Shock Waves in Polycrystalline Iron

Kadau, Kai; Germann, Timothy C.; Lomdahl, Peter S.; Albers, R. C.; Wark, J. S.; Higginbotham, Andrew; Holian, Brad Lee

doi:10.1103/physrevlett.98.135701

Cited by 159 publications

(133 citation statements)

References 21 publications

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“…However, the pressures involved are comparable to those of other high-energy processes, such as laser ablation, high-energy impact and diamond anvil cells. [1][2][3][4][5][6][7][8][9] This suggests that further work is needed to improve the description of atomic force fields at short interatomic distances in order for future computational work using these force fields to be as quantitatively accurate as possible. Some efforts have previously been made in this direction.…”

Section: Discussionmentioning

confidence: 99%

“…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][5][6] and the behavior of materials at high pressure in diamond anvil cells. [7][8][9] It can predict many properties, such as the Hugoniot, dislocation densities after impact and fracture behavior.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Atomistic material behavior at extreme pressures

2016

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“…Проводятся экспериментальные исследования и моделирование как специально создаваемых композитных и малоплотных материалов, так и естественных поликристалли-ческих образцов. Исследования, главным образом, сконцентрированы на определении интегральных оп-тических, электрических, тепловых, акустических, прочностных характеристик как самих материалов [3,4], так и изделий из них, а также на соотношении наблюдаемых эффектов с параметрами диодной плаз-мы, летящей с поверхности исследуемого образца. Отличительной чертой данного проекта будет визуа-лизация распространения возмущений в гетерогенной среде, которая позволит изучать различные режи-мы радиационного воздействия на мишени и мелкие, но важные пространственные особенности этого процесса в эксперименте, в то время как обычно для получения сведений о пространственных распреде-лениях параметров используют только численное моделирование [5,6].…”

Section: Introductionunclassified

Experimental Evaluation of the Spallation Strengh of Polymeric Targets

Demidov¹,

Казаков²,

Kurilo³

2017

PAST-TF

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Представлены результаты экспериментального определения откольной прочности полимерных материалов на примере образ-цов из оргстекла и полистирола. Исследование проводилось в диапазоне плотности энергии 35-1500 Дж/см 2 . Несмотря на близкие физико-технические параметры исследуемых полимеров (оргстекло, полистирол, эпоксидные смолы), характер их раз-рушения при импульсном объёмном энерговыделении различен [1,2]. Показано, что в полистироле трещины возникают непо-средственно из зоны энерговыделения, в оргстекле рядом с зоной энерговыделения наблюдается прозрачный неповреждённый участок, за которым образуются трещины. Определена откольная прочность полистирола, которая составила σ = 0,35 ГПа и мало отличается от откольной прочности оргстекла, что интересно, так как пространственная локализация зон разрушения об-разцов из этих двух материалов сильно различается.Ключевые слова: откольная прочность, сильноточные ускорители, электронные пучки, ударные волны, ионизирующее излу-чение. EXPERIMENTAL EVALUATION OF THE SPALLATION STRENGH OF POLYMERIC TARGETS B.A. Demidov, E.D. Kazakov, A.A. Kurilo NRC «Kurchatov Institute», Moscow, RussiaThe results of experimental evaluation of the spallation strength of polymeric materials that was identified through the examples of the samples made of Plexiglas and polystyrene are introduced in the article. The investigation was made in the rage of power density: 35-1500 J/cm 2 . The way of distraction of the investigated materials (Plexiglas and polystyrene) under pulse spatial energy release is different despite of their resembling physicotechnical characteristics [1,2]. It is described in the article that in polystyrene cracks appear directly in the area of energy release but in Plexiglas near the area of energy release you may see an undamaged transparent section and cracks appear behind it. Also spallation strength of polystyrene is defined as σ = 0.35 GPa and is practically the same as of Plexiglas that is curious because location of rupture zone of the samples of these two materials is highly different. ВВЕДЕНИЕИсследования взаимодействия ионизирующего излучения с полимерными материалами, компо-зитными и многослойными структурами на их основе являются актуальными как с точки зрения фундаментальных проблем, так и для решения прикладных задач, связанных с выбором оптимал ь-ных сочетаний материалов для защитных экранов в лабораторных и космических плазменных экс-периментах. Так, различные полимеры, многослойные структуры и композиты на их основе часто применяются в качестве защитных экранов как в лабораторных плазменных исследованиях, включая решение задач управляемого термоядерного синтеза (УТС), так и в космической технике. Ранее б ы-ло показано [2,7], что при импульсном воздействии ионизирующего излучения, характерном для аварийных режимов стационарных плазменных установок или штатных срабатываний импульс ных ускорителей и генераторов тока, включая установки для решения задач инерциального УТС, разр у-шение происходит несколько иначе, чем при непрерывном воздействии. В связи с этим ...

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“…The ε-Fe phase is nonmagnetic (the magnetic moment is equal to zero). Later, iron of this syngony was obtained by other scientists [3][4][5][6][7][8][9][10][11][12], but high pressures were used in all the methods. J.C. Jamieson suggested that, although the formation of the ε-Fe phase is most easy to carry out under nonhydrostatic conditions, but abnormal distortions under compression allow hoping for the possibility of the formation of ε-Fe under hydrostatic conditions, too.…”

Section: Overviewmentioning

confidence: 99%

Polymorphic transformations in iron and Fe-Ni alloy coatings

Жихарева¹,

Schmidt²,

Смирнова³

et al. 2016

AIP Conference Proceedings

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Iron and Fе-Ni alloy coatings containing ε-Fe produced by non-stationary deposition method AIP Conference Proceedings 1767, 020020 (2016) Abstract. For the first time, using the method of high-frequency alternating current under atmospheric pressure and a temperature of 250 °C, an iron and Fe-Ni alloy (Fe≥80 wt.%) coating was obtained from aqueous salt solutions containing an ε-Fe non-equilibrium hexagonal close-packed (HCP) phase. This phase is a result of the phase transition of the volume-centered cubic phase (bcc) α-Fe → ε-Fe. It is shown that this transition occurs according to orientational mechanism by removing the weak extreme atoms of iron in the crystal lattice of α-Fe due to the anodic constituent and the action of electromagnetic waves loosening valence bonds. It is found that the presence of the ε-Fe phase in the studied Fe and/or Fe-Ni alloy coatings provide an 6.5 times increase in corrosion-protective properties and a 2 times increase in microhardness if compared to the high-alloy steels 20Cr23Ni18 and 08Cr18Ni10.

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Shock Waves in Polycrystalline Iron

Cited by 159 publications

References 21 publications

Atomistic material behavior at extreme pressures

Atomistic material behavior at extreme pressures

Experimental Evaluation of the Spallation Strengh of Polymeric Targets

Polymorphic transformations in iron and Fe-Ni alloy coatings

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