Tungsten-rhenium alloy is a solid solution reinforced alloy consisting of tungsten and rhenium.The commonly used rhenium contents (mass fraction, %) in alloys are 3,5,10,25 and 26. It can be divided into low content W-Re alloy (Re≤5%) and high content W-Re alloy (Re≥15%). When the content of Re in the alloy exceeds 26%, the brittle phase will precipitate in W-Re alloy.
According to the preparation method, strengthening method and selection of tungsten-based raw materials, tungsten-rhenium alloys are classified as shown in the figure on the right.
The main processing materials of tungsten-rhenium alloy are wire and sheet. Silk material accounts for the vast majority. Mainly used as high temperature structural material.
Tungsten-rhenium alloys have better mechanical properties and ductility than pure tungsten, as well as higher electrical resistivity, so they have better workability and weldability. The tungsten-rhenium alloy containing 3% rhenium can be used as the core metal of tube filament, gate wire and direct-heating cathode. Thorium containing tungsten-rhenium alloy, namely thorium tungsten-rhenium alloy, used as the direct thermal cathode of large emission tubes, has better performance than thorium tungsten-cathode and is not easy to deform at high temperature.
Tungsten-rhenium alloy waste is mainly tungsten-rhenium alloy, also including molybdenum-rhenium alloy. Methods for recovery of rhenium from waste tungsten-rhenium alloy: aerobic chemotaxation and nitre fusion decomposition - ion exchange method. Make tungsten rhenium alloy has powder metallurgy method and smelting method two kinds, its production.
The process is shown on the right. In the actual production of powder metallurgy method is dominant. High quality alloy billets with the best uniformity and consistency can be obtained by isostatic pressing and medium frequency induction heating sintering.Sintered ingots are made into different types of processed materials by different processing methods (rotary forging, rolling, drawing, etc.).
Bar, wire, sheet, foil and strip, etc. The tungsten-rhenium alloys with good machinability are composed of W-(18 ~ 26)Re, and the recommended best forging temperature is 1500℃ and annealing temperature is 1600 ~ 1800℃. In the alloy with 26% Re content of >, the allowable phase content is limited. Although the precipitation of this second phase results in the strengthening of the material, its processability is still very good. The alloy with Re content less than 18% can be processed smoothly, but the initial processing temperature is higher.
