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Effects of TiO <sub/>2</sub> doping on microstructure and properties of directed laser deposition alumina/aluminum titanate composites
摘要： Al2O3-based composite ceramics have excellent high temperature performance and are ideal materials for preparing hot end components. However, poor fracture toughness and thermal shock resistance limit its applications. Based on the excellent low thermal expansion characteristics and thermal shock resistance of Al2TiO5 ceramic, different composition ratios of Al2O3/Al2TiO5 composite ceramics were prepared by directed laser deposition (DLD) technology. Effects of TiO2 doping amount on microstructure and properties of the composite ceramics were investigated. Results show that α-Al2O3 phase is discretely distributed in the continuous aluminum titanate matrix when TiO2 doping amount between 2 and 30 mol%. With the increase of TiO2 doping amount, content of Al2O3 gradually decreases and its morphology changes from cellular to dendritic. When TiO2 doping amount reaches 43.9 mol%, the microstructure transforms into fine Al2TiO5/Al6Ti2O13 eutectic structure. Property test results show that Al2O3/Al2TiO5 composite ceramics have good comprehensive mechanical properties when TiO2 doping amount between 2 and 6 mol%.
关键词： Al2O3/Al2TiO5,microstructure,Additive manufacturing,properties,composite ceramics
更新于2025-11-21 11:03:13
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Spectroscopic monitoring of laser blown powder directed energy deposition of Alloy 718
摘要： Experimental explorations of a spectrometer system used for in-process monitoring of the laser blown powder directed energy deposition of Alloy 718 is presented. Additive manufacturing of metals using this laser process experiences repeated heating and cooling cycles which will influence the final microstructure and chemical composition at every given point in the built. The spectrometer system disclosed, under certain process conditions, spectral lines that indicate vaporisation of chromium. Post process scanning electron microscope energy dispersive spectroscopy analysis of the deposited beads confirmed a reduction of chromium. Since the chromium concentration in Alloy 718 is correlated to corrosion resistance, this result encourages to further investigations including corrosion tests.
关键词： additive manufacturing,laser blown powder directed energy deposition,spectroscopic system,in-process monitoring
更新于2025-11-21 11:01:37
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Rapid Alloy Development of Extremely High-Alloyed Metals Using Powder Blends in Laser Powder Bed Fusion
摘要： The design of new alloys by and for metal additive manufacturing (AM) is an emerging field of research. Currently, pre-alloyed powders are used in metal AM, which are expensive and inflexible in terms of varying chemical composition. The present study describes the adaption of rapid alloy development in laser powder bed fusion (LPBF) by using elemental powder blends. This enables an agile and resource-efficient approach to designing and screening new alloys through fast generation of alloys with varying chemical compositions. This method was evaluated on the new and chemically complex materials group of multi-principal element alloys (MPEAs), also known as high-entropy alloys (HEAs). MPEAs constitute ideal candidates for the introduced methodology due to the large space for possible alloys. First, process parameters for LPBF with powder blends containing at least five different elemental powders were developed. Secondly, the influence of processing parameters and the resulting energy density input on the homogeneity of the manufactured parts were investigated. Microstructural characterization was carried out by optical microscopy, electron backscatter diffraction (EBSD), and energy-dispersive X-ray spectroscopy (EDS), while mechanical properties were evaluated using tensile testing. Finally, the applicability of powder blends in LPBF was demonstrated through the manufacture of geometrically complex lattice structures with energy absorption functionality.
关键词： multi-principal element alloys,high-entropy alloys,additive manufacturing,rapid alloy development,powder blends,laser powder bed fusion
更新于2025-11-21 11:01:37
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[IEEE 2018 13th International Congress Molded Interconnect Devices (MID) - Wu?rzburg (2018.9.25-2018.9.26)] 2018 13th International Congress Molded Interconnect Devices (MID) - Generation of 3D Functional Structures for High- Frequency Applications by Printing Technologies
摘要： Mechatronic Integrated Devices (MID) offer a high level of functional integration, miniaturization and allow a reduction of utilized components. Due to these benefits, the MID technology is constantly pushing forward into new application fields, e.g. for internet of things products. Most smart devices are equipped with sensors and have wireless capabilities to send and receive data. As the market requires faster transmission rates and higher frequencies, microwave technology is gaining more and more significance. One promising technology in order to enable highly integrated products is printed electronics. In this work, the suitability of a novel aerosol-based printing system is evaluated by generating microstrip lines. The created structures are characterized geometrically with a laser scan microscope and electrically with a network analyzer.
关键词： Microwave Technology,Additive Manufacturing,Printed Electronics
更新于2025-09-23 15:23:52
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Laser welding of electron beam melted Ti-6Al-4V to wrought Ti-6Al-4V: Effect of welding angle on microstructure and mechanical properties
摘要： Electron beam melting (EBM) is an established powder-bed additive manufacturing process for small-to-medium-sized components of Ti-6Al-4V. For further employing EBM on fabricating large-scale components, an effort has been made by joining EBM-built Ti-6Al-4V plates to wrought counterparts using laser welding, and the welding angles between EBM build direction and weld bead have been chosen as 0°, 30° and 45°. The influence of the welding angles on the microstructure, microhardness of base metals, fusion zone, and heat-affected zones, as well as the macro tensile test have been characterized. The microhardness of each zone is determined by the local microstructure, and the macro tensile properties largely depend on the EBM base metal due to the internal defects generated during the EBM process. The effect of welding angles on tensile strengths is not significant, while the elongation drops from 9.4% to 5.8% as the welding angle increases from 0° to 45°. The mechanism of stress during uniaxial tension on EBM base metal is discussed based on the stress state of columnar grains and the internal defects.
关键词： Defects,Microstructure,Mechanical properties,Additive manufacturing,Welding
更新于2025-09-23 15:23:52
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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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[IEEE 2018 International Conference on Information and Communication Technology Robotics (ICT-ROBOT) - Busan (2018.9.6-2018.9.8)] 2018 International Conference on Information and Communication Technology Robotics (ICT-ROBOT) - Design of Air Cooling Housing for Image Sensors Using Additive Manufacturing Technology
摘要： Machine vision is widely used in industry for monitoring and inspection. In additive manufacturing technology (AM), it is especially important in that it can cover an entire 2-dimensional printed surface area instantly. Additionally, AM technologies can also be used to make a mechanical part for a machine vision system such as mount or illumination devices on a 3D printer. For the industrial 3D printer, the camera mount requires to have temperature control capabilities for the vision system. This research aims to develop a method to build a mount with cooling capability with AM technology. This paper introduces a 3D printed camera cooling housing and proposes a temperature feed-back control method based on the image sensor itself without adding a thermal sensor to increase the user friendliness and simplicity. In the demonstration, a camera cooling housing that was developed enabled a camera module to operate at 200°C in an industrial Fortus 400 (Stratasys, MN).
关键词： camera cooling system,3d printed heat exchanger,additive manufacturing,vision based thermal control
更新于2025-09-23 15:22:29
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Chemical imaging of buried interfaces in organic-inorganic devices using FIB-ToF-SIMS
摘要： Organic-inorganic hybrid materials enable the design and fabrication of new materials with enhanced properties. The interface between the organic and inorganic materials is often critical to the device’s performance and therefore chemical characterization is of significant interest. Since the interfaces are often buried, milling by focused ion beams (FIB) to expose the interface is becoming increasingly popular. Chemical imaging can subsequently be obtained using secondary ion mass spectrometry. However, the FIB milling process damages the organic material. In this study, we make an organic-inorganic test structure to develop a detailed understanding of the processes involved in FIB milling and SIMS imaging. We provide an analysis methodology that involves a “clean-up” process using sputtering with an argon gas cluster ion source to remove the FIB induced damage. The methodology is evaluated for two additive manufactured devices, an encapsulated strain sensor containing silver tracks embedded in a polymeric material and a copper track on a flexible polymeric substrate created using a novel nanoparticle sintering technique.
关键词： FIB,additive manufacturing,hybrid interfaces,ToF-SIMS,polymer,Argon cluster,milling
更新于2025-09-23 15:22:29
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Design Guidelines for printable Magnetic Shielding Films for NFC Tags on
摘要： The performance of RFID tags deteriorates when mounted on metallic objects. This is due to the induced eddy current effect on the metal which produces a magnetic field that opposes the reader/ tag field. Suitable electromagnetic screening is needed to mitigate this issue e.g. ferromagnetic films shielding the tag from the metal. This paper explores some design guidelines for ferrite films properties for additive manufacturing methods. Simulated and measured results for different ferromagnetic films and their influence on the performance of the NFC tags are investigated.
关键词： NFC,additive manufacturing,ferromagnetic films,RFID
更新于2025-09-23 15:22:29
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Application of Aerosol Jet 3D Printing with Conductive and Non-Conductive Inks for Manufacturing mm-Wave Circuits
摘要： In this paper, an application of Aerosol Jet 3D printing with conductive and non-conductive inks for the realization of mm-wave circuits well above 30 GHz is presented and investigated. The Optomec 5X aerosol jet 3D printing system is used together with polyimide and silver inks to fully-additive manufacture various microstrip circuits. A section of microstrip transmission line with a transition to a via-less conductor backed coplanar waveguide was designed together with a T-junction and a branch-line coupler. These circuits were designed to operate within the Ka and V frequency bands. The measured thickness of the polyimide dielectric substrate is 20.7 ± 1.35 μm while the silver traces are 2.6 ± 1.35 μm. A section of the transmission line with the developed transitions was measured up to the W-band, exhibiting a total loss of 0.65 dB/mm at 100 GHz. The T-junction power divider yielded a total loss at its center frequency of 34 GHz of 0.55 dB. The 3-dB branch line coupler yielded a loss at its center frequency at 42 GHz of 1.1 dB. The experimental results demonstrate the application of this approach for fast and high-resolution mm-wave circuit fabrication.
关键词： circuit fabrication,additive manufacturing,mm-wave circuits,aerosol jet printing,3D printing
更新于2025-09-23 15:22:29