The theoretical assessment of the Al-Si-V system has been carried out and has been presented here. The experimental results from Huber et al. [1,2] were used as the basis of the assessment. The relevant binary system assessments for Al-V [9], Al-Si [13] and Si-V [14] were used in the initial stage of the study and it was found that complete reassessment of the Al-V system was necessary. The reassessed dataset for the Al-V system is in very good agreement not only with existing experimental phase diagram and thermodynamic data, but is also consistent with the independent work of Lindahl et al. [22]. The final assessment of the Al-Si-V system using our own reassessed Al-V system is in excellent agreement with the experimental data.

      PubDate: 2017-09-02T07:41:30Z
  • Thermodynamic reassessment of the novel solid-state thermal energy storage
           materials: Ternary polyalcohol and amine system
    • Abstract: Publication date: December 2017
      Source:Calphad, Volume 59
      Author(s): Renhai Shi, Dhanesh Chandra, Amrita Mishra, Anjali Talekar, Muralidhar Tirumala, Daryl J. Nelson
      Organic polyalcohol and amine globular molecular crystals such as PG, TRIS, and NPG are considered as the most promising potential candidates for solid-state thermal energy storage in the orientationally disordered high temperature phases. In this study, we first propose a new PG-TRIS-NPG phase diagram based on experimental data of the three sub-binary systems NPG-PG, PG-TRIS, and NPG-TRIS with CALPHAD methodology. The NPG-PG binary phase diagram was optimized using sub-regular models that showed complete miscibility in the entire compositional range of high temperature γ′ (FCC) phase region, and an invariant equilibrium point at 299.5K. The NPG-TRIS binary system was also calculated using sub-regular model, from sub-ambient to well above the melting temperatures, and determined three invariant equilibria at 311.1K, 391.8K, and 410.6K, respectively. These calculated binary phase diagrams are in good agreement with the experimental data. The PG-TRIS-NPG ternary system has also been calculated and qualitatively analyzed using the CALPHAD method and Thermo-Calc software. A set of self-consistent thermodynamic parameters formulating the Gibbs energies of various phase in the PG-TIRS-NPG ternary system are obtained in the present work. Thermodynamic properties such as several isotherms, isopleths, and liquidus projections are calculated by using present datasets as shown in this work in which the solid ternary compound (TRIS0.5NPG0.5)XPG1−X (0.1≤x≤0.9), (TRIS0.5PG0.5)XNPG1−X (0.1≤x≤0.9), and (PG0.5NPG0.5)XTRIS1−X (0.1≤x≤0.9) with various solid-solid phase transitions at different temperatures could apply to applications in the solid-state thermal energy storage.

      PubDate: 2017-09-02T07:41:30Z
  • A method of integrating CALPHAD data into phase-field models using an
           approximated minimiser applied to intermetallic layer growth in the Al-Mg
    • Abstract: Publication date: December 2017
      Source:Calphad, Volume 59
      Author(s): M.J. Welland, M.H.A. Piro, S. Hibbins, N. Wang
      This article describes an approach to combine single phase thermodynamic potentials into a multiphase composite potential suitable for integration in a multicomponent phase-field model. The composite potential avoids implicit interfacial energy contributions by starting from a grand potential formulation. The method is made explicit by expanding the minimiser resulting from the Legendre transform between grand and Helmholtz potentials about a known equilibrium state. The resulting composite function is explicit, reproduces the equilibrium states exactly, and is smooth such that it can be differentiated to provide the driving forces for mass transport and phase change in a thermodynamically self-consistent manner. The model is demonstrated by simulating a sequence of phase transformations for intermetallic growth in Al-Mg interdiffusion for advanced nuclear research reactor fuel.

      PubDate: 2017-09-02T07:41:30Z
  • Critical assessment and thermodynamic modeling of the
           Cu–Fe–O–Si system
    • Abstract: Publication date: September 2017
      Source:Calphad, Volume 58
      Author(s): Taufiq Hidayat, Denis Shishin, Sergei A. Decterov, Evgueni Jak
      The present study is the first Calphad-type assessment of the Cu–Fe–O–Si system. All relevant thermodynamic and phase equilibrium data have been critically evaluated to produce a thermodynamic database describing the Gibbs energies of all phases in the system. The predictive range of the database covers all conditions of pyrometallurgical production of copper in terms of temperature and oxygen partial pressure. Liquid oxide slag and liquid metal phases have been described using two separate solution models, both developed within the framework of the Modified Quasichemical Formalism. Slag model is expressed as [Cu+, Fe2+, Fe3+, Si4+][O2-] and metal model is expressed as (CuI, FeII, OII). They are internally consistent with the models for fcc–Cu, fcc–Fe, bcc–Fe, spinel, wüstite, CuFeO2, Cu2O, Fe2SiO4, Fe2O3 and SiO2 obtained in the previous optimizations of the Cu–O, Fe–O, Cu–Fe, Cu–Fe–O, Cu–O–Si, Fe–O–Si sub-systems.

      PubDate: 2017-09-02T07:41:30Z
  • Experimental investigation and thermodynamic description of the Cu-Cr-Zr
    • Abstract: Publication date: December 2017
      Source:Calphad, Volume 59
      Author(s): Yuling Liu, Peng Zhou, Shuhong Liu, Yong Du
      The Cu-Cr-Zr ternary system was investigated via thermodynamic modeling coupled with key experiments. The isothermal section of the Cu-Cr-Zr system at 1123K was determined by means of optical microscopy, X-ray diffraction and electron probe microanalysis, and the phase transformation temperatures were measured by differential scanning calorimetry. The Cu-Cr sub-binary system was re-assessed with a substitutional solution model for the solution phases to ensure its compatibility in multi-component system. A set of self-consistent thermodynamic parameters for the Cu-Cr-Zr systems was obtained using the CALPHAD (CALculation of PHAse Diagram) approach, and the calculated phase diagram is in a satisfactory agreement with the present experimental results and literature information. An increase of the thermodynamic stability for the CuZr and Cr2Zr phases due to the ternary solubility is verified by calculation.

      PubDate: 2017-08-03T11:16:57Z
  • Thermodynamic description of the Al–Ge–Ni system over the whole
           composition and temperature ranges
    • Abstract: Publication date: September 2017
      Source:Calphad, Volume 58
      Author(s): Chenyang Zhou, Jiaxin Cui, Cuiping Guo, Changrong Li, Zhenmin Du
      The phase equilibria and thermodynamic properties of the Al–Ge–Ni system are useful for understanding the diffusion process during the transient liquid phase (TLP) bonding. In this work, the thermodynamic description of the Al–Ge–Ni system over the whole composition and temperature ranges was performed by means of the CALPHAD (CALculation of PHAse Diagrams) method. The enthalpies of mixing of the liquid phase, three isothermal sections at 973, 823, and 673K and nine vertical sections at 10, 20, 35, 55, 60, 70, 75, and 80at% Ni and at a constant Al:Ni ratio of 1:3 were taken into account in the present optimization work. A set of self-consistent thermodynamic parameters of the Al–Ge–Ni system was first obtained. The liquidus projection and reaction scheme were constructed according to the thermodynamic parameters obtained in this work. The phase equilibria and thermodynamic properties calculated by the present thermodynamic description show satisfactory agreement with the available experimental information.

      PubDate: 2017-07-24T11:01:09Z
  • Ti-17 volatilization under vacuum: Investigation of the activity
           coefficients at 1900°C
    • Abstract: Publication date: September 2017
      Source:Calphad, Volume 58
      Author(s): Colin Reimer, Julien Jourdan, Jean-Pierre Bellot
      Vacuum processing techniques are a valuable industrial tool for the processing of reactive metals and alloys. However, drawbacks caused by the selective volatilization of alloying elements lead to an hard prediction of final alloy composition. By understanding the behaviour of the alloying elements and the interactions between them, improved compositional accuracy can be achieved. The evaluation of the activity coefficients is a key property that relates partial vapor pressure with the Langmuir law to accurately predict the mass flux of the individual elements in an alloy. This study takes a look at the grade Ti-17 which exhibits a relative large number of alloying elements. By using an electron beam furnace and a vapor deposition apparatus the necessary measurements were made to evaluate activity coefficients for each of the volatizing elements in the alloys including Aluminum, Chromium, Tin. Comparisons were made between experiments and the findings suggest that the primary interactions between the alloying elements with titanium result in small deviations between alloys. The results for the experiments provided reliable and repeatable results.

      PubDate: 2017-07-12T10:01:11Z
  • Experimental investigation and thermodynamic assessment of the
           Mo–Ni–Zr ternary system
    • Abstract: Publication date: September 2017
      Source:Calphad, Volume 58
      Author(s): Shimin Wang, Cong Zhang, Yong Du, Yingbiao Peng, Yafei Pan, Peng Zhou, Liya Dreval
      The isothermal section of the Mo–Ni–Zr system at 1100°C was investigated by characterization of eight equilibrium alloys. X-ray diffraction (XRD) and electron probe microanalysis (EPMA) were used to identify the stable phases and obtain their compositions. The Mo–Ni–Zr system was then optimized by means of CALPHAD (CALculation of PHAse Diagrams) technique with the consideration of experimental data obtained in the present work and reported in the literature. The liquid, fcc, bcc and hcp solution phases, were modeled with (sub-)regular solution model. The compound Zr65Mo18−xNi16.5+x (τ1, cF96-Ti2Ni) was described as Zr2(Mo, Ni) based on its crystal structure and solubility range. While τ2 (Zr65Mo27.3Ni7.7) phase was modeled as a stoichiometric compound due to its limited homogeneity range. A set of self-consistent thermodynamic parameters for the Mo–Ni–Zr system was finally obtained. Comprehensive comparisons between the calculated and experimental phase diagram data show that the experimental information is satisfactorily accounted for by the present thermodynamic description. The liquidus projection and reaction scheme of the Mo–Ni–Zr system were also generated by using the present thermodynamic parameters.

      PubDate: 2017-07-12T10:01:11Z
  • Updating the estimated assemblage of stable phases in a Gibbs energy
    • Abstract: Publication date: September 2017
      Source:Calphad, Volume 58
      Author(s): M.H.A. Piro
      Several numerical strategies are presented that can be used to effectively and efficiently update the estimated assemblage of stable phases in a Gibbs energy minimizer. Decisions must be made in selecting which phase should be added to or withdrawn from the system, the order in which certain combinations should be considered, testing procedures of the appropriateness of a candidate system for further consideration, etc. The manner in which these methods are performed have a profound effect on the performance and reliability of such calculations; without effective strategies, the solution may not converge. While these matters are somewhat straightforward for relatively small systems, far greater challenges are experienced in large systems containing many chemical elements. These matters will be discussed and effective solutions that have been integrated into thermochimica throughout the course of its development will be presented.

      PubDate: 2017-07-03T09:07:26Z
  • Software tools for high-throughput CALPHAD from first-principles data
    • Abstract: Publication date: September 2017
      Source:Calphad, Volume 58
      Author(s): Axel van de Walle, Ruoshi Sun, Qi-Jun Hong, Sara Kadkhodaei
      We present a set of software tools that largely automate the process of converting ab initio data into thermodynamic databases that can readily be imported into standard thermodynamic modeling softwares. These tools are based on the Special Quasirandom Structures (SQS) formalism, extended to transparently handle, not only traditional fcc, bcc and hcp solid solutions, but also multiple-sublattice structures with possible sublattice disorder. A large database of pre-generated SQS is provided that covers over 30 of the most common multi-sublattice structures and spans the composition ranges of each of their sublattices. In addition, we exploit a theoretically justified and robust method to address the issue of assigning free energies to mechanically unstable “virtual” phases, thus providing a compelling solution to a long-standing problem in CALPHAD modeling, especially in the context of ab initio data. We also propose a simple low-order approximation scheme to include short-range order effects that requires no additional ab initio input. The resulting thermodyamic database seamlessly combines ab initio data (formation energies and, optionally, vibrational free energies) with elemental Scientific Group Thermodata Europe (SGTE) data. The proposed tools provide a clear path to expand the coverage of high-throughput efforts towards non-stoichiometric phases and non-zero temperatures. The generated free energy models can also provide very good starting points to perform complex thermodynamic assessments, especially in cases where the available experimental data poorly constrain some thermodynamic parameters. The Cu-Pt-W phase diagram is calculated as an example.
      Graphical abstract image Highlights fx1

      PubDate: 2017-06-12T07:40:52Z
  • Thermodynamic and diffusion kinetic studies of the Fe-Co system
    • Abstract: Publication date: September 2017
      Source:Calphad, Volume 58
      Author(s): Jingjing Wang, Xiao-Gang Lu, Naqiong Zhu, Weisen Zheng
      The phase equilibria, thermodynamic properties and diffusion mobilities of the Fe-Co system were carefully assessed through the CALPHAD methods. As an indispensable tool, the first-principles calculations were carried out to study the magnetic moments and the enthalpies of mixing of the bcc_A2, bcc_B2, fcc_A1 and hcp_A3 phases as well as the point defect types of the bcc_B2 phase. In order to verify the heat capacities reported in the literature, new measurements were conducted in a high-temperature calorimetric apparatus using the three-dimensional calorimetric method. Because of the revision of the thermodynamic parameters in the present work, the diffusion mobilities for the fcc_A1 phase were reassessed. The diffusion mobilities for the bcc_A2 phase were established for the first time based on the experimental diffusion coefficients. For the low-temperature bcc_B2 phase, the diffusion couple experiments conducted in the present work show that the diffusion process is sluggish and the interdiffusion coefficients are difficult to determine. Therefore the tracer diffusivities of Co and Fe in the Fe-Co alloys were used to assess the diffusion mobilities for the bcc_B2 phase, while the composition-distance profile of one diffusion couple was served as a validation of its diffusion mobilities.

      PubDate: 2017-06-12T07:40:52Z
  • Experimental investigation of phase equilibria in the Ti-Fe-Cr ternary
    • Abstract: Publication date: September 2017
      Source:Calphad, Volume 58
      Author(s): Lijun Zeng, Libin Liu, Shuaixiong Huang, Ligang Zhang
      Phase equilibria in ternary Ti-Fe-Cr system at 873 and 1173K were investigated in this work. Based on the phase constitutions and phase compositions in 32 samples prepared using the equilibrated alloys, the isothermal sections of the Ti-Fe-Cr ternary system were established. For this system, there were six three-phase regions at both 873 and 1173K, the phase relations at the studied two temperatures are almost the same. Thereinto, two tentative three-phase regions of βCr2Ti + β(Ti) + (Fe, Cr)2Ti and βCr2Ti + β(Ti) + αCr2Ti were deduced near the Ti-Cr side at 1173K. The (Fe, Cr)2Ti phase has a large solubility of Cr, up to 59.1at% at 873K and 59.5at% at 1173K. Moreover, at 873 and 1173K, the homogeneity ranges of the nearly linear ternary compounds τ1 were measured to be 49.9–72.1at% Fe and 52.7–77.2at% Fe, respectively, and the solubility of Cr in (Fe, Cr)Ti were 9.0at% and 10.6at%.

      PubDate: 2017-06-07T03:28:43Z
  • 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
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