Sintering and mechanical properties of nanoscaled W-40%Cu alloys

The densification of nanoscaled W-Cu powder was investigated through measurements of the shrinkage kinetic curves in hot pressing and hydrogen sintering and compared with that of nanoscaled W powder and traditional Cu powder. The resulted alloys were subjected to hot compression tests at 300℃ and 500℃ to obtain their stress-strain curves. It is indicated that the temperature corresponding to the highest shrinkage rate of nanoscaled W-Cu powder is 980℃ in hydrogen sintering. After sintering at 1200℃, the mean grain size of W phase is less than 2 μm, and the relative density of the alloy is 97%. In hot pressing, however the corresponding temperatures is 930℃. The mean grain size of W phase in the hot pressed alloy from nanoscaled W-Cu powder is 0.5μm at 1 200℃, and its relative density is 98%. The results of hot compression tests at 300℃ and 500℃ showed that the high-temperature strength of the ultrafine grained W-Cu alloy is higher than that of the alloy sintered from nanoscaled W powder and traditional Cu powder.