High-performance aluminum alloy and preparation method

Abstract

The invention belongs to the technical field of aluminum alloy preparation, and particularly relates to a high-performance aluminum alloy and a preparation method thereof, and the high-performance aluminum alloy comprises the following components in percentage by weight: 0.8-1.1% of Si, 4.2-4.7% of Cu, 0.8-1.0% of Mn, 0.45-0.75% of Mg, 0.03-0.05% of Zr, 0.01-0.02% of Er, less than or equal to 0.2% of Fe and the balance of Al. The balance is Al; the weight ratio of Zr to Er is (2-3): 1; the tensile strength, the yield strength and the ductility are further improved, and meanwhile the three-dimensional difference is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum alloy preparation, and in particular relates to a high-performance aluminum alloy and a preparation method. Background Art

[0002] The 2A14 aluminum alloy shell used in the aerospace field requires high service performance strength, good plasticity, and instantaneous separation under certain circumstances. That is, it requires high strength and good plasticity, while the three-dimensional performance cannot be greatly different. Therefore, it is urgent to develop 2A14 aluminum alloy with higher strength and plasticity, and the 2A14 aluminum alloy shell performance is required to have a three-dimensional tensile strength of more than 430MPa, a yield strength of more than 360MPa, and an elongation of 5% to 14%. As an aluminum alloy that has been maturely used in the last century, the comprehensive performance characteristics of 2A14 aluminum alloy products are increased strength, a sharp drop in elongation, and large differences in all directions. Table 1 shows the performance standards of 2A14 aluminum alloy forgings and statistical performance data of existing products. It can be seen that its performance is still far from the new requirements. According to past production experience, it is impossible to produce products with a triaxial tensile strength of more than 430 MPa, a yield strength of more than 360 MPa, and an elongation of 5% to 14% using traditional 2A14 aluminum alloy ingots (i.e., ingots cast according to existing standards). Therefore, in order to obtain such high-quality 2A14 aluminum alloy products, we must first improve the quality of the ingots, that is, to produce high-performance 2A14 aluminum alloy ingots.

[0003] Table 1: 2A14 aluminum alloy forging performance standards and statistical existing product performance data.

[0004]

[0005] CN117904468A discloses an ultra-large size 2A14 aluminum alloy ingot and a preparation method thereof. The element composition of the 2A14 aluminum alloy is: Fe: 0.05-0.35%, Si: 0.60-0.11%, Cu: 4.0-4.6%, Mn: 0.4-0.8%, Mg: 0.5-0.8%, Ti: 0.02%-0.10%, Be: 0.0001-0.002% 0%, other elements individually ≤0.05%, total ≤0.10%; or, Fe: 0.17-0.19%, Si: 0.73-0.77%, Cu: 4.4-4.5%, Mn: 0.6-0.7%, Mg: 0.6-0.7%, Ti: 0.03%-0.06%, Be: 0.0006-0.0010%, other elements individually ≤0.05%, total ≤0.1%. It mainly refines the grains by adjusting the temperature through processes and devices. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a high-performance aluminum alloy and a preparation method, which further improves the tensile strength, yield strength and elongation, while reducing the three-dimensional difference.

[0007] The embodiment of the present invention provides a high-performance aluminum alloy, comprising the following components in percentage by weight: Si: 0.8~1.1%, Cu: 4.2~4.7%, Mn: 0.8~1.0%, Mg: 0.45~0.75%, Zr: 0.03~0.05%, Er: 0.01~0.02%, Fe: ≤0.2%; the balance is Al; The weight ratio of Zr to Er is 2 to 3:1.

[0008] Preferably, the Zr is 0.03-0.04%, and the Er is 0.015-0.02%.

[0009] Preferably, the Si content is 0.9-1.0%, the Cu content is 4.4-4.6%, and the Mn content is 0.85-0.95%.

[0010] The embodiment of the present invention provides a method for preparing the high-performance aluminum alloy, which comprises mixing raw materials of the high-performance aluminum alloy, smelting, and then casting and homogenizing to obtain the high-performance aluminum alloy.

[0011] Preferably, the smelting temperature is 700-760°C.

[0012] Preferably, the smelting includes a pre-melting stage and a refining stage, the temperature of the pre-melting stage is 700-720°C, and the temperature of the refining stage is 750-760°C.

[0013] Preferably, the casting adopts a water-cooled semi-continuous casting process with a cooling rate of 50 to 100° C. / s.

[0014] Preferably, the casting is staged casting, with an initial cooling rate of 100°C / s and a later cooling rate of 50°C / s.

[0015] Preferably, the temperature of the homogenization treatment is 480-500°C.

[0016] Preferably, the holding time of the homogenization treatment is 24 to 36 hours.

[0017] The beneficial effect of the present invention is that, by adding a small amount of Zr and Er to the aluminum alloy and controlling the content and ratio of the two, compared with simply adding Zr or Er, the tensile strength, yield strength and elongation of the aluminum alloy can be significantly improved while reducing the three-dimensional difference.

[0018] The presence of Zr forms Al3Zr nanoparticles, which serve as heterogeneous nucleation cores and refine the grains to within one level; the presence of Er generates Al3Er phase, which further inhibits grain boundary migration and improves recrystallization resistance; Zr and Er work together to form a composite precipitation phase (Al3(Zr,Er)), which significantly improves the dislocation pinning ability, thereby enhancing material strength and reducing anisotropy.

[0019] This application adds Zr elements (content 0.03% ~ 0.05%) and Er elements (content 0.01% ~ 0.02%) as the main chemical components, through the grain refinement effect of Zr elements and Er elements in aluminum alloys and the improvement of dislocation pinning in subsequent organizations, the strength and plasticity of the product are improved, and the anisotropy problem is reduced. Ultra-fine grains (average grain size ≤ 50 μm) are achieved through composite precipitation phases, which is better than the process of adding Zr alone (grain size 80 ~ 100 μm); triaxial tensile strength ≥ 440MPa, yield strength ≥ 370 MPa, elongation 6% ~ 14%; small anisotropy index, traditional 2A14 longitudinal elongation of 15%, and high elongation less than 3%; the anisotropy index of the material of the present invention is small. Process compatibility: Optimize the composition based on traditional water-cooled casting, no complex equipment modification is required, and it is suitable for industrial production.

[0020] The present invention breaks through the "inverted relationship" between strength and plasticity of traditional aluminum alloys through the synergistic effect of Er and Zr, significantly reduces the performance differences in three directions, and meets the stringent requirements of aerospace components for material homogeneity; the process is simple, the cost is controllable, and it has the potential for large-scale application.

[0021] The present invention divides the smelting process into two stages: pre-melting (700-720°C) and refining (750-760°C). The pre-melting stage ensures that low-melting-point elements (such as Mg and Si) are fully dissolved, and the refining stage promotes the uniform diffusion of high-melting-point elements such as Zr and Er, reduces the inclusion content of the melt (≤0.05%), and improves the purity of the alloy.

[0022] The present invention adopts a water-cooled semi-continuous casting process and innovatively implements a segmented cooling strategy: rapid cooling at 100°C / s in the initial stage inhibits the formation of coarse grains, and slow cooling at 50°C / s in the later stage reduces internal stress. This process improves the uniformity of the ingot structure by 30% and avoids the microscopic defects caused by the traditional single cooling rate. DETAILED DESCRIPTION Example 1

[0023] A high performance aluminum alloy comprising the following components in percentage by weight: Si: 1.0%, Cu: 4.5%, Mn: 0.9%, Mg: 0.6%, Zr: 0.04%, Er: 0.02%, Fe: 0.15%; the balance is Al; The weight ratio of Zr to Er is 2:1.

[0024] A method for preparing a high-performance aluminum alloy, comprising the following steps: 1) Raw material selection: high-purity aluminum ingots (Fe≤0.1%), Al-Zr master alloy (Zr content 10%) and Al-Er master alloy (Er content 2%), as well as Cu, Mg, Mn, Si elements or their alloys.

[0025] 2) Melting: Pre-melting: Heat the high-purity aluminum ingot to 720℃ to melt; Refining: After the high-purity aluminum ingot is melted, it is heated to 760°C, and Al-Zr and Al-Er master alloys, as well as alloys of Cu, Mg, Mn, and Si elements are added in sequence, and stirred until completely dissolved; after refining and degassing, it is allowed to stand for 30 minutes.

[0026] 3) Casting: A water-cooled semi-continuous casting process is used, with an initial cooling rate of 100°C / s, cooling for 4s, cooling to about 360°C, and then controlling the cooling rate to 50°C / s, cooling for 6-7s, cooling to room temperature to obtain an ingot.

[0027] 4) Homogenization treatment: The ingot is kept at 490°C for 30 hours to eliminate segregation and obtain a high-performance aluminum alloy. Example 2

[0028] Compared with Example 1, Example 2 differs in that Zr is 0.03%, Er is 0.015%, and the rest is the same as Example 1. Comparative Example 1

[0029] Compared with Example 1, Comparative Example 1 differs in that Zr is 0.04%, Er is 0.01%, and the rest is the same as Example 1. Comparative Example 2

[0030] Compared with Example 1, Comparative Example 2 differs in that Zr is 0.03%, Er is 0.02%, and the rest is the same as Example 1. Comparative Example 3

[0031] Compared with Example 1, Comparative Example 3 has the following differences: Zr is 0.06%, Er is 0%, and the rest is the same as Example 1. Comparative Example 4

[0032] The difference between Comparative Example 4 and Example 1 is that during casting, the cooling rate is 100°C / s, and it takes 7-8s to cool to room temperature. Other aspects are the same as Example 1.

[0033] The ingots produced by the above scheme were compared with the aluminum alloy forging rings produced by the same forging process, and the performance of each embodiment and comparative example was measured to obtain the aluminum alloy forging ring performance test results shown in Table 2.

[0034] Table 2 Performance test results of aluminum alloy forging rings

[0035] The calculation method of the difference of the three-way elongation of the present invention is: longitudinal elongation-high-speed elongation.

[0036] A person skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of protection of the present application is limited to these examples. In line with the concept of the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of different aspects of one or more embodiments of the present application as described above, which are not provided in detail for the sake of simplicity.

[0037] One or more embodiments of the present application are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the present application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of one or more embodiments of the present application should be included in the protection scope of the present application.

Claims

1. A high performance aluminum alloy, characterized in that: The composition includes the following weight percentages: Si: 0.8~1.1%, Cu: 4.2~4.7%, Mn: 0.8~1.0%, Mg: 0.45~0.75%, Zr：0.03～0.05%， Er：0.01～0.02%， Fe: ≤0.2%; the balance is Al; The weight ratio of Zr to Er is 2 to 3:

1.

2. The high performance aluminum alloy according to claim 1, characterized in that: The Zr is 0.03-0.04%, and the Er is 0.015-0.02%.

3. The high performance aluminum alloy according to claim 1, characterized in that: The Si content is 0.9-1.0%, the Cu content is 4.4-4.6%, and the Mn content is 0.85-0.95%.

4. A method for preparing a high-performance aluminum alloy according to any one of claims 1 to 3, characterized in that: The raw materials of the high-performance aluminum alloy are mixed, smelted, and then cast and homogenized to obtain the high-performance aluminum alloy.

5. The preparation method according to claim 4, characterized in that: The smelting temperature is 700-760°C.

6. The preparation method according to claim 5, characterized in that: The smelting includes a pre-melting stage and a refining stage. The temperature of the pre-melting stage is 700-720°C, and the temperature of the refining stage is 750-760°C.

7. The preparation method according to claim 4, characterized in that: The casting adopts a water-cooled semi-continuous casting process with a cooling rate of 50-100°C / s.

8. The preparation method according to claim 7, characterized in that: The casting is staged casting, with an initial cooling rate of 100°C / s and a later cooling rate of 50°C / s.

9. The preparation method according to claim 4, characterized in that: The temperature of the homogenization treatment is 480-500°C.

10. The preparation method according to claim 9, characterized in that: The heat preservation time of the homogenization treatment is 24 to 36 hours.

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