Research Of Preparing W-Cu Nanocomposite By High-energy Ball Milling

The W-Cu composite is a kind of pseudo-alloy, which composed by tungsten component contributes the high melting point and high hardness and copper component contributes the high electric and thermal conductivity. Because of its resistance against electric arc erosion and fusion welding and its high degree of hardness and intensity, it is widely used with electric contacting material, electric resistance welding, electric spark manufacture, plasma electric pole material, electrothermal alloy and high density alloy, special lathe-hand material (such as air spout in rocket, throat-substrate in plane), central processing system in computer, leading wire frame in large scale compound integration, solid-stated microwave tube, etc.With the rapid development of science, all kinds of applications in reality require higher and higher performance on copper-tungsten composite. Because tungsten and copper do not dissolve each other, the preparation methods of W-Cu composite material proved particular. The material made by copper-tungsten nanocomposite powder possesses extremely high density (even nearly fully density) and so much high conduction of electricity and thermal that the materials made by normal methods can not be possess. The research selects the best manufacturing way—high-energy ball milling successfully preparing W-15wtCu nanocomposite powder, and then produce high-performanced W-Cu nanocomposite with ultrafine W grain uses pressing-liquid phase sintering method.The thesis investigates the W-Cu nanocomposite powder that prepared by high-energy ball milling, and analyzes the morphology and structure of the powder. The research is emphasized the effect of ball milling time and ball milling medium on W-Cu nanocoposite powder. W-Cu nanocomposite powder has been characterized: SEM analysis showed that tungsten and copper are homogenously mixed within each particle, the copper's average granularity is 0.3um, and there is partly aggregation of tungsten particle in the W-Cu nanocomposite powder. Besides, undersaturation solid solutions generate because of part copper dissolved by tungsten, tungsten and copper's average grain size is 39.7nm and 31.5nm separately calculated by XRD.At the same time, the relationship between technology and relative density of W-Cu nanocomposite has been detailed investigated. The research is emphasized the effect of ball milling time, sintering temperature, sintering pressure, sintering time, lubricant and impurity on density of W-Cu nanocomposite, and analyze the mechanism simply. Traditionally, "mixed powder, consolidation and liquid phase sintering" method can not be used to obtain fully density of W-Cu nanocomposite, however in this research it can be adapt to produce high-performanced W-Cu alloy by use of "high-energy ball milling powder, consolidation and pressing-liquid phase sintering" method. It obtains nearly fully density W-Cu nanocomposite in the best processing parameters, the density attains to 16.273g/cm~3, and its tungsten's average grain size is about 1um. The research provides some experimental foundations and bases for the industrialization and application of high-performanced W-Cu nanocomposite.