陶瓷相原始粉末粒度对Ti（C，N）基金属陶瓷组织和性能的影响

采用粉末冶金法制备了超细晶Ti（ C， N）基金属陶瓷和纳米改性Ti（ C， N）基金属陶瓷试样和刀具。研究了陶瓷相粉末粒度对Ti（ C， N）基金属陶瓷显微组织、力学性能及其刀具耐磨损性能的影响。结果表明，超细晶Ti（ C， N）基金属陶瓷和纳米改性Ti（ C， N）基金属陶瓷的硬质相均具有黑芯/灰壳和白芯/灰壳两种显微结构。超细晶Ti（ C， N）基金属陶瓷中白芯/灰壳结构硬质相晶粒较多，而纳米改性Ti（ C， N）基金属陶瓷中硬质相晶粒主要为黑芯/灰壳结构。与超细晶Ti（ C， N）基金属陶瓷相比，纳米改性Ti（ C， N）基金属陶瓷具有较高的抗弯强度和断裂韧度以及较低的硬度和孔隙度。纳米改性Ti（ C， N）基金属陶瓷刀具具有较长的使用寿命，约为超细晶Ti（ C， N）基金属陶瓷刀具使用寿命的2．3倍。

Effect of Starting Powder Size of Ceramic Phase on Microstructure and Properties of Ti（ C, N）-based Cermets

The ultra-fine grain and nano-modified Ti （ C, N）-based cermet samples and cutters were prepared by powder metallurgical practice .The effect of ceramic powder size on microstructure , mechanical properties of Ti （C, N）-based cermets and wearability of the cutter was investigated .The results show that both the hard phases of ultra-fine grain and nano-modified Ti（C, N）-based cermets offer all the microstructure consisting of black core /grey rim and white core/grey rim.The ultra-fine Ti （ C, N）-based cermet contains many hard phase grains with white core/grey rim, whereas the hard phase grains of nano-modified Ti（C, N）-based cermet is mainly the black core/grey rim structure.Relative to the ultra-fine grain Ti（C, N）-based cermet, the nano-modified Ti（C, N）-based cermet gives higher bending strength and fracture toughness , and lower hardness and porosity .The service life of nano-modified Ti（C, N）-based cermet cutter is longer and is about 2.3 times that of ultra-fine grain Ti（C, N）-based cermet cutter .