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Subroutine MAP_STEEL_OMEGA

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

Provenance of Source Code

H.K.D.H. Bhadeshia,
Phase Transformations Group,
Department of Materials Science and Metallurgy,
University of Cambridge,
Cambridge, U.K.

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Purpose

To calculate the carbon-carbon interaction energy in austenite, as a function of alloy composition.

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Specification

Language:FORTRAN
Product form:Source code

SUBROUTINE MAP_STEEL_OMEGA(C,W,XBAR,T10,T20,J)

DOUBLE PRECISION C(8),W,XBAR,T10,T20

INTEGER J

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Description

MAP_STEEL_OMEGA calculates the carbon-carbon interaction energy in austenite as a function of the molecular fraction of individual solutes. The free energy of transformation from austenite to ferrite Delta G{gamma alpha} in pure iron is factorised into magnetic and non-magnetic components.

Delta TM and Delta TNM represent the temperature changes, caused by unit concentration x of substitutional solute, to the temperature at which Delta G{gamma alpha} is calculated.

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References

  1. H. I. Aaronson, Domian, and Pound, TMS AIME, 236, (1966), 769.
  2. H. K. D. H. Bhadeshia, Metal Science, (April 1981), 178.
  3. K. R. Kinsman and H. I. Aaronson, Transformation and hardenability in steels, Climax Molybdenum, Ann Arbor, MI, USA, (1967), 33-38.

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Parameters

Input parameters

C(8) - real array of dimension 8
On entry the first seven elements are set to the C, Si, Mn, Ni, Mo, Cr, and V concentrations by weight percent. The eighth element of the array is reserved for the calculation of iron concentration by difference. N.B. This array is used as workspace inside the subroutine and on exit no longer contains the values set before entering the routine.

J - integer
J should not be equal to one the first time this routine is called.

Output parameters

W - real
W is the carbon-carbon interaction energy in austenite, in joules per mol.

XBAR - real
XBAR is the mole fraction of carbon.

T20 - real
T20 = Delta TM is the temperature change (due to the magnetic component), caused by unit concentration of substitutional solute, to the temperature at which the free energy of transformation from austenite to ferrite (Delta G{gamma alpha} is calculated.

T10 - real
T10 = Delta TM - Delta TNM = T20 - Delta TNM,
where Delta TNM is the temperature change (due to the non-magnetic component), caused by unit concentration of substitutional solute, to the temperature at which the free energy of transformation from austenite to ferrite is calculated.

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Error Indicators

None.

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Accuracy

No information supplied.

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Further Comments

XBAR is truncated to five decimal places, so it is set to zero if the mole fraction of carbon is less than 10-5.

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Example

1. Program text

       DOUBLE PRECISION C(8),W,XBAR,T10,T20
       INTEGER I
       READ (5,*) (C(I), I=1,7)
       CALL MAP_STEEL_OMEGA(C,W,XBAR,T10,T20,0)
       WRITE (6,*) W, XBAR, T10, T20
       STOP
       END

2. Program data

0.044   0.34   1.09   0.01   0.01   0.01   0.01

3. Program results

8389.3149527091   0.002   1.0918039312263D-03   -0.45150577743888

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Auxiliary Routines

None.

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Keywords

carbon, interaction energy, austenite, ferrite, alloy, composition

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Download

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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