Ultrafast sintering of ultrafine-grained refractory metals at mild conditions

Refractory metals are promising candidates in aerospace, energy conversion, and high-temperature structural materials due to their exceptionally high melting points, superior mechanical properties, and excellent chemical stability. However, their formidable melting temperature and machining difficulties derived from high delocalized electron densitypose a severe obstacle in the development of refractory metal structure materials by traditional manufacturing. Herein, we discovered that liquid metals with high efficiency in dissolving refractory metal atoms could significantly dilute the delocalized electron density, weaken metal bonding, and act as a fast diffusion medium, thus realizing the fabrication of refractory metal bulk materials at a significantly lower temperature (<1000 °C) in a very short time (~2 min). Based on the sintering mechanism, we achieved the general sintering of refractory metal bulks (including W, Re, Ta, Nb, Mo, V, Cr, and Ti). Most notable are the equiaxed ultrafine-grained microstructures with excellent mechanical properties. Additionally, this mild approach offers high flexibility for tunable compositions and mass manufacturing, enabling the production of refractory metal alloy, gradient structure material, and carbide-dispersion-strengthened alloy. This research represents a significant milestone in developing high-performance refractory structural materials.