The mechanism of bainite formation in steels

Abstract New microstructural evidence, together with a thermodynamic analysis, of the bainite reaction in steels are presented in support of a growth mechanism involving the propagation of displacive sub-units. The results are shown to be consistent with a displacive mechanism, rather than with one involving reconstructive growth. It is also possible to account not only for sympathetic nucleation, which is a characteristic of ferrous bainites, but also to explain the nature of the incomplete reaction phenomenon. Furthermore, the analysis suggests that much of the partitioning of carbon into the residual austenite occurs subsequent to transformation, rather than during the growth process. An explanation is also developed for the limited size of the displacive sub-units in terms of the friction stress associated with the motion of the transformation interface.

[1]  H. Aaronson,et al.  A re-examination of the thermodynamics of the proeutectoid ferrite transformation in Fe-C alloys , 1978 .

[2]  G. B. Olson,et al.  Reply to "On the equilibrium temperature in thermoelastic martensitic transformations" , 1977 .

[3]  J. Christian,et al.  The theory of transformations in metals and alloys , 2003 .

[4]  K. Ono,et al.  On the minimization of strain energy in the martensitic transformation of titanium , 1977 .

[5]  High-temperature high-resolution metallography , 1967 .

[6]  G. H. Geiger,et al.  Thermodynamics and solubility of carbon in ferrite and ferritic Fe-Mo alloys , 1976 .

[7]  Larry Kaufman,et al.  Thermodynamics and kinetics of martensitic transformations , 1958 .

[8]  H. Aaronson,et al.  Application of a theory of precipitate morphology to the massive transformation , 1968 .

[9]  H. Aaronson,et al.  A debate on the bainite reaction , 1972 .

[10]  G. B. Olson,et al.  Thermoelastic behavior in martensitic transformations , 1975 .

[11]  Alan Cottrell,et al.  Mechanical Properties of Matter , 1964 .

[12]  Morris Cohen,et al.  A nucleation model for martensitic transformations in iron-base alloys , 1972 .

[13]  G. B. Olson,et al.  A general mechanism of martensitic nucleation: Part II. FCC → BCC and other martensitic transformations , 1976 .

[14]  Larry Kaufman,et al.  The lattice stability of metals—III. Iron☆ , 1963 .

[15]  H. Aaronson,et al.  Thickening kinetics of proeutectoid ferrite plates in Fe-C alloys , 1975 .

[16]  H. Knapp,et al.  Mechanik und kinetik der diffusionslosen martensitbildung , 1956 .

[17]  Morris Cohen,et al.  Operational nucleation in martensitic transformations , 1972 .

[18]  H. Aaronson,et al.  The interfacial structure of the broad faces of ferrite plates , 1979 .

[19]  H. Bhadeshia,et al.  The bainite transformation in a silicon steel , 1979 .

[20]  G. B. Olson,et al.  A general mechanism of martensitic nucleation: Part I. General concepts and the FCC → HCP transformation , 1976 .

[21]  Morris Cohen,et al.  A general mechanism of martensitic nucleation: Part III. Kinetics of martensitic nucleation , 1976 .

[22]  H. Aaronson,et al.  A computer modeling study of partially coherent f.c.c.:b.c.c. boundaries , 1979 .