Production process of beryllium aluminum alloy with high beryllium content

Abstract

The invention discloses a production process of a beryllium aluminum alloy with high beryllium content, which belongs to the technical field of beryllium-based aluminum alloy materials and comprises the following steps: S1, weighing the following raw materials in percentage by weight: 65-75% of beryllium, 2-3% of nickel, 1-2% of refining agent, 0.05-1% of silicon and the balance of aluminum and inevitable impurities; s2, an aluminum ingot is added into a vacuum melting furnace, the temperature is increased to 200-250 DEG C, preheating is conducted for 2-3 h, then the temperature is increased to 750-780 DEG C, heat preservation is conducted for 20 min, beryllium, nickel and silicon are added, the temperature is increased to 1450-1550 DEG C, vacuum melting is conducted, a melt is prepared, a refining agent is added, heat preservation and refining are conducted, and a mixed melt is prepared; and S3, the prepared mixed melt is cast in a mold and cooled, a beryllium-aluminum alloy blank is prepared and treated, and the beryllium-aluminum alloy with the high beryllium content is prepared. By adding the refining agent, the refining effect can be remarkably improved, and the beryllium-aluminum alloy is endowed with more excellent comprehensive performance.

Description

Technical Field

[0001] The invention relates to the technical field of beryllium-based aluminum alloy materials, and in particular to a production process of a beryllium aluminum alloy with a high beryllium content. Background Art

[0002] High beryllium content beryllium aluminum alloy refers to beryllium aluminum alloy with beryllium content of more than 60%. It has high beryllium content and excellent performance. The manufacturing methods mainly include powder metallurgy and precision casting.

[0003] The existing technology improves the quality of cast beryllium aluminum alloy by adding elements such as Ag, Mg, Ni, Co, and Ge. However, the melting points of beryllium and aluminum are very different (the melting point of beryllium is 1287°C and the melting point of aluminum is 661°C), the mutual solubility is low, no intermetallic compounds are generated, and the solidification temperature range of beryllium aluminum alloy is wide, resulting in shrinkage cavities and shrinkage defects in the prepared beryllium aluminum alloy; in addition, aluminum is easily enriched at the interface of beryllium aluminum alloy, resulting in aluminum segregation, which leads to the degradation of various properties.

[0004] When beryllium aluminum alloy is cast at high temperature, solid impurity particles are easily generated, and slag is generated on the surface of the melt, resulting in structural defects such as inclusions and pores, causing strength reduction. Generally, refining agents / slag removal agents need to be added for treatment. The refining agent system in the existing technology cannot meet the manufacturing requirements of beryllium aluminum alloy with high beryllium content. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a production process of beryllium aluminum alloy with high beryllium content.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A production process of a beryllium aluminum alloy with a high beryllium content comprises the following steps:

[0008] Step S1, weighing the following raw materials in weight percentage: 65-75% beryllium, 2-3% nickel, 1-2% refining agent, 0.05-1% silicon, and the balance being aluminum and unavoidable impurities;

[0009] Step S2, adding the aluminum ingot into a vacuum melting furnace, heating it to 200-250°C, preheating it for 2-3 hours, heating it to 750-780°C, keeping it warm for 20 minutes, then adding beryllium, nickel and silicon, heating it to 1450-1550°C, vacuum melting to obtain a melt, adding a refining agent, keeping it warm and refining to obtain a mixed melt;

[0010] Step S3, casting the prepared mixed melt into a mold, first slowly cooling it, then rapidly cooling it, to obtain a beryllium aluminum alloy blank, and then degassing and hot isostatic pressing it to obtain a beryllium aluminum alloy with a high beryllium content.

[0011] The refining agent is prepared by the following steps:

[0012] The first step is to sequentially add kaolin powder and methyl cellulose to dolomite powder, add 35-45°C warm water, mix well and put into a molding machine to extrude round particles, then place in a muffle furnace at 250-300°C for calcination for 4-6 hours, cool to room temperature after calcination to obtain a porous matrix, and control the weight ratio of dolomite powder, kaolin powder and methyl cellulose to be 1: (0.3-0.5): (0.1-0.2);

[0013] In the first step, kaolin is used as a binder and methyl cellulose is used as a pore-forming agent, and the prepared dolomite porous matrix can increase its pores and thus increase its specific surface area;

[0014] The second step is to add oxalic acid, lithium hydroxide and boric acid into deionized water, stir at a constant speed and react for 4-6 hours. After the reaction is completed, add the porous matrix and continue stirring for 30-45 minutes to obtain a mixed solution. Then, the mixed solution is calcined at 100°C for 4 hours, and then calcined at 250°C for 4 hours to obtain a refining agent. The dosage ratio of oxalic acid, lithium hydroxide, boric acid, porous matrix and deionized water is controlled to be (1-2) mmol: (1-1.5) mmol: (2-3) mmol: (5-10) g: 50 mL.

[0015] In the second step, oxalic acid, lithium hydroxide and boric acid are used as raw materials, and lithium bis(oxalate borate) is generated in a porous matrix structure through two-step firing to obtain a refining agent. Lithium bis(oxalate borate) is first decomposed by heating to produce lithium carbonate and boron-containing oxides, and then decomposes to produce carbon dioxide. Carbon dioxide gas can degas during the melt purification process, reduce pores, and improve the refining effect. The introduction of boron-containing compounds can increase the generation efficiency of Fe-B compounds, improve the iron removal effect, and reduce the influence of iron elements introduced during smelting, casting, etc. on the alloy. After continuing to heat up, dolomite decomposes to produce magnesium oxide and carbon dioxide, etc. On the one hand, it can cooperate with the carbon dioxide produced by the decomposition of lithium bis(oxalate borate) to achieve repeated degassing and further improve the refining effect. On the other hand, the magnesium oxide produced can be used as an excellent refining agent to improve the refining effect.

[0016] Furthermore, the vacuum degree in the vacuum melting furnace in step S2 is 1×10 -3 Up to 1×10 -2 Pa.

[0017] Furthermore, in step S2, the refining agent can be added by evenly spreading it on the surface of the melt, pressing it into the melt, or spraying the refining agent into the melt using a jet machine.

[0018] Furthermore, the temperature of the degassing treatment in step S3 is 550-650°C, and the vacuum degree is ≤5×10 -3Pa, degassing time 3-5h; the temperature of hot isostatic pressing treatment is 600-700℃, the pressure is 120-130MPa, and the processing time is 3-5h.

[0019] Beneficial effects of the present invention:

[0020] The invention prepares a beryllium aluminum alloy with a high beryllium content. The refining effect can be significantly improved by adding a refining agent, and the beryllium aluminum alloy is endowed with more excellent comprehensive properties. The refining agent uses kaolin as a binder and methyl cellulose as a pore-forming agent. The calcined dolomite porous matrix can increase its pores, thereby increasing its specific surface area. Then, oxalic acid, lithium hydroxide and boric acid are used as raw materials, and lithium bis(oxalatoborate) is generated in the porous matrix structure through two-step firing to obtain the refining agent. The lithium bis(oxalatoborate) is first decomposed by heating to produce lithium carbonate and boron-containing oxides, and then decomposed to produce Carbon dioxide. Carbon dioxide gas can degas during the melt purification process, reduce pores and improve refining effects. The introduction of boron-containing compounds can increase the generation efficiency of Fe-B compounds, improve iron removal effects, and reduce the impact of iron elements introduced during smelting and casting on alloys. After further heating, dolomite decomposes to produce magnesium oxide and carbon dioxide. On the one hand, it can cooperate with the carbon dioxide produced by the decomposition of lithium bis(oxalatoborate) to achieve repeated degassing and further improve the refining effect. On the other hand, the magnesium oxide produced can be used as an excellent refining agent to improve the refining effect. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] Embodiment 1: A production process of a beryllium aluminum alloy with a high beryllium content, comprising the following steps:

[0023] Step S1, weighing the following raw materials in weight percentage: 65% beryllium, 3% nickel, 1% refining agent, 1% silicon, and the balance being aluminum and unavoidable impurities;

[0024] Step S2, adding the aluminum ingot into a vacuum melting furnace, heating it to 200°C, preheating it for 2 hours, heating it to 750°C, and keeping it warm for 20 minutes, then adding beryllium, nickel and silicon, heating it to 1450°C, vacuum melting to obtain a melt, adding a refining agent, keeping it warm and refining to obtain a mixed melt;

[0025] Step S3, casting the prepared mixed melt into a mold, first slowly cooling it, then rapidly cooling it, to obtain a beryllium aluminum alloy blank, and then degassing and hot isostatic pressing it to obtain a beryllium aluminum alloy with a high beryllium content.

[0026] The refining agent is prepared by the following steps:

[0027] The first step is to add kaolin powder (600-800 mesh, Shanghai Xiekang New Material Technology Co., Ltd.) and methyl cellulose (Shanghai Kaiyin Chemical Co., Ltd.) to dolomite powder (800-1250 mesh, Shanghai Xiekang New Material Technology Co., Ltd.), add 35°C warm water, mix well and add to a molding machine to extrude round particles, then place in a muffle furnace at 250°C for calcination for 4 hours, cool to room temperature after calcination to obtain a porous matrix, and control the weight ratio of dolomite powder, kaolin powder and methyl cellulose to be 1:0.3:0.1;

[0028] The second step is to add oxalic acid, lithium hydroxide and boric acid into deionized water, stir at a uniform speed and react for 4 hours. After the reaction, add the porous matrix and continue stirring for 30 minutes to obtain a mixed solution. Then, the mixed solution is fired at 100°C for 4 hours, and then fired at 250°C for 4 hours to obtain a refining agent. The dosage ratio of oxalic acid, lithium hydroxide, boric acid, porous matrix and deionized water is controlled to be 1mmol:1mmol:2mmol:5g:50mL.

[0029] The vacuum degree in the vacuum melting furnace in step S2 is 1×10 -3 Pa.

[0030] In step S2, the refining agent can be added by evenly spreading it on the surface of the melt, pressing it into the melt, or spraying the refining agent into the melt using a jet machine.

[0031] The degassing temperature in step S3 is 550°C and the vacuum degree is ≤5×10 -3 Pa, degassing time 3h; hot isostatic pressing temperature is 600℃, pressure is 120MPa, and processing time is 3h.

[0032] Embodiment 2: A production process of a beryllium aluminum alloy with a high beryllium content, comprising the following steps:

[0033] Step S1, weighing the following raw materials in weight percentage: 70% beryllium, 2.5% nickel, 1.5% refining agent, 0.05% silicon, and the balance being aluminum and unavoidable impurities;

[0034] Step S2, adding the aluminum ingot into a vacuum melting furnace, heating it to 220°C, preheating it for 2.5 hours, heating it to 760°C, keeping it warm for 20 minutes, then adding beryllium, nickel and silicon, heating it to 1500°C, vacuum melting to obtain a melt, adding a refining agent, keeping it warm and refining to obtain a mixed melt;

[0035] Step S3, casting the prepared mixed melt into a mold, first slowly cooling it, then rapidly cooling it, to obtain a beryllium aluminum alloy blank, and then degassing and hot isostatic pressing it to obtain a beryllium aluminum alloy with a high beryllium content.

[0036] The refining agent is prepared by the following steps:

[0037] The first step is to add kaolin powder (600-800 mesh, Shanghai Xiekang New Material Technology Co., Ltd.) and methyl cellulose (Shanghai Kaiyin Chemical Co., Ltd.) to dolomite powder (800-1250 mesh, Shanghai Xiekang New Material Technology Co., Ltd.), add 40°C warm water, mix well and add to a molding machine to extrude round particles, then place in a muffle furnace at 280°C and calcine for 5 hours. After calcination, cool to room temperature to obtain a porous matrix, and control the weight ratio of dolomite powder, kaolin powder and methyl cellulose to be 1:0.4:0.1;

[0038] The second step is to add oxalic acid, lithium hydroxide and boric acid into deionized water, stir at a uniform speed and react for 5 hours. After the reaction, add the porous matrix and continue stirring for 40 minutes to obtain a mixed solution. Then, the mixed solution is calcined at 100°C for 4 hours, and then calcined at 250°C for 4 hours to obtain a refining agent. The dosage ratio of oxalic acid, lithium hydroxide, boric acid, porous matrix and deionized water is controlled to be 1.5mmol:1.2mmol:2.5mmol:8g:50mL.

[0039] The vacuum degree in the vacuum melting furnace in step S2 is 1×10 -2 Pa.

[0040] In step S2, the refining agent can be added by evenly spreading it on the surface of the melt, pressing it into the melt, or spraying the refining agent into the melt using a jet machine.

[0041] The degassing temperature in step S3 is 600°C and the vacuum degree is ≤5×10 -3 Pa, degassing time 4h; the temperature of hot isostatic pressing treatment is 650℃, the pressure is 125MPa, and the treatment time is 4h.

[0042] Embodiment 3: A production process of a beryllium aluminum alloy with a high beryllium content, comprising the following steps:

[0043] Step S1, weighing the following raw materials in weight percentage: 75% beryllium, 2% nickel, 2% refining agent, 0.05% silicon, and the balance being aluminum and unavoidable impurities;

[0044] Step S2, adding the aluminum ingot into a vacuum melting furnace, heating it to 250°C, preheating it for 3 hours, heating it to 780°C, and keeping it warm for 20 minutes, then adding beryllium, nickel and silicon, heating it to 1550°C, vacuum melting to obtain a melt, adding a refining agent, keeping it warm and refining to obtain a mixed melt;

[0045] Step S3, casting the prepared mixed melt into a mold, first slowly cooling it, then rapidly cooling it, to obtain a beryllium aluminum alloy blank, and then degassing and hot isostatic pressing it to obtain a beryllium aluminum alloy with a high beryllium content.

[0046] The refining agent is prepared by the following steps:

[0047] The first step is to add kaolin powder (600-800 mesh, Shanghai Xiekang New Material Technology Co., Ltd.) and methyl cellulose (Shanghai Kaiyin Chemical Co., Ltd.) to dolomite powder (800-1250 mesh, Shanghai Xiekang New Material Technology Co., Ltd.), add 45°C warm water, mix well and add to a molding machine to extrude round particles, then place in a 300°C muffle furnace for calcination for 6 hours, cool to room temperature after calcination, and obtain a porous matrix, and control the weight ratio of dolomite powder, kaolin powder and methyl cellulose to be 1:0.5:0.2;

[0048] The second step is to add oxalic acid, lithium hydroxide and boric acid into deionized water, stir at a constant speed and react for 6 hours. After the reaction, add the porous matrix and continue stirring for 45 minutes to obtain a mixed solution. Then, the mixed solution is fired at 100°C for 4 hours and then at 250°C for 4 hours to obtain a refining agent. The dosage ratio of oxalic acid, lithium hydroxide, boric acid, porous matrix and deionized water is controlled to be 2mmol:1.5mmol:3mmol:10g:50mL.

[0049] The vacuum degree in the vacuum melting furnace in step S2 is 1×10 -3 Pa.

[0050] In step S2, the refining agent can be added by evenly spreading it on the surface of the melt, pressing it into the melt, or spraying the refining agent into the melt using a jet machine.

[0051] The degassing temperature in step S3 is 650°C and the vacuum degree is ≤5×10 -3 Pa, degassing time 5h; hot isostatic pressing temperature is 700℃, pressure is 130MPa, and processing time is 5h.

[0052] Comparative Example 1: Compared with Example 1, this comparative example uses a beryllium aluminum alloy refining agent (anhydrous magnesium chloride) produced by a commercially available company (Liaoning Yangchen Hongyu Metallurgical Materials Co., Ltd.) instead of the refining agent of the present invention.

[0053] Referring to the test method of GB / T 26063-2023, the properties of the high beryllium content beryllium aluminum alloys prepared in the above examples and comparative examples were tested, and the results are shown in Table 1 below:

[0054] Table 1

[0055]

[0056] It can be seen from Table 1 above that the high beryllium content beryllium aluminum alloys prepared in Examples 1 to 3 of the present invention have more excellent comprehensive properties.

[0057] The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A production process for high beryllium content beryllium aluminum alloy, characterized in that: The steps include: Step S1, weighing the following raw materials in weight percentage: 65-75% beryllium, 2-3% nickel, 1-2% refining agent, 0.05-1% silicon, and the balance being aluminum and unavoidable impurities; Step S2, adding the aluminum ingot into a vacuum melting furnace, heating it to 200-250°C, preheating it for 2-3 hours, heating it to 750-780°C, keeping it warm for 20 minutes, then adding beryllium, nickel and silicon, heating it to 1450-1550°C, vacuum melting to obtain a melt, adding a refining agent, keeping it warm and refining to obtain a mixed melt; Step S3, casting the obtained mixed melt into a mold, first cooling it slowly, then cooling it quickly, to obtain a beryllium aluminum alloy blank, and then degassing and hot isostatic pressing to obtain a beryllium aluminum alloy with a high beryllium content; The refining agent is prepared by the following steps: The first step is to add kaolin powder and methyl cellulose to dolomite powder in sequence, add 35-45°C warm water, mix well and put into a molding machine to extrude round particles, then place in a muffle furnace at 250-300°C for calcination for 4-6 hours, cool to room temperature after calcination to obtain a porous matrix; The second step is to add oxalic acid, lithium hydroxide and boric acid into deionized water, stir at a uniform speed and react for 4-6 hours. After the reaction, add the porous matrix and continue stirring for 30-45 minutes to obtain a mixed solution. Then, the mixed solution is calcined at 100°C for 4 hours, and then calcined at 250°C for 4 hours to obtain a refining agent.

2. The production process of a high beryllium content beryllium aluminum alloy according to claim 1, characterized in that: The vacuum degree in the vacuum melting furnace in step S2 is 1×10 -3 Up to 1×10 -2 Pa.

3. The production process of a high beryllium content beryllium aluminum alloy according to claim 1, characterized in that: In step S2, the refining agent is added by evenly spreading it on the surface of the melt, pressing it into the melt, or spraying the refining agent into the melt using a sprayer.

4. The production process of a beryllium aluminum alloy with a high beryllium content according to claim 1, characterized in that: The degassing temperature in step S3 is 550-650°C and the vacuum degree is ≤5×10 -3 Pa, degassing time 3-5h; the temperature of hot isostatic pressing treatment is 600-700℃, the pressure is 120-130MPa, and the processing time is 3-5h.

5. The production process of a beryllium aluminum alloy with a high beryllium content according to claim 1, characterized in that: In the first step, the weight ratio of dolomite powder, kaolin powder and methyl cellulose is controlled to be 1:(0.3-0.5):(0.1-0.2).

6. The production process of a high beryllium content beryllium aluminum alloy according to claim 1, characterized in that: In the second step, the dosage ratio of oxalic acid, lithium hydroxide, boric acid, porous matrix and deionized water is controlled to be (1-2) mmol: (1-1.5) mmol: (2-3) mmol: (5-10) g: 50 mL.

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