Thermodynamic Properties of the Higher Manganese Carbide

Eremenko, V. N.; Lukashenko, G. M.; Polotskaya, R. I.

doi:10.1007/978-1-4684-8598-1_41

Cited by 10 publications

(20 citation statements)

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“…2 and compared with the values of chemical potential associated with our first principles calculations and with experimental measurements of DH f . [36,37] In this figure, the fcc/Cu 2 Mg-C15 coexistence curve suggests that the experimental values reported by King and Kleppa [36] may be the most accurate, since they exhibit excellent agreement with the EMF data of Eremenko et al [39] Based on this selection and the heat capacity considerations discussed above, the coefficients listed in Table 3 for G…”

Section: Bmentioning

confidence: 87%

“…They are listed in Table 1 along with our first principles calculations, which include these phases as well as the unstable compounds for which experimental data are not available. In addition, we consider the electromotive force (EMF) measurements of activity and chemical potential, reported by Arita et al [38] and Eremenko et al [39] for the Cu-Mg binary system. These are shown in Fig.…”

Section: Bmentioning

confidence: 99%

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Modeling of Thermodynamic Properties and Phase Equilibria for the Cu-Mg Binary System

Zhou

Wang

Shi

et al. 2007

J Phs Eqil and Diff

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The phase equilibria associated with the binary Cu-Mg system are analyzed by applying results from firstprinciples calculations to a general solution thermodynamics treatment. Differing from previously reported models, we employ a four-species association model for the liquid, while the terminal and intermediate solid phases are modeled as substitutional solutions with one or two sublattices, respectively. The zero-Kelvin enthalpies of formation for the intermediate compounds, Cu 2 Mg-C15 (cF24) and CuMg 2 -C b (oF48) are computed using the Vienna Ab-initio Simulation Package (VASP). The Gibbs free energy functions for the individual phases are evaluated, and the resulting binary phase diagram is presented over the full composition range. While the phase diagram we propose exhibits only modest deviation from previously reported models of phase equilibria, our treatment provides better agreement with experimental reports of heat capacity and enthalpy of mixing, indicating a more self-consistent thermodynamic description of this binary system. The phase equilibria associated with the binary Cu-Mg system are analyzed by applying results from first-principles calculations to a general solution thermodynamics treatment. Differing from previously reported models, we employ a four-species association model for the liquid, while the terminal and intermediate solid phases are modeled as substitutional solutions with one or two sublattices, respectively. The zero-Kelvin enthalpies of formation for the intermediate compounds, Cu 2 Mg-C15 (cF24) and CuMg 2 -C b (oF48) are computed using the Vienna Ab-initio Simulation Package (VASP). The Gibbs free energy functions for the individual phases are evaluated, and the resulting binary phase diagram is presented over the full composition range. While the phase diagram we propose exhibits only modest deviation from previously reported models of phase equilibria, our treatment provides better agreement with experimental reports of heat capacity and enthalpy of mixing, indicating a more self-consistent thermodynamic description of this binary system. Keywords

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Section: Bmentioning

confidence: 87%

Section: Bmentioning

confidence: 99%

Modeling of Thermodynamic Properties and Phase Equilibria for the Cu-Mg Binary System

Zhou

Wang

Shi

et al. 2007

J Phs Eqil and Diff

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“…[46][47][48][49] Recently, Stange et al reported the Mn 2-x Sn compound with the Ni 2 In crystal structure and presented the modified phase relation, [50] which was accepted by Okamoto. [51] A thermodynamic calculation of the Mn-Sn phase diagram was carried out by Miettinen.…”

Section: B the Mn-sn Binary Systemmentioning

confidence: 99%

Experimental investigation and thermodynamic calculation of the phase equilibria in the Cu-Sn and Cu-Sn-Mn systems

Liu

Kainuma

Wang

et al. 2004

Metall Mater Trans A

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The phase equilibria in the Cu-rich portion of the Cu-Sn binary and Cu-Sn-Mn ternary systems have been determined using the diffusion-couple method, differential scanning calorimetry (DSC), high-temperature electron diffraction (HTED), and high-temperature X-ray diffraction (HTXRD) techniques. The present experimental results on the binary Cu-Sn system show the presence of the two-stage, second-order reaction in the bcc-phase region, rather than a two-phase equilibrium between the disordered bcc (A2) and the ordered bcc (D0 3 ) phases, as reported before. Phase equilibria in the Cu-Sn-Mn ternary system in the composition range of 0 to 30 at. pct Sn and 0 to 30 at. pct Mn at 550 °C, 600 °C, 650 °C, and 700 °C have been determined, and a ternary compound (Cu 4 MnSn) with a very small solubility has been detected. A thermodynamic analysis of the Cu-Sn-Mn ternary system including the Cu-Sn and Mn-Sn binary systems has also been carried out by the CALPHAD (Calculation of Phase Diagrams) method, in which the Gibbs energy of the bcc phase is described by the two-sublattice model in order to take into account the second-order A2/B2 ordering reaction. A consistent set of optimized thermodynamic parameters for the Cu-Sn-Mn system for describing the Gibbs energy of each phase results in a better fit between calculation and experiment.A2 → B2 → D0 3

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“…9,14,26 Assuming that MgCu 2 is stoichiometric and a -phase = 1, activity of copper can be assessed by application of the Gibbs-Duhem equation 26 ln a (4) and (5) …”

Section: Resultsmentioning

confidence: 99%

“…In these studies e.m.f. 9,10 and calorimetric [11][12][13] methods were used, as well as vapor pressure measurements. [14][15][16][17] The main purpose of the theoretical studies confined to the Cu-Mg system 18,19 was to develop computational methods and to provide the data for further investigations of ternary and industrial multicomponent alloys based on Cu-Mg.…”

mentioning

confidence: 99%

A high temperature mass spectrometric study of the thermodynamic properties of Cu-Mg solid alloys

Шилов¹,

Holappa²,

Stolyarova

1998

Rapid Commun. Mass Spectrom.

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Received 5 June 1998; Revised 2 July 1998; Accepted 4 July 1998Studies of the Cu-Mg binary system were encouraged for technological reasons by the general interest for a better theoretical understanding of its properties, including its thermodynamics, and by the need for a simple system for examining some new experimental and computational models. In the first comprehensive studies 1-3 the general features of the Cu-Mg phase diagram were revealed by methods of microscopy and thermoanalysis, also the problems of preparation of the samples of alloys were discussed in detail. The ranges of solubility of terminal solutions of Cu and Mg were determined 4-6 by microstructure analysis and measurements of the electrical conductivity of alloys. By X-ray diffraction together with thermal analysis and micrography 7,8 the existence of the non-stoichiometric phase MgCu 2 was confirmed. More recent experimental work focused primarily on the thermodynamic properties of Cu-Mg alloys. In these studies e.m.f.9,10 and calorimetric 11-13 methods were used, as well as vapor pressure measurements.14-17 The main purpose of the theoretical studies confined to the Cu-Mg system 18,19 was to develop computational methods and to provide the data for further investigations of ternary and industrial multicomponent alloys based on Cu-Mg.Amongst the experimental methods that allow the study of the thermodynamic properties of the Cu-Mg system the Knudsen effusion mass spectrometry has an advantage, providing the simultaneous measurement of the partial vapor pressures of all components of the alloy. However, the results of Smith and Christian 14 obtained by the effusion method without a mass spectrometric analysis of the vapor phase do not fit well with the data reported by other authors and hence were not taken into account. 19,20 The values of activities reported in Ref. 20 measured by the mass spectrometric method are in better agreement with the results obtained by other methods. For a further assessment of the validity of the data found by the effusion method a more detailed analysis of these data is performed, the thermodynamic functions are derived and the results are discussed. EXPERIMENTALThe present study was carried out using the high temperature mass spectrometric Knudsen effusion method.21-23 A quadrupole mass spectrometer QMG 420 (Balzers, Liech Heinstein) was attached to a vacuum chamber containing a high temperature furnace and a temperature regulated support with an effusion cell. The assembly made it possible to perform complete vaporization experiments as well as comparison of ion currents in both direct and successive modes. A detailed description of the experimental setup can be found in Ref. 24. SamplesThe samples of Cu-Mg alloys containing 41.0, 70.5, 80.0 atomic fraction Mg were prepared in tantalum crucibles by melting pure Cu and Mg (99.99% purity). They were heated in vacuum to 50 K above the melting point and kept at this temperature for 15 min. The vertical dimensions of the resulting sample pieces (`4 mm) are suppose...

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Thermodynamic Properties of the Higher Manganese Carbide

Cited by 10 publications

References 0 publications

Modeling of Thermodynamic Properties and Phase Equilibria for the Cu-Mg Binary System

Modeling of Thermodynamic Properties and Phase Equilibria for the Cu-Mg Binary System

Experimental investigation and thermodynamic calculation of the phase equilibria in the Cu-Sn and Cu-Sn-Mn systems

A high temperature mass spectrometric study of the thermodynamic properties of Cu-Mg solid alloys

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