A few days ago, the aluminum-lithium alloy chassis shell developed by Jiangsu Yuefeng Aluminum Technology Co., Ltd. was successfully delivered. The chassis shell is used in a certain type of domestic fighter, which is made of aluminum-lithium alloy forgings by numerical control machining and surface anti-corrosion treatment, and reduces weight by 11% compared with the original aluminum alloy shell. it has an "immediate" weight reduction effect on the basis of ensuring the original load-bearing and anti-corrosion requirements.
At present, the urgency of weight loss for aviation and aerospace vehicles has entered the era of "gram calculation". Aircraft designers have racked their brains for weight loss, from structural design to the replacement of raw materials. Weight loss has become an "eternal" goal in the development of aircraft. As a lightweight and high-strength metal structural material, Al-Li alloy has a very broad application prospect in the aviation and aerospace fields. for every 1% lithium added to the alloy, the density is reduced by 3% and the elastic modulus is increased by 6%. Using Al-Li alloy instead of conventional high-strength aluminum alloy can reduce its structural weight by 5% to 15% and increase its stiffness by 15% to 20%. At the same time, Al-Li alloy has strong corrosion resistance and can pass GJB96h and 192h acid salt spray test. Under the condition of ensuring the original operating load, directly using lightweight and high-strength Al-Li alloy to replace the original aluminum alloy for weight reduction will effectively reduce the structural weight of the aircraft and improve the effective loading quantity and maneuverability of the strategic aircraft. meet its ultra-high-altitude, ultra-high-speed, high-precision and multi-functional development requirements, and then meet the strategic needs of weapons and equipment in modern warfare. It is reported that in order to achieve weight loss, some aircraft at home and abroad have used magnesium alloy which has weight advantages compared with aluminum alloy, but the fatal "easy corrosion" and "flammable" defects of magnesium alloy hinder its application in aircraft. can not meet the all-weather, all-regional strategic combat needs of modern war aircraft.
Because lithium is very active, smelting Al-Li alloy under atmospheric conditions is easy to oxidize to form slagging and absorb hydrogen, which seriously affects the properties and quality of the alloy. At present, there are three methods to produce Al-Li alloy in the world: (1) vacuum melting and casting; (2) gas protection melting + negative pressure hydrogen pumping static + semi-continuous casting; (3) gas protection melting + spray deposition casting. For this reason, Yuefeng Aluminum Technology Co., Ltd. set up Al-Li alloy R & D department and solved the problems of easy hydrogen absorption, oxidation slagging, composition segregation and easy shrinkage of Al-Li alloy by vacuum casting with the help of national R & D platform. 1420, 2195 and other brands of Al-Li alloys have been developed, which can provide plate, strip foil, tube bar wire, forgings and other products in batches, and parts can be provided according to customer drawings. At the same time, for the pre-research model of Al-Li alloy, the company has the full process development ability from design drawings to parts delivery (melting and casting, extrusion, processing forming, heat treatment, machining, surface, inspection).
