Development of TiCN-Co-Cr₃C₂-Si₃N₄-based cermets with improved hardness and toughness for cutting tool applications

ABSTRACT

A TiCN-Co-Cr₃C₂-based cermet, with the addition of 5wt. % and 10wt. %Si₃N₄ and a reference sample without Si₃N₄ addition were prepared by the spark plasma sintering technique. The average hardness and fracture toughness of the 90TiCN-5Co-5Cr₃C₂(SN00) cermet-sintered specimens were e14.85±3.11 GPa and 6.78±0.61 MPaÖm, respectively. The cermet composition 85TiCN-5Co-5Cr₃C₂-5 wt. % Si₃N₄(SN05) enhanced the hardness and fracture toughness to 20.90±0.825 GPa and 7.23±0.45 MPaÖm, respectively. Further addition of 10 wt%Si₃N₄ with 80TiCN-5Co-5Cr₃C₂(SN10) decreased the hardness value to 16.18±0.279 GPa due to a decrease in the density of defects. However, the fracture toughness steadily increased to 9.34±3.10 MPaÖm. The cermet composition 85TiCN-5Co-5Cr₃C₂-5Si₃N₄ (SN05) showed an appreciable improvement in hardness and toughness values due to the formation of a core-rim structure, with the core consisting of TiCN and the rim with TiN, TiO₂, TiSi, Co₂C, CrN and Cr₂Si_.

KEYWORDS:

• TiCN cermets
• cutting tool
• hardness
• fracture toughness

Acknowledgements

Balasivanandha Prabu Shanmugavel thankfully acknowledges the fund (EEQ/2020/000620) received from the Science and Engineering Research Board, Department of Science and Technology, Government of India. The authors thank the Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai, India for providing the spark plasma sintering facilities for this work.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Science and Engineering Research Board [Grant Number EEQ/2020/000620].