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Research Article :

Modeling, Simulations, Predictions, Calculations and Thermodynamic Assessments of Cobalt-Ferric Binary Alloys System Using Calphad Method and Pbine Database


Waseem Ullah Shah, Dil Faraz khan, Shahzeb Burki, Mohib Ullah Khan and Haiqing Yin

Abstract

This research article reports simulations and prediction based calculation for Co-Fe system under the application of Calphad method and thermo-calc package. At different elevated temperature of 1200k, 1225k 1nd 1250k the said system is modeled and corresponding behavior of Gibbs free energy, phase diagram and activity curve is monitored. As per calculation the Gibbs energy curve is correspond to its negative era which shows the actual stability application of the said alloy system. The alloying element shows strong interaction amongst which results negative deviation from Roults law in activity era. At 1250k the activity value becomes maximum with same negative deviation. This shows the applicability and reliability of the said alloy system.

Full-Text

Introduction

 

The modeling and simulation study is the worst need of ongoing technologies as per the costly slandered and difficult pattern of experimental era. As by modeling we can reduce the time and cost with precise calculations of thermodynamic parameters gradually as calculated by Gibbs for thermodynamics and phase based equilibria. In 1929 an Elman predicted the magnetic sense of alloys Fe-Co system through high Curie temperature and predicted its reportable permeability and saturation most magnetizations [1,2].

 

The thermodynamic parameters of the said iron-cobalt system have been studied well by those electrical engines based on magnetic properties and materials has results best prediction of this field as discussed by the software and flexible tool thermo cal is used for various thermodynamic calculations and predictions and also helpful by solving and interaction among various elements with many ideal and non-ideal based behaviors .1n 1981 the first version of this package was installed and in 2002 their modern and many database version is established with various thermo dynamical calculation capacity with description in 1985 by Erwin povoden, et al. [3-8].

 

Calphad Method

 

It is the calculation of phase diagrams method which is useful for finding thermodynamic parameters of many materials with prescribed phase diagrams and phase equilibria, it has many modules for calculations and simulations, recently it has been updated for many thermodynamic properties of different materials in form of molar volume, thermodynamic elastic moduli, and phase like properties, their range of validity is also applicable for processing elements verses composition molar and molar temperature verses Activity with thermodynamic and optical properties, all that calculation is done by calculation of phase diagram method [9-12].

 

Results and Discussion


 

A) 1200K


B) 1225K


C)1250K

Figure 1: Molar activity curves at respective 1200K, 1225K, and 1250K temperature.



A) 1200K

B) 1225K

C) 1250K

Figure 2: Gibbs energy curves at respective 1200K, 1225K, and 1250K temperature.



Figure 3: Phase diagram of the Co-Fe binary alloy system.

 

In this research paper the thermodynamic calculations with valid predictions through PBINE database is employed at various temperatures of 1200K, 1225K, 1250K, the activity behaviors is investigated with phase equilibrium and all module used with lowering occurs in Gibbs energy curve as shown by (Figures 1 and 2).

 

Here in calculation, the activity is found increasing as with temperature and all the deviation here is accordance with Roults law ideal curve [13]. As concern with calculated phase diagrams it is in accordance with literatures. Thermodynamic analysis of Co-Fe system is carried out by getting better description for five stable phases founded in Co-Fe binary system. The four among them hcp,fcc,bcc and liquid ate founded the stable phases in Co-Fe system by considering substitution solution phases, the molar Gibbs energies of the particular phases are being calculated by sub-regular solution and substitution model. As their Gibbs energy is analyzed as according to Inden, et al. and modified by k.oikawa, et al. [13-15].

 

Table 1: Database Thermodynamic Phase Calculation at Temperature: 1200K, 1225K, and 1250for System Co-Fe.


Where in Gibbs energy model, oGcr and oGfe are Fe, Co pure phases in solution, as xi denotes molar fraction of elements in solution, as Fe and Co mole fraction in solution, while the excess energy is shown by constant parameter β ij. Gm is the magnetic part of Gibbs energy. As by temperature dependent section, we have


Where mL ij, are the excess binary energies of binary mixing system. While a, b, c, d, e, f are model parameters. The magnetic part of Gibbs energy is given as


as Q ≤ 1, k(α) is normalized state polynomial of temperature, as by bohr magneton number. 

k(α) = -[α-5/10+/497+α-15/315+α-25/1500]/Q

while Q > 1,

Q = (11692-11692p/15975p)+518/1125

then

k(α) = -[α-5/10+/497+α-15/315+α-25/1500]/(11692-11692p/15975p)+518/1125

As p is constant, whose value varies for different phases, for bcc is 0.4 and for other phases is 0.28 [16].

 α, is normalized state temperature coefficient, as α = T/Tc , where Tc is curie temperature for Ferro alloys as well. As seen in Figure 3. The different temperature base phases has been investigated and all the

phase are of activity based on highest strong atomic interaction based, FCC_A1=1 phase is found attached with highest temperature that indicated austenite solid solution for Cobalt-Iron system, all the phases calculated here are at different temperatures and molar compositions are in well accordance with data in literature, in between (400-450)K the magnetic properties occurs in alloy as ferromagnetic era at the concentration of (0.85-1.0%), that region is important for magnetic field industry. 

As our results indicating that at highest temperature range of 1250K, and concentration of (0.4-0.6%) the Gibbs energy goes to its lowest value which shows that the constituent particle is having strong negative interactions and the alloy is reporting best stable behaviors at that temperature although the activity value is also at peak as confirmed from table during calculations, different thermodynamic parameter like volume, enthalpy and entropy verses temperature is varied here for confine result. At 1250k the smooth negative deviation is seen from ideality at the range of 0.25-0.65 of molar composition of alloying elements, the stage indicate here an ideal mixing and solid solution and well good epitaxial growth of the alloying elements.Then lattice elements and brillouin zones have no lack matching of alloy elements at 1250k. at range 0.8-1.0 of composition the well good magnetic properties in said alloy system are having importance for industrial sectors. The table indicates frequent increase in the enthalpy values for increasing heat contents of the alloying elements with increasing temperature up to 1250k shown highest enthalpy of 3.67311E+04 with corresponding Gibbs energy of -6.11253E+04, that indicate the vital stability of the said alloy system at high temperature ranges.

 

Conclusion

Here the thermodynamic calculations and predictions of binary alloy Co-Fe system has been studied using Calphad approach. Thermodynamic analysis involves calculation of phase diagram, Gibbs energy of mixing, excess Gibbs energies, thermodynamic molar activities, and coefficient of activities, partial and integral values of enthalpy for Ag-Cu alloy system at three elevated temperatures 1200K, 1225K, and 1250K. The alloy reports positive deviation from Vegards law and corresponding good negative deviation from Rout’s law ideal Gibbs curve.

 The thermo dynamical validity of (Co-Fe) alloy system has employed here by thermo-calc package, all the simulations, calculations and predictions are carried by Calphad method as per its importance in material design and modeling databases, the temperatures are employed 1200K, 1225K and 1250K positively, the activity is increasing with increasing temperature but at contrast the Gibbs energy retain its negative value to employs the good stability of the said alloy. The austenite phase observed maximum at highest of 1250K temperature and concentration (0.6-0.8)% with negative most Gibbs energy they employs better configuration of the said alloy for mechanical and shear applications with defined corrosion resistance at hand. So at the 1250K the solid solution of the alloy is more ideal behavior which shows no immiscibility gap at highest temperature .at low temperature and concentration the vapor pressure of the solid solution follows Henry law but at increased temperature and concentration it follows Roults law accordance .the activity of the said alloy follow Hess law with corresponding Roults law at the Gibbs curve, which is more important point in the said alloy for material science and engineering fields.

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Corresponding author

Waseem Ullah Shah, Department of physics, University of science and technology Bannu 28100, kpk, Pakistan, E mail: waseemullahshah303@gmail.com

Citation

Shah WU, Khan DF, Burki S, Khan MU and Yin H. Modeling, simulations, predictions, calculations and thermodynamic assessments of cobalt-ferric binary alloys system using calphad method and pbine database (2020) J of Heterocyclics 2: 3-6.



Keywords

(Co-Fe) system, Calphad, Thermo-calc, Thermodynamic calculations.



Keywords