Cast aluminum-silicon alloy and preparation method and application thereof

Abstract

The invention provides a cast aluminum-silicon alloy and a preparation method and application thereof, and the cast aluminum-silicon alloy comprises the following element components in percentage by weight: greater than or equal to 7% and less than or equal to 9% of silicon, greater than or equal to 0.3% and less than or equal to 0.5% of magnesium, greater than or equal to 0.7% and less than or equal to 1.2% of copper, less than or equal to 0.2% of zinc, less than or equal to 0.2% of iron, greater than or equal to 0.2% and less than or equal to 0.4% of manganese, less than or equal to 0.2% of chromium, greater than or equal to 0.05% and less than or equal to 0.3% of zirconium, greater than or equal to 0.03% and less than or equal to 0.2% of titanium, less than or equal to 0.2% of strontium and the balance of aluminum and impurity elements, the total content of impurity elements is smaller than or equal to 0.15%, the content of a single impurity element is smaller than or equal to 0.05%, and the ratio of the weight percentage of copper to the weight percentage of magnesium is 2-3. According to the scheme, the problems of low strength and poor plasticity of the cast aluminum-silicon alloy in the prior art are solved by controlling the proportion of all the element components in the cast aluminum-silicon alloy.

Description

Technical Field

[0001] The present invention relates to the technical field of cast aluminum-silicon alloy materials, and in particular to a cast aluminum-silicon alloy and a preparation method and application thereof. Background Art

[0002] Cast aluminum silicon alloys are widely used in the machinery manufacturing industry due to their excellent casting and mechanical properties, especially in areas requiring lightweight and high strength. Traditional cast aluminum silicon alloys have low strength (tensile strength 280-320MPa, yield strength 250-280MPa) and poor plasticity (elongation 3-6%), which limits their widespread use in high-performance applications. In order to improve the strength of the material, the industry generally uses Mg2Si and Al2Cu as strengthening phases, but this strategy simultaneously reduces the plasticity of the alloy. At the same time, in order to promote the formation of these strengthening phases, it is often necessary to add higher levels of copper and some high-cost elements such as scandium (Sc), vanadium (V), molybdenum (Mo), yttrium (Y), etc., which not only increases the material cost, but also affects the casting processability and application range of the alloy.

[0003] Currently, no effective solution has been proposed to the problems of low strength and poor plasticity of cast aluminum-silicon alloys in the existing technology. Summary of the Invention

[0004] The main purpose of the present invention is to provide a cast aluminum-silicon alloy and a preparation method and application thereof, so as to solve the problems of low strength and poor plasticity of cast aluminum-silicon alloy in the prior art.

[0005] To achieve the above-mentioned object, according to one aspect of the present invention, a cast aluminum-silicon alloy is provided, wherein the weight percentages of the element components in the cast aluminum-silicon alloy are as follows: 7% ≤ silicon ≤ 9%, 0.3% ≤ magnesium ≤ 0.5%, 0.7% ≤ copper ≤ 1.2%, zinc ≤ 0.2%, iron ≤ 0.2%, 0.2% ≤ manganese ≤ 0.4%, chromium ≤ 0.2%, 0.05% ≤ zirconium ≤ 0.3%, 0.03% ≤ titanium ≤ 0.2%, strontium ≤ 0.2%, and the remainder are aluminum and impurity elements, wherein the total content of the impurity elements is ≤ 0.15%, the content of a single impurity element is ≤ 0.05%, and the weight percentage ratio of copper to magnesium is 2 to 3.

[0006] Furthermore, the weight percentage of each element component in the cast aluminum-silicon alloy is: 7.5% ≤ silicon ≤ 8.5%, 0.35% ≤ magnesium ≤ 0.45%, 0.8% ≤ copper ≤ 1.0%, zinc ≤ 0.2%, iron ≤ 0.15%, 0.3% ≤ manganese ≤ 0.4%, 0.05% ≤ chromium ≤ 0.12%, 0.05% ≤ zirconium ≤ 0.15%, 0.04% ≤ titanium ≤ 0.12%, 0.01% ≤ strontium ≤ 0.03% and the remainder of aluminum and impurity elements, wherein the total content of impurity elements is ≤ 0.15%, the content of a single impurity element is ≤ 0.05%, and the ratio of the weight percentages of copper and magnesium is 2.1 to 2.5.

[0007] Furthermore, scandium, vanadium, molybdenum and yttrium are not added to the cast aluminum silicon alloy.

[0008] According to another aspect of the present invention, an application of a cast aluminum-silicon alloy is provided. The cast aluminum-silicon alloy is the above-mentioned cast aluminum-silicon alloy, and the cast aluminum-silicon alloy is used for vehicle parts.

[0009] According to another aspect of the present invention, a method for preparing a cast aluminum-silicon alloy is provided, wherein the cast aluminum-silicon alloy is the above-mentioned cast aluminum-silicon alloy, and the preparation method comprises the following steps: adding a first raw material other than the aluminum-strontium alloy and the TCB alloy into a smelting furnace for smelting, and stirring the first raw material evenly after the first raw material is completely melted to obtain a first alloy melt; adding the aluminum-strontium alloy and the TCB alloy into the first alloy melt and stirring the mixture to obtain a second alloy melt; refining and degassing the first alloy melt and / or the second alloy melt; casting using the refined and degassed second alloy melt to obtain a casting; and heat treating the casting to obtain a target workpiece.

[0010] Furthermore, the weight percentage of the TCB alloy in the second alloy melt is 0.05% to 1.5%.

[0011] Furthermore, in the obtained casting, the weight proportion of the Al5Cu2Mg8Si6 phase is greater than the weight proportion of the Al2Cu phase, wherein the weight proportion of the Mg2Si phase is ≤0.1%.

[0012] Furthermore, the first alloy melt or the second alloy melt is subjected to refining and degassing, including: the target alloy melt after refining and degassing needs to be left to stand; after the target alloy melt has been left to stand for a preset period of time, slag removal is performed.

[0013] Furthermore, the smelting temperature is 700°C to 780°C, and / or the refining and degassing temperature is 680°C to 730°C.

[0014] Furthermore, after heat treatment, the tensile strength of the target workpiece is not less than 370 MPa, the yield strength is not less than 280 MPa, and the elongation after fracture is not less than 7%.

[0015] By applying the technical solution of the present invention, by controlling the content and ratio of copper, magnesium and silicon elements in the cast aluminum-silicon alloy, the efficient precipitation of Al5Cu2Mg8Si6 phase is promoted, and the Al5Cu2Mg8Si6 phase is successfully initiated as the main strengthening phase of the cast aluminum-silicon alloy. The interface bonding force between the Al5Cu2Mg8Si6 phase and the matrix aluminum is strong. Even when the alloy is subjected to external loads, the Al5Cu2Mg8Si6 phase is not easy to separate from the matrix, reducing the starting point of cracks and avoiding the occurrence of brittle fracture. Once the Al5Cu2Mg8Si6 When the Al2Cu2Mg8Si6 phase begins to precipitate, it will consume the elements used to form the brittle phase in the alloy, thereby suppressing the formation of traditional brittle phases (such as Mg2Si and Al2Cu phases) and avoiding the risk of reducing the plasticity of the alloy due to the increase of strengthening phases. In addition, the Al5Cu2Mg8Si6 phase is more likely to form stable and fine precipitates. These precipitates can be evenly distributed in the alloy matrix, effectively hindering the movement of other dislocations in the crystal, thereby improving the strength of the material. These precipitates are small in size and can reduce the negative impact on the plasticity of the alloy, thereby improving the plasticity of the alloy. In the above scheme, by controlling the ratio of each element component in the cast aluminum silicon alloy, the problem of low strength and poor plasticity of the cast aluminum silicon alloy in the prior art is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0017] Figure 1 The tensile stress-strain curves of the T6 state samples of Examples 1-3 and Comparative Examples 1-3 of the present invention are shown. DETAILED DESCRIPTION

[0018] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0019] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0020] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way are interchangeable where appropriate, so that the embodiments of the present application described herein can, for example, be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0021] Now, exemplary embodiments according to the present application will be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in a variety of different forms and should not be interpreted as being limited to the embodiments described herein. It should be understood that these embodiments are provided to make the disclosure of this application thorough and complete, and to fully convey the concepts of these exemplary embodiments to those of ordinary skill in the art. In the accompanying drawings, for the sake of clarity, the thickness of layers and regions may be exaggerated, and the same reference numerals are used to represent the same devices, and thus their descriptions will be omitted.

[0022] As analyzed in the background technology, the existing technology has the problem of low strength and poor plasticity of cast aluminum-silicon alloy. To solve this problem, the present invention provides a cast aluminum-silicon alloy and a preparation method and application thereof.

[0023] In a typical embodiment of the present application, a cast aluminum-silicon alloy is provided, in which the weight percentages of the element components in the cast aluminum-silicon alloy are: 7% ≤ silicon ≤ 9%, 0.3% ≤ magnesium ≤ 0.5%, 0.7% ≤ copper ≤ 1.2%, zinc ≤ 0.2%, iron ≤ 0.2%, 0.2% ≤ manganese ≤ 0.4%, chromium ≤ 0.2%, 0.05% ≤ zirconium ≤ 0.3%, 0.03% ≤ titanium ≤ 0.2%, strontium ≤ 0.2%, and the remainder of aluminum and impurity elements, wherein the total content of impurity elements is ≤ 0.15%, the content of a single impurity element is ≤ 0.05%, and the weight percentage ratio of copper to magnesium is 2 to 3.

[0024] In the embodiments of the present application, by controlling the content and ratio of copper, magnesium and silicon elements in the cast aluminum-silicon alloy, the efficient precipitation of Al5Cu2Mg8Si6 phase is promoted, and the Al5Cu2Mg8Si6 phase is successfully induced as the main strengthening phase of the cast aluminum-silicon alloy. The interface bonding force between the Al5Cu2Mg8Si6 phase and the matrix aluminum is strong. Even when the alloy is subjected to external loads, the Al5Cu2Mg8Si6 phase is not easy to separate from the matrix, reducing the starting point of the crack and avoiding the occurrence of brittle fracture. Once the Al5Cu2Mg8Si6 phase When precipitation begins, it consumes the elements used to form brittle phases in the alloy, thereby suppressing the formation of traditional brittle phases (such as Mg2Si and Al2Cu phases) and avoiding the risk of reducing the plasticity of the alloy due to the increase of strengthening phases. In addition, the Al5Cu2Mg8Si6 phase is more likely to form stable and fine precipitates. These precipitates can be evenly distributed in the alloy matrix, effectively hindering the movement of other dislocations in the crystal, thereby improving the strength of the material. These precipitates are small in size and can reduce the negative impact on the plasticity of the alloy, thereby improving the plasticity of the alloy. In the above scheme, by controlling the ratio of each element component in the cast aluminum silicon alloy, the problem of low strength and poor plasticity of the cast aluminum silicon alloy in the prior art is solved.

[0025] In one embodiment of the present application, the weight percentage of each element component in the cast aluminum-silicon alloy is: 7.5% ≤ silicon ≤ 8.5%, 0.35% ≤ magnesium ≤ 0.45%, 0.8% ≤ copper ≤ 1.0%, zinc ≤ 0.2%, iron ≤ 0.15%, 0.3% ≤ manganese ≤ 0.4%, 0.05% ≤ chromium ≤ 0.12%, 0.05% ≤ zirconium ≤ 0.15%, 0.04% ≤ titanium ≤ 0.12%, 0.01% ≤ strontium ≤ 0.03% and the remainder of aluminum and impurity elements, wherein the total content of impurity elements is ≤ 0.15%, the content of a single impurity element is ≤ 0.05%, and the ratio of the weight percentages of copper and magnesium is 2.1 to 2.5.

[0026] In the embodiments of the present application, precise control of the components of copper, magnesium and silicon can promote the efficient precipitation of Al5Cu2Mg8Si6 phase to improve the strength of the alloy, while avoiding the reduction of plasticity due to excessive Al2Cu phase content; precise control of the components of zirconium, titanium and strontium can effectively refine the grains, improve the casting properties of the alloy, reduce casting defects, and improve the dimensional accuracy and surface quality of the castings; precise control of the components of iron can reduce the formation of needle-shaped iron phases and further improve the plasticity and processing properties of the alloy.

[0027] In one embodiment of the present application, scandium, vanadium, molybdenum and yttrium are not added to the cast aluminum-silicon alloy.

[0028] In the embodiments of the present application, the copper content in the cast aluminum silicon alloy is no more than 1.2%, and high-cost scandium, vanadium, molybdenum, and yttrium are not added, thereby reducing the cost of the alloy. The cost of the alloy is comparable to that of traditional low-cost alloys ZL105 and ZL106, but the performance is better than the higher-cost ZL107 and ZL111 alloys.

[0029] It should be noted that ZL105 alloy is an Al-Si casting alloy with a Si content of about 7%. Sometimes it also contains a small amount of magnesium and other trace elements to improve the performance of the alloy. ZL105 alloy has good casting performance and high corrosion resistance. It is often used in the manufacture of automobile engine cylinder blocks, cylinder heads, pistons and other components because of its good thermal stability, especially maintaining good performance at high temperatures.

[0030] ZL106 alloy is an Al-Si casting alloy, but it contains a higher Si content than ZL105, typically in the 10-13% range, which contributes to the alloy's strength and hardness. ZL106 alloy also contains some magnesium, copper, and other trace elements to further enhance its mechanical properties. It is suitable for manufacturing parts requiring good wear resistance and high strength, such as engine pistons, connecting rods, and some structural components.

[0031] ZL107 alloy is an Al-Si-Cu casting alloy with a Cu content of about 3%. It also contains small amounts of Mg and Fe. ZL107 alloy has high strength and hardness and can be strengthened by heat treatment. It is suitable for manufacturing mechanical parts that withstand high stress, such as engine cylinders, pistons, brake drums and wheel hubs. Its mechanical properties are usually further improved through T6 heat treatment.

[0032] ZL111 alloy is an Al-Si-Cu alloy, but the Cu content is higher, up to about 4.5%. It also contains Mg (about 0.5%) and a small amount of Mn, Fe and other elements. ZL111 alloy has high strength and good wear resistance, can be strengthened by heat treatment, and is widely used in the manufacture of components with particularly high strength and reliability requirements, such as aircraft parts, automobile engines and high-strength components in transmission systems.

[0033] In a typical embodiment of the present application, an application of a cast aluminum-silicon alloy is provided. The cast aluminum-silicon alloy is the cast aluminum-silicon alloy in the above embodiment, and the cast aluminum-silicon alloy is used for vehicle parts.

[0034] The application scope of the cast aluminum-silicon alloy in this application is not limited to vehicle parts, but can be further extended to other industrial fields with high requirements for material strength, plasticity and corrosion resistance, including but not limited to: aviation engine parts and aircraft structures, hull structures and propulsion system components, laptop and mobile phone casings, bicycle frames, golf club heads, aluminum alloy window frames, curtain wall structures and precision machinery parts (such as gears, bearing seats), etc.

[0035] In a typical embodiment of the present application, a method for preparing a cast aluminum-silicon alloy is provided. The cast aluminum-silicon alloy is the cast aluminum-silicon alloy in the above embodiment. The preparation method comprises the following steps:

[0036] Step S1: adding a first raw material other than the aluminum-strontium alloy and the TCB alloy into a smelting furnace for smelting, and stirring the first raw material evenly after the first raw material is completely melted to obtain a first alloy melt.

[0037] Specifically, the first raw material refers to silicon, magnesium, copper, zinc, iron, manganese, chromium, zirconium, titanium, and the remainder of aluminum and impurity elements.

[0038] Step S2: adding the aluminum-strontium alloy and the TCB alloy to the first alloy melt and stirring them to obtain a second alloy melt.

[0039] Step S3: refining and degassing the first alloy melt and / or the second alloy melt.

[0040] Specifically, the first alloy melt can be refined and degassed before the aluminum-strontium alloy and TCB alloy are added to the first alloy melt; the second alloy melt can be refined and degassed after the aluminum-strontium alloy and TCB alloy are added to the first alloy melt; and the aluminum-strontium alloy and TCB alloy can also be added during the refining and degassing process of the first alloy melt.

[0041] Step S4: Casting is performed using the refined and degassed second alloy melt to obtain a casting.

[0042] Step S5: heat-treating the casting to obtain a target workpiece.

[0043] Specifically, the castings are heat treated using the T6 treatment process, which includes solution treatment and aging hardening. Aging hardening is a process in which the material is placed at a lower temperature (usually 120°C to 200°C) during the cooling process after solution treatment, allowing the solute atoms in the supersaturated solid solution to slowly diffuse and reaggregate to form fine precipitates. These precipitates can enhance the strength and hardness of the matrix without significantly damaging the toughness of the alloy.

[0044] In the embodiments of the present application, the first alloy melt with uniform composition helps to eliminate local composition inhomogeneities and reduce casting defects (such as cracks and shrinkage); the addition of aluminum strontium alloy can improve the thermodynamic properties of the alloy and optimize the phase morphology; the addition of TCB alloy helps to refine the grains and improve the microstructural quality of the alloy, thereby significantly improving the strength and toughness of the alloy; the secondary mixing ensures the uniformity of the distribution of alloy elements, creating favorable conditions for the subsequent refining and degassing steps; through refining and degassing, hydrogen and other non-metallic inclusions in the melt can be effectively removed, which is crucial for improving the purity of the alloy and reducing internal defects, and helps to improve the comprehensive mechanical properties of the alloy, especially fatigue strength and corrosion resistance; heat treatment can not only enhance the mechanical properties of the alloy, but also help to improve its corrosion resistance and welding performance, providing a guarantee for the long-term stability and functionality of the alloy in practical applications.

[0045] Preferably, the weight percentage of the TCB alloy in the second alloy melt is 0.05% to 1.5%.

[0046] The weight proportion of TCB alloy is controlled within the above range to maximize the effect of grain refinement, thereby improving the strength and plasticity of the alloy.

[0047] Furthermore, in the obtained casting, the weight proportion of the Al5Cu2Mg8Si6 phase is greater than the weight proportion of the Al2Cu phase, wherein the weight proportion of the Mg2Si phase is ≤0.1%.

[0048] By controlling the weight ratio of each element component in the cast aluminum-silicon alloy and the preparation conditions, the weight ratio of the precipitated Al5Cu2Mg8Si6 phase is greater than the weight ratio of the Al2Cu phase, and the weight ratio of the Mg2Si phase is limited to ≤0.1%. This helps to improve the strength and plasticity of the cast aluminum-silicon-copper-magnesium alloy and optimize costs.

[0049] In one embodiment of the present application, refining and degassing the first alloy melt or the second alloy melt includes: the target alloy melt after refining and degassing needs to be left to stand; after the target alloy melt has been left to stand for a preset period of time, slag removal is performed.

[0050] The comprehensive treatment of refining, degassing, standing and slag cleaning helps to form a denser and purer alloy melt. This high-quality melt can fill the mold more evenly during the casting process, forming a casting with uniform structure and no obvious holes and cracks, thereby improving the microstructure of the casting and enhancing its strength and toughness.

[0051] Furthermore, the smelting temperature is 700°C to 780°C, and / or the refining and degassing temperature is 680°C to 730°C.

[0052] By controlling the melting temperature and refining and degassing temperature within the above range, the deep purification and element homogenization of the alloy melt are effectively achieved, thereby significantly improving the microstructural quality of the casting and enhancing the comprehensive mechanical properties of the alloy, including high strength and high plasticity characteristics.

[0053] Furthermore, after heat treatment, the tensile strength of the target workpiece is not less than 370 MPa, the yield strength is not less than 280 MPa, and the elongation after fracture is not less than 7%.

[0054] The beneficial effects of the present application will be described below with reference to specific embodiments and comparative examples.

[0055] Example 1

[0056] Prepare the following elemental components in the following proportions by weight:

[0057] Silicon 7.5%, magnesium 0.38%, copper 0.89%, zinc ≤0.2%, manganese 0.30%, iron 0.08%, zirconium 0.1%, chromium 0.1%, strontium 0.020%, titanium 0.06%, the weight ratio of copper to magnesium is 2.3:1, the content of other individual impurities is ≤0.05%, the total content of other impurities is ≤0.15%, the balance is aluminum, and the TCB addition amount is 0.8% of the total weight of the melt.

[0058] Prepare raw materials according to the above elemental composition, put each raw material into the furnace in turn for melting at a melting temperature of 760°C; stir evenly after the alloy is completely melted, then add aluminum strontium alloy and TCB alloy and stir again, and then let it stand for 15 minutes; start the degassing refiner and add sodium-free refining agent, use argon and / or nitrogen to refine and degas the alloy liquid at 710°C, and refine and degas for 20 minutes. After refining, let it stand for 15 minutes to clear slag; then use the extrusion casting method to prepare samples from the refined and degassed alloy liquid; after the prepared samples are cooled to room temperature, they are subjected to T6 treatment, and the heat treatment parameters are as follows: solution parameters are 500°C, 6h (quenching water cooling, water temperature is 30°C); aging parameters are 160°C, 10h.

[0059] Example 2

[0060] The difference between Example 2 and Example 1 is that the heat treatment parameters are as follows: the solution parameters are 530° C., 6 h (quenching water cooling, water temperature 30° C.); and the aging parameters are 160° C., 8 h.

[0061] Example 3

[0062] The difference between Example 3 and Example 1 is that the element components are: silicon 8.4%, magnesium 0.45%, copper 0.93%, zinc ≤0.2%, manganese 0.40%, iron 0.12%, zirconium 0.06%, chromium 0.12%, strontium 0.016%, titanium 0.11%, the ratio of copper to magnesium is 2.1:1, the content of other individual impurities is ≤0.05%, the total content of other impurities is ≤0.15%, and the balance is aluminum; the amount of TCB added is 0.8% of the total weight of the melt.

[0063] Example 4

[0064] Prepare the following elemental components in the following proportions by weight:

[0065] Silicon 8.9%, magnesium 0.42%, copper 1.2%, zinc ≤0.2%, manganese 0.38%, iron 0.16%, zirconium 0.2%, chromium 0.18%, strontium 0.025%, titanium 0.18%, the ratio of copper to magnesium is 2.9:1, the content of other individual impurities is ≤0.05%, the total content of other impurities is ≤0.15%, the balance is aluminum, and the TCB addition amount is 0.8% of the total weight of the melt.

[0066] Prepare the raw materials according to the above elemental composition and place them into a furnace for smelting at 770°C. After the alloy is completely melted, stir evenly, then add the aluminum-strontium alloy and TCB alloy and stir again, then let it stand for 15 minutes. Start the degassing refiner and add a sodium-free refining agent. Refine and degas the alloy liquid with argon and / or nitrogen at 700°C for 20 minutes. After refining, let it stand for 20 minutes to remove slag. Then, use the squeeze casting method to prepare samples from the refined and degassed alloy liquid. After the prepared samples cool to room temperature, they are subjected to T6 treatment. Heat treatment parameters are as follows: solution temperature at 520°C for 6 hours (quenching in water at 30°C); aging parameters at 180°C for 4 hours.

[0067] Comparative Example 1

[0068] Prepare the following elemental components in the following proportions by weight:

[0069] Silicon 7.5%, magnesium 0.3%, copper 0.4%, zinc ≤0.2%, manganese 0.36%, iron 0.11%, zirconium 0.07%, chromium 0.09%, strontium 0.02%, titanium 0.05%, the ratio of copper to magnesium is 1.3:1, the content of other individual impurities is ≤0.05%, the total content of other impurities is ≤0.15%, the balance is aluminum, and the TCB addition amount is 0.5% of the total weight of the melt.

[0070] Prepare raw materials according to the above elemental composition, put each raw material into the furnace in turn for melting at a melting temperature of 770°C; stir evenly after the alloy is completely melted, then add aluminum strontium alloy and TCB alloy and stir again, and then let it stand for 15 minutes; start the degassing refiner and add sodium-free refining agent, use argon and / or nitrogen to refine and degas the aluminum liquid at 700°C for 20 minutes, and let it stand for 20 minutes to clear the slag after refining; then use the extrusion casting method to prepare samples from the refined and degassed alloy liquid; after the prepared samples are cooled to room temperature, they are subjected to T6 treatment, and the heat treatment parameters are as follows: solution parameters are 510°C, 5h (quenching water cooling, water temperature is 30°C); aging parameters are 160°C, 10h.

[0071] Comparative Example 2

[0072] Prepare the following elemental components in the following proportions by weight:

[0073] Silicon 8.5%, magnesium 1.0%, copper 2.0%, zinc ≤0.2%, manganese 0.35%, iron 0.11%, zirconium 0.11%, chromium 0.10%, strontium 0.018%, titanium 0.08%, the ratio of copper to magnesium is 2.0:1, the content of other individual impurities is ≤0.05%, the total content of other impurities is ≤0.15%, the balance is aluminum, and the TCB addition amount is 0.8% of the total weight of the melt.

[0074] Prepare raw materials according to the above elemental composition, put each raw material into the furnace in turn for melting at a melting temperature of 770°C; stir evenly after the alloy is completely melted, then add aluminum strontium alloy and TCB alloy and stir again, and then let it stand for 15 minutes; start the degassing refiner and add sodium-free refining agent, use argon and / or nitrogen to refine and degas the alloy liquid at 710°C, and refine and degas for 20 minutes. After refining, let it stand for 15 minutes to clear the slag; then use the extrusion casting method to prepare samples from the refined and degassed alloy liquid; after the prepared samples are cooled to room temperature, they are subjected to T6 treatment, and the heat treatment parameters are as follows: solid solution parameters are 520°C, 6h (quenching water cooling, water temperature 30°C); aging parameters are 170°C, 8h.

[0075] Comparative Example 3

[0076] Prepare the following elemental components in the following proportions by weight:

[0077] Silicon 7.9%; Magnesium 0.45%; Copper 0.2%; Zinc ≤0.2%; Manganese 0.33%; Iron 0.2%; Zirconium 0.09%; Chromium 0.10%; Strontium 0.02%; Titanium 0.14%, the ratio of copper to magnesium is 0.4:1, the content of other individual impurities is ≤0.05%, the total content of other impurities is ≤0.15%, the balance is aluminum, and the TCB addition amount is 0.8% of the total weight of the melt.

[0078] Prepare the raw materials according to the above elemental composition and place them in a furnace for smelting at 760°C. Once the alloy is completely melted, stir evenly, then add the aluminum-strontium alloy and stir again, then let it stand for 15 minutes. Start the degassing refiner and add a sodium-free refining agent. Refine and degas the aluminum liquid with argon and / or nitrogen at 700°C for 20 minutes. After refining, let it stand for 20 minutes to remove slag. Then, use the squeeze casting method to prepare samples from the refined and degassed alloy liquid. After the prepared samples cool to room temperature, they are subjected to T6 treatment. Heat treatment parameters are as follows: solution temperature at 510°C for 8 hours (quenching in water at 30°C); aging parameters at 170°C for 8 hours.

[0079] Comparative Example 4

[0080] Prepare the following elemental components in the following proportions by weight:

[0081] Silicon 7.50%, magnesium 0.35%, copper 2.0%, zinc ≤0.2%, manganese 0.30%, iron 0.08%, zirconium 0.14%, chromium 0.11%, strontium 0.010%, titanium 0.042%, the ratio of copper to magnesium is 5.7:1, the total content of other impurities is ≤0.15%, and the content of a single impurity is ≤0.05%, the balance is aluminum, and the TCB addition amount is 0.5% of the total weight of the melt.

[0082] Prepare raw materials according to the above components, and put all raw materials except aluminum strontium alloy and TCB alloy into the furnace in turn for melting at a melting temperature of 780°C; after the alloy is melted evenly and completely, add aluminum strontium alloy and TCB alloy accounting for 0.5% of the total weight of the melt, then stir and let it stand for 10 minutes; start the degassing refining machine and add 0.5% of the weight of the molten aluminum liquid sodium-free refining agent, refine and degas the aluminum liquid with nitrogen at 700°C for 15 minutes, let it stand for 20 minutes after the refining is completed, and clean the slag; prepare the sample by squeeze casting process; after the prepared sample is cooled to room temperature, it is subjected to T6 treatment, and the heat treatment parameters are as follows: solution parameters are 500°C, 6h (quenching water cooling, water temperature is 30°C); aging parameters are 160°C, 10h.

[0083] The cast aluminum-silicon alloys obtained in Examples 1 to 4 and the aluminum-silicon alloys obtained in Comparative Examples 1 to 4 were respectively subjected to as-cast mechanical property tests, and the test results are listed in Table 1.

[0084] From Table 1 and Figure 1 It can be seen that compared to the comparative examples, the examples in this application maintain relatively high tensile strength (≥310 MPa) and yield strength (≥180 MPa) while also having high elongation (≥7%). Comparative Examples 2 and 4, while having high tensile strength and yield strength, have low elongation of only around 5%. Furthermore, the high Cu content (2%) of these two alloys may increase costs, affecting their application.

[0085] Table 1

[0086]

[0087] The casting aluminum-silicon alloys obtained in Examples 1 to 4 and the aluminum-silicon alloys obtained in Comparative Examples 1 to 4 were respectively subjected to T6 state mechanical property tests, and the test results are listed in Table 2.

[0088] From Table 2 and Figure 1 It can be seen that compared to the comparative examples, the cast aluminum-silicon alloys in each embodiment of this application have a tensile strength of ≥370 MPa, a yield strength of ≥280 MPa, and an elongation of ≥7% after T6 treatment. Specifically, after T6 treatment, the alloys of Examples 1 to 3 have a tensile strength of ≥380 MPa and an elongation of ≥8%, demonstrating excellent strength-ductility properties. The alloy of Comparative Example 1 has a high elongation, but low tensile strength and yield strength; while the alloys of Comparative Examples 2 and 4 have high strength, low elongation and are prone to brittle fracture; the alloy of Comparative Example 3 has both low strength and elongation.

[0089] Table 2

[0090]

[0091] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0092] By controlling the content and ratio of copper, magnesium, and silicon in the cast aluminum-silicon alloy, the efficient precipitation of the Al5Cu2Mg8Si6 phase is promoted, successfully inducing the Al5Cu2Mg8Si6 phase as the primary strengthening phase in the cast aluminum-silicon alloy. The Al5Cu2Mg8Si6 phase has a strong interfacial bonding with the aluminum matrix, and even when the alloy is subjected to external loads, the Al5Cu2Mg8Si6 phase is not easily separated from the matrix, reducing the initiation points of cracks and avoiding the occurrence of brittle fracture. Once the Al5Cu2Mg8Si6 phase begins to precipitate, it consumes the elements in the alloy that form brittle phases, thereby suppressing the formation of traditional brittle phases (such as Mg2Si and Al2Cu phases) and avoiding the risk of reduced alloy plasticity due to an increase in strengthening phases. In addition, the Al5Cu2Mg8Si6 phase is more likely to form stable and fine precipitates. These precipitates can be evenly distributed in the alloy matrix, effectively hindering the movement of other dislocations in the crystal, thereby improving the material's strength. The small size of these precipitates can reduce the negative impact on the alloy's plasticity, thereby improving the alloy's plasticity. By controlling the ratio of each element component in the cast aluminum-silicon alloy, the problems of low strength and poor plasticity of the cast aluminum-silicon alloy in the prior art are solved.

[0093] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0094] In addition to the above, it should be noted that references to "one embodiment," "another embodiment," "an embodiment," and the like in this specification refer to specific features, structures, or characteristics described in conjunction with that embodiment as included in at least one embodiment generally described in this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in conjunction with any embodiment, it is intended that such feature, structure, or characteristic, when implemented in conjunction with other embodiments, also falls within the scope of the present invention.

[0095] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0096] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A cast aluminum-silicon alloy, characterized in that: The weight percentages of the element components in the cast aluminum-silicon alloy are: 7% ≤ silicon ≤ 9%, 0.3% ≤ magnesium ≤ 0.5%, 0.7% ≤ copper ≤ 1.2%, zinc ≤ 0.2%, iron ≤ 0.2%, 0.2% ≤ manganese ≤ 0.4%, chromium ≤ 0.2%, 0.05% ≤ zirconium ≤ 0.3%, 0.03% ≤ titanium ≤ 0.2%, strontium ≤ 0.2%, and the remainder of aluminum and impurity elements, wherein the total content of impurity elements is ≤ 0.15%, the content of a single impurity element is ≤ 0.05%, and the weight percentage ratio of copper to magnesium is 2 to 3.

2. The cast aluminum-silicon alloy according to claim 1, characterized in that The weight percentages of the element components in the cast aluminum-silicon alloy are: 7.5%≤silicon≤8.5%, 0.35%≤magnesium≤0.45%, 0.8%≤copper≤1.0%, zinc≤0.2%, iron≤0.15%, 0.3%≤manganese≤0.4%, 0.05%≤chromium≤0.12%, 0.05%≤zirconium≤0.15%, 0.04%≤titanium≤0.12%, 0.01%≤strontium≤0.03%, and the remainder are aluminum and impurity elements, wherein the total content of impurity elements is ≤0.15%, the content of a single impurity element is ≤0.05%, and the weight percentage ratio of copper to magnesium is 2.1-2.

5.

3. The cast aluminum-silicon alloy according to claim 1 or 2, characterized in that: Scandium, vanadium, molybdenum and yttrium are not added to the cast aluminum silicon alloy.

4. An application of a cast aluminum-silicon alloy, wherein the cast aluminum-silicon alloy is the cast aluminum-silicon alloy according to any one of claims 1 to 3, characterized in that: The cast aluminum-silicon alloy is used for parts of vehicles.

5. A method for preparing a cast aluminum-silicon alloy, wherein the cast aluminum-silicon alloy is the cast aluminum-silicon alloy according to any one of claims 1 to 3, characterized in that: The preparation method comprises the following steps: adding a first raw material other than the aluminum-strontium alloy and the TCB alloy into a smelting furnace for smelting, and stirring the first raw material evenly after the first raw material is completely melted to obtain a first alloy melt; adding the aluminum-strontium alloy and the TCB alloy to the first alloy melt and stirring to obtain a second alloy melt; refining and degassing the first alloy melt and / or the second alloy melt; Casting the refined and degassed second alloy melt to obtain a casting; The casting is heat treated to obtain a target workpiece.

6. The preparation method according to claim 5, characterized in that The weight percentage of the TCB alloy in the second alloy melt is 0.05% to 1.5%.

7. The preparation method according to claim 5, characterized in that In the obtained casting, the weight proportion of the Al5Cu2Mg8Si6 phase is greater than the weight proportion of the Al2Cu phase, wherein the weight proportion of the Mg2Si phase is ≤0.1%.

8. The preparation method according to claim 5, characterized in that Refining and degassing the first alloy melt or the second alloy melt includes: The target alloy melt that has completed refining and degassing needs to be left to stand; After the target alloy melt is left to stand for a preset period of time, slag removal is performed.

9. The preparation method according to claim 5, characterized in that The smelting temperature is 700°C to 780°C, and / or the refining and degassing temperature is 680°C to 730°C.

10. The preparation method according to claim 5, characterized in that The target workpiece has a tensile strength of not less than 370 MPa, a yield strength of not less than 280 MPa, and an elongation after fracture of not less than 7%.

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