scholarly journals Theoretical Modeling to Predict the Thermodynamic, Structural, Surface and Transport Properties of the Liquid Tl−Na Alloys at different Temperatures

2017 ◽  
Vol 4 (1) ◽  
pp. 101
Author(s):  
S. K. Yadav ◽  
L. N. Jha ◽  
D. Adhikari
Keyword(s):  
Structural Properties ◽  
Theoretical Modeling ◽  
Intrinsic Diffusion ◽  
Long Wavelength ◽  
Energy Of Mixing ◽  
Different Temperatures ◽  
Structural Surface ◽  
Free Energy Of Mixing ◽  
Associated Solution Model ◽  
Associated Solution

<p>Theoretical modeling equations are developed by extending regular associated solution model to predict the thermodynamic and structural properties of the liquid Tl−Na alloys at higher temperatures. The thermodynamic properties have been predicted by computing activities of unassociated monomers (a<sub>Tl</sub> and a<sub>Na</sub>) and free energy of mixing (G<sub>M</sub>) at temperatures 673 K, 773 K, 873 K and 973 K. The structural properties have been predicted by computing concentration fluctuation in long wavelength limit (S<sub>CC</sub>(0)), short range order parameter (α<sub>1</sub>) and ratio of mutual to intrinsic diffusion coefficients (D<sub>M</sub>/D<sub>id</sub>) at aforementioned temperatures. These properties have been then correlated with the modified Butler's model to predict the surface properties, such as surface concentrations of free monomers (X<sup>S</sup><sub>Tl</sub> and X<sup>S</sup><sub>Na</sub>) and surface tension (σ) of the alloy at above mentioned temperatures.</p><p><strong>Journal of Nepal Physical Society</strong><em><br /></em>Volume 4, Issue 1, February 2017, Page: 101-110</p>

scholarly journals Thermodynamic and structural properties of Mg-Tl liquid alloy

BIBECHANA ◽  
2012 ◽  
Vol 8 ◽  
pp. 81-89 ◽  
Author(s):  
BP Singh ◽  
D Adhikari ◽  
IS Jha ◽  
BC Kumar ◽  
SK Chaudhary ◽  
...  
Keyword(s):  
Short Range ◽  
Enthalpy Of Mixing ◽  
Mixing Enthalpy ◽  
Mixing Properties ◽  
Long Wavelength ◽  
Energy Of Mixing ◽  
Chemical Complex ◽  
Free Energy Of Mixing ◽  
Associated Solution Model ◽  
Associated Solution

The concentration dependent asymmetry in mixing properties of Mg-Tl liquid alloys at 923 K has been investigated on the basis of regular associated solution model. The concentration of ApB type complex in a regular associated solution of Mg and Tl have been determined. We have then used the concentration of complex to calculate the free energy of mixing, enthalpy of mixing, entropy of mixing, activity, concentration fluctuations in long wavelength limit SCC(0) and the Warren Cowley short-range parameter 1 α .The analysis suggests that heterocoordination leading to the formation of chemical complex Mg2Tl is likely to exist in the melt. The analysis reveals that there is a tendency of unlike atom pairing (Mg-Tl) in Mg-Tl alloy whole range of concentration.Keywords: Mg-Tl alloy; microscopic structure; pairwise interaction energy; chemical short range orderDOI: http://dx.doi.org/10.3126/bibechana.v8i0.5692BIBECHANA 8 (2012) 81-89

scholarly journals Energy Disorder in Liquid Fe-Si Alloy

2011 ◽  
Vol 1 ◽  
pp. 37-40
Author(s):  
D. Adhikari ◽  
I. S. Jha ◽  
B. P. Singh
Keyword(s):  
Pairwise Interaction ◽  
Heat Of Mixing ◽  
Interaction Energies ◽  
Molten State ◽  
Energy Disorder ◽  
Energy Of Mixing ◽  
Free Energy Of Mixing ◽  
Alloy Clusters ◽  
Associated Solution Model ◽  
Associated Solution

The observed asymmetry in the properties of mixing of Fe-Si alloy in molten state is successfully explained on the basis of regular associated solution model. We have determined the free energy of mixing, heat of mixing and entropy of mixing of Fe-Si alloys in molten state at 1873 K. The analysis suggests that heterocoordination leading to the formation of complex Fe 2Si is likely to exist in the liquid and is of a strongly interacting nature. The theoretical analysis reveals that the pairwise interaction energies between the species depend considerably on temperature.Keywords: Liquid alloy; Clusters; Thermodynamic propertiesThe Himalayan Physics Vol.1, No.1, May, 2010Page: 37-40Uploaded Date: 28 July, 2011

scholarly journals Regular Associated Solution Model for the Estimation of Free Energy of Mixing of Binary Liquid Alloys

1970 ◽  
Vol 8 (8) ◽  
pp. 30-33
Author(s):  
D Adhikari ◽  
BP Singh ◽  
IS Jha
Keyword(s):  
Free Energy ◽  
Equilibrium Constants ◽  
Solution Model ◽  
Interaction Energies ◽  
Free Energies ◽  
Scientific World ◽  
Energy Of Mixing ◽  
Free Energy Of Mixing ◽  
Associated Solution Model ◽  
Associated Solution

We have found the equilibrium constants and pairwise interaction energies between the species and the complexes of liquid CuSn, AgAl, FeSi, CdNa and HgNa alloys on the basis of regular associated solution model. These parameters are then used to estimate the free energies of mixing of each alloy. The observed asymmetry in the free energy of mixing of each alloy with respect to concentration is well explained. Key Words: Free energy of mixing; Asymmetry; Binary alloys; Interaction energy. DOI: 10.3126/sw.v8i8.3842 Scientific World Vol.8(8) 2010 pp.30-33

scholarly journals Thermodynamic, structural, surface and transport properties of Au-Ni liquid alloy at 1150 K

BIBECHANA ◽  
2021 ◽  
Vol 18 (1) ◽  
pp. 184-192
Author(s):  
S K Yadav ◽  
N Chaudhary ◽  
D Adhikari
Keyword(s):  
Free Energy ◽  
Transport Properties ◽  
Gibbs Free Energy ◽  
Liquid Alloy ◽  
Concentration Fluctuation ◽  
Excess Gibbs Free Energy ◽  
Long Wavelength ◽  
Energy Of Mixing ◽  
Structural Surface ◽  
Free Energy Of Mixing

Thermodynamic, structural, surface, and transport properties of Au-Ni liquid alloy at 1150 K were computed using different theoretical approaches. The thermodynamic properties, such as excess Gibbs free energy of mixing, enthalpy of mixing, activity and excess entropy of mixing, and structural properties, such as concentration fluctuation in long-wavelength limit and Warren-Cowley short-range order parameter were computed in the framework of Flory’s model. The effect of positive and negative values of the interchange energy parameter on the excess Gibbs free energy of mixing and concentration fluctuation in the long-wavelength limit was also observed. The surface tension and surface concentration of the system were calculated using Butler’s model. In the transport property, the viscosity of the system was calculated using Kaptay and Budai-Benko-Kaptay (BBK) models. BIBECHANA 18 (2021) 184-192

scholarly journals Segregation in Fe-Pd melt at 1873 K

BIBECHANA ◽  
2014 ◽  
Vol 11 ◽  
pp. 86-93
Author(s):  
SK Yadav ◽  
LN Jha ◽  
D Adhikari
Keyword(s):  
Free Energy ◽  
Melting Point ◽  
Theoretical Analysis ◽  
Structural Properties ◽  
Liquid Alloy ◽  
Short Range ◽  
Heat Of Mixing ◽  
Long Wavelength ◽  
Energy Of Mixing ◽  
Free Energy Of Mixing

The thermodynamic and structural properties of Fe-Pd liquid alloys at 1873 K have been computed using regular associated solution model. To compute these functions we have estimated the mole fractions of the complex assuming the existence of FePd3 complex in the melt. The thermodynamic properties such as free energy of mixing (GM), heat of mixing (HM), entropy of mixing (SM) and activity (a) of the melt have been estimated. To understand the microscopic structural properties, we have estimated the concentration fluctuation in long wavelength limit (Scc(0)) and the Warren-Cowley short range parameter (α1). The free energy of mixing was found to be negative at all compositions. But the heat of mixing and the entropy of mixing are found to be positive at all compositions. The equilibrium constant (K) is found be less than negative. The interaction energy parameters (w12, w13 and w23) are all found to be positive and temperature dependent. The theoretical estimation of the concentration fluctuation in long wavelength limit (SCC (0)) is found to be greater than the ideal values throughout the whole range. The theoretical analysis suggests that the Fe-Pd liquid alloy at 1873 K near the melting point is segregating (homo-coordinating) system. The Warren-Cowley short range order parameter is found to be positive which too suggest the homocoordinating (segregating) nature of the system at all compositions. The theoretical analysis also suggests that the Fe-Pd liquid alloy near melting point is weakly interacting system. DOI: http://dx.doi.org/10.3126/bibechana.v11i0.10386   BIBECHANA 11(1) (2014) 86-93

scholarly journals A simple theory of mixtures for the study of the temperature dependence of thermo-structural properties of Al-Ga liquid alloy

2020 ◽  
Vol 31 (3) ◽  
pp. 87-100
Author(s):  
Kritika Khanal ◽  
◽  
Shashit Kumart Yadav ◽  
Devendra Adhikari ◽  
◽  
...  
Keyword(s):  
Free Energy ◽  
Structural Properties ◽  
Excess Free Energy ◽  
Simple Theory ◽  
Temperature Dependent ◽  
Long Wavelength ◽  
Energy Of Mixing ◽  
Theory Of Mixtures ◽  
Free Energy Of Mixing ◽  
Good Agreement

A simple theory of mixtures for symmetric alloys was used to study the thermodynamic and structural properties of the Al-Ga alloy in the liquid state at 1023 K. The computed thermodynamic properties are in a very good agreement with the observed values and show that the alloy is weakly interacting. The computed structural properties show that the Al-Ga alloy is segregating in nature which is in agreement with the observed values. The excess free energy of mixing, activity of monomers and concentration fluctuation in the long wavelength limit was extrapolated to higher temperatures by optimising the temperature dependent parameters. As the temperature increases, the behaviour of the alloy shifts towards the ideality.

scholarly journals Thermodynamic and structural properties of K-Na liquid alloy

BIBECHANA ◽  
2012 ◽  
Vol 9 ◽  
pp. 130-135 ◽  
Author(s):  
I Koirala ◽  
IS Jha ◽  
BP Singh
Keyword(s):  
Structural Properties ◽  
Liquid Alloy ◽  
Diffusion Coefficients ◽  
Short Range ◽  
Short Range Order ◽  
Heat Of Mixing ◽  
Long Wavelength ◽  
Parameter Ratio ◽  
Energy Of Mixing ◽  
Free Energy Of Mixing

The deviation from ideal mixture behavior and concentration dependent symmetry in thermodynamic and structural properties of K-Na liquid alloy is investigated within a simple statistical model. The concentration dependence of the free energy of mixing, heat of mixing, entropy of mixing, concentration fluctuation in the long wavelength limit, Warren-Cowley short range order parameter, ratio of diffusion coefficients of Potassium-sodium alloy at 384 K and activity of the components has got special attention to show a tendency of like atom pairing in the mixture. DOI: http://dx.doi.org/10.3126/bibechana.v9i0.7187 BIBECHANA 9 (2013) 130-135

scholarly journals Regular Associated Solution Model for the Estimation of Heat of Mixing of Binary Liquid Alloys

BIBECHANA ◽  
1970 ◽  
Vol 6 ◽  
pp. 1-8
Author(s):  
D Adhikari ◽  
BP Singh ◽  
IS Jha
Keyword(s):  
Equilibrium Constants ◽  
Pairwise Interaction ◽  
Solution Model ◽  
Heat Of Mixing ◽  
Interaction Energies ◽  
Binary Liquid ◽  
Energy Of Mixing ◽  
Free Energy Of Mixing ◽  
Associated Solution Model ◽  
Associated Solution

We have determined the equilibrium constants and pairwise interaction energies between the species and the complexes of liquid CuSn, AgAl and FeSi, alloys on the basis of regular associated solution model. These parameters are then used to estimate the heat of mixing of each alloy. The observed asymmetry in the heat of mixing of each alloy with respect to concentration is well explained. Key Words: Free energy of mixing; Asymmetry; Binary alloys, interaction energyThe corrected version of this PDF was loaded on 8/12/2010.DOI: 10.3126/bibechana.v6i0.3931BIBECHANA Vol. 6, March 2010 pp.1-8

scholarly journals Thermodynamic, structural, transport and surface properties of Pb-Tl liquid alloy

BIBECHANA ◽  
2015 ◽  
Vol 13 ◽  
pp. 100-113 ◽  
Author(s):  
SK Yadav ◽  
LN Jha ◽  
D Adhikari
Keyword(s):  
Liquid Alloy ◽  
Surface Concentration ◽  
Heat Of Formation ◽  
Concentration Fluctuation ◽  
Heat Of Mixing ◽  
Long Wavelength ◽  
Wavelength Limit ◽  
Energy Of Mixing ◽  
Free Energy Of Mixing ◽  
Experimental Values

Thermodynamic properties, such as free energy of mixing, heat of mixing, entropy of mixing, activities and the microscopic structural properties, such as concentration fluctuation in long-wavelength limit and chemical short-range order parameter of Pb-Tl liquid alloy at 773 K have been studied on the basis of regular associated solution model. We have estimated the mole fractions of the complex and the unassociated atoms assuming the existence of  complex as energetically favoured in the liquid state. The compositional contributions of the heat of mixing of the species Pb and Tl and the heat of formation of the compound to the net enthalpy change have also been studied. The transport properties such as, viscosity and the ratio of mutual and intrinsic coefficients have been studied using different approaches. The surface concentration of Tl atoms has been computed and it has been employed to calculate the surface tension of Pb-Tl liquid alloy. Both the theoretical and the experimental values of the concentration fluctuation in long-wavelength limit are found to be less than the ideal value, revealing that the concerned system is hetero-coordinating in nature. The interaction energies are found to be temperature dependent and respective alloy is found to be weakly interacting system. BIBECHANA 13 (2016) 100-113

Quasi-Chemical Model for Liquid Li-Cd Alloys

1989 ◽  
Vol 44 (6) ◽  
pp. 529-532
Author(s):  
L. C. Prasad ◽  
R. N. Singh
Keyword(s):  
Order Parameter ◽  
Short Range ◽  
Short Range Order ◽  
Chemical Model ◽  
Liquid Alloys ◽  
Range Order Parameter ◽  
Long Wavelength ◽  
Pairwise Interactions ◽  
Energy Of Mixing ◽  
Free Energy Of Mixing

The quasi-chemical model based on pairwise interactions is used to study the concentration dependent thermodynamic properties of Li-Cd liquid alloys. Special attention is given to the concentration-concentration correlation function in the long wavelength limit [Scc(0)] and the chemical short-range order parameter (CSRO). The activity, free energy of mixing, Scc(0) and CSRO are computed as functions of temperature and concentration.

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