Program Library

- Provenance of code.
- Purpose of code.
- Specification.
- Description of subroutine's operation.
- References.
- Parameter descriptions.
- Error indicators.
- Accuracy estimate.
- Any additional information.
- Example of code
- Auxiliary subroutines required.
- Keywords.
- Download source code.
- Links.

H.K.D.H. Bhadeshia,

Phase Transformations Group,

Department of Materials Science and Metallurgy,

University of Cambridge,

Cambridge, U.K.

To calculate the free energy change accompanying the transformation from austenite to ferrite of the same chemical composition, including a Zener ordering term.

Language: | FORTRAN |

Product form: | Source code |

FUNCTION MAP_STEEL_FTO1(H,S,X,T,W,W1,H1,S1,F,AJ,AJ1,R)

DOUBLE PRECISION H,S,X,T,W,W1,H1,S1,F,AJ,AJ1,R

MAP_STEEL_FTO1 calculates the free energy change accompanying the transformation from austenite to ferrite of the same chemical composition, including a Zener ordering term. The latter describes the ordering of carbon atoms that leads to the the body-centred cubic lattice of ferrite becoming body-centred tetragonal. The degree of ordering increases as the carbon concentration increases, or as the transformation temperature decreases.

- C. Zener, Trans. AIME,
__167__, (1946), 550. - J.C. Fisher, Metals Transactions,
__185__, (1949), 688-690. - H.K.D.H. Bhadeshia and D.V. Edmonds, Acta Metallurgica,
__28__, (1980), 1265-1273.

**H**- real- H is the excess partial molar enthalpy of solution of carbon in austenite (in joules per mole, Jmol
^{-1}). **S**- real- S is the excess partial molar entropy of solution of carbon in austenite (in joules per mole per kelvin, Jmol
^{-1}K^{-1}). **X**- real- X is the mole fraction of carbon in the ferrite.
**T**- real- T is the temperature (in kelvin).
**W**- real- W is the carbon-carbon interaction energy in austenite (in joules per mole, Jmol
^{-1}). **W1**- real- W1 is the carbon-carbon interaction energy in ferrite (in joules per mole, Jmol
^{-1}). **H1**- real- H1 is the excess partial molar enthalpy of solution of carbon in ferrite (in joules per mole, Jmol
^{-1}). **S1**- real- S1 is the excess partial molar entropy of solution of carbon in ferrite (in joules per mole per kelvin, Jmol
^{-1}K^{-1}). **F**- real- F is the energy (in joules).
**AJ**- real- AJ = 1 - e
^{(W/RT)}, where R is the universal gas constant. **AJ1**- real- AJ1 = 1 - e
^{(W1/RT)}, where R is the universal gas constant. **R**- real- R is the universal gas constant (in joules per mole per kelvin, Jmol
^{-1}K^{-1}).

**MAP_STEEL_FTO1**- real- MAP_STEEL_FTO1 is the free energy change accompanying the transformation from austenite to ferrite of the same chemical composition.

None.

No information supplied.

None.

DOUBLE PRECISION H,S,X,T,W,W1,H1,S1,F,AJ,AJ1,R,XFTO DOUBLE PRECISION MAP_STEEL_FTO1 INCLUDE 'map_constants_gas.f' READ (5,*) H,S,H1,S1,W,W1 READ(5,*) X,T,F,AJ,AJ1 XFTO=MAP_STEEL_FTO1(H,S,X,T,W,W1,H1,S1,F,AJ,AJ1,R) WRITE (6,*) XFTO STOP END

None supplied.

None supplied.

None.

austenite, ferrite, free energy change

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