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Cemented carbides based on WC pre-alloyed with Cr or Ta

Jonathan Weidow (Institutionen för teknisk fysik, Materialens mikrostruktur ) ; A. Blomqvist ; J. Salomonsson ; S. Norgren
International Journal of Refractory Metals & Hard Materials (0263-4368). Vol. 49 (2015), p. 36-41.
[Artikel, refereegranskad vetenskaplig]

WC powder pre-alloyed with Ta or Cr was used to produce WC-Co based cemented carbides and these were compared with materials produced from pure WC. Atom probe tomography analysis of the pre-alloyed as-sintered materials showed that a high, non-uniform, concentration of Ta or Cr remained in the WC lattice after sintering. The hexagonal (W,Ta)C partially decomposes during sintering leading to the formation of a fcc MC phase. Similarly, the (W,Cr)C partially decomposes, but no Cr-rich precipitates were observed in either of the Cr containing samples. The hardness of the crystallites of the doped materials was significantly lower than the undoped WC, as measured by nano-indentation. The Young's moduli of the doped crystals were significantly lower than the undoped WC in agreement with the lowering of the elastic constants, from ab initio calculations. The microhardness (HV) reflected what would be expected from the average WC grain size giving that the grain boundary surface area is more important for the material hardness than the hardness of the WC crystals themselves in the investigated grain size range.

Nyckelord: APT, EBSD, Grain size, Hardness, Coercivity



Denna post skapades 2015-07-06.
CPL Pubid: 219453

 

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Institutioner (Chalmers)

Institutionen för teknisk fysik, Materialens mikrostruktur (2012-2015)

Ämnesområden

Teknisk fysik

Chalmers infrastruktur