Cluster dynamics modeling of the effect of high dose irradiation and helium on the microstructure of austenitic stainless steels

Brimbal, Daniel; Fournier, Lionel; Barbu, A.

doi:10.1016/j.jnucmat.2015.11.007

Cited by 28 publications

(19 citation statements)

References 52 publications

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“…Since so few a/2<111> loops were observed, all results reported are from a<100> loops only and a bias input range between 1.01-1.04 was deemed to be reasonable. Furthermore, rate theory biases are lower than all first principles calculations and nearly all analytic solutions for bias, in both ferritic and austenitic steels [38][39][40][41][42][43].…”

Section: Dislocationsmentioning

confidence: 82%

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The co-evolution of microstructure features in self-ion irradiated HT9 at very high damage levels

Getto

VanCoevering

Was

2017

Journal of Nuclear Materials

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Understanding the void swelling and phase evolution of reactor structural materials at very high damage levels is essential to maintaining safety and longevity of components in Gen IV fast reactors. A combination of ion irradiation and modeling was utilized to understand the microstructure evolution of ferritic-martensitic alloy HT9 at high dpa. Self-ion irradiation experiments were performed on alloy HT9to determine the co-evolution of voids, dislocations and precipitates up to 650 dpa at 460°C. Modeling of microstructure evolution was conducted using the modified Radiation Induced Microstructure Evolution (RIME) model, which utilizes a mean field rate theory approach with grouped cluster dynamics.Irradiations were performed with 5 MeV raster-scanned Fe 2+ ions on samples pre-implanted with 10 atom parts per million He. The swelling, dislocation and precipitate evolution at very high dpa was determined using Analytical Electron Microscopy in Scanning Transmission Electron Microscopy (STEM) mode.Experimental results were then interpreted using the RIME model. A microstructure consisting only of dislocations and voids is insufficient to account for the swelling evolution observed experimentally at high damage levels in a complicated microstructure such as irradiated alloy HT9. G phase was found to have a minimal effect on either void or dislocation evolution. M 2 X plays two roles; a variable biased sink for defects, and as a vehicle for removal of carbon from solution, thus promoting void growth. When accounting for all microstructure interactions, swelling at high damage levels is a dynamic process that continues to respond to other changes in the microstructure as long as they occur.

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Section: Dislocationsmentioning

confidence: 82%

“…As a result, a range of values from 1.01-1.3 was found in the literature for BCC iron/iron alloys [38][39][40][41][42][43], with a majority varying from 1.01-1.05. Furthermore, Chang et al found dislocation bias for interstitials that ranged from negligible (nearly 1.0) for screw type dislocations up to 1.05 for edge <111> dislocations.…”

Section: Dislocationsmentioning

confidence: 89%

The co-evolution of microstructure features in self-ion irradiated HT9 at very high damage levels

Getto

VanCoevering

Was

2017

Journal of Nuclear Materials

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“…In UMo fuels, 235 U fission generates high-energy neutrons and fission fragments that cause radiation damage. A cluster dynamics model (Mansur, 1994;Kohnert and Wirth, 2015;Brimbal et al, 2016;Kohnert et al, 2018) is used to describe the evolution of vacancies, interstitials, and their clusters in polycrystalline structures with distributed gas bubbles. The generation of gas atoms, vacancies, and interstitials are calculated with the fission product yields and the kinetic energy distribution of the fission products.…”

Section: Phase-field Model Of Gas Bubble Evolution In Polycrystalline Umo Under Elastic-plastic Deformationmentioning

confidence: 99%

Gas Bubble Evolution in Polycrystalline UMo Fuels Under Elastic-Plastic Deformation: A Phase-Field Model With Crystal-Plasticity

Beeler

2021

Front. Mater.

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In monolithic UMo fuels, the interaction between the Al cladding and large gas bubble volumetric swelling causes both elastic-plastic and creep deformation. In this work, a phase-field model of gas bubble evolution in polycrystalline UMo under elastic-plastic deformation was developed for studying the dynamic interaction between evolving gas bubble/voids and deformation. A crystal plasticity model, which assumes that the plastic strain rate is proportional to resolved shear stresses of dislocation slip systems on their slip planes, was used to describe plastic deformation in polycrystalline UMo. Xe diffusion and gas bubble evolution are driven by the minimization of chemical and deformation energies in the phase-field model, while evolving gas bubble structure was used to update the mechanical properties in the crystal plasticity model. With the developed model, we simulated the effect of gas bubble structures (different volume fractions and internal gas pressures) on stress-strain curves and the effect of local stresses on gas bubble evolution. The results show that 1) the effective Young’s modulus and yield stress decrease with the increase of gas bubble volume fraction; 2) the hardening coefficient increases with the increase of gas bubble volume fraction, especially for gas bubbles with higher internal pressure; and 3) the pressure dependence of Xe thermodynamic and kinetic properties in addition to the local stress state determine gas bubble growth or shrinkage. The simulated results can serve as a guide to improve material property models for macroscale fuel performance modeling.

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“…This intersection can generate enough fluctuation to nucleate an un-faulting Shockley partial which glides in the Frank loop plane and transforms the Frank loop into a perfect loop [34]. The aforementioned production and annihilation processes can be introduced as source and sink terms, respectively, into a model of the evolution of network dislocation density, r. This model, based on references [28,29], gives the evolution of network dislocation density as follows,…”

Section: Cluster Dynamics: Governing Equationsmentioning

confidence: 99%

“…Interested readers are encouraged to refer to references [28,29] for more details about network dislocation evolution model.…”

Section: Cluster Dynamics: Governing Equationsmentioning

confidence: 99%

Integrated modeling of second phase precipitation in cold-worked 316 stainless steels under irradiation

et al. 2017

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The current work combines the Cluster Dynamics (CD) technique and CALPHAD-based precipitation modeling to address the second phase precipitation in cold-worked (CW) 316 stainless steels (SS) under irradiation at 300-400 °C. CD provides the radiation enhanced diffusion and dislocation evolution as inputs for the precipitation model. The CALPHAD-based precipitation model treats the nucleation, growth and coarsening of precipitation processes based on classical nucleation theory and evolution equations, and simulates the composition, size and size distribution of precipitate phases. We benchmark the model against available experimental data at fast reactor conditions (9.4 × 10 -7 dpa/s and 390 °C) and then use the model to predict the phase instability of CW 316 SS under light water reactor (LWR) extended life conditions (7 × 10 -8 dpa/s and 275 °C). The model accurately predicts the γꞌ (Ni 3 Si) precipitation evolution under fast reactor conditions and that the formation of this phase is dominated by radiation enhanced segregation. The model also predicts a carbide volume fraction that agrees well with available experimental data from a PWR reactor but is much higher than the volume fraction observed in fast reactors. We propose that radiation enhanced dissolution and/or carbon depletion at sinks that occurs at high flux could be the main sources of this inconsistency. The integrated model predicts ~1.2% volume fraction for carbide and ~3.0% volume fraction for γꞌ for typical CW 316 SS (with 0.054 wt.% carbon) under LWR extended life conditions. This work provides valuable insights into the magnitudes and mechanisms of precipitation in irradiated CW 316 SS for nuclear applications.

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Cluster dynamics modeling of the effect of high dose irradiation and helium on the microstructure of austenitic stainless steels

Cited by 28 publications

References 52 publications

The co-evolution of microstructure features in self-ion irradiated HT9 at very high damage levels

The co-evolution of microstructure features in self-ion irradiated HT9 at very high damage levels

Gas Bubble Evolution in Polycrystalline UMo Fuels Under Elastic-Plastic Deformation: A Phase-Field Model With Crystal-Plasticity

Integrated modeling of second phase precipitation in cold-worked 316 stainless steels under irradiation

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