High-intensity Pulsed Ion Beam Irradiation 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 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.

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.

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.

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.

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.

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.

High-Intensity Pulsed Ion Beam Irradiation for Structural Stability of Metallic Glass Ni62Ta38

Metallic glass Ni 62 Ta 38 was irradiated with the high-intensity pulsed ion beams (HIPIB) at an energy density of 0.32 J/cm 2 and different impulse times to study the structural thermal stability. Metallic glass Ni 62 Ta 38 remained an amorphous structure after HIPIB irradiation at different impulse times. However, the arrangement of atomic structure in the depth of about 700 nm from the surface of metallic glass became more disordered after irradiation. When the number of pulses increased to 300, a small amount of “bumps” appeared on the surface of the metallic glass, and no radiation damage such as cracks occurred. It shows that the metallic glass Ni 62 Ta 38 has good resistance to thermal damage from HIPIB irradiation and good structural stability.

Significance of surface integrity on high-performance manufacturing by surface modification

It has been proved that surface integrity involving numerous surface integrity parameters has a profound influence on component performance. However, it is still difficult to achieve a high performance of combined functional properties since the surface integrity of the high-performance component is frequently limited by merely using material removal manufacturing. In this work, surface modification is alternatively employed to explore influence of various surface integrity parameters in a controllable way on achieving the high-performance manufacturing of components with combined properties including anti-fatigue performance and corrosion resistance, thermal insulating and oxidation resistance, temperature sensing and wear resistance, otherwise unattainable in conventional material removal manufacturing. Three typical surface modification techniques principally based on a series of processing loads, such as thermochemical load from plasma-based low-energy ion implantation, thermomechanical load from ion beam shock processing by high-intensity pulsed ion beam irradiation, and chemical load from non-aqueous sol-gel thin film deposition respectively, were selected for generating a new surface layer on base materials of components toward an improved surface integrity with desired multiple surface integrity parameters. In all cases, two categories of surface integrity parameters are identified in relation to the functional properties of components, i.e., surface features and surface characteristics, where the former include the features of topography and chemical composition, grain morphology, and phase structure, etc. on surface and subsurface directly created by the surface modification, and the latter include all the physical and chemical properties associated with the new surface layer, such as microhardness, residual stress, electrical potential, optical properties, etc. The surface features and surface characteristics in surface integrity present a synergetic effect on the high performance with combined properties as a result of coupled interactions between the surface integrity parameters. Therefore, the multiple surface integrity parameters controllable with active interactions achieved by surface modification processes effectively improve the surface integrity according to the desired high-performance component of combined properties, enabling a high-performance manufacturing.

Influence of high-intensity pulsed ion beam irradiation energy on magnesium alloy surface modification

Magnesium alloys surface modified by high-intensity pulsed ion beam irradiation are studied by MD simulation. The specimens containing defects were modeled to investigate the effect of high-intensity pulsed ion beam irradiation on surface area and defect size. It was found that the surface area mainly depend on the value of irradiation energy. The kinds of defects in the sub-surface have little influence on the surface area. The inner surface of the defect decreases with the increasing irradiation energy. There was a nonlinear relationship between the irradiation energy and the defect size.

Tribological behavior of WC–Ni cemented carbide irradiated by high-intensity pulsed ion beam

The tribological behavior of WC–Ni cemented carbide irradiated by high-intensity pulsed ion beam (HIPIB) at ion current densities of 100, 200 and 300A/cm2 with 10 shots was studied under dry sliding tests against GCr15 bearing steel on a block-on-ring tribometer with 98N and 0.47m/s in order to explore the effect of HIPIB irradiation on the tribological property of WC–Ni cemented carbide. The cross-sectional microstructure, phase composition and microhardness of the irradiated WC–Ni samples were investigated by using scanning electron microscope (SEM), X-ray diffractometer (XRD) and Vickers testers. It was found that HIPIB irradiation led to significant surface hardening down to a hundred micrometers on the WC–Ni samples, and the reduction in specific wear rate and friction coefficient. The specific wear rate of irradiated samples decreased with increasing ion current densities. The original WC–Ni samples predominantly underwent an abrasive wear process accompanied with notable fragmentation and pullout of WC grains. The wear process of irradiated samples involved micro-abrasion and local adhesion in the initial stage, followed by a steady and mild abrasive wear. The preferential removal of Ni binder and pullout of WC grains is greatly suppressed for the irradiated samples due to combined enhancements in the carbide-binder bonding and binder phase strengthening by the HIPIB irradiation.

Surface morphology, microstructure and properties of as-cast AZ31 magnesium alloy irradiated by high intensity pulsed ion beams

Abstract High intensity pulsed ion beam (HIPIB) irradiation was performed as surface modification to improve the properties of as-cast AZ31 magnesium (Mg) alloys. The surface morphology and microstructure of the irradiated Mg alloys were characterized and their microhardness, wear resistance and corrosion resistance before and after HIPIB irradiation were measured. The results show that the formation of crater on the surface was attributed to the particles impacted from the irradiated cathode material. HIPIB irradiation resulted in more vacancy defects on the surface of the material. Moreover, new dislocations were generated by the reaction between vacancies, and the dislocation configuration was also changed. These variations caused by the HIPIB are beneficial for improving the material properties. After 10 shots of irradiation, the average microhardness increased by 27.1% but the wear rate decreased by 38.5%. The corrosion rate was reduced by 24.8% according to the salt spray corrosion experiment.

Microstructural evolution and its correlation with hardening of WC-Ni cemented carbides irradiated by high-intensity pulsed ion beam

Modification of WC-Ni cemented carbides was studied by using high-intensity pulsed ion beam (HIPIB) irradiation. Surface hardening can be achieved for all the HIPIB-irradiated surfaces but of different degree at ion current density of 50–300A/cm2 up to 10 shots. Thermal and dynamic process of remelting and ablation under HIPIB irradiation led to significant changes in surface morphology, phase structures and composition of the irradiated surfaces. Gradual transitions to remelting densification, selective ablation of Ni binder and phase transformation from hexagonal α-WC to cubic non-stoichiometric β-WC1−x were found by adjusting the irradiation intensity and shot number, explaining the hardness enhancement of cemented carbides. It is revealed that the densification with defects healing and the lower binder content can significantly enhance the hardness whereas occurrence of the metastable non-stoichiometric phase and limited surface cracking may slightly lower the hardness. The parameter-dependent variation of surface hardening degree is thus attributed to single or multiple contributions from remelting densification, binder removal and phase transformation. It is demonstrated by the HIPIB processing that mechanical properties of WC based cemented carbides may be effectively improved by decreasing the binder phase content and enhancing the bonding strength between carbide grain and binder with less defect density.

Phase transformation under beam-target interactions during high-intensity pulsed ion beam irradiation at low pressure

AbstractNitrides and/or carbonitrides formation of high efficiency was found on titanium target under irradiation of high-intensity pulsed ion beam (HIPIB) with a few shots at a low pressure of 10−2 Pa order, which is extraordinary in comparison with conventional thermo-chemical diffusion process such as gas nitriding and/or carbonitriding of metals necessarily heated at high temperatures during a processing time of hours. The underlying mechanism of the nitrides and carbonitrides formation on titanium targets was explored by a comparative study on three typical HIPIB sources, i.e., TEMP-6, TEMP-4M, and ETIGO-II, varying the irradiation intensity within several J/cm2 per shot of a 60–70 ns pulse duration and the shot number of similar ion species. It is revealed that ambient gases and ion source material are the main sources providing the nitrogen and carbon species for the phase transformation on titanium target at the low pressures, whereas the ion species of HIPIB composition is negligible at a low implantation dose of 1013–1014 ions/cm2. The adsorbed gaseous species, the deposited layer of the ion source material, and in-situ formed compound top layer from reactions between ablation plasma and the ambient species during HIPIB irradiation, can be effectively incorporated into the irradiated target surfaces under a controlled HIPIB-target interaction.

Surface composition, microstructure and corrosion resistance of AZ31 magnesium alloy irradiated by high-intensity pulsed ion beam

Abstract High-intensity pulsed ion beam (HIPIB) irradiation of AZ31 magnesium alloy is performed and electrochemical corrosion experiment of irradiated samples is carried out by using potentiodynamic polarization technology in order to explore the effect of HIPIB irradiation on corrosion resistance of magnesium alloy. The surface composition, cross-sectional morphology and microstructure are characterized by using electron probe microanalyzer, optical microscope and transmission electron microscope, respectively. The results indicated that HIPIB irradiation leads to a significant improvement in corrosion resistance of magnesium alloy, in terms of the considerable increase in both corrosion potential and pitting breakdown potential. The microstructural refinement and surface purification induced by HIPIB irradiation are responsible for the improved corrosion resistance.

Dynamic response of metals under high-intensity pulsed ion beam irradiation for surface modification

A piezoelectric transducer based on lead–zirconte–titanate (PZT) piezoelectric ceramic thin plate was applied to characterize the stress waves in titanium targets under high-intensity pulsed ion beam (HIPIB) irradiation at a peak accelerating voltage of 350 kV and an ion current density up to 400 A/cm 2 with pulse duration of about 150 ns. The magnitude of recorded stress wave signals was increased along with the irradiation intensity, presenting a slow growth with a value below 100 V in the range of 200–300 A/cm 2, and then a rapid increase of about four times up to 400 A/cm 2. The measured stress waves were explained by space–time diagram analysis. The generation and propagation of the stress wave can be attributed to the coupled thermal–dynamic effects during HIPIB irradiation onto metallic targets, where the thermal shock due to ultra-fast heating/cooling process and the recoil impulse due to ablation process have a combined contribution to the induced stress waves, dependent on the irradiation intensity. It is indicated that a fast attenuation of stress wave proceeded during its propagation from the irradiated surface to the target/PZT interface. The large amount of energy delivered by the stress wave effectively converted and dissipated into plastic deformation and/or defects formation in target materials. The dynamic response of metallic materials under HIPIB irradiation accounts for the effective surface modification of metals and alloys into a depth well beyond the ion range.

Effect of High-Intensity Pulsed Ion Beam Irradiation on the Electrochemical Corrosion Behavior of AZ31 Magnesium Alloy

HIPIB irradiation experiment is carried out at a specific ion current density of 1.1 J/cm2 with shot number from one to ten in order to explore the effect of shot number on electrochemical corrosion behavior of magnesium alloy. Surface morphologies, microstructure and corrosion resistance of the irradiated samples are examined by scanning electron microscopy (SEM), transmission electron microscope (TEM) and potentiodynamic polarization technique, respectively. It is found that HIPIB irradiation leads to the increase in open circuit potential, corrosion potential and breakdown potential, and the decrease in the corrosion current density and the corrosion rate as compared to the original sample. The improved corrosion resistance is mainly attributed to the grain refinement and surface purification induced by HIPIB irradiation.

Dry sliding tribological behavior of AZ31 magnesium alloy irradiated by high-intensity pulsed ion beam

The dry sliding tribological behavior of AZ31 magnesium alloy irradiated by high-intensity pulsed ion beam (HIPIB) at energy density of 3.4 J/cm 2 with 10 shots is investigated by dry sliding wear tests in order to explore the effect of HIPIB irradiation on tribological property of magnesium alloy. Surface morphologies, composition and structure of the irradiated AZ31 magnesium alloys are examined by electron probe microanalysis (EPMA) and X-ray diffraction (XRD). The results indicated that HIPIB irradiation led to the increase in surface microhardness and the reduction in friction coefficient and wear rate. Wear rate for both the original and the irradiated samples increased with increasing sliding load from 0.1 to 0.5 N. The transition from severe metallic wear to mild oxidative wear induced by HIPIB irradiation was observed by a combined analysis in surface morphology and chemical composition of wear tracks, mechanically mixed materials and wear debris, which is mainly attributed to the significant increase in microhardness resulting from grain refinement on the irradiated surface. In addition, defects induced by HIPIB irradiation promoted the diffusion of oxygen during sliding wear and therefore led to the formation of compact mixed materials and protective films on the wear tracks surface, which also contributes to the transition in wear mechanism of AZ31 magnesium alloy induced by HIPIB irradiation.

M-1 A Multi Rig Screening Test for Thin Ceramic Coatings in Bio-Tribological Applications

Based on the surface microstructure of EB-PVD ZrO2 coatings, the ablation effects of a novel method for ceramic modification technique by high-intensity pulsed ion beam irradiation have been studied numerically. Taking the nonlinear depositing energy of ions in the coatings calculated by Monte Carlo methods as the thermal source term in heat transfer equations, the surface melting process and the evolution of temperature of ZrO2 specimens induced by HIPIB irradiation were obtained. About 1 μm in thickness of ZrO2 ceramic was re-solidified after melting, a dense modification coat layer formed, and near the top surface an even denser layer formed. During the calculation the latent heat of ZrO2 is introduced to consider the additional heat due to the phase change between solid–liquid and liquid–gas states. The numerical result about the ablation melted thickness of surface layer is in reasonable agreement with those measured by HIPIB irradiation experiments.

Wear mechanism of AZ31 magnesium alloy irradiated by high-intensity pulsed ion beam

The wear resistance and wear mechanism of AZ31 magnesium alloy irradiated by high-intensity pulsed ion beam (HIPIB) at an ion current density of 100 A/cm 2 with shot number from one to ten are investigated by dry sliding wear tests. The cross-sectional microstructure and surface microhardness of the irradiated AZ31 magnesium alloys are examined by optical microscopy (OM) and Vickers tester, respectively. It is found that surface hardness increased with increasing shot number, from an original value of 570 MPa to a maximal value of 820 MPa with ten shots, and the wear rate of the samples irradiated with five and ten shots was about one order of magnitude less than that of the original sample. The transition from severe metallic wear to mild oxidative wear induced by HIPIB irradiation was identified through a combined analysis in surface morphology and chemical composition of wear tracks, mechanically mixed materials, wear debris and wear scars of counterface steel ball by using scanning electron microscopy (SEM) and electron probe microanalysis (EPMA), which is mainly attributed to the significant increase in microhardness resulting from grain refinement on the irradiated surface.