Technical Evolution of Ultrafine-grained Cemented Carbides: Mechanisms, Processes, and Limiting Strength

Ultrafine-grained cemented carbides (WC-Co) are critical materials for high-precision machining tools used in the electronics and automotive industries. This review systematically summarizes their technical evolution, focusing on the elucidation of grain growth inhibition mechanisms and the advancement of manufacturing processes. Historically, the fabrication of alloys with grain sizes below 0.2 µm was hindered by the difficulty of controlling abnormal grain growth during liquid-phase sintering. This barrier was overcome through two key breakthroughs: the development of direct carburization technology that produces uniform nano-sized WC powders, and the theoretical clarification that Vanadium Carbide (VC) inhibits grain growth via atomic adsorption rather than interface segregation. These advances enabled the realization of nano-grained hardmetals (