Thermodynamics of the Ni3Ga phase with the L12 superlattice structure

Chang, Y. A.; Hsiao, Y.Y.

doi:10.1016/0036-9748(76)90149-6

Cited by 10 publications

(4 citation statements)

References 2 publications

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“…Most of them based their evaluations on some type of disorder parameters which were usually defined as the concentrations of point defects at the stoichiometric composition. Such a model was also derived for L1 2 -phases by Chang and co-workers [12] and applied to Ni 3 Al [13] and Ni 3 Ga [14] assuming purely substitutional disorder caused by anti-structure atoms. A similar approach was recently presented by Ikeda et al [15] based on a long-range order parameter…”

Section: Discussionmentioning

confidence: 99%

“…It has been argued by two of the authors [11] that the combination of accurate thermodynamic measurements and statistical thermodynamics may be a very powerful tool to determine the main type of point defects present in a non-stoichiometric compound at a given temperature and, in particular, the compositional variation of their concentrations. Such a simple statistical model was presented by Chang and co-workers [12] and applied to the intermetallics Ni 3 Al [13] and Ni 3 Ga [14], and a very similar approach was recently used by Ikeda et al to describe Ni 3 Al [15]. However, in both cases only anti-structure atoms were allowed as defects, and the evaluations were based on a corresponding disorder or long-range order parameter.…”

Section: Introductionmentioning

confidence: 99%

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A Statistical-Thermodynamic Model for Intermetallic Phases with L12-Structure and Its Application to the Compound Ni3Al

Krachler

Semenova

Ipser

1999

phys. stat. sol. (b)

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A statistical‐thermodynamic model for binary nonstoichiometric L12‐phases has been developed based on a mean‐field approximation. Vacancies and anti‐structure atoms are allowed on both sublattices as possible point defects, and the expressions for the defect concentrations as functions of composition and temperature have been derived. From these the compositional variation of the thermodynamic activities of the two components can be calculated using energies of formation of the four types of point defects as parameters. The model equations are applied to the intermetallic compound Ni3Al using defect formation energies from the literature, and the corresponding curves are compared with experimental aluminum activities at 1400 and 1600 K. As it turns out, one particular set of energy parameters (Debiaggi et al., 1996) gives clearly the best agreement, resulting in very low vacancy concentrations (of the order of 10—7 to 10—9). Thus the thermal disorder and the deviation from stoichiometry in Ni3Al is in principle caused entirely by anti‐structure atoms. Their concentrations (referred to the total number of lattice sites) at the exactly stoichiometric composition are found to be 0.0075 at 1400 K, i.e. 3% of the Al‐sites are occupied by Ni‐atoms and 1% of the Ni‐sites by Al‐atoms. It is argued that this combination of statistical thermodynamics and experimental activity data permits an assessment of the reliability of the theoretically derived values of the defect formation energies in non‐stoichiometric phases.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Statistical-Thermodynamic Model for Intermetallic Phases with L12-Structure and Its Application to the Compound Ni3Al

Krachler

Semenova

Ipser

1999

phys. stat. sol. (b)

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“…Early research work on the disorder in Ni 3 Ga was presented by Chang and Hsiao, [8] who applied a statistical thermodynamic model to experimental Ga activities measured by Katayama et al [9] and by Pratt and Bird. [10] They assumed only substitutional disorder in the Ni 3 Ga phase and neglected vacancies altogether.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic assessment of the Ni-Ga system

Yuan

Qiao

Ipser

et al. 2004

J Phs Eqil and Diff

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Phase diagram and thermodynamic properties of the Ni-Ga system are assessed based on the CALPHAD approach, using all available experimental data and applying appropriate thermodynamic models. The liquid phase and the Ni-based solid solution (Ni) are treated as disordered solutions. The thermodynamic behavior of the ordered intermetallic compounds with appreciable ranges of homogeneity, Ni 3 Ga and NiGa, are described by a two-sublattice model, and the order-disorder transformation between Ni 3 Ga and fcc-(Ni) is also explicitly considered in this work. The other five intermetallic compounds are treated as stoichiometric line compounds. The phase diagram and the thermodynamic properties calculated from the optimized model parameters are in good agreement with most of the experimental data.

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“…Various authors present statistical-thermodynamic models and derive expressions for the composition dependence of the thermodynamic properties in ordered intermetallic phases. [18,[22][23][24][25][26][27][28][29][30][31] Most of these models are based on evaluations of disorder parameters which were usually defined as the concentrations of point defects at the stoichiometric composition. Such models were also developed for B2 and L1 2 phases, [3][4][5][6][7][8]18,20,22,[25][26][27][28][29]31,32] assuming purely substitutional disorder caused by anti-structure atoms.…”

Section: Application Of the Wagner-schottky Model And Ab-initio Calcumentioning

confidence: 99%

Binary L1₂ Intermetallics: A Statistical‐Thermodynamic Modeling of Ordering Phenomena, Behavior and Properties

Semenova

2012

Zeitschrift anorg allge chemie

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The main objective of this paper is aimed towards a correct statistical-thermodynamic modeling and description of the effects and changes associated with the creation of different defects in the crystal structure and their connection and influence on the properties of the binary L1 2 intermetallic systems. This was done by the using of a General Defect Correlation Model (GDCM), employing applications of the Bragg-Williams-Gorsky mean-field approximation. The obtained results are compared to a model based on the Wagner-Schottky approach with application of the grand canonical ensemble for noninteracting point defects for description of the arrangement of anti-* Dr. O. Semenova

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Thermodynamics of the Ni3Ga phase with the L12 superlattice structure

Cited by 10 publications

References 2 publications

A Statistical-Thermodynamic Model for Intermetallic Phases with L12-Structure and Its Application to the Compound Ni3Al

A Statistical-Thermodynamic Model for Intermetallic Phases with L12-Structure and Its Application to the Compound Ni3Al

Thermodynamic assessment of the Ni-Ga system

Binary L1₂ Intermetallics: A Statistical‐Thermodynamic Modeling of Ordering Phenomena, Behavior and Properties

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Thermodynamics of the Ni3Ga phase with the L12 superlattice structure

Cited by 10 publications

References 2 publications

A Statistical-Thermodynamic Model for Intermetallic Phases with L12-Structure and Its Application to the Compound Ni3Al

A Statistical-Thermodynamic Model for Intermetallic Phases with L12-Structure and Its Application to the Compound Ni3Al

Thermodynamic assessment of the Ni-Ga system

Binary L12 Intermetallics: A Statistical‐Thermodynamic Modeling of Ordering Phenomena, Behavior and Properties

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Binary L1₂ Intermetallics: A Statistical‐Thermodynamic Modeling of Ordering Phenomena, Behavior and Properties