A modified ZL303 aluminum alloy and its manufacturing method

Abstract

This invention belongs to the field of aluminum alloy technology, specifically a modified ZL303 aluminum alloy and its manufacturing method. The ZL303 aluminum alloy is modified using a Zr-based amorphous nanocrystalline alloy modifier. By modifying the ZL303 aluminum alloy, its hardness and toughness are improved while maintaining its good corrosion resistance and casting performance. The modified ZL303 aluminum alloy obtained by this invention has an average grain size of 8.0–8.5 μm, a Vickers hardness ≥75 HV, a tensile strength ≥220 MPa, and a fracture toughness ≥70 kg·mm². ‑3 / 2 .

Description

Technical Field

[0001] This invention relates to the field of surface modification technology for metallic materials, specifically to a modified ZL303 aluminum alloy and its manufacturing method. Background Technology

[0002] Aluminum alloys are alloys based on aluminum with the addition of certain amounts of other alloying elements, and are one of the lightweight metal materials. In addition to the general properties of aluminum, aluminum alloys also possess specific alloy characteristics due to the different types and amounts of alloying elements added. Aluminum alloys have high tensile strength, a specific strength approaching that of high-alloy steel, a specific stiffness exceeding that of steel, good casting and plastic processing properties, good electrical and thermal conductivity, good corrosion resistance and weldability, and can be used as structural materials. They have wide applications in aerospace, aviation, transportation, construction, electromechanical, light chemical, and daily consumer goods.

[0003] ZL303 aluminum alloy has high corrosion resistance, similar to ZL301 aluminum alloy. Its casting performance, tendency to form shrinkage cavities due to gas absorption, and tendency to hot cracking are all better than ZL301 aluminum alloy. However, it has a large shrinkage rate and only moderate airtightness. ZL303 aluminum alloy castings cannot be heat-treated for strengthening, but its high-temperature performance is better than ZL301 aluminum alloy. It also has better machinability and significantly improved weldability than ZL301 aluminum alloy, and its production process is simpler. However, ZL303 aluminum alloy has poor hardness and toughness, making it suitable only for manufacturing parts for ships, aircraft, and internal combustion engines that bear moderate loads. Summary of the Invention

[0004] To address the problems existing in the prior art, the main objective of this invention is to propose a modified ZL303 aluminum alloy and its manufacturing method. By modifying the ZL303 aluminum alloy, its hardness and toughness are further improved while maintaining its good corrosion resistance and casting performance.

[0005] To address the aforementioned technical problems, according to one aspect of the present invention, the present invention provides the following technical solution:

[0006] A method for manufacturing a modified ZL303 aluminum alloy includes the following steps:

[0007] S1. Place the ZL303 aluminum alloy ingot in a sealed ceramic crucible, heat it to 700-730℃ and hold it for 15-30 minutes to completely melt the ZL303 aluminum alloy ingot and form a molten aluminum alloy liquid.

[0008] S2. Add Zr-based amorphous nanocrystalline alloy regulator to the aluminum alloy melt, keep it at 600-650℃ for 3-5 minutes, and then stir and disperse it. During the stirring and dispersion process, cool down to 580-590℃ and then keep it at 15-25 minutes to obtain ZL303 aluminum alloy melt containing Zr-based amorphous nanocrystalline material.

[0009] S3. The ZL303 aluminum alloy melt containing Zr-based amorphous nanocrystals is poured into a steel mold and naturally cooled to obtain the modified ZL303 aluminum alloy.

[0010] As a preferred embodiment of the manufacturing method of modified ZL303 aluminum alloy according to the present invention, in step S1, after forming the aluminum alloy molten liquid, hexachloroethane is wrapped in aluminum foil and immersed in the aluminum alloy molten liquid in a sealed ceramic crucible using the bell jar method. It is then refined at 700-730°C for 8-15 minutes, and then the slag is removed. After the slag is removed, the temperature is lowered to 600-650°C.

[0011] In a preferred embodiment of the manufacturing method of the modified ZL303 aluminum alloy described in this invention, in step S1, the amount of hexachloroethane added is 0.2 to 0.4% of the mass of the ZL303 aluminum alloy ingot.

[0012] In a preferred embodiment of the manufacturing method of the modified ZL303 aluminum alloy described in this invention, in step S2, the amount of Zr-based amorphous nanocrystals added is 0.1 to 0.2% of the mass of the ZL303 aluminum alloy ingot.

[0013] In a preferred embodiment of the manufacturing method of modified ZL303 aluminum alloy according to the present invention, in step S2, the stirring rate is 150-200 rpm and the stirring time is 3-8 min.

[0014] In a preferred embodiment of the manufacturing method of modified ZL303 aluminum alloy according to the present invention, in step S2, the Zr-based amorphous nanocrystalline alloy regulator is prepared by: thoroughly mixing ZrTiCuNi amorphous alloy powder with a particle size of 10-30 μm and Al powder with a particle size of 45-50 μm in a ball mill at a mass ratio of (2-4):(6-8), and then pressing the mixture into a cylindrical casting. This casting is the Zr-based amorphous nanocrystalline alloy regulator. The Zr-based amorphous nanocrystalline alloy regulator is stored in a vacuum environment.

[0015] As a preferred embodiment of the manufacturing method of modified ZL303 aluminum alloy according to the present invention, in step S2, Zr-based amorphous nanocrystalline alloy regulator wrapped in aluminum foil is added to the molten aluminum alloy in the sealed ceramic crucible after slag removal using the bell jar method.

[0016] In a preferred embodiment of the manufacturing method of the modified ZL303 aluminum alloy described in this invention, the temperature of the steel mold in step S3 is 100-150°C.

[0017] To solve the above-mentioned technical problems, according to another aspect of the present invention, the present invention provides the following technical solution:

[0018] A modified ZL303 aluminum alloy, manufactured using the aforementioned method for producing modified ZL303 aluminum alloy, exhibits a Vickers hardness ≥75HV, tensile strength ≥220MPa, and fracture toughness ≥70kg·mm². -3 / 2 .

[0019] As a preferred embodiment of the modified ZL303 aluminum alloy described in this invention, the average grain size of the modified ZL303 aluminum alloy is 8.0 to 8.5 μm.

[0020] The beneficial effects of this invention are as follows:

[0021] This invention proposes a modified ZL303 aluminum alloy and its manufacturing method. The ZL303 aluminum alloy is modified using a Zr-based amorphous nanocrystalline alloy modifier. This modification improves the hardness and toughness of the ZL303 aluminum alloy while maintaining its good corrosion resistance and casting properties. The modified ZL303 aluminum alloy obtained by this invention has an average grain size of 8.0–8.5 μm, a Vickers hardness ≥75 HV, a tensile strength ≥220 MPa, and a fracture toughness ≥70 kg·mm². -3 / 2 . Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0023] Figure 1 This is an electron microscope image of the modified ZL303 aluminum alloy in Example 1 of the present invention.

[0024] Figure 2 This is an electron microscope image of the ZL303 aluminum alloy before modification in Example 1 of the present invention.

[0025] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0026] The technical solutions described below in conjunction with the embodiments will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] This invention proposes a modified ZL303 aluminum alloy and its manufacturing method. By modifying the ZL303 aluminum alloy, its hardness and toughness are further improved while maintaining its good corrosion resistance and casting performance.

[0028] According to one aspect of the present invention, the present invention provides the following technical solution:

[0029] A method for manufacturing a modified ZL303 aluminum alloy includes the following steps:

[0030] S1. Place the ZL303 aluminum alloy ingot in a sealed ceramic crucible, heat it to 700-730℃ and hold it for 15-30 minutes to completely melt the ZL303 aluminum alloy ingot and form a molten aluminum alloy liquid.

[0031] S2. Add Zr-based amorphous nanocrystalline alloy regulator to the aluminum alloy melt, and after standing at 600-650℃ for 3-5 minutes, use a stirrer to stir and disperse. During the stirring and dispersion process, lower the temperature to 580-590℃, and then keep it at that temperature for 15-25 minutes to obtain ZL303 aluminum alloy melt containing Zr-based amorphous nanocrystalline material.

[0032] S3. The ZL303 aluminum alloy melt containing Zr-based amorphous nanocrystals is poured into a steel mold and naturally cooled to obtain the modified ZL303 aluminum alloy.

[0033] Preferably, in step S1, the ceramic crucible is a preheated ceramic crucible; after the aluminum alloy molten liquid is formed, hexachloroethane is wrapped in aluminum foil and immersed in the aluminum alloy molten liquid in the sealed ceramic crucible using the bell jar method, and refined at 700-730℃ for 8-15 minutes, then the slag is removed, and after the slag is removed, the temperature is lowered to 600-650℃; the hexachloroethane is preheated and dried hexachloroethane, which adsorbs hydrogen and oxide inclusions in the aluminum alloy molten liquid and floats to the surface in the form of bubbles to form slag.

[0034] Preferably, in step S1, the amount of hexachloroethane added is 0.2% to 0.4% of the mass of the ZL303 aluminum alloy ingot. Specifically, the amount of hexachloroethane added can be any one or a range between any two of, for example, 0.2%, 0.25%, 0.3%, 0.35%, and 0.4% of the mass of the ZL303 aluminum alloy ingot.

[0035] Preferably, in step S2, the amount of Zr-based amorphous nanocrystals added is 0.1% to 0.2% of the mass of the ZL303 aluminum alloy ingot. Specifically, the amount of Zr-based amorphous nanocrystals added can be any one or a range between any two of, for example, 0.1%, 0.12%, 0.15%, 0.18%, and 0.2% of the mass of the ZL303 aluminum alloy ingot.

[0036] Preferably, in step S2, the stirring rate is 150–200 rpm, and the stirring time is 3–8 min. Specifically, the stirring rate can be any one or a range between any two of, for example, 150 rpm, 160 rpm, 170 rpm, 180 rpm, 190 rpm, and 200 rpm; the stirring time can be any one or a range between any two of, for example, 3 min, 4 min, 5 min, 6 min, 7 min, and 8 min.

[0037] Preferably, in step S2, the Zr-based amorphous nanocrystalline alloy regulator is prepared by mixing ZrTiCuNi amorphous alloy powder with a particle size of 10-30 μm and Al powder with a particle size of 45-50 μm in a ball mill at a mass ratio of (2-4):(6-8), and then pressing the mixture into a cylindrical blank with a diameter of 30 mm. This blank is the Zr-based amorphous nanocrystalline alloy regulator. The Zr-based amorphous nanocrystalline alloy regulator is stored in a vacuum environment. More preferably, in step S2, ZrTiCuNi amorphous alloy strips are ball-milled in a mechanical ball mill to obtain amorphous alloy powder. The composition of the ZrTiCuNi amorphous alloy strips / powder, by weight percentage, includes: Ti 11wt%, Cu 13wt%, Ni 9wt%, Be 3wt%, with the balance being Zr. Specifically, ZrTiCuNi amorphous alloy strips are ball-milled at 200 rpm for 2 hours in a mechanical ball mill to obtain amorphous alloy powder. Preferably, in step S2, Zr-based amorphous nanocrystalline alloy modifier wrapped in aluminum foil is added to the molten aluminum alloy in a sealed ceramic crucible after slag removal using a bell jar method. This invention achieves heterogeneous nucleation and grain refinement by adding Zr-based amorphous nanocrystalline alloy modifier, while simultaneously refining the second phase to modify ZL303 aluminum alloy.

[0038] Preferably, in step S3, the temperature of the steel mold is 100-150°C.

[0039] According to another aspect of the present invention, the present invention provides the following technical solution:

[0040] A modified ZL303 aluminum alloy, manufactured using the aforementioned method for producing modified ZL303 aluminum alloy, exhibits a Vickers hardness ≥75HV, tensile strength ≥220MPa, and fracture toughness ≥70kg·mm². -3 / 2 .

[0041] Preferably, the modified ZL303 aluminum alloy has an average grain size of 8.0 to 8.5 μm.

[0042] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0043] The preparation method of the Zr-based amorphous nanocrystalline alloy regulator in each embodiment is as follows: ZrTiCuNi amorphous alloy strips are ball-milled in a mechanical ball mill to obtain amorphous alloy powder. The composition of the ZrTiCuNi amorphous alloy strip / powder, by weight percentage, includes: Ti 11wt%, Cu 13wt%, Ni 9wt%, Be 3wt%, with the balance being Zr. Specifically, the ZrTiCuNi amorphous alloy strips are ball-milled in a mechanical ball mill at 200 rpm for 2 hours to obtain ZrTiCuNi amorphous alloy powder with a particle size of 10-30 μm. The ZrTiCuNi amorphous alloy powder with a particle size of 10-30 μm is then thoroughly mixed with Al powder with a particle size of 45-50 μm in a ball mill at a mass ratio of 3:7, and pressed into a cylindrical casting with a diameter of 30 mm. This casting is the Zr-based amorphous nanocrystalline alloy regulator. The Zr-based amorphous nanocrystalline alloy regulator is stored under vacuum.

[0044] Example 1

[0045] A method for manufacturing a modified ZL303 aluminum alloy includes the following steps:

[0046] S1. Cast ZL303 aluminum alloy ingots (its electron microscope image is shown below) Figure 2 As shown, the ZL303 aluminum alloy ingot has a Vickers hardness of 50 HV, a tensile strength of 143 MPa, and a fracture toughness of 66 kg·mm². -3 / 2 The ZL303 aluminum alloy ingot is placed in a sealed, preheated ceramic crucible and heated to 710°C for 20 minutes to completely melt the ingot and form a molten aluminum alloy. 0.3% of the mass of the ZL303 aluminum alloy ingot is wrapped in aluminum foil and immersed in the molten aluminum alloy in the sealed ceramic crucible using the bell jar method. The mixture is then refined at 710°C for 10 minutes, followed by slag removal. After slag removal, the temperature is lowered to 650°C.

[0047] S2. In the aluminum alloy molten liquid in the sealed ceramic crucible after slag removal, Zr-based amorphous nanocrystalline alloy regulator wrapped in aluminum foil was added using the bell jar method. The amount of Zr-based amorphous nanocrystalline added was 0.15% of the mass of ZL303 aluminum alloy ingot. After standing at 650℃ for 3 minutes, it was stirred and dispersed using a stirrer at a stirring speed of 150 rpm for 5 minutes. During the stirring and dispersion process, the temperature was lowered to 590℃ and then held for 20 minutes to obtain ZL303 aluminum alloy melt containing Zr-based amorphous nanocrystalline.

[0048] S3. The ZL303 aluminum alloy melt containing Zr-based amorphous nanocrystals was poured into a steel mold at 100℃ and allowed to cool naturally to obtain the modified ZL303 aluminum alloy. The electron microscope image of the modified ZL303 aluminum alloy is shown below. Figure 1As shown, its average grain size is 8.31 μm, the reinforcing phase is refined and uniformly distributed, the Vickers hardness is 75 HV, the tensile strength reaches 225 MPa, and the fracture toughness is 71 kg·mm. -3 / 2 The microstructure is significantly optimized and the mechanical properties are significantly improved.

[0049] Example 2

[0050] A method for manufacturing a modified ZL303 aluminum alloy includes the following steps:

[0051] S1. Cast ZL303 aluminum alloy ingots (its electron microscope image is shown below) Figure 2 As shown, the ZL303 aluminum alloy ingot has a Vickers hardness of 50 HV, a tensile strength of 143 MPa, and a fracture toughness of 66 kg·mm². -3 / 2 The ZL303 aluminum alloy ingot is placed in a sealed, preheated ceramic crucible and heated to 700°C for 20 minutes to completely melt the ingot and form a molten aluminum alloy. 0.3% of the mass of the ZL303 aluminum alloy ingot is wrapped in aluminum foil and immersed in the molten aluminum alloy in the sealed ceramic crucible using the bell jar method. The mixture is then refined at 700°C for 10 minutes, followed by slag removal. After slag removal, the temperature is lowered to 650°C.

[0052] S2. In the aluminum alloy molten liquid in the sealed ceramic crucible after slag removal, Zr-based amorphous nanocrystalline alloy regulator wrapped in aluminum foil was added using the bell jar method. The amount of Zr-based amorphous nanocrystalline added was 0.12% of the mass of ZL303 aluminum alloy ingot. After standing at 620℃ for 5 min, it was stirred and dispersed using a stirrer at a stirring speed of 200 rpm for 5 min. During the stirring and dispersion process, the temperature was lowered to 580℃ and then held for 20 min to obtain ZL303 aluminum alloy melt containing Zr-based amorphous nanocrystalline.

[0053] S3. The ZL303 aluminum alloy melt containing Zr-based amorphous nanocrystals was poured into a steel mold at 100℃ and allowed to cool naturally to obtain a modified ZL303 aluminum alloy. The modified ZL303 aluminum alloy has an average grain size of 8.35μm, refined and uniformly distributed reinforcing phases, a Vickers hardness of 79HV, a tensile strength of 221MPa, and a fracture toughness of 79kg·mm. -3 / 2 The microstructure is significantly optimized and the mechanical properties are significantly improved.

[0054] Example 3

[0055] A method for manufacturing a modified ZL303 aluminum alloy includes the following steps:

[0056] S1. Cast ZL303 aluminum alloy ingots (its electron microscope image is shown below) Figure 2As shown, the ZL303 aluminum alloy ingot has a Vickers hardness of 50 HV, a tensile strength of 143 MPa, and a fracture toughness of 66 kg·mm². -3 / 2 The ZL303 aluminum alloy ingot is placed in a sealed, preheated ceramic crucible and heated to 715°C for 10 minutes to completely melt the ingot and form a molten aluminum alloy. 0.3% of the mass of the ZL303 aluminum alloy ingot is wrapped in aluminum foil and immersed in the molten aluminum alloy in the sealed ceramic crucible using the bell jar method. The mixture is then refined at 715°C for 10 minutes, followed by slag removal. After slag removal, the temperature is lowered to 640°C.

[0057] S2. In the aluminum alloy molten liquid in the sealed ceramic crucible after slag removal, Zr-based amorphous nanocrystalline alloy regulator wrapped in aluminum foil was added using the bell jar method. The amount of Zr-based amorphous nanocrystalline added was 0.18% of the mass of ZL303 aluminum alloy ingot. After standing at 630℃ for 5 minutes, it was stirred and dispersed using a stirrer at a stirring speed of 180 rpm for 5 minutes. During the stirring and dispersion process, the temperature was lowered to 580℃ and then held for 20 minutes to obtain ZL303 aluminum alloy melt containing Zr-based amorphous nanocrystalline.

[0058] S3. The ZL303 aluminum alloy melt containing Zr-based amorphous nanocrystals was poured into a steel mold at 100℃ and allowed to cool naturally to obtain a modified ZL303 aluminum alloy. The modified ZL303 aluminum alloy has an average grain size of 8.28 μm, refined and uniformly distributed reinforcing phases, a Vickers hardness of 77 HV, a tensile strength of 236 MPa, and a fracture toughness of 71 kg·mm². -3 / 2 The microstructure is significantly optimized and the mechanical properties are significantly improved.

[0059] Comparative Example 1

[0060] The difference from Example 1 is that the amount of Zr-based amorphous nanocrystals added is 0.05% of the mass of the ZL303 aluminum alloy ingot;

[0061] The modified ZL303 aluminum alloy prepared in this comparative example has an average grain size of 17.58 μm, a Vickers hardness of 67 HV, a tensile strength of 140 MPa, and a fracture toughness of 69 kg·mm². -3 / 2 .

[0062] Comparative Example 2

[0063] The difference from Example 1 is that the amount of Zr-based amorphous nanocrystals added is 0.3% of the mass of the ZL303 aluminum alloy ingot;

[0064] The modified ZL303 aluminum alloy prepared in this comparative example has an average grain size of 25.17 μm, a Vickers hardness of 52 HV, a tensile strength of 132 MPa, and a fracture toughness of 67 kg·mm².-3 / 2 .

[0065] Comparative Example 3

[0066] The difference from Example 1 lies in the preparation method of the Zr-based amorphous nanocrystalline alloy regulator: ZrTiCuNi amorphous alloy strips are ball-milled in a mechanical ball mill to obtain amorphous alloy powder. The composition of the ZrTiCuNi amorphous alloy strip / powder, by weight percentage, includes: Ti 11wt%, Cu 13wt%, Ni 9wt%, Be 3wt%, with the balance being Zr. Specifically, the ZrTiCuNi amorphous alloy strips are ball-milled in a mechanical ball mill at 200 rpm for 2 hours to obtain ZrTiCuNi amorphous alloy powder with a particle size of 10–30 μm. The ZrTiCuNi amorphous alloy powder with a particle size of 10–30 μm is then thoroughly mixed with Al powder with a particle size of 45–50 μm in a ball mill at a mass ratio of 1:1, and pressed into a cylindrical casting with a diameter of 30 mm. This casting is the Zr-based amorphous nanocrystalline alloy regulator. Zr-based amorphous nanocrystalline alloy modifiers are stored in a vacuum environment.

[0067] The modified ZL303 aluminum alloy prepared in this comparative example has an average grain size of 29.28 μm, a Vickers hardness of 62 HV, a tensile strength of 137 MPa, and a fracture toughness of 68 kg·mm². -3 / 2 .

[0068] Comparative Example 4

[0069] The difference from Example 1 is that the temperature was lowered to 580°C during the stirring and dispersion process, and then held for 45 minutes to obtain a ZL303 aluminum alloy melt containing Zr-based amorphous nanocrystals.

[0070] The modified ZL303 aluminum alloy prepared in this comparative example has an average grain size of 35.31 μm, a Vickers hardness of 48 HV, a tensile strength of 116 MPa, and a fracture toughness of 62 kg·mm². -3 / 2 .

[0071] As can be seen from the above embodiments and comparative examples, the present invention uses a Zr-based amorphous nanocrystalline alloy modifier to modify ZL303 aluminum alloy, achieving heterogeneous nucleation to refine the grains and simultaneously refine the second phase. By modifying the ZL303 aluminum alloy, its hardness and toughness are improved while maintaining its good corrosion resistance and casting performance. The modified ZL303 aluminum alloy produced by the present invention has an average grain size of 8.0–8.5 μm, a Vickers hardness ≥75 HV, a tensile strength ≥220 MPa, and a fracture toughness ≥70 kg·mm². -3 / 2 .

[0072] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for manufacturing a modified ZL303 aluminum alloy, characterized in that, Includes the following steps: S1. Place the ZL303 aluminum alloy ingot in a sealed ceramic crucible, heat it to 700~730℃ and hold it for 15~30 minutes to completely melt the ZL303 aluminum alloy ingot and form a molten aluminum alloy liquid. S2. Add a Zr-based amorphous nanocrystalline alloy modifier to the molten aluminum alloy. Hold the mixture at 600-650℃ for 3-5 minutes, then stir and disperse. During the stirring and dispersion process, lower the temperature to 580-590℃ and hold for 15-25 minutes to obtain a ZL303 aluminum alloy melt containing Zr-based amorphous nanocrystalline materials. The amount of Zr-based amorphous nanocrystalline alloy modifier added is 0.1-0.2% of the mass of the ZL303 aluminum alloy ingot. The preparation method of the gold regulator is as follows: ZrTiCuNi amorphous alloy powder with a particle size of 10~30μm and Al powder with a particle size of 45~50μm are thoroughly mixed in a ball mill at a mass ratio of (2~4):(6~8), and then pressed into a cylindrical casting. This casting is the Zr-based amorphous nanocrystalline alloy regulator. The Zr-based amorphous nanocrystalline alloy regulator is stored in a vacuum environment. The composition of ZrTiCuNi amorphous alloy powder, by weight percentage, includes: Ti 11wt%, Cu 13wt%, Ni 9wt%, Be 3wt%, with the balance being Zr. S3. The ZL303 aluminum alloy melt containing Zr-based amorphous nanocrystals is poured into a steel mold and naturally cooled to obtain the modified ZL303 aluminum alloy.

2. The method for manufacturing the modified ZL303 aluminum alloy according to claim 1, characterized in that, In step S1, after the aluminum alloy melt is formed, hexachloroethane is wrapped in aluminum foil and immersed in the aluminum alloy melt in a sealed ceramic crucible using the bell jar method. It is then refined at 700~730℃ for 8~15 minutes, and then the slag is removed. After the slag is removed, the temperature is lowered to 600~650℃.

3. The method for manufacturing the modified ZL303 aluminum alloy according to claim 2, characterized in that, In step S1, the amount of hexachloroethane added is 0.2 to 0.4% of the mass of the ZL303 aluminum alloy ingot.

4. The method for manufacturing the modified ZL303 aluminum alloy according to claim 1, characterized in that, In step S2, the stirring rate is 150~200 rpm and the stirring time is 3~8 min.

5. The method for manufacturing the modified ZL303 aluminum alloy according to claim 1, characterized in that, In step S2, a Zr-based amorphous nanocrystalline alloy regulator wrapped in aluminum foil is added to the molten aluminum alloy in a sealed ceramic crucible after slag removal using the bell jar method.

6. The method for manufacturing the modified ZL303 aluminum alloy according to claim 1, characterized in that, In step S3, the temperature of the steel mold is 100~150℃.

7. A modified ZL303 aluminum alloy, characterized in that, The modified ZL303 aluminum alloy is manufactured using the manufacturing method described in any one of claims 1-6. The modified ZL303 aluminum alloy has a Vickers hardness ≥75HV, tensile strength ≥220MPa, and fracture toughness ≥70kg·mm². -3 / 2 .

8. The modified ZL303 aluminum alloy according to claim 7, characterized in that, The average grain size of the modified ZL303 aluminum alloy is 8.0~8.5μm.

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