Process of high-density tungsten alloy

MIRAMAR, Fla. - April 27, 2022 - PRLog -- High-density tungsten alloy (https://www.edge-techind.com/Products/Refractory-Metals/Tungsten/Tungsten-Alloys/Tungsten-Nickel-Iron-Alloy-W-Ni-Fe--87-1.html), also known as tungsten-based heavy alloy, is a type of alloy made of tungsten as the matrix element (85% ~ 99% mass fraction) with the addition of Ni, Cu, Fe and other alloy elements by liquid phase sintering. The most commonly used are tungsten nickel copper and tungsten nickel iron alloy with tungsten content of 90% -97%. Tungsten nickel copper alloy is a non-magnetic alloy, while tungsten nickel iron is a magnetic alloy. W-Ni-Fe series alloys are widely used because they have better mechanical properties than W-Ni-Cu series alloys.
High-density tungsten alloy is traditionally prepared by powder metallurgy, and its sintering process is as follows:
Powder ---- Mixing --- Pressing --- Sintering --- Heat treatment --- Plastic deformation (Forging, rolling) --- Annealing-Product
Sintering
The sintering of high-density tungsten alloys mostly adopts liquid phase sintering process: normally, the sintering temperature is higher than the liquid phase temperature by 20 to 60 ℃. The sintering temperature of W-Ni-Fe alloy (https://www.edge-techind.com/Products/Refractory-Metals/T...) is 1500～1525 ℃, the density can be close to the theoretical density, the holding time is generally 60～90min.
Heat treatment
Post-sintering heat treatment includes: quenching, rapid cooling, atmospheric dehydrogenation treatment and surface hardening treatment, the purpose is to reduce the segregation of P, S and other impurities at the interface, reduce hydrogen embrittlement, improve alloy performance or meet other alloy performance requirements. Quenching and rapid cooling treatment can obtain a fine and uniform grain structure, better play the role of solid solution strengthening, and increase the strength of the alloy by 1/3 to 1/2.
Plastic deformation processing
In order to improve the mechanical properties of the alloy, various plastic deformation processes are carried out on the sintered high-density tungsten alloy. After dehydrogenation of high-density tungsten alloy by vacuum heat treatment, hydrogen embrittlement is weakened, phase boundary strength is improved, and the strength and plasticity of the alloy are greatly improved, which provides favorable conditions for high plasticization of the plastic deformation of the alloy. In the deformation strengthening process, the amount of deformation has a very important effect on the performance of the tungsten (https://www.edgetechmat.com/categories/tungsten/) alloy.
Machining
After plastic deformation, the appropriate machining method can be selected according to the drawings, such as: turning, milling, cutting, drilling, polishing, etc.