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20 pages, 7633 KB

Open AccessArticle

Corrosion Performance of Chemically Passivated and Ion Beam-Treated Austenitic–Martensitic Steel in the Marine Environment

by Viktor Semin, Alexander Cherkasov, Konstantin Savkin, Maxim Shandrikov and Evgeniya Khabibova

J. Manuf. Mater. Process. 2025, 9(5), 167; https://doi.org/10.3390/jmmp9050167 - 20 May 2025

Viewed by 847

Abstract

In the present work, chemical and ion beam surface treatments were performed in order to modify the electrochemical behavior of industrial austenitic–martensitic steel VNS-5 in 3.5 wt. % NaCl. Immersion for 140 h in a solution containing 0.05 M potassium dichromate and 10% [...] Read more.

In the present work, chemical and ion beam surface treatments were performed in order to modify the electrochemical behavior of industrial austenitic–martensitic steel VNS-5 in 3.5 wt. % NaCl. Immersion for 140 h in a solution containing 0.05 M potassium dichromate and 10% phosphoric acid promotes formation of chromium hydroxides in the outer surface layer. By means of a new type of ion source, based on a high-current pulsed magnetron discharge with injection of electrons from vacuum arc plasma, ion implantation with Ar⁺ and Cr⁺ ions of the VNS-5 steel was performed. It has been found that the ion implantation leads to formation of an Fe- and Cr-bearing oxide layer with advanced passivation ability. Moreover, the ion beam-treated steel exhibits a lower corrosion rate (by ~7.8 times) and higher charge transfer resistance in comparison with an initial (mechanically polished) substrate. Comprehensive electrochemical and XPS analysis has shown that a Cr₂O₃-rich oxide film is able to provide an improved corrosion performance of the steel, while the chromium hydroxides may increase the specific conductivity of the surface layer. A scheme of a charge transfer between the microgalvanic elements was proposed. Full article

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15 pages, 6405 KB

Open AccessArticle

The Effect of Pulse Frequency on the Microstructure and Corrosion Resistance of an AZ31B Magnesium Alloy Composite Coating with Electron-Beam Remelting and Micro-Arc Oxidation

by Yinghe Ma, Zhen Yu, Jinpeng Zhang, Yonghui Hu, Mengliang Zhou, Jinhui Mei, Zhihui Cai, Wenjian Zheng and Jianguo Yang

Materials 2025, 18(9), 1962; https://doi.org/10.3390/ma18091962 - 25 Apr 2025

Viewed by 491

Abstract

This study presents a systematic investigation into the influence of pulse frequency on the micro-arc oxidation (MAO) coating of AZ31B magnesium alloy following electron-beam remelting (EBR). The morphology, thickness, and corrosion resistance of the EBR-MAO composite coating were meticulously analyzed across various pulse [...] Read more.

This study presents a systematic investigation into the influence of pulse frequency on the micro-arc oxidation (MAO) coating of AZ31B magnesium alloy following electron-beam remelting (EBR). The morphology, thickness, and corrosion resistance of the EBR-MAO composite coating were meticulously analyzed across various pulse frequencies (100 Hz, 200 Hz, 300 Hz, 400 Hz) employing scanning electron microscopy (SEM), X-ray diffraction (XRD), and electrochemical measurement techniques. The results show that as the pulse frequency escalates from 100 Hz to 400 Hz, the average thickness of the EBR-MAO composite coating diminishes from 41.1 μm to 38.5 μm, reduced by 6.7% compared to 10.4% in the MAO coating. Concurrently, the porosity exhibits a reduction from 1.93% to 1.35%, accompanied by a densification of the coating’s structure. High pulse frequencies yield coatings with enhanced smoothness and fewer defects. Notably, the corrosion resistance of the coatings demonstrates significant improvement at higher frequencies (400 Hz) compared to their lower-frequency (100 Hz) counterparts, as evidenced by a tenfold increase in corrosion current density. This research underscores the pivotal role of pulse frequency in optimizing the protective qualities of MAO coatings on magnesium alloys. Full article

(This article belongs to the Special Issue Latest Research in Joining and Welding Processes)

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13 pages, 18986 KB

Open AccessArticle

Thermal Modelling of Metals and Alloys Irradiated by Pulsed Electron Beam: Focus on Rough, Heterogeneous and Multilayered Materials

by Andrea Lucchini Huspek, Valentina Mataloni, Ali Mohtashamifar, Luca Paterlini and Massimiliano Bestetti

J. Manuf. Mater. Process. 2025, 9(4), 130; https://doi.org/10.3390/jmmp9040130 - 15 Apr 2025

Viewed by 733

Abstract

Low-Energy High-Current Electron Beam (LEHCEB) is an innovative vacuum technology employed for the surface modification of conductive materials. Surface treatments by means of LEHCEB allow the melting and rapid solidification of a thin layer (up to ~10 μm) of material. The short duration [...] Read more.

Low-Energy High-Current Electron Beam (LEHCEB) is an innovative vacuum technology employed for the surface modification of conductive materials. Surface treatments by means of LEHCEB allow the melting and rapid solidification of a thin layer (up to ~10 μm) of material. The short duration of each pulse (2.5 μs) allows for the generation of high thermal rates, up to 10⁹ K/s. Due to the peculiar features of LEHCEB source, in situ temperature monitoring inside the vacuum chamber is unfeasible, even with the most rapid IR pyrometers available on the market. Therefore, multiphysics simulations serve as a tool for predicting and assessing the thermal effects induced by electron beam irradiation. COMSOL Multiphysics was employed to study the thermal behaviour of metals and alloys at the sub-microsecond time scale by implementing both experimental power time profiles and semi-empirical electron penetration functions. Three case studies were considered: (a) 17-4 PH steel produced by Binder Jetting, (b) biphasic Al-Si13 alloy, and (c) Magnetron Sputtering Nb films on Ti substrate. The influence on the thermal effects of electron accelerating voltage and number of pulses was investigated, as well as the role of the physicochemical properties of the materials. Full article

(This article belongs to the Special Issue New Trends in Precision Machining Processes)

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19 pages, 33574 KB

Open AccessArticle

Mechanical and Thermal Contributions to the Damage Suffered by an Aeronautical Structure Subjected to an Intense and Sudden Electrical Discharge

by Bryan Better, Aboulghit El Malki Alaoui, Christine Espinosa, Michel Arrigoni, Nathan Menetrier, Chabouh Yazidjian, Serge Guetta, Frédéric Lachaud, Christian Jochum, Michel Boustie and Didier Zagouri

Aerospace 2025, 12(3), 235; https://doi.org/10.3390/aerospace12030235 - 14 Mar 2025

Cited by 1 | Viewed by 647

Abstract

Lightweight aeronautical structures and power generation structures such as wind turbines are fitted with protected external layers designed and certified to withstand severe climatic events such as lightning strikes. During these events, high currents flow through the structural protection but are likely to [...] Read more.

Lightweight aeronautical structures and power generation structures such as wind turbines are fitted with protected external layers designed and certified to withstand severe climatic events such as lightning strikes. During these events, high currents flow through the structural protection but are likely to induce effects deeper in the supporting composite material and could even reach or perforate pressurized tanks. In situ measurements are hard to achieve during current delivery due to the severe electromagnetic conditions, and the lightning strike phenomenon on these structures is not yet fully investigated. To gain a better understanding of the physics involved, similarities in direct damage between lightning-struck samples and those subjected to pulsed lasers and an electron gun are analyzed. These analyses show the inability of a pure mechanical contribution to fully reproduce the shape of the delamination distribution of lightning strikes. Conversely, the similarities in effect and damage with the thermomechanical contribution of electron beam deposition are highlighted, particularly the increase in core delamination due to the paint and the apparent similarities in delamination distribution. Full article

(This article belongs to the Special Issue 14th EASN International Conference on Innovation in Aviation & Space towards Sustainability Today & Tomorrow)

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16 pages, 76542 KB

Open AccessArticle

Low-Energy High-Current Pulsed Electron Beam Surface Treatment on the Tribological Behavior of 17-4PH Steel Produced via Binder Jetting

by Lorenza Fabiocchi, Marco Mariani, Andrea Lucchini Huspek, Matteo Pozzi, Massimiliano Bestetti and Nora Lecis

Lubricants 2025, 13(2), 42; https://doi.org/10.3390/lubricants13020042 - 21 Jan 2025

Cited by 1 | Viewed by 1267

Abstract

Stainless steel 17-4PH is valued for its high strength and corrosion resistance but poses machining challenges due to rapid tool wear. This research investigates the use of pulsed electron beam surface treatment to enhance the surface properties of components fabricated by binder jetting [...] Read more.

Stainless steel 17-4PH is valued for its high strength and corrosion resistance but poses machining challenges due to rapid tool wear. This research investigates the use of pulsed electron beam surface treatment to enhance the surface properties of components fabricated by binder jetting additive manufacturing. The aim is to improve the tribological performance compared to the as-sintered condition and the H900 aging process, which optimizes hardness and wear resistance. Printed samples were sintered in a reducing atmosphere and superficially treated with an electron beam by varying the voltage and the pulse count. Results showed that the voltage affects the roughness and thickness of the treated layer, while the number of pulses influences the hardening of the microstructure and, consequently, the wear resistance. A reciprocating linear pin-on-disk wear test was conducted at 2 N and 10 Hz. Surface-treated samples exhibited lower coefficients of friction, though the values approached those of aged samples after the abrasion of the melted layer, indicating a deeper heat-affected zone formation. Still, the friction remained lower than that of as-printed specimens. This study demonstrates that optimizing electron beam parameters is vital for achieving surface performance comparable to bulk aging treatments, with significant implications for long-term wear resistance. Full article

(This article belongs to the Special Issue Surface Engineering via Advanced Manufacturing for Tribological Performance)

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12 pages, 25572 KB

Open AccessCommunication

Improving Corrosion Resistance of Zircaloy-4 via High-Current Pulsed Electron Beam Surface Irradiation

by Shen Yang, Heran Yao, Zhiyong Hu and Tao Chen

Materials 2025, 18(1), 76; https://doi.org/10.3390/ma18010076 - 27 Dec 2024

Viewed by 660

Abstract

Zircaloy-4 is extensively used in nuclear reactors as fuel element cladding and core structural material. However, the safety concerns post-Fukushima underscore the need for further enhancing its high-temperature and high-pressure water-side corrosion resistance. Therefore, this study aimed to investigate the effects of high-current [...] Read more.

Zircaloy-4 is extensively used in nuclear reactors as fuel element cladding and core structural material. However, the safety concerns post-Fukushima underscore the need for further enhancing its high-temperature and high-pressure water-side corrosion resistance. Therefore, this study aimed to investigate the effects of high-current pulsed electron beam (HCPEB) irradiation on the microstructures and corrosion resistance of Zircaloy-4, with the goal of improving its performance in nuclear applications. Results showed that after irradiation, the cross-section of the sample could be divided into three distinct layers: the outermost melted layer (approximately 4.80 μm), the intermediate heat-affected zone, and the bottom normal matrix. Large numbers of twin martensites were induced within the melted layer, which became finer with increasing irradiation times. Additionally, plenty of ultrafine/nanoscale grains were observed on the surface of the sample pulsed 25 times. Zr(Fe, Cr)₂ second-phase particles (SPPs) were dissolved throughout the modified layer and Fe and Cr elements were uniformly distributed under the action of HCPEB. As a result, the corrosion resistance of the sample pulsed 25 times was significantly improved compared to the initial one. Research results confirmed that HCPEB irradiation is an effective method in improving the service life of Zircaloy-4 under extreme environmental conditions. Full article

(This article belongs to the Special Issue Microstructures and Properties of Corrosion-Resistant Alloys)

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13 pages, 7047 KB

Open AccessArticle

Effect of High-Current Pulsed Electron Beam on Microstructure and Surface Properties of Ag-10La_0.7Sr_0.3CoO₃ Composites

by Huanfeng Zhang, Bo Gao, Lei Wang, Wenhuan Shen, Pengshan Lin, Xin Lan and He Liu

Surfaces 2024, 7(3), 739-751; https://doi.org/10.3390/surfaces7030048 - 12 Sep 2024

Viewed by 1130

Abstract

This paper investigates the enhancement of the microstructure and properties of Ag-10La_0.7Sr_0.3CoO₃ composites, prepared by powder metallurgy, through the application of high-current pulsed electron beam (HCPEB) irradiation. The X-ray diffraction results showed that the irradiated samples exhibited selective [...] Read more.

This paper investigates the enhancement of the microstructure and properties of Ag-10La_0.7Sr_0.3CoO₃ composites, prepared by powder metallurgy, through the application of high-current pulsed electron beam (HCPEB) irradiation. The X-ray diffraction results showed that the irradiated samples exhibited selective orientations on the surface of their (200) and (311) crystal planes. Microstructural observations revealed a dense remelted layer on the samples’ surface after HCPEB irradiation. The surface hardness of the samples increased after 15 treatments, showing an improvement of 36.76%. This is primarily attributed to fine-grain strengthening, surface remelting, and recrystallization. Further, the electrical conductivity of the samples treated 15 times increased by 74.8% compared to that of the original samples. Electrochemical test results showed that the samples treated 15 times showed the lowest corrosion current density in a 3.5 wt.% NaCl solution. This improved corrosion resistance is attributable to the refinement of the surface’s microstructure and the introduction of residual compressive stress. This study demonstrates the significant impact of HCPEB irradiation on the regulation of the properties of Ag-10La_0.7Sr_0.3CoO₃ composites. Full article

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14 pages, 4414 KB

Open AccessArticle

Advanced Laser–Plasma Diagnostics for a Modular High-Repetition-Rate Plasma Electron Accelerator

by Christian Greb, Esin Aktan, Roman Adam, Alex Dickson, Cédric Sire, Viktoria E. Nefedova, François Sylla, Rodrigo Lopez-Martens, Claus M. Schneider, Jérôme Faure and Markus Büscher

Instruments 2024, 8(3), 40; https://doi.org/10.3390/instruments8030040 - 14 Aug 2024

Cited by 1 | Viewed by 2474

Abstract

We present a laser–plasma electron accelerator module designed to be driven by high-repetition-rate lasers for industrial applications of laser-driven electron beams. It consists of a single vacuum chamber containing all the necessary components for producing, optimizing, and monitoring electron beams generated via laser [...] Read more.

We present a laser–plasma electron accelerator module designed to be driven by high-repetition-rate lasers for industrial applications of laser-driven electron beams. It consists of a single vacuum chamber containing all the necessary components for producing, optimizing, and monitoring electron beams generated via laser wakefield acceleration in a gas jet when driven by a suitable laser. The core methods in this paper involve a comprehensive metrological assessment of the driving laser by rigorous temporal laser pulse characterization and contrast measurements, supplemented by detailed spatiotemporal distribution analyses of the laser focus. Results demonstrate the good stability and reproducibility of the laser system, confirming its suitability for advanced scientific and industrial applications. We further demonstrate the functionality of the laser–plasma accelerator module diagnostics, perform target density characterizations, and time-resolved laser–plasma shadowgraphy. Current limitations of the set-up preventing first electron acceleration are analyzed and an outlook for future experiments is given. Our work is a first step towards the wide dissemination of fully integrated laser–plasma accelerator technology. Full article

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14 pages, 7188 KB

Open AccessArticle

Microstructure and Properties of TiN/TiCN/Al₂O₃/TiN Coating Enhanced by High-Current Pulsed Electron Beam

by Feiyu Ge, Ziteng Xia, Haoming Yuan, Siyang Guo, Zhijun Hu, Jintong Guan, Jie Cai, Qingfeng Guan and Peng Lyu

Coatings 2024, 14(4), 378; https://doi.org/10.3390/coatings14040378 - 23 Mar 2024

Cited by 1 | Viewed by 2697

Abstract

In this work, a TiN/TiCN/Al₂O₃/TiN coating deposited onto cemented carbide matrix by chemical vapor deposition was irradiated by high-current pulsed electron beam (HCPEB). The influence of pulse times on the phase composition, microstructure, and mechanical properties of the coating [...] Read more.

In this work, a TiN/TiCN/Al₂O₃/TiN coating deposited onto cemented carbide matrix by chemical vapor deposition was irradiated by high-current pulsed electron beam (HCPEB). The influence of pulse times on the phase composition, microstructure, and mechanical properties of the coating investigated. The results showed that no new phase was produced, the grain size of the coating surface was refined, the surface became flat, and the surface roughness decreased after HCPEB treatment. The TiN/TiCN/Al₂O₃/TiN coating presented a smooth surface with good mechanical performance after HCPEB. A maximum hardness was obtained after 15 pulses, and the 15-pulse irradiated coating showed better wear resistance. The improvement in the coating’s performance after irradiation was mainly attributed to the formation of grain refinement and crystal defects, as well as the change of stress field inside the coating. The objective of this study was to evaluate the potential of HCPEB modification in the preparation of high-performance coating by analyzing the microstructure and property of coating under different pulses. Full article

(This article belongs to the Section Surface Characterization, Deposition and Modification)

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20 pages, 4928 KB

Open AccessEditor’s ChoiceReview

A Tutorial on the One-Dimensional Theory of Electron-Beam Space-Charge Effect and Steady-State Virtual Cathode

by Weihua Jiang

Plasma 2024, 7(1), 29-48; https://doi.org/10.3390/plasma7010003 - 5 Jan 2024

Cited by 3 | Viewed by 3203

Abstract

The space-charge effects of pulsed high-current electron beams are very important to high-power particle beam accelerators and high-power microwave devices. The related physical phenomena have been studied for decades, and a large number of informative publications can be found in numerous scientific journals [...] Read more.

The space-charge effects of pulsed high-current electron beams are very important to high-power particle beam accelerators and high-power microwave devices. The related physical phenomena have been studied for decades, and a large number of informative publications can be found in numerous scientific journals over many years. This review article is aimed at systematically summarizing most of the previous findings in a logical manner. Using a normalized one-dimensional mathematical model, analytical solutions have been obtained for the space-charge-limited current of both planar diode and drifting space. In addition, in the case of a beam current higher than the space-charge-limited current, the virtual cathode behavior and beam current reflection are quantitively studied. Furthermore, the criteria of steady-state virtual cathode formation are investigated, which leads to the physical understanding of the unstable nature of the virtual cathode. This review article is expected to serve as an integrated source of related information for young researchers and students working on high-power microwaves and pulsed particle beams. Full article

(This article belongs to the Special Issue Latest Review Papers in Plasma Science 2023)

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17 pages, 1714 KB

Open AccessArticle

Shaping Micro-Bunched Electron Beams for Compact X-ray Free-Electron Lasers with Transverse Gradient Undulators

by River R. Robles and James B. Rosenzweig

Instruments 2023, 7(4), 35; https://doi.org/10.3390/instruments7040035 - 26 Oct 2023

Viewed by 2265

Abstract

Laser-modulator-based micro-bunching of electron beams has been applied to many novel operating modes of X-ray free-electron lasers from harmonic generation to attosecond pulse production. Recently, it was also identified as a key enabling technology for the production of a compact XFEL driven by [...] Read more.

Laser-modulator-based micro-bunching of electron beams has been applied to many novel operating modes of X-ray free-electron lasers from harmonic generation to attosecond pulse production. Recently, it was also identified as a key enabling technology for the production of a compact XFEL driven by a relatively low-energy beam. In traditional laser modulator schemes with low-energy and high-current bunches, collective effects limit the possible working points that can be employed, and thus it is difficult to achieve optimal XFEL performance. We propose to utilize transverse longitudinal coupling in a transverse gradient undulator (TGU) to shape micro-bunched electron beams so as to optimize their performance in a compact X-ray free-electron laser. We show that a TGU added to a conventional laser modulator stage enables much more flexibility in the design, allowing one to generate longer micro-bunches less subject to slippage effects and even lower the slice emittance of the micro-bunches. We present a theoretical analysis of laser-based micro-bunching with an added TGU, simulation of compression with collective effects in such systems, and finally XFEL simulations demonstrating the gains in peak power enabled by the TGU. Although we focus on the application to compact XFELs, what we propose is a general phase space manipulation that may find utility in other applications as well. Full article

(This article belongs to the Special Issue Selected Papers from the Workshop on Physics and Applications of High Brightness Beams)

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34 pages, 6363 KB

Open AccessReview

Computational and Experimental Modeling in Magnetoplasma Aerodynamics and High-Speed Gas and Plasma Flows (A Review)

by Victor V. Kuzenov, Sergei V. Ryzhkov and Aleksey Yu. Varaksin

Aerospace 2023, 10(8), 662; https://doi.org/10.3390/aerospace10080662 - 25 Jul 2023

Cited by 40 | Viewed by 3700

Abstract

This paper provides an overview of modern research on magnetoplasma methods of influencing gas-dynamic and plasma flows. The main physical mechanisms that control the interaction of plasma discharges with gaseous moving media are indicated. The ways of organizing pulsed energy input, characteristic of [...] Read more.

This paper provides an overview of modern research on magnetoplasma methods of influencing gas-dynamic and plasma flows. The main physical mechanisms that control the interaction of plasma discharges with gaseous moving media are indicated. The ways of organizing pulsed energy input, characteristic of plasma aerodynamics, are briefly described: linearly stabilized discharge, magnetoplasma compressor, capillary discharge, laser-microwave action, electron beam action, nanosecond surface barrier discharges, pulsed spark discharges, and nanosecond optical discharges. A description of the physical mechanism of heating the gas-plasma flow at high values of electric fields, which are realized in high-current and nanosecond (ultrafast heating) electric discharges, is performed. Methods for magnetoplasma control of the configuration and gas-dynamic characteristics of shock waves arising in front of promising and advanced aircraft (AA) are described. Approaches to the control of quasi-stationary separated flows, laminar–turbulent transitions, and static and dynamic separation of the boundary layer (for large PA angles of attack) are presented. Full article

(This article belongs to the Special Issue High Speed Flows: Measurements & Simulations)

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8 pages, 1798 KB

Open AccessCommunication

Low Trapping Effects and High Blocking Voltage in Sub-Micron-Thick AlN/GaN Millimeter-Wave Transistors Grown by MBE on Silicon Substrate

by Elodie Carneiro, Stéphanie Rennesson, Sebastian Tamariz, Kathia Harrouche, Fabrice Semond and Farid Medjdoub

Electronics 2023, 12(13), 2974; https://doi.org/10.3390/electronics12132974 - 6 Jul 2023

Cited by 3 | Viewed by 3408

Abstract

In this work, sub-micron-thick AlN/GaN transistors (HEMTs) grown on a silicon substrate for high-frequency power applications are reported. Using molecular beam epitaxy, an innovative ultrathin step-graded buffer with a total stack thickness of 450 nm enables one to combine an excellent electron confinement, [...] Read more.

In this work, sub-micron-thick AlN/GaN transistors (HEMTs) grown on a silicon substrate for high-frequency power applications are reported. Using molecular beam epitaxy, an innovative ultrathin step-graded buffer with a total stack thickness of 450 nm enables one to combine an excellent electron confinement, as reflected by the low drain-induced barrier lowering, a low leakage current below 10 µA/mm and low trapping effects up to a drain bias V_DS = 30 V while using sub-150 nm gate lengths. As a result, state-of-the-art GaN-on-silicon power performances at 40 GHz have been achieved, showing no degradation after multiple large signal measurements in deep class AB up to V_DS = 30 V. Pulsed-mode large-signal characteristics reveal a combination of power-added efficiency (PAE) higher than 35% with a saturated output power density (P_OUT) of 2.5 W/mm at V_DS = 20 V with a gate-drain distance of 500 nm. To the best of our knowledge, this is the first demonstration of high RF performance achieved with sub-micron-thick GaN HEMTs grown on a silicon substrate. Full article

(This article belongs to the Section Microelectronics)

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13 pages, 5242 KB

Open AccessArticle

Effect of High Current Pulsed Electron Beam (HCPEB) on the Organization and Wear Resistance of CeO₂-Modified Al-20SiC Composites

by Lei Wang, Bo Gao, Yue Sun, Ying Zhang and Liang Hu

Materials 2023, 16(13), 4656; https://doi.org/10.3390/ma16134656 - 28 Jun 2023

Cited by 4 | Viewed by 1648

Abstract

This paper investigates the joint effect of high current pulsed electron beam (HCPEB) and denaturant CeO₂ on improving the microstructure and properties of Al-20SiC composites prepared by powder metallurgy. Grazing Incidence X-ray Diffraction (GIXRD) results indicate the selective orientation of aluminum grains, [...] Read more.

This paper investigates the joint effect of high current pulsed electron beam (HCPEB) and denaturant CeO₂ on improving the microstructure and properties of Al-20SiC composites prepared by powder metallurgy. Grazing Incidence X-ray Diffraction (GIXRD) results indicate the selective orientation of aluminum grains, with Al(111) crystal faces showing selective orientation after HCPEB treatment. Casting defects of powder metallurgy were eliminated by the addition of CeO₂. Scanning electron microscopy (SEM) results reveal a more uniform distribution of hard points on the surface of HCPEB-treated Al-20SiC-0.3CeO₂ composites. Microhardness and wear resistance of the Al-20SiC-0.3CeO₂ composites were better than those of the Al matrix without CeO₂ addition at the same number of pulses. Sliding friction tests indicate that the improvement of wear resistance is attributed to the uniform dispersion of hard points and the improvement of microstructure on the surface of the matrix after HCPEB irradiation. Overall, this study demonstrates the potential of HCPEB and CeO₂ to enhance the performance of Al-20SiC composites. Full article

(This article belongs to the Special Issue Experimental Testing, Manufacturing and Numerical Modelling of Composite and Sandwich Structures)

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9 pages, 2081 KB

Open AccessArticle

The Particle-Tracking Simulation of a New Photocathode RF Gun in the Free-Electron Laser Facility, KU-FEL

by Yuhao Zhao, Heishun Zen and Hideaki Ohgaki

Particles 2023, 6(2), 638-646; https://doi.org/10.3390/particles6020037 - 6 Jun 2023

Viewed by 1836

Abstract

A project is underway that aims to generate attosecond pulses via high-harmonic generation in rare gases, driven by extremely short and highly intense pulses from free-electron-laser oscillators. For this purpose, it has been planned that a new photocathode RF gun, dedicated to high-bunch-charge [...] Read more.

A project is underway that aims to generate attosecond pulses via high-harmonic generation in rare gases, driven by extremely short and highly intense pulses from free-electron-laser oscillators. For this purpose, it has been planned that a new photocathode RF gun, dedicated to high-bunch-charge operation, will be installed at the KU-FEL (Kyoto University Free Electron Laser) oscillator facility. In this study, RF guns with two different structures (1.6-cell and 1.4-cell) were compared, from the perspective of exploring the possibility of introducing bunch-interval modulation, which is important for achieving high extraction efficiency in the FEL oscillator. As a result, it was confirmed that the introduction of bunch-phase modulation would be possible only in the case of the 1.6-cell RF gun. After the structure of the RF gun was decided on, particle-tracking simulations were performed, to study the electron-beam parameters using the 1.6-cell RF gun and 1 nC bunch charge. The results showed that we could obtain the peak current of 1 kA without a large degradation of the other parameters. Full article

(This article belongs to the Special Issue Generation and Application of High-Power Radiation Sources)

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