Transmission Electron Microscopy and Nano‐Precipitation

Épicier, Thierry

doi:10.1002/adem.200600185

Cited by 7 publications

(5 citation statements)

References 24 publications

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“…Further TEM observations on thin foils after 30 min at 650 C confirm unambiguously the homogenous and heterogeneous (i.e. on dislocations) precipitation of nitrides and carbonitrides, respectively [21]. A consistent thermodynamic modelling of the proposed scenario will be developed in the following section.…”

Section: Resultsmentioning

confidence: 62%

Precipitation of niobium carbonitrides in ferrite: chemical composition measurements and thermodynamic modelling

Perez

Courtois

Acevedo

et al. 2007

Philosophical Magazine Letters

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High-resolution transmission electron microscopy and electron-energy loss spectroscopy have been used to characterize the structure and chemical composition of niobium carbonitrides in the ferrite of a Fe-Nb-C-N model alloy at different precipitation stages. Experiments seem to indicate the coexistence of two types of precipitates: pure niobium nitrides and mixed substoichiometric niobium carbonitrides. In order to understand the chemical composition of these precipitates, a thermodynamic formalism has been developed to evaluate the nucleation and growth rates (classical nucleation theory) and the chemical composition of nuclei and existing precipitates. A model based on the numerical solution of thermodynamic and kinetic equations is used to compute the evolution of the precipitate size distribution at a given temperature. The predicted compositions are in very good agreement with experimental results.

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Section: Resultsmentioning

confidence: 62%

Precipitation of niobium carbonitrides in ferrite: chemical composition measurements and thermodynamic modelling

Perez

Courtois

Acevedo

et al. 2007

Philosophical Magazine Letters

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“…16 Enrichment with solute atoms and growth follow, whereby more and more Al atoms in the nanocluster are replaced with Mg and Si atoms and whereby the nanoclusters grow from spheres into needles. [4][5][6][16][17][18] The first evidence of ordering is the skeleton of Si-Si columns that is formed in the initial ␤Љ phase 6 and occurs approximately at the composition Mg 2 Si 2 Al 7 . Such Si 2 columns are indicated in Fig.…”

Section: B Precipitation In Al-mg-si Alloysmentioning

confidence: 99%

Concurrent substitutional and displacive phase transformations in Al-Mg-Si nanoclusters

et al. 2007

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Al-Mg-Si nanoclusters embedded in aluminum transform through a delicate interplay of two characteristically distinct phase transformations: a diffusion-controlled substitutional transformation associated with solute enrichment and a swift displacive transformation involving collective shifts of columns of atoms once a critical enrichment has been reached. Through first-principles calculations, we show that these transformations are inseparable. Moreover, we show in atomistic detail how precipitates that are not superstructures of the matrix form from a supersaturated solid solution.

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“…Refs. [3,4]), is a promising strategy to maximize precipitation strengthening with minimizing the addition of alloying elements. This is one of the main reasons why nano-precipitation has http recently received much attention in the production of highstrength steels.…”

Section: Introductionmentioning

confidence: 99%

Stress–strain behavior of ferrite and bainite with nano-precipitation in low carbon steels

et al. 2015

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We systematically investigate stress-strain behavior of ferrite and bainite with nano-sized vanadium carbides in low carbon steels; the ferrite samples were obtained through austenite/ferrite transformation accompanied with interphase precipitation and the bainite samples were via austenite/bainite transformation with subsequent aging. The stress-strain curves of both samples share several common features, i.e. high yield stress, relatively low work hardening and sufficient tensile elongation. Strengthening contributions from solute atoms, grain boundaries, dislocations and precipitates are calculated based on the structural parameters, and the calculation result is compared with the experimentally-obtained yield stress. The contributions from solute atoms and grain boundaries are simply additive, whereas those from dislocations and precipitates should be treated by taking the square root of the sum of the squares of two values. Nano-sized carbides may act as sites for dislocation multiplication in the early stage of deformation, while they may enhance dislocation annihilation in the later stage of deformation. Such enhanced dynamic recovery might be the reason for a relatively large elongation in both ferrite and bainite samples.

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Transmission Electron Microscopy and Nano‐Precipitation

Cited by 7 publications

References 24 publications

Precipitation of niobium carbonitrides in ferrite: chemical composition measurements and thermodynamic modelling

Precipitation of niobium carbonitrides in ferrite: chemical composition measurements and thermodynamic modelling

Concurrent substitutional and displacive phase transformations in Al-Mg-Si nanoclusters

Stress–strain behavior of ferrite and bainite with nano-precipitation in low carbon steels

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