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Microstructure and mechanical properties of NbC matrix cermets using Ni containing metal binder

  • : Shuigen Huang1, Jozef Vleugels1, Kim Vanmeensel1, Mathias Woydt2, Hardy Mohrbacher3
  • : 1MTM, KU Leuven, 2BAM Federal Institute for Materials Research and Testing, 3NiobelCon bvba
  • : PDF Download
  • : 2015


The current study reports the addition of Al metal and secondary refractory carbides on the microstructure and mechanical properties of Ni bonded NbC matrix cermets. Powder mixtures were pressurelessly sintered for 1 h at 1420°C in vacuum. Microstructural and elemental mapping of the sintered cermets were performed by electron probe microanalysis (EPMA) to reveal the effect of those additions on NbC grains morphology, grain growth and binder composition. Results indicated that NbC grain growth was suppressed and homogeneous NbC grain size distribution was obtained in the cermets with the addition of Al and secondary carbides, i.e. Mo2C + VC + WC, as compared to the pure Ni binder. The liquid phase sintered NbC-12 vol% Ni cermet had a Vickers hardness (HV10) of 1128 ± 22 kg/mm2 and indentation toughness of 11.87 ± 0.42 MPa m1/2. With the addition of 4 vol% WC-4 vol% VC-4 vol% Mo2C, the hardness increased to 1491 ± 15 kg/mm2, whereas the corresponding toughness decreased to 9.15 ± 0.40 MPa m1/2. Addition of 3.6 wt% Mo2C into WC-40 wt% NbC 12 wt% Ni mixture increased further the hardness of sintered cermet to 1619 ± 19 kg/mm2 in combination with a moderate fracture toughness of 7.76 ± 0.20 MPa m1/2.


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