Preparation can adopt steel ingot billet forming or cold isostatic pressing into a shape alloy, compact in hydrogen hanging furnace or the intermediate frequency furnace or through the compact hydrogen resistance furnace burning into relative density of 85% ~ 85% density of spindle, also have use ingot hot isostatic pressing legal system. Sintered ingots are made of different kinds of processing materials, such as rod, wire, sheet, foil and strip, etc. Have good processability of rhenium tungsten alloy composition is W - (18 ~ 26) Re, alloy process recommended best forging temperature is 1500 ℃ and the annealing temperature is 1600 ~ 1800 ℃. Re content of >26% alloy, the allowable phase content is limited. Although this second phase precipitation leads to material reinforcement, its processing performance is still very good. Re content < 18% alloy can be processed smoothly, but the initial processing temperature is higher.
The w-re alloy has a long, elongated fibrous tissue. After different heat treatment system, the organization has significant changes, such as W - 3 re wire a recrystallization temperature of 1300 ~ 1900 ℃, the secondary recrystallization temperature of 2500 ℃, W - 25 re wire a recrystallization temperature of 1000 ~ 1500 ℃, the secondary recrystallization temperature of 1800 ℃. A recrystallization, the wire inside the serrated border, known as the edge of the grain boundary recrystallization, but its microstructure is still the fibrous tissue before annealing, such as the right of the shown in (a) (b). The right atlas (c) and (d) are the metallographic structures of a recrystallization, which can be seen that the tissue is still fibrous, but the fibers are shorter. In the second recrystallization, the internal tissue of the silk material gradually formed from the fibrous aggregates into a thick secondary recrystallization structure.
Both tungsten and rhenium are high melting point metals, which are widely used in high temperature fields. But they also have shortcomings, pure tungsten brittleness, recrystallization temperature is very low; Pure rhenium is poorly processed and expensive. The limits of their application are greatly limited. Made components with the rhenium tungsten rhenium tungsten alloy, the alloy overcomes the drawback of pure tungsten and rhenium, has many excellent properties, such as high melting point, high strength, high hardness, high plasticity, high resistivity, high thermoelectric potential value of the recrystallization temperature, high, low vapor pressure, low electron work function and low plastic a brittle transition temperature, etc., at the same time they also have excellent resistance to "water cycle" response performance, the price is lower than the pure rhenium 75 ~ 95%.
So the tungsten-rhenium alloy in modern electronic technology, thermal control, nuclear technology and space technology, temperature field, instruments and meters, electrical appliances and other sophisticated science and technology department has been widely used. Especially the tungsten-rhenium alloy wire matching thermocouple, has the very high thermoelectric potential and sensitivity, and temperature measuring range, fast response, good corrosion resistance, is temperature measurement in the field of good thermal sensing materials. It is an inevitable trend to replace the platinum-rhodium thermocouple with the tungsten rhenium thermocouple.
