This study realized modulation of size and content of metallic nanoparticles inside ceramic grains of cermets using WC-Co cemented carbides as an example. The approach was based on tailoring the composition of the in-situ reactants of synthesizing ceramic-metal composite powders. With the optimized size and content of nanoparticles distributing in WC grains, simultaneous improvement in hardness, strength, and fracture toughness was achieved in the prepared WC-Co cemented carbides, and the integrated mechanical properties reached the highest among the cermets with similar compositions reported in the literature. The effect of metallic nanophases in ceramic grains on the microscale stress and strain distributions of the cermets was quantitatively investigated. Detailed characterization and analysis of the interactions between the metallic nanophases and ceramic dislocations revealed that these nanophases hindered dislocation motion but did not cause local stress concentration and microcrack nucleation, hence enabled to concurrently strengthen and toughen the ceramic grains. This study provides a unique method and quantitative guideline for developing cermets with superior integrated mechanical properties, particularly important for cermet materials with low metal contents.

中文翻译：

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陶瓷颗粒中金属纳米颗粒的微尺度应力分布及其对金属纳米陶瓷力学性能的影响


本研究以 WC-Co 硬质合金为例，实现了对金属陶瓷晶粒内金属纳米颗粒尺寸和含量的调制。该方法基于定制合成陶瓷-金属复合粉末的原位反应物的组成。随着 WC 晶粒中分布的纳米颗粒的尺寸和含量的优化，所制备的 WC-Co 硬质合金的硬度、强度和断裂韧性同时得到提高，并且综合力学性能在文献报道的类似成分的金属陶瓷中达到最高。定量研究了陶瓷晶粒中金属纳米相对金属陶瓷微观应力和应变分布的影响。对金属纳米相和陶瓷位错之间相互作用的详细表征和分析表明，这些纳米相阻碍了位错运动，但不会导致局部应力集中和微裂纹成核，因此能够同时强化和增韧陶瓷晶粒。本研究为开发具有卓越综合机械性能的金属陶瓷提供了一种独特的方法和定量指南，这对于金属含量低的金属陶瓷材料尤为重要。