Preparation of bulk Cu-W interpenetrating-phase composites by liquid metal dealloying

Abstract

Copper-Tungsten (Cu-W) composites are promising materials for electrical and thermal applications. Manufacturing the desired Cu-W composites with full densification and a homogenous microstructure remains difficult, however, owing to the lack of mutual solubility, poor wettability, and the large difference in melting temperature between W and Cu. Here, a fully dense homogenous bulk Cu-W composite with a three-dimensional bicontinuous interpenetrating-phase architecture is fabricated by liquid metal dealloying (LMD) method, which involves immersing the Ni-W alloy in a molten metal Cu bath. The microstructure evolution mechanisms and the dealloying kinetics from a Ni-W precursor alloy to Cu-W composite are investigated. The synthesized Cu-W composite structure showed morphology variations depending on the dealloying time. The coarsening mechanism of the W ligaments during dealloying were analyzed based on curvature-driven surface smoothening and Rayleigh instability controlled ligament pinch-off process.