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Preparation of high-entropy carbides by different sintering techniques

 
: Pötschke, Johannes; Dahal, Manisha; Herrmann, Mathias; Vornberger, Anne; Matthey, Björn; Michaelis, Alexander

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Journal of Materials Science : JMS 56 (2021), No.19, pp.11237-11247
ISSN: 0022-2461
ISSN: 1573-4803
English
Journal Article, Electronic Publication
Fraunhofer IKTS ()
carbides; High Entropy Carbides; microstructures; mechanical properties

Abstract
Dense (Hf-Ta-Nb-Ti-V)C and (Ta-Nb-Ti-V-W)C based high entropy carbides (HEC) where produced by three different sintering techniques: gas pressure sintering or sinter-HIP at 1900 °C and 100 bar Ar, vacuum sintering at 2250 °C and 0.001 bar and SPS/FAST at 2000 °C and 60 MPa pressure. The relative density varied from 97.9% to 100%, with SPS producing 100% dense samples with both compositions. Grain size measurements showed that the (Hf-Ta-Nb-Ti-V)C HEC's had 5-10 times smaller grain size than the (Ta-Nb-Ti-V-W)C samples. Vacuum sintered samples showed the biggest but uniform HEC grain size distribution regardless of compositions. EDS mapping showed the formation of a solid solution with no intermetallic phases or element clustering. X-ray diffraction analysis, showed the formation of single-phase cubic high entropy carbides with a unique lattice parameter for all samples. Hardness measurement revealed that (Hf-Ta-Nb-Ti-V)C samples possess higher hardness values than (Ta-Nb-Ti-V-W)C samples.

: http://publica.fraunhofer.de/documents/N-634261.html