Monday, December 24, 2012

Tungsten Alloy

Tungsten Alloy

tungsten alloy
Tungsten alloy, also named tungsten heavy alloy, generally is refractory metal, which have two-phase composites consisting of W-Ni- Fe or W-Ni- Cu or even W-Ni-Cu-Fe, some tungsten alloys are added CoMoCr, etc. They have very high melting point and have a density twice that of steel and are more than 50% heavier than lead. Tungsten content in conventional heavy alloys varies from 90 to 98 weight percent and is the reason for their high density (between 16.5 and 18.75 g/cc). Nickel, iron and copper serve as a binder matrix, which holds the brittle tungsten grains together and which makes tungsten alloys ductile and easy to machine. Nickel-iron is the most popular additive, in a ratio of 7 Ni: 3Fe or 8Ni: 2Fe (weight ratio). The conventional processing route for tungsten heavy alloy includes mixing the desired amount of elemental powders, followed by cold pressing and  liquid phase sintering to almost full density. 
 

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