纳米硬质合金的可控制备是高端切削工具领域面临的国际难题，如何有效调控致密化过程中晶粒长大是制备纳米硬质合金的关键所在。为此，本项目提出了通过设计具有核壳结构(WC为核、Cr2(C,N)为内壳层、Co为外壳层)的WC-Cr2(C,N)-Co纳米复合粉，改善晶粒长大抑制剂、N元素和粘接相Co在合金组织中的分布，来抑制WC-Cr2(C,N)-Co合金中WC晶粒长大，优化合金的微观结构与性能，实现合金强韧化的新思路。并着重研究：(1)采用水热合成、喷雾转化技术、并结合碳热还原氮化工艺，可控制备核壳结构WC-Cr2(C,N)-Co纳米复合粉；(2)探讨WC-Cr2(C,N)-Co核壳结构的形成机理；(3)揭示该核壳结构复合体系的烧结致密化行为与冶金机制；(4)结合计算机模拟计算，阐明核壳结构抑制WC晶粒长大、强韧化合金的作用机理。本项研究将为高性能纳米硬质合金的可控制备提供有效的理论依据和技术支撑。

How to controllable fabricate the nanocrystalline hardmetals, of which the key challenge is to control the rapid grain growth during the fully densifying, have become an international problem in the field of high-end cutting tools. Therefore, in this project, the innovation is proposed that through design novel WC-Cr2(C,N)-Co core-shell structure (WC as the core, Cr2(C,N) as the inner rim, Co as the outer rim) nanocomposite powders, in order to improve the distribution of grain growth inhibitors, nitrogen and binder Co in hardmetals, which will enhance the inhibition performance on WC grain growth, optimize the microstructure and mechanical properties, and strengthen and toughen the nanocrystalline hardmetals. The main research in this work focus on: (1) controllable preparing the WC-Cr2(C,N)-Co core-shell structure nanocomposite powders, by using the hydrothermal synthesis, spray transformation method and the carbon thermal reduction nitride technology; (2) unfolding the formation mechanism of the WC-Cr2(C,N)-Co core-shell structure; (3) revealing the sintering densification behavior and metallurgy mechanism of the core-shell structure nanocomposites; (4) explaining the acting mechanism of the core-shell structure in inhibiting the WC grain growth and the strengthening-toughening hardmetals, combining with the calculations and simulations. This project will provide theoretical basis and technical support for the preparation of high-performance nanocrystalline hardmetals.