High density tungsten alloys High density tungsten alloys High density tungsten alloys are alloys based on tungsten (W) and added with other alloying elements. Also known as heavy tungsten alloy. In 1935, the liquid phase sintering method was used for the first time to produce tungsten-nickel-copper (W-Ni-Cu) alloy. This alloy gained widespread use in the 1960s. After the 1970s, high-density tungsten alloy was successfully used as core material for armor-piercing projectiles and became an important engineering material in industrial production. High-density tungsten alloy generally contains 85 to 98% tungsten. The main alloying elements are nickel (Ni), iron (Fe), and copper (Cu). Usually divided into two broad categories. ① Tungsten-nickel-copper alloy: Ni and Cu form a solid solution (or matrix phase). Cu can reduce the solubility of W in the solid solution and avoid the formation of tungsten-nickel (Y-Ni) intermetallic compounds; it can also lower the melting point of the solid solution to ensure that the W phase is better infiltrated by the matrix phase. The alloy composition Ni:Cu is mostly 3 to 2. ②Tungsten-nickel-iron alloy: Ni:Fe in the alloy composition is 7-3. The mechanical properties can be improved after vacuum heat treatment, and plastic addition can be performed. Compared with the W-Ni-Cu system, the strength of the alloy is significantly improved. In addition, according to the use requirements, W-Ni-Mo, W-Ni-Cr and W-Ni-Co series alloys have also been developed. High-density tungsten alloys are usually made by rod powder, pressing and sintering. During the sintering process, the sintering temperature is higher than the melting point of the matrix phase in the alloy to produce a liquid phase, which accelerates the sintering process of the alloy and makes the alloy rapidly densified and close to the theoretical level. density. In order to further improve the properties of the alloy, heat treatment and plastic processing are also used. The rotary forging process is commonly used in industry to improve the alloy structure. High-density tungsten alloy has high density, high strength, good plasticity and cutting performance, good electrical and thermal conductivity, low expansion coefficient, good corrosion resistance and oxidation resistance, and excellent radiation absorption ability , good weldability. Mainly used as gyroscope rotor materials, balance weight materials, armor-piercing projectile core materials, kernel mold fixture materials, shielding materials and instrumentation materials. (