Fabrication of gradient cemented carbide with Ni3Al binder: Simulations and experiments

Ni₃Al phase with an ordered fcc structure has been extensively investigated as alternative binder in WC/TiC/Ti(C, N)-based cermets. Due to the excellent stability, high temperature performance and oxidation resistance, it shows great potential in γ-free gradient cemented carbides. The possibility to fabricate WC-Ti(C,N)–Ni₃Al gradient cemented carbide using powder metallurgical method was investigated in the present work through both simulations and experiments. The alloys composition and sintering parameters were carefully designed with the guidance of thermodynamic calculations and DICTRA simulations. A gradient layer free of cubic Ti(C, N) phase and enriched in Ni₃Al binder at surface of the cemented carbide sintered at 1723 K for 2 h was generated, with thickness of about 20 μm. The microstructure, elemental concentration distributions and concentration profiles of the new-type gradient cemented carbide with Ni₃Al binder have been analyzed by means of XRD, SEM, EDS and EPMA. The gradient layer formation by DICTRA simulations is in accordance with the experimental data. The present work shows the potential for further design of the gradient cemented carbide with Ni₃Al binder under the powerful guidance of thermodynamic calculations and DICTRA simulations.