Browsing by Keyword "info:eu-repo/grantAgreement/EC/FP7/608729/EU/Energy Efficient Manufacturing Process of Engineering Materials/EFFIPRO"
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Item Development of electric resistance sintering process for the fabrication of hard metals: Processing, microstructure and mechanical properties: Processing, microstructure and mechanical properties(2017-08-01) Lagos, M.A.; Agote, Iñigo; Schubert, T.; Weissgaerber, T.; Gallardo, J.M.; Montes, J.M.; Prakash, L.; Andreouli, C.; Oikonomou, V.; Lopez, D.; Calero, J.A.; EXTREMATThis work presents the development of the Electrical Resistance Sintering (ERS) process for the fabrication of hard metals. The compositions of the materials produced were WC with 6 and 10 wt% of Co. In addition to the specific characteristics of the technology, the characterization of the produced parts is presented and compared to materials obtained by conventional processes. The parts produced by ERS present densities comparable to the ones obtained by conventional methods. The microstructural comparison shows a considerable grain size reduction in the ERS materials which consequently brings a hardness increase. ERS materials show similar fracture toughness to conventional ones. The very fast sintering allows performing the process without any protective atmosphere, therefore making this process very attractive for the production of materials that need to be sintered under non-oxidising environments. The total duration of the cycle, including heating, holding time and cooling is few seconds. Finally, some considerations about the scale up and possible industrialization of the technology are explained.Item Hard Metal Production by ERS: Processing Parameter Roles in Final Properties: Processing parameter roles in final properties(2019) Gallardo, José; Agote, Iñigo; Astacio, Raquel; Schubert, Thomas; Cintas, Jesús; Montes, Juan; Torres, Yadir; Cuevas, Francisco; EXTREMATCemented carbide is a hard composite material, used widely in a variety of industries. The value of the global tungsten carbide market is expected to grow by 4.4% (compound annual growth rate) from 2017 to 2022. One of the main markets is in metal cutting and wear parts, where small pieces (or inserts), a few grams in weight, are used. Field-assisted sintering technique (FAST) technologies allow for the production of small blanks in a single step from powder, which are near final dimensions. Production cycles are very short. In this paper, one of the FAST processes, the ERS technology, is applied to obtain WC10Co parts. A review of the process variable effects on the final properties of the parts is accomplished. Final properties of a range of conventionally produced inserts are obtained, using 100 MPa compacting pressure, 80 MA/m2 of current density, and processing times of around 800 ms.Item Production of Ultrafine Grained Hardmetals by Electrical Resistance Sintering(2019) Cintas, Jesús; Astacio, Raquel; Cuevas, Francisco; Montes, Juan; Weissgaerber, Thomas; Lagos, Miguel; Torres, Yadir; Gallardo, José; EXTREMATIn this work, powders of cemented ultrafine WC-6 wt.% Co were consolidated. The feasibility of the medium frequency electrical resistance sintering (MF-ERS) technique were studied to prevent WC grain growth during consolidation. Porosity and hardness were measured at different zones of the MF-ERS compacts. The compacts showed a slight inhomogeneity in their properties across their section, but it was controlled by choosing suitable values of the processing parameters. The optimal values for the material studied were current intensities between 7 and 8 kA and sintering times between 600 and 800 ms. The main achievement using this consolidation method was that sintered compacts essentially maintained the initial WC grain size. This was attained to processing times of less than 2 s, and without the need for using protective atmospheres.