Densification, microstructure, and properties of W-Mo-Cu alloys prepared with nano-sized Cu powders via large electric current sintering

This study rapidly fabricated a novel W-Mo-Cu alloy by large current electric field sintering at a relatively low temperature, and the effects of the powder size of Cu on the densification, microstructure, and properties were comprehensively investigated. The particle size of Cu did not influence the phase type but significantly affected the densification, microstructure, and properties. XRD and TEM results showed that the alloy contained three new phases aside from W, Mo, and Cu phases, i.e., Mo-W ordered phase, Mo-Cu solid solution, and Cu0.4W0.6 intermetallic compound. Copper powders with smaller sizes were beneficial to improving the distributional homogeneity of elements and the sintering densification. Therefore, the alloy prepared with 100 nm Cu powders had a denser and more homogeneous microstructure and better comprehensive properties than that prepared with 5 μm Cu powders. Overall, the W-Mo-Cu alloy prepared with 100 nm Cu powders at 980 °C proposed the best comprehensive properties, and its relative density can reach 98% approximately.