Seibersdorf, Austria
Seibersdorf, Austria

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Montealegre-Melendez I.,University of Seville | Arevalo C.,University of Seville | Perez-Soriano E.M.,University of Seville | Neubauer E.,RHP Technology GmbH | And 2 more authors.
Materials | Year: 2017

In this work, a study of the influence of the starting materials and the processing time used to develop W/Cu alloys is carried out. Regarding powder metallurgy as a promising fabrication route, the difficulties in producing W/Cu alloys motivated us to investigate the influential factors on the final properties of the most industrially demanding alloys: 85-W/15-Cu, 80-W/20-Cu, and 75-W/25-Cu alloys. Two different tungsten powders with large variation among their particle size-fine (Wf) and coarse (Wc) powders-were used for the preparation of W/Cu alloys. Three weight ratios of fine and coarse (Wf:Wc) tungsten particles were analyzed. These powders were labelled as "tungsten bimodal powders". The powder blends were consolidated by rapid sinter pressing (RSP) at 900 °C and 150MPa, and were thus sintered and compacted simultaneously. The elemental powders and W/Cu alloys were studied by optical microscopy (OM) and scanning electron microscopy (SEM). Thermal conductivity, hardness, and densification were measured. Results showed that the synthesis of W/Cu using bimodal tungsten powders significantly affects the final alloy properties. The higher the tungsten content, the more noticeable the effect of the bimodal powder. The best bimodal W powder was the blend with 10 wt % of fine tungsten particles (10-Wf:90-Wc). These specimens present good values of densification and hardness, and higher values of thermal conductivity than other bimodal mixtures. © 2017 by the authors.

Moravcik I.,Brno University of Technology | Cizek J.,Brno University of Technology | Zapletal J.,Brno University of Technology | Kovacova Z.,RHP Technology GmbH | And 6 more authors.
Materials and Design | Year: 2017

The present work is focused on synthesis and mechanical properties evaluation of non-equiatomic Ni1,5Co1,5CrFeTi0,5, ductile single phase high entropy alloy (HEA) with excellent mechanical properties (bend strength Rmb = 2593 MPa, tensile strength Rm = 1384 MPa, tensile elongation to fracture of 4.01%, and elastic modulus of 216 GPa) surpassing those of traditional as-cast HEA. For the alloy production, a combination of mechanical alloying (MA) process in a planetary ball mill and spark plasma sintering (SPS) for powder densification was utilized. The tensile properties of a bulk material produced by a combination of MA + SPS are characterized for the first time. The feedstock powder and corresponding bulk material microstructure, elemental and phase composition, and mechanical properties were investigated by scanning (SEM) and transmission (TEM) electron microscopy, energy-dispersive X-ray spectroscopy (EDX), electron backscatter diffraction (EBSD), X-ray diffraction (XRD), as well as impulse excitation of vibration, Vickers microhardness and tensile and bend strength tests, respectively. The structure of the samples consisted of single-phase FCC high entropy solid solution of extremely fine-twinned grains and oxide inclusions inherited from the original powder feedstock. Dimple-like morphology corresponding to ductile fracture mode has been observed on the fracture surfaces, with crack initiation sites on the inclusions phases. © 2017 Elsevier Ltd

Montealegre-Melendez I.,University of Seville | Neubauer E.,RHP Technology GmbH | Arevalo C.,University of Seville | Rovira A.,University of Seville | Kitzmantel M.,RHP Technology GmbH
Key Engineering Materials | Year: 2016

Nowadays, the demands for materials with high strength based on a titanium matrix are increasing. The manufacturing of titanium composites through low cost and near-net-shape techniques is a challenge for the industry. There are different processing routes to meet these requirements of the market. As it is well known fast powder metallurgical densification techniques could satisfy these needs. In the present work, several titanium metal matrix composites (TiMMCs) have been fabricated by using a fast hot consolidation technique, namely direct hot pressing (dHP) in order to reduce the manufacturing time. Through a pressure assisted sintering with direct heating of a pressing die the consolidated composites can be formed directly from powders in a short period of time (15 min). The matrix materials were selected from two titanium grade 1 powders and as reinforcement materials boron carbide and boron amorphous particles were employed. Varying the reinforcement's content in addition to their particle size, their influence on the composites behaviour was expected. Furthermore in this research work, the mechanical and microstructural characterisation of the specimens was carried out in order to identify the best combination of process parameters, material reinforcement and matrix powders. © 2016 Trans Tech Publications, Switzerland.

Arevalo C.,University of Seville | Kitzmantel M.,RHP Technology GmbH | Neubauer E.,RHP Technology GmbH | Montealegre-Melendez I.,University of Seville
Key Engineering Materials | Year: 2016

Titanium and its alloys have evolved faster than any structural material in the history of metallurgy. The increasing employment of titanium in many different applications is mainly due to its light weight, high strength and structural efficiency. The titanium metal matrix composites (Ti-MMCs) have helped to achieve these objectives. The aim of this work is the development and study of Ti-MMCs manufactured via hot pressing at 900 °C reinforced by sub-micron and micron boron carbide (B4C), amorphous boron and sub-micron and micron titanium diboride (TiB2) particles in order to improve its mechanical properties. Full dense composites were obtained with this consolidation technique. The influence of the different reinforcements has been analyzed. Moreover, the strengthening effect of sub-micron reinforcements is compared to the effect of the material with the same chemical composition in a micro-scaled phase. Comparison has been established studying the microstructure (grain size and density) and mechanical properties through tensile and hardness tests. © 2016 Trans Tech Publications, Switzerland.

Agency: European Commission | Branch: FP7 | Program: CP-TP | Phase: FoF.NMP.2013-11 | Award Amount: 5.41M | Year: 2013

Volume production at industrial scale of miniaturised multi-material 3D (polymer-polymer, metal-polymer, metal-metal, polymer-ceramics,...) still face important challenges to be affordable by SMEs. Challenges not only in terms of precision manufacturing (precision engineering <0.01%) but also in the adequate interaction between the different constituent materials. Besides multi-material micro-system manufacturing processes still show to be time and cost consuming mainly from assembling activities and back en processes (35-60% of the total manufacturing costs come only from the assembling), so further research efforts in alternative and more integrated manufacturing concepts(over-moulding of micro-components and in-mould assembly technology would avoid the assembly step) are needed. To answer those problems the development of high-throughput and cost-efficient process chains based on micro injection should consider the following aspects: Improved volume production, not only from the standpoint of the necessary accuracy and performance of the process, but also regarding the interaction/bonding of the different materials which make up the produced parts and the possibility of selective functionality of their surfaces. The integration of the different processes including the feeding and handling systems for automatic operation in order to eliminate human intervention and manufacturing costs. Analyse the most suitable process control, online verification and back-end processes taking into account the features of the multi-material replicated parts represented by five demonstrators. The aim is to reduce manufacturing costs up to 40%. Thus, the HINMICO project final outcome will enable to produce high quality multi-material micro-components through more integrated, efficient and cheaper process chains.

Agency: European Commission | Branch: H2020 | Program: IA | Phase: WASTE-1-2014 | Award Amount: 9.28M | Year: 2015

The main vision of CABRISS project is to develop a circular economy mainly for the photovoltaic, but also for electronic and glass industry. It will consist in the implementation of: (i) recycling technologies to recover In, Ag and Si for the sustainable PV technology and other applications; (ii) a solar cell processing roadmap, which will use Si waste for the high throughput, cost-effective manufacturing of hybrid Si based solar cells and will demonstrate the possibility for the re-usability and recyclability at the end of life of key PV materials. The developed Si solar cells will have the specificity to have a low environmental impact by the implementation of low carbon footprint technologies and as a consequence, the technology will present a low energy payback (about 1 year). The originality of the project relates to the cross-sectorial approach associating together different sectors like the Powder Metallurgy (fabrication of Si powder based low cost substrate), the PV industry (innovative PV Cells) and the industry of recycling (hydrometallurgy and pyrometallurgy) with a common aim : make use of recycled waste materials (Si, In and Ag). CABRISS focuses mainly on a photovoltaic production value chain, thus demonstrating the cross-sectorial industrial symbiosis with closed-loop processes.

Agency: European Commission | Branch: FP7 | Program: CP-TP | Phase: NMP.2012.4.0-1 | Award Amount: 3.71M | Year: 2013

The demand for aesthetically integrated photovoltaic materials is increasing steadily in many industries. A growing number of designers, architects and industrial manufacturers across the world share a common interest in using Photovoltaics (PV) as a decentralized and sustainable source of energy in their product designs. Developing markets such as sustainable housing, temporary building structures, outdoor activities, electro-mobility and mobile computing will drive the demand for decentralized, attractive energy solutions. For solar powered products are customisable shapes, sizes, colours, transparencies or specific electrical properties required, which have a decisive influence on the acceptance on the market. Therefore a new breed of solar technologies is necessary. To achieve this goal new flexible production processes and materials need to be developed. A novel manufacturing process will enable the adjustment of all properties of a thin-film module on-the-fly and facilitate the production of customized photovoltaic modules with the desired voltage, size and shape. Combined with the material characteristics given by the underlying thin-film solar cell technology a new-breed of design-led, sustainable and decentralised energy solutions can be realized. Furthermore the designer or architect who wants to incorporate solar electricity into his work needs a service environment to be assisted in the creative process. Tools should support the designer in conceiving, planning and producing the solar design products. This project will address the above mentioned challenges by exploring and developing new materials, manufacturing and business processes in PV powered product design and architecture.

Kitzmantel M.,Vienna University of Technology | Neubauer E.,RHP Technology GmbH
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2015

This paper talks about high performance heat sinks and heat spreaders made by hybrid structures based on metaldiamond composites. Thermal conductivities can be tuned between 450 and 650 W/mK while maintaining customizable thermal expansion of 6-10 ppm/K (@30°C). Using different hybrid structures in combination with the metal-diamond core significant changes in thermal properties can be identified. Applications targeted are LED, disc laser and laser diode heatsinks with these high performance inserts without the need of CTE matched submounts. © 2015 SPIE.

Kovacova Z.,Slovak University of Technology in Bratislava | Baca L.,Slovak University of Technology in Bratislava | Baca L.,Aerospace and Advanced Composites GmbH | Neubauer E.,RHP Technology GmbH | Kitzmantel M.,RHP Technology GmbH
Journal of the European Ceramic Society | Year: 2015

The influence of sintering temperature, silicon carbide particle size (50-60nm, 0.9μm and 44μm) and yttrium oxide addition on oxidation behaviour of ZrB2-SiC ceramics was investigated up to 1650°C in static atmosphere. Weight changes were measured and the thickness of formed oxide layer was evaluated by the light and scanning electron microscopy. Results show enhanced oxidation resistance of ZrB2-SiC composites sintered at 1750°C in spite of their lower density (∼93.2%) due to the grain growth cessation resulting in the refinement of microstructure. Similarly the oxidation resistance was also enhanced by refinement of microstructure due the submicron or nano-sized starting SiC powders. The addition of Y2O3 caused desired stabilization of cubic ZrO2 phase; nevertheless the oxidation resistance of Y2O3 doped samples was inferior in comparison to the basic material at oxidation temperatures exceeding 1500°C. © 2015 Elsevier Ltd.

Agency: European Commission | Branch: H2020 | Program: SME-2 | Phase: Space-SME-2014-2 | Award Amount: 950.00K | Year: 2015

The main goal of this project is the development of an industrial plug & play system for additive layer manufacturing which is based on a blown powder process using Plasma Transferred Arc (PTA) Technology. The developed 4M System will offer: a) Simple equipment concept based on well established PTA technology for hard facing coatings b) Possibility to realize Multi-Material concepts c) Suitability of the technology to be used for a wide range of raw materials d) High deposition/building rates e) Possibility to realize large size components (up to 1,5 m x 1,5 m in the first version) Within the project the system will be developed to be used for wo different materials (Al and Ti-alloys) and to demonstrate one multi-material concept. The developed process will be used to realize three different demonstrators (case studies) and to perform testing of the manufactured prototypes under space relevant testing conditions.

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