Production process of high-beryllium-content beryllium-aluminum alloy

Abstract

The application discloses a production process of a high-beryllium-content beryllium aluminum alloy and belongs to the technical field of beryllium-based aluminum alloy materials, and comprises the following steps: step S1, weighing the following weight percentage raw materials: 65-75% of beryllium, 2-3% of nickel, 1-2% of a refining agent, 0.05-1% of silicon, and the balance of aluminum and inevitable impurities; step S2, adding aluminum ingots into a vacuum melting furnace, heating to 200-250 DEG C, preheating for 2-3h, then heating to 750-780 DEG C, and keeping the temperature for 20 min, then adding beryllium, nickel and silicon, heating to 1450-1550 DEG C, vacuum melting, adding a refining agent, keeping the temperature for refining, and preparing a mixed melt; and step S3, pouring the prepared mixed melt into a mold, cooling, preparing a beryllium aluminum alloy blank, processing, and preparing the high-beryllium-content beryllium aluminum alloy; the refining effect can be obviously improved by adding the refining agent, and the beryllium aluminum alloy is endowed with more excellent comprehensive performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of beryllium-based aluminum alloy materials, and particularly relates to a production process of a high-beryllium-content beryllium aluminum alloy. BACKGROUND

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

[0003] The prior art improves the quality of the cast beryllium aluminum alloy by adding Ag, Mg, Ni, Co, Ge and other elements. However, the melting point difference between beryllium and aluminum is large (the melting point of beryllium is 1287℃, and the melting point of aluminum is 661℃), the mutual solubility is low, no intermetallic compound is generated, the solidification temperature range of the beryllium aluminum alloy is wide, and the prepared beryllium aluminum alloy has defects such as shrinkage holes and shrinkage porosity; in addition, aluminum is easy to accumulate at the interface of the beryllium aluminum alloy, and segregation of aluminum occurs, which leads to a decrease in various performances.

[0004] The beryllium aluminum alloy is cast at high temperature, and solid impurity particles are easy to be generated, and dross is generated on the surface of the melt, which leads to structural defects such as inclusions and pores, and causes a decrease in strength. Generally, a refining agent / slag remover needs to be added for treatment, and the refining agent system of the prior art cannot meet the manufacturing requirements of the high-beryllium-content beryllium aluminum alloy. SUMMARY

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

[0006] The purpose of the present application can be achieved by the following technical solutions:

[0007] A production process of a high-beryllium-content beryllium aluminum alloy, comprising the following steps:

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

[0009] Step S2, the aluminum ingot is added into a vacuum melting furnace, heated to 200-250℃, preheated for 2-3h, then heated to 750-780℃, and kept for 20min, then the beryllium, nickel and silicon are added, heated to 1450-1550℃, vacuum melting, the melt is prepared, the refining agent is added, and the mixed melt is prepared;

[0010] Step S3, the prepared mixed melt is cast in a mold, slow cooling is firstly performed, then rapid cooling is performed, the beryllium aluminum alloy blank is prepared, and then the high-beryllium-content beryllium aluminum alloy is prepared through degassing and hot isostatic pressing treatment.

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

[0012] The first step is to add kaolin powder and methyl cellulose to dolomite powder in sequence, add warm water at 35-45℃, mix uniformly, and then put into a molding machine to extrude circular particles, and then place in a muffle furnace at 250-300℃ for calcination for 4-6h, and then cool to room temperature to obtain a porous matrix, and the weight ratio of dolomite powder, kaolin powder and methyl cellulose is controlled 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, so that the prepared dolomite porous matrix can increase its porosity and further improve its specific surface area.

[0014] The second step is to add oxalic acid, lithium hydroxide and boric acid to deionized water, uniformly stir and react for 4-6h, then add the porous matrix and continue to stir for 30-45min to obtain a mixed solution, and then place the mixed solution in a 100℃ furnace for 4h, and then place it in a 250℃ furnace for 4h to obtain a refining agent, and the amount 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:50mL.

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

[0016] Further, the vacuum degree in the vacuum melting furnace in step S2 is 1x10 -3 to 1x10 -2 Pa.

[0017] Further, the refining agent in step S2 can be uniformly 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.

[0018] Further, the temperature of the degassing treatment in step S3 is 550-650℃, and the vacuum degree is ≤5x10 -3The degassing time is 3-5 hours; the hot isostatic pressing (HIP) treatment temperature is 600-700℃, the pressure is 120-130MPa, and the treatment time is 3-5 hours.

[0019] The beneficial effects of this invention are:

[0020] This invention prepares a high-beryllium-content beryllium-aluminum alloy. The addition of a refining agent significantly improves the refining effect, giving the beryllium-aluminum alloy superior overall properties. This refining agent uses kaolin as a binder and methylcellulose as a pore-forming agent. The calcined dolomite porous matrix increases its porosity, thereby improving its specific surface area. Then, using oxalic acid, lithium hydroxide, and boric acid as raw materials, a two-step calcination process generates lithium bis(oxalate-borate) in the porous matrix structure, thus producing the refining agent. Upon heating, lithium bis(oxalate-borate) first decomposes to produce lithium carbonate and boron-containing oxides, and then decomposes to produce… Carbon dioxide gas can degas the melt during the purification process, reduce porosity, and improve the refining effect. The introduction of boron compounds can improve the formation efficiency of Fe-B compounds, improve the iron removal effect, and reduce the impact of iron elements introduced during smelting and casting on the alloy. After further heating, dolomite decomposes to produce magnesium oxide and carbon dioxide, which can work synergistically 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 produced magnesium oxide can serve as an excellent refining agent to improve the refining effect. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Example 1: A production process for a high beryllium content beryllium aluminum alloy, comprising the following steps:

[0023] Step S1: Weigh the raw materials as follows by weight percentage: 65% beryllium, 3% nickel, 1% refining agent, 1% silicon, with the balance being aluminum and unavoidable impurities;

[0024] Step S2: Add aluminum ingots to a vacuum melting furnace, heat to 200°C, preheat for 2 hours, then heat to 750°C and hold for 20 minutes. Then add beryllium, nickel and silicon, heat to 1450°C, and vacuum melt to obtain a melt. Add refining agent, hold for heat and refine to obtain a mixed melt.

[0025] Step S3: The obtained mixed melt is cast into a mold, first cooled slowly, then cooled rapidly to obtain a beryllium aluminum alloy blank. After degassing and hot isostatic pressing, a high beryllium content beryllium aluminum alloy is obtained.

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

[0027] Step 1: Add kaolin powder (600-800 mesh, Shanghai Xiekang New Material Technology Co., Ltd.) and methylcellulose (Shanghai Kaiyin Chemical Co., Ltd.) sequentially to dolomite powder (800-1250 mesh). Add 35°C warm water, mix evenly, and then extrude the mixture into round particles in a molding machine. After that, calcine the particles in a muffle furnace at 250°C for 4 hours. After calcination, cool to room temperature to obtain a porous matrix. Control the weight ratio of dolomite powder, kaolin powder and methylcellulose to be 1:0.3:0.1.

[0028] Step 2: Add oxalic acid, lithium hydroxide, and boric acid to deionized water, stir at a constant speed and react for 4 hours. After the reaction is complete, add the porous matrix and continue stirring for 30 minutes to obtain a mixed solution. Then, place the mixed solution at 100°C for 4 hours and then at 250°C for 4 hours to obtain the refining agent. Control the ratio of oxalic acid, lithium hydroxide, boric acid, porous matrix, and deionized water to be 1 mmol: 1 mmol: 2 mmol: 5 g: 50 mL.

[0029] In step S2, the vacuum degree in the vacuum melting furnace is 1×10⁻⁶. -3 Pa.

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

[0031] The degassing process in step S3 is carried out at a temperature of 550℃ and a vacuum degree of ≤5×10⁻⁶. -3 Pa, degassing time 3h; hot isostatic pressing temperature 600℃, pressure 120MPa, processing time 3h.

[0032] Example 2: A production process for a high beryllium content beryllium aluminum alloy, comprising the following steps:

[0033] Step S1: Weigh the raw materials as follows by weight percentage: 70% beryllium, 2.5% nickel, 1.5% refining agent, 0.05% silicon, with the balance being aluminum and unavoidable impurities;

[0034] Step S2: Add aluminum ingots to a vacuum melting furnace, heat to 220°C, preheat for 2.5 hours, then heat to 760°C and hold for 20 minutes. Then add beryllium, nickel and silicon, heat to 1500°C, and vacuum melt to obtain a melt. Add refining agent, hold for refining, and obtain a mixed melt.

[0035] Step S3: The obtained mixed melt is cast into a mold, first cooled slowly, then cooled rapidly to obtain a beryllium aluminum alloy blank. After degassing and hot isostatic pressing, a high beryllium content beryllium aluminum alloy is obtained.

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

[0037] Step 1: Add kaolin powder (600-800 mesh, Shanghai Xiekang New Material Technology Co., Ltd.) and methylcellulose (Shanghai Kaiyin Chemical Co., Ltd.) sequentially to dolomite powder (800-1250 mesh). Add 40℃ warm water, mix evenly, and then extrude the mixture into round particles in a molding machine. After that, calcine the particles in a muffle furnace at 280℃ for 5 hours. After calcination, cool to room temperature to obtain a porous matrix. Control the weight ratio of dolomite powder, kaolin powder and methylcellulose to be 1:0.4:0.1.

[0038] Step 2: Add oxalic acid, lithium hydroxide, and boric acid to deionized water, stir at a constant speed and react for 5 hours. After the reaction is complete, add the porous matrix and continue stirring for 40 minutes to obtain a mixed solution. Then, place the mixed solution at 100°C for 4 hours and then at 250°C for 4 hours to obtain the refining agent. Control the ratio of oxalic acid, lithium hydroxide, boric acid, porous matrix, and deionized water to be 1.5 mmol:1.2 mmol:2.5 mmol:8 g:50 mL.

[0039] In step S2, the vacuum degree in the vacuum melting furnace is 1×10⁻⁶. -2 Pa.

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

[0041] The degassing process in step S3 is carried out at a temperature of 600℃ and a vacuum degree of ≤5×10⁻⁶. -3 Pa, degassing time 4h; hot isostatic pressing temperature 650℃, pressure 125MPa, processing time 4h.

[0042] Example 3: A production process for a high beryllium content beryllium aluminum alloy, comprising the following steps:

[0043] Step S1: Weigh the raw materials as follows by weight percentage: 75% beryllium, 2% nickel, 2% refining agent, 0.05% silicon, with the balance being aluminum and unavoidable impurities;

[0044] Step S2: Add aluminum ingots to a vacuum melting furnace, heat to 250°C, preheat for 3 hours, then heat to 780°C and hold for 20 minutes. Then add beryllium, nickel and silicon, heat to 1550°C, and vacuum melt to obtain a melt. Add refining agent, hold for heat and refine to obtain a mixed melt.

[0045] Step S3: The obtained mixed melt is cast into a mold, first cooled slowly, then cooled rapidly to obtain a beryllium aluminum alloy blank. After degassing and hot isostatic pressing, a high beryllium content beryllium aluminum alloy is obtained.

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

[0047] Step 1: Add kaolin powder (600-800 mesh, Shanghai Xiekang New Material Technology Co., Ltd.) and methylcellulose (Shanghai Kaiyin Chemical Co., Ltd.) sequentially to dolomite powder (800-1250 mesh). Add 45℃ warm water, mix evenly, and then extrude the mixture into round particles in a molding machine. After that, calcine the particles in a muffle furnace at 300℃ for 6 hours. After calcination, cool to room temperature to obtain a porous matrix. Control the weight ratio of dolomite powder, kaolin powder and methylcellulose to be 1:0.5:0.2.

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

[0049] In step S2, the vacuum degree in the vacuum melting furnace is 1×10⁻⁶. -3 Pa.

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

[0051] The degassing process in step S3 is carried out at a temperature of 650℃ and a vacuum degree of ≤5×10⁻⁶. -3 Pa, degassing time 5h; hot isostatic pressing temperature 700℃, pressure 130MPa, processing time 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] The properties of the high beryllium content beryllium aluminum alloys prepared in the above examples and comparative examples were tested according to the test methods of GB / T 26063-2023. The results are shown in Table 1 below:

[0054] Table 1

[0055]

[0056] As can be seen from Table 1 above, the high beryllium content beryllium aluminum alloys prepared in Examples 1-3 of the present invention have superior comprehensive properties.

[0057] The above description is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined in the claims, they should all fall within the protection scope of the present invention.

Claims

1. A production process for a high beryllium content beryllium aluminum alloy, characterized in that, Includes the following steps: Step S1: Weigh the following raw materials by weight percentage: 65-75% beryllium, 2-3% nickel, 1-2 parts refining agent, 0.05-1% silicon, with the balance being aluminum and unavoidable impurities; Step S2: Add aluminum ingots to a vacuum melting furnace, heat to 200-250℃, preheat for 2-3 hours, then heat to 750-780℃ and hold for 20 minutes. Then add beryllium, nickel and silicon, heat to 1450-1550℃, and vacuum melt to obtain a melt. Add refining agent, hold for refining, and obtain a mixed melt. In step S2, the refining agent is added by spreading it evenly on the surface of the melt and pressing it into the melt, or by using a jetting machine to spray the refining agent into the melt. Step S3: The prepared mixed melt is poured into a mold, first cooled slowly, then cooled rapidly to obtain a beryllium aluminum alloy blank. After degassing and hot isostatic pressing, a high beryllium content beryllium aluminum alloy is obtained. The refining agent is prepared through the following steps: Step 1: Add kaolin powder and methylcellulose to dolomite powder in sequence, add warm water at 35-45℃, mix evenly, and then put it into a molding machine to extrude round particles. Then place it in a muffle furnace at 250-300℃ for calcination for 4-6 hours. After calcination, cool to room temperature to obtain a porous matrix. The second step involves adding oxalic acid, lithium hydroxide, and boric acid to deionized water, stirring at a constant speed, and reacting for 4-6 hours. After the reaction is complete, a porous matrix is ​​added, and stirring is continued for 30-45 minutes to obtain a mixed solution. The mixed solution is then calcined at 100°C for 4 hours, followed by calcination at 250°C for 4 hours to obtain the refining agent.

2. The production process of a high beryllium content beryllium aluminum alloy according to claim 1, characterized in that, In step S2, the vacuum degree in the vacuum melting furnace is 1×10⁻⁶. -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, The degassing process in step S3 is carried out at a temperature of 550-650℃ and a vacuum degree of ≤5×10⁻⁶. -3 The degassing time is 3-5 hours; the hot isostatic pressing (HIP) treatment temperature is 600-700℃, the pressure is 120-130MPa, and the treatment time is 3-5 hours.

4. The production process of a high beryllium content beryllium aluminum alloy according to claim 1, characterized in that, In the first step, the weight ratio of dolomite powder, kaolin powder and methylcellulose is controlled to be 1:0.3-0.5:0.1-0.

2.

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

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