A reappraisal of kinetic data for the growth of pearlite in high purity Fe-C eutectoid alloys

Whiting, Mark J.

doi:10.1016/s1359-6462(00)00464-4

Cited by 19 publications

(13 citation statements)

References 16 publications

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“…We find that for all models of the type considered, the growth of colonies via the volume carbon diffusion mechanism is unstable, and the steady-state growth can be realized only via the interfacial diffusion of carbon. It agrees with the similar conclusion of a recent empirical analysis [7].…”

Section: Introductionsupporting

confidence: 93%

“…Here α and β are Cartesian indices, D αβ is the diffusivity tensor, while function δF/δc = δF/δc(r) (having the meaning of the local chemical potential of carbon atoms) is the variational derivative of functional (2) with respect to local concentration c(r): δF/δc(r) = ∂f (c, η, ζ)/∂c − 2(g cc ∆c + g cη ∆η + g cζ ∆ζ) (16) where ∆ = ∇ 2 is the Laplace operator. In describing the diffusivity D we take into account not only the usual volume diffusivity D v but also possible surface contributions D s which can be important due to the enhanced diffusion of carbon along incoherent interphase boundaries [2,7,17]. Therefore, the diffusivity includes both volume and interfacial terms and is written as follows:…”

Section: B Kinetic Modelmentioning

confidence: 99%

“…However, both the experimental information and the theoretical understanding of these phenomena seem to remain to be rather limited. Most of experimental data used in the literature (see e. g. [1,2], [7]- [10]) were obtained long ago and by not modern methods, and many important phenomena, in particular, formation of pearlite colonies, seem to be insufficiently studied. In theoretical treatments, only steady-state growth of colonies is usually considered, basing mainly on the equilibrium thermodynamics ideas [3]- [5], but with no attempts of microscopic treatments of kinetic processes.…”

Section: Introductionmentioning

confidence: 99%

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Experimental and theoretical study of the formation and growth of pearlite colonies in eutectoid steels

Vaks

Stroev

Urtsev

et al. 2011

J. Exp. Theor. Phys.

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We describe our optical and electron-microscopy observations of pearlite structures in eutectoid steels which seem to imply that the mechanisms of formation of pearlite colonies in these steels differ from those observed earlier for non-eutectoid steels. A simple theoretical model to study kinetics of pearlite transformations is suggested. Simulations of growth of pearlite colonies based on this model reveal that for the volume carbon diffusion mechanism usually-supposed such growth is always unstable, and the steady-state growth can be realized only via the interfacial carbon diffusion mechanism. A model of formation of pearlite colonies based on the assumption of a strong enhancement of carbon diffusion near grain boundaries is also suggested. The model can be applicable to the plastically deformed steels, and the results of simulations based on this model qualitatively agree with some microstructural features of formation of pearlite colonies observed in such steels.

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Section: Introductionsupporting

confidence: 93%

Section: B Kinetic Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experimental and theoretical study of the formation and growth of pearlite colonies in eutectoid steels

Vaks

Stroev

Urtsev

et al. 2011

J. Exp. Theor. Phys.

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“…It is well known that the boundary diffusion of elements is much faster than the volume diffusion [36]. Cold deformation can produce seriously distorted ferrite grains containing either dense dislocations or dislocation cells [37].…”

Section: Cementite Particles Sizementioning

confidence: 99%

Tailoring Strength and Ductility of a Cr-Containing High Carbon Steel by Cold-Working and Annealing

Wang

Shen

Liu³

et al. 2019

Materials

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SEM, TEM characterizations, in combination with tensile tests, provided an intriguing observation that ultra-high-strength and good ductility could be achieved simultaneously by changing the ratio of large and small precipitates in high-carbon steel (1.0C-1.5Cr-0.31Mn-0.20Si, wt %). The high yield strength of 670 MPa, tensile-stress of 740 MPa, and good ductility (elongation of 26%) were obtained by adopting spheroidization annealing, cold rolling, recrystallization annealing, and cold drawing. This led to nanosized precipitates with a large ratio of big size to the small size of 0.28, promoting high dislocation storage of 1.39 × 1014 m−2. In addition, the finite element (FE) method was used to simulate the cold-rolling process, and the largest stress and strain were 830 MPa and 0.6 at a depth of 3 mm after the fourth pass of the 0.10C-1.50Cr steel, respectively. The stress and strain accumulation in the top layer was potentially caused by severe plastic deformation, as well as attrition rendered by the rollers. This explained the emergence of dense low-angle grain boundaries in the region close to the surface of the cold rolled steel.

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“…10,11) Recently, a ledge mechanism was advocated as an alternative model. [12][13][14] According to this model, the rate-determining process is the interface diffusion of carbon atoms. With these models in mind, plausible arguments are made as follows.…”

Section: Mechanism Of the Field Gradient Effectmentioning

confidence: 99%

Influence of Magnetic-Field Gradients on the Pearlitic Transformation in Steels

Shimotomai

2003

Mater. Trans.

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Carbon steels of 1 wt%C were subjected to the pearlitic transformation in a helium-free superconducting magnet in search for some influence of the magnetic field gradient on the transformation. It was found that steels containing Mn and/or Cr got hardened proportional to the field gradient present during the transformation at 560 C. The hardness increase amounted to 8% at the field gradient of 50 T/m, the magnitude depending on the steel composition. It was confirmed that the hardening was irrelevant to the sign of the gradient and absent for homogeneous magnetic fields. This kind of hardening was not observed for a binary Fe-C alloy. The hardened specimens exhibited age hardening by annealing at 150 $ 200 C. TEM observations and internal friction measurements suggested that supersaturated carbon atoms were introduced into the ferrite layers of the pearlite phase under the field gradient. Such extra carbon atoms should have combined with Mn and/or Cr atoms during the quenching to impurity complexes responsible for the solution and age hardenings. Plausible arguments are made on the action of magnetic field gradients for the introduction of supersaturated carbon atoms in the pearlitic ferrite.

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A reappraisal of kinetic data for the growth of pearlite in high purity Fe-C eutectoid alloys

Cited by 19 publications

References 16 publications

Experimental and theoretical study of the formation and growth of pearlite colonies in eutectoid steels

Experimental and theoretical study of the formation and growth of pearlite colonies in eutectoid steels

Tailoring Strength and Ductility of a Cr-Containing High Carbon Steel by Cold-Working and Annealing

Influence of Magnetic-Field Gradients on the Pearlitic Transformation in Steels

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