ABSTRACT
In order to discuss this result first the structure of heavy metal must be explained. Basically it consists of a tungsten phase and a binding phase which cements the tungsten particles together. The tungsten particles are normally much larger in size and more rounded in shape than what you would find in tungsten-copper as a result of significant grain growth through Oswald ripening during liquid-phase sintering (95,14). The tungsten phase of such alloys normallly has low contiguity of tungsten grains even though the volume percent of tungsten in the structure is high. The binding phase is lower melting than the tungsten phase but slightly higher than the melting point of copper, and therefore in this respect is similar to tungsten-copper. Another significant difference for this material from tungsten-copper is that the nickel and iron alloy with the copper and tungsten and thus the composite heavy metal material has a very low conductivity, < 10% of copper and about 1/5th the conductivity of the infiltrated tungsten-copper.
