TaC对Ti(C,N)-Ni基金属陶瓷的组织和性能的影响

Effect of TaC on the Microstructure and Properties of Ti(C,N)-Ni Based Cermets

通过热力学计算和实验相结合的方法研究TaC对Ti(C,N)-Ni基金属陶瓷的微观结构和性能的影响。结果表明,Ti(C,N)-TaC-Ni金属陶瓷的显微结构呈现"黑芯-白内环-灰外环"的包覆结构。随着Ta的加入,粘结相的体积分数增加。由于Ta的存在会抑制Ti原子在液相的溶解和析出,使得陶瓷晶粒得到细化,这有利于提高金属陶瓷硬度,但是断裂韧性会降低。TaC引入Ti(C,N)-Ni基金属陶瓷中改善了合金的抗氧化性。在800℃空气中恒温氧化12 h后,质量分数为18%的TaC的金属陶瓷的抗氧化性提高了86.19%。

The effects of TaC content on the microstructure and properties of Ti(C,N)-Ni based cermets are systematically investigated by a combination of thermodynamic calculations and experiments. The results show that the microstructure of Ti(C,N)-TaC-Ni cermets consist of black core, white inner rim and grey outer rim. When Ta is added to the cermet, the volume fraction of the binder phase increases. And the presence of Ta suppresses the dissolution and precipitation of Ti atoms in the liquid phase, which results in a decrease in ceramic grains size. This is benefical to increase the hardness of the cermet, but the fracture toughness decreases. The introduction of TaC into the Ti(C,N)-Ni based cermets improves the oxidation resistance of the alloy. Particularly, the oxidation resistance of cermets containing 18% TaC is improved by 86.19% after oxidization at800 °C in air for 12 h.