According to different uses,
tungsten alloy is divided into hard alloy, high density alloy, metal sweat material, contact material, electronic and electric light source material.
Doping
tungsten wire is to add about 1% of silicon, aluminum and potassium oxide in tungsten powder, in the vertical melting (self-resistance sintering) process, the additive potassium oxide volatilization, in the material internal pores, pores after processing along the axial elongation; After annealing, the elongated pores form diffused lines of bubbles parallel to the wire axis, commonly known as potassium bubbles. Potassium bubbles can prevent the transverse growth of tungsten grains, improve the anti-sag property of tungsten at high temperature, and improve the plasticity at room temperature after recrystallization, which is beneficial to wire wrapping and transportation and storage. China doped tungsten wire has three grades of WAl1, WAl2 and WAl3 according to the creep value of high temperature. In The W-THO2 alloy, due to the addition of an appropriate amount of THO2 particles with good thermal stability and dispersion, the electron escape work can be reduced and the growth of tungsten grains can be inhibited, so that the material has a high recrystallization temperature, excellent high-temperature strength and creep resistance. Tungsten and thorium alloys are not only widely used thermal electron emission materials, but also excellent electrode materials.
In tungsten rhenium alloy, the addition of Rhenium can not only improve the material strength, increase the recrystallization temperature of the alloy about 200 ~ 400℃, make the secondary recrystallization have good plasticity and slow grain growth, but also significantly reduce the plastic-brittle transition temperature. The addition of more than 30% rhenium can damage the machining properties of the alloy. Tungsten-rhenium alloy also has a high thermoelectric potential, which is linearly related to temperature at 2200℃.Tungsten Rhenium thermocouple measuring temperature up to 3000℃, is an excellent high temperature thermocouple material.
