Object Kinetic Monte Carlo (OKMC): A Coarse-Grained Approach to Radiation Damage

Domain, Christophe; Becquart, Charlotte

doi:10.1007/978-3-319-42913-7_101-1

Cited by 5 publications

(6 citation statements)

References 61 publications

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“…The features of this model, conceptually described in section 2, are presented in what follows. Premises for such model were already proposed in previous work by Jansson et al [81] and Chiapetto et al [60][61], based on the object kinetic Monte Carlo (OKMC) method [82], but limiting the scope to simple model alloys (Fe-C, Fe-MnNi). Here we generalise those models, by adding all the required reactions for the mechanisms shown in Fig.…”

Section: Object Kinetic Monte Carlo Model For Nsrc Formationmentioning

confidence: 99%

The Dominating Mechanisms for the Formation of Solute-Rich Clusters in Steels under Irradiation

et al. 2019

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The formation of nano-sized, coherent, solute-rich clusters (NSRC) is known to be an important factor degrading the macroscopic properties of steels under irradiation. The mechanisms driving their formation are still debated. This work focuses on low-Cu reactor pressure vessel (RPV) steels, where solute species are generally not expected to precipitate. We rationalize the processes taking place at the nanometre scale under irradiation, relying on the latest theoretical and experimental evidence on atomic-level diffusion and transport processes. These are compiled in a new model, based on the object kinetic Monte Carlo (OKMC) technique. We evaluate the relevance of the underlying physical assumptions by applying the model to a large variety of irradiation experiments. Our model predictions are compared with new experimental data obtained with atom probe tomography and small angle neutron scattering, complemented with information from the literature. The results of this study reveal that the role of immobilized selfinterstitial atoms (SIA) loops dominates the nucleation process of NSRC.

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Section: Object Kinetic Monte Carlo Model For Nsrc Formationmentioning

confidence: 99%

The Dominating Mechanisms for the Formation of Solute-Rich Clusters in Steels under Irradiation

et al. 2019

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Section: Introductionmentioning

confidence: 99%

“…For a given point defect, emission rates must be specified independently for each sink that generates this kind of point defect by thermal activation. In the OKMC framework, the emission rate is usually governed by the binding energy of point defects to sinks [18,19,13]. However, there is some uncertainty as to the location where the point defect is emitted and the expression of the emission rate.…”

Section: Introductionmentioning

confidence: 99%

“…Contrary to atomistic kinetic Monte Carlo (AKMC), which handles all atomic sites of the system, in OKMC only defects are explicitly modeled. This framework is particularly convenient to model systems containing point defects, point defect clusters and dislocations under irradiation [12,13], especially at low temperature where point defect emission by sinks (dislocations, surfaces, point defect clusters, etc) can be neglected. Indeed the migration of irradiation-induced point defects in the matrix followed by their absorption by sinks is simulated faithfully, by performing the successive atomic jumps in the matrix depending on the local stress state [14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

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Enforcing local equilibrium of point defects near sinks in object kinetic Monte Carlo simulations

Jourdan¹

2021

Modelling Simul. Mater. Sci. Eng.

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A model for the emission of point defects by point defect sinks is proposed for object kinetic Monte Carlo simulations. Local equilibrium of point defects in the vicinity of sinks is ensured by construction, even if elastic interactions are taken into account for the diffusion of point defects. The emission of vacancies by dislocation segments is treated in detail and validated numerically. The model is then used to simulate the annealing of a vacancy Frank loop in a system containing surfaces. Results are in overall good agreement with analytical formulas, which are based on the approximation of instantaneous equilibration of the vacancy field during the loop evolution process. For small loops the shrinkage is so rapid that this quasi-static approximation is no more valid.

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“…Atomistic kinetic Monte Carlo (AKMC) methods monitor the positions of all atoms on the lattice [8][9][10] or over the space [11,12]. The variant method is commonly known as object kinetic Monte Carlo (OKMC), rather simulate diffusing entities like defect-solute clusters [13].…”

Section: Introductionmentioning

confidence: 99%

Absorption kinetics of vacancies by cavities in Aluminum: numerical characterization of sink strengths and first-passage statistics through Krylov subspace projection and eigenvalue deflation

Kaur,

Athènes,

Creuze

2021

Preprint

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Modeling the microstructural evolution of metal and alloys, specifically under irradiation, is essential to predict the aging properties of materials. Many models are based on a transition rate matrix describing the jump frequencies of defects and involve a master equation governing the time evolution of a state probability vector. Here, we present non-stochastic numerical techniques to characterize the motion of individual defects migrating over long distances prior to recombining or being absorbed by another defect, resorting to the theory of absorbing Markov chains. These important events are fully determined by their first-passage time distribution to distant locations, no-passage distribution ,and walker fluxes to the sinks. We show that these functions can be efficiently computed using a method combining Krylov subspace projection and eigenvalue deflation. For a model system describing the absorption of a vacancy by a cavity in aluminum, the use of a small Krylov subspace deflated by the unique eigenmode corresponding to the quasi-stationary distribution is sufficient to capture the kinetics of the defect absorption faithfully. This method can be used in kinetic Monte Carlo simulations to perform stochastic non-local moves or in cluster dynamics simulations to compute sink strengths.

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Object Kinetic Monte Carlo (OKMC): A Coarse-Grained Approach to Radiation Damage

Cited by 5 publications

References 61 publications

The Dominating Mechanisms for the Formation of Solute-Rich Clusters in Steels under Irradiation

The Dominating Mechanisms for the Formation of Solute-Rich Clusters in Steels under Irradiation

Enforcing local equilibrium of point defects near sinks in object kinetic Monte Carlo simulations

Absorption kinetics of vacancies by cavities in Aluminum: numerical characterization of sink strengths and first-passage statistics through Krylov subspace projection and eigenvalue deflation

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