An improved model is presented for the formation of bainitic structures during isothermal heat treatment conditions. The model based on displacive mechanism consists of a new expression for the volume fraction of bainite as a function of time, incorporating a temperature and chemical composition-based expression for the number density of initial nucleation sites and limiting the volume fraction of bainite. The model has been validated with respect to experimental data of high- as well as low-carbon steels. It has been found that the isothermal transformation kinetics is well predicted for all steels.

References

References
1.
Bhadeshia
,
H. K. D. H.
, and
Honeycombe
,
R. W. K.
,
2006
,
Steels: Microstructure and Properties
,
3rd ed.
,
Butterworth-Heinemann
,
Oxford
.
2.
Sawley
,
K.
, and
Kristan
,
J.
,
2003
, “
Development of Bainitic Rail Steels with Potential Resistance to Rolling Contact Fatigue
,”
Fatigue Fract. Eng. Mater. Struct.
,
26
(
10
), pp.
1019
1029
.
3.
Jaques
,
P. J.
,
2004
, “
Transformation-Induced Plasticity for High Strength Formable Steels
,”
Curr. Opin. Solid State Mater. Sci.
,
8
(
3–4
), pp.
259
265
.
4.
De Cooman
,
B. C.
,
2004
, “
Structure-Properties Relationship in TRIP Steels Containing Carbide-Free Bainite
,”
Curr. Opin. Solid State Mater. Sci.
,
8
, pp.
285
303
.
5.
Bhadeshia
,
H. K. D. H.
, and
Christian
,
J. W.
,
1990
, “
Bainite in Steels
,”
Metall. Trans. A
,
21
(
3
), pp.
767
797
.
6.
Aaronson
,
H. I.
,
1969
,
The Mechanism of Phase Transformations in Crystalline Solids
,
The Institute of Metals
,
London
.
7.
Quidort
,
D.
, and
Brechet
,
Y. J. M.
,
2002
, “
A Model of Isothermal and Non Isothermal Transformation Kinetics of Bainite in 0.5% C Steels
,”
ISIJ Int.
,
42
(
9
), pp.
1010
1017
.
8.
Bhadeshia
,
H. K. D. H.
, and
Edmonds
,
D. V.
,
1980
, “
The Mechanism of Bainite Formation in Steels
,”
Acta Metall.
,
28
, pp.
1265
1273
.
9.
Bhadeshia
,
H. K. D. H.
,
1980
, “
BCC-BCC Orientation Relationships, Surface Relief and Displacive Phase Transformations in Steels
,”
Scr. Metall.
,
14
, pp.
821
824
.
10.
Bhadeshia
,
H. K. D. H.
,
1981
, “
A Rationalization of Shear Transformations in Steels
,”
Acta Metall.
,
29
, pp.
1117
1130
.
11.
Santofimia
,
M. J.
,
Caballero
,
F. G.
,
Capdevila
,
C.
,
Garcia-Mateo
,
C.
, and
de Andres
,
C. G.
,
2006
, “
Evaluation of Displacive Models for Bainite Transformation Kinetics in Steels
,”
Mater. Trans.
,
47
, pp.
1492
1500
.
12.
Rees
,
G. I.
, and
Bhadeshia
,
H. K. D. H.
,
1992
, “
Bainite Transformation Kinetics: Part 1 Modified Model
,”
Mater. Sci. Technol.
,
8
, pp.
985
993
.
13.
Santofimia
,
M. J.
,
Caballero
,
F. G.
,
Capdevila
,
C.
,
Garcia-Mateo
,
C.
, and
de Andres
,
C. G.
,
2006
, “
New Model for the Overall Transformation Kinetics of Bainite. Part 1: The Model
,”
Mater. Trans.
,
47
(
10
), pp.
2465
2472
.
14.
Matsuda
,
H.
, and
Bhadeshia
,
H. K. D. H.
,
2004
, “
Kinetics of the Bainite Transformation
,”
Proc. R. Soc. Lond. A
,
460
, pp.
1707
1722
.
15.
Chester
,
N. A.
, and
Bhadeshia
,
H. K. D. H.
,
1997
, “
Mathematical Modelling of Bainite Transformation Kinetics
,”
J. Phys. IV France
,
7
(
c5
), pp.
41
46
.
16.
Van Bohemen
,
S. M. C.
, and
Sietsma
,
J.
,
2008
, “
Modeling of Isothermal Bainite Formation Based on the Nucleation Kinetics
,”
Int. J. Mater. Res.
,
99
(
7
), pp.
739
747
.
17.
Sidhu
,
G.
,
Bhole
,
S. D.
,
Chen
,
D. L.
, and
Essadiqi
,
E.
,
2011
, “
An Improved Model for Bainite Formation at Isothermal Temperature
,”
Scr. Mater.
,
64
, pp.
73
76
.
18.
Sidhu
,
G.
,
Bhole
,
S. D.
,
Chen
,
D. L.
, and
Essadiqi
,
E.
,
2011
, “
Reply to Comments on “An Improved Model for Bainite Formation at Isothermal Temperatures
,”
Scr. Mater.
,
65
(
4
), pp.
373
375
.
19.
20.
Garcia-Mateo
,
C.
,
Caballero
,
F. G.
, and
Bhadeshia
,
H. K. D. H.
,
2003
, “
Acceleration of Low-Temperature Bainite
,”
ISIJ Int.
,
43
, pp.
1821
1825
.
21.
Santofimia
,
M. J.
,
Caballero
,
F. G.
,
Capdevila
,
C.
,
Garcia-Mateo
,
C.
, and
de Andres
,
C. G.
,
2006
, “
New Model for the Overall Transformation Kinetics of Bainite. Part 2: Validation
,”
Mater. Trans.
,
47
(
10
), pp.
2473
2479
.
22.
Chang
,
L. C.
,
2004
, “
Microstructures and Reaction Kinetics of Bainite Transformation in Si-rich Steels
,”
Mater. Sci. Eng. A
,
368
, pp.
175
182
.
23.
Garcia-Mateo
,
C.
,
Caballero
,
F. G.
, and
Bhadeshia
,
H. K. D. H.
,
2005
, “
Mechanical Properties of Low-Temperature Bainite
,”
Mater. Sci. Forum
,
500-501
, pp.
495
502
.
24.
Caballero
,
F. G.
,
Bhadeshia
,
H. K. D. H.
,
Mawella
,
K. J. A.
,
Jones
,
D. G.
, and
Brown
,
P.
,
2002
, “
Very Strong Low Temperature Bainite
,”
Mater. Sci. Technol.
,
18
, pp.
279
284
.
You do not currently have access to this content.