Aluminum alloy and preparation method and application thereof

Abstract

The invention belongs to the technical field of alloys, and particularly relates to an aluminum alloy and a preparation method and application thereof. Relative to the total weight of the aluminum alloy, the aluminum alloy comprises the following components in percentage by mass: 0.7-2.0% of Fe, 0.6-2.0% of Mn, Silt and the balance of Al. 0.1%, 0-1% of Mg and 0-1% of Zn; or 0.7%-2.0% of Fe, 0.6%-2.0% of Mn and 0 < Silt; 2.0%, 0 < Srlt; 2.0%, 0-0.3% of V, and Mglt; 0.2%, and the balance being Al and inevitable impurities. The aluminum alloy disclosed by the invention is simple in component, and has relatively good economical efficiency and good recoverability and reusability. Through the reasonable proportion and content of the metal elements, the alloy has good high-pressure casting performance and high solidus temperature, and the solderability and the service performance of brazed castings are guaranteed.

Description

Technical Field

[0001] The present application belongs to the field of alloy technology, and in particular relates to an aluminum alloy and a preparation method and application thereof. Background Art

[0002] Under the general trend of global energy conservation and emission reduction, automobile manufacturing and use are important areas of energy conservation and emission reduction. Electric vehicles have replaced traditional fuel vehicles and have become a globally recognized solution for energy conservation and emission reduction. As we all know, electric vehicles do not burn fossil fuels or produce tail gas emissions during use, which eliminates the contribution of tail gas to the greenhouse effect. However, so far, the manufacturing process of electric vehicles still relies heavily on fossil fuels or the electricity generated by them, which also produces more greenhouse gas emissions.

[0003] In order to improve the driving range and safety performance of electric vehicles, major automobile manufacturers are increasingly using light alloys. Among them, aluminum alloy has become the body material favored by mainstream electric vehicles due to its low density, high specific strength, good processing performance and abundant resources. Among them, as a near-net forming process, aluminum alloy die-casting parts are often used in key parts of automobiles due to their high production efficiency, excellent and stable performance, and the ability to be designed and processed into complex shapes, which reduces the processing steps and material waste required for traditional parts, and effectively reduces the energy consumption and carbon emissions of the parts processing process.

[0004] In the production process of parts such as the thermal management system of automobiles, brazing only melts the brazing material but not the parts to be brazed. The brazing process can minimize the dimensional deformation and performance degradation of the parts and is a popular connection process. However, brazing of aluminum alloy castings is not an easy task. It requires not only sufficient surface cleanliness, broken oxide film and anti-secondary oxidation measures, but also strict matching of the melting temperature range of the alloy to be welded and the brazing material. Aluminum alloy castings often contain a large number of pores or shrinkage defects. At conventional brazing temperatures (such as 600°C), the pores / shrinkage cavities close to the outer surface of the casting will expand, thereby affecting the quality of brazing. Therefore, it is urgent to develop an aluminum alloy to improve the brazing ability of aluminum alloys under conventional processes. Summary of the invention

[0005] The purpose of the present application is to provide an aluminum alloy and a preparation method and application thereof, aiming to solve the problem of poor brazing properties of existing aluminum alloy castings under conventional processes to a certain extent.

[0006] In order to achieve the above application purpose, the technical solution adopted in this application is as follows:

[0007] In a first aspect, the present application provides an aluminum alloy, comprising the following components in percentage by weight relative to the total weight of the aluminum alloy:

[0008] Fe is 0.7% to 2.0%, Mn is 0.6% to 2.0%, Si < 0.1%, Mg is 0 to 1%, Zn is 0 to 1%, and the balance is Al and unavoidable impurities;

[0009] Alternatively, Fe is 0.7% to 2.0%, Mn is 0.6% to 2.0%, 0<Si<2.0%, 0<Sr<2.0%, V is 0 to 0.3%, Mg<0.2%, and the balance is Al and unavoidable impurities.

[0010] In some possible implementations, the aluminum alloy includes components in mass percentage relative to the total weight: Fe is 0.7% to 2.0%, Mn is 0.6% to 2.0%, Si is 0.01% to 2.0%, Sr is 0.01% to 2.0%, Mg<0.1%, and the remainder is Al and unavoidable impurities.

[0011] In some possible implementations, the aluminum alloy includes components in mass percentage, relative to the total weight: Fe is 0.7% to 2.0%, Mn is 0.6% to 2.0%, Si is 0.01% to 2.0%, Sr is 0.01% to 2.0%, V is 0.01% to 0.3%, Mg<0.1%, and the remainder is Al and unavoidable impurities.

[0012] In some possible implementations, when the aluminum alloy contains both Si and Sr elements, the Sr and Si elements satisfy the relationship: 22*Sr (wt.%) ≥ 30*Si (wt.%) -3.

[0013] In some possible implementations, the aluminum alloy includes components in percentage by mass, relative to the total weight: Fe is 1.0% to 2.0%, Mn is 1.0% to 2.0%, Si is 0.4% to 1.5%, Sr is 0.5% to 2.0%, Mg<0.1%, and the remainder is Al and unavoidable impurities.

[0014] In some possible implementations, the aluminum alloy includes components in mass percentage, relative to the total weight: Fe is 1.0% to 2.0%, Mn is 1.0% to 2.0%, Si is 0.5% to 1.5%, Sr is 1% to 2.0%, V is 0.1% to 0.2%, Mg<0.1%, and the remainder is Al and unavoidable impurities.

[0015] In some possible implementations, based on the total weight of the aluminum alloy, the components include: 1.25% Fe, 1.66% Mn, 0.46% Si, 0.57% Sr, and the remainder Al and unavoidable impurities.

[0016] In some possible implementations, based on the total weight of the aluminum alloy, the components include: 1.64% Fe, 1.72% Mn, 0.95% Si, 1.32% Sr, 0.18% V, and the remainder Al and unavoidable impurities.

[0017] In some possible implementations, based on the total weight of the aluminum alloy, the components include: 1.56% Fe, 1.67% Mn, 1.5% Si, 2.0% Sr, and the remainder Al and unavoidable impurities.

[0018] In some possible implementations, based on the total weight of the aluminum alloy, the components include: 1.56% Fe, 1.67% Mn, 0.66% Si, 1.04% Sr, and the remainder Al and unavoidable impurities.

[0019] In some possible implementations, the aluminum alloy includes components in mass percentage relative to the total weight: Fe is 0.9% to 1.5%, Mn is 0.6% to 1.5%, Si<0.05%, Mg is 0 to 1%, Zn is 0 to 1%, and the balance is Al and unavoidable impurities.

[0020] In some possible implementations, based on the total weight of the aluminum alloy, the components include: 1.1% Fe, 0.93% Mn, 0.03% Si, 0.95% Mg, 0.87% Zn, and the remainder Al and unavoidable impurities.

[0021] In some possible implementations, based on the total weight of the aluminum alloy, the components, including mass percentage, are: Fe is 0.91%, Mn is 0.93%, Si is 0.03%, and the remainder is Al and unavoidable impurities.

[0022] In some possible implementations, the solidus temperature of the aluminum alloy is not less than 610°C.

[0023] In a second aspect, the present application provides a method for preparing an aluminum alloy, comprising the following steps:

[0024] Obtaining the metal raw material components in the formula amount according to the above aluminum alloy;

[0025] Smelting the metal raw material components into alloy liquid;

[0026] The alloy liquid is subjected to refining, degassing and slag removal treatments in sequence, and is formed into aluminum alloy parts.

[0027] In a third aspect, the present application provides an application of an aluminum alloy, wherein the above-mentioned aluminum alloy or the aluminum alloy prepared by the above-mentioned method is applied to at least one field of automobile, electronics industry, communication equipment, aerospace, and shipbuilding.

[0028] The aluminum alloy provided in the first aspect of the present application is based on the Al-Fe binary alloy system. Based on the Al-Fe binary phase diagram, when the iron content is 0.7% to 2.0%, there is an Al-Al3Fe14 binary eutectic system, and the theoretical eutectic temperature is 655°C. The existence of the Al-Fe binary eutectic system not only ensures the casting performance of the alloy, but also improves the solidus temperature of the aluminum alloy, and the high solidus is the key characteristic required for the brazing process. At the same time, appropriate Mn elements are added to the alloy to improve the strength of the Al-Fe binary alloy and increase its demolding performance. On the one hand, when the content of Si element is controlled to be <0.1wt.%, an appropriate amount of Mg and / or Zn can be added to the aluminum alloy to strengthen the cast properties of the alloy. On the other hand, when the content of Mg is controlled to be less than 0.2%, appropriate Si elements are added to the aluminum alloy to improve the fluidity and heat cracking resistance of the material and reduce the solidification shrinkage of the alloy, so that the alloy has good castability under the die-casting process and improves the compatibility of the alloy with silicon pollution from conventional die-casting equipment, thereby improving the versatility of the alloy on conventional die-casting equipment. At the same time, Sr elements can be added to the aluminum alloy to bind Si elements, thereby inhibiting the precipitation of eutectic silicon phase and ensuring that the alloy has a higher solidus temperature, thus ensuring the brazing of the alloy under conventional processes. Furthermore, V elements can be added to form Al-Fe-V ternary eutectic with the Al-Fe binary alloy system to provide a grain refinement effect.

[0029] The preparation method of the aluminum alloy provided in the present application obtains the metal raw material components of the formula according to the above-mentioned aluminum alloy, and after smelting into alloy liquid, it can be formed into aluminum alloy castings through refining, degassing and slag removal. The preparation process is simple and suitable for industrial large-scale production and application. The prepared aluminum alloy does not contain precious metals or rare alloy elements, has good economy, simple alloy composition, and good recyclability and reusability. By reasonably matching the content of metal elements, it is ensured that the aluminum alloy has reliable mechanical properties before and after brazing, and has good high-pressure casting performance, has a high solidus temperature, ensures the castability and service performance of the cast parts, and ensures the welding quality of the casting and the appearance quality of the casting after welding.

[0030] The aluminum alloy of the present application has good high-pressure casting performance, reliable mechanical properties before and after brazing, and ensures the welding quality and appearance quality of the casting after welding, as well as the castability and service performance of the casting parts. Therefore, it can be widely used in the fields of automobiles, electronics industry, communication equipment, aerospace, shipbuilding, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 It is a schematic diagram of a process for preparing an aluminum alloy provided in an embodiment of the present application;

[0033] Figure 2 is a picture of the aluminum alloy casting provided in Example 1 of the present application;

[0034] Figure 3 is the metallographic structure of the aluminum alloy casting provided in Example 6 of the present application;

[0035] Figure 4 This is a solidification simulation test diagram of an aluminum alloy under non-equilibrium cooling conditions provided in Example 6 of the present application;

[0036] Figure 5 The aluminum-iron pseudo-binary phase diagram of the aluminum alloy provided in Example 6 of the present application. DETAILED DESCRIPTION

[0037] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0038] In this application, the term "and / or" describes the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0039] In this application, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b or c", or "at least one of a, b and c", can all represent: a, b, c, ab (i.e. a and b), ac, bc, or abc, where a, b, c can be single or multiple, respectively.

[0040] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0041] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0042] The weight of the relevant components mentioned in the embodiments of the present specification can not only refer to the specific content of each component, but also represent the proportional relationship between the weights of the components. Therefore, as long as the content of the relevant components in the embodiments of the present specification is proportionally enlarged or reduced, it is within the scope disclosed in the embodiments of the present specification. Specifically, the mass described in the embodiments of the present specification can be μg, mg, g, kg and other mass units known in the chemical industry.

[0043] The terms "first" and "second" are used only for descriptive purposes to distinguish objects such as substances from each other, and should not be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. For example, without departing from the scope of the embodiments of the present application, the first XX may also be referred to as the second XX, and similarly, the second XX may also be referred to as the first XX. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0044] In automobile production, brazing is a popular connection process. Brazing is a welding method that uses a brazing material with a lower melting point than the metal to be welded. After being heated to the melting temperature of the brazing material, it relies on capillary action to fill the joint gap and diffuse with the parent material to achieve connection. Since only the brazing material is melted, but not the parts to be brazed, the brazing process can minimize the dimensional deformation and performance degradation of the parts. More importantly, based on a reliable brazing structure design, the process can effectively connect the parts to be welded together, provide good sealing performance, and ensure that the inner cavity of the brazed parts can work stably under certain pressure and temperature conditions without leakage.

[0045] At present, it has become an industry trend to use near-net-shape casting processes, such as high-pressure casting, to replace machining or forging processes with high energy consumption and high material waste rates. In the era of internal combustion engines, most of the parts on automobiles, such as the fluid management system of thermal management, were formed by forging or extrusion of deformed aluminum alloys and then connected by brazing. In today's era of automotive electrification, it is a general trend to replace deformed parts with cast parts. Taking the fluid relationship system of the thermal management module as an example, by converting the cooling valve plate from an aluminum forging part to a cast aluminum part, and then connecting the cooling plate through a brazing process, the sealing and pressure resistance of the inner cavity are guaranteed. However, brazing of aluminum alloy castings is not an easy task, and the main reasons are as follows: First, the surface activity of aluminum alloy is high, and it is easy to produce surface oxidation under brazing conditions. Therefore, it is necessary to provide sufficient surface cleanliness and anti-oxidation measures. Second, the solidus temperature of conventional aluminum alloy Al-Si system castings is lower than or close to the liquidus temperature of conventional brazing materials, and the control of the brazing temperature window is very strict or even impossible to achieve. Therefore, it is necessary to strictly match the melting temperature range of the alloy to be welded and the brazing material. Thirdly, aluminum alloy castings often contain a large number of pores or shrinkage defects. At conventional brazing temperatures, such as 600°C, the pores / shrinkage cavities near the outer surface of the casting will expand, forming surface bulges, which will deteriorate the matching gap between the parts to be welded, thereby affecting the quality of brazing.

[0046] Based on the above-mentioned aluminum alloy brazing problem, in order to improve the brazing property of aluminum alloy under conventional process, two research and development directions have been generated. The first research and development direction is to reduce the liquidus temperature of the brazing filler metal to below the solidus temperature of the conventional aluminum alloy to be welded. In this way, brazing can be carried out at a solidus temperature lower than the solidus temperature of the conventional aluminum alloy casting to be welded, ensuring the quality of brazing. The advantage of this direction is that the brazing temperature is low, and the energy consumption and related carbon emissions are relatively low. At the same time, conventional aluminum alloy casting materials, especially Al-Si alloy castings with the largest amount in the industry, can also be brazed without increasing the solidus temperature of the aluminum alloy casting materials by adding expensive or rare alloying elements. However, the disadvantage of this direction is that there is currently no brazing filler metal material on the market that can guarantee the reliability of the brazing joint on the casting surface, brazing strength, corrosion resistance and economy from an all-round perspective. The second research and development direction is to increase the solidus temperature of the aluminum alloy casting material to be welded to above the conventional brazing temperature. In this way, brazing can be carried out using conventional Al-Si brazing filler metal and conventional processes. The advantage of this direction is that the industry has mature experience with conventional Al-Si brazing filler metals and conventional brazing processes, and the consistency and stability of brazing quality are guaranteed. However, the disadvantage of this direction is that the high-temperature brazable aluminum alloys on the market currently guarantee both high solidus temperature and high-pressure castability by adding precious or rare alloying elements such as nickel and rare earth. This has caused a significant increase in the cost of this type of new high-temperature brazable aluminum alloy, and the high content of precious or rare alloying elements added cannot be easily recycled and reused in other alloy systems, which has brought pressure to the industry supply chain system and social resources and environmental protection.

[0047] In some studies, a series of aluminum alloys have been developed, which ensure the castability and high solidus of the alloy not less than 630℃ by adding up to 5wt.% nickel Ni or / and up to 10% rare earth cerium Ce, with up to 1.2wt.% iron and up to 3wt.% manganese Mn. The design selects alloy elements such as Fe / Mn / Ni / Ce / Cr that do not significantly reduce the solidus temperature of aluminum materials, and introduces Al-Fe(Mn)-Ni and Al-Fe(Mn)-Ce ternary eutectic systems to ensure the casting performance of the alloy, providing a new design idea for the development of aluminum casting alloys for industrial mass production. However, the high cost of Ni and Ce, and the complex composition design, are not conducive to the recycling and reuse of related waste materials.

[0048] In some studies, a new type of aluminum alloy was developed by adding 0.6-1.5 (wt.%) manganese Mn and 5-12 (wt.%) lanthanum cerium rare earth. In addition, Al-Fe-Mn-RE based system was developed. These studies ensured its castability and solidus temperature by adding rare metal elements, and the raw material cost was high.

[0049] In some studies, the alloys developed are based on Al-Fe-Mn, and are alloyed by adding no more than 1wt.% of silicon Si and up to 0.15wt.% of titanium Ti. However, when the Si content is higher than 0.2wt.%, the solidus temperature of the alloy will be significantly reduced to about 577°C. In addition, due to its relatively low Fe and Mn addition, the strength of the alloy is relatively low, which may bring challenges to the demolding process during the die casting process, and may also bring challenges to the service performance of actual parts.

[0050] Therefore, in order to develop an aluminum alloy that does not use precious metals or rare metal elements, has low cost and simple composition, improve the brazing ability of the aluminum alloy under conventional processes, and ensure that the alloy has reliable mechanical properties before and after brazing. The embodiments of the present application provide an aluminum alloy and a preparation method and application thereof. For ease of understanding, the present application is specifically described through the following embodiments.

[0051] It should be understood that the following embodiments are only used to further illustrate the present application but are not used to limit the scope of the present application.

[0052] In a first aspect, an embodiment of the present application provides an aluminum alloy, comprising the following components in percentage by weight relative to the total weight of the aluminum alloy:

[0053] Fe is 0.7% to 2.0%, Mn is 0.6% to 2.0%, Si < 0.1%, Mg is 0 to 1%, Zn is 0 to 1%, and the balance is Al and unavoidable impurities;

[0054] Alternatively, Fe is 0.7% to 2.0%, Mn is 0.6% to 2.0%, 0<Si<2.0%, 0<Sr<2.0%, V is 0 to 0.3%, Mg<0.2%, and the balance is Al and unavoidable impurities.

[0055] It should be noted that, in the aluminum alloy formula of the embodiment of the present application, “~” includes endpoint values. For example, Fe is 0.7%~2.0%, which means that the Fe content is 0.7% to 2.0%, and can take two endpoint values ​​of 0.7% and 2.0%.

[0056] The aluminum alloy provided in the first aspect of the embodiment of the present application is based on the Al-Fe binary alloy system. Based on the Al-Fe binary phase diagram, when the iron content is 0.7% to 2.0%, there is an Al-Al3Fe 14The binary eutectic system has a theoretical eutectic temperature of 655°C. Due to the existence of the Al-Fe binary eutectic system, not only the casting performance of the alloy is guaranteed, but also the solidus temperature of the aluminum alloy can be increased, and the high solidus is the key characteristic required for the brazing process. At the same time, appropriate Mn elements are added to the alloy to improve the strength of the Al-Fe binary alloy and increase its demolding performance. On the one hand, when the content of Si element is controlled to be <0.1wt.%, an appropriate amount of Mg and / or Zn can be added to the aluminum alloy to strengthen the cast properties of the alloy. On the other hand, when the content of Mg element is controlled to be <0.2%, appropriate Si elements are added to the aluminum alloy to improve the fluidity and heat cracking resistance of the material and reduce the solidification shrinkage of the alloy, so that the alloy has good castability under the die-casting process, and improves the compatibility of the alloy with silicon pollution from conventional die-casting equipment, thereby improving the versatility of the alloy on conventional die-casting equipment. Sr can be added to the aluminum alloy to bind Si, thereby inhibiting the precipitation of eutectic silicon phase and ensuring that the alloy has a higher solidus temperature, thus ensuring the brazing of the alloy under conventional processes. In addition, V can be added to form Al-Fe-V ternary eutectic with the Al-Fe binary alloy system to provide a grain refinement effect.

[0057] Therefore, the aluminum alloy provided in the embodiment of the present application does not contain precious metals such as Ni or rare alloying elements such as La / Ce, and has good economy. The alloy composition is simple, and it has good recyclability and reuse, which reduces the pressure on the industry supply chain system and social resources and the environment. By reasonably matching the content of metal elements, it is ensured that the aluminum alloy has reliable mechanical properties before and after brazing, thereby ensuring the castability and service performance of the cast parts. In addition, the aluminum alloy has good high-pressure casting performance, that is, the aluminum liquid has good flowability, heat cracking resistance and controllable solidification shrinkage. At the same time, the aluminum alloy has a higher solidus temperature, which is very suitable for brazing using conventional Al-Si brazing fillers and under conventional brazing conditions, such as 600°C controlled atmosphere brazing furnace or vacuum brazing furnace, to ensure the welding quality of the parts and the appearance quality of the castings after welding.

[0058] In the aluminum alloy of the present application, since the melting points of Mg / Zn are low (approximately 650°C and 419°C, respectively), and the eutectic temperature of Si and Al is 577°C, the large addition of these three elements will significantly reduce the solidus temperature of the alloy. In addition, the chemical properties of Mg and Zn elements are active, Mg is easy to volatilize and oxidize, and Zn is easy to volatilize, which will have a negative impact on the brazing performance of the alloy or the brazing equipment. Therefore, the type and content of each metal element in the aluminum alloy are strictly controlled.

[0059] In some embodiments, the total weight of the aluminum alloy is 100%. In some possible implementations, relative to the total weight of the aluminum alloy, the components including the mass percentage content are: Fe is 0.7% to 2.0%, Mn is 0.6% to 2.0%, Si<0.1%, Mg is 0 to 1%, Zn is 0 to 1%, and the balance is Al and unavoidable impurities. This embodiment includes at least two cases: In some embodiments, relative to the total weight of the aluminum alloy, the components including the mass percentage content are: Fe is 0.7% to 2.0%, Mn is 0.6% to 2.0%, Si<0.1%, and the balance is Al and unavoidable impurities. In other embodiments, relative to the total weight of the aluminum alloy, the components including the mass percentage content are: Fe is 0.7% to 2.0%, Mn is 0.6% to 2.0%, Si<0.1%, 0<Mg<1%, 0<Zn<1%, and the balance is Al and unavoidable impurities.

[0060] In some possible implementations, the components include, by mass percentage, relative to the total weight of the aluminum alloy: Fe is 0.9% to 1.5%, Mn is 0.6% to 1.5%, Si<0.05%, Mg is 0 to 1%, Zn is 0 to 1%, and the balance is Al and unavoidable impurities.

[0061] In some specific implementations, based on the total weight of the aluminum alloy, the components include: 1.1% Fe, 0.93% Mn, 0.03% Si, 0.95% Mg, 0.87% Zn, and the remainder Al and unavoidable impurities.

[0062] In some specific implementations, based on the total weight of the aluminum alloy, the components include: 0.91% Fe, 0.93% Mn, 0.03% Si, and the remainder Al and unavoidable impurities.

[0063] The brazed die-casting alloy developed in the above embodiment of the present application is based on the Al-Fe binary alloy system. Based on the Al-Fe binary phase diagram, when the iron content is 0.7% to 2.0%, there is an Al-Al3Fe 14The binary eutectic system has a theoretical eutectic temperature of 655°C. The existence of this Al-Fe binary eutectic system not only ensures the casting performance of the alloy, but also ensures that the solidus temperature of the alloy is not lower than about 610°C, and the high solidus is the key characteristic required for the brazing process. However, Al-Fe binary alloys with iron content below 2wt.% are not suitable for high-pressure casting. The main reason is that the alloy strength is too low. During the demolding process of the high-pressure casting process, the load applied by the demolding ejector pin can easily cause serious deformation of the Al-Fe casting. At the same time, part of the runner or slag bag may remain in the mold, reducing the service life of the mold and affecting the continuous production of die casting. For this reason, the embodiment of the present application adds appropriate Mn elements to the alloy to improve the strength of the Al-Fe binary alloy and increase its demolding performance. The melting point of the Mn element is high, and the Al-Mn binary system has an Al-Al6 (FeMn) binary eutectic system when the Mn content is 0.6% to 2.0%, and the theoretical eutectic temperature is 658°C. Therefore, adding an appropriate amount of Mn element to the Al-Fe binary system can not only not reduce the solidus temperature of the parent alloy, but also introduce a new intermetallic phase Al6 (FeMn) to strengthen the parent alloy. After research, it was found that when the Fe content of Al-Fe-Mn is 0.7% to 2.0% (specifically 1.2%) and the Mn content is 0.6% to 2.0% (specifically 1.64%), there is a ternary eutectic system, and the existence of the ternary eutectic system is beneficial to the casting performance of the alloy. Therefore, the added content of the Mn element is 0.6wt.%-2.0wt.%. In some application scenarios, single elements Mg or Zn, or Mg+Zn, can be added to the brazable die-casting alloy to enhance the cast properties of the alloy and improve the high-pressure casting performance of the material. When it is necessary to add, the addition amount of a single element of Mg or Zn should not exceed 1.0wt.% to ensure that the solidus temperature of the aluminum alloy is not lower than 610℃.

[0064] In some possible implementations, the components including the mass percentage relative to the total weight of the aluminum alloy are as follows: Fe is 0.7% to 2.0%, Mn is 0.6% to 2.0%, 0<Si<2.0%, 0<Sr<2.0%, V is 0 to 0.3%, Mg<0.2%, and the remainder is Al and unavoidable impurities. This embodiment includes at least two cases:

[0065] In some embodiments, the aluminum alloy includes the following components in percentage by mass, relative to the total weight: Fe is 0.7% to 2.0%, Mn is 0.6% to 2.0%, 0<Si<2.0%, 0<Sr<2.0%, Mg<0.2%, and the remainder is Al and unavoidable impurities.

[0066] In a further embodiment, the aluminum alloy includes components in percentage by mass, relative to the total weight: Fe is 0.7% to 2.0%, Mn is 0.6% to 2.0%, Si is 0.01% to 2.0%, Sr is 0.01% to 2.0%, Mg<0.1%, and the remainder is Al and unavoidable impurities.

[0067] In a further embodiment, the components including mass percentage relative to the total weight of the aluminum alloy are: Fe is 0.7% to 2.0%, Mn is 0.6% to 2.0%, 0.1%<Si<2.0%, 0<Sr<2.0%, Mg<0.2%, and the balance is Al and unavoidable impurities.

[0068] In some possible implementations, the aluminum alloy includes components in percentage by mass, relative to the total weight: Fe is 1.0% to 2.0%, Mn is 1.0% to 2.0%, Si is 0.4% to 1.5%, Sr is 0.5% to 2.0%, Mg<0.1%, and the remainder is Al and unavoidable impurities.

[0069] In other embodiments, the components including mass percentage relative to the total weight of the aluminum alloy are: Fe is 0.7% to 2.0%, Mn is 0.6% to 2.0%, 0<Si<2.0%, 0<Sr<2.0%, 0<V<0.3%, Mg<0.2%, and the balance is Al and unavoidable impurities.

[0070] In a further embodiment, the components including mass percentage relative to the total weight of the aluminum alloy are: Fe is 0.7% to 2.0%, Mn is 0.6% to 2.0%, Si is 0.01% to 2.0%, Sr is 0.01% to 2.0%, 0<V<0.3%, Mg<0.1%, and the balance is Al and unavoidable impurities.

[0071] In a further embodiment, the components including mass percentage relative to the total weight of the aluminum alloy are: Fe is 0.7% to 2.0%, Mn is 0.6% to 2.0%, 0.1%<Si<2.0%, 0<Sr<2.0%, V is 0.01% to 0.3%, Mg<0.2%, and the balance is Al and unavoidable impurities.

[0072] In some possible implementations, the aluminum alloy includes components in mass percentage, relative to the total weight: Fe is 1.0% to 2.0%, Mn is 1.0% to 2.0%, Si is 0.5% to 1.5%, Sr is 1% to 2.0%, V is 0.1% to 0.2%, Mg<0.1%, and the remainder is Al and unavoidable impurities.

[0073] In some application scenarios of the embodiments of the present application, in order to further improve the fluidity and heat cracking resistance of the material and reduce the solidification shrinkage of the alloy, an appropriate Si element is added to the aluminum alloy. When the Si element is added to the aluminum matrix, it will not exist in the aluminum matrix phase in the form of solid solution during the solidification process. On the contrary, Si will precipitate in the form of a precipitate phase such as a eutectic silicon phase or a Mg2Si phase. When the alloy element ratio is not properly added and the eutectic silicon phase or the Mg2Si intermetallic phase is precipitated, it is inevitably accompanied by a significant decrease in the solidus temperature. Taking the precipitation of eutectic silicon as an example, when the eutectic silicon phase is precipitated in the aluminum alloy, its precipitation temperature is in the range of 570°C to 577°C. In this case, the solidus temperature of the alloy is significantly lower than the conventional brazing temperature (about 600°C). Therefore, in order to ensure that the solidus temperature of the aluminum alloy is not lower than the conventional brazing temperature, the Si content must be adjusted within a suitable range and combined with the addition of other alloy elements to avoid the precipitation of low-melting-point intermetallic phases. The present application embodiment study found that the addition content of Si element needs to be controlled at 0.01wt.% to 2.0wt.%. In addition, in order to overcome the problem of the solidus temperature drop caused by Si addition, the present application embodiment considers adding Sr element to the aluminum alloy. In general, Sr is a metamorphic element of the eutectic silicon phase in the Al-Si casting alloy. By adding elements at the level of 100 to 200ppm, the eutectic silicon phase will be transformed from rod-shaped to coral-shaped, thereby improving the plasticity and toughness of the cast alloy. In the aluminum alloy of the present application embodiment, Sr combines with Si to generate Al2Si2Sr before the precipitation of the α-Al phase, thereby reducing the free Si in the remaining aluminum liquid, avoiding the subsequent precipitation of the eutectic silicon phase or Mg2Si phase, and ensuring that the solidus temperature of the alloy is higher than 610°C. In addition, in aluminum alloys containing Si addition, it is necessary to limit the content of the alloying element Mg to avoid the precipitation of the Mg / Si intermetallic phase, thereby reducing the solidus temperature of the alloy. Under this requirement, the Mg content is not higher than 0.2wt.%.

[0074] In some application scenarios, the V element can also be added as an alloying element. The V element can form an Al-Fe-V ternary eutectic with the Al-Fe binary alloy system. At the ternary eutectic point, when the V element content is 0.13wt.%, the solidus temperature is about 654°C, so the addition of the V element will not significantly reduce the solidus temperature of the aluminum alloy. At the same time, the V element precipitates the Al-V intermetallic phase in the aluminum melt before the α-Al phase, thereby forming heterogeneous nucleation points of the α-Al phase and the Al-Fe intermetallic phase, providing a grain refinement effect. In the aluminum alloy of the embodiment of the present application, the added content of the V element is 0.01% to 0.3wt.%.

[0075] In some possible implementations, when the aluminum alloy contains both Si and Sr elements, in order to offset the effect of Si on reducing the solidus temperature of the aluminum alloy, the Sr element and the Si element satisfy the relationship: 22*Sr(wt.%)≥30*Si(wt.%)-3. In the embodiment of the present application, the amount of Sr added depends on the Si content in the alloy. When the minimum amount of Sr added and the addition relationship of the Si content are 22*Sr(wt.%)=30*Si(wt.%)-3, Sr combines with Si to generate Al2Si2Sr before the α-Al phase precipitates, thereby reducing the free Si in the remaining aluminum liquid, avoiding the subsequent precipitation of eutectic silicon phase or Mg2Si phase, and is conducive to ensuring that the solidus temperature of the alloy is higher than 640°C.

[0076] In some specific implementations, based on the total weight of the aluminum alloy, the components include: 1.25% Fe, 1.66% Mn, 0.46% Si, 0.57% Sr, and the remainder Al and unavoidable impurities.

[0077] In some specific implementations, based on the total weight of the aluminum alloy, the components include: 1.64% Fe, 1.72% Mn, 0.95% Si, 1.32% Sr, 0.18% V, and the remainder is Al and unavoidable impurities.

[0078] In some specific implementations, based on the total weight of the aluminum alloy, the components include: 1.56% Fe, 1.67% Mn, 1.5% Si, 2.0% Sr, and the remainder Al and unavoidable impurities.

[0079] In some specific implementations, based on the total weight of the aluminum alloy, the components include: 1.56% Fe, 1.67% Mn, 0.66% Si, 1.04% Sr, and the remainder is Al and unavoidable impurities.

[0080] In the above embodiments of the present application, the aluminum alloy has at least one of the following beneficial effects:

[0081] (1) Conventional elements such as Fe, Mn, Si, Sr, Mg, and Zn are used as the main alloying elements, and precious metals such as Ni or rare elements such as La / Ce are not used, which has better economic efficiency;

[0082] (2) Aluminum alloy has simple composition and good recyclability, which reduces the pressure on the industry supply chain system, social resources and the environment;

[0083] (3) By adding Si elements, the aluminum alloy has good fluidity and heat cracking resistance, so that the aluminum alloy has good castability under the die-casting process, and improves the alloy's compatibility with silicon pollution from conventional die-casting equipment, thereby improving the versatility of the aluminum alloy on conventional die-casting equipment;

[0084] (4) The first to add Sr to aluminum alloy to bind Si, thereby inhibiting the precipitation of eutectic silicon phase and enabling the solidus temperature of aluminum alloy to reach above 610°C, thus ensuring the brazing of aluminum alloy under conventional processes. At the same time, the mathematical relationship between the minimum addition content of Sr element and the content of Si element was developed, which can more accurately control the performance of aluminum alloy.

[0085] (5) By rationally proportioning the content of metal elements in the aluminum alloy, the aluminum alloy is guaranteed to have reliable mechanical properties before and after brazing, thereby ensuring the castability and service performance of the casting parts.

[0086] In some possible implementations, the solidus temperature of the aluminum alloy is not lower than 610°C, and can be specifically any typical but non-limiting point value such as 610°C, 620°C, 630°C, 640°C, 650°C, 660°C, or an interval value between any two points.

[0087] In some preferred embodiments, the solidus temperature of the aluminum alloy is not less than 630° C. Further, the solidus temperature of the aluminum alloy is not less than 640° C.

[0088] In a second aspect, the present application provides a method for preparing an aluminum alloy, as shown in the attached Figure 1 As shown, the following steps are included:

[0089] S10. Obtaining the metal raw material component according to the above-mentioned aluminum alloy formula;

[0090] S20. Melting the metal raw material components into a liquid alloy;

[0091] S30. The alloy liquid is subjected to refining, degassing and slag removal treatments in sequence to obtain aluminum alloy parts.

[0092] The method for preparing an aluminum alloy provided in an embodiment of the present application obtains a formula amount of metal raw material components according to the above-mentioned aluminum alloy, and after smelting into an alloy liquid, it can be formed into an aluminum alloy casting through refining, degassing and slag removal. The preparation process is simple and suitable for industrial large-scale production and application. The prepared aluminum alloy does not contain precious metals or rare alloy elements, has good economy, simple alloy composition, and good recyclability and reusability. Through the reasonable ratio and content of metal elements, on the one hand, the alloy has good high-pressure casting performance, and on the other hand, the alloy has a higher solidus temperature, which ensures the brazing ability and the service performance of the casting after brazing.

[0093] In the above step S10:

[0094] In some possible implementations, the metal raw material component is in the form of a single metal and / or a master alloy.

[0095] In some possible implementations, the metal raw material component includes Al ingot, elemental Si, Al-Mn master alloy, Al-Sr master alloy, Al-Fe master alloy, Al-V master alloy, Al-Mg master alloy or Zn ingot.

[0096] In some possible implementations, the metal raw material components are obtained in a formula according to the above-mentioned aluminum alloy, wherein aluminum is in the form of Al ingot (for example, A00), Si element is added in the form of elemental silicon, Mn element is added in the form of Al-Mn master alloy, Sr element is added in the form of Al-Sr rod master alloy, Fe element is added in the form of Al-Fe master alloy, V element is added in the form of Al-V master alloy, Mg element is added in the form of Al-Mg master alloy, and Zn element is added in the form of pure zinc ingot.

[0097] In the above step S20:

[0098] In some embodiments, the step of melting the metal raw material components into a molten alloy comprises:

[0099] S21. Melting aluminum ingot: placing A00 and silicon into a resistance crucible for heating and melting, and controlling the temperature of the aluminum liquid between 720°C and 740°C;

[0100] S22. Adding the master alloy: When the temperature of the aluminum liquid reaches 730°C to 735°C, detect the composition in the furnace, add the required components, weigh the required master alloy and bake it, add the dried Al-Mn master alloy, Al-Fe master alloy, Al-Ti and other master alloys to the aluminum liquid, heat the aluminum liquid to 740°C to 760°C, keep it warm for 10-30 minutes, and ensure that all the added master alloys are melted;

[0101] S23. Press the Al-Sr master alloy into the aluminum liquid, and use an iron rake to continuously stir the bottom without damaging the liquid surface. Repeat this action three times. After stirring, test whether the strontium content meets the requirements. When it meets the standard requirement of more than 10%, the alloy liquid is obtained and set aside.

[0102] In the embodiment of the present application, the metal raw material components in the aluminum alloy are melt-mixed in steps and stages according to the melting points of different metal raw materials, so as to ensure the stability of each metal element in the alloy liquid and avoid the volatilization of certain metal elements due to inappropriate melting temperature.

[0103] In the above step S30: the alloy liquid is subjected to refining, degassing and slag removal treatments in sequence, in order to remove hydrogen and slag in the aluminum liquid.

[0104] In some possible implementations, the speed of the refining and degassing treatment is 150 rpm to 300 rpm, the gas introduced is argon and / or nitrogen with a purity of not less than 99.99%, and the gas flow rate is 0.3 liters / minute to 0.8 liters / minute. The hydrogen and other gases in the aluminum liquid are fully removed, and then the liquid surface is skimmed to remove the scum on the liquid surface to obtain the die-casting aluminum liquid.

[0105] Exemplarily, the speed of the degasser can be 150 rpm, 160 rpm, 180 rpm, 200 rpm, 250 rpm, 300 rpm, etc., typical but non-limiting arbitrary point values ​​or interval values ​​between any two points. The inert atmosphere can be nitrogen, argon, helium, etc. The gas flow rate can be 0.3 liters / minute, 0.4 liters / minute, 0.5 liters / minute, 0.6 liters / minute, 0.7 liters / minute, 0.8 liters / minute, etc., typical but non-limiting arbitrary point values ​​or interval values ​​between any two points. The degassing time can be 50 minutes, 52 minutes, 55 minutes, 58 minutes, 60 minutes, etc., typical but non-limiting arbitrary point values ​​or interval values ​​between any two points.

[0106] In some embodiments, after refining and degassing, the scum on the surface of the aluminum liquid is removed, and after standing for 15 to 25 minutes, a spectrum sample is taken to detect the composition. When the composition meets the requirements, the temperature of the aluminum liquid is lowered and set aside.

[0107] The aluminum alloy of the embodiment of the present application can be cast by any method in the art. For example, it can be cast under high pressure. In some possible implementations, a die-casting process is used for casting, and the die-casting process includes the following conditions: the liquid temperature of the aluminum alloy to be die-cast is 700°C to 710°C, the temperature of the mold temperature machine is 150°C to 170°C, the injection speed is 2.5m / s to 3.5m / s, and the boost pressure is 60Mpa to 65Mpa, and the die-casting is processed into specific parts. In some embodiments, after casting, post-processing processes such as trimming, dimensional inspection, and optional appropriate shaping can also be performed.

[0108] For example, the temperature of the die-casting aluminum liquid can be 700°C, 702°C, 704°C, 705°C, 707°C, 708°C, 709°C, 710°C, etc., typical but non-limiting arbitrary point values ​​or interval values ​​between any two point values, the temperature of the mold temperature machine can be 150°C, 155°C, 160°C, 165°C, 170°C, etc., typical but non-limiting arbitrary point values ​​or interval values ​​between any two point values, and the injection speed is 2.5m / s, 2.6m / s, etc. The boost pressure is any typical but non-restrictive point value or the interval value between any two point values, such as 60Mpa, 61Mpa, 62Mpa, 63Mpa, 64Mpa, 65Mpa, etc., which are typical but non-restrictive values.

[0109] On the third aspect, the embodiments of the present application provide an application of an aluminum alloy, wherein the above-mentioned aluminum alloy or the aluminum alloy prepared by the above-mentioned method is applied to at least one field of automobile, electronics industry, communication equipment, aerospace, and shipbuilding.

[0110] The aluminum alloy in the embodiment of the present application has good high pressure casting performance, reliable mechanical properties before and after brazing, and ensures the welding quality and appearance quality of the casting after welding, as well as the castability and service performance of the casting parts. Therefore, it can be widely used in the fields of automobiles, electronics industry, communication equipment, aerospace, shipbuilding, etc.

[0111] In some embodiments, the automobile includes a fuel vehicle, an electric vehicle, etc. In some specific embodiments, the aluminum alloy is applied to parts on the automobile such as parts in a thermal management fluid management system.

[0112] In order to enable the above implementation details and operations of the present application to be clearly understood by those skilled in the art, as well as to significantly demonstrate the improved performance of the aluminum alloy in the embodiments of the present application and its preparation method and application, the above technical scheme is illustrated by means of multiple embodiments below.

[0113] Example 1

[0114] An aluminum alloy comprises the following components in percentage by mass relative to the total weight of the aluminum alloy: 1.1% Fe, 0.93% Mn, 0.03% Si, 0.95% Mg, 0.87% Zn, and the remainder Al and unavoidable impurities.

[0115] Its preparation comprises the steps of:

[0116] 1. Material preparation: Material preparation is carried out according to the alloy composition ratio. Alloy elements are added in the form of pure alloy or master alloy. Among them, Al is added in the form of A00 industrial pure aluminum, Si is added in the form of elemental silicon, Mn is added in the form of Al-Mn master alloy, Sr is added in the form of Al-Sr rod master alloy, Fe is added in the form of Al-Fe master alloy, V is added in the form of Al-V master alloy, Mg is added in the form of Al-Mg master alloy, and Zn is added in the form of pure zinc ingot;

[0117] 2. Melting aluminum ingot: Place A00 and silicon into a resistance crucible for heating and melting, and control the temperature of the aluminum liquid between 720℃ and 740℃;

[0118] 3. Adding master alloy: When the temperature of aluminum liquid reaches 730℃~735℃, detect the composition in the furnace, add the required supplementary components, weigh the required master alloy and bake it, add the dried Al-Mn master alloy, Al-Fe master alloy, Al-Ti and other master alloys into the aluminum liquid, heat the aluminum liquid to 740℃~760℃, keep it warm for 10~30 minutes, and ensure that all the added master alloys are melted;

[0119] 4. Refining, modification and degassing: First, press the Al-Sr master alloy into the aluminum liquid, and use an iron rake to continuously stir the bottom without damaging the liquid surface. Repeat the action three times. After the stirring is completed, test whether the strontium content meets the requirements. After meeting the standard requirement of more than 10%, degas the aluminum liquid to remove hydrogen in the aluminum liquid. The control parameters are: the speed of the degasser is 150 rpm to 300 rpm, the gas introduced is high-purity argon or nitrogen with a purity of >99.99%, and the gas flow rate is 0.3 liters / minute to 0.8 liters / minute;

[0120] 5. Composition detection and cooling: After refining and degassing, remove the scum on the surface of the aluminum liquid. After standing for 15 to 25 minutes, take a spectrum sample to detect the composition. When the composition meets the requirements, lower the temperature of the aluminum liquid.

[0121] 6. Aluminum alloy is cast according to the die-casting process: the temperature of die-casting aluminum liquid is controlled at 700℃~710℃, the temperature of the mold temperature controller is controlled at 150℃~170℃, the die-casting speed is controlled at 2.5m / s~3.5m / s, and the boost pressure is 65Mpa. When processed into specific parts, trimming, size inspection and optional appropriate shaping are also carried out after casting.

[0122] Example 2

[0123] An aluminum alloy comprises the following components in percentage by weight relative to the total weight of the aluminum alloy: 0.91% Fe, 0.93% Mn, 0.03% Si, and the remainder Al and inevitable impurities. The preparation method thereof is the same as that of Example 1.

[0124] Example 3

[0125] An aluminum alloy comprises the following components in percentage by weight relative to the total weight of the aluminum alloy: 1.25% Fe, 1.66% Mn, 0.46% Si, 0.57% Sr, and the remainder Al and inevitable impurities. The preparation method thereof is the same as that of Example 1.

[0126] Example 4

[0127] An aluminum alloy comprises the following components in percentage by mass relative to the total weight of the aluminum alloy: 1.64% Fe, 1.72% Mn, 0.95% Si, 1.32% Sr, 0.18% V, and the remainder Al and unavoidable impurities. The preparation method thereof is the same as that of Example 1.

[0128] Example 5

[0129] An aluminum alloy comprises the following components in percentage by mass relative to the total weight of the aluminum alloy: 1.56% Fe, 1.67% Mn, 1.5% Si, 2.0% Sr, and the remainder Al and unavoidable impurities. The preparation method thereof is the same as that of Example 1.

[0130] Example 6

[0131] An aluminum alloy comprises the following components in percentage by weight relative to the total weight of the aluminum alloy: 1.56% Fe, 1.67% Mn, 0.66% Si, 1.04% Sr, and the remainder Al and unavoidable impurities. The preparation method thereof is the same as that of Example 1.

[0132] Comparative Example 1

[0133] An aluminum alloy comprises the following components in percentage by weight relative to the total weight of the aluminum alloy: 1.2% Fe, 1.0% Mn, 0.2% Si, and the remainder Al and inevitable impurities. The preparation method thereof is the same as that of Example 1.

[0134] Comparative Example 2

[0135] An aluminum alloy comprises the following components in percentage by weight relative to the total weight of the aluminum alloy: 1.51% Fe, 1.62% Mn, 0.92% Si, 0.8% Sr, and the remainder Al and unavoidable impurities. The preparation method thereof is the same as that of Example 1.

[0136] Comparative Example 3

[0137] An aluminum alloy comprises the following components in percentage by mass relative to the total weight of the aluminum alloy: 1.50% Fe, 1.8% Mn, 0.44% Si, 0.61% Sr, 0.2% Mg, and the remainder Al and unavoidable impurities. The preparation method thereof is the same as that of Example 1.

[0138] Comparative Example 4

[0139] An aluminum alloy comprises the following components in percentage by mass relative to the total weight of the aluminum alloy: 1.47% Fe, 1.82% Mn, 0.46% Si, 0.63% Sr, 0.2% Mg, 0.22% V, and the remainder being Al and unavoidable impurities. The preparation method thereof is the same as that of Example 1.

[0140] Comparative Example 5

[0141] An aluminum alloy comprises the following components in percentage by weight relative to the total weight of the aluminum alloy: 0.67% Fe, 0.78% Mn, 0.04% Si, and the remainder Al and inevitable impurities. The preparation method thereof is the same as that of Example 1.

[0142] Comparative Example 6

[0143] An aluminum alloy comprises the following components in percentage by weight relative to the total weight of the aluminum alloy: 1.5% Fe, 0.56% Mn, 0.07% Si, and the remainder Al and inevitable impurities. The preparation method thereof is the same as that of Example 1.

[0144] Comparative Example 7

[0145] An aluminum alloy comprises the following components in percentage by weight relative to the total weight of the aluminum alloy: 0.7% Fe, 1.81% Mn, 0.05% Si, and the remainder Al and inevitable impurities. The preparation method thereof is the same as that of Example 1.

[0146] The types and compositions of the metal elements in the aluminum alloys of the above-mentioned embodiments and comparative examples are shown in Table 1 below.

[0147] In order to verify the progress of the embodiments of the present application, the solidus temperature and die casting castability of the aluminum alloys of the above embodiments and comparative examples were tested respectively:

[0148] 1. Measurement of solidus temperature: using differential scanning calorimeter DSC;

[0149] The above test results are shown in Table 1 below:

[0150] Table 1

[0151]

[0152]

[0153] From the test results in Table 1 above, it can be seen that the aluminum alloy of the embodiment of the present application has excellent castability, and the solidus temperature is not less than 610°C, among which the solidus temperature of Embodiments 2 to 5 is not less than 640°C, and in particular, the solidus temperature of Embodiment 2 is as high as 651°C. The weldability of the aluminum alloy at conventional brazing temperatures (such as 600°C) can be improved, ensuring the castability and service performance of the cast parts.

[0154] In addition, the aluminum alloy die castings prepared in each embodiment and comparative example were subjected to brazing simulation under the same conditions: after being kept at 610°C for 15 minutes, the properties of the casting samples were tested. The following performance tests were performed on the aluminum alloy before and after brazing:

[0155] 1. Ultra tensile strength (UTS) test: GB / T 228.1-2010 "Tensile test of metallic materials Part 1: Room temperature test method";

[0156] 2. Yield strength (YS) test: GB / T 228.1-2010 "Tensile test of metallic materials Part 1: Room temperature test method";

[0157] 3. Elongation at break (EL) test: GB / T 228.1 "Metal Tensile Test Method";

[0158] The above test results are shown in Table 2 below:

[0159] Table 2

[0160]

[0161]

[0162] It can be seen from the test results in Table 2 above that the aluminum alloy in the embodiment of the present application ensures that the aluminum alloy has reliable mechanical properties before and after brazing by reasonably matching the content of each metal element in the alloy, thereby ensuring the castability and service performance of the aluminum alloy casting parts and improving the qualified rate of the casting parts.

[0163] In addition, Figure 2 This is a die-casting product of aluminum alloy in Example 1 of the present application. It can be seen that there is no cracking or mold strain at the sharp corners of the die-casting product, and the die-casting performance is good.

[0164] Attached Figure 3 This is the metallographic structure diagram of the aluminum alloy of Example 1 of the present application. It can be seen that the microstructure of the aluminum alloy is normal.

[0165] Attached Figure 4This is a solidification simulation test diagram of the aluminum alloy of Example 6 of the present application under non-equilibrium cooling conditions. It can be seen that the solidification phase transformation behavior of the aluminum alloy provided in the embodiment of the present application under cooling conditions is finally completed at 645.7°C.

[0166] Attached Figure 5 This is the aluminum-iron pseudo binary phase diagram of the aluminum alloy of Example 6 of the present application. Using the material computing tool Pandat software in the industry, the phase change law of the aluminum alloy of the present application example during the melting or solidification process is simulated as the Fe content changes. It can be seen that when the Fe content in the aluminum alloy is 0.7% to 2.0%, it has better performance.

[0167] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. An aluminum alloy, characterized in that: The aluminum alloy comprises the following components in percentage by weight relative to the total weight of the aluminum alloy: Fe is 0.7% to 2.0%, Mn is 0.6% to 2.0%, Si < 0.1%, Mg is 0 to 1%, Zn is 0 to 1%, and the balance is Al and unavoidable impurities; Alternatively, Fe is 0.7% to 2.0%, Mn is 0.6% to 2.0%, 0<Si<2.0%, 0<Sr<2.0%, V is 0 to 0.3%, Mg<0.2%, and the balance is Al and unavoidable impurities.

2. The aluminum alloy according to claim 1, characterized in that The aluminum alloy includes the following components in percentage by mass, relative to the total weight: Fe is 0.7% to 2.0%, Mn is 0.6% to 2.0%, Si is 0.01% to 2.0%, Sr is 0.01% to 2.0%, Mg is less than 0.1%, and the remainder is Al and unavoidable impurities.

3. The aluminum alloy according to claim 1, characterized in that The aluminum alloy includes the following components in percentage by mass, relative to the total weight: Fe is 0.7% to 2.0%, Mn is 0.6% to 2.0%, Si is 0.01% to 2.0%, Sr is 0.01% to 2.0%, V is 0.01% to 0.3%, Mg is less than 0.1%, and the remainder is Al and unavoidable impurities.

4. The aluminum alloy according to any one of claims 1 to 3, characterized in that When the aluminum alloy contains both Si and Sr, the Sr and Si elements satisfy the relationship: 22*Sr (wt.%) ≥ 30*Si (wt.%) -3; And / or, relative to the total weight of the aluminum alloy, comprising the following components in percentage by mass: Fe is 1.0% to 2.0%, Mn is 1.0% to 2.0%, Si is 0.4% to 1.5%, Sr is 0.5% to 2.0%, Mg is less than 0.1%, and the balance is Al and unavoidable impurities; Alternatively, based on the total weight of the aluminum alloy, the aluminum alloy includes the following components in percentage by mass: Fe is 1.0% to 2.0%, Mn is 1.0% to 2.0%, Si is 0.5% to 1.5%, Sr is 1% to 2.0%, V is 0.1% to 0.2%, Mg<0.1%, and the remainder is Al and unavoidable impurities.

5. The aluminum alloy according to claim 4, characterized in that The aluminum alloy comprises the following components in percentage by mass: 1.25% Fe, 1.66% Mn, 0.46% Si, 0.57% Sr, and the remainder Al and unavoidable impurities, relative to the total weight of the aluminum alloy; Alternatively, Fe is 1.64%, Mn is 1.72%, Si is 0.95%, Sr is 1.32%, V is 0.18%, and the balance is Al and unavoidable impurities; Alternatively, Fe is 1.56%, Mn is 1.67%, Si is 1.5%, Sr is 2.0%, and the balance is Al and unavoidable impurities; Alternatively, Fe is 1.56%, Mn is 1.67%, Si is 0.66%, Sr is 1.04%, and the balance is Al and inevitable impurities.

6. The aluminum alloy according to claim 1, characterized in that The aluminum alloy includes the following components in percentage by mass relative to the total weight: Fe is 0.9% to 1.5%, Mn is 0.6% to 1.5%, Si is less than 0.05%, Mg is 0 to 1%, Zn is 0 to 1%, and the remainder is Al and unavoidable impurities.

7. The aluminum alloy according to claim 1 or 6, characterized in that The aluminum alloy comprises the following components in percentage by mass: 1.1% Fe, 0.93% Mn, 0.03% Si, 0.95% Mg, 0.87% Zn, and the remainder Al and unavoidable impurities, relative to the total weight of the aluminum alloy; Alternatively, Fe is 0.91%, Mn is 0.93%, Si is 0.03%, and the balance is Al and inevitable impurities.

8. The aluminum alloy according to any one of claims 1 to 3, 5 or 6, characterized in that: The solidus temperature of the aluminum alloy is not less than 610°C.

9. A method for preparing an aluminum alloy, characterized in that: The following steps are involved: Obtaining a formulated amount of metal raw material components according to the aluminum alloy as described in any one of claims 1 to 8; Smelting the metal raw material components into alloy liquid; The alloy liquid is subjected to refining, degassing and slag removal treatments in sequence, and is formed into aluminum alloy parts.

10. An application of aluminum alloy, characterized in that: The aluminum alloy as claimed in any one of claims 1 to 8 or the aluminum alloy prepared by the method as claimed in any one of claims 9 is applied to at least one field of automobile, electronics industry, communication equipment, aerospace, and shipbuilding.

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