颗粒弥散和核-壳共存的TiCN基金属陶瓷的制备

为了制备具有良好综合力学性能的TiCN基金属陶瓷，研究了烧结温度对TiCN-HfN陶瓷微观结构和力学性能的影响，构建了颗粒弥散和核-壳共存的微观结构模型，揭示了材料的致密化机制、增硬机制、增韧补强机制。结果表明:在1 500℃下所制备的TiCN-HfN材料具有颗粒弥散与核-壳共存的微观结构，其中弥散的颗粒为HfN，核为TiCN，壳主要为(Ti, Hf, Mo)CN固溶体；材料具有较好的性能，其相对密度为99.7%、硬度为20.6 GPa、抗弯强度为1 682.5 MPa、断裂韧度为8.5 MPa·m1/2；其致密化机制主要为颗粒和金属液相填充到烧结颈实现致密化，增硬机制主要为致密化和颗粒钉扎强化增硬，增韧补强机制主要为颗粒弥散和颗粒钉扎增韧、骨架结构和颗粒钉扎增强。 

Fabrication of TiCN-based cermet with a coexisted microstructure of particle dispersion and core-rim structure

In order to fabricate the TiCN-based cermet with better comprehensive mechanical properties, the effects of the sintering temperature on hte microstructure and mechanical properties of TiCN-HfN cermet were investigated. And a model of a coexisted microstructure of particle dispersion and core-rim structure was built for this cermet. Meanwhile, the densification, hardened, toughened and strengthened mechanisms were disclosed. The results show that the TiCN-HfN cermet fabricated at 1 500℃ has this coexisted microstructure and better comprehensive mechanical properties. The dispersed particle is HfN, the core consists of TiCN, and the rim is mainly composed of (Ti,Hf,Mo)CN solid solution. The relative density, hardness, flexural strength and fracture toughness of this cermet are 99.7%, 20.6 GPa, 1 682.5 MPa, 8.5 MPa·m1/2, respectively. This cermet completes densification by particles and metal liquid that filled in the sintering necks in the cermet. This cermet is hardened by its densification and particle pinning effect, and is toughened by particle dispersion and particle pinning effect, and is strengthened by the formed skeleton structure and particle pinning effect.