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  1. Provenance of code.
  2. Purpose of code.
  3. Specification.
  4. Description of program's operation.
  5. References.
  6. Parameter descriptions.
  7. Error indicators.
  8. Accuracy estimate.
  9. Any additional information.
  10. Example of code
  11. Auxiliary routines required.
  12. Keywords.
  13. Download source code.
  14. Links.

Provenance of Source Code

Jeevan Jaidi
Research Scholar,
Mechanical Engineering Department,
Indian Institute of Science,

E-mail: jaidi@mecheng.iisc.ernet.in

Added to MAP: January 2003.

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This code calculates the variation of surface tension and temperature dependence of surface tension (surface tension coefficient) with temperature for the following cases: (a) pure iron and (b) Fe-S binary alloy system, with a given sulfur content.

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Language: FORTRAN-90
Product form: Source code

Complete program.

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Surface tension, a thermodynamic property, is function of both temperature and concentration. It measures the strength of the bond between two atoms at the free surface. In general, for pure metals and alloys the bond between two atoms decrease with increase in temperature and result in decreased surface tension. Also, for pure metal and alloys the surface tension coefficient is a constant negative value, always, and is the order of 10-4 N/m-K. The presence of surface-active elements, such as sulfur, oxygen, selenium, tellurium, etc., strengthen the surface bonds with increasing temperature and result in increased surface tension and hence surface tension coefficient. Further increasing temperature will break the above surface bonds and result in decrease in surface tension and hence surface tension coefficient. The strengthening of the surface bonds is believed to be due to the macro-segregation of surface active elements.

In general, surface tension as a function of temperature and solute activity for a binary alloy system is expressed by the following semi-empirical relation:

Equation x of reference y.

The temperature dependence of surface tension (surface tension coefficient) as a function of temperature and solute concentration is given by the follwing expression:

Equation x of reference y.


Equation x of reference y.

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  1. C. R. Heiple and J. R. Roper, 1982, Welding J., 61, 97s-102s.
  2. P. Sahoo, T. Debroy and M. J. McNallan, 1988, Metall. Trans., 19B, 483-491.
  3. R. T. C. Choo and J. Szekely, 1991, Welding J., 70, 223s-233s.
  4. R. T. C. Choo, J. Szekely and S. A. David, 1992, Metall. Trans., 23B, 371-384.

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Input parameters

ACTIVITY_S is the solute activity level (wt%).

CONK1 - real
CONK1 is a constant related to the entropy of segregation.

DELHO - real
DELHO is the standard heat of adsorption (J/mol).

DGAMMADT is a constant value of surface tension coefficient of pure metal (N/m-K).

GAMMA_S - real
GAMMA_S is the surface excess of the solute species at saturation (mol/m2).

GAMMA_TM - real
GAMMA_TM is the surface tension of pure metal at the melting temperature (N/m).

T - real array
T is the temperature (absolute).

TMELT - real
TMELT is the melting temperature (absolute).

UNICON - real
UNICON is universal gas constant (J/mol-K).

Output parameters

GAMMA - real array
GAMMA is the surface tension (N/m).

SIGMA - real array
SIGMA is the temperature dependence of surface tension (N/m-K).

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Error Indicators


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No information supplied.

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Further Comments

The input data used in this code is relevent to Fe-S binary alloy system. This code can also be used for any binary alloy system by changing the values of input data.

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1. Program text

Complete program.

2. Program data


3. Program results

Equation x of reference y.
Equation x of reference y.

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Auxiliary Routines


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Binary alloy system, surface active elements, surface tension, surface tension coefficient.

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Download source code

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MAP originated from a joint project of the National Physical Laboratory and the University of Cambridge.

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