PLD-Preparation of carbon based multilayered coatingsR Bertram1, T Lampke2 and S Weißmantel11 Laserinstitut der Hochschule Mittweida2 Institut für Werkstoffwissenschaft und Werkstofftechnik der Technischen Universität Chemnitz. Results obtained in the analysis of single layer and multilayered carbon stacks produced by PLD at low temperature will be presented. The mechanical properties of carbon single layers deposited at various laser pulse fluences, like hardness and elasticity, were determined by means of nano indentation measurements. It will be shown that a wide variety of mechanical properties can easily be adjusted by adapting the process parameters.In addition, it will be demonstrated that the architecture of various pure carbon films strongly affects the coatings toughness. Scratch test measurements identified, therefore, that the cohesive break down of such layer systems can be hindered by refining the stack periodicity. This is along with no significant losses in hardness or elasticity if the stack architecture is suitable, as determined in nano indentation analyses. Furthermore, the resistance of different coating materials against abrasive wear were determined and compared. It was found that the carbon layer stacks again showed an outstanding performance.In summary, the produced coating systems combine a very good adhesion on several metal and hard metal substrates, very high hardness and elasticity accompanied with low abrasive wear and high crack and spalling resistivity.Production of tungsten-fibre reinforced tungsten composite by a novel continuous chemical vapour deposition processH Gietl1,*, J Riesch1, J W Coenen2, T Höschen1 and R Neu11 Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching, Germany2 Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung – Plasmaphysik, 52425 Jülich, Germany* e-mail: hanns.gietl@ipp.mpg.de. For the use in a fusion reactor tungsten has unique properties such as low sputter yield, high melting point and low activation. The brittleness below the ductile-to-brittle transition temperature and the embrittlement during operation are the main drawbacks for the use of pure tungsten. Tungsten fibre-reinforced tungsten composites overcome this problem by utilizing extrinsic mechanisms to improve the toughness. The next step in the material development is the production of larger components and testing under cyclic high heat flux loading. A dense matrix produced with a reliable production routine is one of the major issues for the production of such components. In this contribution we present a novel continuous process of chemical vapour deposition. It was achieved by designing and testing a set up For Rotary Enhanced Deposition (FRED) in the already existing W InfiLtration MAchine (WILMA), fabricating first samples. These samples were examined by microstructural analysis and compared to material produced by standard techniques. It is shown that this advanced set up in combination with tungsten fabrics allows the productions of tungsten-fibre reinforced tungsten composite in a faster and more defined way.Additively manufactured isotropic and defect tolerant material by EBM processing – A new alloy design approachJ Günther1,*, F Brenne1, M Droste2, M Wendler3, O Volkova3, H Biermann2 and T Niendorf11 Universität Kassel, Institut für Werkstofftechnik, Mönchebergstr. 3, 34125 Kassel, Deutschland2 TU Freiberg, Institut für Werkstofftechnik, Gustav-Zeuner Str. 5, 09599 Freiberg, Deutschland3 TU Freiberg, Institut für Eisen- und Stahltechnologie, Leipziger Str. 34, 09599 Freiberg, Deutschland* e-mail: Guenther@uni-kassel.de. Electron-beam melting (EBM) is an additive manufacturing (AM) technology allowing for the production of complex shaped components and efficient synthetization of advanced materials. Therefore, it recently gained high academic and industrial interest. However, the powder-bed based processes still face major challenges, e.g. evolution of strong textures and corresponding anisotropy imposed by epitaxial grain growth upon layer-wise consolidation of the initial powder. Furthermore, in most AM alloys process-induced defects detrimentally influence static and cyclic material properties. In the current study these issues are addressed by a new alloy designed for meeting the requirements set by current AM technologies. Firstly, the metastable austenitic steel in focus shows a distinct solidification mode and due to the presence of multiple solid state transformations induced by process-inherent intrinsic heat-treatment an equiaxed fine grained microstructure develops. Moreover, the alloy shows deformation induced phase transformation making it less susceptible to process-induced inhomogeneities. By controlling the process-parameters and the evaporation of volatile elements the deformation mechanisms and mechanical properties can be tailored for certain loading scenarios. For characterization X-ray diffraction, scanning electron microscopy and tensile testing have been employed. The presented alloy design could pave the way for a significant broadening of possible applications of powder-bed based AM components.Capability of 3D plasma metal deposition for additive manufacturing of multi-material componentsK Höfer*, A Hälsig and P MayrChair of Welding Engineering, Chemnitz University of Technology, Reichenhainer Straße 70, 09126 Chemnitz* e-mail: kevin.hoefer@mb.tu-chemnitz.de. Within this work, the 3D plasma-metal deposition (3DPMD), based on a plasma powder deposition process is introduced as arc-based additive manufacturing technology. Various powders can be fed into a plasma arc and allow realising a layer-by-layer build-up of metallic or composite structures. 3DPMD has certain advantages compared to the established powder bed or wire based additive manufacturing processes. For example, up to four different powders can be mixed individually within one layer. This allows a targeted adaption of local properties in terms of microstructure, mechanical properties, wear resistance, corrosion resistance, etc. to the targeted load type for the component and the anticipated service conditions. The study aims to demonstrate the suitability of 3DPMD for the production of multi material components in layer-by-layer design for steels, titanium and metal matrix composites. Demonstrators of various metallic materials and metal-matrix-composites have been generated. Geometrical features, microstructure, homogeneity and mechanical properties of the different structures are discussed with a focus on process-structure-property relationships. In summary, 3DPMD offers the possibility to produce various multi-material structures. Using automated routines, it is possible to generate metallic or composite structures directly from CAD data using welding robots. Microstructures and properties are directly related to the process parameters and therefore knowledge about process-structure-property relationships allows manufacturing of tailored multi-material components.Highly sensitive thin film strain sensors for integration in thermoplastic-based hybrid laminatesC Karapepas1, *, D Nestler2, D Wett1 and G Wagner11 Technical University of Chemnitz, Chair of Composites and Material Compounds, Chemnitz, Germany2 Technical University of Chemnitz, Chair of Lightweight Structures and Polymer Technology, Chemnitz, Germany* e-mail: christos.karapepas@mb.tu-chemnitz.de. Lightweight components comprised of fibre-reinforced plastics have become more important for many different industrial applications in recent years. However, to take full advantage of this relatively new class of materials systems, Structural Health Monitoring of these materials is a necessity. The solution concept aims to integrate nickel-carbon nanocomposite layers by (DC) magnetron sputtering onto polyimide substrates to use as highly sensitive and temperature-compensated strain sensors in hybrid laminates. A suitable polyimide carrier substrate had already been determined which had satisfied the required layer deposition properties and could be processed by the hot-pressing process. A mosaic target was also developed for the physical vapor deposition system. The generated Ni-C sensor layers were characterized in terms of their coating rate in the PVD process, composition, structure and their temperature coefficient of electrical resistance. To determine the k-factor, meandering strain gauges have been produced by means of a mask and characterized using tensile testing module. To check the temperature stability of the Ni-C layers with respect to the hot pressing process, they have been thermally deposited and a temperature-dependent Raman and x-ray diffraction analysis have also been carried out for this purpose. In addition, the change in the TCR value has been determined.Laser hardening of high-alloy steelP Landgraf1, T Grund1, E Haack2 and T Lampke11 Institute of Materials Science and Engineering, Chemnitz University of Technology Chair of Materials and Surface Engineering Group2 LHW GmbH. Laser hardening enable to heat the surface layer of the component and therefore to adjust the microstructure targeted and locally and thus the properties. The advantages of the process are short treatment times, a very good automation and easy integration in production lines as well as a high adaptability and flexibility. Target values of laser hardening are a requested hardness and the penetration depth of the laser track. The high heating rate and the short austenitization period, which is variable depending on the feed rate of the laser, makes the prediction of the laser treatment results difficult and requires an adaptation of the heat treatment parameters compared to conventionally heat-treated components. In high-alloy carbon-rich steels, such as the X153CrMoV12, different contents of carbon, chromium and other alloying elements are dissolved in the austenitic matrix during the laser treatment, depending on the austenitizing temperature. This complicates the process design and control in addition. During the investigations, the temperature and the feed rate of the laser and the surface condition (grounded and blasted) were varied. The laser tracks were analyzed by metallography and X-ray diffraction (XRD). Furthermore, the hardness profiles of the laser tracks were determined. The results show the potential influence of the different process parameters and surface conditions on the laser track in terms of hardness and penetration depths.Significance and characterization of complex formation for the galvanic deposition of cobaltM Müller*, I Scharf and T LampkeInstitute of Materials Science and Engineering, Chemnitz University of Technology, 09125 Chemnitz, Germany* e-mail: mueller.markus@mb.tu-chemnitz.de. Almost every galvanic electrolyte contains complexing agents as additives. They have the task to lowering the free metal ion concentration and to prevent the precipitation of metalhydroxides. However, it is not possible to make an electrodeposition out of every metal complex. As a reason for this phenomenon, the dissociation rate of the metal complex was evaluated. The paper shows a methodical selection of the complexing agent for the electrodeposition of cobalt, based on thermodynamic and kinetic parameters. Thus, complexing agents from the substance group amino acids, carboxylic acids and inorganic compounds can be specifically characterized for their suitability. For each system of cobalt-complexing agent the necessary pH range and the excess of complexing agent to stabilize the electrolyte, can be calculated. This leads to an estimation of the applicability of a complexing agent for the galvanic process.Influence of Nano-Roughness on the Electrical Resistance of SiC micro FibersS Palaniyappan, T Ega and G WagnerInstitute of Materials Science and Engineering, Chemnitz University of Technology, Chemnitz, Germany. In most of the fiber reinforced composites, the surface roughness of the reinforcing fiber has got quite a great impact on the amount of radial clamping stress being delivered between the fiber and the matrix. On the other hand, the change in average surface nano-roughness (Sa) of the fibers, which is caused by means of desizing, also influences their electrical resistance (Ra). In applications of composite materials, that demand the use of an embedded single fiber as a piezo-resistive sensor, the effect of this nano-roughness modification on their electrical resistance needs to be characterized. In this contribution, Silicon Carbide (SiC) ceramic fibers were desized using low temperature annealing in atmospheric air and the Sa values were determined using Laser Scanning Microscopy (LSM). The Ra measurements were carried out using 2-wire method connected to a Keithley source meter. The Sa and Ra of the desized fibers are found to be directly proportional to the time periods for the respective temperatures. However, while comparing between the two temperatures, the decrease in Sa at the higher temperature actually lead to an increase in Ra of the fibers. This phenomenon of investigating the effect of nano-roughness on the electrical resistance of SiC fibers paves the way to decide on the desired desizing temperature and time period for applications like fiber sensors, fiber coatings etc.Neural Network for Predicting Plasma Nitriding ResultsJ Pribbenow1, P Landgraf1, M Mejauschek2, T Grund1 and T Lampke11 Institute of Materials Science and Engineering, Chemnitz University of Technology, 09125 Chemnitz, Germany2 Zentrum für Tribologische Schichten, Fraunhofer-Institut für Schicht- und Oberflächentechnik, Bienroder Weg 54 E, 38108 Braunschweig, DE. An artificial neural network, particularly a backpropagation neural network (BPNN), has been developed to investigate the hardening behavior of different steel types according to various process parameters. Therefore, steels with different chemical compositions were plasma nitrated to study the hardness profile and surface hardness. The experimental data were used to train the neural network. For an optimal training, the weight distribution, hidden neurons and gradients of neuron activation functions were varied. This should facilitate a simulation of the hardness profile for types of steel with deviant chemical composition and nitriding parameters.Influence of Spray Angle and Spray Time on the Geometry of WC-Co HVOF FootprintsW Tillmann, C Schaak* and O KhalilTU Dortmund University, Institute of Materials Engineering, Germany* e-mail: christopher.schaak@udo.edu. Currently, thermal spray guns mounted on and moved by robots are state of the art. Nevertheless, both the kinematics and dynamics of the robot are solely taken into account in the field of thermal spraying, although they both strongly influence the resulting coating properties. Manual teaching as well as automatic offline path planning are initial and simple steps to solve some of the movement problems with the robot to achieve better coating results. A second step is the optimization of a generated path with regard to the characteristics of the thermal spray process. For this purpose, a coating development simulation, which depends on the robot movement, is one approach to optimize the paths. Footprints / spray patterns can be used as input values for the coating development simulation. A footprint shows the mass flow of spray material at different lateral positions on the surface. However, the footprint geometry itself is influenced by different spray parameters. These deviations can lead to inaccuracies in the final simulation. Hence, the deviations of the footprint geometries for different spray angles and spray times were investigated and quantified. The obtained information will be used to improve the coating development simulation and to achieve a higher precision for the path optimization.Thermal fatigue testing of sand casted AlSi10MgB Zillmann* and S BucherCR/APM2, Robert Bosch GmbH, 71272 Renningen, Germany* e-mail: benjamin.zillmann@de.bosch.com. Sand casted aluminum is extensively used in heat exchangers for gas-fired applications. Consequently, a temperature gradient occurs over the wall thickness and causes transient thermal stresses. The thermal stresses are mainly influenced by the design, boundary conditions and the power of the heat exchanger. This thermal fatigue problem is well known and needs to be considered for the validation of new designs or if other changes in the system take place. So far, system tests are carried out to validate the required lifetime which is time consuming and therefore expensive due to the high cycles times for heating and cooling. The validation time can be drastically reduced by replacing the system tests to mechanical design element tests. Therefore, the transferability from thermal fatigue to the isothermal mechanical fatigue behavior needs to be considered. A new strategy for thermal fatigue testing will be introduced and finally compared to the isothermal mechanical fatigue behavior.