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Developing New Materials for Electron Beam Melting: Experiences and Challenges
摘要： Lack of industrially available materials for additive manufacturing (AM) of metallic materials along with the promises of materials with improved or unique properties provides a strong drive for developing new process/material combinations. As powder bed technologies for metallic materials are relatively new to the market, and to some extent are only maturing, developers of new process/material combinations have certain challenges to overcome. Firstly, basic knowledge on the behavior of materials (even those well established for other applications) under extreme conditions of melting/solidification with beam-based AM methods is far from being adequate. Secondly, manufacturing of the equipment is up to date driven by industrial application, thus optimization of the AM machines for small test batches of powders is still belongs to research and development projects. Also, majority of the powder manufacturers are primarily driven by the market development, and even they are well aware of the demands imposed by the powder bed AM machines, availability of small test batches of adequate powders may be problematic or at least quite costly for the R&D oriented users. Present paper describes the experiences in developing new materials for EBM A2 machine by Arcam EBM, modified for operating with powder batches of 100-200 ml and less. In particular it discusses achievements and challenges of working with powders from different materials with specifications far beyond the range suggested by machine manufacturer. Also it discusses the possibility of using blended rather than pre-alloyed powders for achieving both composite-like and alloyed materials in the same part by steering electron beam energy deposition strategy.
关键词： Electron Beam Melting,material development,composite materials,Additive Manufacturing,blended powders,in situ alloying
更新于2025-09-23 15:23:52
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A Facile Route for NLO Materials: Three-Site Alivolent Substitution Involving One Cation and Two Anions
摘要： Two mixed-metal gallium iodate fluorides, namely, α- and β-Ba2[GaF4(IO3)2](IO3) (1 and 2) have been obtained by the aliovalent substitutions of α- and β-Ba2[VO2F2(IO3)2](IO3) (3 and 4) involving one cationic and two anionic sites. Both of them display large SHG signals (~6 × KDP), large energy bandgaps (4.61 and 4.35 eV), wide transmittance ranges (~0.27-12.5 μm), and large relevant LDTs (29.7 × and 28.3 × AgGaS2, respectively), which indicates that 1 and 2 are potential second-order NLO materials in ultraviolet to mid-infrared. Our studies propose that three-site aliovalent substitution is a facile route for the discovery of good NLO materials.
关键词： aliovalent substitution,hydrothermal synthesis,NLO material,mixed-metal iodate fluoride,theoretical calculations
更新于2025-09-23 15:23:52
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[Advanced Structured Materials] Materials Design and Applications II Volume 98 || Orientation of the Digital Model for SLA 3D Printing and Its Influence on the Accuracy of the Manufactured Physical Objects for Micro- and Nano Technologies
摘要： In modern mechanical engineering, there is increased need to find solutions for fast manufacturing of real prototypes. One of these is the fast-growing up-to-date CAD/CAM/CAE system enabling to create digital prototypes. Using CAD systems the conceptual design is analyzed and tested before producing the real prototype. This reduces the compliance costs for manufacturing of the physical models and tooling as well as the production time of the prototype is lessened several times. With the development of technology, and especially in medicine, it is necessary to produce prototypes that can be obtained relatively quickly and meet the requirements of accuracy. Rapid prototyping technologies have such capabilities that they can reproduce digital models with their manufacturer’s precision. To determine the accuracy of printing, a SLA system is used. To determine the accuracy of printing, a SLA system is used. One of the peculiarities of making a detail by this method is the appearance of distortions in the initial stage of construction at large rectilinear plots. In order to determine the minimum printing deviations, a strategy for printing prototype models at a different slope of 0°–90° was used. Patterns are made with coordinate networks, enabling post-print deviations to be evaluated by matching the digital model. The present study will be useful in developing prototype models for micro and nanotechnology in mechanical engineering and medicine, providing a solution for their optimal location with minimal deviations.
关键词： CAD system,Material for casting,Photopolymer,Micro model,SLA 3D printing
更新于2025-09-23 15:23:52
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Approach to Inversion Design of Dielectric Material Based on the First-Principle
摘要： The ?rst-principle is an e?ective method for the material property calculation. One inversion design idea of dielectric material based on the ?rst-principle was put forward. In this kind of material design thought, the speci?c demanded dielectric property of material is the starting point of the whole design course. The atomic structure characteristic of the material is solved using the inversion model based on the ?rst-principle. And the key issues needing researching were discussed, these problems were quantized structure of electromagnetic and optic ?eld, the quantized polarization theory of dielectric material, the uniform calculation method of dielectric property and the dielectric material inversion model.
关键词： Dielectric material,First-principle,Dielectric property,Inversion design
更新于2025-09-23 15:23:52
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A high gain miniaturised patch antenna with an epsilon near zero superstrate
摘要： In this paper, a miniaturized patch antenna (MPA) with Zero Index Metamaterial (ZIM) as Superstrate at 518MHz is designed and fabricated. The proposed method is utilized for retrieving the effective properties, i.e., impedance, refractive index, as well as the permittivity, and permeability of the unit cell. We have investigated the effect of distance between the antenna and the Superstrate on performance of the antenna. Moreover, the performance of the antenna is evaluated by both simulations and measurements. The results of our study have shown more directional and higher gain patch antennas. Also, a good agreement between the measured and the simulation values is found. It is demonstrated that the gain of antenna, having the ZIM Superstrate, is much higher compared to the one without the ZIM superstrate. Furthermore, the mean value of the gain for the proposed Metamaterial antenna (which is Superstrate-based) is considerably improved from -1.9 to 3.97 dBi comparing to the patch antenna alone. In fact, the directivity of the antenna is dramatically improved based on the zero refraction properties of the Metamaterial.
关键词： Low profile,Metamaterial,Epsilon near zero material,High gain antenna
更新于2025-09-23 15:23:52
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High quality factor cold sintered Li2MoO4BaFe12O19 composites for microwave applications
摘要： Ceramics-ceramic composites (1-x)Li2MoO4-xBaFe12O19 (LMO-BF12, 0.00≤x≤0.15) have been cold sintered at 120oC and their structure and properties characterized. X-ray diffraction, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) confirmed that compositions were dual phase and had a dense microstructure. Composites in the xBF12-(1-x)LMO (0.0≤x≤0.15) series resonated at MW frequencies (~6GHz) with 5.6≤e r≤5.8 and Qf =16,000-22,000 GHz, despite the black colour of compositions with x > 0. The permeability of the composites was measured in the X band (~8 GHz) and showed an increase from 0.94 (x=0.05) to 1.02 (x=0.15). Finite element modelling revealed that the volume fraction of BF12 dictates the conductivity of the material, with a percolation threshold at 10 vol.% BF12 but changes in e r as a function of x were readily explained using a series mixing model. In summary, these composites are considered suitable for the fabrication of dual mode or enhanced bandwidth microstrip patch antennas.
关键词： Finite element modeling (FEM),Composite,Cold sintering process,Dielectric,Ceramic material
更新于2025-09-23 15:23:52
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A new non-centrosymmetric Chlorobismuthate(III) hybrid material: Crystal structure, optical properties and antibacterial study
摘要： As part of our interest in organic-inorganic metallate complexes, we had prepared a novel non-centrosymmetric chlorobismuthate (III) compound with the chemical formula (C6H7NCl)3 [BiCl6]$H2O, by slow evaporation method at room temperature. It was characterized by single crystal X-ray diffraction (SCXRD), X-ray powder diffraction (PXRD), spectroscopic measurements, thermal study, Hirshfeld surface analysis, DFT investigation, and antimicrobial activity. A preliminary SCXRD structural analysis revealed that the compound crystallizes in the Orthorhombic system (P212121 space group) with the following unit cell parameters a ? 7.3432 (1) ?, b ? 13.8257 (2) ? and c ? 28.2140 (5) ? with Z ? 4 and V ? 2864.42 (8) ?3. The examination of the structure shows that its atomic arrangement can be described as inorganic [BiCl6]3- units isolated from each other by the organic cations and the co-crystallized water molecules. The cohesion between these entities is performed via the NeH/Cl, NeH/O, CeH/O, CeH/Cl, and OeH/Cl hydrogen bonding interactions between the 4-dichloroanilinium cations, the [BiCl6]3- anions and water molecules forming a 3D network. The Hirshfeld surface calculation was conducted to investigate: intermolecular interactions, associated 2D ?ngerprint plots, and enrichment ratio, indicating the relative contribution of these interactions in the crystal structure quantitatively. Thermal analysis reveals the decomposition of the compound at 180 (cid:2)C. The quantum mechanical calculations such as geometry optimization, vibrational frequencies, simulated UVeVisible spectrum, FMOs analysis were made together with the experimental studies. Furthermore, the new synthesized compound was screened for its antibacterial activity. Results revealed that it has the most effective activity against all the tested bacteria compared to the amine alone and to the BiOCl.
关键词： Hirshfeld surface analysis,Hybrid material,DFT calculations,Hexachlorobismuthate(III),X-ray diffraction,Antimicrobial activity
更新于2025-09-23 15:23:52
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[IEEE 2018 International Multi-Conference on Industrial Engineering and Modern Technologies (FarEastCon) - Vladivostok, Russia (2018.10.3-2018.10.4)] 2018 International Multi-Conference on Industrial Engineering and Modern Technologies (FarEastCon) - Experimental Study of the Stress-Strain State Features of Outlet Guide Vane Made From Polymer Composite Material Using Fiber Optic Sensors
摘要： An estimation technique for the stress-strain state of the outlet guide vane design of an aircraft propulsion system made of polymer composite materials (PCM) using fiber-optic sensors is proposed. Fiber-optic sensors allow creating details with the possibility of self-diagnosis and forecasting the resource of work. This issue is particularly relevant when using PCM in highly loaded aircraft engine elements. The object of the study is the outlet guide vane (OGV) made of an equally strong carbon cloth on an epoxy binder. The tests were carried out on a universal servo-hydraulic machine. The data from fiber-optic sensors was carried out using an interrogator ASTRO X327. The comparison of the experiment and the numerical calculation were performed using the software package ANSYS.
关键词： polymer composite material,fiber optic sensors,numerical calculations,stress-strain state
更新于2025-09-23 15:23:52
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[IEEE 2018 International Conference on Applied Engineering (ICAE) - Batam, Indonesia (2018.10.3-2018.10.4)] 2018 International Conference on Applied Engineering (ICAE) - Epoxy Adhesive as Die Attach Material in Semiconductor Packaging: A Review
摘要： Semiconductor packaging generally includes many steps such as wafer mounting, wafer dicing, die attach or die bonding, wire bonding, molding, plating, marking, and trim form. Die attach process is one of the crucial process in electronics packaging or semiconductor packaging. So, the die attaches material is an important part of this process. Die attach materials are commonly divided into some categories. The categories cover high and low-temperature application. Some kinds of die attach materials are alternative resins, epoxy adhesive, soft soldering, die attach solders and silver-glass material. In this study focuses to review epoxy adhesive material in die attach process.
关键词： epoxy adhesive material,die attach,semiconductor packaging,material characterization
更新于2025-09-23 15:22:29
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Case Study of Empirical Beam Hardening Correction Methods for Dimensional X-ray Computed Tomography Using a Dedicated Multi-material Reference Standard
摘要： This paper presents a case study of two selected beam hardening correction methods and their effects on dimensional measurements of multi-material objects. The methods under test are empirical cupping correction (ECC) and empirical dual energy calibration (EDEC). These methods were originally developed for medical applications and their potential for the reduction of artefacts is typically only analysed based on grey value images. For testing and benchmarking of the mentioned methods for dimensional metrology, a dedicated multi-material reference standard—a multi-material hole cube—is used. This reference standard was originally developed for acceptance testing of CT systems. This paper shows a second application of this standard. The reference standard has been calibrated by tactile measurements to assess centre–centre distance errors as well as patch-based bidirectional length measurement errors on beam hardening corrected data and on uncorrected data. For the application of the method also to industrial multi-material scenarios, slight modifications of the ECC method are proposed. Practical aspects of both the ECC and the EDEC approaches as well as measurement results are analysed and discussed in detail. ECC was able to significantly improve dimensional measurements and was especially able to reduce extreme errors occurring in particular in multi-material scenarios by a factor of more than 4. EDEC, the dual-energy approach, reduced grey value inhomogeneities caused by artefacts even more. Its performance for dimensional measurements was however a little worse than ECC. EDEC data resulted in a slightly larger total range of residual measurement errors, mainly due to an elevated noise level.
关键词： Beam hardening correction,Industrial computed tomography,Multi-material measurements,Material influence,Dimensional metrology
更新于2025-09-23 15:22:29