Now showing 1 - 10 of 99
  • Publication
    Open Access
    Integrated Design Methodology for Advanced Functional Materials
    (2022) ; ; ; ;
    Pistidda, Claudio
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    Le, Thi Thu
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    Höche, Daniel
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    Deng, Min
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    Störmer, Michael
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    Krishnamurthy, Gnanavel Vaidhyanathan
  • Publication
    Open Access
    Computerized Refurbishment
    (2022) ; ; ; ; ; ; ;
    Huang, Chunjie
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    ; ; ;
    Rashikbhai Gabani, Dhruvit
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    Gibmeier, Jens
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    Pundt, Astrid
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    Werner, Tiago
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    Hilgenberg, Kai
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    Madia, Marco
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    Böllinghaus, Thomas
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    Holzgaßner, Leonhard
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    Richter, Peter
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    Clausing, Nils
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    Loitz, Henry
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    Keuter, Philipp
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    Baben, Moritz to
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    Steierl, Markus
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    Schimbäck, David Erich
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    Rösler, Thorsten
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    Debuch, Holger
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    Gartner, Thomas
  • Publication
    Open Access
    Towards Imaging-based Digital Design of Complex Functional Composites
    (2022) ; ; ; ;
    Pistidda, Claudio
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    Passing, Maximilian
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    Krywka, Christina
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    Moosman, Julian P.
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    Greving, Imke
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    Flenner, Silja
  • Publication
    Metadata only
    Knowledge-based Optimization of Cold Spray for Aircraft Component Repair
    In recent years, cold spraying (CS) has emerged as a promising technology for repair applications, particularly for oxidation-sensitive materials. In order to obtain an optimum repair result that fulfills the highest requirements regarding material properties, simple geometric shape restoration is not sufficient. Any additive manufacturing process results in particular features in microstructure, possible defects and respective – potentially even anisotropic – mechanical properties. To systematically tailor these microstructures and properties to the specific component and geometry requires complex routines. This work proposes the design of a knowledge-based cold spray repair system that facilitates a complete individual repair procedure for aircraft components. This system includes the elements of (i) reverse engineering to analyze, classify and generate digital data of the damaged component, (ii) pre-processing to obtain the ideal conditions for the CS process, (iii) toolpath planning to optimize robotics for the CS process, (iv) on-line monitoring to ensure process quality, (v) post-processing and (vi) performance testing of the material properties to meet the challenging requirements of the aerospace industry. By using an industrial robot and computer-aided planning of the trajectories, components are to be repaired under cold spray and geometrical conditions for ideal material deposition. The goal is to obtain repaired components that fulfill the required property profile equally well as respective new parts.
  • Publication
    Metadata only
    Size Effects of Brittle Particles in Aerosol Deposition - Molecular Dynamics Simulation
    (Springer, 2021-03-05) ; ;
    Assadi, Hamid
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    Höche, Daniel
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    © 2021, The Author(s). Up to now, the role of particle sizes on the impact behavior of ceramic particles in aerosol deposition not yet fully understood. Hence, with the aim to supply a more general understanding, modeling series of low strain rate compression and high-speed impact were performed by molecular dynamics on single-crystalline particles in sizes of 10-300 nm that are tuned to match mechanical properties of TiO2-anatase. The modeling results reveal that particles with original diameter of 25-75 nm exhibit three different impact behaviors that could be distinguished as (i) rebounding, (ii) bonding and (iii) fragmentation, depending on their initial impact velocity. In contrast, particles larger than 75 nm do not exhibit the bonding behavior. Detailed stress and strain field distributions reveal that combination of “localized inelastic deformation” along the slip systems and “shear localization” cause bonding of the small and large particles to the substrate. The analyses of associated temperature rise by the inelastic deformation revealed that heat diffusion at these small scales depend on size. Whereas small particles could reach a rather homogeneous temperature distribution, the evolved heat in the larger ones keeps rather localized to areas of highest deformation and may support deformation and the formation of dense layers in aerosol deposition.
  • Publication
    Metadata only
    冷喷涂技术及其系统的研究现状与展望
    (2021)
    Huang, Chunjie
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    Yin, Shuo
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    Li, Wenya
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    Guo, Xueping
    Cold spray (CS) technology has shown many advantages over the traditional thermal spray methods, such as lower deposition temperature, higher deposition efficiency and lower coating porosity. The inherent deficiencies such as the oxidation, decomposition, phase transformation and grain growth in the nano structured materials associated with fusion of materials can be thus avoided, which allow the deposition of oxidation sensitive materials, thermal sensitive materials and phase transformation sensitive materials. It is worth noting that as the development of cold spray systems it is used as one solid state rapid manufacturing method to realize the industrial applications of metal additive manufacturing and repairing the damaged aerospace component and parts. Due to the fact that cold spray has been increasingly attracted more and more attention from domestic researchers and industries, a detailed summary and discussion on the advancement of cold spray technology and its system based on the literature survey and a long-term tracking of domestic and foreign CS systems were presented. Firstly, the main components for a conventional cold spray system, the sprayed materials and the microstructures-properties of the corresponding deposits were briefly described. Then, the systems and applications of the traditional cold spray technologies, such as high pressure cold spray, low pressure cold spray and vacuum cold spray were discussed. In addition, the novel cold spray technologies developed based on the spray gun design or spray nozzle design (such as the inner diameter cold spray, the pulsed gas dynamic spray, the shock tunnel produced cold spray and the radial supersonic spray), and the hybrid processes of other techniques assisting cold spray (such as, the laser assisted cold spray, the electrostatic force assisted cold spray, the magnetic assisted cold spray and the friction stir processing assisted cold spray additive manufacturing) were analyzed. Finally, the existed key problems of cold spray technologies and its system were pointed out, and the prospect of its material research and industrial application was given.
  • Publication
    Open Access
    Kaltgasspritzen für die Leistungselektronik: Werkstoffkombinationen und geometrische Randbedingungen
    (Universitätsbibliothek der HSU / UniBwH, 2021)
    Ernst, Kerstin-Raffaela
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    Helmut-Schmidt-Universität / Universität der Bundeswehr Hamburg
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  • Publication
    Metadata only
    A new strategy for strengthening additively manufactured cold spray deposits through in-process densification
    (2020-12)
    Fan, Ningsong
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    Cizek, Jan
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    Huang, Chunjie
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    Xie, Xinliang
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    Chlup, Zdenek
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    Jenkins, Richard
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    Lupoi, Rocco
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    Yin, Shuo
    In this study, a novel strategy for strengthening additively manufactured cold spray deposits is proposed, based on a rather under-explored niche of the processing parameters space. We have shown that a combination of two factors (a wide particle size distribution of the feedstock powder and low processing parameters) triggered a successful implementation of this strategy. At such conditions, a significant proportion of the particles (particularly those with a large size) fail to deposit and rebound after their impact instead, initiating the in-process densification effect: by accepting a small price increase trade-off (the wide range powders are inexpensive), the rebounds result in a severe accumulative plastic deformation of the deposited particles and further reduction in porosity. These, in turn, lead to mechanical properties comparable to those produced under high processing parameters (i.e., using N2 gas at high temperatures or using expensive and unsustainable He as the propulsive gas). As a welcome benefit, the detrimental thermal effects encountered in cold spraying using high-temperature processing gas (such as oxidation, nitridation and phase changes) can be effectively minimized using the new low parameters strategy. Overall, the aim of this study is to propose a new manufacturing strategy to fabricate high-performance cold sprayed deposits without the use of expensive and unsustainable He gas.
  • Publication
    Metadata only
    Influence of MAX-Phase Deformability on Coating Formation by Cold Spraying
    (Springer, 2020-11-08)
    Busato, Marco
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    ; ;
    Bruera, Alessia
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    Bolelli, Giovanni
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    Lusvarghi, Luca
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