Effect of Mo2C Addition on the Microstructure and Properties of TiC-High Manganese Steel-Bonded Carbide

Abstract

TiC-high manganese steel-bonded carbide was prepared by powder metallurgy method with varied Mo2C content (0, 2.5%, 5%, 7.5% and 10% respectively), and the effects of Mo2C addition on the microstructure and mechanical properties of the fabricated cermets were studied. The microstructures of the fabricated cermets were observed and analyzed by scanning electron microscope (SEM), and the physical and mechanical properties of the cermets were also tested. The results show that the microstructure of the cermet without Mo2C additive was finer than that of the cermets with 2.5% and 5% Mo2C addition, though Mo2C was an effective grain growth inhibitor of TiC- and/or TiCN-based refractory materials because of low inherent solubility of TiC in Fe binder. An interesting phenomenon was also found that black core-gray rim was observed in the microstructure of the cermet without Mo2C addition. The microstructure of the fabricated cermets was fine with the increase of Mo2C content. The results also show that the relative density and hardness of the cermet increased monotonously with the increase of Mo2C content, hence, the transverse rupture strength (TRS) and impact toughness (IM) of the fabricated cermets increased first and then decreased, and the TRS and IM reached the maximum valve of 2189 MPa and 11.7 J/cm2 when Mo2C content was 7.5% and 5% respectively.