Primary Radiation Damage Formation

Stoller, R.E.

doi:10.1016/b978-0-08-056033-5.00027-6

Cited by 148 publications

(127 citation statements)

References 122 publications

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“…Fikkar et al reported simulations for 10 keV at 523 K and 50 keV at 10 K [4]. On the other hand, a comprehensive set of cascade simulations was reported for Fe [17] that covered 100 K, 600 K and 900 K (which is 0.5 melting temperature of Fe). However, defect clustering in Fe is much less compared to that in W hence any temperature effect on clustering is not readily discernable.…”

Section: Discussionmentioning

confidence: 99%

Displacement cascades and defects annealing in tungsten, Part I: Defect database from molecular dynamics simulations

Setyawan

Nandipati

Roche

et al. 2015

Journal of Nuclear Materials

110

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Molecular dynamics simulations have been used to generate a comprehensive database of surviving defects due to displacement cascades in bulk tungsten. Twenty one data points of primary knock-on atom (PKA) energies ranging from 100 eV (sub-threshold energy) to 100 keV (∼780×E d , where E d is the average displacement threshold energy) have been completed at 300 K, 1025 K and 2050 K. Within this range of PKA energies, two regimes of power-law energy-dependence of the defect production are observed. A distinct power-law exponent characterizes the number of Frenkel pairs produced within each regime. The two regimes intersect at a transition energy which occurs at approximately 250×E d . The transition energy also marks the onset of the formation of large self-interstitial atom (SIAs) clusters (size 14 or more). The observed defect clustering behavior is asymmetric, with SIA clustering increasing with temperature, while the vacancy clustering decreases. This asymmetry increases with temperature such that at 2050 K (∼0.5T m ) practically no large vacancy clusters are formed, meanwhile large SIA clusters appear in all simulations. The implication of such asymmetry on the long-term defect survival and damage accumulation is discussed. In addition, rare <100>{110} SIA loops are observed.

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Section: Discussionmentioning

confidence: 99%

Displacement cascades and defects annealing in tungsten, Part I: Defect database from molecular dynamics simulations

Setyawan

Nandipati

Roche

et al. 2015

Journal of Nuclear Materials

110

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“…Fe-Ni alloys, we first summarize relevant information obtained in previous extensive modeling of high-energy displacement cascades [24][25][26][27][28] and defect cluster properties [21,25,[30][31][32] in Fe:…”

Section: Discussionmentioning

confidence: 99%

The role of nickel in radiation damage of ferritic alloys

et al. 2015

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According to the modern theory damage evolution under neutron irradiation depends on the fraction of self-interstitial atoms (SIAs) produced in the form of one-dimensionally glissile clusters. These clusters, having a low interaction cross-section with other defects, are absorbed mainly by grain boundaries and dislocations creating the so-called production bias. It is known empirically that addition of certain alloying elements influence many radiation effects, including swelling, however the mechanisms are unknown in many cases. In this paper we report the results of an extensive multi-technique atomistic level modeling study of SIA clusters mobility in bcc Fe-Ni alloys. We have found that Ni interacts strongly with the periphery of clusters affecting their mobility. The total effect is defined by the number of Ni atoms interacting with the cluster at the same time and can be significant even in low-Ni alloys. Thus 1nm (37SIAs) cluster is practically immobile at T<500K in the Fe-0.8at.% Ni alloy. Increasing cluster size and Ni content enhance cluster immobilization. This effect should have quite broad consequences in void swelling, matrix damage accumulation and radiation induced hardening and the results obtained help to better understand and predict the effects of radiation in Fe-Ni ferritic alloys.

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“…In the case of neutron and ion irradiation, MD can be used to predict the evolution of ballistic collisions that occur, and the nature of primary damage produced by the high-energy recoils. 10 It can also shed light on a plethora of mechanisms that take place as the kinetic energy of the recoil is dissipated: fractal replacement sequences, 11 supersonic shockwaves, 12 sonic waves, 12 the formation of liquid-like regions and their recrystallization or amorphization. 13 The aim of many MD studies is to describe the mechanisms and general trends, not to make precise predictions.…”

Section: Introductionmentioning

confidence: 99%

Atomistic material behavior at extreme pressures

2016

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Computer simulations are routinely performed to model the response of materials to extreme environments, such as neutron (or ion) irradiation. The latter involves high-energy collisions from which a recoiling atom creates a so-called atomic displacement cascade. These cascades involve coordinated motion of atoms in the form of supersonic shockwaves. These shockwaves are characterized by local atomic pressures 415 GPa and interatomic distances o 2 Å. Similar pressures and interatomic distances are observed in other extreme environment, including short-pulse laser ablation, high-impact ballistic collisions and diamond anvil cells. Displacement cascade simulations using four different force fields, with initial kinetic energies ranging from 1 to 40 keV, show that there is a direct relationship between these high-pressure states and stable defect production. An important shortcoming in the modeling of interatomic interactions at these short distances, which in turn determines final defect production, is brought to light. INTRODUCTIONAs scientific computing becomes evermore ubiquitous, it is common practice to simulate the effect of extreme environments on materials using molecular dynamics (MD). The ability to capture a material's response atom by atom has helped understand and complement experiments. For example, thanks to MD, the thermodynamic processes that control the production of nanoparticules after pulsed laser irradiation are relatively well understood. 1 Notably, such computational results explain the Newton rings observed in experiments. 2,3 MD also led to a better understanding of the nature of the destructive shockwaves that follow high-energy impact 4-6 and the behavior of materials at high pressure in diamond anvil cells. 7-9 It can predict many properties, such as the Hugoniot, dislocation densities after impact and fracture behavior. In the case of neutron and ion irradiation, MD can be used to predict the evolution of ballistic collisions that occur, and the nature of primary damage produced by the high-energy recoils. 10 It can also shed light on a plethora of mechanisms that take place as the kinetic energy of the recoil is dissipated: fractal replacement sequences, 11 supersonic shockwaves, 12 sonic waves, 12 the formation of liquid-like regions and their recrystallization or amorphization. 13 The aim of many MD studies is to describe the mechanisms and general trends, not to make precise predictions. However, as the scientific community moves towards materials by design and systematic computational characterization, increasingly precise and accurate models are required. In the case of atomistic modeling, methods that explicitly account for electronic structure, such as ab initio MD, are considered the gold standard. Unfortunately, their use has very serious limitations, given their high computational cost. In particular, the simulation of high-energy perturbations such as those involved in neutron or ion irradiation requires large simulation cells: a few hundred thousands of atoms at a minimum...

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Primary Radiation Damage Formation

Cited by 148 publications

References 122 publications

Displacement cascades and defects annealing in tungsten, Part I: Defect database from molecular dynamics simulations

Displacement cascades and defects annealing in tungsten, Part I: Defect database from molecular dynamics simulations

The role of nickel in radiation damage of ferritic alloys

Atomistic material behavior at extreme pressures

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