Artykuły w czasopismach: „Micro-metallic components”

1

Zhang, Wenwu, i Y. Lawrence Yao. "Micro Scale Laser Shock Processing of Metallic Components". Journal of Manufacturing Science and Engineering 124, nr 2 (29.04.2002): 369–78. http://dx.doi.org/10.1115/1.1445149.

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Laser shock processing of copper using focused laser beam size about ten microns is investigated for its feasibility and capability to impart desirable residual stress distributions into the target material in order to improve the fatigue life of the material. Shock pressure and strain/stress are properly modeled to reflect the micro scale involved, and the high strain rate and ultrahigh pressure involved. Numerical solutions of the model are experimentally validated in terms of the geometry of the shock-generated plastic deformation on target material surfaces as well as the average in-depth strains under various conditions. The residual stress distributions can be further influenced by shocking at different locations with certain spacing. The potential of applying the technique to micro components, such as micro gears fabricated using MEMS is demonstrated. The investigation also lays groundwork for possible combination of the micro scale laser shock processing with laser micromachining processes to offset the undesirable residual stress often induced by such machining processes.

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SUZUKI, Hirofumi, Daisuke MUKOHATA, Takeshi KAWANO, Yuji YAMAMOTO, Keiichi NAKAMOTO, Toshiroh SHIBASAKA i Toshimichi MORIWAKI. "3606 Precision Molding of Micro Metallic Glass Components". Proceedings of the JSME annual meeting 2007.4 (2007): 277–78. http://dx.doi.org/10.1299/jsmemecjo.2007.4.0_277.

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Kim, J. S., Kyle Jiang, C. Lucien Falticeanu, G. J. Davies i I. T. H. Chang. "Making Alumina Microcomponents From Al Powder". Materials Science Forum 534-536 (styczeń 2007): 1041–44. http://dx.doi.org/10.4028/www.scientific.net/msf.534-536.1041.

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Alumina microcomponents have distinguishing advantages over Si counterparts. However, the shrinkage of alumina, as high as 20%, makes it difficult to produce precision components that require a high tolerance. A new fabrication process is presented to greatly reduce the shrinkage. The process consists of forming an Al powdered component through sintering and transforming the Al powdered component into an alumina part. In this way, the shrinkage occurring in sintering the Al powder component will be compensated by the expansion occurred when Al transforms into alumina. The process involves producing micro-moulds, preparing metallic paste, filling the micro-moulds with the metallic paste, demoulding, sintering the green Al patterns and finally oxidising the sintered Al-based components to achieve alumina components. The process was proven successful. Characterization of the sintered alumina microcomponents has been undertaken, including SEM image analysis, density and scale measurements.

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Liu, Jian, Hany Hassanin, Zhenyu Ni, Yi Yang, Gang Yang i Kyle Jiang. "Production of high-precision micro metallic components by electroforming process". Materials and Manufacturing Processes 32, nr 12 (18.08.2016): 1325–30. http://dx.doi.org/10.1080/10426914.2016.1221092.

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Essa, Khamis, Francesco Modica, Mohamed Imbaby, Mahmoud Ahmed El-Sayed, Amr ElShaer, Kyle Jiang i Hany Hassanin. "Manufacturing of metallic micro-components using hybrid soft lithography and micro-electrical discharge machining". International Journal of Advanced Manufacturing Technology 91, nr 1-4 (22.11.2016): 445–52. http://dx.doi.org/10.1007/s00170-016-9655-4.

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Zhang, Xiang, Jiang Ma, Ran Bai, Qian Li, Bing Li Sun i Chang Yu Shen. "Polymer Micro Hot Embossing with Bulk Metallic Glass Mold Insert". Advanced Materials Research 510 (kwiecień 2012): 639–44. http://dx.doi.org/10.4028/www.scientific.net/amr.510.639.

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Polymer microstructures are used more and more in many fields. Hot embossing is one of molding processing to achieve micro polymer components. In this paper, bulk metallic glass was selected as mold material to fabricate mold insert of micro hot embossing. Traditional UV-lithography and ICP-etching were used to achieve micro features on silicon wafer. And then, micro features were transferred from silicon wafer to bulk metallic glass mold insert above its glass transition temperature. Finally, applied bulk metallic glass mold insert to replicate polymer microstructure with hot embossing. Three commonly used thermoplastic polymers: high-density polyethylene (HDPE), polypropylene (PP) and polycarbonate (PC) were selected in this study. Experiments show that microstructures can have a good replication from bulk metallic glass mold insert to the thermoplastic polymer using hot embossing.

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Ray, Debajyoti, Asit Baran Puri i Nagahanumaiah. "Investigation on Cutting Forces and Surface Finish in Mechanical Micro Milling of Zr-Based Bulk Metallic Glass". Journal of Advanced Manufacturing Systems 18, nr 01 (13.02.2019): 113–32. http://dx.doi.org/10.1142/s0219686719500069.

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Precision micro-component fabrication demands suitable manufacturing processes that ensure making of parts with good form and finish. Mechanical micro milling represents a flexible and powerful process that exhibits enhanced capability to create micro features. Bulk metallic glass (BMG) represents a young class of amorphous alloy material with superior mechanical and physical properties and finds appreciable micro scale applications like biomedical devices and implants, micro parts for sport items and various other micro- components. In the present work, an attempt has been made to analyze the influence of the cutting parameters like spindle speed, feed per tooth and axial depth of cut on the machinability of BMG, in mechanical micro-milling process. The micro-milling process performances have been evaluated concerning to cutting forces and surface roughness generated, by making full slots on the workpiece with solid carbide end mill cutters. The paper presents micro-machining results for bulk metallic glass machined with commercial micro-milling tool at low cutting velocity regime. Response surface methodology (RSM) has been employed for process modeling and subsequent analysis to study the influence of the combination of cutting parameters on responses within the selected domain of cutting parameters. It has been found that the effect of axial depth of cut on the cutting force components is remarkably significant. Cutting force components increases with the increase in axial depth of cut and decreases with increase in spindle speed. At low feed rate, cutting force in the feed direction (Fx, i.e., cutting force along x-direction) increases with a decrease in feed rate. This increase of force could be due to the possible ploughing effect. A similar pattern of variation has been observed with cutting force component in cross-feed direction (Fy) also. It has been found that effect of feed per tooth on the roughness parameter Ra is remarkably significant. Surface roughness increases with feed per tooth. Axial depth of cut does not contribute much to the surface roughness. Surface roughness decrease with the increase of spindle speed.

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Lee, Hye Jin, Nak Kyu Lee i Hyoung Wook Lee. "A Study on the Micro Property Testing of Micro Embossing Patterned Metallic Thin Foil". Key Engineering Materials 345-346 (sierpień 2007): 335–38. http://dx.doi.org/10.4028/www.scientific.net/kem.345-346.335.

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In this paper, Experimental results on the measurement of mechanical properties of fine patterns in the MEMS structure are described. The mechanical properties of embossing patterns on metallic thin foil is measured using the nano indentation system, that is developed by Korea Institute of Industrial Technology(KITECH). These micro embossing patterns are fabricated using CIP(Cold Isostatic Press) process on micro metallic thin foils(Al-1100) that are made by rolling process. These embossing patterned metallic thin foils(Al-1100) are used in the reflecting plate of BLU(Back Light Unit) and electrical/mechanical MEMS components. If these mechanical properties of fine patterns are utilized in a design procedure, the optimal design can be achieved in aspects of reliability as well as economy.

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Sundriyal, Sanjay, Vipin i Ravinderjit Singh Walia. "Experimental Investigation of the Micro-hardness of EN-31 Die Steel in a Powder-Mixed Near-Dry Electric Discharge Machining Method". Strojniški vestnik – Journal of Mechanical Engineering 66, nr 3 (15.03.2020): 184–92. http://dx.doi.org/10.5545/sv-jme.2019.6474.

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The Powder-Mixed Near-Dry Electric Discharge Machining (PMND-EDM) methodology has proven to be efficient in terms of machining rate, surface morphology, and environmental friendliness, unlike traditional EDM. In this study, the presence of a conductive metallic powder (zinc) in the dielectric medium was responsible for changing the topography of the workpiece (EN-31) and resulted in a higher micro-hardness value of the machined component. In this research, an approach has been made to optimize the significant process parameters by using a Taguchi L9 orthogonal array (OA) to obtain machined components with higher values of micro-hardness, which was measured in terms of Vickers hardness HV. The selected process parameters were tool diameter, mist flow rate, metallic powder concentration, and dielectric mist pressure. By introducing foreign particles (metallic powder), the topography of the machined products has been improved, and the micro-hardness value was found to be enhanced. The confirmation experiment was performed for optimal process parameter settings, and the enhanced microhardness value was found to be 506.63 HV in the machined EN-31 die steel.

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Li, J.-B., K. Jiang i G. J. Davies. "Novel die-sinking micro-electro discharge machining process using microelectromechanical systems technology". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 220, nr 9 (1.09.2006): 1481–87. http://dx.doi.org/10.1243/09544062jmes323ft.

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A novel die-sinking micro-electro discharge machining (EDM) process is presented for volume fabrication of metallic microcomponents. In the process, a high-precision silicon electrode is fabricated using deep reactive ion etching (DRIE) process of microelectromechanical systems (MEMS) technology and then coated with a thin layer of copper to increase the conductivity. The metalized Si electrode is used in the EDM process to manufacture metallic microcomponents by imprinting the electrode onto a flat metallic surface. The two main advantages of this process are that it enables the fabrication of metallic microdevices and reduces manufacturing cost and time. The development of the new EDM process is described. A silicon component was produced using the Surface Technology Systems plasma etcher and the DRIE process. Such components can be manufactured with a precision in nanometres. The minimum feature of the component is 50 μm. In the experiments, the Si component was coated with copper and then used as the electrode on an EDM machine of 1 μm resolution. In the manufacturing process, 130 V and 0.2 A currents were used for a period of 5 min. The SEM images of the resulting device show clear etched areas, and the electric discharge wave chart indicates a good fabrication condition. The experimental results have been analysed and the new micro-EDM process is found to be able to fabricate 25 μm features.

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Vella, Pierre C., Stefan S. Dimov i Alexander Kolew. "Process chain for serial manufacture of polymer components with micro- and nano-scale features: Optimisation issues". Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 231, nr 11 (5.02.2016): 2000–2020. http://dx.doi.org/10.1177/0954405415619344.

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This article reports a follow-up research to investigate further the component technologies of a cost-effective manufacturing route designed to achieve function and length scale integration in products. The route employs a viable master-making process chain that integrates compatible and at the same time complementary, structuring and replication technologies to fabricate Zr-based bulk metallic glass inserts. To validate them, they are subsequently integrated into a micro-injection moulding machine, and polymer structures incorporating both micro- and nano-scale features are replicated. Especially, the masters and/or replicas after each processing step were analysed and the factors affecting its overall performance were identified. The research demonstrated that the master-making process chain can be a viable fabrication route for both fully amorphous and partially crystalline Zr-based bulk metallic glass inserts that incorporate different length scale features. The results also showed that relatively good fidelity of the different scale features can be achieved with the micro-injection moulding process, and thus, it can enable function and length scale integration in thermoplastic components.

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Imbaby, M., K. Jiang i I. Chang. "Net shape fabrication of stainless-steel micro machine components from metallic powder". Journal of Micromechanics and Microengineering 18, nr 11 (7.10.2008): 115018. http://dx.doi.org/10.1088/0960-1317/18/11/115018.

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Weimer, Daniel, Silke Huferath von Luepke, Andreas Tausendfreund, Ralf B. Bergmann, Gert Goch i Bernd Scholz-Reiter. "Dimensional In Situ Shape and Surface Inspection of Metallic Micro Components in Micro Bulk Manufacturing". Advanced Materials Research 1018 (wrzesień 2014): 493–500. http://dx.doi.org/10.4028/www.scientific.net/amr.1018.493.

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A rising trend to miniaturization and function integration requires new materials, tools, manufacturing setups and quality inspection strategies for mass production of micro mechanical systems (MMS). In most scenarios, quality inspection is carried out manually. An expert takes samples out of the manufacturing process and investigates them by means of tactile or optical measurement systems. This time consuming quality inspection process leads to low inspection rates, especially in bulk manufacturing processes, where manufacturing frequencies of 400 parts per minute are common. This contribution introduces an automated optical quality inspection method based on a digital holographic system, which acquires 2D texture and 3D shape information in one single measurement step. Based on 3D data, an automated point separation algorithm splits the measured object shape into elementary geometries and calculates form and position deviations compared to an object model. In the final step, a 2D surface inspection procedure based on multi-scale texture analysis detects surface defects with respect to the separated elementary geometries and fuses the result from the 3D shape and the 2D texture analysis to a final rejection decision. The capability of the proposed quality inspection method is demonstrated in a micro cold forming scenario, where a micro cup smaller than 1 mm in all geometric dimensions is the object under investigation.

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YAMASAKI, Tohru. "Developments of High Strength Ni-W Electrodeposited Alloys and Micro Metallic Machine Components". Journal of The Surface Finishing Society of Japan 73, nr 3 (1.03.2022): 135–41. http://dx.doi.org/10.4139/sfj.73.135.

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Piotter, Volker, Alexander Klein, Klaus Plewa, Markus Guttmann i Frank Winkler. "Development of stacked conductive templates for electroforming of multi-level metallic micro components". Microsystem Technologies 26, nr 5 (25.11.2019): 1585–90. http://dx.doi.org/10.1007/s00542-019-04699-3.

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Kimura, Yasuhiro, i Masumi Saka. "Fabrication of Multiple Al Micro-Materials by Electromigration Using a Comb Pattern and a Conductive Passivation Film". Advanced Materials Research 909 (marzec 2014): 36–40. http://dx.doi.org/10.4028/www.scientific.net/amr.909.36.

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Electromigration (EM) is the phenomenon of atomic diffusion in a metallic film with a high-density electron flow. Our group used EM to fabricate Al micro-materials. The EM technique can be used to fabricate micro-materials with a high aspect ratio, pure metal components, an arbitrary form, and a single-crystal structure. Recently, two micro-materials have been simultaneously fabricated using an array pattern consisting of parallel or series connections. However, multiple micro-materials have not been fabricated simultaneously thus far. In this study, a new comb sample pattern was used with a conductive passivation film to produce multiple Al micro-materials.

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Hartl, Christoph. "Review on Advances in Metal Micro-Tube Forming". Metals 9, nr 5 (10.05.2019): 542. http://dx.doi.org/10.3390/met9050542.

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Metallic tubular micro-components play an important role in a broad range of products, from industrial microsystem technology, such as medical engineering, electronics and optoelectronics, to sensor technology or microfluidics. The demand for such components is increasing, and forming processes can present a number of advantages for industrial manufacturing. These include, for example, a high productivity, enhanced shaping possibilities, applicability of a wide spectrum of materials and the possibility to produce parts with a high stiffness and strength. However, certain difficulties arise as a result of scaling down conventional tube forming processes to the microscale. These include not only the influence of the known size effects on material and friction behavior, but also constraints in the feasible miniaturization of forming tools. Extensive research work has been conducted over the past few years on micro-tube forming techniques, which deal with the development of novel and optimized processes, to counteract these restrictions. This paper reviews the relevant advances in micro-tube fabrication and shaping. A particular focus is enhancement in forming possibilities, accuracy and obtained component characteristics, presented in the reviewed research work. Furthermore, achievements in severe plastic deformation for micro-tube generation and in micro-tube testing methods are discussed.

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Rahman, M. Azizur, Mustafizur Rahman i A. Senthil Kumar. "Material perspective on the evolution of micro- and nano-scale cutting of metal alloys". Journal of Micromanufacturing 1, nr 2 (13.07.2018): 97–114. http://dx.doi.org/10.1177/2516598418782318.

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Microfabrication plays an active role in miniaturization of products and components in various emerging fields ranging from pharmaceuticals and bio-medical applications to electro-mechanical sensors and actuators to chemical microreactors and mechanical microturbines. Tool-based machining is one of the key technologies of microfabrication. The machining of materials on the micrometre and nanometre scales is fundamental for the fabrication of 3D micro components. However, there are limitations of scaling down the mechanical machining process from the macro- to micro- to nanoscales. Several factors that are not significant in conventional machining become significant in micro/nano-scale machining. This article identifies the important material-related issues on the evolution of micro cutting from conventional cutting process. The main focus is given to the state-of-the art micro/nano-cutting technologies of metal alloys with material perspective. Furthermore, a promising research of coupling the additive and subtractive manufacturing technologies has been highlighted to improve the surface quality of 3D-printed metallic parts.

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Wang, Yucheng, Qi Zhong, Risheng Hua, Lidong Cheng, Chunju Wang, Haidong He, Feng Chen i Zhenwu Ma. "Ultrasonic Vibration-Assisted Stamping of Serpentine Micro-Channel for Titanium Bipolar Plates Used in Proton-Exchange Membrane Fuel Cell". Materials 16, nr 9 (28.04.2023): 3461. http://dx.doi.org/10.3390/ma16093461.

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Metallic bipolar plates (BPPs) are key components in the proton-exchange membrane fuel cell (PEMFC), which can replace traditional fossil fuels as a kind of clean energy. However, these kinds of plates, characterized by micro-channels with a high ratio between depth and width, are difficult to fabricate with an ultra-thin metallic sheet. Then, ultrasonic-vibration-assisted stamping is performed considering the acoustic softening effect. Additionally, the influence of various vibration parameters on the forming quality is analyzed. The experimental results show that ultrasonic vibration can obviously increase the channel depth. Among the vibration parameters, the vibration power has the maximum influence on the depth, the vibration interval time is the second, and the vibration duration time is the last. In addition, the rolling direction will affect the channel depth. When the micro-channels are parallel to the rolling direction, the depth of a micro-channel is the largest. This means that the developed ultrasonic-vibration-assisted stamping process is helpful for improving the forming limitation of micro-channels used for the bipolar plates in PEMFC.

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Rajenthirakumar, D., R. Sridhar, R. Abenethiri i Dwarkesh Bagri. "Experimental Investigations of Material Behaviour in Forward Micro Extrusion". Applied Mechanics and Materials 813-814 (listopad 2015): 536–40. http://dx.doi.org/10.4028/www.scientific.net/amm.813-814.536.

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Micro manufacturing has received good attention globally in terms of its manufacturing methods and processes. One of the most popular micro manufacturing processes is micro forming. Although there were efforts made to realize micro extrusion for industrial application, the technology itself was seen as being insufficiently mature and unlike conventional methods, there is no in-depth knowledge. It has become essential to develop a proper understanding which in turn could be used to develop dedicated processes for the manufacturing of metallic micro components. In this work, an attempt has been made to realize this special application of metal forming. A novel experimental setup consisting of forward extrusion assembly and a loading set-up has been developed to obtain the force-displacement response. The effects of minaturization on micro components and the material behavior during forward extrusion are investigated. As per industrial requirement and application of micro part in micro manufacturing process, grain size is an important factor. In this context the effect of grain size is also studied in this work. The realization of such a productive forward extrusion assembly poses significant advantages when compared to the conventional manufacturing technologies in the production of micro parts.

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JIN, Peng, i Jung-Sik KIM. "Design and Fabrication of a Micro Reciprocating Engine". Combustion Engines 122, nr 3 (1.07.2005): 32–41. http://dx.doi.org/10.19206/ce-117398.

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This paper presents an ongoing project of developing a micro reciprocating internal combustion engine. The engine is designed on the basis of a two stroke piston engine, but heavy modifications have been made to suit the 2D MEMS fabrication. All the engine parts are located in two layers. Piston seals are not used and leakage is prevented by the introduction of microgrooves on the piston, tight tolerance control and an extended contact area between the piston and the cylinder. With the assistance of a film of lubrication oil, these measures prove effective in preventing leakage. A new approach has been developed to fabricate high temperature resistant engine components at low cost. The approach relies on the UltraThick SU-8 Process (UTSP) to make micromoulds; then ceramic and metallic engine components can be produced based on the moulds. The UTSP is a UV lithography process for producing up to 1000 ?m thick SU-8 layers and the quality of the fabrication results can be compared with those made by using X ray exposure process in the same thickness. A complete microengine has been fabricated in SU-8 using the UTSP for test drive. High quality ceramic and metallic components have been produced based on the SU-8 moulds, proving the new approach is feasible for building

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Yamamoto, Y., i Soshu Kirihara. "Development of WC-Co/SUS304 Functionally Graded Materials by Using Three Dimensional Micro Welding". Materials Science Forum 631-632 (październik 2009): 265–70. http://dx.doi.org/10.4028/www.scientific.net/msf.631-632.265.

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Three dimensional micro welding (3DMW) of a novel freeform fabrication process for metal or alloy components has been developed in our investigation group. A tungsten inert gas (TIG) welding machine is controlled by utilizing CAD/CAM processes. Various types of metal or alloy wires are fed automatically under a micro-arc torch to form tiny metallic beads. These micrometer order beads are joined continuously to build three dimensional structures. Near-net-shape components of metal or alloy compounds with high melting points can be fabricated automatically with minimized energy and resources. In this study, tungsten carbide-cobalt (WC-Co) and stainless steel (SUS304) micro beads of 1.0 mm in diameter were stacked alternately to fabricate cutting tools with graded structures by using the 3DMW. The microstructure and hardness were observed by scanning electron microscope (SEM), energy dispersive spectra (EDS) and Vickers hardness tester. The maximum hardness of micro bead was approximately 1300 HV and no crack or pore existed in the formed objects.

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Buzdugan, Dragoş, Cosmin Codrean, Viorel Aurel Şerban i Mircea Vodǎ. "Mechanical Behavior of Fe₆₀Co₁₄Ga₂P₁₀B₅Si₃Al₃C₃Bulk Metallic Glass". Solid State Phenomena 216 (sierpień 2014): 45–48. http://dx.doi.org/10.4028/www.scientific.net/ssp.216.45.

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Development of Fe-based bulk metallic glasses (BMG) with good mechanical and soft magnetic properties has become a major objective in the materials science field. Bulk metallic glasses present an interesting combination of properties. They exhibit very high strength (both in tension and compression), large elastic elongation limit, high hardness, excellent corrosion resistance, and good soft magnetic properties. These properties makes them suitable for many applications like high resistant control cables, pressure vessels, micro-components, pressure sensors, microgears for motors, magnetic cores for power supplies and hard fibers in composite materials. Multi-component Fe60Co14Ga2P10B5Si3Al3C3bulk metallic glass was synthesized in rod form with a diameter of 1 mm by copper mould casting technique using raw industrial materials. The obtained alloy was analyzed by X-ray diffraction (XRD), differential thermal analysis (DTA) and scanning electron microscopy (SEM) techniques, in order to determine the phase constituent, the thermal stability and the fracture surfaces of as-cast samples. The mechanical behaviour was investigated by microhardness and compression tests. The values recorded for hardness and fracture strength includes this alloy in the category of high resistant materials.

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Weimer, Daniel, Hendrik Thamer, Carolin Fellmann, Michael Lütjen, Klaus-Dieter Thoben i Bernd Scholz-Reiter. "Towards 100% In-situ 2D/3D Quality Inspection of Metallic Micro Components Using Plenoptic Cameras". Procedia CIRP 17 (2014): 847–52. http://dx.doi.org/10.1016/j.procir.2014.01.115.

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Li, C. Z., Z. T. Xu, L. F. Peng i X. M. Lai. "Investigation on thickness size effect on ductility of magnetron sputtered Niobium coatings on SS316L substrate for forming of precoated metallic bipolar plates". IOP Conference Series: Materials Science and Engineering 1270, nr 1 (1.12.2022): 012111. http://dx.doi.org/10.1088/1757-899x/1270/1/012111.

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Metallic bipolar plates (BPPs) are key components of the proton exchange membrane fuel cell (PEMFC). To lower the fabrication cost of metallic BPPs, precoated BPPs have attracted much attention due to the high efficiency of precoating-stamping process. However, precoatings on metallic substrate tend to crack during the forming process, leading to deterioration or even complete loss of corrosion resistance. Therefore, to avoid micro cracks of formed precoated BPPs, development of coatings with high ductility is necessary. In this study, Niobium coatings with different thicknesses on SS316L substrate are prepared with magnetron sputtering process, and uniaxial tensile tests are then conducted for the precoated specimens to evaluate their ductility. The microstructure and fracture behaviour of the Niobium precoatings are characterized by XRD, SEM, TEM, laser confocal microscope analysis. It is found that with the increase of coating thickness, the number of micro cracks at the same strain decreases significantly, and the strain for the first crack to appear also increases. Furthermore, a brittle-to-ductile transition of fracture mechanism is observed. The grain size of Niobium nanocrystalline coating increases with the thickness, which leads to the improvement of plasticity and failure strain. Therefore, the application of precoated metallic BPPs is further advanced.

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Kowalski, Piotr R., Monika Kasina i Marek Michalik. "Distribution of minor metallic elements within waste incineration bottom ashes defined by WDX/EDX spectrometry". Advances in Geosciences 45 (5.09.2018): 259–65. http://dx.doi.org/10.5194/adgeo-45-259-2018.

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Abstract. A number of metallic elements are inherited from waste during thermal treatment and concentrated in the incineration residues. Because the major part of the incineration residue mass are bottom ashes (BAs), their study is of great importance from the point of view of their environmental impact or resource potential. The general focus of this study was on the minor metallic elements present in BAs. They co-occurred with main phases and often determined the inherited potential of the material. The analysed residues were produced from municipal and industrial waste. The BAs were studied using spectroscopic methods of chemical microanalysis: energy dispersive X-ray spectrometry (EDX) and wavelength dispersive X-ray spectrometry (WDX). Both the main and minor metallic elements were concentrated in metallic components. They were typically present as separate grains and metallic inclusions (commonly in the glass matrix of the grains) ranging in size from several to hundreds of micrometres. Despite Fe-, Al- and Cu-rich occurrences, metallic elements rarely occurred in fragments composed of a single element. Their main forms of occurrence were alloy grains, admixtures in polymetallic occurrences and micro-inclusions in glassy matrix. The content of particular elements in those forms was investigated and described in greater detail. Even though two types of bottom ash were formed from different types of waste and differences in used technologies were present, the obtained materials contained metallic components having similar attributes. Elevated concentrations of not only Fe and Al, but also Ti, Cu and Zn, allow us to consider bottom ash as a promising material from the point of view of metallic elements' recovery (e.g. by the physical concentration of elements through gravity or magnetic methods).

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Yamada, Rui, Noriharu Yodoshi i Akira Kawasaki. "Novel Fabrication Process of Micro Components by Viscous Flowing of Iron Based Metallic Glassy Monodispersed Particles". Tetsu-to-Hagane 100, nr 8 (2014): 1006–13. http://dx.doi.org/10.2355/tetsutohagane.100.1006.

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Liu, Yong, Haoran Chen, Shenghai Wang, Kan Wang, Minghao Li i Tengfei Peng. "Micro Electrochemical Milling of Micro Metal Parts with Rotating Ultrasonic Electrode". Sensors 20, nr 22 (19.11.2020): 6617. http://dx.doi.org/10.3390/s20226617.

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With the rapid development of MEMS, the demand for metal microstructure is increasing. Micro electrochemical milling technology (MECM) is capable of manufacturing micro metallic devices or components based on the principle of electrochemical anode dissolution. To improve the capacity of MECM, this paper presents a compound method named ultrasonic vibration-assisted micro electrochemical milling technology (UA-MECM). Firstly, the simulation and mathematical model of UA-MECM process is established to explain the mechanism of ultrasonic vibration on micro electrochemical milling. Then, the effects of ultrasonic parameters, electrical parameters and feedrate on machining localization and surface quality are discussed considering sets of experiments. The surface roughness was effectively reduced from Ra 0.83 to Ra 0.26 µm with the addition of ultrasonic vibration. It turns out that ultrasonic vibration can obviously improve machining precision, efficiency and quality. Finally, two- and three-dimensional microstructures with good surface quality were successful fabricated. It shows that ultrasonic vibration-assisted electrochemical milling technology has excellent machining performance, which has potential and broad industrial application prospects.

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Zhang, H. D., L. Deng i X. Y. Wang. "Research on ultrasonic vibration assisted ploughing-extrusion process in forming μ-scale micro grooves". IOP Conference Series: Materials Science and Engineering 1270, nr 1 (1.12.2022): 012104. http://dx.doi.org/10.1088/1757-899x/1270/1/012104.

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The surface micro groove structure on metallic components has received extensive attention for its role in improving the heat transfer coefficient. Limited by the size effect, it is difficult to manufacture μ-scale micro groove structure with large depth-to-width ratio through conventional extrusion or rolling processes. A novel UV assisted ploughing-extrusion process was proposed to manufacture μ-scale micro grooves. A series of UV assisted compression tests were conducted to study the acoustic deformation behavior of α-Ti, and a modified Ludwik model were established., The influence of deformation parameters was investigated, and the optimized deformation parameters are the leading angle is 60°, the extruded angle is 40°, and the ultrasonic amplitude is 10.30 μm. The results indicate that the novel ultrasonic vibration assisted ploughing-extrusion is able to continuously form large-sized micro-grooves parts with high quality.

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Jamshidi, Reihaneh, Yuanfen Chen, Kathryn White, Nicole Moehring i Reza Montazami. "Mechanics of Interfacial Bonding in Dissimilar Soft Transient Materials and Electronics". MRS Advances 1, nr 36 (2016): 2501–11. http://dx.doi.org/10.1557/adv.2016.432.

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ABSTRACTSoft transient electronics of polymeric substrates and silver-ink electronics are studied for correlated mechanical-electrical properties. Experimental and predictive finite element analysis are used to understand, explain and predict delamination, cracking, buckling, and failure of printed conductive components of such systems. An active transient polymer system consisting of poly(vinyl alcohol) and sodium bicarbonate is introduced that results in byproducts (alkaline and bubbles) when undergoing transiency. These byproducts are facilitated to control and expedite transiency of the electronic components based on redispersion of metallic nano/micro materials. Complete mechanical and electrical characterization of such systems is reported.

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Wang, Xinwei, Jie Xu, Chunju Wang, Antonio J. Sánchez Egea, Jianwei Li, Chen Liu, Zhenlong Wang, Tiejun Zhang, Bin Guo i Jian Cao. "Bio-Inspired Functional Surface Fabricated by Electrically Assisted Micro-Embossing of AZ31 Magnesium Alloy". Materials 13, nr 2 (16.01.2020): 412. http://dx.doi.org/10.3390/ma13020412.

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Developing bio-inspired functional surfaces on engineering metals is of extreme importance, involving different industrial sectors, like automotive or aeronautics. In particular, micro-embossing is one of the efficient and large-scale processes for manufacturing bio-inspired textures on metallic surfaces. However, this process faces some problems, such as filling defects and die breakage due to size effect, which restrict this technology for some components. Electrically assisted micro-forming has demonstrated the ability of reducing size effects, improving formability and decreasing flow stress, making it a promising hybrid process to control the filling quality of micro-scale features. This research focuses on the use of different current densities to perform embossed micro-channels of 7 μm and sharklet patterns of 10 μm in textured bulk metallic glass dies. These dies are prepared by thermoplastic forming based on the compression of photolithographic silicon molds. The results show that large areas of bio-inspired textures could be fabricated on magnesium alloy when current densities higher than 6 A/mm2 (threshold) are used. The optimal surface quality scenario is obtained for a current density of 13 A/mm2. Additionally, filling depth and depth–width ratio nonlinearly increases when higher current densities are used, where the temperature is a key parameter to control, keeping it below the temperature of the glass transition to avoid melting or an early breakage of the die.

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Zhang, Lin, Abolfazl Zolfaghari, Wenchen Zhou, Yang Shu i Allen Y. Yi. "Flexible metallic mold based precision compression molding for replication of micro-optical components onto non-planar surfaces". Precision Engineering 76 (lipiec 2022): 149–59. http://dx.doi.org/10.1016/j.precisioneng.2022.03.015.

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Fu, M. W., J. L. Wang i A. M. Korsunsky. "A review of geometrical and microstructural size effects in micro-scale deformation processing of metallic alloy components". International Journal of Machine Tools and Manufacture 109 (październik 2016): 94–125. http://dx.doi.org/10.1016/j.ijmachtools.2016.07.006.

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Kraus, Martin, i Marion Merklein. "Investigation of Size Effects in Multi-Stage Cold Forming of Metallic Micro Parts from Sheet Metal". Micromachines 12, nr 12 (15.12.2021): 1561. http://dx.doi.org/10.3390/mi12121561.

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Product miniaturisation and functional integration are currently global trends to save weight, space, materials and costs. This leads to an increasing demand for metallic micro components. Thus, the development of appropriate production technologies is in the focus of current research activities. Due to its efficiency, accuracy and short cycle times, microforming at room temperature offers the potential to meet the steadily increasing demand. During microforming, size effects occur which negatively affect the part quality, process stability, tool life and handling. Within this contribution, a multi-stage bulk microforming process from sheet metal is investigated for the materials Cu-OFE and AA6014 with regard to the basic feasibility and the occurrence of size effects. The results reveal that the process chain is basically suitable to produce metallic micro parts with a high repeatability. Size effects are identified during the process. Since several studies postulate that size effects can be minimised by scaling down the metallic grain structure, the grain size of the aluminium material AA6014-W is scaled down to less than one micrometre by using an accumulative roll bonding process (ARB). Subsequently, the effects of the ultrafine grain (UFG) structure on the forming process are analysed. It could be shown that a strengthened material state increases the material utilization. Furthermore, too soft materials can cause damage on the part during ejection. The occurring size effects cannot be eliminated by reducing the grain size.

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Kumar, Vijay, Rajeev Verma, Vishal S. Sharma i Varun Sharma. "Recent progresses in super-hydrophobicity and micro-texturing for engineering applications". Surface Topography: Metrology and Properties 9, nr 4 (1.12.2021): 043003. http://dx.doi.org/10.1088/2051-672x/ac4321.

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Abstract Increasing interests have been prevalent lately among the research fraternity for the development of superhydrophobic surfaces (SHS) considering the favorable properties exuded by them. Recently, SHS have been employed effectively in diverse engineering applications like self-cleaning/anti-dust, anti-reflecting coatings, corrosion resistance, anti-biofouling, biomedical, oil-water separation, drag reduction, anti-icing, and cavitation erosion. Further, patterned topology by micro/nano surface texturing has been perceived lately as an engineering opportunity to enhance the surface performance and has opened various avenues for exploration. This work reports the recent research findings pertaining to the concept of superhydrophobicity and micro-texturing particularly in the context of their application for the impediment of the adversaries in metallic components. The comprehensive review on SHS and micro-texturing suggests that the integrated application of these surface modification techniques are proficient for mechanical interlocking of the deposited coatings.

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Fan, Guochao, Xiaolei Chen, Krishna Kumar Saxena, Jiangwen Liu i Zhongning Guo. "Jet Electrochemical Micromachining of Micro-Grooves with Conductive-Masked Porous Cathode". Micromachines 11, nr 6 (30.05.2020): 557. http://dx.doi.org/10.3390/mi11060557.

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Surface structures with micro-grooves have been reported to be an effective way for improving the performance of metallic components. Through-mask electrochemical micromachining (TMEMM) is a promising process for fabricating micro-grooves. Due to the isotropic nature of metal dissolution, the dissolution of a workpiece occurs both along the width and depth. Overcut is generated inevitably with increasing depth, which makes it difficult to enhance machining localization. In this paper, a method of electrochemical machining using a conductive masked porous cathode and jet electrolyte supply is proposed to generate micro-grooves with high machining localization. In this configuration, the conductive mask is directly attached to the workpiece, thereby replacing the traditional insulated mask. This helps in achieving a reduction in overcut and an improvement in machining localization. Moreover, a metallic nozzle is introduced to supply a jetted electrolyte in the machining region with enhanced mass transfer via a porous cathode. The simulation and experimental results indicate that as compared with an insulated mask, the use of a conductive mask weakens the electric field intensity on both sides of machining region, which is helpful to reduce overcut and enhance machining localization. The effect of electrolyte pressure is investigated for this process configuration, and it has been observed that high electrolyte pressure enhances the mass transfer and improves the machining quality. In addition, as the pulse duty cycle is decreased, the dimensional standard deviation and roughness of the fabricated micro-groove are improved. The results suggest the feasibility and reliability of the proposed method.

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Yang, Sam, Da Chao Gao, Tim Muster, Andrew Tulloh, Scott Furman, Sheridan Mayo i Adrian Trinchi. "Microstructure of a Paint Primer - a Data-Constrained Modeling Analysis". Materials Science Forum 654-656 (czerwiec 2010): 1686–89. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.1686.

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Metallic aerospace components are commonly painted with a primer to improve their corrosion resistance. The primer contains a polymer matrix with embedded corrosion inhibitor and filler particles. Its performance is determined by the microscopic distributions of the particles. Various techniques have been used to quantify such distributions, including X-ray micro-computed tomography (CT). However, its success is sometimes limited by factors such as different particles having similar X-ray CT absorption properties and their size being smaller than the resolution of micro-CT. In this paper, we have performed two X-ray CT measurements on a paint primer sample consisting of SrCrO4 corrosion inhibitor particles and UV-absorbing TiO2 filler particles. Fe and Ti targets were used as X-ray sources with different spectral distributions. The measured CT data sets were used as constraints for a data-constrained microstructure modeling (DCM) prediction of the sample’s microscopic structures. DCM model predictions were compared with experimental elemental surface maps and showed reasonable degree of agreement, suggesting X-ray micro-CT combined with DCM modeling would be a powerful technique for detailing the dynamics of chromate-inhibited primers and other multiphase systems where the components are sensitive to incident X-ray energy.

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OHMURA, W., Y. SUZUKI, H. IMASEKI, T. ISHIKAWA, H. ISO, T. YOSHIMURA i Y. TAKEMETSU. "PIXE ANALYSIS ON PREDOMINANT ELEMENTAL ACCUMULATION ON THE MANDIBLE OF VARIOUS TERMITES". International Journal of PIXE 17, nr 03n04 (styczeń 2007): 113–18. http://dx.doi.org/10.1142/s0129083507001162.

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Information concerning the metallic component of termite mandibles may provide a significant clue for solving the evolutionary theory of termite species. Micro-beam scanning PIXE analysis was used, which is a power tool for detecting elemental components, along with two-dimensional information about the elemental distribution in the analyzed area. The distribution of three specific elements ( Mn , Zn and Cl ) is the focus of this paper. Especially, Mn and Zn are known to be distinctive factors in taxonomic studies of termite mandibles. In this study, mandibles of 12 species from 5 families were analyzed. Mn was detected in all the termites, except for Mastotermes darwiniensis. On the other hand, only kalotermitid termites had Zn as a predominant metal in the cutting edges. The elemental analysis of these mandibles showed significant information to solve the uncertainty of the phylogenetic relation of termites.

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Zhang, Junzhong, Pingmei Ming, Xinmin Zhang, Ge Qin, Liang Yan, Xiaokang Zhao i Xingshuai Zheng. "Facile Fabrication of Highly Perforated Hollow Metallic Cylinder with Changeable Micro-Orifices by Electroforming-Extrusion Molding Hybrid Process". Micromachines 11, nr 1 (9.01.2020): 70. http://dx.doi.org/10.3390/mi11010070.

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A seamless thin-walled hollow metallic cylinder with array of micro-perforations is one of the key components for some products. Normally, these micro-perforations are formed by removing material from the given metallic hollow cylinder (pipe or tube) one by one or row by row. To efficiently and flexibly manufacture such a highly perforated hollow cylinder, this paper proposed a hybrid technique combining extrusion moulding process and electroforming process. In the hybrid technique, the extrusion moulding process was used to create polymer extrusion patterns on the outside surface of the given stainless steel (SS) pipe, and then the electroforming process was carried out using the SS pipe as the mandrel. The formation of the polymer extrusion patterns was simulated and extruding molding experiments were carried out to examine the feasibility of the various mandrels. Electroforming experiments were implemented to verify the achievement of the seamless perforated thin-walled hollow cylinder. It was found that five different types of polymer extrusion pattern were able to be obtained on the same extruding pipe just by adjusting some extruding conditions and parameters, and correspondingly four types of perforated hollow cylinder with different tapered orifices are produced after the electroforming process. The obtainable perforations are: perforation with double conic-orifices, perforation with hemispheric orifice and conic orifice, unidirectionally tapered perforation, and straight-walled perforation. The geometric profile of the extrusion patterns is highly dependent on the processing conditions and parameters. The proposed hybrid process represents a promising alternative process to fabricate seamless thin-walled perforated hollow metallic cylinder efficiently, flexibly, and with low cost.

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Zarbov, Martin, David Brandon, Leah Gal-Or i Nissim Cohen. "EPD of Metallic Silver Particles: Problems and Solutions". Key Engineering Materials 314 (lipiec 2006): 95–100. http://dx.doi.org/10.4028/www.scientific.net/kem.314.95.

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Cerel has devoted the past several years to the development of prototype microcomponents for the electronics industry based on EPD processing. The present contribution summarizes some problems Cerel has experienced in the integration of EPD for metallic silver particles into a viable production process. In particular, the parameters that need to be controlled due to the metallic nature of the silver particles have been analyzed. Selection of a metallic silver powder suitable for EPD is the key factor. An appropriate particle size and shape, as well as a controlled size distribution, significantly improves the green density of the deposit. Metallic silver particles in a suspension tend to aggregate, especially when exposed to an electric field. This leads to premature sedimentation, as well as low green densities for the electrophoretic deposit. The following factors were found to contribute significantly to preventing premature sedimentation: • The replacement of pure silver by palladium-coated silver particles. • Dispersion preparation in a high viscosity medium of low dielectric constant. • The presence of steric, electrosteric and ceramic oxide additives in the siver powder dispersion. Finally, control of the solids loading and particle size distribution in the suspension, and the geometrical design of the EPD cell, including the counter-electrodes, were also shown to be important for the successful electrophoretic deposition of silver particles in the commercial production of micro-components by EPD.

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Fejdyś, Marzena, Karolina Olszewska, Sylwia Kaczmarczyk i Grzegorz Owczarek. "Coatings manufactured using magnetron sputtering technology to protect against infrared radiation for use in firefighter helmets". Polish Journal of Chemical Technology 18, nr 3 (1.09.2016): 50–58. http://dx.doi.org/10.1515/pjct-2016-0048.

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Abstract The aim of this study was to test the usefulness of magnetron sputtering technology to produce coatings on selected elements of a firefighter’s helmet to protect against infrared radiation (PN-EN 171 standard). The scope of research includes testing the deposition produced via magnetron sputtering of metallic and ceramic coatings on plastics, which are used to manufacture the components comprising the personal protection equipment used by firefighters. The UV-VIS, NIR used to research the permeation coefficients and reflections for light and infrared light and the emission spectrometry with ICP-AES used for the quantitative analysis of elements in metallic and ceramic coatings. Microstructural and micro-analytical testing of the coatings were performed using scanning electron microscopy (SEM). Measurements of the chemical compositions were conducted using energy-dispersive X-ray spectroscopy (EDS). The hardnesss of the coatings were tested using a indentation method, and the coating thicknesses were tested using a ellipsometry method.

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Pahlevani, Farshid, Koichi Anzai i E. Niyama. "Quick Semi-Solid Slurry Making Method Using Metallic Cup". Solid State Phenomena 141-143 (lipiec 2008): 463–68. http://dx.doi.org/10.4028/www.scientific.net/ssp.141-143.463.

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The needs for high-strength and light weight structural materials have increased in automotive and aerospace structure applications. The semi-solid processed light alloys inherently offer the opportunity to produce high integrity components for these requirements. Various processing methods exist for applying agitation to a molten metal during solidification to obtain metal slurries suitable for semi-solid metal processing. In this paper, a new technique (Cup-Cast method) to achieve semi-solid metal structure using agitation and direct spherical growth during solidification is reported. Cup-Cast method is the most quick and simple semi-solid processing route which semi-solid slurry would be prepared just by pouring molten metal into a metallic cup. In this study Cup-Cast method was introduced and effect of process parameters on micro-structural characterization of slurry prepared by this method was investigated.

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Pasupuleti Kirti Teja, Parvati Ramaswamy i Narayana Murthy S.V.S. "Thermal Shock and Oxidation Stability Tests to Grade Plasma Sprayed Functionally Gradient Thermal Barrier Coatings". Frontiers in Advanced Materials Research 1, nr 1 (30.05.2019): 1–11. http://dx.doi.org/10.34256/famr1911.

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Functionally graded layers in thermal barrier coatings reduce the stress gradient between the overlaid ceramic coatings and the underlying metallic component. Introduced to alleviate early onset of spallation of the coating due to thermal expansion mismatch, this facilitates improvement in the life of the component. Conventional thermal barrier coatings typically comprise of duplex layers of plasma sprayed 8% yttria stabilized zirconia (ceramic) coatings on bond coated (NiCrAlY) components/substrates (Inconel 718 for example). This work highlights the superiority of plasma sprayed coatings synthesized from blends of the intermetallic bond coat and ceramic plasma spray powders on Inconel 718 substrates in three-layer configuration over the duplex layered configuration. Assessed through (a) thermal shock cyclic tests (at 1200oC and 1400oC) in laboratory scale basic burner rig test facility and (b) oxidation stability test in high temperature furnace (at 800oC and 1000oC) the functionally graded coatings of certain configurations exhibited more than double the life of the conventional 8% yttria stabilized zirconia duplex (double layer) coatings. Micro- and crystal structure analysis support the findings and results are detailed and discussed.

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Hofmann, Christian, Maulik Satwara, Martin Kroll, Sushant Panhale, Patrick Rochala, Maik Wiemer, Karla Hiller i Harald Kuhn. "Localized Induction Heating of Cu-Sn Layers for Rapid Solid-Liquid Interdiffusion Bonding Based on Miniaturized Coils". Micromachines 13, nr 8 (12.08.2022): 1307. http://dx.doi.org/10.3390/mi13081307.

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Considering the demand for low temperature bonding in 3D integration and packaging of microelectronic or micromechanical components, this paper presents the development and application of an innovative inductive heating system using micro coils for rapid Cu-Sn solid-liquid interdiffusion (SLID) bonding at chip-level. The design and optimization of the micro coil as well as the analysis of the heating process were carried out by means of finite element method (FEM). The micro coil is a composite material of an aluminum nitride (AlN) carrier substrate and embedded metallic coil conductors. The conductive coil geometry is generated by electroplating of 500 µm thick copper into the AlN carrier. By using the aforementioned micro coil for inductive Cu-Sn SLID bonding, a complete transformation into the thermodynamic stable ε-phase Cu3Sn with an average shear strength of 45.1 N/mm2 could be achieved in 130 s by applying a bond pressure of 3 MPa. In comparison to conventional bonding methods using conduction-based global heating, the presented inductive bonding approach is characterized by combining very high heating rates of about 180 K/s as well as localized heating and efficient cooling of the bond structures. In future, the technology will open new opportunities in the field of wafer-level bonding.

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Mahdavi, Hamidreza, Konstantinos Poulios i Christian F. Niordson. "Determination of optimal residual stress profiles for improved rolling contact fatigue resistance". MATEC Web of Conferences 300 (2019): 06002. http://dx.doi.org/10.1051/matecconf/201930006002.

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A theoretical framework is developed for the evaluation of favorable residual stress profiles, suppressing fatigue damage initiation in rolling contact fatigue. Non-metallic inclusions at the microstructure of bearings are one of the most important reasons for fatigue damage initiation since they act as stress risers. In order to evaluate the stress state around such inclusions at the micro-scale, macroscopic stress histories are determined by Hertzian contact theory at different depths below the raceway for a typical roller bearing. These stress distributions are then used as far-field stresses for a micro-scale model accounting for single inclusions of different geometries and orientations. Eshelby’s method is used to relate far-field and local stresses in the vicinity of inclusions. The von Mises stress criterion is then used as a conservative estimator of crack initiation due to micro-scale plasticity. The effect of compressive residual stresses added to the axial and circumferential normal stress components at different depths is analyzed. The von Mises stress field around different inclusions at different depths is investigated in order to determine the most critical case in terms of micro-scale plastic deformation. Finally, an optimization process is carried out in order to determine the residual stresses that minimize the maximum observed von Mises stress as a function of depth.

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Sadowski, Tomasz, i Przemysław Golewski. "Heat Transfer in Composites Subjected to Temperature Variations". Solid State Phenomena 216 (sierpień 2014): 140–45. http://dx.doi.org/10.4028/www.scientific.net/ssp.216.140.

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The heat transfer problem in the 2-phase composite material containing metallic and elastic phases, subjected to quick temperature variations, is the aim of theoretical analysis. The full description of the composite behaviour starts from the formulation of governing equations at 2-scale levels: micro-and macro-, passes through specification of the internal structure of the composite and finishes by numerical solution of the heat transfer problem through the considered material sample. The most important in the analysis are thermo-mechanical properties of the composite components creating the material. The big difference of the both phases properties (mismatch) can create additional difficulty in the exact thermal description of the composite. It is necessary also to specify by scanning electron microscopy (SEM) observations a real material internal structure, which includes: grain shapes and matrix, to create of the proper size of the Representative Volume Element (RVE) for numerical calculations.In the numerical example we analyse cermet, i.e. the composite build up of metallic matrix (cobalt) and tungsten carbide elastic grains, which exhibits high brittleness. Heat transfer across this very complex material causes heat flux concentrations in the metallic phase and further stress concentrations. These concentrations act as sources of damage initiators at the binder/carbide grains interfaces. The obtained results lead to the conclusion that the spatial distribution and content of the metallic phase first of all influence the heat transfer across the 2-phase composites.

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Huang, You Min, Yi Syun Wu i Shung Ping Wang. "The Fabrication of a Micro-Channel for Metallic Bipolar Plates Using a Rubber Pad Forming Process". Key Engineering Materials 626 (sierpień 2014): 16–26. http://dx.doi.org/10.4028/www.scientific.net/kem.626.16.

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A bipolar plate is one the most crucial and costliest of the various components of a proton exchange membrane fuel cell (PEMFC). It is important to reduce the cost of bipolar plate, not only in terms of material, but also in terms of the manufacturing process, to allow the commercialization of PEMFC’s. The performance of PEMFC’s is also of importance. Metallic bipolar plates have been the subject of much attention recently, because of their low material cost, formability and excellent thermal and mechanical prosperities. Therefore, this study uses a rubber pad forming process for stainless 316L steel to fabricate a bipolar plate with serpentine channels. A computational fluid dynamics (CFD) analysis is performed, in order to determine the influence of channel geometries, such as channel width, channel height and rib width, on the flow distribution of the reactant. Using the CFD results, finite element analysis models are then constructed and the formability of the micro-flow channel is studied. Finality, experiments are conducted to determine the channel height and thickness distribution of the bipolar plate. The numerical results are verified by the experimental results.

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Reimche, W., Friedrich Wilhelm Bach, Rainer Duhm, G. Mroz i M. Bernard. "Setting of Gradient Material Properties and Quality Control of High Tension 3D-Weld Joints". Advanced Materials Research 22 (sierpień 2007): 113–25. http://dx.doi.org/10.4028/www.scientific.net/amr.22.113.

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Modern metallic materials used in high loading structures are increasingly being placed under stringent standards with regard to the mechanical strength and deformation properties of their individual parts as well as with regard to the loading capacity of their junctions. In order to determine the strain profile of the individual structural components, the mentioned topics will be taken from the SFB 675 “High tensile, locally manipulated structural components and structures” from the subproject C4 “Setting of gradient material properties and qualification of high-tension 3D-NVEB weld joints”. To this end, the strengthened individual structural components will be heated with an electron beam at defined locations. This is done in order to observe the load related local micro-structure changes and consequently the targeted, structured local changes in the strength and deformation properties of the material. A delay in the crack growth will also be sought after. Additionally, components with specifically designed tensile strength will be welded to high quality structures. At this the young but efficient non vacuum electron beam welding method will be preferably developed, qualified and used because of its good welding properties regarding to an improved beam positioning, process control and weld joint defect detection.

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Giannuzzi, Lucille A., Richard Young i Pete Carleson. "Using a Focused Ion Beam (FIB) System to Extract TEM-Ready Samples from Complex Metallic and Ceramic Structures". Microscopy Today 7, nr 2 (marzec 1999): 12–15. http://dx.doi.org/10.1017/s1551929500063860.

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AbstractDriven by the analytical needs of microelectronics, magnetic media and micro-fabrication industries, focused ion beam (FIB) systems are now capable of milling and manipulating samples for the analysis of microstructure features having dimensions of 180 nm or less, A technique for locating and extracting site specific specimens for examination by transmission electron microscopy (TEM) has been developed. An identified feature can be located and precisely milled with an FIB system from two sides to prepare an ultrathin sample, and then extracted from the region with a glass rod micromanipulator onto a grid for TEM analysis. This specimen preparation method has been applied to semiconductor failure analysis and to the study of metallic and ceramic microsiructures with irregular topographies and complex mufti-layered components.

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Qayyum, Muhammad Saqib. "Production of a Permanent Mold Gravity Die Cast A356.0 Aluminum Alloy Motorbike Shock Absorber through Casting Simulation". Key Engineering Materials 659 (sierpień 2015): 676–80. http://dx.doi.org/10.4028/www.scientific.net/kem.659.676.

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Motorbike shock absorbers of gravity die cast aluminum A356.0 alloy were being imported in the as-cast condition and later on machined at local foundries and workshops by sub-vendors to achieve the required dimensions and on many occasions a nearly complete solid block was cast and machined to achieve the desired shape but this process not only lowered the metallic yield but also the high machining costs and time required made it very uneconomical. Motorbike shock absorbers are critical vehicle components which are always under load and must never fail suddenly without warning therefore they need to be free of defects like shrinkage and micro-porosity. The thin wall thickness of 6mm and troublesome nature of cores required makes this component quite difficult for the conventional metal caster. The current research paper deals with the methoding, die designing, modeling and simulation, optimization and finally casting of these components following the data produced by the former. Initially a single piece per mold was suggested but later on considering the economics of the project two pieces i.e. left and right were recommended to be cast from a single sprue in each die with a vertically parted permanent die mold. For the methoding calculations the Thermal modulus has been used instead of the conventional casting modulus and for gating the naturally pressurized system is incorporated. Throughout the simulation process a significant number of iterations were made to achieve the final design which ensured a laminar flow of liquid aluminum below the critical velocity limit; the actual die casting results yielded good comparison with the simulation studies showing shrinkage cavity away from the risers and micro-porosity only in ingates.

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