Powder metallurgical processing and properties of copper/tungsten gradients

A graded composition of Copper and Tungsten offers the chance for the application of materials which combines on one side high thermal and mechanical resistance and on the other side high thermal and electrical conductivity. W/Cu gradient materials were produced by Centrifugal Powder Forming. Thereby the possibility of mixing variations for the development of gradient materials with different concentration limits, different exponents of gradient function and also for pore structure gradients can be used. Because of the difference in the sintering behaviour the consolidation has to be adapted to the concentration areas. With the aim to produce dense sintering bodies liquid phase sintering, activation of sintering by additives and the HIP process as well as the infiltration of porous Tungsten parts with porosity gradient were used. Dilatometry, the investigation of microstructure and neutron diffraction measurements enable the characterisation of density and material composition development, thermal expansion and thermal stresses. The advantages and limits of the powder technology will be discussed in connection with the material properties.