High-heat-transfer aluminum oxide die-casting material and preparation method thereof

Abstract

The invention provides a high-heat-transfer aluminum oxide die-casting material and a preparation method thereof, and belongs to the technical field of alloy materials. By optimizing components and process design, the compromise contradiction between heat conduction and mechanical properties of traditional aluminum alloy is broken through, and the provided aluminum alloy has excellent mechanical properties, good heat conduction performance, excellent corrosion resistance and casting forming performance; the die-casting die can be widely applied to electronic equipment, automobile engines or other equipment with high heat dissipation requirements in the industrial production field and other scenes with strict heat management requirements, and meanwhile is suitable for precise die-casting forming of complex thin-wall parts. According to the material, the heat dissipation efficiency of the material, the equipment reliability and the lightweight level are remarkably improved, and a key material support is provided for energy conservation, consumption reduction and technical innovation of the high-end manufacturing industry.

Description

Technical Field

[0001] The present invention relates to the technical field of alloy materials, and in particular to a high heat transfer oxidizable aluminum die-casting material and a preparation method thereof. Background Art

[0002] Aluminum alloys are lightweight metal materials based on aluminum, formed by adding various alloying elements (such as silicon, magnesium, and manganese). Due to their excellent specific strength, corrosion resistance, and processability, aluminum alloys are widely used in the automotive, aerospace, electronics, and heat exchange systems industries. As modern industry demands increased material performance, the research and development of aluminum alloys has gradually shifted towards multifunctionality. In particular, the coordinated optimization of high thermal conductivity, mechanical properties, and formability has become a key topic in materials science.

[0003] Thermal conductivity is a core indicator for measuring a material's heat transfer efficiency, directly affecting its application effectiveness in thermal management scenarios (such as heat sinks, electronic packaging, and energy equipment). The thermal conductivity of metal materials is primarily determined by lattice vibrations (phonon transfer) and free electron motion, while the thermal conductivity of aluminum alloys is closely related to their purity, grain boundary structure, and the types of alloying elements. However, when pursuing high strength or corrosion resistance, traditional aluminum alloys often add excessive alloying elements, resulting in lattice distortion or an increase in impurity phases, which significantly reduces thermal conductivity. Therefore, how to improve the thermal conductivity of aluminum alloys while maintaining mechanical properties has become a key challenge in material design.

[0004] From a microstructural perspective, the thermal conductivity of aluminum alloys is affected by the combined effects of solid solution atoms, second-phase particles, and grain boundary density. For example, the addition of silicon (Si) can improve the casting fluidity of the alloy, but excessive solid solution silicon will hinder electron migration; magnesium (Mg) can improve strength through solid solution strengthening, but it may increase the density of lattice defects and weaken the continuity of the thermal conductivity path. At the same time, industrial applications have put forward more stringent comprehensive requirements for aluminum alloys: they must meet the precision casting requirements of complex structural parts (such as the formability of thin-walled parts), and maintain long-term stability in high heat flux environments (such as oxidation resistance). In order to transform theoretical results into industrial materials that can be produced on a large scale, practical problems such as precise composition control, process stability, and cost-effectiveness still need to be solved.

[0005] Improving the thermal conductivity of aluminum alloys is an inevitable requirement for energy conservation and emission reduction, miniaturization of electronic devices, and improved energy efficiency. By breaking through the traditional composition-performance trade-off, the development of new aluminum alloys that combine high thermal conductivity, excellent mechanical properties, and reliable corrosion resistance not only has important scientific value but also provides key material support for high-end manufacturing. Summary of the Invention

[0006] The present invention aims to provide a high heat transfer oxidizable aluminum die-casting material and a preparation method thereof, which have excellent performance.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions: The present invention provides an aluminum alloy, wherein the chemical composition of the aluminum alloy includes Si 10.5% to 13.6%, Fe 0.9% to 1.12%, Cu ≤ 0.12%, Mn 0.21% to 0.56%, Mg 0.21% to 0.52%, Ni ≤ 0.15%, Zn ≤ 0.16%, Ti ≤ 0.15, and the balance is Al and other elements except the above elements, and the total amount of other elements is less than 0.1%.

[0008] Preferably, the chemical composition of the aluminum alloy includes Si 10.5%~13.6%, Fe 0.9%~1.12%, Cu≤0.12%, Mn 0.21%~0.56%, Mg 0.21%~0.52%, Ni≤0.15%, Zn≤0.16%, Ti≤0.15, and the balance is Al.

[0009] Preferably, the mass percentage content of Si and Cu satisfies 10.5%≤Si+Cu≤13.72%.

[0010] The present invention also provides a method for preparing the above-mentioned aluminum alloy, comprising the following steps: Aluminum alloy and / or pure metal containing Al, Si, Fe, Cu, Mn, Mg, Ni, Zn and Ti in required proportions are weighed according to the element ratio in the aluminum alloy, and the aluminum alloy is obtained by melting and die-casting.

[0011] The present invention also provides another method for preparing the above-mentioned aluminum alloy, comprising the following steps: Melting pure Al raw materials to obtain aluminum liquid; mixing aluminum liquid with raw materials containing Si, Fe, Cu, Mn and Zn to obtain a first melt; mixing the first melt, Mg and Ti to obtain a second melt; refining the second melt to obtain an aluminum alloy melt; pouring the aluminum alloy melt into an aluminum ingot mold to obtain an aluminum alloy ingot; The aluminum alloy ingot is subjected to heat shaping treatment to be made into a thin plate die casting to obtain an aluminum alloy.

[0012] Preferably, the melting comprises first heating the pure Al raw material to 200-230° C., preheating for 3-5 hours, then heating to 700-780° C., and keeping warm for 30-40 minutes.

[0013] Preferably, the ambient temperature for mixing the first melt, Mg and Ti is 700-760°C.

[0014] Preferably, the second melt is degassed by introducing an inert gas for 20 to 30 minutes before refining.

[0015] Preferably, the temperature of the heat shaping treatment is 250-280°C.

[0016] Preferably, the heat shaping treatment time is 10 to 20 seconds.

[0017] Beneficial effects of the present invention: The present invention provides a high-heat-conductivity, oxidizable aluminum die-casting material. This aluminum alloy has excellent mechanical properties, good thermal conductivity, excellent corrosion resistance, and casting formability. The synergistic improvement of its high thermal conductivity, high strength, and corrosion resistance makes it widely applicable to electronic equipment, automotive engines, or other industrial production fields with high heat dissipation requirements, and other scenarios with strict thermal management requirements. It is also suitable for the precision die-casting of complex thin-walled parts. By optimizing the composition and process design, this material breaks through the compromise between the thermal conductivity and mechanical properties of traditional aluminum alloys, significantly improving the material's heat dissipation efficiency, equipment reliability, and lightweight level, providing key material support for energy conservation and consumption reduction and technological innovation in the high-end manufacturing industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1-1 is the temperature-phase composition diagram; Figure 1-2 It is the aluminum-silicon binary phase diagram; Figure 2-1 is the density of QH01 aluminum alloy at different temperatures; Figure 2-2 is the Young's modulus of QH01 aluminum alloy at different temperatures; Figure 2-3 Mechanical properties of QH01 aluminum alloy; Figure 2-4 is the enthalpy of QH01 aluminum alloy at different temperatures; Figure 2-5 is the specific heat capacity of QH01 aluminum alloy at different temperatures; Figure 2-6 is the thermal conductivity of QH01 aluminum alloy at different temperatures; Figure 2-7 is the heat transfer coefficient of QH01 aluminum alloy at different temperatures. DETAILED DESCRIPTION

[0019] The present invention provides an aluminum alloy, the chemical composition of which includes Si 10.5% to 13.6%, Fe 0.9% to 1.12%, Cu ≤ 0.12%, Mn 0.21% to 0.56%, Mg 0.21% to 0.52%, Ni ≤ 0.15%, Zn ≤ 0.16%, Ti ≤ 0.15%, and the balance is Al and other elements other than the above elements, with the total amount of other elements being less than 0.1%. In the present invention, preferably, the chemical composition of the aluminum alloy includes Si 10.5% to 13.6%, Fe 0.9% to 1.12%, Cu ≤ 0.12%, Mn 0.21% to 0.56%, Mg 0.21% to 0.52%, Ni ≤ 0.15%, Zn ≤ 0.16%, Ti ≤ 0.15%, and the balance is Al. Preferably, the mass percentage content of Si and Cu satisfies 10.5% ≤ Si + Cu ≤ 13.72%.

[0020] The present invention also provides a method for preparing the above-mentioned aluminum alloy, comprising the following steps: weighing the required proportions of aluminum alloy and / or pure metal containing Al, Si, Fe, Cu, Mn, Mg, Ni, Zn and Ti according to the element ratio in the aluminum alloy, and melting and die-casting to obtain the die-cast aluminum alloy.

[0021] The present invention also provides another method for preparing the above-mentioned aluminum alloy, comprising the following steps: Pure Al raw material is melted (the desired proportions are weighed according to the elemental ratios in the aluminum alloy) to produce molten aluminum; the molten aluminum is mixed with raw materials containing Si, Fe, Cu, Mn, and Zn (the desired proportions are weighed according to the elemental ratios in the aluminum alloy) to produce a first melt; the first melt is mixed with Mg and Ti (the desired proportions are weighed according to the elemental ratios in the aluminum alloy) to produce a second melt; the second melt is refined to produce an aluminum alloy melt; the aluminum alloy melt is poured into an aluminum ingot mold to produce an aluminum alloy ingot; the aluminum alloy ingot is heat-formed to produce a thin sheet die-casting to produce the aluminum alloy. Preferably, the melting process includes first heating the pure Al raw material to 200-230°C, preheating for 3-5 hours, then heating to 700-780°C, and holding at this temperature for 30-40 minutes. Preferably, the ambient temperature for mixing the first melt, Mg, and Ti is 700-760°C. Preferably, the second melt is degassed by introducing an inert gas for 20 to 30 minutes before refining. Preferably, the temperature of the heat shaping treatment is 250 to 280° C. Preferably, the time of the heat shaping treatment is 10 to 20 seconds.

[0022] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0023] The chemical composition of the aluminum alloy provided by the present invention is shown in Table 1: Table 1 Chemical composition of aluminum alloy (wt.%)

[0024] In the table, BAL refers to the balance aluminum (Al) content.

[0025] Example 1 Chemical composition of the obtained aluminum alloy (wt.%): Si: 12.05%, Fe: 1.01%, Cu: 0.06%, Mn: 0.385%, Mg: 0.365%, Ni: 0.075%, Zn: 0.08%, Ti: 0.075%, Al: balance (85.91%), the total of other elements is <0.1%.

[0026] Preparation method: Weigh pure aluminum ingots, place them in a melting furnace and heat to 215°C for 3 hours; Raise the temperature to 740°C and keep it at that temperature for 35 minutes to form aluminum liquid; Si, Fe, Cu, Mn, and Zn are sequentially added to the aluminum liquid and stirred until completely melted to obtain a first melt; The temperature of the first melt was adjusted to 750°C, Mg and Ti were added, and the mixture was stirred and mixed to obtain a second melt; Argon was introduced into the bottom of the second melt for degassing for 25 minutes, and then a refining agent was added for refining; After refining, the mixture was allowed to stand for 60 minutes and the surface scum was removed to obtain a clean aluminum alloy melt. The melt is kept at 710°C, cast into a preheated aluminum ingot mold, and cooled to obtain an aluminum alloy ingot; The aluminum alloy ingots were die-cast into thin plates, which were then heat-formed at 265°C for 14 seconds and left to stand naturally for 44 hours.

[0027] Example 2 Ingredients (wt.%): Si: 11.30%, Fe: 0.95%, Cu: 0.10%, Mn: 0.30%, Mg: 0.25%, Ni: 0.12%, Zn: 0.12%, Ti: 0.10%, Al: balance (86.76%), the total of other elements is <0.1%.

[0028] Preparation method: Weigh pure aluminum ingots, place them in a melting furnace and heat to 225°C for 3 hours; Raise the temperature to 720°C and keep it at that temperature for 30 minutes to form aluminum liquid; Si, Fe, Cu, Mn, and Zn are sequentially added to the aluminum liquid and stirred until completely melted to obtain a first melt; The temperature of the first melt was adjusted to 735°C, Mg and Ti were added, and the mixture was stirred and mixed to obtain a second melt; Argon was introduced into the bottom of the second melt for degassing for 20 minutes, and then a refining agent was added for refining; After refining, the mixture was allowed to stand for 60 minutes and the surface scum was removed to obtain a clean aluminum alloy melt. The melt is kept at 680°C, cast into a preheated aluminum ingot mold, and cooled to obtain an aluminum alloy ingot; The aluminum alloy ingots were die-cast into thin plates, which were then heat-formed at 255°C for 13 seconds and then left to stand naturally for 46 hours.

[0029] Example 3 Ingredients (wt.%): Si: 13.50%, Fe: 1.10%, Cu: 0.12%, Mn: 0.50%, Mg: 0.50%, Ni: 0.15%, Zn: 0.16%, Ti: 0.15%, Al: balance (83.82%), the total of other elements is <0.1%.

[0030] Preparation method: Weigh pure aluminum ingots, place them in a melting furnace and heat to 230°C for 3 hours; Raise the temperature to 770°C and keep it at that temperature for 40 minutes to form aluminum liquid; Si, Fe, Cu, Mn, and Zn are sequentially added to the aluminum liquid and stirred until completely melted to obtain a first melt; The temperature of the first melt was adjusted to 760°C, Mg and Ti were added, and the mixture was stirred and mixed to obtain a second melt; Argon was introduced into the bottom of the second melt for degassing for 30 minutes, and then a refining agent was added for refining; After refining, the mixture was allowed to stand for 70 minutes and the surface scum was removed to obtain a clean aluminum alloy melt. The melt is kept at 720°C, cast into a preheated aluminum ingot mold, and cooled to obtain an aluminum alloy ingot; The aluminum alloy ingots were die-cast into thin plates, which were then heat-formed at 275°C for 17 seconds and then left to stand naturally for 47 hours.

[0031] Experimental example 1. The simulation of mechanical properties primarily considers two strengthening mechanisms: solid solution strengthening via solute atoms and strengthening via second-phase particles. The simulation of solid solution strengthening is similar to the calculation of solid solution properties.

[0032] Among them, precipitation strengthening can be considered from the following two situations: For small particle sizes, the strengthening effect on the yield strength of the alloy can be measured using the following equation: (1-1) Where: YS1——alloy yield strength and lattice yield strength; YS0 - alloy lattice yield strength; M——Taylor coefficient; b——Burgers vector; A – shape factor constant; d——precipitated particle diameter; τ——Linear tension of dislocation f——represents the volume fraction of tiny particles; γ——is the APB energy.

[0033] For large particles, the strengthening effect can be measured using the following equation: (1-2) Where: ω is the constant indicating the repulsive force between dislocations within the precipitate.

[0034] ω is a constant that indicates the repulsion between dislocations within the precipitate and is actually an empirical coefficient. During calculations, the appropriate model can be automatically matched based on the changes in stress and temperature, and then the mechanical properties can be calculated by combining them.

[0035] Material simulation calculation can use thermodynamic models and thermodynamic data as core technology and calculation basis to calculate various properties of metal materials, such as mechanical properties, thermophysical properties, thermodynamic phase diagrams, etc. Figure 1-1 、 Figure 1-2 shown.

[0036] 2. Thermal performance is a key material property and a prerequisite for ensuring its application. Thermal performance refers to the thermophysical properties of materials and their products, which react to varying temperatures during use. Thermal properties include heat capacity, thermal expansion, thermal conductivity, and thermal stability.

[0037] According to the principles of thermodynamics, the phase composition under equilibrium conditions is calculated: (1-3) The left side of the equation is the molar Gibbs free energy of each phase, the first term on the right side is the Gibbs free energy of the pure component, the second term on the right side is the free energy increase caused by the ideal mixing entropy, and the third term is the excess free energy caused by the deviation from the ideal solution. is the interaction coefficient.

[0038] Calculate the relevant properties of each phase based on its alloy composition: (1-4) The overall properties of the material are calculated using the law of mixtures based on the phase composition of the material and the properties of each phase: (1-5) QH01 aluminum alloy samples were obtained using the sand casting method described in Example 1. The as-cast aluminum alloy was treated using the T6 heat treatment process. The material properties of the QH01 aluminum alloy were simulated using this process flow and relevant parameters. The curing temperature was set at 530°C, and the aging temperature was set at 200°C. The microstructural evolution and precipitation formation during the heat treatment were simulated to predict the mechanical properties after treatment.

[0039] Based on the results of the casting and heat treatment process parameter simulation, the tensile strength of QH01 aluminum alloy at room temperature was predicted to be 243.11 MPa, which is close to the tensile strength of the actual processed workpiece of 243 MPa.

[0040] In the solidification calculation, parameters were set to simulate the solidification process of QH01 aluminum alloy. Particular attention was paid to the material properties when the residual liquid fraction during solidification was 0.1%. All phases, including solid solutions, intermediate phases, and intermetallic compounds, were considered to ensure simulation accuracy.

[0041] Through simulation, the predicted values of density, Young's modulus, yield strength, hardness and tensile strength of QH01 aluminum alloy in a specific solidification state are obtained. Figure 2-1 、 Figure 2-2 and Figure 2-3 The density at room temperature is 2.69 g / cm³, the Young's modulus is 80.1802 GPa, and at an initial cooling rate of 5°C / s, the yield strength is 146.38 MPa, the hardness HBW is 77.71, and the tensile strength is 242.82. These predicted values take into account the mechanical properties of different phases, the interactions between them, and the effects of the microstructure.

[0042] 3. In addition, the yield strength, tensile strength, and hardness of the QH01 aluminum alloy obtained through simulation are close to the actual measured values, as shown in Table 2, thus verifying the feasibility of the simulation. This result provides strong support for the prediction of material properties through simulation.

[0043] Table 2 Comparison of simulated values and actual measured values

[0044] Thermophysical properties When selecting simulation calculation conditions, choose to calculate thermal properties under equilibrium conditions. This condition assumes that the material has reached thermal equilibrium at each temperature point, thus more accurately reflecting the material's thermal properties. Enter the Thermal Properties Calculation module, set the initial temperature to 560°C, the final temperature to 0°C, and the temperature gradient to 5°C. After setting the calculation parameters, perform the corresponding simulation. Based on the set temperature range and gradient, the enthalpy, specific heat capacity, and thermal conductivity of the QH01 aluminum alloy are calculated step by step at each temperature point.

[0045] In the calculation process, the influence of factors such as the chemical composition, phase composition and microstructure of the material on the thermal properties is considered. Through the data in the database, the enthalpy, specific heat capacity and thermal conductivity of the material at different temperatures can be predicted. The results are as follows Figure 2-4 、 Figure 2-5 , as shown in 2-6.

[0046] At room temperature, simulations show that the specific heat capacity of QH01 is 0.88 J / (g*K) and the thermal conductivity is 200.01W / (m*K).

[0047] At 100°C, the simulation calculated that the specific heat capacity of QH01 is 0.92 J / (g*K) and the thermal conductivity is 193.65W / (m*K).

[0048] At 200°C, the simulation calculated that the specific heat capacity of QH01 is 0.96 J / (g*K) and the thermal conductivity is 183.71W / (m*K).

[0049] Based on the above simulation calculation results and analysis, the following conclusions can be drawn: from 20℃ to 550℃, the specific heat capacity gradually increases with increasing temperature, and a sudden change occurs at 560℃; while from 20℃ to 550℃, the thermal conductivity gradually decreases with increasing temperature, and a sudden change occurs at 560℃, dropping sharply, until it slowly increases with temperature after 570℃.

[0050] 4. Heat dissipation performance characterization parameters The heat transfer coefficient was previously called the total heat transfer coefficient. Current national standards and specifications uniformly refer to it as the heat transfer coefficient. The heat transfer coefficient, k, refers to the amount of heat transferred per unit area per unit time under stable heat transfer conditions, with a 1 degree (K or °C) air temperature difference on both sides of the enclosure. The unit is watts per square meter per degree (W / (m²·K)). K can be replaced by °C here. It reflects the strength of the heat transfer process.

[0051] Thermal conductivity, also known as thermal conductivity or heat transfer coefficient, is a physical quantity that measures a material's ability to conduct heat. It is defined as the amount of heat transferred through a one-square-meter area in one second under steady-state heat transfer conditions, with a one-meter-thick material and a one-degree (K or °C) temperature difference between its two surfaces. The unit is watts per meter·degree (W / (m·K)).

[0052] The thermal conductivity reflects the heat transfer properties of a material. Objects with high thermal conductivity are excellent heat conductors, while objects with low thermal conductivity are poor heat conductors or insulators. For anisotropic materials, the thermal conductivity will vary depending on the structure.

[0053] The conversion formula between heat transfer coefficient and thermal conductivity is as follows:

[0054]

[0055]

[0056] Where: — thickness of the material layer; — thermal conductivity of the material; R——thermal resistance of material layer; R0——heat transfer resistance of actual structure; Ri——internal surface heat transfer resistance; Re——external surface heat transfer resistance; K——heat transfer coefficient.

[0057] Since the heat transfer resistance of the actual structure is much greater than the heat transfer resistance of the inner and outer surfaces, the two are ignored, and the heat transfer coefficient and the heat transfer coefficient are approximately positively correlated, and the ratio is the material layer thickness:

[0058] If the material layer thickness is assumed to be 1 meter, the heat transfer coefficient and thermal conductivity coefficient are equal in value, but in different units, e.g. Figure 2-7 shown.

[0059] As can be seen from the above examples, the present invention provides an alloy material with excellent performance: QH01. In today's era of rapid technological advancement, the requirements for heat dissipation performance in various products are becoming increasingly stringent. The emergence of QH01 high-heat-transfer aluminum alloy material has brought many benefits and advantages to meeting these high-heat-transfer requirements. QH01 aluminum alloy material has excellent thermal conductivity, quickly transferring heat generated within the product. For example, electronic devices such as mobile phones and computers generate a large amount of heat during operation due to the operation of core components such as processors. Using high-heat-transfer aluminum alloy material to manufacture heat dissipation modules can quickly transfer heat away from heat sources such as chips, preventing heat accumulation from causing excessive device temperatures, effectively preventing performance degradation, system lags, and even crashes. This not only improves user experience but also extends the lifespan of the device. For automotive engines, high-heat-transfer aluminum alloy materials can be used to manufacture components such as engine blocks and radiators. The enormous heat generated by the engine during operation can be efficiently dissipated through these aluminum alloy components, maintaining the engine within an appropriate operating temperature range, ensuring stable operation, improving fuel economy, reducing energy waste, and lowering the risk of engine failure due to overheating. In industrial production, equipment with high heat dissipation requirements can significantly improve production efficiency if aluminum alloys with high heat transfer properties are used. For example, precise temperature control is crucial in precision machining equipment. The excellent heat dissipation properties of aluminum alloys enable equipment to maintain a stable temperature during long periods of continuous operation, ensuring machining accuracy, reducing scrap, and creating greater economic benefits for the enterprise.

[0060] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. An aluminum alloy, characterized in that: The chemical composition of the aluminum alloy includes Si10.5%~13.6%, Fe0.9%~1.12%, Cu≤0.12%, Mn0.21%~0.56%, Mg0.21%~0.52%, Ni≤0.15%, Zn≤0.16%, Ti≤0.15, and the balance is Al and other elements except the above elements, and the total amount of other elements is less than 0.1%.

2. The aluminum alloy according to claim 1, characterized in that The chemical composition of the aluminum alloy includes Si 10.5%~13.6%, Fe 0.9%~1.12%, Cu≤0.12%, Mn 0.21%~0.56%, Mg 0.21%~0.52%, Ni≤0.15%, Zn≤0.16%, Ti≤0.15, and the balance is Al.

3. The die-cast aluminum alloy according to claim 1 or 2, characterized in that: The mass percentage contents of Si and Cu satisfy 10.5%≤Si+Cu≤13.72%.

4. The method for preparing the aluminum alloy according to any one of claims 1 to 3, characterized in that: The following steps are involved: Aluminum alloy and / or pure metal containing Al, Si, Fe, Cu, Mn, Mg, Ni, Zn and Ti in required proportions are weighed according to the element ratio in the aluminum alloy, and the aluminum alloy is obtained by melting and die-casting.

5. The method for preparing the aluminum alloy according to any one of claims 1 to 3, characterized in that: The following steps are involved: Melting pure Al raw materials to obtain aluminum liquid; mixing aluminum liquid with raw materials containing Si, Fe, Cu, Mn and Zn to obtain a first melt; mixing the first melt, Mg and Ti to obtain a second melt; refining the second melt to obtain an aluminum alloy melt; pouring the aluminum alloy melt into an aluminum ingot mold to obtain an aluminum alloy ingot; The aluminum alloy ingot is subjected to heat shaping treatment to be made into a thin plate die casting to obtain an aluminum alloy.

6. The preparation method according to claim 5, characterized in that The melting process includes first heating the pure Al raw material to 200-230° C., preheating for 3-5 hours, then heating to 700-780° C., and keeping the temperature for 30-40 minutes.

7. The preparation method according to claim 5, characterized in that The ambient temperature for mixing the first melt, Mg and Ti is 700-760°C.

8. The preparation method according to claim 5, characterized in that Before the second melt is refined, an inert gas is introduced for degassing for 20 to 30 minutes.

9. The preparation method according to claim 5, characterized in that The temperature of the heat shaping treatment is 250-280°C.

10. The preparation method according to claim 5, characterized in that The time of the heat shaping treatment is 10 to 20 seconds.

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