Copper, nickel and tungsten powders are used in the production of so called heavy metal, which contains from 80% to 95% tungsten. The alloys are prepared by the liquid-phase sintering of mixed elemental powders during which part of the tungsten dissolves in the copper-nickel liquid. The product is a two-phase material consisting of rounded tungsten grains and a matrix of copper-nickel-tungsten containing up to 17% tungsten.
The density of the alloys ranges from 17-18 g/cm 3 and the electrical conductivity is quite low, on the order of 17% IACS. The mechanical properties are strongly influenced by the nickel-copper ratio and by the post-sintering heat treatment. Tensile strengths range from 45-125 ksi (310-862 MPa) and elongations from 2% to 8%.
These alloys are used in such applications as gyro rotors, instrument counterweights, airframe counterweights, jet aircraft wing edges and balancing weights for rotating elements in machinery, golf clubs and self winding wrist watches.