Preparation method of high-conductivity cast Al-Si-Mg-fullerene alloy and fullerene alloy

Abstract

The preparation method comprises the following steps: smelting 0.25%-0.5% of Mg, 1.5%-2.5% of Si, less than or equal to 0.5% of Fe, less than or equal to 0.2% of Sc, less than or equal to 0.15% of Zr, less than or equal to 0.025% of Ti, 0.002%-0.08% of B, less than or equal to 0.01% of Mn + Cr + V, 0.05%-0.2% of fullerene, less than or equal to 0.05% of single other impurities, less than or equal to 0.15% of the total amount of the impurities and the balance of aluminum in a temperature range of 720-750 DEG C; uniformly mixed precast blocks of Al-2Sc or Al-5Zr alloy powder and fullerene are pressed into the melt until the precast blocks are completely melted, and the alloy melt is subjected to casting molding to obtain a corresponding product. By adding the fullerene, the alloy has good casting formability, casting forming of a high-voltage switch product can be achieved, the hardness of the alloy is larger than or equal to 75 HBW and the conductivity is larger than or equal to 46% IACS by combining a specific two-stage heat treatment process, and by adding the fullerene, the thermal expansion coefficient of the alloy can be reduced, and the product size stability can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of aluminum alloys, and in particular to a preparation method of a highly conductive cast Al-Si-Mg-fullerene alloy and a fullerene alloy. Background Art

[0002] As the high-voltage power transmission industry develops towards high power and high current, the requirements for the conductivity of high-voltage switch materials continue to increase. At present, high-voltage switches are mainly produced using ZL101 aluminum alloy, which has good casting formability, but the conductivity after T6 heat treatment is only about 38% IACS. The temperature rise and loss increase during the transmission process, making it difficult to meet the requirements of high-current transmission. At present, the only way to meet the use requirements is to increase the switch diameter, but the large volume will bring problems such as difficulty in installation and use. The development of aluminum alloy materials with mechanical properties close to ZL101, conductivity ≥46% IACS and good casting properties is of great significance to the high-voltage power transmission industry.

[0003] ZL101 alloy is mainly composed of two elements, Si and Mg, with Si content of 6.5-7.5% and Mg content of 0.25-0.45%. The nano-Mg2Si precipitated during the aging process is the main strengthening phase of the material. After the Mg2Si phase is generated in the alloy, there is still a large amount of Si remaining. The remaining Si is mainly used to improve the casting properties of the material, and contributes little to the strength of the material, and will significantly reduce the electrical conductivity. Therefore, to improve the conductivity, it is necessary to reduce the Si content, but at the same time it also reduces the casting performance, resulting in poor fluidity, easy thermal cracking, large solidification shrinkage and other problems. How to reduce the Si content while ensuring the casting performance of the material is the key to the development of high-conductivity materials. Summary of the invention

[0004] The object of the present invention is to provide a new microalloyed Al-Si-Mg-fullerene alloy, which has good casting formability and can realize casting forming of high-voltage switch products. Combined with a specific two-stage heat treatment process, the alloy hardness is ≥75HBW and the electrical conductivity is ≥46%IACS.

[0005] According to one aspect of the present disclosure, the following technical solution is provided: a method for preparing a highly conductive cast Al-Si-Mg-fullerene alloy, the preparation method comprising the following steps:

[0006] S1, using industrial pure Al, pure Mg, Al-50Si, Al-20Fe, Al-2Sc powder, Al-5Zr powder, Al-10Ti, Al-3B and Al-Ti-B master alloys and high-purity fullerene as raw materials;

[0007] S2. The raw materials are mixed according to the following weight percentages: Mg 0.25% - 0.5%, Si 1.5% - 2.5%, the mass fraction of Mg and Si satisfies 1 / 10 ≤ Mg / Si ≤ 1 / 3, Fe ≤ 0.5%, Sc ≤ 0.2%, Zr ≤ 0.15%, Ti ≤ 0.025%, B 0.002% - 0.08%, Mn + Cr + V ≤ 0.01%, fullerene 0.05 - 0.2%, other impurities ≤ 0.05% each, total impurities ≤ 0.15%, and the balance is aluminum;

[0008] S3, melting the above raw materials at a temperature range of 720°C-750°C;

[0009] S4. After the solution is uniform, argon or C2Cl6 is used for refining and degassing, and appropriate amounts of Ti and B are added for microalloying treatment;

[0010] S5, then pressing the uniformly mixed prefabricated block of Al-2Sc or Al-5Zr alloy powder and fullerene into the melt until it is completely melted, and casting the alloy melt to obtain a corresponding product;

[0011] S6. subjecting the cast product to solid solution aging heat treatment.

[0012] According to the method for preparing a highly conductive cast Al-Si-Mg-fullerene alloy according to at least one embodiment of the present disclosure, the solution temperature in step S6 is 500-550° C. and the time is 2-15 hours.

[0013] According to the method for preparing a highly conductive cast Al-Si-Mg-fullerene alloy in at least one embodiment of the present disclosure, the aging in step S6 adopts a two-stage aging system, with the first stage aging at 180-240°C, 1-15h, and the second stage aging at 80-120°C, 12-24h, followed by furnace cooling or air cooling.

[0014] According to the method for preparing a highly conductive cast Al-Si-Mg-fullerene alloy in at least one embodiment of the present disclosure, the refining and degassing time is 30 minutes.

[0015] A highly conductive cast Al-Si-Mg-fullerene alloy, characterized by being an Al-Si-Mg-fullerene alloy prepared by the preparation method described in any one of claims 1 to 4.

[0016] Technical effects and advantages of the present invention:

[0017] The present invention makes the alloy have good casting formability by adding fullerene, can realize the casting forming of high-voltage switch products, and combines with a specific two-stage heat treatment process to make the alloy hardness ≥75HBW and the electrical conductivity ≥46%IACS. The addition of fullerene can reduce the thermal expansion coefficient of the alloy and improve the dimensional stability of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings illustrate exemplary embodiments of the present disclosure and together with the description serve to explain the principles of the present disclosure. These drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification.

[0019] Figure 1 This is a solidification structure morphology diagram of the alloy obtained in Example 1 of the present invention.

[0020] Figure 2 This is a solidification structure morphology diagram of the alloy obtained in Example 2 of the present invention.

[0021] Figure 3 This is a solidification structure morphology diagram of the alloy obtained in Example 3 of the present invention.

[0022] Figure 4 It is a test data chart of alloys prepared in the embodiments of the present invention and the comparative examples. DETAILED DESCRIPTION

[0023] For descriptive purposes, the present disclosure may use spatially relative terms such as "under," "beneath," "under," "above," "on," "higher," and "side (e.g., as in "sidewall")," to describe the relationship of one component to another (other) component as shown in the accompanying drawings. The spatially relative terms are intended to encompass different orientations of the device in use, operation, and / or manufacture in addition to the orientation depicted in the accompanying drawings. For example, if the device in the accompanying drawings is turned over, components described as "under" or "beneath" other components or features would then be positioned "above" the other components or features. Thus, the exemplary term "under" can encompass both the "above" and "below" orientations. Furthermore, the device may be otherwise oriented (e.g., rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein should be interpreted accordingly.

[0024] The present invention discloses a method for preparing a highly conductive cast Al-Si-Mg-fullerene alloy, the method comprising the following steps:

[0025] S1, using industrial pure Al, pure Mg, Al-50Si, Al-20Fe, Al-2Sc powder, Al-5Zr powder, Al-10Ti, Al-3B and Al-Ti-B master alloys and high-purity fullerene as raw materials;

[0026] S2. The raw materials are mixed according to the following weight percentages: Mg 0.25% - 0.5%, Si 1.5% - 2.5%, the mass fraction of Mg and Si satisfies 1 / 10 ≤ Mg / Si ≤ 1 / 3, Fe ≤ 0.5%, Sc ≤ 0.2%, Zr ≤ 0.15%, Ti ≤ 0.025%, B 0.002% - 0.08%, Mn + Cr + V ≤ 0.01%, fullerene 0.05 - 0.2%, other impurities ≤ 0.05% each, total impurities ≤ 0.15%, and the balance is aluminum;

[0027] S3, melting the above raw materials at a temperature range of 720°C-750°C;

[0028] S4. After the solution is uniform, use argon or C2Cl6 to refine and degas for 30 minutes, and add appropriate amounts of Ti and B for micro-alloying treatment;

[0029] S5, then pressing the uniformly mixed prefabricated block of Al-2Sc or Al-5Zr alloy powder and fullerene into the melt until it is completely melted, and casting the alloy melt to obtain a corresponding product;

[0030] S6. Subject the cast product to solution aging heat treatment to reduce the vacancy concentration of the aluminum matrix and synergistically improve the strength and electrical conductivity of the material.

[0031] Wherein, in step S6, the solution temperature is 500-550° C., the time is 2-15 h, and the aging adopts a two-stage aging system, the first stage is 180-240° C., 1-15 h, the second stage is 80-120° C., 12-24 h, and the furnace or air cooling is performed.

[0032] Embodiment 1

[0033] Industrial pure Al (99.85%), pure Mg, Al-50Si, Al-20Fe, Al-2Sc powder, Al-5Zr powder and fullerene are used as raw materials, and the raw materials are proportioned according to the target alloy composition Al-0.5Mg-1.5Si-0.1Fe-0.004(Sc+Zr)-0.05 fullerene. The industrial pure aluminum ingot is melted and heated to 750°C, and Al-50Si, Al-20Fe and pure Mg are added in sequence. After the melt is uniform, 0.5% C2Cl6 is used for refining and degassing. After standing for 20 minutes, 0.2% Al-5Ti-1B is added. After 15 minutes, a uniformly mixed prefabricated block of Al-2Sc and Al-5Zr alloy powder and fullerene is added according to the composition ratio. The mixture is kept warm for about 5 minutes. After the prefabricated block is completely melted, the melt is poured into an iron mold, and the product is obtained after solidification. The solidification structure photo of the alloy is shown in Figure 1 shown.

[0034] The casting was subjected to T6 heat treatment, solution treatment at 540°C for 10 h, water quenching, aging at 180°C for 4 h plus aging at 80°C for 24 h, and air cooling.

[0035] Embodiment 2

[0036] Industrial pure Al (99.85%), pure Mg, Al-50Si, Al-20Fe, Al-2Sc powder, Al-5Zr powder and fullerene are used as raw materials, and the raw materials are proportioned according to the target alloy composition Al-0.4Mg-1.6Si-0.15Fe-0.01(Sc+Zr)-0.1 fullerene. The industrial pure aluminum ingot is melted and heated to 750°C, and Al-50Si, Al-20Fe and pure Mg are added in sequence. After the melt is uniform, it is refined with argon for 30 minutes, and then 0.2% Al-5Ti-1B is added. After 15 minutes, a uniformly mixed prefabricated block of Al-2Sc and Al-5Zr alloy powder and fullerene is added according to the composition ratio. The mixture is kept warm for about 5 minutes. After the prefabricated block is completely melted, the melt is poured into a sand mold, and the product is obtained after solidification. The solidification structure photo of the alloy is shown in the figure. Figure 2 shown.

[0037] The casting was subjected to T6 heat treatment, solution treatment at 535°C for 4h, water quenching, aging at 220°C for 6h plus aging at 100°C for 24h, and air cooling.

[0038] Embodiment 3

[0039] Industrial pure Al (99.85%), pure Mg, Al-50Si, Al-20Fe, Al-2Sc powder, Al-5Zr powder and fullerene are used as raw materials, and the raw materials are proportioned according to the target alloy composition Al-0.4Mg-1.9Si-0.4Fe-0.006(Sc+Zr)-0.15 fullerene. The industrial pure aluminum ingot is melted and heated to 750°C, and Al-50Si, Al-20Fe and pure Mg are added in sequence. After the melt is uniform, it is refined with argon for 30 minutes, and then 0.2% Al-5Ti-1B is added. After 15 minutes, a uniformly mixed prefabricated block of Al-2Sc and Al-5Zr alloy powder and fullerene is added according to the composition ratio. The mixture is kept warm for about 5 minutes. After the prefabricated block is completely melted, the melt is poured into an iron mold, and the product is obtained after solidification. The solidification structure photo of the alloy is shown in the figure. Figure 3 As shown. Casting power industry main conductive products such as Figure 4 shown.

[0040] The casting was subjected to T6 heat treatment, solution treatment at 535°C for 6h, water quenching, aging at 220°C for 8h, and air cooling.

[0041] Comparative Example 1

[0042] The ZL101 (Al-7Si-0.35Mg) alloy ingot was melted and heated to 750°C, refined with argon for 30 minutes, and then 0.2% Al-5Ti-1B was added. After standing for 15 minutes, the melt was poured into an iron mold and the product was obtained after solidification.

[0043] The casting was subjected to T6 heat treatment, solution treatment at 535°C for 4h, water quenching, aging at 220°C for 4h, and air cooling.

[0044] Comparative Example 2

[0045] The 6061 (Al-1Mg-0.6Si-0.3Cu-0.2Cr-0.2Fe) alloy ingot was melted and heated to 750°C, refined with argon for 30 minutes, and then 0.2% Al-5Ti-1B was added. After standing for 15 minutes, the melt was poured into an iron mold and the product was obtained after solidification.

[0046] The casting was subjected to T6 heat treatment, solution treatment at 535°C for 4h, water quenching, aging at 220°C for 4h, and air cooling.

[0047] The products obtained in Example 1, Example 2, Example 3, Comparative Example 1 and Comparative Example 2 were tested for Brinell hardness and conductivity. The results are as follows: Figure 4 shown.

[0048] Fullerenes have excellent mechanical properties and electrical conductivity. Using them as alloy components is expected to synergistically improve the mechanical properties and electrical conductivity of Al-Si-Mg alloys and have a positive effect on casting performance: fullerene enrichment at the front of the solidification interface can inhibit dendrite growth, enhance the melt shrinkage feeding ability, and improve the alloy's fluidity and thermal cracking resistance.

[0049] according to Figure 4 From the data, it can be seen that the electrical conductivity of the alloy in the embodiment is significantly higher than that of the alloy in the comparative example.

[0050] In the description of this specification, the description with reference to the terms "one embodiment / method", "some embodiments / methods", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment / method or example are included in at least one embodiment / method or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment / method or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments / methods or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments / methods or examples described in this specification and the features of different embodiments / methods or examples, unless they are contradictory.

[0051] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0052] Those skilled in the art should understand that the above embodiments are only for the purpose of clearly illustrating the present disclosure, and are not intended to limit the scope of the present disclosure. For those skilled in the art, other changes or modifications may be made based on the above disclosure, and these changes or modifications are still within the scope of the present disclosure.

Claims

1. A method for preparing a highly conductive cast Al-Si-Mg-fullerene alloy, characterized in that: The preparation method comprises the following steps: S1, using industrial pure Al, pure Mg, Al-50Si, Al-20Fe, Al-2Sc powder, Al-5Zr powder, Al-10Ti, Al-3B and Al-Ti-B master alloys and high-purity fullerene as raw materials; S2. The raw materials are mixed according to the following weight percentages: Mg 0.25%-0.5%, Si 1.5%-2.5%, the mass fractions of Mg and Si satisfy 1 / 10≤Mg / Si≤1 / 3, Fe≤0.5%, Sc≤0.2%, Zr≤0.15%, Ti≤0.025%, B0.002%-0.08%, Mn+Cr+V≤0.01%, fullerene 0.05-0.2%, other impurities individually ≤0.05%, the total amount of impurities ≤0.15%, and the balance is aluminum; S3, melting the above raw materials at a temperature range of 720°C-750°C; S4. After the solution is uniform, argon or C2Cl6 is used for refining and degassing, and appropriate amounts of Ti and B are added for microalloying treatment; S5, then pressing the uniformly mixed prefabricated block of Al-2Sc or Al-5Zr alloy powder and fullerene into the melt until it is completely melted, and casting the alloy melt to obtain a corresponding product; S6. subjecting the cast product to solid solution aging heat treatment.

2. The method for preparing a highly conductive cast Al-Si-Mg-fullerene alloy according to claim 1, characterized in that: In the step S6, the solution temperature is 500-550° C. and the time is 2-15 hours.

3. The method for preparing a highly conductive cast Al-Si-Mg-fullerene alloy according to claim 1, characterized in that: In step S6, a two-stage aging system is adopted, with the first stage aging at 180-240° C. for 1-15 h, and the second stage aging at 80-120° C. for 12-24 h, followed by furnace cooling or air cooling.

4. The method for preparing a highly conductive cast Al-Si-Mg-fullerene alloy according to claim 1, characterized in that: The refining and degassing time is 30 minutes.

5. A highly conductive cast Al-Si-Mg-fullerene alloy, characterized in that: An Al-Si-Mg-fullerene alloy prepared by the preparation method according to any one of claims 1 to 4.

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