Materials Algorithms Project
Program Library

Module MAP_Steel_Activity

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.

Conversion to Fortran 90 by S. Cardie
Address as above.

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Purpose

Module containing four public functions which allow the calculation of activity of iron and carbon in austenite.

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Specification

MODULE MAP_Steel_Activity
CONTAINS

   FUNCTION MAP_STEEL_AFEG(T,W,XEQ)
     USE MAP_Util_Global_Data
     IMPLICIT NONE
     REAL(KIND=real_8_30),INTENT(IN):: T,W,XEQ
     REAL(KIND=real_8_30) :: MAP_STEEL_AFEG
   END FUNCTION MAP_STEEL_AFEG

   FUNCTION MAP_STEEL_DAFEG(T,W,XEQ)
     USE MAP_Util_Global_Data
     IMPLICIT NONE
     REAL(KIND=real_8_30),INTENT(IN):: T,W,XEQ
     REAL(KIND=real_8_30) :: MAP_STEEL_DAFEG
   END FUNCTION MAP_STEEL_DAFEG

   FUNCTION MAP_STEEL_CG(T,W,XEQ)
     USE MAP_Util_Global_Data
     IMPLICIT NONE
     REAL(KIND=real_8_30),INTENT(IN):: T,W,XEQ
     REAL(KIND=real_8_30) :: MAP_STEEL_CG
   END FUNCTION MAP_STEEL_CG

   FUNCTION MAP_STEEL_DCG(T,W,XEQ)
     USE MAP_Util_Global_Data
     IMPLICIT NONE
     REAL(KIND=real_8_30),INTENT(IN):: T,W,XEQ
     REAL(KIND=real_8_30) :: MAP_STEEL_DCG
   END FUNCTION MAP_STEEL_DCG

END MODULE MAP_Steel_Activity

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Description

MAP_STEEL_AFEG calculates the natural log of the activity of iron in austenite, and MAP_STEEL_DAFEG its differential with respect to X (see below). MAP_STEEL_CG and MAP_STEEL_DCG calculate the natural log of the activity of carbon in austenite and its differential with respect to X respectively.

Calculations are based on the theory contained in [1,2,3]. The carbon-carbon interaction energy used is calculated according to [4].

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References

1. J.R. Lacher, Proc. Camb. Phil. Soc. Math. Phys. Sci., 33, (1937), 518.
2. R.H. Fowler and E.A. Guggenheim, Statistical Thermodynamics, Cambridge University Press, New York, (1939).
3. G.J. Shiflet, J.R. Bradley, and H.I. Aaronson, Metall. Trans A, (1978), 999-1008.
4. H.K.D.H. Bhadeshia, Metal Science, 14, (1980), 230-232.

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Parameters

Input parameters

T - real

Absolute temperature.

X - real

Paraequilibrium carbon concentration of austenite (mole fraction).

W - real

Carbon-carbon interaction energy in austenite (J/mol).

Output parameters

MAP_STEEL_AFEG - real

Natural log of activity of iron in austenite.

MAP_STEEL_DAFEG - real

Differential of above with respect to X.

MAP_STEEL_CG - real

Natural log of activity of carbon in austenite.

MAP_STEEL_DCG - real

Differential of above with respect to X.

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Error Indicators

None.

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Accuracy

No information supplied.

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Further Comments

See also the corresponding Fortran 77 routines:

• MAP_STEEL_AFEG
• MAP_STEEL_DAFEG
• MAP_STEEL_CG
• MAP_STEEL_DCG

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Example

1. Program text

PROGRAM MAP_ACTIVITY_TEST
  USE MAP_Util_Global_Data
  USE MAP_Steel_Free_Energy
  USE MAP_Steel_Activity
  IMPLICIT NONE
!
! Variable declarations
!
  REAL(KIND=real_8_30) :: T,W,X,&
                          AFEG, DAFEG, CG, DCG

    READ(5,*) T,W,X

    AFEG  = MAP_STEEL_AFEG(T,W,X)
    DAFEG = MAP_STEEL_DAFEG(T,W,X)
    CG    = MAP_STEEL_CG(T,W,X)
    DCG   = MAP_STEEL_DCG(T,W,X)

    WRITE(6,1000)
    WRITE(6,1001) AFEG,DAFEG
    WRITE(6,1002) CG,DCG
    WRITE(6,1003)

  STOP
1000  FORMAT('Activities and differentials of ...')
1001  FORMAT(3X,'Iron: ',2X,F12.3,F12.3)
1002  FORMAT(3X,'Carbon: ',F12.3,F12.3)
1003  FORMAT(' ... in austenite')
END PROGRAM MAP_ACTIVITY_TEST

2. Program data

 4.7300000000000000E+02
 8.7324743196967374E+03
 1.7560130583041827E-02

3. Program results

Activities and differentials of ...
   Iron:         -0.020     -26.136
   Carbon:        4.377      70.652
 ... in austenite

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Auxiliary Routines

Module:
MAP_Util_Global_Data

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Keywords

activity, carbon, iron, austenite

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Download

Download source code

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