Preparation method of beryllium-aluminum alloy with high beryllium content

Abstract

The present invention relates to a preparation method of a beryllium-aluminum alloy with a high beryllium content. Through the synergistic compounding effect of ammonium fluoberyllate and a refining agent, a series of physical and chemical actions are carried out to remove harmful impurities such as hydrogen and oxide inclusions from the molten alloy liquid. The two cooperate synergistically to reduce the dosage of the refining agent, with a large gas generation amount and a simple refining process. By adding other metal elements such as cobalt, nickel, and germanium to the preparation process of the beryllium-aluminum alloy and cooperating with a specific casting process, the beryllium-aluminum alloy with a high beryllium content prepared by the present invention has excellent comprehensive properties.

Description

Technical Field

[0001] The present invention belongs to the field of alloys, and particularly relates to a preparation method of a beryllium-aluminum alloy with a high beryllium content. Background Art

[0002] A beryllium-aluminum alloy with a high beryllium content refers to a beryllium-aluminum alloy with a beryllium content of more than 60%. It has a high beryllium content and excellent properties. The beryllium-aluminum alloy with a high beryllium content has also become Lockalloy. It was first developed by the American company Nuclear Metal, with a beryllium content of about 62%. It has excellent mechanical properties and is applied to some high-end manufacturing industries, such as aerospace and fighter jets. The manufacturing methods of the beryllium-aluminum alloy with a high beryllium content mainly include powder metallurgy and precision casting. The alloy products obtained by the powder metallurgy method have good quality, but the process is complex, and the technical core is currently mostly mastered by foreign companies. If the process is improper, it is difficult to obtain a beryllium-aluminum alloy with good quality. The precision casting process is simple and the manufacturing cost is low, so it is widely used by domestic manufacturers. In order to prepare a high-quality beryllium-aluminum alloy with a high beryllium content by the precision casting process, different alloy elements are often added and the treatment process is optimized to improve the various properties of the beryllium-aluminum alloy, especially to overcome the problem of poor toughness caused by the high beryllium content.

[0003] There are reports in the prior art on improving the cast beryllium-aluminum alloy by adding elements such as Ag, Mg, Ni, Co, Ge, etc. However, in the casting process, the melting points of the beryllium and aluminum phases differ greatly. The melting point of beryllium is 1287°C, and the melting point of aluminum is 661°C. The mutual solubility is low, and no intermetallic compound is formed. The solidification temperature range of the beryllium-aluminum alloy is wide, resulting in defects such as shrinkage cavities and shrinkage porosity in the prepared beryllium-aluminum alloy; in addition, aluminum is prone to enrichment at the interface of the beryllium-aluminum alloy, resulting in segregation of aluminum and a decline in various properties.

[0004] The casting process of the beryllium-aluminum alloy is carried out at high temperature, which is likely to generate solid impurity particles and dross on the surface of the melt, resulting in structural defects such as inclusions and pores, causing a decline in strength. Generally, a refining agent / slag remover needs to be added for treatment, and the refining agent system in the prior art still cannot meet the manufacturing requirements of the beryllium-aluminum alloy with a high beryllium content.

[0005] The previous patent CN202311786007.6 of the inventor disclosed a preparation method of beryllium-aluminum alloy, which used ammonium fluoberyllate and a compound refining agent in combination to obtain a beryllium-aluminum alloy with excellent comprehensive properties. However, when the beryllium content is further increased, the preparation process still needs to be further improved. In order to overcome the huge difference in the solubility of beryllium and aluminum, resulting in a very low solid solubility between the two, the beryllium phase and the aluminum phase are basically two separate pure phases. This patent used a beryllium-tin-zinc mixed melt instead of a beryllium melt to reduce the defect of a huge difference in melting point. However, the inventor found that when the beryllium content increased to more than 50%, the casting process of this patent began to be difficult to match, and it was impossible to obtain a beryllium-aluminum alloy with high beryllium content and excellent performance. This may be because the small amounts of Zn and Sn added are not suitable for the components of the high-beryllium-content beryllium-aluminum alloy. Therefore, further research on the manufacturing process of high-beryllium-content beryllium-aluminum alloy is still needed. Summary of the Invention

[0006] In order to solve the problem that there is still a lack of an effective manufacturing method for high-beryllium-content beryllium-aluminum alloy in the prior art, the present invention improves the properties of high-beryllium-content beryllium-aluminum alloy, especially the defect of poor toughness, by adding a compound refining agent and ammonium fluoberyllate in a synergistic manner and optimizing the casting process. The present invention achieves the above object through the following technical solutions:

[0007] A preparation method of high-beryllium-content beryllium-aluminum alloy, comprising the following steps:

[0008] (S1) Mix 10-15 parts by mass of aluminum, 1.1-1.7 parts by mass of cobalt, and 2-3 parts by mass of nickel evenly, and vacuum melt at 1450-1550 °C to obtain an aluminum-cobalt-nickel mixed melt;

[0009] [[ID=1】4]](S2) Mix 5-8 parts by mass of aluminum and 0.4-0.7 parts by mass of ammonium fluoberyllate evenly, and vacuum melt at 660-720 °C to obtain an aluminum melt containing ammonium fluoberyllate,

[0010] (S3) Mix 70-75 parts by mass of beryllium, 15-20 parts by mass of aluminum, and 3-5 parts by mass of germanium evenly, vacuum melt into a melt at 1450-1550 °C, add the aluminum-cobalt-nickel mixed melt obtained in step (S1), hold at 1450-1550 °C for 1-2 h, add the aluminum melt containing ammonium fluoberyllate obtained in step (S2), continue melting, remove the surface scum, add 0.5-0.8 parts by mass of a refining agent, hold for refining, and obtain a mixed melt;

[0011] (S4) Pour the mixed melt obtained in step (S3) into a mold, cool slowly first, and then cool quickly to obtain a beryllium-aluminum alloy blank;

[0012] (S5) Perform degassing treatment and hot isostatic pressing treatment on the beryllium-aluminum alloy blank obtained in step (S4) to obtain a high-beryllium-content beryllium-aluminum alloy.

[0013] The inventors unexpectedly found that preparing the alloy in the form of a mixed melt of aluminum, cobalt, and nickel results in better product performance than directly mixing and melting the raw materials.

[0014] In the present invention, the metallic aluminum raw material is added in three parts. One part is made into an aluminum-cobalt-nickel mixed melt, one part is made into an aluminum melt containing ammonium fluoberyllate, and the last remaining part is made into a beryllium-aluminum-germanium mixed melt after being mixed with beryllium and germanium.

[0015] Ammonium fluoberyllate decomposes into beryllium fluoride and ammonium fluoride at 900 °C. Ammonium fluoride does not dissolve in the melt and does not introduce new impurities, and it plays a role in removing impurities and exhausting gas through floating. The inventors unexpectedly found that when ammonium fluoberyllate is combined with a refining agent, the strength performance indexes of the obtained beryllium-aluminum alloy are all improved to a certain extent. In the refining agent of the present invention, conventional refining agents such as hexachloroethane are not added, and no carbon element is introduced, reducing the structural defect problems caused by the introduction of carbon elements. Fluorides can react with impurities in the aluminum liquid to form fluorides or fluorine oxides, accelerating the separation of impurities and the alloy liquid; the presence of fluorides can also increase the surface tension between the refining agent and the alloy liquid, making it easy to separate the refining agent and the alloy liquid, accelerating the adsorption of hydrogen and oxide inclusions in the alloy liquid by the refining agent, reducing the metal loss of beryllium, and lowering the manufacturing cost. In the present invention, if ammonium fluoberyllate is directly added to the mixed melt, due to the high temperature, it is easy to instantly release gas on the surface of the melt, affecting the strength, and it cannot well play the synergistic effect with the refining agent; therefore, during the preparation process of the beryllium-aluminum alloy in the present invention, ammonium fluoberyllate is mixed with part of the aluminum. Since the melting point of aluminum is about 660 °C, ammonium fluoberyllate will not decompose during the melting process, and an aluminum melt containing ammonium fluoberyllate is obtained after melting. The ammonium fluoberyllate of the present invention is used in combination with a specific refining agent, reducing the dosage of the refining agent, having a large gas generation amount, and the refining process is simple.

[0016] Further, in the above preparation method, beryllium accounts for 60-65 wt%, preferably 62-63 wt% of the total mass of the metal raw materials.

[0017] Further, the purity of the metal raw materials used in the present invention is ≥99.9%, preferably ≥99.99%. Using high-purity metal raw materials results in low impurity content in the product, which helps to improve the alloy quality.

[0018] Further, the vacuum melting is carried out in a vacuum induction furnace, and the vacuum degree is 1×10 -3 to 1×10 -2 Pa.

[0019] Further, in step (S3), the refining agent is a mixture of sodium fluoroborate, borax, and beryllate, and the beryllate is selected from at least one of sodium beryllate and potassium beryllate.

[0020] Furthermore, the refining agent is a mixture of sodium fluoroborate, borax, and beryllate in a mass ratio of 32 - 45:11 - 17:13 - 20.

[0021] Further, the refining agent is obtained through a preparation method including the following steps: After mixing sodium fluoroborate, borax, and beryllate, it is dehydrated at high temperature. Furthermore, the mixing is ball milling, and the process conditions of ball milling are well-known in the art. For example, in a specific embodiment of the present invention, the ball-to-material ratio of ball milling is 20 - 40:1, the rotation speed is 400 - 600 rpm, and the ball milling time is 2 - 4 h; the high-temperature dehydration is carried out under a protective atmosphere at 300 - 350 °C for 4 - 10 h, and the water content of the obtained refining agent is ≤10 ppm.

[0022] Further, in step (S3), the refining agent can be evenly spread on the surface of the melt and pressed into the melt; or a spraying machine can be used to spray the refining agent into the melt. Preferably, the method of spraying the refining agent into the melt using a spraying machine makes the distribution of the refining agent more uniform and the refining effect better. The temperature for holding and refining is maintained at 1100 - 1200 °C, and the holding and refining time is 1 - 2 h.

[0023] Further, in step (S4), the material of the mold is ceramic, slow cooling is carried out by magnetic field cooling, the cooling rate is controlled at 1 - 5 °C / s, and it is slowly cooled to 1000 - 1050 °C, and then rapid cooling is carried out. Rapid cooling is carried out by strong wind cooling, and the cooling rate is 140 - 180 °C / s. The present invention adopts the method of first slow cooling and then rapid cooling, which strengthens the solid solution treatment of the alloy and is more conducive to strengthening the interaction between the beryllium phase and other metal phases.

[0024] Further, in step (S5), the temperature of the degassing treatment is 500 - 600 °C, the vacuum degree is ≤5×10 -3 Pa, and the degassing time is 3 - 5 h; the temperature of the hot isostatic pressing treatment is 600 - 700 °C, the pressure is 120 - 150 MPa, and the treatment time is 3 - 5 h.

[0025] Further, steps (S1) to (S4) are all carried out under a protective atmosphere, and the protective atmosphere is argon and / or nitrogen.

[0026] Compared with the prior art, the present invention has made the following technological progress:

[0027] First, through the synergistic compounding effect of ammonium fluoberyllate and the refining agent, through a series of physical and chemical actions, harmful impurities such as hydrogen and oxide inclusions in the molten alloy liquid are removed. The two cooperate synergistically, reducing the dosage of the refining agent, having a large gas generation amount, and the refining process is simple.

[0028] II. By adding other metal elements such as cobalt, nickel, and germanium to the preparation process of beryllium-aluminum alloy and combining with a specific casting process, the beryllium-aluminum alloy with a high beryllium content prepared by the present invention has excellent comprehensive properties. Description of the Drawings

[0029] Figure 1 It is a photograph of the beryllium-aluminum alloy ingot with a high beryllium content obtained in Example 1. Detailed Embodiments

[0030] The following uses specific examples to further explain and illustrate the content of the present invention.

[0031] In the embodiments of the present invention, unless otherwise specified, the parts are in mass parts; the %, unless otherwise specified, are in mass percentages.

[0032] The purity of the materials used in the embodiments of the present invention is ≥99.9%.

[0033] Preparation of the Refining Agent in the Preparation Example

[0034] After mixing sodium fluoroborate, borax, and beryllate evenly by ball milling, the process conditions of ball milling are a ball-to-material ratio of 30:1, a rotation speed of 400 rpm, a ball milling time of 4 h, and heat treatment at 300 °C for 6 h under a high nitrogen atmosphere to make the water content of the refining agent ≤10 ppm.

[0035] Example 1

[0036] (S1) Mix 15 parts by mass of aluminum, 1.1 parts by mass of cobalt, and 3 parts by mass of nickel evenly, and vacuum melt (vacuum degree ≤ 1×10 -3 Pa) at 1500 °C to obtain an aluminum-cobalt-nickel mixed melt;

[0037] (S2) Mix 5 parts by mass of aluminum and 0.4 parts by mass of ammonium fluoberyllate evenly, and vacuum melt at 710 °C to obtain an aluminum melt containing ammonium fluoberyllate,

[0038] (S3) Mix 70 parts by mass of beryllium, 15 parts by mass of aluminum, and 3 parts by mass of germanium evenly, vacuum melt into a melt at 1500 °C, add the aluminum-cobalt-nickel mixed melt in step (S1), hold for 2 h at 1500 °C, add the aluminum melt containing ammonium fluoberyllate in step (S2), continue melting, remove the surface scum, spray 0.8 parts by mass of the refining agent into the melt with a spraying machine, the refining agent is a mixture of sodium fluoroborate, borax, and potassium beryllate in a mass ratio of 32:17:13, hold for refining for 2 h to obtain a mixed melt;

[0039] (S4) Pour the mixed melt obtained in step (S3) into a ceramic mold, first cool slowly in a magnetic field with a cooling rate of 1-2 °C / s, cool to 1050 °C, and then cool rapidly with strong wind with a cooling rate of about 180 °C / s to room temperature to obtain an alloy blank;

[0040] (S5) Load the alloy blank obtained in step (S4) into a low-carbon steel jacket, and perform degassing treatment in a vacuum muffle furnace. The temperature of the degassing treatment is 500 °C, the vacuum degree ≤ 5×10 -3 Pa, the degassing time is 5 h. After the degassing treatment is completed, seal it; put the low-carbon steel jacket into a hot isostatic pressing equipment, and under the conditions of 600 °C and a pressure of 150 MPa, perform hot isostatic pressing treatment for 5 h. After natural cooling, remove the low-carbon steel jacket to obtain the product high-beryllium-content beryllium aluminum alloy.

[0041] Example 2

[0042] (S1) Mix 10 parts by mass of aluminum, 1.7 parts by mass of cobalt, and 2 parts by mass of nickel evenly, and perform vacuum melting at 1500 °C (vacuum degree ≤ 1×10 -3 Pa) to obtain an aluminum-cobalt-nickel mixed melt;

[0043] (S2) Mix 8 parts by mass of aluminum and 0.7 parts by mass of ammonium fluoberyllate evenly, and perform vacuum melting at 700 °C to obtain an aluminum melt containing ammonium fluoberyllate.

[0044] (S3) Mix 70 parts by mass of beryllium, 15 parts by mass of aluminum, and 5 parts by mass of germanium evenly, and perform vacuum melting at 1500 °C to form a melt. Add the aluminum-cobalt-nickel mixed melt obtained in step (S1), hold for 2 h at 1500 °C, add the aluminum melt containing ammonium fluoberyllate obtained in step (S2), continue melting, remove the surface scum, and spray 0.5 parts by mass of a refining agent into the melt using a spraying machine. The refining agent is a mixture of sodium fluoroborate, borax, and potassium beryllate in a mass ratio of 45:11:20. Hold for refining for 2 h to obtain a mixed melt;

[0045] (S4) Pour the mixed melt obtained in step (S3) into a ceramic mold, first perform slow cooling in a magnetic field with a cooling rate of 1 - 2 °C / s, cool to 1000 °C, and then perform rapid cooling with strong wind with a cooling rate of about 180 °C / s, cool to room temperature to obtain an alloy blank;

[0046] (S5) Load the alloy blank obtained in step (S4) into a low-carbon steel jacket, and perform degassing treatment in a vacuum muffle furnace. The temperature of the degassing treatment is 500 °C, the vacuum degree ≤ 5×10 -3 Pa, the degassing time is 5 h. After the degassing treatment is completed, seal it; put the low-carbon steel jacket into a hot isostatic pressing equipment, and under the conditions of 600 °C and a pressure of 150 MPa, perform hot isostatic pressing treatment for 5 h. After natural cooling, remove the low-carbon steel jacket to obtain the product high-beryllium-content beryllium aluminum alloy.

[0047] Example 3

[0048] (S1) 13 parts by mass of aluminum, 1.5 parts by mass of cobalt, and 2.7 parts by mass of nickel were mixed uniformly and vacuum melted at 1500°C (vacuum degree ≤ 1×10 -3 Pa), to obtain an aluminum-cobalt-nickel mixed melt;

[0049] (S2) 7 parts by mass of aluminum and 0.6 parts by mass of ammonium fluoroberyllate were mixed uniformly, and vacuum-melted at 710° C. to obtain an aluminum melt containing ammonium fluoroberyllate.

[0050] (S3) 73 parts by mass of beryllium, 16 parts by mass of aluminum, and 4 parts by mass of germanium are uniformly mixed, vacuum-smelted at 1500° C. to form a melt, the aluminum-cobalt-nickel mixed melt of step (S1) is added, and the mixture is heat-treated at 1500° C. for 2 hours, and the aluminum melt containing ammonium fluoroberyllate of step (S2) is added, and the smelting is continued, and the surface scum is removed, and 0.6 parts by mass of a refining agent is sprayed into the melt using a sprayer, wherein the refining agent is a mixture of sodium fluoroborate, borax, and potassium beryllium in a mass ratio of 40:15:15, and the mixture is heat-treated and refined for 2 hours to obtain a mixed melt;

[0051] (S4) pouring the mixed melt obtained in step (S3) into a ceramic mold, first slowly cooling the mixed melt in a magnetic field at a cooling rate of 1-2°C / s to 1000°C, then rapidly cooling the mixed melt in a strong wind at a cooling rate of about 180°C / s to room temperature to obtain an alloy blank;

[0052] (S5) The alloy blank obtained in step (S4) is placed in a low-carbon steel jacket and degassed in a vacuum muffle furnace at a temperature of 500° C. and a vacuum degree of ≤5×10 -3 Pa, degassing time 5h, sealing after degassing treatment is completed; the low carbon steel jacket is placed in a hot isostatic pressing equipment, hot isostatic pressing treatment is carried out at 600℃ and pressure 150MPa for 5h, and the low carbon steel jacket is removed after natural cooling to obtain the product beryllium aluminum alloy with high beryllium content.

[0053] Comparative Example 1

[0054] Other conditions are the same as those in Example 3, except that in step (S4), the cooling method is natural cooling to room temperature.

[0055] Comparative Example 2

[0056] (S1) 20 parts by mass of aluminum, 1.5 parts by mass of cobalt, and 2.7 parts by mass of nickel were mixed uniformly and vacuum melted at 1500°C (vacuum degree ≤ 1×10 -3 Pa), to obtain an aluminum-cobalt-nickel mixed melt;

[0057] (S2) Mix 73 parts by mass of beryllium, 16 parts by mass of aluminum, and 4 parts by mass of germanium evenly, melt them in a vacuum at 1500 °C to form a melt, add the aluminum-cobalt-nickel mixed melt from step (S1), hold at 1500 °C for 2 h, remove the surface scum, spray 1.2 parts by mass of a refining agent into the melt using a spraying machine. The refining agent is a mixture of sodium fluoroborate, borax, and potassium beryllate in a mass ratio of 40:15:15. Hold for refining for 2 h to obtain a mixed melt;

[0058] (S3) Pour the mixed melt obtained in step (S2) into a ceramic mold, first cool slowly in a magnetic field at a cooling rate of 1 - 2 °C / s until it reaches 1000 °C, and then cool rapidly with strong wind at a cooling rate of about 180 °C / s until it reaches room temperature to obtain an alloy blank;

[0059] (S4) Put the alloy blank obtained in step (S3) into a low-carbon steel jacket, perform degassing treatment in a vacuum muffle furnace at a temperature of 500 °C, with a vacuum degree ≤ 5×10 -3 Pa, and the degassing time is 5 h. After completing the degassing treatment, seal it; Put the low-carbon steel jacket into a hot isostatic pressing equipment, and perform hot isostatic pressing treatment at 600 °C and a pressure of 150 MPa for 5 h. After natural cooling, remove the low-carbon steel jacket to obtain the product high-beryllium-content beryllium-aluminum alloy.

[0060] That is, compared with Example 3, in Comparative Example 2, ammonium fluoberyllate is not added, and the amount of the refining agent is 1.2 parts by mass, which is the total amount of ammonium fluoberyllate and the refining agent in Example 3.

[0061] Comparative Example 3

[0062] (S1) Mix 7 parts by mass of aluminum and 0.6 parts by mass of ammonium fluoberyllate evenly, and melt them in a vacuum at 710 °C to obtain an aluminum melt containing ammonium fluoberyllate,

[0063] (S2) Mix 73 parts by mass of beryllium, 29 parts by mass of aluminum, 4 parts by mass of germanium, 1.5 parts by mass of cobalt, and 2.7 parts by mass of nickel evenly, melt them in a vacuum at 1500 °C to form a melt, hold at 1500 °C for 2 h, add the aluminum melt containing ammonium fluoberyllate from step (S1), continue melting, remove the surface scum, spray 0.6 parts by mass of a refining agent into the melt using a spraying machine. The refining agent is a mixture of sodium fluoroborate, borax, and potassium beryllate in a mass ratio of 40:15:15. Hold for refining for 2 h to obtain a mixed melt;

[0064] (S3) Pour the mixed melt obtained in step (S2) into a ceramic mold, first cool slowly in a magnetic field at a cooling rate of 1 - 2 °C / s until it reaches 1000 °C, and then cool rapidly with strong wind at a cooling rate of about 180 °C / s until it reaches room temperature to obtain an alloy blank;

[0065] (S4) Load the alloy blank obtained in step (S3) into a low-carbon steel jacket, and perform degassing treatment in a vacuum muffle furnace. The temperature of the degassing treatment is 500 °C, the vacuum degree ≤ 5×10 -3 Pa, the degassing time is 5 h. After the degassing treatment is completed, perform sealing; put the low-carbon steel jacket into a hot isostatic pressing device, and under the conditions of 600 °C and a pressure of 150 MPa, perform hot isostatic pressing treatment for 5 h. After natural cooling, remove the low-carbon steel jacket to obtain a product, a high-beryllium-content beryllium-aluminum alloy.

[0066] That is, compared with Example 3, in Comparative Example 3, the preparation of the aluminum-cobalt-nickel mixed melt in step (S1) was cancelled, and nickel and cobalt were directly fed together in step (S2) for melting.

[0067] Application Example

[0068] Perform performance tests on the high-beryllium-content beryllium alloys obtained in the above examples and comparative examples. The results are shown in Table 1 below:

[0069] Table 1 Performance Tests of High-Beryllium-Content Beryllium-Aluminum Alloys

[0070]

[0071] It can be seen that the high-beryllium-content beryllium-aluminum alloy prepared by the preparation method of the present invention has very excellent comprehensive mechanical properties. The beryllium content is increased to more than 60%, elements such as germanium, cobalt, and nickel are added, the use of ammonium fluoberyllate and a specific refining agent is combined, and the preparation process of first preparing an aluminum-cobalt-nickel mixed melt is adopted to obtain a high-beryllium-content beryllium-aluminum alloy product with excellent mechanical properties in all aspects. The preparation method of the high-beryllium-content beryllium-aluminum alloy proposed by the present invention has a simple process and low requirements for equipment, and can meet the demand for large-scale production of high-quality high-beryllium-content beryllium-aluminum alloys.

Claims

1. A method for preparing a beryllium aluminum alloy with a high beryllium content, characterized in that: The following steps are involved: (S1) mixing 10-15 parts by mass of aluminum, 1.1-1.7 parts by mass of cobalt, and 2-3 parts by mass of nickel, and vacuum melting at 1450-1550° C. to obtain an aluminum-cobalt-nickel mixed melt; (S2) 5-8 parts by mass of aluminum and 0.4-0.7 parts by mass of ammonium fluoroberyllate are uniformly mixed, and vacuum smelted at 660-720° C. to obtain an aluminum melt containing ammonium fluoroberyllate. (S3) uniformly mixing 70-75 parts by mass of beryllium, 15-20 parts by mass of aluminum, and 3-5 parts by mass of germanium, and vacuum melting at 1450-1550° C. to form a melt, adding the aluminum-cobalt-nickel mixed melt of step (S1), and heat-treating at 1450-1550° C. for 1-2 hours, adding the aluminum melt containing ammonium fluoroberyllate of step (S2), continuing to melt, removing surface scum, adding 0.5-0.8 parts by mass of a refining agent, and heat-refining to obtain a mixed melt; (S4) pouring the mixed melt obtained in step (S3) into a mold, first slowly cooling it, and then rapidly cooling it to obtain a beryllium aluminum alloy blank; the slow cooling is performed by using magnetic field cooling, controlling the cooling rate to be 1-5°C / s, slowly cooling it to 1000-1050°C, and then rapidly cooling it, which is performed by using strong air cooling, and the cooling rate is 140-180°C / s; (S5) Degassing and hot isostatic pressing the beryllium aluminum alloy blank obtained in step (S4) to obtain a beryllium aluminum alloy with a high beryllium content.

2. The method for preparing a beryllium aluminum alloy with a high beryllium content according to claim 1, wherein: Beryllium accounts for 60-65wt% of the total mass of the metal raw materials.

3. The method for preparing a beryllium aluminum alloy with a high beryllium content according to claim 1, wherein: Beryllium accounts for 62-63wt% of the total mass of the metal raw materials.

4. The method for preparing a beryllium aluminum alloy with a high beryllium content according to claim 1, wherein: The purity of the metal raw materials used is ≥99.9%.

5. The method for preparing a beryllium aluminum alloy with a high beryllium content according to claim 1, wherein: Vacuum melting is carried out in a vacuum induction furnace with a vacuum degree of 1×10 -3 Pa to 1×10 -2 Pa.

6. The method for preparing a beryllium aluminum alloy with a high beryllium content according to claim 1, wherein: In step (S3), the refining agent is a mixture of sodium fluoroborate, borax, and beryllium salt, and the beryllium salt is selected from at least one of sodium beryllium salt and potassium beryllium salt.

7. The method for preparing a beryllium aluminum alloy with a high beryllium content according to claim 6, wherein: The refining agent is a mixture of sodium fluoroborate, borax and beryllium salt in a mass ratio of 32-45:11-17:13-20.

8. The method for preparing a beryllium aluminum alloy with a high beryllium content according to claim 6, wherein: The refining agent is obtained by a preparation method comprising the following steps: mixing sodium fluoroborate, borax and beryllium salt, and then dehydrating the mixture at high temperature.

9. The method for preparing a beryllium aluminum alloy with a high beryllium content according to claim 1, wherein: In step (S3), the refining agent is added by evenly spreading it on the surface of the melt and pressing it into the melt; or the refining agent is sprayed into the melt using a sprayer.

10. The method for preparing a beryllium aluminum alloy with a high beryllium content according to claim 1, wherein: In step (S4), the material of the mold is ceramic.

11. The method for preparing a beryllium aluminum alloy with a high beryllium content according to claim 1, wherein: In step (S5), the degassing temperature is 500-600°C, and the vacuum degree is ≤5×10 -3 Pa, degassing time 3-5h; the temperature of the hot isostatic pressing treatment is 600-700℃, the pressure is 120-150MPa, and the treatment time is 3-5h.

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