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Ti(C,N)基金属陶瓷的低韧性限制了其广泛应用于切削刀具领域。为探究碳纳米管对超细Ti(C,N)基金属陶瓷断裂韧性的影响,采用化学镀工艺在碳纳米管表面镀Ni,采用粉末冶金法真空烧结制备了不同碳纳米管含量的超细Ti(C,N)基金属陶瓷。研究了不同含量镀镍和未镀镍的碳纳米管对Ti(C,N)金属陶瓷组织和断裂韧性的影响。扫描电镜照片表明,添加CNTs后,组织中出现无芯晶粒及微孔洞。压痕法测试断裂韧性的结果表明,碳纳米管的加入使超细Ti(C,N)金属陶瓷的断裂韧性提高29.4%~62.7%,碳纳米管增韧机制为裂纹偏转和桥接增韧、无芯晶粒增韧及微孔洞增韧。此外,随着碳纳米管含量的增加,超细CNTs/Ti(C,N)金属陶瓷复合材料的相对密度和硬度均有轻微下降。添加镀镍和未镀镍碳纳米管对超细Ti(C,N)金属陶瓷都具有很好的增韧作用。
The low toughness of Ti (C, N) -based cermets limits their widespread use in cutting tools. In order to explore the effect of carbon nanotubes on the fracture toughness of ultrafine Ti (C, N) -based cermets, electroless plating was used to deposit Ni on the surface of carbon nanotubes. The ultrafine carbon nanotubes were prepared by vacuum sintering using powder metallurgy Ti (C, N) -based cermets. The effects of different contents of nickel and uncoated carbon nanotubes on the microstructure and fracture toughness of Ti (C, N) cermets were investigated. Scanning electron micrographs showed that after addition of CNTs, coreless grains and micropores appeared in the tissue. The result of indentation test of fracture toughness shows that the fracture toughness of ultrafine Ti (C, N) cermets increases by 29.4% -62.7% with the addition of carbon nanotubes. The toughening mechanism of CNTs is crack deflection and bridging toughening, Coreless grain toughening and micro-hole toughening. In addition, the relative density and hardness of the ultrafine CNTs / Ti (C, N) cermet composites decreased slightly with the increase of the content of carbon nanotubes. Adding nickel and uncoated carbon nanotubes have good toughening effect on ultrafine Ti (C, N) cermets.