How do energetic ions damage metallic surfaces?

Osetsky, Yu.N.; Calder, A.F.; Stoller, R.E.

doi:10.1016/j.cossms.2014.12.001

Cited by 32 publications

(15 citation statements)

References 25 publications

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“…12 Likewise, the interactions of these shockwaves with a free surface can lead to the surface roughening and creation of huge vacancy dislocation loops. 15,16 In the 0.25-ps snapshot, one can see that the sonic wave propagates without creating low-density regions. For this reason, the supersonic regime is often considered destructive, whereas the sonic regime is considered non-destructive.…”

Section: Resultsmentioning

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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Section: Resultsmentioning

confidence: 99%

Atomistic material behavior at extreme pressures

2016

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“…Experiments on Xe + ion irradiation of In, Ag, Pb, Au showed that the number of craters per ion increases with an increase in the material density [1]. Dislocation loops in the irradiated metals are observed in experiments [2][3][4] and computer simulations [5,6]. For example, a greater number of loops was indicated in the thick iron sample, as compared to the bulk material, irradiated with Fe+ ions of energy 500 keV [2].…”

Section: Introductionmentioning

confidence: 86%

“…The free surfaces influence not only the number and position of survived point defects, but also the type of the formed damage near the surface. In particular, the formation of craters and dislocation loops in the surface region after the ion irradiation was found in the experimental [1][2][3][4] and theoretical studies [5,6]. Experiments on Xe + ion irradiation of In, Ag, Pb, Au showed that the number of craters per ion increases with an increase in the material density [1].…”

Section: Introductionmentioning

confidence: 90%

“…It was shown that the free surfaces have a significant impact on the evolution of atomic displacement cascades. In particular, the number of survived point defects in crystallites with the irradiated surface may be two orders of magnitude greater than the corresponding number in bulk samples [5,6]. If a cascade is generated in the volume of the material the fraction of self-interstitial atoms (SIAs) in the formed clusters is higher than the fraction of vacancies.…”

Section: Introductionmentioning

confidence: 99%

“…It is known that collision of ion with lattice atoms leads to generation of atomic displacement cascades near the surface of the material. The peculiarities of generation and evolution of atomic displacement cascades in the surface region during ion bombardment are actively investigated [1][2][3][4][5][6]. It was shown that the free surfaces have a significant impact on the evolution of atomic displacement cascades.…”

Section: Introductionmentioning

confidence: 99%

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Atomistic simulation of structural damage during ion irradiation of iron single crystals

Korchuganov

Zolnikov

Крыжевич

2017

J. Phys.: Conf. Ser.

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Abstract. The evolution of atomic displacement cascades initiated near free surfaces with different crystallographic orientations in bcc iron specimens was studied on the base of the molecular dynamics approach. The craters surrounded by adatom mounds were formed in the case of the (111) surface irradiation. The dislocation loops consisted of vacancies were generated after the (110) surface irradiation. The dislocation Burgers vector was a/2 <111> or a <100>. It was shown that the type of structural damage is determined by the anisotropy of propagation of shock waves generated by atomic displacement cascades. For energies of the atomic displacement cascade lower than 20 keV the number of adatoms and survived point defects was higher for specimen with the (110) free surface due to the different character of surface damage. The increase in the cascade energy up to 20 keV results in formation of almost the equal number of survived point defects for the (110) and (111) free surfaces as displacement cascades were developed on larger distance from the irradiated surfaces.

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