High-performance aluminum alloy for aluminum frame of electrolytic cell and preparation method of high-performance aluminum alloy

Abstract

The invention belongs to the technical field of aluminum alloy manufacturing, and provides a high-performance aluminum alloy for an aluminum frame of an electrolytic cell, which comprises the following components: 5-8% of Si, 0.5-3.0% of Be, 0.5-2.5% of Mn, 0.5-3.0% of Li, 0.01-0.07% of a refiner, less than or equal to 0.15% of impurities and the balance of A1, alloy elements Be, Li and Mn are added into a high-fluidity Al-Si alloy, a refiner is added to refine grains to improve the modulus and strength of the alloy, meanwhile, the modes of smelting, solution annealing, aging treatment and the like are adopted for coordinated regulation and control, and finally the aluminum frame alloy for the electrolytic bath with high heat resistance, high modulus and high corrosion resistance is obtained. The continuous service life of the electrolytic bath can be prolonged; the production efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy manufacturing technology, and in particular to a high-performance aluminum alloy for electrolytic cell aluminum frames and its preparation method. Background Technology

[0002] In existing continuous anode aluminum electrolytic cells, the aluminum frame is a key component, and its performance directly affects the cell's service life and production efficiency. Aluminum electrolytic cells typically operate in high-temperature (approximately 300°C) and highly corrosive environments. The electrolysis process generates large amounts of corrosive gases such as fluorides and oxides, as well as molten salts, placing extremely high demands on the mechanical properties and corrosion resistance of the aluminum frame material. However, traditional aluminum frame materials, due to their low strength and poor corrosion resistance, struggle to meet these demanding operating conditions, leading to a shortened cell lifespan, increased maintenance costs, and even reduced production efficiency.

[0003] Currently, the performance of commonly used aluminum frame materials is mainly improved through alloying or surface treatment. Alloying improves the material's strength, hardness, and corrosion resistance by adding other elements (such as copper, magnesium, silicon, zinc, etc.) to the aluminum matrix. However, while alloying can improve material performance to some extent, its effect is limited, especially in high-temperature and highly corrosive environments, where the performance of alloyed materials still struggles to meet long-term usage requirements. Furthermore, alloyed materials are expensive and require complex processing, increasing production costs. Another commonly used method is surface treatment, such as anodizing, electroplating, and spraying. Surface treatment can form a protective film on the aluminum frame surface, thereby improving its corrosion resistance and wear resistance. However, the protective layer from surface treatment is usually thin and prone to peeling or failure in high-temperature and highly corrosive environments, leading to decreased durability of the aluminum frame. In addition, surface treatment processes are complex and require regular maintenance and re-treatment, increasing production complexity and costs.

[0004] Besides alloying and surface treatment, recent studies have also attempted to improve the performance of aluminum frames through composite materials or nanotechnology. For example, adding reinforcing phases such as ceramic particles or carbon fibers to the aluminum matrix can significantly improve the material's strength and corrosion resistance. However, while these methods improve material performance to some extent, their preparation processes are complex and costly, and they still face many challenges in practical applications, such as the interfacial bonding between the reinforcing phase and the matrix, and the uniformity of the material.

[0005] In summary, existing aluminum frame materials still have many shortcomings in terms of strength, corrosion resistance, cost, and manufacturing processes, making it difficult to meet the long-term use requirements of continuous anodic electrolytic cells in high-temperature and highly corrosive environments. Therefore, how to improve the heat resistance, corrosion resistance, and extend the continuous production service life of electrolytic cells of aluminum frame alloy materials has become an urgent technical problem to be solved. Summary of the Invention

[0006] The purpose of this invention is to provide a high-performance aluminum alloy for electrolytic cell frames and its preparation method. By adding alloying elements Be, Li, and Mn to a high-fluidity Al-Si alloy and adding a grain refiner to refine the grains and improve the alloy modulus and strength, and by using smelting, solution annealing, and aging treatment to coordinate and control the process, a high-heat-resistant, high-modulus, and high-corrosion-resistant aluminum alloy for electrolytic cells is finally obtained, which can extend the continuous service life of electrolytic cells and improve production efficiency.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0008] A high-performance aluminum alloy for use in electrolytic cell frames is characterized by comprising the following components by mass percentage: Si 5%–8%, Be 0.5%–3.0%, Mn 0.5%–2.5%, Li 0.5%–3.0%, refining agent 0.01%–0.07%, total impurities ≤0.15%, and the balance being Al.

[0009] The refining agent includes one or more of super aluminum titanium boron, alumina fiber, and carbon fiber.

[0010] Preferably, the refining agent is super aluminum-titanium-boron, and the aluminum-titanium-boron component is in the form of AlTi5B. 0.1 and / or AlTi5B 0.2 .

[0011] Preferably, the aluminum alloy has an elastic modulus ≥80GPa, a tensile strength ≥280MPa after 100 hours of heat exposure at 300℃, an elongation ≥8%, and an intergranular corrosion resistance level of 1 to 2.

[0012] This invention also provides a method for preparing the above-mentioned high-performance aluminum alloy, comprising the following steps:

[0013] 1) Weigh the raw materials according to the proportion and melt them to obtain an aluminum alloy solution. The raw materials include aluminum alloy, aluminum-silicon master alloy, lithium alloy, aluminum-manganese master alloy, aluminum-beryllium master alloy and / or aluminum-lithium master alloy.

[0014] 2) Degas and remove slag from the aluminum alloy solution, add a refining agent and mix to obtain molten aluminum;

[0015] 3) After cooling the molten aluminum to room temperature, pour it into a mold to form an aluminum frame;

[0016] 4) The aluminum frame is subjected to solution treatment and aging treatment in sequence to obtain a high-performance aluminum alloy for the aluminum frame of the electrolytic cell.

[0017] Preferably, in step 1), the order of adding the smelting raw materials is to add the intermediate alloy first, followed by the addition of the single-element alloy.

[0018] Preferably, the melting temperature in step 1) is 700-750°C, and the melting heating rate is 5-10°C / min.

[0019] Preferably, step 2) is carried out under mechanical stirring conditions, and the stirring speed is 200-400 r·min. -1 The stirring time is 10 to 30 minutes.

[0020] Preferably, the mold in step 3) needs to be preheated to 200-300°C.

[0021] Preferably, step 4) solution treatment includes a first solution treatment and a second solution treatment, wherein the first solution treatment temperature is 470-500℃ and the first solution treatment holding time is 6-10h; the second solution treatment temperature is 500-540℃ and the second solution treatment holding time is 8-10h.

[0022] Preferably, step 4) aging treatment includes a first aging treatment and a second aging treatment. The temperature of the first aging treatment is 120-150℃, and the holding time of the first aging treatment is 10-16h. The temperature of the second aging treatment is 160-200℃, and the holding time of the second aging treatment is 2-6h.

[0023] Beneficial effects:

[0024] 1. This invention addresses the extreme service conditions of aluminum frames in continuous anodic electrolytic cells. Based on a multi-objective design strategy, it proposes a high-performance aluminum alloy for electrolytic cell frames. By adding alloying elements such as Be, Li, Mg, and Mn to a high-fluidity Al-Si alloy, and simultaneously introducing a grain refiner, a dual effect of significant grain refinement and dispersion strengthening is achieved. The combined effect of grain refinement and dispersed particle distribution significantly improves the alloy's room temperature and high temperature elastic modulus, yield strength, and tensile strength. Example results show that the aluminum alloy has a maximum intergranular corrosion resistance level of 1; an elastic modulus ≥80 GPa; a tensile strength ≥280 MPa after 100 hours of heat exposure at 300℃; and an elongation ≥8%, all significantly higher than traditional aluminum frame materials used in continuous anodic electrolytic cells.

[0025] 2. The high-performance aluminum alloy for electrolytic cell frames prepared by this invention can achieve lightweighting and cost control while maintaining or improving the mechanical and corrosion resistance properties of the alloy material. It is feasible for large-scale industrial production, with significant economic and social benefits. It is widely applicable to aluminum alloy components that serve in high-temperature and highly corrosive environments, such as aluminum electrolytic cell frames, high-temperature chemical reactors, aero-engines, and automotive powertrains.

[0026] 3. The multi-stage solution and aging treatment scheme in the aluminum alloy preparation method provided by this invention can precipitate highly heat-resistant nanophases in situ within the grains, inhibit high-temperature softening and grain growth, and ensure that the aluminum frame maintains dimensional and mechanical property stability during long-term service at ≥300℃. Furthermore, the multi-stage solution-aging treatment of this invention can further regulate the morphology and distribution of grain boundary precipitates, reduce grain boundary electric dipole, significantly improve resistance to intergranular corrosion and salt spray corrosion, and extend the service life of the electrolytic cell.

[0027] 4. The aluminum alloy preparation method provided by the present invention achieves grain refinement by optimizing the alloy composition. Grain refinement further increases the number of grain boundaries and provides more atomic diffusion channels, thereby accelerating the dissolution rate and supersaturation of strengthening elements in the matrix, thus shortening the solution treatment time or reducing the treatment temperature, reducing the process requirements of solution treatment, and improving the production efficiency of aluminum alloy production. Detailed Implementation

[0028] This invention provides a high-performance aluminum alloy for use in electrolytic cell aluminum frames, comprising the following components by mass percentage: Si 5%–8%, Be 0.5%–3.0%, Mn 0.5%–2.5%, Li 0.5%–3.0%, refining agent 0.01%–0.07%, total impurities ≤0.15%, and the balance being Al.

[0029] This invention does not impose any special limitation on the specific source of raw materials for the above alloy components. Commercially available products and known alloys familiar to those skilled in the art can be used. This invention prefers alloy raw materials with low impurity content. In this invention, the raw materials are preferably aluminum alloys, aluminum-silicon master alloys, lithium alloys, aluminum-manganese master alloys, and aluminum-beryllium master alloys.

[0030] This invention provides a high-performance aluminum alloy for use in electrolytic cell aluminum frames, comprising 5% to 8% Si by mass percentage, preferably 6% to 7%. In this invention, Si is used as a basic element, mainly to increase the fluidity of the aluminum alloy, reduce the shrinkage rate, and decrease the tendency to hot cracking.

[0031] This invention provides a high-performance aluminum alloy for use in electrolytic cell aluminum frames, comprising, by mass percentage, 0.5% to 3.0% Be, preferably 1.0% to 2.0%, and more preferably 1.5%. In this invention, the addition of Be not only increases the elastic modulus of the aluminum alloy but also protects the melt to reduce alloy oxidation, further reducing the oxygen content of the alloy to improve the performance of the alloy material. At the same time, it can also reduce the formation of oxygen inclusions during casting, which is beneficial to improving the surface quality of the casting.

[0032] This invention provides a high-performance aluminum alloy for use in electrolytic cell aluminum frames, comprising, by mass percentage, 0.5% to 2.5% Mn, preferably 1.0% to 2.0%, and more preferably 1.5%. The addition of Mn and heat treatment in this invention can form fine high-modulus and heat-resistant compound phases such as Al4Mn and Al6Mn in the alloy, thereby improving the elastic modulus and heat resistance of the matrix alloy.

[0033] This invention provides a high-performance aluminum alloy for use in electrolytic cell aluminum frames, comprising, by mass percentage, 0.5% to 3.0% Li, preferably 1.0% to 2.0%, and more preferably 1.5%; the addition of Li in this invention enables the aluminum alloy to precipitate a high-modulus Al3Li phase during subsequent heat treatment.

[0034] This invention provides a high-performance aluminum alloy for use in electrolytic cell aluminum frames, wherein the total amount of impurities in the alloy is ≤0.15% by mass, and the content of a single impurity in the alloy is ≤0.05%.

[0035] This invention provides a high-performance aluminum alloy for an aluminum frame of an electrolytic cell, comprising, by weight percentage, 0.01% to 0.07% refining agent, preferably 0.03% to 0.06%, and more preferably 0.05%; in this invention, the refining agent comprises one or more of super aluminum titanium boron, alumina fiber, and carbon fiber.

[0036] In this invention, the refining agent is preferably a super aluminum-titanium-boron alloy, wherein the aluminum-titanium-boron alloy is in the form of AlTi5B. 0.1 and AlTi5B 0.2 In this invention, Ti in super aluminum-titanium-boron alloys... x B y It is evenly and diffusely distributed, not easily aggregated, and the tendency to aggregate does not increase over time; Ti x B y The alloy particles have high activity and high nucleation rate, strong ability to control grain refinement, and fast effect. They can significantly improve the elastic modulus and corrosion resistance of aluminum alloys. Compared with ordinary grain refiners, super aluminum-titanium-boron contains more than 30 times more nucleating particles. To achieve the same grain size, the amount of grain refiner required is greatly reduced.

[0037] The high-performance aluminum alloy for electrolytic cell frames provided by this invention has an elastic modulus ≥80GPa, a tensile strength ≥280MPa after 100 hours of heat exposure at 300℃, an elongation ≥8%, and an intergranular corrosion resistance level of 1 to 2.

[0038] This invention also provides a method for preparing the above-mentioned high-performance aluminum alloy for the aluminum frame of the electrolytic cell, comprising the following steps:

[0039] 1) Weigh the raw materials according to the alloy ratio and melt them to obtain an aluminum alloy solution. The raw materials include aluminum alloy, aluminum-silicon master alloy, lithium alloy, aluminum-manganese master alloy, aluminum-beryllium master alloy and / or aluminum-lithium master alloy.

[0040] 2) Degas and remove slag from the aluminum alloy solution, add a refining agent and mix to obtain molten aluminum;

[0041] 3) After cooling the molten aluminum to room temperature, pour it into a mold to form an aluminum frame;

[0042] 4) The aluminum frame is subjected to solution treatment and aging treatment in sequence to obtain a high-performance aluminum alloy for the aluminum frame of the electrolytic cell.

[0043] This invention involves weighing raw materials according to alloy ratios and smelting them to obtain an aluminum alloy solution.

[0044] In this invention, the raw materials include aluminum alloy, aluminum-silicon master alloy, lithium alloy, aluminum-manganese master alloy, aluminum-beryllium master alloy and / or aluminum-lithium master alloy; the preferred order of adding the smelting raw materials in this invention is to add the master alloy first, followed by the elemental alloy; the elemental alloy is an aluminum-lithium alloy.

[0045] In this invention, the preferred melting temperature is 700–750°C, and the preferred heating rate before melting is 5–10°C / min. This invention does not have strict requirements on the melting time, as long as the raw materials can be completely melted. In this invention, the melting process, based on different pressures, is preferably vacuum melting, atmospheric melting, or atmospheric pressure melting.

[0046] After obtaining the aluminum alloy solution, the present invention degasses and removes slag from the aluminum alloy solution, and adds a refining agent to mix and obtain aluminum melt.

[0047] In this invention, the degassing and slag removal are preferably carried out by introducing an inert gas into the aluminum alloy solution. The inert gas is preferably argon, helium, or nitrogen. In this invention, an inert gas is introduced into the molten aluminum alloy solution. The argon gas rises in the melt as bubbles, stirring the melt and causing gases and inclusions in the melt to be carried to the melt surface. Inclusions in the aluminum alloy liquid (such as alumina, non-metallic particles, etc.) typically have low density and easily adhere to the surface of the argon gas bubbles. During the bubble rise, the inclusions are carried to the melt surface and removed. The inert gas also protects the melt, preventing it from undergoing oxidation with oxygen in the air at high temperatures.

[0048] In this invention, the flow rate of the inert gas is preferably 0.1 to 0.3 m³ / h. 3 / h, the pressure of the inert gas is preferably 0.2 to 0.5 MPa; the present invention controls the bubble diameter to 1 to 3 mm by precisely controlling the flow rate and pressure of the introduced gas. Larger bubbles can not only carry impurities and gas more effectively, but the control of pressure and flow rate can also reduce the probability of bubble rupture during the rising process.

[0049] In this invention, the mixing is preferably carried out under mechanical stirring conditions, and the stirring speed is preferably 200-400 r·min. -1 The stirring time is preferably 10 to 30 minutes.

[0050] After obtaining the aluminum melt, the present invention cools the aluminum melt to room temperature and then pours it into a mold to form an aluminum frame.

[0051] In this invention, the cooling rate is preferably 10–50 °C / min; the mold is preferably preheated before pouring, and the preheating temperature is 200–300 °C. This invention does not impose any special limitations on the mold forming method; conventional processes in the art can be used.

[0052] Finally, the present invention performs solution treatment and aging treatment on the aluminum frame in sequence to obtain a high-performance aluminum alloy for electrolytic cell aluminum frame.

[0053] In this invention, the solution treatment process includes: heating the aluminum frame to the solution temperature and holding it at that temperature to allow the strengthening elements in the alloy to fully dissolve, forming a supersaturated solid solution, and then rapidly cooling it to room temperature. This solution treatment eliminates micro-segregation in the alloy, relieves stress generated by hot and cold working, promotes recrystallization of the alloy, and significantly improves the high-temperature creep resistance of the aluminum alloy.

[0054] In this invention, the solution treatment preferably includes a first solution treatment and a second solution treatment. The first solution treatment temperature is 470–500°C, and the first solution treatment holding time is 6–10 h. The second solution treatment temperature is 500–540°C, and the second solution treatment holding time is 8–10 h. In this invention, the heating rates of the first and second solution treatments are independently preferably 5–10°C / min. In this invention, the cooling rate of the solution treatment to room temperature is preferably 1–10°C / s.

[0055] In this invention, the aging treatment process includes: reheating the solution-treated aluminum frame to the aging temperature and holding it at that temperature to allow supersaturated strengthening elements to precipitate from the solid solution, forming fine, dispersed strengthening phases, followed by cooling to room temperature. This invention employs aging treatment, which can significantly improve the tensile strength and yield strength of aluminum alloy materials, meeting the high mechanical performance requirements of aluminum frames in electrolytic cells. In this invention, the aging treatment includes a first aging treatment and a second aging treatment. The first aging treatment temperature is 120–150°C, and the holding time is 10–16 hours. The second aging treatment temperature is 160–200°C, and the holding time is 2–6 hours.

[0056] This invention employs a multi-stage solution treatment plus aging process, which, compared to a one-time treatment process, can precipitate highly heat-resistant nanophases in situ within the crystals, suppressing high-temperature softening and grain growth, and ensuring the mechanical stability of the aluminum frame during long-term service at ≥300℃.

[0057] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0058] Example 1

[0059] The aluminum frame of the electrolytic cell is composed of high-performance aluminum alloy, with a mass percentage of 5% Si to 0.2% Be.

[0060] ~1% Mn ~0.5% Li ~Al balance, 0.01% super aluminum titanium boron (AlTi5B) 0.1 and AlTi5B 0.2 ).

[0061] Preparation method:

[0062] 1) Calculate the required raw materials according to the alloy composition ratio, and melt aluminum-silicon master alloy, aluminum-manganese master alloy, aluminum-beryllium master alloy, aluminum-lithium master alloy and aluminum and lithium in sequence under vacuum conditions of 700℃ to obtain aluminum alloy solution.

[0063] 2) Argon gas is introduced into the aluminum alloy solution for composite degassing and slag removal; a finer agent, super aluminum-titanium-boron, is added, and mechanical stirring is used to ensure that the finer agent is evenly distributed in the aluminum melt, with a stirring speed of 200 r·min. -1 The time is 10 minutes;

[0064] 3) After standing and cooling to room temperature, pour the mixture into a mold to form an aluminum frame.

[0065] 4) The aluminum frame is subjected to solution treatment and aging treatment at a heating rate of 10℃ / min. The solution treatment process is as follows: the first stage solution temperature is 480℃ and the holding time is 10h; the second stage solution temperature is 520℃ and the holding time is 8h. The aging treatment process is as follows: the first stage aging temperature is 130℃ and the holding time is 12h; the second stage aging temperature is 180℃ and the holding time is 4h, thus obtaining a high-performance aluminum alloy for the aluminum frame of the electrolytic cell.

[0066] Example 2

[0067] The high-performance aluminum alloy used for the electrolytic cell frame has the following composition by weight percentage:

[0068] 6.5% Si ~ 1.5% Be ~ 1.5% Mn ~ 1.5% Li ~ Balance Al, 0.01% Super Aluminum Titanium Boron (AlTi5B) 0.1 and AlTi5B 0.2 ).

[0069] Preparation method:

[0070] 1) Calculate the required raw materials according to the alloy composition ratio, and melt aluminum-silicon master alloy, aluminum-manganese master alloy, aluminum-beryllium master alloy, aluminum-lithium master alloy and aluminum and lithium in sequence under vacuum conditions of 750℃ to obtain aluminum alloy solution.

[0071] 2) Helium gas is introduced into the aluminum alloy molten metal for composite degassing and slag removal; a finer agent, super aluminum-titanium-boron, is added, and mechanical stirring is used to ensure that the finer agent is evenly distributed in the aluminum melt, with a stirring speed of 200 r·min. -1 The time is 10 minutes;

[0072] 3) After degassing and slag removal, the aluminum frame is poured into a mold after being allowed to cool to room temperature.

[0073] 4) The aluminum frame is subjected to solution treatment and aging treatment at a heating rate of 10℃ / min. The solution treatment process is as follows: the first stage solution temperature is 480℃ and the holding time is 10h; the second stage solution temperature is 520℃ and the holding time is 8h. The aging treatment process is as follows: the first stage aging temperature is 130℃ and the holding time is 12h; the second stage aging temperature is 180℃ and the holding time is 4h, thus obtaining a high-performance aluminum alloy for the aluminum frame of the electrolytic cell.

[0074] Example 3

[0075] The aluminum frame of the electrolytic cell is composed of high-performance aluminum alloy, by mass percentage: 6.5% Si ~ 1.5% Be ~ 1.5% Mn ~ 1.5% Li ~ Al balance, 0.03% super aluminum titanium boron (AlTi5B). 0.1 and AlTi5B 0.2 ).

[0076] Preparation method:

[0077] 1) Calculate the required raw materials according to the alloy composition ratio, and melt aluminum-silicon master alloy, aluminum-manganese master alloy, aluminum-beryllium master alloy, aluminum-lithium master alloy and aluminum and lithium in sequence under vacuum conditions of 700℃ to obtain aluminum alloy solution.

[0078] 2) Argon gas is introduced into the aluminum alloy solution for composite degassing and slag removal; a finer agent, super aluminum-titanium-boron, is added, and mechanical stirring is used to ensure that the finer agent is evenly distributed in the aluminum melt, with a stirring speed of 200 r·min. -1 The time is 10 minutes;

[0079] 3) After standing and cooling to room temperature, pour the mixture into a mold to form an aluminum frame.

[0080] 4) The aluminum frame is subjected to solution treatment and aging treatment at a heating rate of 10℃ / min. The solution treatment process is as follows: the first stage solution temperature is 480℃ and the holding time is 10h; the second stage solution temperature is 520℃ and the holding time is 8h. The aging treatment process is as follows: the first stage aging temperature is 130℃ and the holding time is 12h; the second stage aging temperature is 180℃ and the holding time is 4h, thus obtaining a high-performance aluminum alloy for the electrolytic cell frame.

[0081] Example 4

[0082] The aluminum frame of the electrolytic cell is composed of high-performance aluminum alloy, by mass percentage: 6.5% Si ~ 1.5% Be ~ 1.5% Mn ~ 1.5% Li ~ Al balance, 0.05% super aluminum titanium boron (AlTi5B). 0.1 and AlTi5B 0.2 ).

[0083] Preparation method:

[0084] 1) Calculate the required raw materials according to the alloy composition ratio, and melt aluminum-silicon master alloy, aluminum-manganese master alloy, aluminum-beryllium master alloy, aluminum-lithium master alloy and aluminum and lithium in sequence under vacuum conditions of 700℃ to obtain aluminum alloy solution.

[0085] 2) Argon gas is introduced into the aluminum alloy solution for composite degassing and slag removal; a finer agent, super aluminum-titanium-boron, is added, and mechanical stirring is used to ensure that the finer agent is evenly distributed in the aluminum melt, with a stirring speed of 200 r·min. -1 The time is 10 minutes;

[0086] 3) After standing and cooling to room temperature, pour the mixture into a mold to form an aluminum frame.

[0087] 4) The aluminum frame is subjected to solution treatment and aging treatment at a heating rate of 10℃ / min. The solution treatment process is as follows: the first stage solution temperature is 480℃ and the holding time is 10h; the second stage solution temperature is 520℃ and the holding time is 8h. The aging treatment process is as follows: the first stage aging temperature is 130℃ and the holding time is 12h; the second stage aging temperature is 180℃ and the holding time is 4h, thus obtaining a high-performance aluminum alloy for the aluminum frame of the electrolytic cell.

[0088] Example 5

[0089] The aluminum frame of the electrolytic cell is composed of high-performance aluminum alloy, by mass percentage: 6.5% Si ~ 1.5% Be ~ 1.5% Mn ~ 1.5% Li ~ Al balance, 0.07% super aluminum titanium boron (AlTi5B) 0.1 and AlTi5B 0.2 ).

[0090] Preparation method:

[0091] 1) Calculate the required raw materials according to the alloy composition ratio, and melt aluminum-silicon master alloy, aluminum-manganese master alloy, aluminum-beryllium master alloy, aluminum-lithium master alloy and aluminum and lithium in sequence under vacuum conditions of 700℃ to obtain aluminum alloy solution.

[0092] 2) Argon gas is introduced into the aluminum alloy solution for composite degassing and slag removal; a finer agent, super aluminum-titanium-boron, is added, and mechanical stirring is used to ensure that the finer agent is evenly distributed in the aluminum melt, with a stirring speed of 200 r·min. -1 The time is 10 minutes;

[0093] 3) After standing and cooling to room temperature, pour the mixture into a mold to form an aluminum frame.

[0094] 4) The aluminum frame is subjected to solution treatment and aging treatment. The solution treatment process is as follows: the first stage solution temperature is 480℃ and the holding time is 10h; the second stage solution temperature is 520℃ and the holding time is 8h. The aging treatment process is as follows: the first stage aging temperature is 130℃ and the holding time is 12h; the second stage aging temperature is 180℃ and the holding time is 4h, to obtain a high-performance aluminum alloy for the aluminum frame of the electrolytic cell.

[0095] Example 6

[0096] The aluminum frame of the electrolytic cell is composed of high-performance aluminum alloy, with a mass percentage of 7% Si to 2.0% Be.

[0097] ~2.0% Mn ~2.0% Li ~Al balance, 0.05% super aluminum titanium boron (AlTi5B) 0.1 and AlTi5B 0.2 ).

[0098] Preparation method:

[0099] 1) Calculate the required raw materials according to the alloy composition ratio, and melt aluminum-silicon master alloy, aluminum-manganese master alloy, aluminum-beryllium master alloy, aluminum-lithium master alloy and aluminum and lithium in sequence under vacuum conditions of 700℃ to obtain aluminum alloy solution.

[0100] 2) Argon gas is introduced into the aluminum alloy solution for composite degassing and slag removal; a finer agent, super aluminum-titanium-boron, is added, and mechanical stirring is used to ensure that the finer agent is evenly distributed in the aluminum melt, with a stirring speed of 200 r·min. -1 The time is 10 minutes;

[0101] 3) After standing and cooling to room temperature, pour the mixture into a mold to form an aluminum frame.

[0102] 4) The aluminum frame is subjected to solution treatment and aging treatment at a heating rate of 10℃ / min. The solution treatment process is as follows: the first stage solution temperature is 480℃ and the holding time is 10h; the second stage solution temperature is 520℃ and the holding time is 8h. The aging treatment process is as follows: the first stage aging temperature is 130℃ and the holding time is 12h; the second stage aging temperature is 180℃ and the holding time is 4h, thus obtaining a high-performance aluminum alloy for the aluminum frame of the electrolytic cell.

[0103] Example 7

[0104] The aluminum frame of the electrolytic cell is composed of high-performance aluminum alloy, with a mass percentage of 8% Si to 3.0% Be.

[0105] ~2.5% Mn ~3.0% Li ~Al balance, 0.01% super aluminum titanium boron (AlTi5B) 0.1 and AlTi5B 0.2 ).

[0106] Preparation method:

[0107] 1) Calculate the required raw materials according to the alloy composition ratio, and melt aluminum-silicon master alloy, aluminum-manganese master alloy, aluminum-beryllium master alloy, aluminum-lithium master alloy and aluminum and lithium in sequence under vacuum conditions of 700℃ to obtain aluminum alloy solution.

[0108] 2) Argon gas is introduced into the aluminum alloy solution for composite degassing and slag removal; a finer agent, super aluminum-titanium-boron, is added, and mechanical stirring is used to ensure that the finer agent is evenly distributed in the aluminum melt, with a stirring speed of 200 r·min. -1 The time is 10 minutes;

[0109] 3) After standing and cooling to room temperature, pour the mixture into a mold to form an aluminum frame;

[0110] 4) The aluminum frame is subjected to solution treatment and aging treatment at a heating rate of 10℃ / min. The solution treatment process is as follows: the first stage solution temperature is 480℃ and the holding time is 10h; the second stage solution temperature is 520℃ and the holding time is 8h. The aging treatment process is as follows: the first stage aging temperature is 130℃ and the holding time is 12h; the second stage aging temperature is 180℃ and the holding time is 4h, thus obtaining a high-performance aluminum alloy for the aluminum frame of the electrolytic cell.

[0111] Comparative Example 1

[0112] The aluminum alloy composition and its weight percentage are 5% Si to the balance Al, with no refining agent;

[0113] Preparation method:

[0114] 1) Calculate the required raw materials according to the alloy composition ratio, and melt the aluminum block and aluminum-silicon master alloy in sequence under vacuum conditions of 700℃ to obtain an aluminum alloy solution.

[0115] 2) Argon gas is introduced into the aluminum alloy solution for composite degassing and slag removal, and mechanical stirring is performed at a speed of 200 r / min. -1 The time is 10 minutes;

[0116] 3) After standing and cooling to room temperature, pour the mixture into a mold to form an aluminum frame.

[0117] 4) The aluminum frame is subjected to solution treatment and aging treatment at a heating rate of 10℃ / min. The solution treatment process is as follows: the first stage solution temperature is 480℃ and the holding time is 10h; the second stage solution temperature is 520℃ and the holding time is 8h. The aging treatment process is as follows: the first stage aging temperature is 130℃ and the holding time is 12h; the second stage aging temperature is 180℃ and the holding time is 4h, thus obtaining a high-performance aluminum alloy for the aluminum frame of the electrolytic cell.

[0118] Comparative Example 2

[0119] The aluminum alloy composition and its weight percentage are 5% Si~0.2% Be~1% Mn~0.5% Li~Al, without refining agents;

[0120] Preparation method:

[0121] 1) Calculate the required raw materials according to the alloy composition ratio, and melt aluminum-silicon master alloy, aluminum-beryllium master alloy, aluminum-manganese master alloy, aluminum-lithium master alloy and aluminum block in sequence under vacuum conditions of 700℃ to obtain aluminum alloy solution.

[0122] 2) Argon gas is introduced into the aluminum alloy solution for composite degassing and slag removal, and mechanical stirring is performed at a speed of 200 r / min. -1 The time is 10 minutes;

[0123] 3) After standing and cooling to room temperature, pour the mixture into a mold to form an aluminum frame.

[0124] 4) The aluminum frame is subjected to solution treatment and aging treatment at a heating rate of 10℃ / min. The solution treatment process is as follows: the first stage solution temperature is 480℃ and the holding time is 10h; the second stage solution temperature is 520℃ and the holding time is 8h. The aging treatment process is as follows: the first stage aging temperature is 130℃ and the holding time is 12h; the second stage aging temperature is 180℃ and the holding time is 4h, thus obtaining a high-performance aluminum alloy for the aluminum frame of the electrolytic cell.

[0125] Comparative Example 3

[0126] The aluminum alloy composition and its weight percentage are 6.5% Si~1.5% Be~1.5% Mn~1.5% Li~Al, without refining agents;

[0127] Preparation method:

[0128] 1) Calculate the required raw materials according to the alloy composition ratio, and melt aluminum-silicon master alloy, aluminum-beryllium master alloy, aluminum-manganese master alloy, aluminum-lithium master alloy and aluminum block in sequence under vacuum conditions of 700℃ to obtain aluminum alloy solution.

[0129] 2) Argon gas is introduced into the aluminum alloy solution for composite degassing and slag removal, and mechanical stirring is performed at a speed of 200 r / min. -1 The time is 10 minutes;

[0130] 3) After standing and cooling to room temperature, pour the mixture into a mold to form an aluminum frame.

[0131] 4) The aluminum frame is subjected to solution treatment and aging treatment at a heating rate of 10℃ / min. The solution treatment process is as follows: the first stage solution temperature is 480℃ and the holding time is 10h; the second stage solution temperature is 520℃ and the holding time is 8h. The aging treatment process is as follows: the first stage aging temperature is 130℃ and the holding time is 12h; the second stage aging temperature is 180℃ and the holding time is 4h, thus obtaining a high-performance aluminum alloy for the aluminum frame of the electrolytic cell.

[0132] Comparative Example 4

[0133] The alloy composition of Comparative Example 4 is the same as that of Example 4. The only difference in the preparation method is that in step 4), the aluminum frame is subjected to solution treatment and aging treatment at a heating rate of 10℃ / min. The solution treatment process is as follows: the solution temperature is 480℃ and the holding time is 10h; the aging treatment process is as follows: the aging temperature is 130℃ and the holding time is 12h; thus, a high-performance aluminum alloy for electrolytic cell aluminum frame is obtained.

[0134] The intergranular corrosion resistance, elastic modulus, and tensile properties after exposure at 300°C for 100 hours were tested on the aluminum alloy materials prepared in Examples 1-7 and Comparative Examples 1-4 of this invention. The results are shown in Table 1.

[0135] Table 1: Performance Testing Indicators of Aluminum Alloy Materials

[0136]

[0137]

[0138] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A high-performance aluminum alloy for an electrolytic cell frame, characterized in that, By mass percentage, it comprises the following components: Si 5%–8%, Be 0.5%–3.0%, Mn 0.5%–2.5%, Li 0.5%–3.0%, refining agent 0.01%–0.07%, total impurities ≤0.15%, and the balance being Al; The refining agent includes one or more of super aluminum titanium boron, alumina fiber, and carbon fiber.

2. The high-performance aluminum alloy according to claim 1, characterized in that, The refining agent is super aluminum-titanium-boron, and the aluminum-titanium-boron component is in the form of AlTi5B. 0.1 and AlTi5B 0.2 .

3. The high-performance aluminum alloy according to claim 1 or 2, characterized in that, The aluminum alloy has an elastic modulus ≥80GPa, a tensile strength ≥280MPa after 100 hours of heat exposure at 300℃, an elongation ≥8%, and an intergranular corrosion resistance level of 1 to 2.

4. The method for preparing the high-performance aluminum alloy according to any one of claims 1 to 3, characterized in that, Includes the following steps: 1) Weigh the raw materials according to the proportion and melt them to obtain an aluminum alloy solution. The raw materials include aluminum alloy, aluminum-silicon master alloy, lithium alloy, aluminum-manganese master alloy, aluminum-beryllium master alloy and / or aluminum-lithium master alloy. 2) Degas and remove slag from the aluminum alloy solution, add a refining agent and mix to obtain molten aluminum; 3) After cooling the molten aluminum to room temperature, pour it into a mold to form an aluminum frame; 4) The aluminum frame is subjected to solution treatment and aging treatment in sequence to obtain a high-performance aluminum alloy for the aluminum frame of the electrolytic cell.

5. The method for preparing the high-performance aluminum alloy according to claim 4, characterized in that, In step 1), the order of adding smelting raw materials is to add the intermediate alloy first, and then add the single-element alloy.

6. The method for preparing the high-performance aluminum alloy according to claim 4, characterized in that, The melting temperature in step 1) is 700-750℃, and the melting heating rate is 5-10℃ / min.

7. The method for preparing the high-performance aluminum alloy according to claim 4, characterized in that, Step 2) is performed under mechanical stirring conditions, with a stirring speed of 200–400 r·min. -1 The stirring time is 10 to 30 minutes.

8. The method for preparing the high-performance aluminum alloy according to claim 4, characterized in that, In step 3), the mold needs to be preheated to 200-300°C.

9. The method for preparing the high-performance aluminum alloy according to claim 4, characterized in that, Step 4) Solution treatment includes a first solution treatment and a second solution treatment. The first solution treatment temperature is 470-500℃ and the first solution treatment holding time is 6-10h. The second solution treatment temperature is 500-540℃ and the second solution treatment holding time is 8-10h.

10. The method for preparing the high-performance aluminum alloy according to claim 4, characterized in that, Step 4) aging treatment includes a first aging treatment and a second aging treatment. The temperature of the first aging treatment is 120-150℃ and the holding time of the first aging treatment is 10-16h. The temperature of the second aging treatment is 160-200℃ and the holding time of the second aging treatment is 2-6h.

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