Fabrication of W–Cu functionally graded materials with high density by particle size adjustment and solid state hot press

A new technology for fabricating W–Cu functionally graded materials was developed. In order to get nearly full density, a tailored particle size distribution of W powder was selected for the layer with high W content. The compacts with three layers were hot-pressed at temperature below the melting point of Cu to keep the adjusted graded design. The effects of fabricating parameters, including sintering temperature, pressure and holding time, on the density, hardness and microstructure of the graded materials have been investigated. The results show that a dense microstructure is obtained when the W particle distribution is 80%A + 20%B (A and B denote large W particle powder and small W particle powder, respectively) in the layer with high W content. W–Cu functionally graded materials with nearly full density can be fabricated by the foregoing method. The interface linking each layer is visible, and the layer itself has high density. The component of initial graded design can be kept stable.