用固溶体和单组元为原料制备的 Ti（C,N）基金属陶瓷的组织与性能

摘要

Using solid solution type TiC0.7N0.3 and interstitial phase type TiC and TiN as raw materials, the TiC0.7N0.3–10WC–4Mo2C–3TaC–2.4Cr3C2–10Ni–10Co and TiC–10TiN–10WC–4Mo2C–3TaC–2.4Cr3C2–10Ni–10Co cermets were prepared by sinter-HIP at the temperature of 1 440 ℃ under a pressure of 6 MPa. The microstructures and mechanical properties were observed and tested. The results show that although there are differences in the relative contents of the chemical components of the hard phase and binder phase, both the Ti(C,N)-based cermets have the same phase composition. The hard phase is a cubic structured single-phase carbonitride containing Ti, W, Mo, Ta and Cr. As compared with monocomponent raw materials, the cermet prepared from TiC0.7N0.3 has homogeneous microstructure, finer grain size, more regular and stable core–rim structure, well coated core, thinner rim, lower Ti,Ta content and lower solid solubility in the binder phase, and accordingly much better mechanical properties. The differences in the microstructure and properties are explained in terms of the accelerant-linkage effect related with the binder phase and the degree of order in reaction-diffusion during the reaction-sintering process.%　　分别采用固溶体型 TiC0.7N0.3和间隙相型单组元 TiC、TiN 为原料，制备 TiC0.7N0.3-10WC-4Mo2C-3TaC-2.4Cr3C2-10Ni-10Co 和 TiC-10TiN-10WC-4Mo2C-3TaC-2.4Cr3C2-10Ni–10Co 2种 Ti(C,N)基金属陶瓷，观察与分析这2种金属陶瓷的微观组织结构和力学性能。结果表明，尽管这2种金属陶瓷的硬质相与粘结相中化学组元的相对含量存在差异，但具有相同的物相成分，其中硬质相为含 Ti、W、Mo、Ta、Cr 的立方结构碳氮化物。与单组元原料相比，用固溶体型原料制备的金属陶瓷的微观组织结构均匀，硬质相的晶粒相对细小、芯–环结构完整、环部厚度适中，粘结相中 Ti 和 Ta 的含量与固溶度都较低，综合力学性能显著提高。从反应烧结过程中粘结相“触媒–联动”效应与反应扩散有序度的角度对这2种金属陶瓷的微观组织结构与性能的差异进行解释。