Method for preparing aluminum-scandium alloy with high scandium content

Abstract

The invention discloses a method for preparing an aluminum-scandium alloy with high scandium content. The method comprises the steps that metal scandium and metal aluminum are weighed according to thescandium content in the aluminum-scandium alloy needing to be prepared; the obtained materials are added into a medium-frequency induction melting furnace, continuously vacuumizing is carried out, and then heating is carried out to 1200-1600 DEG C to melt the metal scandium and the metal aluminum; after complete melting is achieved, alloy liquid is obtained, and heat preservation is carried out for 20-40 min; and high-purity argon is introduced in, the alloy liquid subjected to heat preservation is poured into a water-cooled copper die, circulating water is cooled to 1-15 DEG C by adopting amold circulating water refrigerating system, the cooled circulating water is introduced into the water-cooled copper die to circularly cool the alloy liquid, and cooling and solidifying of the alloy liquid can be completed within 3-8 seconds to obtain an aluminum-scandium alloy cast ingot with scandium content of 5%-99%. According to the method, rapid cooling can be achieved within 3-8 s, the aluminum-scandium alloy with high scandium content which is high in purity, high in compactness, low in segregation, uniform in component and low in cost can be prepared, and the requirement of the current market for the aluminum-scandium alloy with high scandium content is met.

Description

technical field [0001] The invention relates to the technical field of preparation of aluminum-scandium alloys, in particular to a method for preparing aluminum-scandium alloys with high scandium content. Background technique [0002] Metal scandium is currently the most effective additive element to optimize the performance of aluminum alloys. A trace amount of scandium has a significant effect on refining alloy grains and inhibiting recrystallization. Aluminum-scandium alloy has the characteristics of high strength, low density, corrosion resistance, high temperature resistance, and good weldability. It is widely used in high-tech fields such as aerospace, nuclear missiles, high-speed trains, and sports equipment, especially in the electronic information technology industry. The aluminum-scandium alloy target with high scandium content can increase electron migration and stress displacement several times while maintaining the same electrical conductivity, and meet the requ...

AI Technical Summary

Problems solved by technology

[0004] The method of blending is to directly add metal scandium to molten aluminum, and then cast aluminum scandium alloy after stirring. Due to the active chemical properties of metal scandium, the melting point of metal aluminum is quite different, so the higher the content of scandium, the more difficult it is to smelt the alloy; Direct furnace cooling and solidification of the alloy can easily lead to coarse grains of the alloy, serious composition segregation, low density, and poor mechanical properties, which are not conducive to subsequent deformation processing

[0005] The aluminothermic reduction method uses scandium-containing compounds as raw materials, metal aluminum as the reducing agent, and the scandium-containing raw materials are reduced to metal scandium in the aluminum melt at high temperature, and the formed metal scandium diffuses into the aluminum melt or forms aluminum scandium compounds with aluminum , the prior art discloses that scandium oxide is used as a raw material, molten aluminum is used as a reducing agent, potassium chloride, sodium fluoride, additives and other additives are added, and scandium oxide is reduced to metal scandium at high temperature, which enters the aluminum liquid to form The method of the master alloy has the following problems: fluorine element will be introduced into the product, the environmental pollution is serious, and it is mostly used to prepare aluminum-scandium alloy with low scandium content, etc.

[0006] The molten salt electrolysis method is based on the molten salt electrolysis system (Na 3 AlF 6 -KCl-NaCl-ScF 3 or ScCl 3 -KCl-NaCl or Na 3 AlF 6 -LiF-Sc 2 o 3 etc.) into argon protection, at 850-1100 ° C, the graphite cathode is electrolyzed with molten salt to prepare aluminum-scandium alloy, the motor and electrolytic cell in this process are prone to corrosion, and the power consumption is large, resulting in high cost and not environmentally friendly

[0007] The powder metallurgy method is to mix high-purity metal aluminum powder and high-purity metal scandium powder according to a certain proportion, press them into shape, and sinter them in a protective atmosphere to prepare aluminum-scandium master alloys. Currently, there are technologies that can prepare aluminum-scandium master alloys with a scandium content of 0.1%~ 15%, 16%-50%, 55%-70% aluminum-scandium alloys, but metal scandium powder and aluminum powder are easy to oxidize, resulting in high oxygen content in the alloy, affecting product purity, and low alloy density

[0008] In addition, the Chinese application CN110904364A discloses a method for preparing an aluminum alloy target. This method can only prepare an aluminum-scandium alloy target with a scandium content of 5% to 20%. The alloy liquid is directly cooled and formed in a water-cooled copper mold. When the content of scandium increases, the melting point of the alloy increases, or the input of raw materials is increased for the preparation of large-size aluminum-scandium alloy targets, the preparation method has limited refrigeration capacity and cannot achieve a faster cooling rate, resulting in segregation of alloy components and reduction in density, etc. problem, can not meet the needs of use

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