Effect of carbide additions on grain growth in TiC-Ni cermets

초록

The growth of carbide particles ill TiC-XC-2 vol.% Ni and TiC-XC-30 vol.% Ni alloys, where X = Zr, Cr, W, Ta and Mo, was fitted to all equation of the form d(3)-d(0)(3) =Kt. The grain growth behavior during liquid phase sintering at 1673K decreased markedly with the addition of Mo2C or WC, changed little for TaC, and increased with the addition of Zl-C or Cl3C2. The grain contiguity decreased with increasing Ni content in the TiCMo2C-Ni alloy and was greater in the alloys with smaller growth rate constant. Consequently, the effect of carbide addition oil the grain growth of 2 vol.% Ni alloys was found to be similar to that of 30 vol.% Ni alloys. The grain growth mechanism could be explained by the effect of contiguous carbide grain boundaries in restricting the over-all grain growth, as well as the area of the solid/liquid interfaces in the alloy by the usual solution/reprecipitation model.

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