A high-performance aluminum alloy and preparation method

Abstract

The present invention belongs to the technical field of aluminum alloy preparation, and particularly relates to a high-performance aluminum alloy and a preparation method, which include components with 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 - 3:1; the present invention further improves the tensile strength, yield strength and elongation, and at the same time reduces the triaxial difference.

Description

Technical Field

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

[0002] For the 2A14 aluminum alloy shell used in the aerospace field, it is required to have high service performance strength, good plasticity, and instantaneous separation under specific circumstances, that is, while requiring high strength and good plasticity, the three-directional properties should not have large differences. Therefore, it is urgent to develop a 2A14 aluminum alloy with higher strength and plasticity, and it is required that the three-directional tensile strength of the 2A14 aluminum alloy shell is above 430 MPa, the yield strength is above 360 MPa, and the elongation is 5% - 14%. As an aluminum alloy that has been maturely used since the last century, the comprehensive performance characteristics of 2A14 aluminum alloy are that the strength increases while the elongation drops sharply, and the differences in each direction are large. Table 1 shows the performance standards of 2A14 aluminum alloy forgings and the performance data of existing products. It can be seen that there is still a large gap between its performance and the new requirements. According to past production experience, it is impossible to prepare products with a three-directional tensile strength above 430 MPa, a yield strength above 360 MPa, and an elongation of 5% - 14% using traditional 2A14 aluminum alloy ingots (i.e., ingots according to existing standards). Therefore, to obtain 2A14 aluminum alloy products with such high requirements, it is necessary to start with improving the quality of the ingots, that is, to prepare high-performance 2A14 aluminum alloy ingots.

[0003] Table 1: Performance standards of 2A14 aluminum alloy forgings and performance data of existing products.

[0004]

[0005] CN117904468A discloses an extra-large specification 2A14 aluminum alloy ingot blank 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 - 0.0020%, and for other elements, each is ≤0.05% and the total is ≤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%, and for other elements, each is ≤0.05% and the total is ≤0.1%. It mainly adjusts the temperature through processes and devices to refine the grains. 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, further improving the tensile strength, yield strength and elongation, while reducing the triaxial difference.

[0007] An embodiment of the present invention provides a high-performance aluminum alloy, including the following components in weight percentage:

[0008] Si: 0.8 - 1.1%,

[0009] Cu: 4.2 - 4.7%,

[0010] Mn: 0.8 - 1.0%,

[0011] Mg: 0.45 - 0.75%,

[0012] Zr: 0.03 - 0.05%,

[0013] Er: 0.01 - 0.02%,

[0014] Fe: ≤0.2%; the balance is Al;

[0015] The weight ratio of Zr to Er is 2 - 3:1.

[0016] Preferably, the Zr is 0.03 - 0.04% and the Er is 0.015 - 0.02%.

[0017] Preferably, the Si is 0.9 - 1.0%, the Cu is 4.4 - 4.6%, and the Mn is 0.85 - 0.95%.

[0018] An embodiment of the present invention provides a preparation method of the high-performance aluminum alloy. Mix the raw materials of the high-performance aluminum alloy, carry out melting, and then carry out casting and homogenization treatment to obtain the high-performance aluminum alloy.

[0019] Preferably, the temperature of the melting is 700 - 760 °C.

[0020] Preferably, the melting 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.

[0021] Preferably, the casting adopts a water-cooled semi-continuous casting process, and the cooling rate is 50 - 100 °C / s.

[0022] Preferably, the casting is segmented casting, the initial cooling rate is 100 °C / s, and the later cooling rate is 50 °C / s.

[0023] Preferably, the temperature of the homogenization treatment is 480 - 500 °C.

[0024] Preferably, the heat preservation time for the homogenization treatment is 24 to 36 h.

[0025] The beneficial effects of the present invention are as follows: A small amount of Zr and Er are added to the aluminum alloy, and the contents and ratios of the two are controlled. Compared with the simple addition of Zr or Er alone, the tensile strength, yield strength, and elongation of the aluminum alloy can be significantly improved simultaneously, while reducing the triaxial difference.

[0026] The presence of Zr forms Al3Zr nanoparticles, which serve as heterogeneous nucleation cores, refining the grains to within grade one; the presence of Er generates the Al3Er phase, further inhibiting grain boundary migration and enhancing the recrystallization resistance; the combined action of Zr and Er forms a composite precipitation phase (Al3(Zr,Er)), significantly improving the dislocation pinning ability, thereby enhancing the material strength and reducing anisotropy.

[0027] In this application, Zr element (content 0.03% - 0.05%) and Er element (content 0.01% - 0.02%) are added as the main chemical components. Through the grain refinement effect of Zr element and Er element in the aluminum alloy and the improvement of dislocation pinning in the subsequent structure, the strength and plasticity of the product are improved, while reducing the anisotropy problem. Ultra-fine grain refinement (average grain size ≤ 50 μm) is achieved through the composite precipitation phase, which is superior to the process of adding Zr alone (grain size 80 - 100 μm); the triaxial tensile strength ≥ 440 MPa, the yield strength ≥ 370 MPa, and the elongation is 6% - 14%; the anisotropy index is small. For the traditional 2A14, the longitudinal elongation rate reaches 15%, while the high-direction elongation rate is less than 3%; the anisotropy index of the material of the present invention is small. Process compatibility: Based on the traditional water-cooled casting, the composition is optimized, and no complex equipment modification is required, which is suitable for industrial production.

[0028] Through the synergistic effect of Er and Zr, the present invention breaks through the "inverted relationship" between the strength and plasticity of traditional aluminum alloys; significantly reduces the triaxial property difference, meeting the stringent requirements of aerospace components for material homogeneity; the process is simple and the cost is controllable, with great potential for large-scale application.

[0029] The melting process of the present invention is divided into two stages: pre-melting (700 - 720 °C) and refining (750 - 760 °C). The pre-melting stage ensures the full dissolution of low-melting-point elements (such as Mg, Si), and the refining stage promotes the uniform diffusion of high-melting-point elements such as Zr and Er, reducing the melt inclusion content (≤ 0.05%) and improving the alloy purity.

[0030] The present invention adopts a water-cooled semi-continuous casting process and innovatively implements a segmented cooling strategy: in the initial stage, rapid cooling at 100 °C / s is used to inhibit the formation of coarse grains, and in the later stage, slow cooling at 50 °C / s is used to reduce internal stress. This process improves the tissue uniformity of the ingot by 30% and avoids micro-defects caused by the traditional single cooling rate. Detailed implementation mode Example 1

[0031] A high-performance aluminum alloy comprises the following components in weight percentage:

[0032] Si: 1.0%,

[0033] Cu: 4.5%,

[0034] Mn: 0.9%,

[0035] Mg: 0.6%,

[0036] Zr: 0.04%,

[0037] Er: 0.02%,

[0038] Fe: 0.15%; the balance is Al;

[0039] The weight ratio of Zr to Er is 2:1.

[0040] A preparation method of a high-performance aluminum alloy comprises the following steps:

[0041] 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%) are adopted, as well as Cu, Mg, Mn, Si elements or their alloys.

[0042] 2) Melting:

[0043] Pre-melting: The high-purity aluminum ingots are heated to 720°C for melting;

[0044] Refining: After the high-purity aluminum ingots are melted, they are heated to 760°C, and the Al-Zr and Al-Er master alloys, as well as the alloys of Cu, Mg, Mn, Si elements, are added in sequence, and stirred until completely dissolved; after refining and degassing, it is left standing for 30 minutes.

[0045] 3) Casting: The water-cooled semi-continuous casting process is adopted. The initial cooling rate is 100°C / s, cooled for 4s, cooled to about 360°C, and then the cooling rate is controlled at 50°C / s, cooled for 6-7s, and cooled to room temperature to obtain ingots.

[0046] 4) Homogenization treatment: The ingots are kept at 490°C for 30 hours to eliminate segregation, and a high-performance aluminum alloy is obtained. Example 2

[0047] Compared with Example 1, Example 2 is different in that: Zr is 0.03% and Er is 0.015%, and the rest is the same as Example 1. Comparative example 1

[0048] Comparative Example 1 is different from Example 1 in that: Zr is 0.04% and Er is 0.01%, and the rest is the same as in Example 1. Comparative Example 2

[0049] Comparative Example 2 is different from Example 1 in that: Zr is 0.03% and Er is 0.02%, and the rest is the same as in Example 1. Comparative Example 3

[0050] Comparative Example 3 is different from Example 1 in that: Zr is 0.06% and Er is 0%, and the rest is the same as in Example 1. Comparative Example 4

[0051] Comparative Example 4 is different from Example 1 in that: during casting, the cooling rate is 100 °C / s and it is cooled to room temperature after cooling for 7 - 8 s. Others are the same as in Example 1.

[0052] The aluminum alloy forging rings produced by the above - mentioned schemes according to the same forging process are compared, and the properties of each example and comparative example are measured, and the performance test results of the aluminum alloy forging rings shown in Table 2 are obtained.

[0053] Table 2 Performance Test Results of Aluminum Alloy Forging Rings

[0054]

[0055] The calculation method for the difference in the three - dimensional elongation rate of the present invention is: longitudinal elongation rate - high - direction elongation rate.

[0056] Those of ordinary skill in the art should understand that: the discussion of any of the above embodiments is only exemplary and is not intended to imply that the protection scope of this application is limited to these examples; under the concept of this application, the technical features between the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of one or more embodiments of the present application as described above, and they are not provided in detail for the sake of brevity.

[0057] One or more embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of this application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of one or more embodiments of this application shall be included within the protection scope of this application.

Claims

1. A high-performance aluminum alloy, characterized in that, Comprising the following components by weight percentage: Si: 0.8 - 1.1%, Cu: 4.2 - 4.7%, Mn: 0.8 - 1.0%, Mg: 0.45 - 0.75%, Zr：0.03～0.04%， Er：0.015～0.02%， Fe: ≤0.2%; the balance is Al; The weight ratio of the Zr and Er is 2 - 3:1; The preparation method of the high-performance aluminum alloy is to mix the raw materials of the high-performance aluminum alloy, carry out melting, and then carry out casting and homogenization treatment to obtain the high-performance aluminum alloy; The casting is segmented casting, the initial cooling rate is 100°C / s, and the later cooling rate is 50°C / s.

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

3. A method for preparing a high-performance aluminum alloy according to any one of claims 1-2, characterized in that, Mix the raw materials of the high-performance aluminum alloy, carry out melting, and then carry out casting and homogenization treatment to obtain the high-performance aluminum alloy.

4. The preparation method according to claim 3, characterized in that, The temperature of the melting is 700 - 760°C.

5. The preparation method according to claim 4, characterized in that, The melting 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.

6. The preparation method according to claim 3, characterized in that, The temperature of the homogenization treatment is 480 - 500°C.

7. The preparation method according to claim 6, characterized in that, The holding time of the homogenization treatment is 24 - 36 h.

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