Effects of sintering temperature and nano Ti(C,N) on the microstructure and mechanical properties of Ti(C,N) cermets cutting tool materials with low Ni-Co

Abstract

The improvements of mechanical property as well as the microstructure of Ti(C,N) cermets cutting tool materials were presented. The influences of sintering temperature and nano Ti(C,N) had been studied. As rising the sintering temperature, the microstructure of Ti(C,N) cermets gradually became well-distributed, besides, the rim structure was gradually completed. The flexural strength improved obviously, but the changes of the hardness and the fracture toughness were relatively small. Nano Ti(C,N) had remarkable influence on the mechanical properties of Ti(C,N) cermets. The grain growth could be repressed by the addition of nano Ti(C,N). In the refinement microstructure, there were two typical core-rim structure, including a dark core with grayish rim structure and a bright core with grayish rim structure, besides, the formation mechanisms were both investigated. The flexural strength increased, nevertheless, the fracture toughness was slightly reduced, and the hardness kept constant. The fracture surface and crack propagation indicated that most cermets with coarse grains were easy to cause the transcrystalline fracture, meanwhile the intercrystalline fracture had the tendency to occur more in cermets with finer grains.