scholarly journals Оптимизация анодной мембраны с прострельной мишенью в системе источников мягкого рентгеновского излучения для проведения процессов рентгеновской нанолитографии

2020 ◽  
Vol 90 (11) ◽  
pp. 1789
Author(s):  
П.Ю. Глаголев ◽  
Г.Д. Демин ◽  
Г.И. Орешкин ◽  
Н.И. Чхало ◽  
Н.А. Дюжев
Keyword(s):  
High Hardness ◽  
Operating Characteristics ◽  
Control Electrode ◽  
X Ray ◽  
Voltage Difference ◽  
Optimal Distance ◽  
Additional Control ◽  
Electrode Space ◽  
Anode Electrode ◽  
Electrostatic Deflection

In this paper, we propose a method for optimizing the design and composition of the anode membrane with a transmission-type target as part of a system of soft X-ray sources based on field-emission triodes for performing tasks in the field of X-ray nanolithography. It allows to prevent the degradation of the operating characteristics of the system when significant electrostatic deformation of the anode occurs under the influence of a control electric field in the inter-electrode space of the triodes. For this purpose, the inclusion of an additional control electrode in the system design is considered, which makes it possible to compensate for the deformation of the anode membrane to an acceptable level and thereby stabilize the operation of X-ray sources. A numerical model of the electrostatic deflection of the anode assembly in a modified design is developed, based on which the optimal composition and geometric parameters of the anode membrane with a compensating electrode are determined. In particular, the optimal distance between the anode membrane in the initial (undeformed) state and the compensating electrode was found (equal to 5 μm), at which a minimum voltage difference (about 1.15 kV) should be applied to these electrodes to prevent critical deflection of the membrane (0.72 μm with a membrane radius of 750 µm). It is also shown that, due to their extremely high hardness (>80 GPa), diamond-like films are the most promising material for the anode electrode. The results obtained can also be useful for the development of miniature X-ray generation devices for various applications.

Hardening of Selective Laser Melted M2 Steel

2021 ◽  
Author(s):  
Mei Yang ◽  
Yishu Zhang ◽  
Haoxing You ◽  
Richard Smith ◽  
Richard D. Sisson
Keyword(s):  
Heat Treatment ◽  
High Speed ◽  
Cutting Tools ◽  
High Speed Steel ◽  
High Hardness ◽  
Steel Part ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Near Net Shape

Abstract Selective laser melting (SLM) is an additive manufacturing technique that can be used to make the near-net-shape metal parts. M2 is a high-speed steel widely used in cutting tools, which is due to its high hardness of this steel. Conventionally, the hardening heat treatment process, including quenching and tempering, is conducted to achieve the high hardness for M2 wrought parts. It was debated if the hardening is needed for additively manufactured M2 parts. In the present work, the M2 steel part is fabricated by SLM. It is found that the hardness of as-fabricated M2 SLM parts is much lower than the hardened M2 wrought parts. The characterization was conducted including X-ray diffraction (XRD), optical microscopy, Scanning Electron Microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS) to investigate the microstructure evolution of as-fabricated, quenched, and tempered M2 SLM part. The M2 wrought part was heat-treated simultaneously with the SLM part for comparison. It was found the hardness of M2 SLM part after heat treatment is increased and comparable to the wrought part. Both quenched and tempered M2 SLM and wrought parts have the same microstructure, while the size of the carbides in the wrought part is larger than that in the SLM part.

scholarly journals Semisolid State Sintering Behavior of Aluminum–Stainless Steel 316L Composite Materials by Powder Metallurgy

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1473 ◽  
Author(s):  
Kwangjae Park ◽  
Dasom Kim ◽  
Kyungju Kim ◽  
Seungchan Cho ◽  
Kenta Takagi ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Intermetallic Compounds ◽  
Vickers Hardness ◽  
Raw Materials ◽  
High Hardness ◽  
Engineering Industry ◽  
Sintering Behavior ◽  
Semisolid State ◽  
Stainless Steel 316L ◽  
X Ray

Aluminum (Al)-stainless steel 316L (SUS316L) composites were successfully fabricated by the spark plasma sintering process (SPS) using pure Al and SUS316L powders as raw materials. The Al-SUS316L composite powder comprising Al with 50 vol.% of SUS316L was prepared by a ball milling process. Subsequently, it was sintered at 630 °C at a pressure of 200 MPa and held for 5 min in a semisolid state. The X-ray diffraction (XRD) patterns show that intermetallic compounds such as Al13Fe4 and AlFe3 were created in the Al-SUS316L composite because the Al and SUS316L particles reacted together during the SPS process. The presence of these intermetallic compounds was also confirmed by using XRD, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and EDS mapping. The mechanical hardness of the Al-SUS316L composites was analyzed by a Vickers hardness tester. Surprisingly, the Al-SU316L composite exhibited a Vickers hardness of about 620 HV. It can be concluded that the Al-SUS316L composites fabricated by the SPS process are lightweight and high-hardness materials that could be applied in the engineering industry such as in automobiles, aerospace, and shipbuilding.

scholarly journals Determination of Calcium in Wolframite Concentrates by Fluorescent X-Ray Spectrography

1958 ◽  
Vol 2 ◽  
pp. 313-332 ◽  
Author(s):  
William J. Campbell ◽  
John W. Thatcher
Keyword(s):  
Gas Flow ◽  
Position Effect ◽  
Pulse Height ◽  
Calcium Content ◽  
Accurate Method ◽  
Counting Efficiency ◽  
Matrix Composition ◽  
Operating Characteristics ◽  
X Ray ◽  
Small Depth

AbstractThe purpose of this investigation was to develop a rapid, accurate method of analysis for small amounts of calcium in wolframite concentrates. This analysis is necessary to determine if wolframite concentrates meet the U. S. National Stockpile Specification P-57R2, which limits the calcium content to 0.2 per cent.Because of the small depth of sample analyzed in fluorescent x-ray spectrography the calcium Kα line intensity was found to be a function of the chemical composition of the calcium-bearing particle as well as the matrix composition. This particle-conn position effect was particularly important in this analysis because the calcium may be present as a carbonate, tungstate, phosphate, etc. Three methods of sample preparation were found to eliminate the variation of calcium Kα intensity with mineralogical occurrences: (1) Reduction in particle size by extensive grinding, (2) chemical fusion wtli sodium carbonate, and (3) solution of the calcium by an add.Determinations by all three procedures are believed to be accurate to within ± 5 per cent for more than 0.30 per cent calcium and ± 10 per cent at the 0.1-per cent level. The lower limit of detectability is in the order of 0.005-0.01 per cent.The operating characteristics of a gas-flow proportional counter used in conjunction with a pulse-height analyzer were studied in detail. This detector was found to have a high counting efficiency for calcium Ka radiation, to have a low counting efficiency for overlapping higher order radiation and to have counting stability equivalent to Geiger tubes.

Microstructure and Hardness of Ni-Cr Porous Preform Reinforced Al-Based Composites by Low Infiltration Method

2011 ◽  
Vol 275 ◽  
pp. 251-254
Author(s):  
Hua Wei Rong ◽  
Cheol Hong Park ◽  
Won Jo Park ◽  
Han Ki Yoon
Keyword(s):  
Intermetallic Compounds ◽  
Rapid Development ◽  
High Hardness ◽  
Optical Microscope ◽  
Matrix Composites ◽  
X Ray Diffraction ◽  
Infiltration Process ◽  
Pressure Infiltration ◽  
X Ray ◽  
Infiltration Method

With the rapid development of aerospace and automobile industries, metal matrix composites (MMCs) have attracted much attention because of its excellent performance. In this paper, Ni-Cr/AC8A composites reinforced with porous Ni-Cr preform were manufactured by low pressure infiltration process, infiltration temperatures are 700oC~850oC. The microstructure and phase composition of composites were evaluated using optical microscope, X-ray diffraction (XRD) and electro-probe microanalysis (EPMA), It's found that they're intermetallic compounds generated in the composites. Recently, intermetallic compounds have attracted much attention as high-temperature material. We study the hardness of Ni-Cr/AC8A composites, the results show the Ni-Cr/AC8A composite has high hardness due to the intermetallic compounds exist.

Depth-dependent defect and residual stress distribution in magnetron sputtered MoN:Cu nanocomposite films by x-ray microdiffraction

2006 ◽  
Vol 977 ◽  
Author(s):  
Gang Chen ◽  
Dileep Singh ◽  
Osman Eryilmaz ◽  
Ali Erdemir ◽  
Jules Routbort ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
High Hardness ◽  
Residual Stress Distribution ◽  
Nanocomposite Films ◽  
Structure Property ◽  
Nanocrystalline Films ◽  
Low Friction ◽  
X Ray ◽  
Property Relations

AbstractWe have developed a synchrotron-based x-ray microdiffraction technique for measuring depth-resolved residual stress distribution in nanocrystalline films with submicron resolution [1]. In this study, we further refined this technique and applied it to low-friction and high-hardness Cu-doped MoN films. These magnetron sputtered nanocomposites films consist of MoN, Mo2N, and Cu phases, whose ratio depends on Cu concentration. By using the microdiffraction technique, we discovered that both the deviatoric and the hydrostatic components of the residual stresses depend on the film depth (Fig.1). The former indicates depth-dependent distribution of biaxial stresses, while the latter implies depth-dependent defect distribution, which also depends on Cu concentration. Thermal annealing of the nanocomposite film partially relives the stress, significantly reduces the lattice spacing, and eliminates the defect gradients. These results suggest that interstitial N may play an important role in the lattice expansion and the defect gradients formed during the non-equilibrium sputtering process. Our study provides fresh insights into understanding the structure-property relations in the magnetron sputtered MoN:Cu nanocomposites films.

Formation of boride layers on a commercially pure Ti surface produced via powder metallurgy

2021 ◽  
Vol 112 (4) ◽  
pp. 303-307
Author(s):  
Yavuz Kaplan ◽  
Mehmet Gülsün ◽  
Sinan Aksöz
Keyword(s):  
Powder Metallurgy ◽  
Substrate Surface ◽  
High Hardness ◽  
Titanium Boride ◽  
Boride Layer ◽  
Powder Metallurgy Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Commercially Pure ◽  
Boriding Process

Abstract In this study, powder metallurgy was applied in a furnace atmosphere to form titanium boride layers on a commercially pure Ti surface. Experiments were carried out using the solid-state boriding method at 900 °C and 1000°C for 12 h and 24 h. Samples were produced by pressing the commercially pure Ti powders under 870 MPa. The sintering process required by the powder metallurgy method was carried out simultaneously with the boriding process. Thus, the sintering and boriding were performed in one stage. The formation of the boride layer was investigated by field emission scanning electron microscopy, optical-light microscopy, X-ray diffraction, and elemental dispersion spectrometry analyses. In addition, microhardness measurements were performed to examine the effect of the boriding process on hardness. The Vickers microhardness of the boronized surface reached 1773 HV, which was much higher than the 150 HV hardness of the commercially pure Ti substrate. The X-ray diffraction analysis showed that the boriding process had enabled the formation of TiB and TiB2 on the powder metallurgy Ti substrate surface. Consequently, the production of Ti via powder metallurgy is a potentially cost-effective alternative to the conventional method, and the boriding process supplies TiB and TiB2 that provide super-high hardness and excellent wear and corrosion resistance.

Microstructure and Mechanical Properties of Fe-Cu-Ni Sinters Prepared by Ball Milling and Hot Pressing

2020 ◽  
Vol 405 ◽  
pp. 379-384
Author(s):  
Joanna Borowiecka-Jamrozek ◽  
Jan Lachowski
Keyword(s):  
Mechanical Properties ◽  
Hot Pressing ◽  
High Hardness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Powder Composition ◽  
Microstructure And Mechanical Properties ◽  
Static Tensile ◽  
Iron Based ◽  
Surface Observations

The main purpose of this work was to determine the effect of the powder composition on the microstructure and properties of iron-based sinters used as a matrix in diamond tools. The Fe-Cu-Ni sinters obtained from a mixture of ground powders were used for experiments. The influence of manufacturing process parameters on the microstructure and mechanical properties of sinters was investigated. Sintering was performed using hot-pressing technique in a graphite mould. The investigations of obtained sinters included: density, hardness, static tensile test, X-ray diffraction analysis, microstructure and fracture surface observations. The obtained results indicate that the produced sinters have good plasticity and relatively high hardness.

Comparative evaluation of corrosion effects between nanocrystalline silver alloy and tradition gold stacks using spring probe contacts

2019 ◽  
Author(s):  
Vinay Budhraja ◽  
Jarvis Stirn ◽  
Eric Hallstrom ◽  
Brian Lutz ◽  
Michael Brennan
Keyword(s):  
Copper Alloy ◽  
Comparative Evaluation ◽  
High Hardness ◽  
The Body ◽  
Nano Materials ◽  
Silver Alloy ◽  
X Ray ◽  
Viable Solution ◽  
Materials Research ◽  
Salt Fog

Although silver is evaluated as an alternative of gold, it is more prone to tarnishing, oxidization and corrosion. Recent advancements in nano materials research resulted in a nanocrystalline silver alloy which has several advantages like high hardness, thermal stability, non-coarsen with age, hence a viable solution for connector applications. In this work, the performance of nanocrystalline silver alloy against corrosion was studied. Two different set of spring probes were electroplated on inner and outer regions and tested using force deflection resistance (FDR), life cycle test (LCT), SEM, EDS and X-Ray CT scan. First set of spring probes were electroplated with nanocrystalline silver alloy, nanocrystalline Ni-W, Ni sulfamate and Ni strike with thicknesses of 2.4 µm, 1.8 µm, 2.0 µm and 0.5 µm respectively. Second set of spring probes were electroplated with Gold, Ni sulfamate and Ni strike with thicknesses of 0.9 µm 1.9 µm and 0.5 µm respectively. The body of spring probes was made up of copper alloy. This work reports the changes in electrical, mechanical and material properties of nanocrystalline silver alloy and gold stacks after reliability operations like humidity test for 24 hours and 96 hours, porosity test for 60 mins and salt-fog test for 24 hours.

scholarly journals Detection of COVID-19 from Chest X-Ray Images Using Convolutional Neural Networks

2020 ◽  
Vol 25 (6) ◽  
pp. 553-565 ◽  
Author(s):  
Boran Sekeroglu ◽  
Ilker Ozsahin
Keyword(s):  
Machine Learning ◽  
Neural Networks ◽  
Deep Learning ◽  
Convolutional Neural Networks ◽  
Statistical Data ◽  
Area Under The Curve ◽  
Operating Characteristics ◽  
X Ray ◽  
Life Saving ◽  
Chest X Ray

The detection of severe acute respiratory syndrome coronavirus 2 (SARS CoV-2), which is responsible for coronavirus disease 2019 (COVID-19), using chest X-ray images has life-saving importance for both patients and doctors. In addition, in countries that are unable to purchase laboratory kits for testing, this becomes even more vital. In this study, we aimed to present the use of deep learning for the high-accuracy detection of COVID-19 using chest X-ray images. Publicly available X-ray images (1583 healthy, 4292 pneumonia, and 225 confirmed COVID-19) were used in the experiments, which involved the training of deep learning and machine learning classifiers. Thirty-eight experiments were performed using convolutional neural networks, 10 experiments were performed using five machine learning models, and 14 experiments were performed using the state-of-the-art pre-trained networks for transfer learning. Images and statistical data were considered separately in the experiments to evaluate the performances of models, and eightfold cross-validation was used. A mean sensitivity of 93.84%, mean specificity of 99.18%, mean accuracy of 98.50%, and mean receiver operating characteristics–area under the curve scores of 96.51% are achieved. A convolutional neural network without pre-processing and with minimized layers is capable of detecting COVID-19 in a limited number of, and in imbalanced, chest X-ray images.

Microstructure of TiC/Amorphous Hydrocarbon Nanocomposite Coatings

2000 ◽  
Vol 6 (S2) ◽  
pp. 440-441
Author(s):  
D. M. Cao ◽  
J. C. Jiang ◽  
B. Feng ◽  
W. J. Meng
Keyword(s):  
Inductively Coupled Plasma ◽  
High Hardness ◽  
Ceramic Surface ◽  
Edge Structure ◽  
X Ray ◽  
Inductively Coupled ◽  
Transmission Electron ◽  
Wide Range ◽  
Mechanical Components ◽  
X Ray Absorption

Application of an appropriate ceramic surface coating to mechanical components such as bearings and gears can provide longer life and increased performance reliability. Metal-containing hydrocarbon (Me-C:H) coatings possess high hardness, together with low friction and low wear rate. They have also been suggested to adhere better to metallic substrates. This combination of attractive mechanical/tribological properties makes Me-C:H coatings potentially useful for surface modification of a wide range of mechanical components.Using the technique of inductively coupled plasma (ICP) assisted vapor deposition[1], we have synthesized Ti-containing hydrocarbon (Ti-C:H) coatings with a wide range of Ti compositions[2]. Coating mechanical properties such as modulus and hardness have been measured by the technique of nanoindentation and correlated to Ti and hydrogen compositions[2,3].We have performed detailed microstructural examination of Ti-C:H coatings by transmission electron microscopy (TEM), Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy, and X-ray Absorption Near Edge Structure (XANES) spectroscopy.

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