scholarly journals Theoretical assessment for the mixing properties of AlMg liquid alloys at 1073K

2021 ◽  
Vol 2070 (1) ◽  
pp. 012074
Author(s):  
Shayista Ahmad ◽  
M P Sah ◽  
R P Chaudhary ◽  
I S Jha ◽  
J Mandal
Keyword(s):  
Free Energy ◽  
Short Range ◽  
Short Range Order ◽  
Liquid Alloys ◽  
Mixing Properties ◽  
Long Wavelength ◽  
Entropy Of Mixing ◽  
Mixing Energy ◽  
Energy Of Mixing ◽  
Free Energy Of Mixing

Abstract The alloying behavior of AlMg alloy in the liquid form at 1073 K has been theoretically investigated in the framework of four-parameter model which is based on Maclaurin series. The analytical expressions for thermodynamic functions such as excess free mixing energy, free mixing energy, enthalpy of mixing and entropy of mixing and microscopic functions such as concentration fluctuations at the long wavelength limit and Warren-Cowley chemical short range order parameter have been derived. These expressions have been used to compute the excess Gibbs free energy of mixing, Gibbs free energy of mixing, activity, enthalpy(heat) of mixing, excess entropy of mixing, entropy of mixing, concentration fluctuations in long wavelength limit and Warren-Cowley short range order parameters of AlMg liquid alloys at 1073 K. The investigation shows the excellent concurrence between the experimental and theoretical measurements of the mixing properties of AlMg liquid alloys at 1073 K. Interaction parameters of energy depends on temperature.

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.

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 Structural study of liquid Sn-Tl alloys

BIBECHANA ◽  
2014 ◽  
Vol 11 ◽  
pp. 46-52
Author(s):  
RP Koirala ◽  
IS Jha ◽  
BP Singh ◽  
D Adhikari
Keyword(s):  
Order Parameter ◽  
Short Range ◽  
Short Range Order ◽  
Theoretical Models ◽  
Temperature Dependent ◽  
Long Wavelength ◽  
Energy Interaction ◽  
Energy Of Mixing ◽  
Free Energy Of Mixing ◽  
The Comparative Study

The concentration fluctuations in long wavelength limit, Scc(0) and the Warren-Cowley short range order parameter (α1) are important microscopic functions which provide valuable information about the local arrangements of the constituent atoms in the alloy melts. In order to investigate the nature of atomic ordering in Sn-Tl alloy in the molten state at 723K, we have computed these functions using theoretical models. The models satisfactorily explain the small asymmetry observed in the experimental data of free energy of mixing of the alloy. The comparative study further reveals that the energy interaction parameters are temperature dependent and the Sn-Tl alloy is weakly interacting segregating system. DOI: http://dx.doi.org/10.3126/bibechana.v11i0.10379   BIBECHANA 11(1) (2014) 46-52

scholarly journals Entropy of Mixing of Liquid NaCd System

1970 ◽  
Vol 10 ◽  
pp. 105-107
Author(s):  
S. K. Chatterjee ◽  
L. C. Prasad ◽  
A. Bhattarai
Keyword(s):  
Solid Phase ◽  
Excess Free Energy ◽  
Liquid Alloys ◽  
Compound Formation ◽  
Mixing Properties ◽  
Entropy Of Mixing ◽  
Energy Of Mixing ◽  
Asymmetric Behaviour ◽  
Statistical Mechanical ◽  
Free Energy Of Mixing

The observed asymmetric behaviour of mixing properties of NaCd liquid alloys, with smaller negative value for excess free energy of mixing (-4.4919KJ) has aroused our interest to undertake a theoretical investigation of this system.The existence of an intermetallic compound in the solid phase, which is manifested in the phase diagram,  may be one of the factors for the anomalous behaviour of property of mixing. A simple statistical mechanical theory based on complex formation model (the complex is formed by the preferential arrangement of A and B constituent atoms of the alloy AB ;( μA + νB = Aμ Bν) has been used to investigate the phenomena of compound formation in NaCd liquid alloys through the study of entropy of mixing through out the whole concentration range.Nepal Journal of Science and Technology Volume 10, 2009 December Page: 105-107 

scholarly journals Heat of Mixing of some Binary Liquid Alloys

1970 ◽  
Vol 7 (7) ◽  
pp. 96-99
Author(s):  
BK Kanth ◽  
SK Chakrabarti
Keyword(s):  
Free Energy ◽  
Successive Approximation ◽  
Chemical Model ◽  
Heat Of Mixing ◽  
Liquid Alloys ◽  
Atomic Composition ◽  
Entropy Of Mixing ◽  
Binary Liquid ◽  
Energy Of Mixing ◽  
Free Energy Of Mixing

There are a large number of binary liquid alloys the thermodynamic properties of mixing of which are not symmetrical about the equi-atomic composition-deviating maximally from those of the ideal alloys. Here we have considered three such alloys-indium-sodium, cadmium-sodium and copper-tin-and tried to calculate their heat of mixing at different concentrations of the ingredients. The liquidus lines of these alloys reveal that the constituent species form complexes. So, we have considered a quasi-lattice chemical model for computation of the thermodynamic entities. It is a statistical model in which grand partition function is used assuming that the energy of a given nearest neighbour bond is different if it belongs to the complex than if it does not. For each alloy we have started with the expression for excess free energy of mixing according to this model and computed the free energy of mixing for different concentrations of the metals within it by deriving the value of interaction parameters through successive approximation method. Thereafter, the expression for excess entropy of mixing is taken into account and the entropy of mixing is computed for different concentrations after finding out the temperature derivative of interaction parameters by the method of successive approximation. Finally the heat of mixing is calculated from these free energy of mixing and entropy of mixing on using the standard thermodynamic relation. The results explain the observed asymmetry in the heat of mixing of the said binary liquid alloys around equi-atomic composition. Key words : Binary liquid alloy; Quasi-lattice chemical model; Heat of mixing DOI: 10.3126/sw.v7i7.3836 Scientific World Vol.7(7) 2009 pp.96-99

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 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

THERMODYNAMICS OF COMPOUND FORMING MOLTEN Cu–In ALLOYS

2008 ◽  
Vol 22 (27) ◽  
pp. 4833-4844 ◽  
Author(s):  
Y. A. ODUSOTE
Keyword(s):  
Free Energy ◽  
Thermodynamic Properties ◽  
Gibbs Free Energy ◽  
Chemical Diffusion ◽  
Interaction Parameters ◽  
Ideal Behavior ◽  
Mixing Properties ◽  
Long Wavelength ◽  
Energy Of Mixing ◽  
Free Energy Of Mixing

A study of the thermodynamic properties of Cu in molten Cu – In alloys has been explained using a compound formation model. We use the model to deduce information on thermodynamic properties of the alloy such as the Gibbs free energy of mixing, the enthalpy and entropy of mixing. In this study, we first model the Gibbs free energy in terms of the interaction parameters. Sequel to this, the interaction parameters are utilized to quantify properties such as the concentration–concentration fluctuations in the long wavelength limit, the Warren–Cowley short-range order parameter, and the chemical diffusion. Both positive and negative deviations from Raoultian behavior and concentration-dependent asymmetry in the mixing properties of CuIn 4 liquid alloys were reported. Our analysis suggest that the liquid alloy undergoes a transformation from an ordered ( In -rich end) to segregating ( Cu -rich end) state. The system also exhibits ideal behavior at the Cu -rich end.

scholarly journals Chemical Ordering in Na-Pb and Na-Hg Binary Liquid Alloys

2017 ◽  
Author(s):  
Ayideji Akintunde Ajayi ◽  
Enoch Debayo Ogunmola
Keyword(s):  
Binary Alloy ◽  
Liquid Alloy ◽  
Energy Parameter ◽  
Liquid Alloys ◽  
Mixing Properties ◽  
Long Wavelength ◽  
Chemical Ordering ◽  
Energy Of Mixing ◽  
Free Energy Of Mixing ◽  
Liquid Binary Alloy

A simple model has been used to investigate the nature of chemical order in Na-Pb and Na-Hg liquid binary alloy at 700K and 673K respectively. The energy parameter obtained from the model was used to calculate the concentration dependent mixing properties such as Gibb’s free energy of mixing, Concentration fluctuations in the long wavelength limit and the Warren-Cowley chemical short range order parameter. Results obtained showed that both alloys are hetero-coordinated throughout the entire concentration and there is tendency for segregation and demixing to take place in the liquid alloys. We observed that Na-Hg liquid alloy is more strongly interacting binary alloy and chemically ordered than Na-Pb liquid alloy.

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