Excellent mechanical, thermal and electrical properties of ultrafine W-Cu alloys via freeze-drying technology

In order to further refine W particles and improve properties of traditional W-Cu alloys, an innovative freeze-drying and subsequent solid phase sintering technology was employed to fabricate ultrafine W-10/20/30Cu alloys in our work. Compared with W-Cu powder precursors synthesized by traditional technologies, the freeze-dried powders (35 nm) are finer and better dispersed, which possess ultrahigh sintering activity. After solid phase sintering, the relative density of prepared W-Cu alloys is as high as above 98%. Meanwhile, the Cu network possesses complete continuity and the W particles keep ultrafine size (178 nm), which is much smaller than W particles in W-Cu literatures. Compared with other traditional technologies, freeze-dried W-Cu alloys in our work possess the highest hardness (499 HV_0.2), taking into account high thermal conductivity (246.9 W/mk) and electrical conductivity (48.3% IACS), which provides a new insight for the further development of W-Cu alloy industries.