Thermal and mechanical properties at high temperature of Co-based superalloys strengthened by MC Carbides with M=Ta or Nb
Résumé
Introduction:
Polycrystalline Co-based superalloys strengthened by carbides can be used at high temperature above 1100°C.
These alloys are the most often mechanically reinforced by TaC carbides.
But versions involving MC carbides can be strengthened by other carbides as Nb, Ti, Zr or Hf carbides.
In this work, the effects of the presence of niobium carbides in a Co-based superalloy on its thermal and mechanical properties were studied.
The results are compared with those of a more classical Co-based superalloy reinforced by tantalum carbides.
The influence of aging was also studied for the two alloys (strengthened by NbC and by TaC).
Conclusion:
TaC and NbC are stable in Co-based superalloys: it is possible to have sustainable TaC or NbC in a Co-based alloy.
The alloy strengthened by TaC is more mechanically resistant than the CoNb alloy.
However, these alloys are not suitable for uses at 1200°C and also 1150°C for the CoNb alloy.
The CoNb alloy led to better properties than for the same Ni-based alloy: the Co-based alloys can be used to produce materials which must present good mechanical behaviour at high temperature (1100°C-1150°C) instead Ni-based alloys and maybe furthermore to compete with γ/γ’ superalloys.
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098 POSTER BeyondNiBasedSuperalloysII 2016 MR PB.ppt [Mode de compatibilité].pdf (3.58 Mo)
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