Enhanced Property of W-Cu Composites by Minor Addition of Ag

Nano-scale W-20Cu (mass%) and W-18Cu-2Ag (mass%) composite powders were obtained by mechano-thermochemical process, followed by liquid phase sintering process from 1200 to 1300 degrees C. The results indicate that the relative density and electrical conductivity of W-18Cu-2Ag composite were much superior to the W-20Cu composite at all temperatures. Microstructural investigation reveals that minor addition of Ag is beneficial to the densification of W-Cu composite. This can be ascribed to the stronger the wettability and capillary force of liquid Cu-Ag to W compared to that of pure Cu. Furthermore, during cooling Ag can precipitate into the voids between theW particles inW-rich area where is hard to be infiltrated by liquid Cu at high temperature, which is also beneficial to electrical conductivity.