A new model for precipitation at moving interphase boundaries

Todd, J. A.; Li, P.; Copley, S. M.

doi:10.1007/bf02645038

Cited by 23 publications

(8 citation statements)

References 16 publications

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“…Todd et al [6][7][8] proposed the prediction model based on the solute-drag nucleation model. In their model, the intersheet spacing is determined by the width of diffusion layer of V. On the other hand, the model proposed by Rios 9) is based on the ledge mechanism.…”

Section: Validity Of the Existing Modelmentioning

confidence: 99%

“…[6][7][8][9][10][11][12][13] In the model proposed by Todd et al, [6][7][8] the intersheet spacing of interphase boundary precipitation is determined by the diffusion profile of the solute concentration in the front of the growing interphase boundary of a "pseudophase", as which they defined the sheet region. Contrarily Rios 9) considered the intersheet spacing in vanadium steels is decided by the balance between vanadium flux entering into "vanadium diffusion zone" through the austenite/ferrite interface at the front of ledge and vanadium amount included in interphase precipitates which was formed at the neighbor of vanadium diffusion zone.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Ferrite Growth Rate on Interphase Boundary Precipitation in V Microalloyed Steels

et al. 2012

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The interphase boundary precipitation behavior of vanadium carbide during isothermal ferrite transformation, which is the important phenomena for the hot forged medium carbon steels, was investigated and modeled. It was found that the intersheet spacing of interphase boundary precipitation of VC decreased with a decrease of ferrite growth rate during isothermal transformation. As a major factor affecting such an interphase boundary precipitation behavior, it was deduced that the vanadium segregation on migrating austenite/ferrite interphse boundary is quite important to understand the repeated precipitation of VC. In numerical simulation of VC precipitation, the influence of the vanadium concentration on the precipitation behavior at austenite/ferrite interface during isothermal transformation was examined based on a time-dependent solute drag model incorporated with parabolic growth rate. It was found that the change of the intersheet spacing during ferrite growth can be simulated by the newly proposed model for interphase boundary precipitation of alloy carbide.KEY WORDS: interphase boundary precipitation; vanadium carbide; medium carbon steel.

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Section: Validity Of the Existing Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effects of Ferrite Growth Rate on Interphase Boundary Precipitation in V Microalloyed Steels

et al. 2012

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“…Interphase boundary precipitation is the transformation processed by the nucleation of the carbide on the γ /α growing interphase boundaries during ferrite formation, leading to high strengthening in alloy steels bearing V, Ti, and Nb. [12][13][14] To enhance the particle dispersion strengthening by nanosized alloy carbide, the precipitation behavior, especially the size, density, intersheet spacing, and thermal stability of alloy carbides has been investigated. 2,3,[5][6][7][8][12][13][14][15][16][17] Although the discussion on the mechanism of interphase boundary precipitation continues, the nature is repeated precipitation of carbide at the growing interface accompanied by the diffusion of alloy elements.…”

Section: Formation Mechanism Of Degenerate Pearlite Bymentioning

confidence: 99%

“…[12][13][14] To enhance the particle dispersion strengthening by nanosized alloy carbide, the precipitation behavior, especially the size, density, intersheet spacing, and thermal stability of alloy carbides has been investigated. 2,3,[5][6][7][8][12][13][14][15][16][17] Although the discussion on the mechanism of interphase boundary precipitation continues, the nature is repeated precipitation of carbide at the growing interface accompanied by the diffusion of alloy elements. That is, when the growth rate of ferrite is higher than that of carbide, non-cooperative growth between them might occur.…”

Section: Formation Mechanism Of Degenerate Pearlite Bymentioning

confidence: 99%

Effect of Carbon Concentration in Austenite on Cementite Morphology in Pearlite

Yasuda

Nakada

2021

ISIJ Int.

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To understand the formation mechanism of degenerate pearlite, the effect of carbon concentration on the cementite morphology in pearlite was investigated in hypoeutectoid C-Mn steels with fully pearlite and ferrite-pearlite duplex microstructures. The carbon concentration in untransformed austenite was enriched by the precipitation of proeutectoid ferrite during isothermal holding after austenitization and could be controlled based on local equilibrium theory. Consequently, it was found that the morphology of cementite in the pearlite formed by the decomposition of the untransformed austenite continuously changed from lamellar to fine rod or spherical shapes by decreasing the carbon concentration. The critical carbon concentration for the cementite morphology transition was evaluated at approximately 0.42 mass% at 773 K. The ferrite growth rate increases with decreasing carbon concentration in austenite, which leads to non-cooperative growth between ferrite and cementite in the eutectoid reaction, resulting in the formation of degenerate pearlite. The critical carbon concentration and its temperature dependence for lamellar and degenerate pearlite transition can be estimated by a simple competition model of growth kinetics between ferrite and pearlite formations. In addition, it was found that the softening of degenerate pearlite during annealing after the decomposition was much faster than that of lamellar pearlite because the constrictions of cementite lamella do not exist for Ostwald ripening.

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“…A number of analytical models have been previously developed [12,13,14,15,16,17,18,19,20], which have primarily focussed upon the prediction of spacing between 45 sheets of interphase carbides. Although, this enables some guidance of the the processing windows for hot-rolled automotive sheets a more holistic modelling approach with the capability to simultaneously predict the morphology and nature of interphase carbide precipitates [21] as well as the inter-sheet spacing is required to truly optimise processing.…”

Section: Modelling Of Interphase Precipitationmentioning

confidence: 99%

A phase-field model for interphase precipitation in V-micro-alloyed structural steels

Rahnama

Clark

Janík

et al. 2017

Computational Materials Science

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A multi-component phase field model was developed based on CALPHAD method and directly coupled with the CALPHAD thermodynamic database using a four-sublattice model. Interphase carbide precipitation at the γ/α interface is simulated and the predictions are tested against reported experimental results for a medium carbon, vanadium micro-alloyed steel during an isothermal γ → α + M C transformation at 973 K. The model is found to be able to accurately predict: interphase precipitate composition, morphology and size of the precipitates. Furthermore, the tip-to-tip pairing of interphase precipitates in γ/α interphase boundaries is elucidated and found to be attributable to the minimisation of interfacial energy.

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A new model for precipitation at moving interphase boundaries

Cited by 23 publications

References 16 publications

Effects of Ferrite Growth Rate on Interphase Boundary Precipitation in V Microalloyed Steels

Effects of Ferrite Growth Rate on Interphase Boundary Precipitation in V Microalloyed Steels

Effect of Carbon Concentration in Austenite on Cementite Morphology in Pearlite

A phase-field model for interphase precipitation in V-micro-alloyed structural steels

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