Rhenium is a rare metal element, which is located at the 75th position of the periodic table and adjacent to tungsten (74). It is a well-known characteristic that its melting point is 3180 ° C and it is the second refractory metal.it is tungsten with a melting point of 3410 ° C.
rhenium was not discovered recently, nor was it first discovered in China. In 1925, the German chemist Nordak discovered this element in niobium-manganese ore by spectrometry and named it rhine as the name of the Rhine river. Because of the lack of resources and high prices, it is said that there are only over 2,500 tons in the world. The main producing countries, such as Chile and Poland, have been bought out by the United States. China has about 200 tons of reserves.
In the field of alloys, the use of rhenium is no secret. The metal elements that are most combined with rhenium are tungsten and molybdenum. Rhenium can simultaneously improve the strength and plasticity of tungsten and molybdenum. People call this phenomenon the "rhenium effect". Adding a small amount of 3% to 5% of rhenium can increase the recrystallization starting temperature of tungsten by 300 ° C to 500 ° C, and improve its high temperature strength and plasticity. Or you can describe it this way, the rare earth is often referred to as monosodium glutamate in modern industry, and the element rhenium is monosodium glutamate in tungsten and molybdenum industry. With it, tungsten molybdenum metal is active and fragrant; without it, tungsten molybdenum metal is simply "tasteless".
Tungsten-rhenium alloy has a series of excellent properties, such as high melting point, high strength, high hardness, high plasticity, high recrystallization temperature, high resistivity, low vapor pressure, low electron work function, and low plastic brittle transition temperature. One of the best comprehensive properties of tungsten alloys, it can be processed into plates, sheets, wires, wires, rods, high temperature structural parts (nozzles, nozzles, heat shields, etc.), elastic components and electronics for aerospace and aviation Components and other important devices are indispensable and important elements in the aerospace field. Copyright China Tungsten Online
As the heart of an aircraft, an aero engine is a highly complex and sophisticated thermal machine, known as the "crown of modern industrial technology". The crown jewel is the turbine blade of an aero engine, which is the core component of the engine. Performance, especially the ability to withstand high and low temperatures, is an important indicator of a country's aviation industry level. For many years, the stagnation of our aerospace engine development is not due to insufficient design capabilities. On the contrary, the reverse engineering capabilities of Chinese scientists are very strong. The main problem is that the material science is backward and it is difficult to find out the alloy material formula of foreign engines. Turbine blades are the engine parts that have the most manufacturing processes, the longest cycles, the lowest qualification rates, and the strictest foreign blockades and monopolies among all the parts of aero-engines. At present, our scientists can only cross the river by feeling the stones.
With the installation of next-generation fighters such as the F35, SU35, J20, and other major powers in China, the United States, and Russia, twin-cylinder engines have become standard for fighter engines, and the requirements for aerospace engines have become higher and higher. The main material of aerospace engine blades is nickel-based superalloys. Early Chinese engine blades had short lifespans, not just material problems, but single crystal process problems. In 2009, technical expert Zhou Yizhang returned from the University of Birmingham in the United Kingdom and was selected into the "Hundred Talents Program" of the Chinese Academy of Sciences. He is engaged in research on superalloys at the Institute of Metal Research of the Chinese Academy of Sciences. Under its leadership, the scientific research team changed the past situation of accumulation of experience and trial and error. Instead, it developed a variety of single-crystal superalloy blades through advanced theory and practice, solving a variety of single-crystal blades from scratch. problem. Today, China's single crystal blade technology has developed to the third generation, and China is also one of the five countries in the world that can research and manufacture aerospace engines. The pace is large, but there is still a gap. Copyright China Tungsten Online
It is undeniable that rhenium has an extremely important role in lifting engine blades. The matrix of the single crystal superalloy material is nickel, which contains rare precious metals such as rhenium, ruthenium, tantalum, tungsten, molybdenum, and cobalt. Although tungsten is the most high temperature resistant material, it has always been one of the main metal elements of various parts of the aerospace engine, but the influence of the blade is not prominent. Tungsten will oxidize at a certain high temperature, but rhenium will not, so It has stronger creep resistance than tungsten. With the strengthening of plutonium, the engine blades can be used in high-temperature working environments without fear of rapid cooling and violent heating, and work under conditions of strong mechanical shock and vibration for a long time without deformation and cracking. This is to improve the life of engine blade And performance-critical parameters.
Composite material technology has always been the top priority of high-end military science and technology research in various countries. Rhenium, ruthenium, tantalum, tungsten, molybdenum, and cobalt are all important metal elements in engine blades. Whoever lacks aerospace engine blades can't make a good turn. The blades of Taihang engines that are formally equipped with J-10B and J-11 in China are added with 3-6% plutonium. The overhaul interval has been increased from 300 hours to 750 hours, and the service life has reached more than 2000 hours! If the latest single crystal blade technology can be applied to the WS15 engine, the Chinese J-20 fighter will gain a more powerful "Chinese heart".
It should be noted that rhenium is one of the world`s least scarce strategic minerals. China`s reserves are only over 200 tons, which are mainly found in molybdenum ore, which is very different from China ’s first tungsten reserves in the world. Although rhenium is a good thing, but more than 200 tons is not enough for the aerospace industry in China, and the price is extremely expensive. At present, most of the world's ore mines have been occupied by the United States. It is conceivable that if western countries blockade our country like the arms embargo and technical barriers in the future, how should China`s aerospace industry respond? Therefore, we should also plan ahead, while establishing strategic resource reserves, in the research of superalloys Reducing the dependence on thorium, a weak resource, may return to the research track of tungsten and other refractory metal alloys.