Monte Carlo simulations of the decomposition of metastable solid solutions: Transient and steady-state nucleation kinetics

Soisson, Frédéric; Martin, G.

doi:10.1103/physrevb.62.203

Cited by 132 publications

(132 citation statements)

References 24 publications

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“…Albeit based on only two experimental data points, the sharp linear slope of the N v profile, (5.9 ± 1.7) · 10 21 m À3 s À1 , when AERae is a constant 0.75 nm may be considered an estimate of a quasi-stationary-state nucleation current, J Ã SS . The N v intercept on the abscissa is an estimate of the nucleation incubation time, s, of 540 ± 120 s; this behavior is similar to that described by classic nucleation theory [35][36][37]. In addition to quenched-in SRO domains, diffusional field overlap associated with chemical transients that extend 3 nm from c/c 0 interface (see Fig.…”

Section: Nucleation and Growth Of The Cmentioning

confidence: 55%

Temporal evolution of the nanostructure and phase compositions in a model Ni–Al–Cr alloy

et al. 2006

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In a Ni-5.2 Al-14.2 Cr at.% alloy with moderate solute supersaturations and a very small c/c 0 lattice parameter misfit, the nanostructural and compositional pathways during c 0 (L1 2 ) precipitation at 873 K are investigated using atom-probe tomography, conventional transmission electron microscopy, and hardness measurements. Nucleation of high number densities (N v > 10 23 m À3 ) of solute-rich precipitates (mean radius = AERae = 0.75 nm), with a critical nucleus composition of Ni-18.3 ± 0.9 Al-9.3 ± 0.7 Cr at.%, initiates between 0.0833 and 0.167 h. With increasing aging time (a) the solute concentrations decay in spheroidal precipitates (AERae < 10 nm); (b) the observed early-stage coalescence peaks at maximum N v in coincidence with the smallest interprecipitate spacing; and (c) the reaction enters a quasi-stationary regime where growth and coarsening operate concomitantly. During this quasi-stationary regime, the c (face-centered cubic)-matrix solute supersaturations decay with a power-law dependence of about À1/3, while the dependencies of AERae and N v are 0.29 ± 0.05 and À0.64 ± 0.06 at a coarsening rate slower than model predications. Coarsening models allow both equilibrium phase compositions to be determined from the compositional measurements. The observed early-stage coalescence is discussed in further detail.

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Section: Nucleation and Growth Of The Cmentioning

confidence: 55%

Temporal evolution of the nanostructure and phase compositions in a model Ni–Al–Cr alloy

et al. 2006

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“…On the other hand, classical descriptions of these different stages 3,4 are well established and the associated models are now widely used to understand experimental kinetics and to model technological processes 5,6,7,8 . Recently, classical nucleation theory has been shown to be in good agreement with more reliable atomic models by way of a direct comparison with kinetic Monte Carlo simulations 9,10,11,12,13 . These different studies included decomposition of a metastable solid solution for a demixing binary system on a surface 9 or in the bulk 11,12 and kinetics of electrodeposition on a surface 13 .…”

Section: Introductionmentioning

confidence: 94%

Nucleation ofAl3ZrandAl3
Clouet
¹
,
Nastar
²
,
Sigli³
2004
Phys. Rev. B
133
5
93
0
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Zr and Sc precipitate in aluminum alloys to form the compounds Al3Zr and Al3Sc which for low supersaturations of the solid solution have the L12 structure. The aim of the present study is to model at an atomic scale this kinetics of precipitation and to build a mesoscopic model based on classical nucleation theory so as to extend the field of supersaturations and annealing times that can be simulated. We use some ab-initio calculations and experimental data to fit an Ising model describing thermodynamics of the Al-Zr and Al-Sc systems. Kinetic behavior is described by means of an atom-vacancy exchange mechanism. This allows us to simulate with a kinetic Monte Carlo algorithm kinetics of precipitation of Al3Zr and Al3Sc. These kinetics are then used to test the classical nucleation theory. In this purpose, we deduce from our atomic model an isotropic interface free energy which is consistent with the one deduced from experimental kinetics and a nucleation free energy. We test different mean-field approximations (Bragg-Williams approximation as well as Cluster Variation Method) for these parameters. The classical nucleation theory is coherent with the kinetic Monte Carlo simulations only when CVM is used: it manages to reproduce the cluster size distribution in the metastable solid solution and its evolution as well as the steady-state nucleation rate. We also find that the capillary approximation used in the classical nucleation theory works surprisingly well when compared to a direct calculation of the free energy of formation for small L12 clusters.

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“…At the atomic scale, numerical methods based on statistical physics (Monte Carlo), give a precise description of precipitation (formation of clusters, growth and coarsening of precipitates [7,8]. These methods give a space Á/time description of precipitation but require precise knowledge of interaction potentials between the different atomic species.…”

Section: Introductionmentioning

confidence: 99%

Microscopic modelling of simultaneous two-phase precipitation: application to carbide precipitation in low-carbon steels

Perez

Deschamps

2003

Materials Science and Engineering: A

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A thermodynamically-based precipitation model, employing the classical nucleation and growth theories, has been adapted to deal with simultaneous precipitation of metastable and stable phases. This model gives an estimation of the precipitation kinetics (time evolution of radius and density of precipitates for both phases, as well as the evolution of solute fraction) in a wide range of temperature. Results were successfully compared with an experimental isothermal precipitation diagram (Time Á/TemperatureTransformation, TTT) from the literature for the precipitation of e carbide and Fe 3 C in low-carbon steels. #

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Monte Carlo simulations of the decomposition of metastable solid solutions: Transient and steady-state nucleation kinetics

Cited by 132 publications

References 24 publications

Temporal evolution of the nanostructure and phase compositions in a model Ni–Al–Cr alloy

Temporal evolution of the nanostructure and phase compositions in a model Ni–Al–Cr alloy

Nucleation ofAl3ZrandAl3
Clouet
¹
,
Nastar
²
,
Sigli³
2004
Phys. Rev. B
133
5
93
0
View full text Add to dashboard Cite

Microscopic modelling of simultaneous two-phase precipitation: application to carbide precipitation in low-carbon steels

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Monte Carlo simulations of the decomposition of metastable solid solutions: Transient and steady-state nucleation kinetics

Cited by 132 publications

References 24 publications

Temporal evolution of the nanostructure and phase compositions in a model Ni–Al–Cr alloy

Temporal evolution of the nanostructure and phase compositions in a model Ni–Al–Cr alloy

Nucleation ofAl3ZrandAl3Clouet1, Nastar2, Sigli3 2004Phys. Rev. B1335930View full textAdd to dashboardCite

Microscopic modelling of simultaneous two-phase precipitation: application to carbide precipitation in low-carbon steels

Contact Info

Product

Resources

About

Nucleation ofAl3ZrandAl3
Clouet
¹
,
Nastar
²
,
Sigli³
2004
Phys. Rev. B
133
5
93
0
View full text Add to dashboard Cite