Mechanical properties and microstructure of Ti(C, N) based cermet cutting tool materials fabricated by microwave sintering

摘要

A type of Ti(C, N) based cermet cutting tool materials was fabricated by microwave sintering. The effects of metal content and sintering temperature on the mechanical properties and microstructure were thoroughly investigated. The experimental results showed that sufficient metal liquid phase can significantly improve densification and fracture toughness of cermet. However, high metal content, on one hand, reduced the hardness of cermets, and on the other resulted in the micro-defects of materials. The activate mechanisms of microwave can lower the temperature required for the metal liquid phase formation and enable the densification of cermet at low temperatures without external pressure. But low sintering temperature suppressed the flow of metal liquid phase which caused the pores among the grains cannot be fully filled. High temperature may lead to the coarsening of the particles and the decreasing of mechanical properties. A Ti(C, N) based cermet cutting tool material with 15% Co-Ni content which was sintered at 1550 degrees C for 10 min exhibited the optimum mechanical properties. Its hardness and fracture toughness were 15.49 +/- 0.21 GPa and 10 +/- 0.55 MPa m(1/2) respectively. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.