Effects of electron–phonon coupling on damage accumulation in molecular dynamics simulations of irradiated nickel

Zarkadoula, Eva; Samolyuk, German D.

doi:10.1080/21663831.2019.1659435

Cited by 16 publications

(4 citation statements)

References 24 publications

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“…From the results presented in Section 3.1 it was evident that traditional MD simulations are not suitable to predict the number, shape, and size of defects induced from the PKA simulations even at low recoil energies, i.e., ∼ 50 keV. This finding is consistent with several other studies where radiation-induced damage has been investigated in SC and NC materials [26,32,[36][37][38]. The difference between MD and MD with electronic effects (including SRIM and 2T-MD) was noticeable in many aspects, including the transient and surviving number of FPs, in the number of defected atoms found in the simulations, and in the dislocation density.…”

Section: Discussionsupporting

confidence: 81%

A multiscale and multiphysics framework to simulate radiation damage in nano-crystalline materials

Hendy¹,

Ponga²

2022

Preprint

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This work presents a multiscale and multiphysics framework to investigate the radiation-induced damage in nano-crystalline materials. The framework combines two methodologies, including molecular dynamics simulations with electronic effects and long-term atomistic diffusion simulations in nano-crystalline materials. Using this framework, we investigated nano-crystalline materials' self-healing behavior under radiation events. We found that the number of defects generated in nano-crystals during the cascade simulations was less than in single crystals. This behavior was due to the fast absorption of interstitial atoms in the grain boundary network during the cascade simulations, while vacancies migrated to the boundaries in a much longer time scale than interstitial atoms. Thus, nano-crystalline materials showed a self-healing behavior where the number and size of the defects are drastically reduced with time. We found that the self-healing behavior of nano-crystalline materials is limited, and about 50% of vacancies survived. This effect resulted from clusters of vacancies' collective behavior, which are much more stable than individual vacancies.

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Section: Discussionsupporting

confidence: 81%

A multiscale and multiphysics framework to simulate radiation damage in nano-crystalline materials

Hendy¹,

Ponga²

2022

Preprint

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“…In other words, the inelastic energy deposited to electrons transfers to the atomic subsystem via el–ph interactions as the electronic subsystem cools down and temperatures are gradually equalized between the two subsystems. Considering the strength of the el–ph interactions and the temperature-dependent energy transfer in CSAs, the 2T-MD simulations , showed that the inelastic energy transfer to the atomic subsystem enhances defect recombination, thus lowering defect production. However, the 2T-MD model is somewhat limited by the quality of the interatomic potentials employed, the description of the electron-temperature dependence of the model parameters, and the use of simple Langevin dynamics for the electron bath.…”

Section: Non-equilibrium Defect Dynamics and Radiation Performancementioning

confidence: 99%

“…Research also suggests that, under certain conditions in some materials, ionization at a desired level can modify preexisting defects or even repair predamage states by promoting recovery processes. , The simulations of coupled electronic and nuclear energy dissipation and subsequent non-equilibrium processes suggest that ballistic recoil events can be facilitated by athermal annealing. Simulations of overlapping high-energy irradiation events suggest that local inelastic thermal spikes can anneal both pre-existing defects and concurrent defects from the ongoing displacement cascades, suppressing damage accumulation. This prediction has been validated with experiments.…”

Section: Non-equilibrium Defect Dynamics and Radiation Performancementioning

confidence: 99%

Tunable Chemical Disorder in Concentrated Alloys: Defect Physics and Radiation Performance

2021

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The development of advanced structural alloys with performance meeting the requirements of extreme environments in nuclear reactors has been long pursued. In the long history of alloy development, the search for metallic alloys with improved radiation tolerance or increased structural strength has relied on either incorporating alloying elements at low concentrations to synthesize so-called dilute alloys or incorporating nanoscale features to mitigate defects. In contrast to traditional approaches, recent success in synthesizing multicomponent concentrated solid-solution alloys (CSAs), including mediumentropy and high-entropy alloys, has vastly expanded the compositional space for new alloy discovery. Their wide variety of elemental diversity enables tunable chemical disorder and sets CSAs apart from traditional dilute alloys. The tunable electronic structure critically lowers the effectiveness of energy dissipation via the electronic subsystem. The tunable chemical complexity also modifies the scattering mechanisms in the atomic subsystem that control energy transport through phonons. The level of chemical disorder depends substantively on the specific alloying elements, rather than the number of alloying elements, as the disorder does not monotonically increase with a higher number of alloying elements. To go beyond our knowledge based on conventional alloys and take advantage of property enhancement by tuning chemical disorder, this review highlights synergistic effects involving valence electrons and atomic-level and nanoscale inhomogeneity in CSAs composed of multiple transition metals. Understanding of the energy dissipation pathways, deformation tolerance, and structural stability of CSAs can proceed by exploiting the equilibrium and non-equilibrium defect processes at the electronic and atomic levels, with or without microstructural inhomogeneities at multiple length scales. Knowledge of tunable chemical disorder in CSAs may advance the understanding of the substantial modifications in element-specific alloy properties that effectively mitigate radiation damage and control a material's response in extreme environments, as well as overcome strength−ductility trade-offs and provide overarching design strategies for structural alloys.

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“…However, MD lacks quantum-mechanical effects required to capture electronic and electron-phonon (e − ph) coupling effects. Even though MD is a classical technique, is it possible to partially incorporate electronic effects within semi-empirical approaches such as the so-called two-temperature model [38][39][40][41][42][43][44][45][46][47][48]. However, these models require several temperature-dependent material parameters that are challenging to compute and, in many cases, remain unavailable.…”

Section: Introductionmentioning

confidence: 99%

Electronic effects on the radiation damage in high-entropy alloys

Orhan¹,

Hendy²,

Ponga³

2022

Preprint

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High-entropy alloys (HEAs) are exceptional candidates for radiation-resistant materials due to their complex local chemical environment and slow defect migration. Despite commonly overlooked, electronic effects on defects evolution in radiation environments also play a crucial role by dissipating excess energy through electron-phonon coupling and electronic heat conduction during cascade events. We present a systematic study on electronic properties in random-solid solutions (RSS) in four and five principal elements HEAs and their effect on defect formation, clustering, and recombination. Electronic properties, including electron-phonon coupling factor (G e−ph ), the electronic specific heat (Ce), and the electronic thermal conductivity (κe), are computed within first-principles calculations. Using the two-temperature molecular dynamics simulations, we show that the electronphonon coupling factor and electronic specific heat play a critical role in Frenkel pairs formation. Specifically, the electron-phonon coupling factor quickly dissipates the kinetic energy during primary knock-on atom events via plasmon excitations and is subsequently dissipated via the free-electrons conduction. We show that these effects are more critical than the elastic distortion effects produced by the atomic mismatch. Of tremendous interest, we show that including lighter elements helps to increase G e−ph suggesting the possibility to improve radiation resistance in HEA through optimal composition.

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Effects of electron–phonon coupling on damage accumulation in molecular dynamics simulations of irradiated nickel

Cited by 16 publications

References 24 publications

A multiscale and multiphysics framework to simulate radiation damage in nano-crystalline materials

A multiscale and multiphysics framework to simulate radiation damage in nano-crystalline materials

Tunable Chemical Disorder in Concentrated Alloys: Defect Physics and Radiation Performance

Electronic effects on the radiation damage in high-entropy alloys

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