阅读说明：本技术 一种铝锂合金中钪元素的添加方法 (Method for adding scandium element in aluminum-lithium alloy ) 是由 杨东辰 张亮 吴国华 刘文才 丁文江 于 2021-06-23 设计创作，主要内容包括：本发明提供了一种铝锂合金中钪元素的添加方法。通过添加氯化锂(LiCl)、氯化钾(KCl)、氟化锂(LiF)以及三氟化钪(ScF-3)所形成的混合熔融盐,通过与熔体发生置换反应的方式在铝锂合金中添加钪元素。本发明优化了熔盐各成分的比例,所制备的混合熔盐具有适宜的熔点,在较低的熔炼温度下即可完成钪的合金化。在加入铝锂合金熔体之后,该混合熔盐能够充分与铝锂合金熔体接触,提高了钪的收得率。同时在使用过程中,氯化锂、氯化钾、氟化锂等兼具精炼和保护熔体的作用,可降低氧化夹杂。此外,本发明提供的方法操作简单、易于实现。(The invention provides a method for adding scandium in an aluminum-lithium alloy. By adding lithium chloride (LiCl), potassium chloride (KCl), lithium fluoride (LiF) and scandium trifluoride (ScF) 3 ) The resulting mixed molten salt is added with scandium element to the aluminum-lithium alloy by a substitution reaction with the melt. The invention optimizes the proportion of each component of the molten salt, and the prepared mixed molten salt has a proper melting point and can complete scandium alloying at a lower melting temperature. After the aluminum lithium alloy melt is added, the mixed molten salt can be fully contacted with the aluminum lithium alloy melt, and the scandium yield is improved. Meanwhile, in the using process, lithium chloride, potassium chloride, lithium fluoride and the like have the functions of refining and protecting the melt, and the oxide inclusion can be reduced. In addition, the method provided by the invention is simple to operate and easy to realize.)

1. A method for adding scandium in an aluminum-lithium alloy, characterized by adding a mixed molten salt containing lithium chloride, potassium chloride, lithium fluoride and scandium trifluoride to the aluminum-lithium alloy, and causing a substitution reaction with the melt, thereby adding scandium to the aluminum-lithium alloy.

2. The method for adding scandium contained in the aluminum-lithium alloy according to claim 1, wherein a weight ratio of lithium chloride, potassium chloride, lithium fluoride and scandium trifluoride in the mixed molten salt is 6 to 9: 6-9: 3-5: 1 to 3.

3. The method of adding scandium contained in the aluminum-lithium alloy according to claim 1, wherein the mixed molten salt is obtained by:

mixing lithium chloride, potassium chloride, lithium fluoride and scandium trifluoride to obtain a mixture; the obtained mixture was dried, and then the dried mixture was heated and stirred in a heat-retaining state to obtain a mixed molten salt.

4. The method of adding scandium contained in the aluminum-lithium alloy according to claim 3, wherein the lithium chloride, the potassium chloride, the lithium fluoride, and the scandium trifluoride before mixing are in a powdery form.

5. The method for adding scandium contained in an aluminum-lithium alloy according to claim 3, wherein a temperature of said drying is 170 ℃ to 210 ℃; the drying time is 40-60 min.

6. The method for adding scandium contained in the aluminum-lithium alloy according to claim 3, wherein the heating temperature is 750 to 850 ℃ and the holding time is 20 to 40 min.

7. The method of claim 1, wherein the temperature of the molten salt mixture added to the alloy is 720 to 750 ℃; the reaction time is 30-60 min.

8. The method of claim 1, wherein the molten salt is mixed with the melt and the mixture is stirred for 5 to 10 minutes at 5 to 10 minute intervals.

9. The method of claim 1, wherein the vessel used for mixing the molten salt and reacting with the molten metal is made of graphite.

10. The method of claim 1, wherein the molten salt mixture is added in an amount of 2 to 5 wt.% based on the aluminum-lithium alloy.

Technical Field

The invention belongs to the field of metal materials and metallurgy, and particularly relates to a method for adding scandium in an aluminum-lithium alloy, which has the advantages of high actual yield, low molten salt adding temperature, uniform components and no coarse Al₃Sc phase, simple equipment requirement, low smelting temperature and convenient addition method of scandium element in aluminum-lithium alloy for industrial production。

Background

In recent years, aluminum lithium alloys have attracted much attention on the way of light weight and high strength of metal materials. The density can be reduced by 3% and the elastic modulus can be increased by 6% when 1% of lithium element is added into the aluminum alloy, and the strength of the aluminum alloy can be comparable to that of the traditional high-strength aluminum alloy. Through decades of development, the aluminum lithium alloy has been successfully applied to high precision fields such as aerospace, military equipment and the like.

Scandium metal is a transition metal, and therefore has both characteristics of a rare earth element and a transition element. The addition of trace scandium in the aluminum-lithium alloy can obviously affect the structure and performance of the alloy, and greatly improve the strength, corrosion resistance, welding performance and the like. Scandium is a powerful grain refiner and an effective recrystallization inhibitor for aluminum-lithium alloys.

The melting point of scandium is 1541 ℃, the melting point of aluminum is 660.37 ℃, and scandium is directly added into the aluminum-lithium alloy, so that the method not only needs higher temperature, consumes excessive resources and pollutes the environment, but also easily causes serious segregation and segregation of scandium in the aluminum-lithium alloy. Therefore, scandium is commonly added in the form of an Al-2Sc master alloy in industrial processes. According to the Al-Sc binary phase diagram, in order to introduce scandium into the matrix in the alloy, the temperature is raised to 813 ℃. For aluminum lithium alloy, the problem of serious hydrogen absorption and lithium loss is caused by overhigh temperature heat preservation, and unmelted coarse Al is formed₃The Sc phase makes the mechanical properties of the alloy not reach ideal states. For example, in the method for adding scandium element in the aluminum-lithium alloy mentioned in the document "research on microstructure and mechanical behavior of cast Al-Li-Cu-Mn alloy", Al-2Sc master alloy is added at 800-810 ℃ and the temperature is kept for 15 min. Meanwhile, in patent CN109402472A, an Al-Cu-Li-Sc-Zr alloy for additive manufacturing and a preparation method thereof are disclosed, specifically, a crucible is heated to 800-900 ℃, an Al-Sc intermediate alloy is added, and after the intermediate alloy is completely melted, heat preservation is carried out for 5-15 min. In both modes, scandium is added into the aluminum-lithium alloy, so that hydrogen absorption is serious, and although a subsequent refining process is performed, a great deal of hydrogen remains and primary phase Al is overlarge₃Sc distributionIn the crystal interior and on the crystal boundary, the mechanical property of the casting is seriously damaged. For the above reasons, there is a need for a preparation method that is simple to operate and can complete scandium alloying at a lower temperature.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to solve the problems of high heat preservation temperature, serious hydrogen absorption phenomenon, non-uniform components and large aluminum-scandium phase in the conventional method for introducing scandium element, namely adding aluminum-scandium master alloy, and provides the method for adding scandium element in the aluminum-lithium alloy by directly adding mixed salt into a melt.

The purpose of the invention can be realized by the following scheme:

the invention provides a method for adding scandium element in an aluminum-lithium alloy, which is characterized in that a mixed molten salt containing lithium chloride, potassium chloride, lithium fluoride and scandium trifluoride is added into the aluminum-lithium alloy to perform a substitution reaction with the melt, so that the scandium element is added into the aluminum-lithium alloy.

According to one embodiment of the present invention, in the mixed molten salt, the weight ratio of lithium chloride, potassium chloride, lithium fluoride and scandium trifluoride is 6 to 9: 6-9: 3-5: 1 to 3.

As an embodiment of the present invention, the mixed molten salt is produced by:

mixing lithium chloride, potassium chloride, lithium fluoride and scandium trifluoride to obtain a mixture; and drying the obtained mixture, heating the dried mixture, and keeping the temperature of the heated mixture in a stirring state to obtain the mixed molten salt.

In one embodiment of the present invention, the lithium chloride, potassium chloride, lithium fluoride and scandium trifluoride before mixing are in the form of powder. The powdery mixed salt has large specific surface area, is easy to melt when added into a melt, has larger contact area and can react more quickly and fully.

As an embodiment of the invention, the crucible is preheated before the mixture is heated.

As an embodiment of the invention, the temperature of the drying is 170-210 ℃; the drying time is 40-60 min.

According to one embodiment of the invention, the heating temperature is 750-850 ℃, and the heat preservation time is 20-40 min.

According to one embodiment of the invention, the temperature of the mixed molten salt when the mixed molten salt is added into the alloy is 720-750 ℃; the reaction time is 30-60 min.

In one embodiment of the invention, when the mixed molten salt and the melt react, the mixed molten salt and the melt are stirred under the condition of heat preservation, the stirring time is 5-10 min, and the stirring time interval is 5-10 min.

In one embodiment of the invention, the vessel used for mixing the molten salt and reacting the molten salt with the alloy melt is made of graphite. The container used for melting the mixed salt is a crucible. The graphite container will not react with the melt, and if the steel container is used, Fe element impurity is easy to be introduced.

In one embodiment of the present invention, the amount of the mixed molten salt added is 2 to 5 wt.% of the aluminum-lithium alloy.

Compared with the prior art, the invention has the following beneficial effects:

1) the invention provides a method for adding scandium element into an aluminum-lithium alloy through scandium-containing mixed salt on the basis of ensuring the actual yield of scandium. The method reduces the melting point of the mixed molten salt by introducing the potassium chloride and the lithium chloride with low melting points, and effectively avoids the problem of serious hydrogen absorption caused by overhigh heat preservation temperature when the aluminum-scandium intermediate alloy is added. In addition, the potassium chloride can increase the spreadability of the molten salt and reduce the density, so that the molten salt can react in the melt more quickly and fully. Meanwhile, lithium chloride and lithium fluoride are used as effective covering agents of the aluminum-lithium alloy, and the mixed salt has the composite effects of refining and protecting a melt while having a good refining treatment effect. And the fluoride fused salt has lower vapor pressure and good fluidity in a molten state, so that the scandium yield can be further improved.

2) The invention adopts the replacement reaction of Li + ScF in a high-temperature molten state₃→ LiF + Sc and chemical combination reaction Al + Sc → Al₃Sc directly forms an aluminum-scandium phase, so that the step of manufacturing an aluminum-scandium master alloy is omitted, and the coarse existence of the aluminum-scandium master alloy in the alloy is avoidedLarge aluminum-scandium primary phase, simple equipment requirement, lower smelting temperature and convenient industrial production.

3) The temperature range of preparation and heating of the molten salt is 750-850 ℃, and the heat preservation time is 20-40 min. The temperature interval and the heat preservation time are set, so that the mixed salt can be completely melted and uniformly mixed, the phenomenon of overburning of the molten salt is avoided, and the yield of scandium can be improved.

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples, which are set forth to provide a detailed description of the invention and a detailed description of the operation, will help those skilled in the art to further understand the present invention. It should be noted that the scope of the present invention is not limited to the following embodiments, and that several modifications and improvements made on the premise of the idea of the present invention belong to the scope of the present invention.

Example 1

In the present example, scandium element was added to an Al-Li alloy in the following manner for an Al-2Li-2Cu-0.5Mg alloy.

(1) Drying 100-mesh lithium chloride, potassium chloride, lithium fluoride and scandium trifluoride at 200 ℃ for 30min, and then mixing the components in percentage by mass: potassium chloride: lithium fluoride: scandium trifluoride ═ 9: 9: 3: 1, weighing 500g of mixed molten salt, uniformly mixing, putting into a crucible, heating to 750 ℃, melting and stirring, preserving heat for 40min, and pouring into a graphite container to prepare the mixed molten salt;

(2) weighing 1000g of alloy according to the mass ratio of Al-2Li-2Cu-0.5Mg, adding the alloy into a preheated graphite crucible one by one, after complete alloying, adding 50g of mixed molten salt into the preheated graphite crucible, heating until a molten salt block is completely molten, starting reduction reaction at 720 ℃, stirring mechanically, reacting for 60min, separating alloy liquid and mixed molten salt liquid after complete reaction, cooling to 710 ℃, pouring into a metal mold, and cooling in air.

The experimental environment is normal atmospheric pressure and is not sealed.

Randomly sampling the prepared sample, mixing three alloy tissues at different positions of the sampled alloy, weighing 0.2g of the mixed alloy tissues, dissolving the mixed alloy tissues in acid, preparing 200ml of scandium element standard solution, and detecting by adopting an ICP (inductively coupled plasma Spectroscopy) of Germany ZEISS company; and (3) measuring: the aluminum lithium alloy prepared by the method comprises the following components in percentage by mass: and (C) Sc: 0.209%, yield 92.1%.

Observing in different areas by a ZEISS microscope, and observing the Al which is fine and evenly distributed₃Sc particles and the size of alloy crystal grains is smaller.

Example 2

In the present example, scandium element was added to an Al-Li alloy in the following manner for an Al-2Li-2Cu-0.5Mg alloy.

(1) Drying 100-mesh lithium chloride, potassium chloride, lithium fluoride and scandium trifluoride at 200 ℃ for 30min, and then mixing the components in percentage by mass: potassium chloride: lithium fluoride: scandium trifluoride ═ 9: 9: 5: 3, weighing 500g of mixed molten salt, uniformly mixing, putting into a crucible, heating to 850 ℃, melting and stirring, preserving heat for 20min, and pouring into a graphite container to prepare the mixed molten salt;

(2) weighing 1000g of alloy according to the mass ratio of Al-2Li-2Cu-0.5Mg, adding the alloy into a preheated graphite crucible one by one, after all the alloy is alloyed, adding 20g of mixed molten salt into the alloy, heating until a molten salt block is completely melted, starting a reduction reaction at 750 ℃, stirring mechanically, reacting for 30min, separating an alloy liquid and a mixed molten salt liquid after the reaction is completed, cooling to 710 ℃, pouring into a metal mold, and cooling in air.

The experimental environment is normal atmospheric pressure and is not sealed.

Randomly sampling the prepared sample, mixing three alloy tissues at different positions of the sampled alloy, weighing 0.2g of the mixed alloy tissues, dissolving the mixed alloy tissues in acid, preparing 200ml of scandium element standard solution, and detecting by adopting an ICP (inductively coupled plasma Spectroscopy) of Germany ZEISS company; and (3) measuring: the aluminum lithium alloy prepared by the method comprises the following components in percentage by mass: and (C) Sc: 0.218 percent and an actual yield of 94.5 percent.

Observing in different areas by a ZEISS microscope, and observing the Al which is fine and evenly distributed₃Sc particles and the size of alloy crystal grains is smaller.

Example 3

In the present example, scandium element was added to an Al-Li alloy in the following manner for an Al-2Li-2Cu-0.5Mg alloy.

(1) Drying 100-mesh lithium chloride, potassium chloride, lithium fluoride and scandium trifluoride at 200 ℃ for 30min, and then mixing the components in percentage by mass: potassium chloride: lithium fluoride: scandium trifluoride ═ 9: 9: 4: 2, weighing 500g of mixed molten salt, uniformly mixing, putting into a crucible, heating to 800 ℃, melting and stirring, preserving heat for 30min, and pouring into a graphite container to prepare the mixed molten salt;

(2) weighing 1000g of alloy according to the mass ratio of Al-2Li-2Cu-0.5Mg, adding the alloy into a preheated graphite crucible one by one, after all the alloy is alloyed, adding 30g of mixed molten salt into the alloy, heating until a molten salt block is completely melted, starting a reduction reaction at 740 ℃, stirring mechanically, reacting for 40min, separating an alloy liquid and a mixed molten salt liquid after the reaction is completed, cooling to 710 ℃, pouring into a metal mold, and cooling in air.

The experimental environment is normal atmospheric pressure and is not sealed.

Randomly sampling the prepared sample, mixing three alloy tissues at different positions of the sampled alloy, weighing 0.2g of the mixed alloy tissues, dissolving the mixed alloy tissues in acid, preparing 200ml of scandium element standard solution, and detecting by adopting an ICP (inductively coupled plasma Spectroscopy) of Germany ZEISS company; and (3) measuring: the aluminum lithium alloy prepared by the method comprises the following components in percentage by mass: and (C) Sc: 0.244% and an actual yield of 97.6%.

Observing in different areas by a ZEISS microscope, and observing the Al which is fine and evenly distributed₃Sc particles and the size of alloy crystal grains is smaller.

Example 4

In the present example, scandium element was added to an Al-Li alloy in the following manner for an Al-2Li-2Cu-0.5Mg alloy.

(1) Drying 100-mesh lithium chloride, potassium chloride, lithium fluoride and scandium trifluoride at 200 ℃ for 30min, and then mixing the components in percentage by mass: potassium chloride: lithium fluoride: scandium trifluoride ═ 9: 9: 4: 2, weighing 500g of mixed molten salt, uniformly mixing, putting into a crucible, heating to 780 ℃, melting and stirring, preserving heat for 35min, and pouring into a graphite container to prepare the mixed molten salt;

(2) weighing 1000g of alloy according to the mass ratio of Al-2Li-2Cu-0.5Mg, adding the alloy into a preheated graphite crucible one by one, after all the alloy is alloyed, adding 20g of mixed molten salt into the alloy, heating until a molten salt block is completely melted, starting a reduction reaction at 730 ℃, stirring mechanically, reacting for 50min, separating an alloy liquid and a mixed molten salt liquid after the reaction is completed, cooling to 710 ℃, pouring into a metal mold, and cooling in air.

The experimental environment is normal atmospheric pressure and is not sealed.

Randomly sampling the prepared sample, mixing three alloy tissues at different positions of the sampled alloy, weighing 0.2g of the mixed alloy tissues, dissolving the mixed alloy tissues in acid, preparing 200ml of scandium element standard solution, and detecting by adopting an ICP (inductively coupled plasma Spectroscopy) of Germany ZEISS company; and (3) measuring: the aluminum lithium alloy prepared by the method comprises the following components in percentage by mass: and (C) Sc: 0.246% and an actual yield of 98.4%.

When observed with a ZEISS microscope in various regions, Al was hardly observed₃Sc particles and the size of alloy crystal grains is smaller.

Example 5

In the present example, scandium element was added to an Al-Li alloy in the following manner for an Al-2Li-2Cu-0.5Mg alloy.

(1) Drying 100-mesh lithium chloride, potassium chloride, lithium fluoride and scandium trifluoride at 200 ℃ for 30min, and then mixing the components in percentage by mass: potassium chloride: lithium fluoride: scandium trifluoride ═ 9: 9: 4: 2, weighing 500g of mixed molten salt, uniformly mixing, putting into a crucible, heating to 820 ℃, melting and stirring, keeping the temperature for 25min, and pouring into a graphite container to prepare the mixed molten salt;

(2) weighing 1000g of alloy according to the mass ratio of Al-2Li-2Cu-0.5Mg, adding the alloy into a preheated graphite crucible one by one, after all the alloy is alloyed, adding 20g of mixed molten salt into the alloy, heating until a molten salt block is completely melted, starting a reduction reaction at 735 ℃ with mechanical stirring for 45min, separating an alloy liquid and a mixed molten salt liquid after the reaction is completed, cooling to 710 ℃, pouring into a metal mold, and cooling in air.

The experimental environment is normal atmospheric pressure and is not sealed.

Randomly sampling the prepared sample, mixing three alloy tissues at different positions of the sampled alloy, weighing 0.2g of the mixed alloy tissues, dissolving the mixed alloy tissues in acid, preparing 200ml of scandium element standard solution, and detecting by adopting an ICP (inductively coupled plasma Spectroscopy) of Germany ZEISS company; and (3) measuring: the aluminum lithium alloy prepared by the method comprises the following components in percentage by mass: and (C) Sc: 0.248 percent and an actual yield of 99.2 percent.

Observing in different areas by a ZEISS microscope, and observing the Al which is fine and evenly distributed₃Sc particles and the size of alloy crystal grains is smaller.

Example 6

In the present example, scandium element was added to an Al-lithium alloy in the following procedure for an Al-3Li-1.5Cu-0.15Zr alloy.

(1) Drying 100-mesh lithium chloride, potassium chloride, lithium fluoride and scandium trifluoride at 200 ℃ for 30min, and then mixing the components in percentage by mass: potassium chloride: lithium fluoride: scandium trifluoride ═ 9: 9: 4: 2, weighing 500g of mixed molten salt, uniformly mixing, putting into a crucible, heating to 800 ℃, melting and stirring, preserving heat for 30min, and pouring into a graphite container to prepare the mixed molten salt;

(2) weighing 1000g of alloy according to the mass ratio of Al-3Li-1.5Cu-0.15Zr, adding the alloy into a preheated graphite crucible one by one, after complete alloying, adding 30g of mixed molten salt into the alloy, heating until a molten salt block is completely molten, starting reduction reaction at 740 ℃, stirring mechanically, reacting for 40min, separating alloy liquid and mixed molten salt liquid after complete reaction, cooling to 710 ℃, pouring into a metal mold, and cooling in air.

The experimental environment is normal atmospheric pressure and is not sealed.

Randomly sampling the prepared sample, mixing three alloy tissues at different positions of the sampled alloy, weighing 0.2g of the mixed alloy tissues, dissolving the mixed alloy tissues in acid, preparing 200ml of scandium element standard solution, and detecting by adopting an ICP (inductively coupled plasma Spectroscopy) of Germany ZEISS company; and (3) measuring: the aluminum lithium alloy prepared by the method comprises the following components in percentage by mass: and (C) Sc: 0.235 percent and the actual yield is 93.1 percent.

Observing in different areas by a ZEISS microscope, and observing the Al which is fine and evenly distributed₃Sc particles and the size of alloy crystal grains is smaller.

Example 7

In this example, scandium was added to an Al-Li alloy in the following manner for an Al-1.5Cu-3.5Li-0.3Mg-0.08Ag alloy.

(1) Drying 100-mesh lithium chloride, potassium chloride, lithium fluoride and scandium trifluoride at 200 ℃ for 30min, and then mixing the components in percentage by mass: potassium chloride: lithium fluoride: scandium trifluoride ═ 9: 9: 5: 3, weighing 500g of mixed molten salt, uniformly mixing, putting into a crucible, heating to 850 ℃, melting and stirring, preserving heat for 20min, and pouring into a graphite container to prepare the mixed molten salt;

(2) weighing 1000g of alloy according to the mass ratio of Al-1.5Cu-3.5Li-0.3Mg, adding the alloy into a preheated graphite crucible one by one, adding 20g of mixed molten salt into the alloy after the alloy is completely alloyed, heating until a molten salt block is completely melted, starting a reduction reaction at 750 ℃, stirring mechanically, reacting for 30min, separating an alloy liquid and the mixed molten salt liquid after the reaction is completely finished, cooling to 710 ℃, pouring into a metal mold, and cooling in air.

The experimental environment is normal atmospheric pressure and is not sealed.

Randomly sampling the prepared sample, mixing three alloy tissues at different positions of the sampled alloy, weighing 0.2g of the mixed alloy tissues, dissolving the mixed alloy tissues in acid, preparing 200ml of scandium element standard solution, and detecting by adopting an ICP (inductively coupled plasma Spectroscopy) of Germany ZEISS company; and (3) measuring: the aluminum lithium alloy prepared by the method comprises the following components in percentage by mass: and (C) Sc: 0.218 percent and an actual yield of 94.5 percent.

Observing in different areas by a ZEISS microscope, and observing the Al which is fine and evenly distributed₃Sc particles and the size of alloy crystal grains is smaller.

Comparative example 1

In the comparative example, scandium was added to an Al-Li alloy in accordance with the following procedure for an Al-2Li-2Cu-0.5Mg alloy.

(1) 100-mesh lithium chloride, lithium fluoride and scandium trifluoride (without potassium chloride) were dried at 200 ℃ for 30min, and then the ratio by mass of lithium chloride: lithium fluoride: scandium trifluoride ═ 9: 4: 2, weighing 500g of mixed molten salt, uniformly mixing, putting into a crucible, heating to 800 ℃, melting and stirring, preserving heat for 30min, and pouring into a graphite container to prepare the mixed molten salt;

(2) weighing 1000g of alloy according to the mass ratio of Al-2Li-2Cu-0.5Mg, adding the alloy into a preheated graphite crucible one by one, after all the alloy is alloyed, adding 30g of mixed molten salt into the alloy, heating until a molten salt block is completely melted, starting a reduction reaction at 740 ℃, stirring mechanically, reacting for 40min, separating an alloy liquid and a mixed molten salt liquid after the reaction is completed, cooling to 710 ℃, pouring into a metal mold, and cooling in air.

The experimental environment is normal atmospheric pressure and is not sealed.

Randomly sampling the prepared sample, mixing three alloy tissues at different positions of the sampled alloy, weighing 0.2g of the mixed alloy tissues, dissolving the mixed alloy tissues in acid, preparing 200ml of scandium element standard solution, and detecting by adopting an ICP (inductively coupled plasma Spectroscopy) of Germany ZEISS company; and (3) measuring: the aluminum lithium alloy prepared by the method comprises the following components in percentage by mass: and (C) Sc: 0.126% and an actual yield of 47.2%.

Observations were made in different areas with ZEISS microscope, Al₃Less Sc phase, uneven distribution, larger size and unobvious grain refining effect.

Comparative example 2

In the comparative example, scandium was added to an Al-Li alloy in accordance with the following procedure for an Al-2Li-2Cu-0.5Mg alloy.

(1) 100-mesh lithium chloride, potassium chloride and scandium trifluoride (containing no lithium fluoride) were dried at 200 ℃ for 30min, and then the mass ratio of lithium chloride: potassium chloride: scandium trifluoride ═ 9: 9: 2, weighing 500g of mixed molten salt, uniformly mixing, putting into a crucible, heating to 800 ℃, melting and stirring, preserving heat for 30min, and pouring into a graphite container to prepare the mixed molten salt;

(2) weighing 1000g of alloy according to the mass ratio of Al-2Li-2Cu-0.5Mg, adding the alloy into a preheated graphite crucible one by one, after all the alloy is alloyed, adding 30g of mixed molten salt into the alloy, heating until a molten salt block is completely melted, starting a reduction reaction at 740 ℃, stirring mechanically, reacting for 40min, separating an alloy liquid and a mixed molten salt liquid after the reaction is completed, cooling to 710 ℃, pouring into a metal mold, and cooling in air.

The experimental environment is normal atmospheric pressure and is not sealed.

Randomly sampling the prepared sample, mixing three alloy tissues at different positions of the sampled alloy, weighing 0.2g of the mixed alloy tissues, dissolving the mixed alloy tissues in acid, preparing 200ml of scandium element standard solution, and detecting by adopting an ICP (inductively coupled plasma Spectroscopy) of Germany ZEISS company; and (3) measuring: the aluminum lithium alloy prepared by the method comprises the following components in percentage by mass: and (C) Sc: 0.126% and an actual yield of 47.2%.

Observations were made in different areas with ZEISS microscope, Al₃The Sc phase is less, the distribution is uneven, the size is larger, a large amount of oxide inclusions are contained, the mechanical property is generally lower, and the grain refining effect is not obvious.

Comparative example 3

In the comparative example, scandium was added to an Al-Li alloy in accordance with the following procedure for an Al-2Li-2Cu-0.5Mg alloy.

(1) Drying 100-mesh lithium chloride, potassium chloride, lithium fluoride and scandium trifluoride at 200 ℃ for 30min, and then mixing the components in percentage by mass: potassium chloride: lithium fluoride: scandium trifluoride ═ 9: 9: 5: 3, weighing 500g of mixed molten salt, uniformly mixing, putting into a crucible, heating to 850 ℃, melting and stirring, preserving heat for 20min, and pouring into a graphite container to prepare the mixed molten salt;

(2) weighing 1000g of alloy according to the mass ratio of Al-2Li-2Cu-0.5Mg, adding the alloy into a preheated graphite crucible one by one, after all the alloy is alloyed, adding 20g of mixed molten salt into the alloy, heating until a molten salt block is completely melted, starting a reduction reaction at 850 ℃ with mechanical stirring for 20min, separating an alloy liquid and a mixed molten salt liquid after the reaction is completed, cooling to 710 ℃, pouring into a metal mold, and cooling in air.

The experimental environment is normal atmospheric pressure and is not sealed.

Randomly sampling the prepared sample, mixing three alloy tissues at different positions of the sampled alloy, weighing 0.2g of the mixed alloy tissues, dissolving the mixed alloy tissues in acid, preparing 200ml of scandium element standard solution, and detecting by adopting an ICP (inductively coupled plasma Spectroscopy) of Germany ZEISS company; and (3) measuring: the aluminum lithium alloy prepared by the method comprises the following components in percentage by mass: and (C) Sc: 0.193%, found 83.6%, while the Li content was only 1.31%, found 65.5%

Observations were made in different areas with ZEISS microscope, Al₃Sc is relatively less, lithium burning loss is serious due to overhigh reaction temperature, and the ingot has more pores and contains a large amount of oxide inclusions due to serious hydrogen absorption.

Comparative example 4

In the comparative example, scandium was added to an Al-Li alloy in accordance with the following procedure for an Al-2Li-2Cu-0.5Mg alloy.

Weighing 1000g of alloy according to the mass ratio of Al-2Li-2Cu-0.5Mg, adding the alloy into a preheated graphite crucible one by one, after the alloy is completely alloyed, adding 100g of Al-2Sc master alloy into the preheated graphite crucible at 820 ℃, preserving the heat for 15min, cooling to 710 ℃, pouring into a metal mold, and cooling in air.

The experimental environment is normal atmospheric pressure and is not sealed.

Randomly sampling the prepared sample, mixing three alloy tissues at different positions of the sampled alloy, weighing 0.2g of the mixed alloy tissues, dissolving the mixed alloy tissues in acid, preparing 200ml of scandium element standard solution, and detecting by adopting an ICP (inductively coupled plasma Spectroscopy) of Germany ZEISS company; and (3) measuring: the aluminum lithium alloy prepared by the method comprises the following components in percentage by mass: and (C) Sc: 0.109%, yield 53.4%.

Coarse Al observed in different areas with ZEISS microscope₃The Sc phase is randomly distributed on the crystal boundary and in the crystal, so that the mechanical property of the Sc phase is poor, and the grain refining effect is poor.

Comparative example 5

In this example, scandium was added to an Al-Li alloy in the following manner for an Al-1.5Cu-3.5Li-0.3Mg-0.08Ag alloy.

(1) Drying 100-mesh lithium chloride, potassium chloride, lithium fluoride and scandium trifluoride at 200 ℃ for 30min, and then mixing the components in percentage by mass: potassium chloride: lithium fluoride: scandium trifluoride ═ 9: 9: 5: 3, weighing 500g of mixed molten salt, uniformly mixing, putting into a crucible, heating to 700 ℃, melting and stirring, preserving heat for 60min, and pouring into a graphite container to prepare the mixed molten salt;

(2) weighing 1000g of alloy according to the mass ratio of Al-1.5Cu-3.5Li-0.3Mg, adding the alloy into a preheated graphite crucible one by one, adding 20g of mixed molten salt into the alloy after the alloy is completely alloyed, heating until a molten salt block is completely melted, starting a reduction reaction at 750 ℃, stirring mechanically, reacting for 30min, separating an alloy liquid and the mixed molten salt liquid after the reaction is completely finished, cooling to 710 ℃, pouring into a metal mold, and cooling in air.

The experimental environment is normal atmospheric pressure and is not sealed.

Randomly sampling the prepared sample, mixing three alloy tissues at different positions of the sampled alloy, weighing 0.2g of the mixed alloy tissues, dissolving the mixed alloy tissues in acid, preparing 200ml of scandium element standard solution, and detecting by adopting an ICP (inductively coupled plasma Spectroscopy) of Germany ZEISS company; and (3) measuring: the aluminum lithium alloy prepared by the method comprises the following components in percentage by mass: and (C) Sc: 0.171%, yield 74.3%.

When observed in different regions with a ZEISS microscope, the distribution of uniformly distributed fine Al3Sc particles was observed, but the yield of scandium was low.

Comparative example 6

In the present example, scandium element was added to an Al-lithium alloy in the following procedure for an Al-3Li-1.5Cu-0.15Zr alloy.

(1) Drying 100-mesh lithium chloride, potassium chloride, lithium fluoride and scandium trifluoride at 200 ℃ for 30min, and then mixing the components in percentage by mass: potassium chloride: lithium fluoride: scandium trifluoride ═ 1: 1: 1: 1, weighing 500g of mixed molten salt, uniformly mixing, putting into a crucible, heating to 800 ℃, melting and stirring, preserving heat for 30min, and pouring into a graphite container to prepare the mixed molten salt;

(2) weighing 1000g of alloy according to the mass ratio of Al-3Li-1.5Cu-0.15Zr, adding the alloy into a preheated graphite crucible one by one, adding 10g of mixed molten salt into the alloy after the alloy is completely alloyed, heating until a molten salt block is completely melted, starting a reduction reaction at 740 ℃, stirring mechanically, reacting for 40min, separating an alloy liquid and the mixed molten salt liquid after the reaction is completely finished, cooling to 710 ℃, pouring into a metal mold, and cooling in air.

The experimental environment is normal atmospheric pressure and is not sealed.

Randomly sampling the prepared sample, mixing three alloy tissues at different positions of the sampled alloy, weighing 0.2g of the mixed alloy tissues, dissolving the mixed alloy tissues in acid, preparing 200ml of scandium element standard solution, and detecting by adopting an ICP (inductively coupled plasma Spectroscopy) of Germany ZEISS company; and (3) measuring: the aluminum lithium alloy prepared by the method comprises the following components in percentage by mass: and (C) Sc: 0.195% and an actual yield of 78%.

Observations were made in different areas with ZEISS microscope, Al₃The Sc phase is non-uniform in distribution, large in size and low in scandium yield.

The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes and modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention.