Synthesis Of W-15Cu High Density Alloy

W-Cu alloy have been used widely in the field of electrical materials, electron, war industry and spaceflight due to their high strenght and hardness, good electrical and thermal conductivity. However, because of the mutual insolubility between W and Cu, there are some difficulties of this kind of composites, such as, hard in melting, poor powder densification, and complex manufacturing process. Through carefully analyzing methods of producing nano-powders and the mechanisms of liquid phase sintering, we succseefully synthesize W-Cu composites powders by means of hydrogen reduction and produce high-performanced W-Cu alloy with ultrafine W grain in present work, which used the raw material is tungsten blue oxide (TBO) and Cu(NO₃)₂. In this dissertation, the following research aspects have been accomplished.W-Cu composites powders is synthesized by means of hydrogen reduction process, includeing three steps: burn out ball milling and hydrogen reduction. Since there are many processing paremeters in each step, which can influence the morphology and structure of the corresponding powders, the research is emphasized on the hydrogen reduction step studying the phase formation sequence and the effect of temperature and atmosphere on the phase as well as W grain size of W-Cu composites powders.The sintering behavior of the W-Cu composites powders have been carefully investigated. Traditionally, "powders consolidation and liquid phase sintering"method can not be used to obtain full density W-Cu alloy due to the coarse-grained W and Cu powders, however in this work it can be adopted to produce near full density alloy using W-Cu composites powders as the starting materials. Base on the relationship between blank density and sintering temperature, a densitycation mechanism, named "densification induced by rearrangement", has been proposed and it can well explain the sintering behavior of the W-Cu composites powders. The production of every period and W-Cu alloy are investigated by using SEM and XRD to analyse their phase, organization and property. The results show that the W-Cu composite powders produced by these processes have homogeneous chemical composition and high sintering activity. A high sintered density can be achieved at the lower temperature. The relative density of W-Cu alloy sintered in 1220℃for 2h is 98.45%. The Cu net structure is achieved ,which is favour of electricity and heat conduction.