Effect of secondary carbides on the core-rim structure evolution of TiC-based cermets

Herein, the effect of adding VC with different contents and Mo2C, WC and TaC on the core-rim structure evolution of TiC-based cermets was investigated using x-ray diffraction, scanning electron microscopy and energy-dispersive spectroscopy. Results show that the added secondary carbides exhibiting the same crystal stucture as TiC are prone to solid dissolution in TiC grains and change the core-rim stuctures of TiC-based cermets. With the addition of only VC, (Ti,V)C is the main component in the black core-grey rim structure and increasing the VC content is beneficial for promoting the dissolution process of cores. With the addition of multiple carbides, the core-rim structure in cermet Ta-7 is effectively improved, showing a high percentage of white core-grey rim structures, and the mechanical properties are improved.