High-intensity Pulsed Ion Beam Research Articles

Effect on microstructure of Fe80B13Si7 metallic glass irradiated by high intensity pulsed ion beam and He ions

Metallic glasses (MGs) are regarded as promising radiation-resistant materials due to their unique long-range disordered structure and abundant free volume. However, temperature sensitivity limits their application in complex irradiation environments, for example, in the fusion environment there are multiple irradiations such as He and strong thermal shock irradiation acting together on the service materials. In this work, the effects of thermal shock and He ions irradiation on the microstructure of Fe80B13Si7 MG were investigated using high intensity pulsed ion beam (HIPIB), He ions and HIPIB + He ions irradiation. It was found that Fe80B13Si7 MG remained amorphous as the main phase structure under all irradiation conditions, and no extensive surface damage occurred even at dose of up to 1.6 × 1018 He2+/cm2. Due to the strong thermal shock effect of HIPIB irradiation, the surface layer of Fe80B13Si7 MG remelted and solidified rapidly, which increased the free volume content. At the same He dose, the HIPIB induced increase in free volume content slightly promoted He bubbles growth and reduced the bubble layer depth, while it had no obvious effect on bubble layer width. As the dose increased, He bubble size and bubble layer width increased significantly. The addition of HIPIB also significantly suppressed the crystallization of Fe80B13Si7 MG induced by He ions irradiation: crystallization occurred within the He bubble layer after 4 × 1017 He2+/cm2 irradiation, while no crystallization was observed after HIPIB + 6 × 1017 He2+/cm2 irradiation. Fe80B13Si7 MG showed good resistance against HIPIB, He ions and HIPIB + He ions irradiation, and perhaps offer some unique advantages in complex irradiation environments.

Study on the damage of Zr63.5Cu23Al9Fe4.5 amorphous and crystalline alloys irradiated by high intensity pulsed ion beam

Zr63.5Cu23Al9Fe4.5 amorphous and crystalline alloys were irradiated by high intensity pulsed ion beam to investigate the effects of transient high thermal load irradiation on their microstructure, surface reflectivity and nano-hardness. When the high temperature caused by transient thermal shock did not reach the melting temperature of the alloys, there was no obvious change in the phase-structure of amorphous and crystalline alloys, and irradiation had little impact on surface reflectivity and nano-hardness. When the temperature exceeding the melting temperature, amorphous alloys still maintained amorphous strtucture, and more free volumes generated by remelting and rapid solidification process, resulting in the reduction of nano-hardness; while micrometer-sized amorphization appeared in the crystalline counterpart, which also reduced the nano-hardness. Compared with molybdenum, a candidate material of the first mirror, there was no crack on the surface and less change of surface reflectivity in amorphous and crystalline alloys.

Study on thermal shock irradiation resistance of CoCrFeMnNi high entropy alloy by high intensity pulsed ion beam

In recent years, high entropy alloys (HEAs) have attracted significant attention due to their excellent physical, chemical, mechanical properties, and good irradiation resistance, thus are considered as potential candidates for fission and fusion structural applications. CoCrFeMnNi HEA was irradiated by high intensity pulsed ion beam (HIPIB) to investigate the effects of thermal shock irradiation on its microstructure, surface morphology and mechanical properties. It was found that CoCrFeMnNi HEA maintained the face-centered cubic single-phase structure after HIPIB irradiation. The ion beam effect of irradiation produced numerous defects such as vacancies and stacking faults within the range of carbon ions. While the thermal effect reduced vacancy concentration beyond the ion range by promoting the recombination of vacancies with interstitials, and decreased the nano-hardness of CoCrFeMnNi HEA. The thermal effect and shock wave effect promoted the migration of vacancies and formed defects such as stacking faults etc. far beyond the ion range in CoCrFeMnNi HEA. Because of the very compositional complexity, the high-level chemical disorder and local lattice distortion of CoCrFeMnNi HEA, the lattice parameter was almost unchanged after HIPIB irradiation. Even if the temperature reached the melting point of CoCrFeMnNi HEA, there was no crack on the surface after surface remelting and rapid cooling. CoCrFeMnNi HEA showed good thermal stability and thermal shock irradiation resistance.

Thin film coatings material particles creation by pulsed methods in vacuum

Thin film materials particles creation pulsed methods such as magnetron sputtering HiPIMS, pulsed laser deposition PLD, vacuum arc pulsed discharge, high-intensity pulsed ion beam impact HIPIB, as well, were described. It was shown that the stream of material, created by means of an explosion action such as ablation, avalanche paired impacts and microsecond electrical disruption as well creates preconditions for nanocrystalline thin film coating manufacture.

Pulsed methods of thin film coatings deposition

The most known methods of pulsed thin film deposition such as magnetron sputtering HIPIMS, pulsed laser deposition PLD, vacuum arc pulsed deposition, high-intensity pulsed ion beams deposition HIPIB, as well, were described and analysed. It was shown that the stream of material, generated by means of a pulsed action, impacts to substrate and creates preconditions for nanocrystalline amorphous coating manufacture with superhigh hardness.

Formation, Focusing and Transport of Highintensity, Low-Energy Metal Ion Beams

High-intensity implantation of low-energy ions into various materials demonstrates the formation of long, ionalloyed layers having a thickness of tens and hundreds of micrometers. A deep incorporation of alloying elements in materials is achieved, first of all, due to a stronger radiation-induced ion diffusion at ultrahigh current densities and radiation fluence ranging from 1020 to 1022 cm2, when the diffusion coefficient exceeds its classical value derived from Arrhenius theory by several orders of magnitude. Nevertheless, the generation of low-energy ions with energies of several or a few kiloelectronvolts at high current densities of several hundreds of milliamperes per square metre and their effective transport, is a sophisticated problem. The paper studies the ballistic focusing of high-intensity pulsed ion beams at 2 kV accelerating voltage, 800 μs pulse time, 0.8 duty cycle, and their propagation through the preliminary injected low-density background plasma.

Pulse methods of strengthening nanocrystalline carbon coatings deposition

The most known methods of pulsed thin strengthening nanostructured film deposition such as magnetron sputtering HiPIMS, pulsed laser deposition PLD, vacuum arc pulsed deposition, high-intensity pulsed ion beams deposition HIPIB, as well, were described and analysed. It was shown that the stream of material, generated by means of a pulsed action, impacts to substrate and creates preconditions for nanocrystalline amorphous coating manufacture with superhigh hardness.

Modification of the WC-Co carbide surface with high-intensity pulsed ion beam

The paper presents the results of WC-Co surface modification with high-intensity pulsed ion beams at high energy density 7-8 J/cm2 per one pulse. One, five and ten pulses regimes of irradiation have been studied using scanning electron microscopy of both the surface morphology and cross-section, X-ray diffraction analysis and a nano-hardness tester. Beam irradiation with high energy density resulted in phase transformation from hexagonal α-WC to cubic ß-WC1-x. XRD analysis shows that the volume content of new formed cubic phase in the modified layer is ~ 97%.

High-intensity pulsed ion beam treatment of amorphous iron-based metal alloy

The results of intense pulsed ion beam (IPIB) treatment of the soft magnetic amorphous alloy of a FINEMET-type are presented. Foil produced from the alloy was irradiated with short (about 100 ns) pulses of carbon ions and protons with energy of up to 300 keV and an energy density of up to 7 J/cm2. X-ray diffraction, Mössbauer spectroscopy and magnetic measurements were used to investigate structural and magnetic properties of irradiated foils. It is shown that the foil remains intact after the treatment, and the crystal structure still amorphous. Spontaneous magnetization vector is found to lie almost along perpendicular to the foil plane after irradiation, whereas for the initial amorphous foil it belongs to the plane. The magnetic properties of the foil undergo changes: the coercive force decreases, the saturation induction increases slightly, and the magnetization curve has shallower slope.

Study on the damage of Fe80B13Si7 alloy with different structure by high-intensity pulsed ion beam irradiation

In this study, Fe80B13Si7 alloys with the same components but different structure, amorphous and crystal, were irradiated by high-intensity pulsed ion beams (HIPIB) with different parameters. The irradiation damage behavior of amorphous and crystal alloy by the HIPIB irradiation was studied. TEM analysis of the cross-section showed that after HIPIB irradiation, the atoms in amorphous alloy were aggregated and migrated, and the arrangement of atoms became uneven, no nanocrystal was observed. For the crystal, Fe3B, Fe3Si, Fe2B and Fe3C nanocrystals appeared besides the main structure of the α-Fe phase after HIPIB irradiation. A mass of defects appeared in the crystal. Meanwhile, XRD results showed that the lattice parameters of α-Fe phase were decreased. The effect range of the structure and defects of the crystal and the atomic arrangement of amorphous alloy by irradiation were far beyond the incident ion range. After HIPIB irradiation, the surface of amorphous alloy showed no obvious irradiation damage, and the surface of crystal showed wavy undulations. The roughness of both two alloys was increased, and the surface diffusion caused by the thermal driving and ion induction was the main mechanism of surface evolution. The decrease of the surface reflectivity of the amorphous alloy was smaller than that of the crystal.

Surface modification of ZrO2-3Y2O3 ceramics with continuous Ar+ ion beams

Microindentation and nanoindentation methods have been used to study the changes in microhardness, nanohardness and elastic modulus of partially stabilized zirconia ceramics before and after its treatment with a continuous Ar+ ion beam. The accelerating voltage was 30 kV. The experiments were performed at current densities (j) of 300 and 500 μA/cm2. The fluence was 1016–1018 cm−2. It is shown that Ar+ ion beam treatment increases the strength of the near-surface layers at a depth exceeding the penetration depth of accelerated ions by an order of magnitude or more. This indicates a long-range effect, which has been discovered earlier during ion beam treatment of metals and alloys. Treatment with ion current density of 300 μA/cm2 at a fluence of 1.1 × 1017 and 5 × 1017 cm−2 maximally increases microhardness and nanohardness (by 14%), and elastic modulus (by 20%). The phase composition of ceramics was studied using the XRD analysis. Additionally, ceramic samples were studied using the methods of Raman scattering and pulsed cathodoluminescence. The XRD analysis indicated that Ar+ ion beam treatment changes the phase composition of the near-surface layer several micrometers deep. The analysis of structural changes in the surface layers showed that continuous Ar+ ion beam treatment results in surface recrystallization, and it is not followed by negative processes, such as melting, cracking and erosion, observed during treatment by high-intensity pulsed ion beams. Shock-wave mechanisms of ceramic layer hardening and those related to accumulation of high static stresses and generation of dislocations are discussed.

Effect on mechanics properties and microstructure of molybdenum by high intensity pulsed ion beam irradiation

In this paper, high intensity pulsed ion beam (HIPIB) of 85% Cn+ + 15% H+ was used to irradiate crystalline molybdenum. Before and after irradiation, the surface structure and mechanical properties were studied with different irradiation times and energy densities. After HIPIB irradiation, stress was generated inside the molybdenum. As the energy density increases, the thermal effect which was enhanced apparently causes a preferred orientation in the molybdenum. When the energy density reaches 1.6–2.5 J/cm2 with 3 pulses, craters and cracks appear on the surface of molybdenum. Besides, the α-Mo2C phase formed in the near-surficial region of molybdenum is beneficial to the hardness increasement. After HIPIB irradiation, the ratio of average hardness (Hirr/Hunirr) and Nix-Gao model show that the macro hardness of molybdenum decreases with the increase of pulse number and energy density. Compared with the effect of ion implantation on hardness improvement, the annealing effect of HIPIB thermal irradiation plays a more important role in the reduction of molybdenum hardness. The hardness of the molybdenum decreases under the combined action.

Comprehensive material constraints incorporation in coupled thermal-mechanical responses modelling for high-intensity pulsed ion beam processing of metals

Thermodynamic numerical model is established for high-intensity pulsed ion beam (HIPIB) processing of metallic components. The HIPIB delivers a thermal energy input typically of several J/cm2 per pulse of 100 ns range. Incorporation of material constraints is emphasized in the modelling to predict residual surface stresses formation as a result of material loading, i.e. the coupled thermal-mechanical material responses of processed components. Taking tungsten as an example, five sets of material constraints were comparatively studied, including temperature-dependent thermophysical properties, Zerilli-Armstrong and Johnson-Cook constitutive equations, and simplified ones adopted in other studies by assuming constant specific heat Cp and/or thermal conductivity k, or ignoring the material yield strength, respectively. The highest surface temperature with the largest rising rate is observed at constant Cp due to the less thermal energy for the temperature increment, while the lowest surface temperature for constant k due to more thermal energy diffused. The transient temperature field evolutions induced large temperature gradients that simultaneously caused high thermal stresses. Residual surface stresses formed only if plastic strain occurred, where the model of ignoring yield strength predicted no residual stresses formation having the largest error among the five models. The models with comprehensively incorporated material constraints, particularly for incorporation of Z-A constitutive equation considering dislocation behaviors during plastic deformation, have a higher accuracy in residual surface stresses prediction. Comprehensive incorporation of material constraints in the thermodynamic model facilitates an accurate elucidation of coupled thermal-mechanical responses for resultant residual stresses under the processing load of thermal energy input.

Influence of the space charge of an ion beam on the time-of-flight diagnostics of its composition

The results of time-of-flight diagnostics of the composition of high-intensity pulsed ion beams are presented. The experiments were performed on a diode of focusing and flat geometry, in the mode of self-magnetic insulation of electrons (accelerating voltage 250–300 kV, pulse duration 120 ns, ion current density 20–300 A/cm2), and a focusing diode in an external magnetic insulation mode (300 kV, 80 ns, 100–200 A/cm2). A delay in the registration of protons by 40–50 ns (on the drift path 14–16 cm) was found in the absence of a delay in the registration of heavy ions. It has been shown that this delay can be related to the deceleration of light ions during the transport from the diode to a collimated Faraday cup. This effect of spatial compression of the ion beam in the direction of the drift increases its pulse power but complicates the time-of-flight diagnostics of its composition.

Tribological behaviors in air and seawater of CrN/TiN superlattice coatings irradiated by high-intensity pulsed ion beam

Surface integrity and interface structure of coating materials play a key role in tribological and corrosion behaviors in harsh working environments in nuclear power plants. In this work, we focus on the investigations of tribological behaviors in air and seawater of CrN/TiN superlattice coatings deposited by the combined deep oscillation magnetron sputtering with pulsed dc magnetron sputtering, which were irradiated by high-intensity pulsed ion beam (HIPIB) with ion energy density of 1–3 J/cm2 and shot number of 1–5. At 1 J/cm2, the increased shot number leads to a broaden (111) peak of face-centered cubic crystal structure, indicating grain size refinement. At 3 J/cm2, the increased shot number results in the coarsening grain, and superlattice structure gradually disappeared at 2 shots, finally the coatings fell off from substrate at 5 shots. The highest hardness (H), H/E* (E*, effective Young’s modulus) and H3/E*2 of the coatings irradiated at 1 J/cm2 and 5 shots are achieved at 38.7 GPa, 0.1 and 0.387, respectively. The increased ion energy density and shot number result in the decrease in Rockwell C HF adhesion level from HF1 to HF6. At 1 Jcm−2 and 1 shot, tribological behavior of irradiated coatings in air was dominated by oxidative wear with coefficient of friction (COF) of 0.51 and specific wear rate of 4.2 × 10−7mm3N−1m−1. The irradiated coatings show excellent tribocorrosion properties in seawater with high open circuit potential of 0.32 V, low COF of 0.14 and specific tribocorrosion rate of 6.1 × 10−8mm3N−1m−1 without pitting corrosion under moderate HIPIB irradiation due to high surface integrity and stability of well-defined interfaces and dense microstructure. With an increase of energy density and shot number, wear mechanism in air changes to severe adhesive and oxidative wear, while tribocorrosion mechanism is gradually dominated by plough wear coupled with pitting corrosion.

Extending the range of measurement of thermal imaging diagnostics of a high-intensity pulsed ion beam

AbstractThermal imaging diagnostics was used as a surface temperature mapping tool to characterize the energy density distribution of a high-intensity pulsed ion beam. This approach was tested on the TEMP-6 accelerator (200–250 kV, 150 ns). The beam composition included carbon ions (85%) and protons, and the energy density in the focus was 5–12 J/cm2. Targets of stainless steel, titanium, brass, copper, and tungsten were examined. Our observations show that the maximum energy density measured with the thermal imaging diagnostics considerably exceeds the ablation threshold of the targets. An analysis of the overheating mechanisms of each target was carried out, including metastable overheating of the target to above its boiling temperature during rapid heating; formation, migration, and the subsequent annealing of fast radiation-induced defects in the target under ion beam irradiation. This expands the range of energy density measurement for this thermal imaging diagnostics from 2–3 J/cm2 up to 10–12 J/cm2 but introduces error into the results of measurement. For a stainless steel target, this error exceeds 15% at an energy density of more than 4 J/cm2. A method of correcting the results of the thermal imaging diagnostics is developed for a pulsed ion beam under conditions of intense ablation of the target material.

Influence of irradiation intensity on corrosion properties of microarc oxidation film on AZ31 magnesium alloy with HIPIB

Purpose The purpose of this paper is to investigate the effect of high-intensity pulsed ion beam (HIPIB) intensity on the structure and corrosive properties of microarc oxidation (MAO) films on AZ31 magnesium alloy and explore the mechanism for modified anti-corrosion properties of irradiated films. Design/methodology/approach The energy deposited on the coating surface influences the remelting process of the MAO coatings significantly, which was closely related to the intensity of HIPIB; therefore, HIPIB with various intensities of 100-350 A/cm2, was selected to modify the MAO films on AZ31 magnesium alloy. The changes in film structure and phase structure of modified films were characterized by scanning electron microscopy and X-ray diffractometry (XRD) with CuKα, respectively. The corrosive behavior of the MAO films was featured with polarization curves and electrochemical impedance spectrum in 3.5 per cent NaCl solution on a PAR 2273 electrochemical workstation. Findings The results clearly show that a dense, continual and remelted layer with a few micrometers in thickness was obtained on the irradiated surface at 200 A/cm2, which are mainly responsible for the modified and optimal anti-corrosion property of MAO films by suppressing/retarding the process of the corrosive electrolyte infiltration into magnesium substrate surface. Originality/value The paper reveals that HIPIB irradiation could modify the corrosion resistance by producing a remelted compact layer on the MAO film surface at a suitable irradiation parameter and explored the modified mechanism of MAO films.

High-intensity pulsed ion beam focusing by its own space charge

AbstractThe paper presents the results of a study on propagation and focusing of high-intensity pulsed ion beams, produced by a self-magnetically insulated diode of semi-cylindrical geometry at the TEMP-6 accelerator (120 ns, 200–250 kV). We examined the space-charge neutralization of the beam, the energy density in the focus, the divergence of the beam, and its shot-to-shot displacement in the focal plane. It is found that the concentration of low-energy electrons in the beam is 1.3–1.5 times higher than the concentration of ions. We observed additional ion focusing by its own space charge. With an increase in the density of the net negative (electrons and ions) charge of the beam from 3.6 to 9 µC/cm2, the total divergence (the sum of the beam divergence in the vertical and horizontal planes) decreases from 11.4 to 4.5°. It leads to an increase in the energy density in the focus from 4 up to 10–12 J/cm2. To increase the electrons concentration in the beam, a metal grid installed in the ion beam transport region was used.

Structural Modification of Graphene on Copper Substrates Irradiated by Nanosecond High-Intensity Ion Beams

Interaction of a nanosecond high-intensity pulsed ion beam with thin graphene films on copper substrates is analyzed. Methods of Raman spectroscopy are used to investigate the degree of graphene degradation depending on the integral implanted dose. The role of the substrate in the structural degradation of graphene irradiated by charged particle beams is demonstrated using the software package SRIM, intended for modeling radiative defect cascades under irradiation by charged particle beams, and the data on radiation resistance of graphene available in the literature.

Effects of high-intensity pulsed ion beam irradiation on the structural thermal stability of Fe80Si7.43B12.57 metallic glass

A high-intensity pulsed ion beam was used to irradiate Fe80Si7.43B12.57 metallic glass at different energy densities and numbers of pulses to study its structural thermal stability. A large number of round holes and a few bumps appeared on the surface of the glass after 300 pulses. No obvious damage was observed on the surface after irradiation at different energy densities. High-resolution transmission electron microscopy showed that this irradiation had a strong influence on the near-surface atomic arrangement of the glass. Irradiation induced strong migration and aggregation of atoms within the glass, causing an uneven atomic arrangement. Although there was an ordered arrangement of atoms, the metallic glass remained amorphous. The surface reflectivity of the metallic glass decreased slightly after irradiation. The number of irradiation pulses had greater impact on this Fe-based metallic glass than their energy density.