Fabrication of nanocrystalline and ultra-hard tungsten alloy by dual-particle dispersion strengthening

Alloying with heterogeneous atoms or second phase particles is an effective method for inhibiting grain growth and achieving ultrafine and nanocrystalline materials. In this work, by varying the component and content of Ti and ZrC, the synergistic effects of dual-particle reinforcement on sintering behavior and final bulk W alloys were investigated. The results revealed that adding both Ti and ZrC not only dramatically suppresses grain growth but also effectively promotes relative density. Nanocrystalline W-3Ti-1ZrC bulks were successfully fabricated with an ultra-high hardness of 1347 kgf/mm2. Further characterization showed that the alloying component and content strongly influence the milled-powder state agglomeration and morphology even in same milling condition. Additionally, the advantage of Ti and ZrC addition can be utilized simultaneously, as Ti retards grain growth and ZrC reacts with oxygen impurities to enhance grain boundary cohesion.