The effect of the content of carbide on the mechanical properties of Ti(C,N) based cermet

Ti(C,N)-Mo2C-Cr3C2 system cermet with a low content Of Mo2C and Cr3C2 was fabricated by hot pressure technology. The mechanical properties and SEM microphotography of fracture surface and indention crack propagating on ground surface of the Ti(C,N) based cermet were discussed. It is shown that the fracture modes of the fabricated materials are mainly intergranular fracture, the flexural strength of the materials is closely related to the thickness of Rim phase, and the cermet with a content of 8wt.% Mo2C has high flexure strength owing to moderate thickness of Rim phase. It is also demonstrated that the cermet with a content of 1.6wt.% Mo2C possesses high fracture toughness due to shorter crack path, crack deflection and crack branches. It was found that the flexure strength increases with the content of Cr3C2. The cracks exist on the interface between Cr3C2 and Ti(C,N) due to tensile stress and result in a decrease of crack propagating resistance, thus the fracture toughness of the cermet deeply decreases with the increase of Cr3C2 content when Cr3C2 content is more than 8wt.%.