Tungsten alloy has better function
In the development of filament materials, rhenium or cobalt can further improve the properties of W-Al alloy. When 3% Re is added, the elongation of WAl2 filament annealed at 2750 ℃ for 3 minutes can reach 25.7%. Even when the RE content is as low as 0.25%, the elongation can reach 6%; if 0.01-0.03% cobalt is added to the tungsten aluminum alloy, the bending ductility of the alloy wire is three times of that of WAl2 wire after annealing at 2700 ℃ for 5 minutes, and the shock resistance can be increased three times. Here, the role of cobalt is to increase the temperature of recrystallization and change the grain boundary shape after growth. In addition, cobalt also plays a deoxidizing role. When W-Co-1% THO2 alloy is used as filament, its anti spreading property increases ten times.
With the emergence of die casting technology and the development of Aerospace Engineering, people have created composite materials, that is, with molybdenum and tungsten as the skeleton, infiltrated with copper and silver with low melting point and good toughness (generally about 15%), in order to reduce the room temperature notch sensitivity and improve the cutting performance. This material has achieved good results in the use of small parts die casting mold. It can also be used as rocket nozzle material. At this time, silver or copper with low melting point is liquid at high temperature of about 3000 ℃, and continuously evaporates, playing a strong cooling role.
In addition, in semiconductor, radiation protection and metal die casting, the widely used high specific gravity alloy is made of tungsten and a small amount of nickel, iron or nickel, copper (generally equal, about 1-6% each) The function of nickel and iron is to improve machining performance (especially cutting performance) and room temperature ductility on the basis of ensuring the basic performance of tungsten. It should be pointed out that W-Ni-Cu alloy is not easy to make large section parts, because large section parts are easy to produce central brittle phase, which is caused by insufficient cooling speed, in addition, W-Ni-Fe alloy is magnetic.
