Research and development status of sintering technique of ultrafine/nano WC-based cemented carbide

WC-based cemented carbides with ultrafine and nano grain sizes have the ultrahigh strength, hardness and toughness, which are widely applied in the automotive, aerospace, defense, and other fields of modern manufacturing. However, the small particle size and high activity of ultrafine/nano WC powders are extremely easy to grow up during the preparation of cemented carbides, and controlling the rapid coarsening of ultrafine/ nano WC powders during sintering has become a great challenge. To obtain ultrafine and nanocrystalline WC-based cemented carbides, the latest research progress in terms of raw material powder preparation, novel sintering technology development, grain growth inhibitor addition and new cemented carbide design were reviewed. The grain size of WC powders obtained by optimized powdering and sintering processes, and the mechanical properties of the sintered alloys were analyzed. Furthermore, the influences of various grain growth inhibitors on the microstructure and properties of WC-based cemented carbides were compared. Then, novel sintering methods, such as low-pressure hot isostatic pressing sintering(Sinter-HIP) and spark plasma sintering(SPS) and microwave sintering(MS), were compared. The ultrafine and nanocrystalline microstructure and properties were reviewed through the typical new type cemented carbide, including binderless cemented carbide and composite with high entropy alloy(HEA) bonder. The development prospect and research emphasis of ultrafine/nano WC-based cemented carbide were prospected, which provides a new method for the development of modern ultrafine/nano cemented carbide. © 2024 Central South University of Technology. All rights reserved.