Aluminum-scandium intermediate alloy and vacuum aluminothermic reduction preparation process thereof

Abstract

The invention belongs to the technical field of metal material manufacturing, and provides an aluminum-scandium intermediate alloy and a vacuum aluminothermic reduction preparation process thereof.The preparation process comprises the steps that scandium fluoride, aluminum particles and first fused salt are mixed in a negative-pressure inert atmosphere, and first smelting is conducted to obtain first smelting alloy liquid; second fused salt and the first smelting alloy liquid are mixed for second smelting, and second smelting alloy liquid is obtained; and the second smelting alloy liquid is subjected to quenching cooling, and the aluminum-scandium intermediate alloy is obtained. The improved aluminothermic reduction method is implemented under the vacuum micro-negative pressure condition, so that introduction of impurities can be effectively reduced; the alloy liquid is severely disturbed due to micro negative pressure, so that uniform distribution of scandium is realized; the conversion rate of scandium can be increased by adding the first fused salt, the second fused salt has a purification effect, and impurities can be further separated into the slag in cooperation with strenuous movement of the alloy liquid; and rapid cooling is carried out, so that aggregation growth of an aluminum-scandium phase is avoided, and fine and dispersed precipitated phase ions are obtained.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of metal material manufacturing, and relates to an aluminum-scandium intermediate alloy and a vacuum aluminothermic reduction preparation process thereof. BACKGROUND

[0002] An intermediate alloy is a binary or multi-element alloy prepared by smelting one metal as a matrix and adding one or more other metal elements to the matrix. The aluminum intermediate alloy is used to adjust or supplement the content of specific elements in the aluminum alloy during the smelting process of the aluminum alloy, so as to realize the customized regulation of the organization structure and performance of the aluminum alloy.

[0003] The addition of a small amount of scandium in the aluminum alloy can form a large number of dispersed and coherent secondary Al3Sc phase particles, which strongly pin dislocations and subgrain boundaries, have a strong stabilizing effect on the substructure in the deformed structure, hinder dislocation movement and greatly increase the required shear stress, thereby causing alloy strengthening. Scandium in the aluminum-scandium alloy has a strong modification effect, which can refine the grains and primary compounds in the weld fusion zone, thereby reducing the tendency of weld cracking. The addition of scandium can greatly improve the strength of the aluminum alloy and reduce the tendency of weld cracking, thereby improving the weldability of the aluminum alloy. Scandium in the aluminum-scandium alloy can also increase the recrystallization temperature of the alloy and inhibit the recrystallization of the aluminum alloy, which can eliminate the recrystallized structure in the heat-affected zone of the weld and directly transition the subgrain structure of the base body to the as-cast structure of the weld. Therefore, the aluminum-scandium intermediate alloy is considered to be a new generation of high-performance aluminum alloy structural material for aerospace, ships, and weapons.

[0004] The traditional preparation methods of the aluminum-scandium alloy mainly include the doping method, the molten salt electrolysis method, the powder metallurgy method, and the aluminothermic reduction method.

[0005] The doping method, also known as the direct smelting method, is a method for preparing the aluminum-scandium intermediate alloy by directly smelting the metal Sc and Al at high temperature. Since the melting points of Sc and Al are quite different, the preparation temperature of this method is high, the alloy has a large burning loss, the recovery rate is low, and the generated Al and Sc intermetallic compound particles are large, which has a very serious composition segregation, affecting the quality of the alloy.

[0006] The molten salt electrolysis method mainly uses argon gas protection in a molten salt system, uses graphite as a cathode, and performs molten salt electrolysis at 850-1100 DEG C to prepare the aluminum-scandium alloy. This method has a high requirement for the purity of raw materials. Because common metal ions can be deposited at the cathode during the electrolysis process, the purity of the alloy is affected, the current efficiency is low (65%-80%), the corrosion of fluorine salt is serious, the electrolytic cell and electrode materials are easily corroded and invalid, the energy consumption is large, the cost is high, and the method is not environmentally friendly.

[0007] The powder metallurgy method is to obtain the aluminum-scandium intermediate alloy by mixing high-purity scandium powder and aluminum powder in a certain proportion, uniformly pressing and forming, and then performing sintering and other heat treatment processes under argon protection. This method needs expensive metal powder as raw material, has high cost, and the scandium powder and aluminum powder are easy to oxidize, have high oxygen content, affect the purity of the product, and the alloy density is difficult to reach the alloy density prepared by melting.

[0008] The aluminum-scandium alloy prepared by the aluminothermic reduction method usually adopts the direct aluminothermic reduction method of scandium fluoride. The metal thermal reduction method usually uses scandium fluoride, scandium chloride or scandium oxide as raw material, fluoride, NC1, KC1, etc. as molten salt system, and aluminum as reducing agent to prepare Al-Sc intermediate alloy, but the conversion rate of Sc is not high, generally 70% to 80%, so this method can only prepare aluminum-scandium alloy with low scandium content (usually the mass percentage of Sc is less than 2%), and the higher the scandium content of the aluminum-scandium alloy, the more serious the composition segregation, and fluorine element will also be introduced, impurities are introduced in the preparation process, and the limitation is large.

[0009] The existing aluminum-scandium intermediate alloy preparation technology faces multiple balance problems among conversion rate, purity, uniformity and cost. In particular, although the traditional aluminothermic reduction method has the advantages of simple process and low equipment investment, its low conversion rate and high impurity content seriously restrict the industrial application of high-performance aluminum-scandium alloy. It is urgent to develop a preparation method of aluminum-scandium intermediate alloy with high scandium yield, homogenization and small grain size to meet the rapid growth demand of high-end aluminum-scandium alloy materials in the field of aerospace and other fields. SUMMARY

[0010] In view of the problems in the prior art, the purpose of the present application is to provide an aluminum-scandium intermediate alloy and a vacuum aluminothermic reduction preparation process thereof. The vacuum aluminothermic reduction preparation process comprises mixing scandium fluoride, aluminum particles and a first molten salt under a negative pressure inert atmosphere, performing first melting to obtain a first molten alloy liquid; mixing a second molten salt with the first molten alloy liquid, performing second melting to obtain a second molten alloy liquid; and rapidly cooling the second molten alloy liquid to obtain an aluminum-scandium intermediate alloy. By implementing the improved aluminothermic reduction method under vacuum and micro-negative pressure conditions, the introduction of impurities can be effectively reduced; the micro-negative pressure causes the alloy liquid to be disturbed violently, achieving uniform distribution of scandium; the addition of the first molten salt can improve the conversion rate of scandium, and the second molten salt has a purifying effect, which can further separate impurities into slag in cooperation with the violent movement of the alloy liquid; and rapid cooling is beneficial to avoiding the aggregation and growth of aluminum-scandium phase to obtain fine dispersed precipitated phase ions.

[0011] To achieve this purpose, the following technical solutions are adopted in the present application:

[0012] In a first aspect, the present application provides a vacuum aluminothermic reduction preparation process of an aluminum-scandium intermediate alloy, comprising the following steps:

[0013] The scandium fluoride, aluminum particles and the first molten salt are mixed under the inert atmosphere of negative pressure to perform a first smelting to obtain a first smelted alloy liquid;

[0014] The second molten salt is mixed with the first smelted alloy liquid to perform a second smelting to obtain a second smelted alloy liquid;

[0015] The second smelted alloy liquid is rapidly cooled to obtain an aluminum scandium intermediate alloy.

[0016] The present application uses scandium fluoride and aluminum particles as raw materials under the inert atmosphere of micro-negative pressure, which is equivalent to a kind of near vacuum aluminothermic reduction process. Micro-negative pressure can make the alloy liquid disturbance relatively violent, without additional stirring equipment to realize the uniform distribution of scandium, and micro-negative pressure can effectively reduce the burning loss of graphite crucible and reduce the introduction of impurities. Further, the two times of molten salt adding means are matched, wherein the addition of the first molten salt can promote the aluminothermic reduction reaction and improve the conversion rate of scandium, and the addition of the second molten salt has a certain purification effect on the aluminum scandium alloy liquid. The violent movement of the alloy liquid can effectively separate the impurities adsorbed in the alloy liquid to the slag to reduce the introduction of inclusions, and the second molten salt can effectively prevent the volatilization of scandium and aluminum and reduce the loss during smelting. At the same time, the cooling under the rapid cooling condition is beneficial to avoid the aggregation and growth of aluminum scandium phase to obtain fine dispersed precipitated phase ions. Therefore, the scheme of the present application solves the problem that the traditional process cannot prepare a high-purity, homogeneous and small-grained aluminum scandium intermediate alloy under the premise of ensuring high conversion rate of scandium.

[0017] The following is a preferred technical solution of the present application, but not as a limitation of the technical solutions provided by the present application. Through the following technical solutions, the technical purposes and beneficial effects of the present application can be better achieved and realized.

[0018] As a preferred technical solution of the present application, the vacuum degree of the negative pressure is 5-20 Pa, for example, 5 Pa, 8 Pa, 10 Pa, 12 Pa, 14 Pa, 16 Pa, 18 Pa or 20 Pa, etc.

[0019] In the present application, the main role of negative pressure is to increase the disturbance of the molten body to make the alloy more sufficient, and also to promote the floating of the slag layer to increase the removal rate of impurities.

[0020] Preferably, the method for forming the inert atmosphere of negative pressure comprises vacuumizing first and then introducing inert gas to replace the atmosphere.

[0021] Preferably, the mass ratio of the scandium fluoride, the aluminum particles and the first molten salt is (1-4):(20-55):(1-8). For example, the mass ratio of the scandium fluoride can be 1, 1.3, 1.5, 1.8, 2, 2.3, 2.5, 2.8, 3, 3.3, 3.5, 3.8 or 4; the mass ratio of the aluminum particles can be 20, 23, 25, 28, 30, 33, 35, 38, 40, 42, 45, 48, 50, 52 or 55; and the mass ratio of the first molten salt can be 1, 2, 3, 4, 5, 6, 7 or 8.

[0022] In the present application, the first molten salt mainly plays the following roles: promoting the progress of the aluminothermic reaction, improving the reduction efficiency, and forming a eutectic compound with scandium to facilitate the generation of aluminum-scandium precipitates.

[0023] Preferably, the first molten salt comprises a first fluoride salt and a second fluoride salt.

[0024] Preferably, the first fluoride salt comprises sodium fluoride and / or calcium fluoride, and the second fluoride salt comprises sodium hexafluoroaluminate and / or aluminum fluoride.

[0025] Preferably, the mass ratio of the first fluoride salt to the second fluoride salt is (1-3):(1-3). For example, the mass ratio of the first fluoride salt can be 1, 1.3, 1.5, 1.8, 2, 2.3, 2.5, 2.8 or 3; and the mass ratio of the second fluoride salt can be 1, 1.3, 1.5, 1.8, 2, 2.3, 2.5, 2.8 or 3.

[0026] Preferably, the temperature of the first melting is 1000-1200℃, for example, 1000℃, 1020℃, 1040℃, 1060℃, 1080℃, 1100℃, 1120℃, 1140℃, 1160℃, 1180℃ or 1200℃; and the time is 10-30min, for example, 10min, 13min, 15min, 18min, 20min, 22min, 25min, 28min or 30min.

[0027] Preferably, the mass ratio of the first molten alloy to the second molten salt is 1:(0.15-0.5), for example, 1:0.15, 1:0.17, 1:0.19, 1:0.21, 1:0.23, 1:0.25, 1:0.27, 1:0.29, 1:0.31, 1:0.33, 1:0.35, 1:0.38, 1:0.4, 1:0.42, 1:0.45, 1:0.48 or 1:0.5.

[0028] Preferably, the second molten salt comprises sodium chloride and / or potassium chloride.

[0029] Preferably, the second molten salt comprises sodium chloride and potassium chloride in a mass ratio of (1-4):(2-6), for example, the proportion of sodium chloride can be 1, 1.3, 1.5, 1.8, 2, 2.3, 2.5, 2.8, 3, 3.3, 3.5, 3.8 or 4, etc.; the proportion of potassium chloride can be 2, 2.3, 2.5, 2.8, 3, 3.3, 3.5, 3.8, 4, 4.3, 4.5, 4.8, 5, 5.2, 5.5, 5.8 or 6, etc.

[0030] In the present application, the main functions of the second molten salt include effectively adsorbing impurities to purify the melt and forming a protective layer to reduce the loss of aluminum and scandium, and also can act as a diluent to reduce the viscosity of the molten salt system and accelerate the diffusion of scandium.

[0031] Preferably, the temperature of the second melting is 1000-1200℃, for example, 1000℃, 1020℃, 1040℃, 1060℃, 1080℃, 1100℃, 1120℃, 1140℃, 1160℃, 1180℃ or 1200℃, etc.; the time is 10-20min, for example, 10min, 11min, 12min, 13min, 14min, 15min, 16min, 17min, 18min, 19min or 20min, etc.

[0032] Preferably, the method of rapid cooling comprises casting cooling.

[0033] Preferably, the mold for casting cooling comprises a vertical water-cooled copper mold.

[0034] In a second aspect, the present application provides an aluminum-scandium master alloy prepared by the vacuum aluminothermic reduction process according to the first aspect.

[0035] Compared with the prior art, the present application has at least the following beneficial effects:

[0036] The present application can effectively reduce the introduction of impurities by implementing the improved aluminothermic reduction method under vacuum micro-negative pressure; the micro-negative pressure causes the alloy liquid to be disturbed violently, achieving uniform distribution of scandium; the addition of the first molten salt can improve the conversion rate of scandium, and the second molten salt has a purifying effect, which can further separate impurities into the slag in cooperation with the violent movement of the alloy liquid; rapid cooling is beneficial to avoid the aggregation and growth of aluminum-scandium phases to obtain fine and dispersed precipitated phases. Therefore, in the scheme of the present application, the conversion rate of scandium is more than 95%, and at the same time, the inclusions in the alloy are effectively reduced, and the aggregation and growth of the precipitated phases are avoided, thereby preparing an aluminum-scandium master alloy with high purity, homogenization and small grain size. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a test diagram of the microstructural characteristics of the aluminum-scandium master alloy obtained in Example 1.

[0038] Figure 2 1 is a schematic flow chart of the vacuum aluminothermic reduction preparation process of the aluminum-scandium master alloy of Example 1. DETAILED DESCRIPTION

[0039] The technical solution of the present invention is further illustrated below through specific implementation methods.

[0040] It should be apparent to those skilled in the art that the embodiments are only intended to help understand the present invention and should not be considered as specific limitations of the present invention.

[0041] Example 1

[0042] This embodiment provides a vacuum aluminothermic reduction process for preparing an aluminum-scandium master alloy. Figure 2 Shown, including

[0043] S1. 50 g of scandium fluoride, 1000 g of aluminum pellets, and a first molten salt (comprising 50 g of sodium fluoride and 100 g of aluminum fluoride) were placed in a graphite crucible of a vacuum induction furnace, and the furnace was closed; vacuuming was started using a vacuum unit. When the gas pressure in the furnace was less than 10 Pa, inert argon gas was introduced into the furnace to replace the atmosphere, achieving a slight negative pressure of 18 Pa in the furnace; then, a first smelting was performed at 1100°C for 20 min to obtain a first molten alloy liquid;

[0044] S2. A second molten salt (comprising 100 g of sodium chloride and 200 g of potassium chloride) was added through the feed port and mixed with the first molten alloy liquid, maintaining the temperature constant, and the second smelting was continued for 10 min to obtain a second molten alloy liquid;

[0045] S3. After opening the furnace cover, the second molten alloy liquid is deslagging, and then cast into a vertical water-cooled copper mold for rapid cooling. After the melt is cooled, the slag is knocked off to prepare an aluminum-scandium master alloy.

[0046] Example 2

[0047] This embodiment provides a vacuum aluminothermic reduction process for preparing an aluminum-scandium master alloy, comprising:

[0048] S1. Put 100 g of scandium fluoride, 2000 g of aluminum particles, and a first molten salt (including 100 g of sodium fluoride and 200 g of aluminum fluoride) into a graphite crucible of a vacuum induction furnace, close the furnace body; start vacuumizing by using a vacuum unit, after the gas pressure in the furnace is less than 10 Pa, inert gas is introduced into the furnace, the atmosphere is replaced, so that the furnace realizes a micro negative pressure of 15 Pa; then first smelting is carried out at 1150 DEG C for 30 min, and a first smelting alloy liquid is obtained;

[0049] S2. The second molten salt (including 200 g of sodium chloride and 400 g of potassium chloride) is added through the feeding port to mix with the first smelting alloy liquid, the temperature is kept unchanged, and second smelting is continued for 10 min, and a second smelting alloy liquid is obtained.

[0050] S3. After opening the furnace cover, the second smelting alloy liquid is subjected to slagging operation, and then is poured into a vertical water-cooled copper mold for rapid cooling, and after the molten body is cooled, the slag is knocked off, and an aluminum scandium intermediate alloy is prepared.

[0051] Example 3

[0052] The embodiment provides a vacuum aluminothermic reduction preparation process of an aluminum scandium intermediate alloy, the micro negative pressure vacuum degree of step S1 is adjusted to 5 Pa, and other conditions are completely same as those in example 1.

[0053] Example 4

[0054] The embodiment provides a vacuum aluminothermic reduction preparation process of an aluminum scandium intermediate alloy, the micro negative pressure vacuum degree of step S1 is adjusted to 20 Pa, and other conditions are completely same as those in example 1.

[0055] Example 5

[0056] The embodiment provides a vacuum aluminothermic reduction preparation process of an aluminum scandium intermediate alloy, the micro negative pressure vacuum degree of step S1 is adjusted to 30 Pa, and other conditions are completely same as those in example 1.

[0057] Example 6

[0058] The embodiment provides a vacuum aluminothermic reduction preparation process of an aluminum scandium intermediate alloy, the ratio of sodium chloride to potassium chloride of the second molten salt of step S2 is kept unchanged, the total mass is adjusted to 120 g, so that the mass ratio of the first smelting alloy liquid to the second molten salt is adjusted to 1:0.1, and other conditions are completely same as those in example 1.

[0059] Example 7

[0060] The embodiment provides a vacuum aluminothermic reduction preparation process of an aluminum-scandium master alloy, the second molten salt in step S2 is kept unchanged in terms of the proportion of sodium chloride and potassium chloride, the total mass is adjusted from 300g to 180g, so that the mass ratio of the first molten alloy liquid to the second molten salt is adjusted from 1:0.25 to 1:0.15, and the conditions are completely same with those in example 1 except the above.

[0061] Example 8

[0062] The embodiment provides a vacuum aluminothermic reduction preparation process of an aluminum-scandium master alloy, the second molten salt in step S2 is kept unchanged in terms of the proportion of sodium chloride and potassium chloride, the total mass is adjusted from 300g to 420g, so that the mass ratio of the first molten alloy liquid to the second molten salt is adjusted from 1:0.25 to 1:0.35, and the conditions are completely same with those in example 1 except the above.

[0063] Example 9

[0064] The embodiment provides a vacuum aluminothermic reduction preparation process of an aluminum-scandium master alloy, the second molten salt in step S2 is kept unchanged in terms of the proportion of sodium chloride and potassium chloride, the total mass is adjusted from 300g to 480g, so that the mass ratio of the first molten alloy liquid to the second molten salt is adjusted from 1:0.25 to 1:0.4, and the conditions are completely same with those in example 1 except the above.

[0065] Comparative Example 1

[0066] The comparative example provides a vacuum aluminothermic reduction preparation process of an aluminum-scandium master alloy, the first molten salt and the second molten salt are combined and only subjected to one smelting, and the specific process comprises the following steps.

[0067] 50g scandium fluoride, 1000g aluminum particles, the first molten salt (containing 50g sodium fluoride, 100g aluminum fluoride, 100g sodium chloride and 200g potassium chloride) are put into a graphite crucible of a vacuum induction furnace, and the furnace body is closed; a vacuum machine set is used to start vacuumizing, inert gas is introduced into the furnace after the gas pressure in the furnace is less than 10Pa, atmosphere replacement is carried out, so that the furnace realizes micro negative pressure of 18Pa; then the first smelting is carried out at 1100 DEG C for 30min, and the first molten alloy liquid is obtained.

[0068] After the furnace cover is opened, the second molten alloy liquid is subjected to slagging operation, then is cast into a vertical water-cooled copper mold for rapid cooling, and the slag is knocked off after the molten body is cooled, so that the aluminum-scandium master alloy is prepared.

[0069] Characterization and testing:

[0070] Ⅰ. Figure 1 It is a microstructure feature test diagram of the aluminum-scandium master alloy obtained in example 1, and it can be seen from the diagram that the particle size of the aluminum-scandium precipitated phase is small and is less than 15um.

[0071] II. In Example 1 and Example 2, sampling was carried out, component tests were carried out, and the results are shown in Table 1.

[0072] Table 1

[0073]

[0074] As can be seen from Table 1, the average scandium content of the aluminum scandium intermediate alloy obtained in Example 1 is 2.15%, the range is 0.03%, and the yield is 95.30%; the average scandium content of the aluminum scandium intermediate alloy obtained in Example 2 is 2.18%, the range is 0.05%, and the yield is 96.63%, and the results of other examples and comparative examples are listed in Table 2.

[0075] Table 2

[0076] Group Average Sc content (wt%) Range of average Sc content (%) Yield (%) Example 1 2.15 0.03 95.30 Example 2 2.18 0.05 96.63 Example 3 2.15 0.05 95.28 Example 4 2.10 0.03 94.11 Example 5 2.02 0.02 84.77 Example 6 1.94 0.07 86.12 Example 7 2.08 0.05 92.34 Example 8 2.14 0.04 95.42 Example 9 2.13 0.05 95.49 Comparative Example 1 2.09 0.05 92.27

[0077] As can be seen from Table 2: appropriate negative pressure of the system can make the reaction more sufficient, with the increase of the negative pressure, the scandium conversion rate is higher, and at the same time, the aluminum scandium intermediate alloy obtained is more uniform, but too large negative pressure will make the reaction particularly violent, accelerate the volatilization of scandium, and even make the melt splash, so that the scandium yield decreases sharply; the addition of the second molten salt is beneficial to the conversion of scandium, but too much molten salt will increase the cost and produce more slag subsequently; the addition of the second molten salt too early will cause serious burning loss, so that the consumption is larger.

[0078] In summary, by using the improved aluminothermic reduction method under the condition of vacuum micro negative pressure, the introduction of impurities can be effectively reduced; the micro negative pressure causes the alloy liquid to be disturbed violently, so that the scandium is uniformly distributed; the addition of the first molten salt can improve the conversion rate of scandium, and the second molten salt has a purifying effect, which can further separate the impurities into slag in cooperation with the violent movement of the alloy liquid; rapid cooling is carried out, which is beneficial to avoiding the aggregation and growth of the aluminum scandium phase, so as to obtain fine and dispersed precipitated phase ions. Therefore, in the scheme of the present application, the conversion rate of scandium is more than 95%, the inclusions in the alloy are effectively reduced, and the aggregation and growth of the precipitated phase are avoided, so that a high-purity, homogeneous and small-grained aluminum scandium intermediate alloy is prepared.

[0079] The preferred embodiments of the present application are described in detail above, but the present application is not limited to the specific details in the above-described embodiments, and various simple modifications can be made to the technical solutions of the present application within the technical concept of the present application, and these simple modifications all belong to the protection scope of the present application.

[0080] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any appropriate manner without contradiction, and in order to avoid unnecessary repetition, the present application will not describe various possible combinations again.

[0081] Furthermore, the various embodiments can also be combined, if not in contradiction, as long as they do not deviate from the spirit of the present application, which should be considered as disclosed.

Claims

1. A vacuum aluminothermic reduction process for preparing an aluminum-scandium master alloy, characterized in that: The steps include: In an inert atmosphere with negative pressure, scanning fluoride, aluminum particles and a first molten salt are mixed and first smelted to obtain a first molten alloy liquid; mixing a second molten salt with the first molten alloy liquid, and performing a second smelting to obtain a second molten alloy liquid; The second molten alloy liquid is rapidly cooled to obtain an aluminum-scandium master alloy.

2. The vacuum aluminothermic reduction process for preparing an aluminum-scandium master alloy according to claim 1, characterized in that: The vacuum degree of the negative pressure is 5 to 20 Pa; Preferably, the method for forming the negative pressure inert atmosphere includes first evacuating the atmosphere and then introducing an inert gas to replace the atmosphere.

3. The vacuum aluminothermic reduction process for preparing an aluminum-scandium master alloy according to claim 1 or 2, characterized in that: The mass ratio of the scandium fluoride, the aluminum particles and the first molten salt is (1-4):(20-55):(1-8).

4. The vacuum aluminothermic reduction process for preparing an aluminum-scandium master alloy according to any one of claims 1 to 3, characterized in that: The first molten salt includes a fluoride salt; Preferably, the fluoride salt includes a first fluoride salt and a second fluoride salt; the first fluoride salt includes sodium fluoride and / or calcium fluoride; the second fluoride salt includes sodium hexafluoroaluminate and / or aluminum fluoride; Preferably, the mass ratio of the first fluoride salt to the second fluoride salt is (1-3):(1-3).

5. The vacuum aluminothermic reduction process for preparing an aluminum-scandium master alloy according to any one of claims 1 to 4, characterized in that: The temperature of the first smelting is 1000-1200° C., and the time is 10-30 minutes.

6. The vacuum aluminothermic reduction process for preparing an aluminum-scandium master alloy according to any one of claims 1 to 5, characterized in that: The mass ratio of the first molten alloy liquid to the second molten salt is 1:(0.15-0.5).

7. The vacuum aluminothermic reduction process for preparing an aluminum-scandium master alloy according to any one of claims 1 to 6, characterized in that: The second molten salt includes sodium chloride and / or potassium chloride; Preferably, the second molten salt comprises sodium chloride and potassium chloride in a mass ratio of (1-4):(2-6).

8. The vacuum aluminothermic reduction process for preparing an aluminum-scandium master alloy according to any one of claims 1 to 7, characterized in that: The second smelting is carried out at a temperature of 1000-1200° C. and for a time of 10-20 minutes.

9. The vacuum aluminothermic reduction process for preparing an aluminum-scandium master alloy according to any one of claims 1 to 8, characterized in that: The quench cooling method includes casting cooling; Preferably, the casting and cooling mold comprises a vertical water-cooled copper mold.

10. An aluminum-scandium master alloy, characterized in that: Obtained according to the vacuum aluminothermic reduction preparation process according to any one of claims 1 to 9.

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