A high electrical conductivity aluminum-silicon alloy and its preparation method

Abstract

The present invention provides a high electrical conductivity aluminum-silicon alloy and a preparation method thereof, which relates to the technical field of preparation of non-ferrous metal alloy materials. The high electrical conductivity aluminum-silicon alloy comprises the following components in percentage by weight: Si: 4-6.5%, Sr: 0.02-0.05%, B: 0.008-0.015%, Fe: ≤0.15%, Al: the balance; the total sum of impurity elements ≤0.3%. The preparation method is as follows: (1) melting pure aluminum ingots; (2) heating to 780-800 °C, adding metallic silicon into the aluminum liquid, melting, skimming the slag, and sampling; (3) refining and degassing for 10-15 minutes, adding AlSr10 alloy to refine grains when there are still 5 minutes left in the refining and degassing process, standing, skimming the slag, and sampling; (4) adding AlB3 alloy, and casting to obtain the alloy. The aluminum-silicon alloy obtained by successively adding metallic silicon and AlSr10 and finally adding AlB3 into the aluminum melt has the characteristics of high electrical conductivity and low cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparation of non-ferrous metal alloy materials, and particularly relates to a high-conductivity aluminum-silicon alloy and a preparation method thereof. Background Art

[0002] The mechanical properties and electrical conductivity of aluminum alloys mainly depend on their alloy compositions and metallographic structures. However, alloy strengthening and improving electrical conductivity are two conflicting goals. Process methods for improving the tensile strength of alloys such as solid solution strengthening, precipitation strengthening, dispersion strengthening, and fine grain strengthening will all reduce the electrical conductivity. Because for alloys, the more crystal defects there are, the greater the lattice distortion, the greater the dislocation resistance, and the higher the strength; but the more crystal defects there are, the greater the electron scattering, and the lower the electrical conductivity. Currently, in the domestic and foreign standards for cast aluminum alloys, the electrical conductivity is generally below 25 MS / m (43% IACS), which cannot meet the higher electrical conductivity requirements put forward by customers, restricting the application of cast aluminum alloys in high-conductivity power and electrical structural components.

[0003] The non-patent literature "Research Progress of High-Conductivity Aluminum-Silicon Alloys [J]" (Yang Ying, Zhang Yu, Wang Yuxin, etc.. Metal Functional Materials, 2010, 17 (03): 96-99. DOI:10.13228 / j.boyuan.issn1005-8192.2010.03.014.) summarized the factors affecting the electrical conductivity of aluminum-silicon alloys, analyzed the effects of modification process, heat treatment and process control on improving the electrical conductivity of aluminum-silicon alloys, and prospected its future research and development directions. Chinese invention patent CN108531754B discloses a high-conductivity cast aluminum alloy, including the following components by weight percentage, Si: 4.5-6.5%, Mg: 0.35-0.45%, B: 0.005-0.015%, La: 0.08-0.15%, Sr: 0.008-0.02, Al: the balance; the weight percentage of impurity elements is, Fe: ≤0.15%, Ga: ≤0.03%, Zn: ≤0.03%, V: ≤0.007%, Cr: ≤0.005%, other impurities ≤0.01%, and the total of other impurities ≤0.1%. The preparation process flow of the high-conductivity cast aluminum alloy is: batching - melting aluminum - purifying aluminum liquid - transferring aluminum liquid - first alloying - slag removal and refining - second alloying - degassing and refining - composition adjustment - casting - heat treatment. The conductivity of the cast aluminum alloy products produced by using the high-conductivity cast aluminum alloy and its preparation method of the present invention is 46.5-50.7% IACS (27-29.4 MS / m) at room temperature, but rare earth element La is used in this patent, increasing the cost.

[0004] Therefore, there is an urgent need to provide an aluminum-silicon alloy with simple composition, low cost and high electrical conductivity and a preparation method thereof. Summary of the Invention

[0005] In view of the problems existing in the prior art, the present invention provides a high electrical conductivity aluminum-silicon alloy and a preparation method thereof. The high electrical conductivity aluminum-silicon alloy provided by the present invention is obtained by adding a certain amount of AlSr10 and AlB3 to an aluminum-silicon melt, and has an electrical conductivity of 28-29.7 MS / m at room temperature.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] The first aspect of the present invention is to provide a high electrical conductivity aluminum-silicon alloy, comprising the following components by weight percentage: Si: 4-6.5%, Sr: 0.02-0.05%, B: 0.008-0.015%, Fe: ≤0.15%, Al: the balance; the weight percentage of impurity elements is Cu: ≤0.05%, Mn: ≤0.005%, Mg: ≤0.015%, Cr: ≤0.005%, Ni: ≤0.005%, Zn: ≤0.02%, Ti: ≤0.01%, Pb: ≤0.0015%, Sn: ≤0.001%, other impurity elements ≤0.01%, and the total of other impurity elements ≤0.15%.

[0008] Preferably, the weight percentage of Si is 5.0-6.0%.

[0009] Preferably, the weight percentage of Sr is 0.02-0.04%.

[0010] Preferably, the weight percentage of B is 0.008-0.01%.

[0011] Preferably, the weight percentage ratio of Sr to B is 3-5:1.

[0012] Preferably, the electrical conductivity of the high electrical conductivity aluminum-silicon alloy at room temperature is 28-29.7 MS / m.

[0013] The second aspect of the present invention is to provide a preparation method of the above high electrical conductivity aluminum-silicon alloy, the preparation method comprising the following steps: (1) melting pure aluminum ingots to obtain aluminum liquid; (2) raising the temperature to 780-800 °C, adding metallic silicon to the aluminum liquid for conditioning, stirring and melting, skimming the slag, sampling to obtain silicon-aluminum melt; (3) refining and degassing for 10-15 minutes, adding AlSr10 alloy when 5 minutes remain in the refining and degassing, standing, skimming the slag, sampling to obtain Sr-containing silicon-aluminum melt; (4) adding AlB3 alloy to the Sr-containing silicon-aluminum melt, casting to obtain.

[0014] Preferably, during the refining and degassing in step (3), a refining agent is introduced, and the refining agent is carried by an inert gas.

[0015] Preferably, the addition amount of metallic silicon in the step (2) accounts for 4.0 - 6.5% of the mass percentage of the system.

[0016] Preferably, the addition amount of AlSr10 alloy in the step (3) accounts for 0.3 - 0.45% of the mass percentage of the system.

[0017] Preferably, the addition amount of AlB3 alloy in the step (4) accounts for 0.2 - 0.4% of the mass percentage of the system.

[0018] Compared with the prior art, the present invention has the following beneficial effects: (1) The aluminum - silicon alloy obtained by adding metallic silicon and AlSr10 successively to the aluminum melt and finally adding AlB3 has a high conductivity, and the conductivity is 28 - 29.7 MS / m; (2) The raw materials of the elements contained in the silicon - aluminum alloy of the present invention are easily available and the cost is low. Specific embodiments

[0019] Example 1

[0020] A high - conductivity aluminum - silicon alloy, the preparation steps are as follows: Melting 94 kg of pure aluminum ingots, raising the temperature to 780 °C, then adding 5.95 kg of metallic silicon for conditioning, stirring and melting, skimming the slag, sampling, performing refining and degassing for 10 min. When there are 5 min left in the refining and degassing process, adding 0.42 kg of AlSr10 alloy, standing, skimming the slag, sampling, adding 0.3 kg of AlB3 alloy, then lowering the temperature of the casting mold to about 100 °C, and casting to obtain. After testing, the high - conductivity aluminum - silicon alloy includes the following components by weight percentage: Si: 6.298%, Sr: 0.0294%, B: 0.0097%, Fe: 0.121%, Al: 93.3652%; The weight percentage of impurity elements is Cu: 0.039%, Mn: 0.004%, Mg: 0.01%, Cr: 0.0043%, Ni: 0.0046%, Zn: 0.018%, Ti: 0.0052%, Pb: 0.0011%, Sn: 0.0005%, and the total of other impurity elements is 0.09%.

[0021] Sampling and testing the prepared high - conductivity aluminum - silicon alloy, the conductivity at room temperature is 29.23 MS / m.

[0022] Example 2

[0023] Raw material composition: 96 kg of pure aluminum ingots, 4.23 kg of metallic silicon, 0.42 kg of AlSr10 alloy and 0.3 kg of AlB3 alloy.

[0024] A high electrical conductivity aluminum-silicon alloy is prepared as follows: 96 kg of pure aluminum ingots are melted, the temperature is raised to 800 °C, metallic silicon is added for conditioning, stirred and melted, slag is skimmed, a sample is taken, refined and degassed for 15 min. When there are 5 min left in the refining and degassing process, 0.42 kg of AlSr10 alloy is added for modification treatment, left standing, slag is skimmed, a sample is taken, 0.3 kg of AlB3 alloy is added, then the temperature of the casting mold is lowered to about 100 °C, and casting is carried out to obtain the alloy. After testing, the high electrical conductivity aluminum-silicon alloy contains the following components by weight percentage: Si: 4.134%, Sr: 0.0371%, B: 0.0104%, Fe: 0.115%, Al: 95.5444%; the weight percentage of impurity elements is: Cu: 0.039%, Mn: 0.004%, Mg: 0.012%, Cr: 0.0043%, Ni: 0.0047%, Zn: 0.018%, Ti: 0.005%, Pb: 0.0013%, Sn: 0.0008%, and the total of other impurity elements is 0.07%.

[0025] Samples of the prepared high electrical conductivity aluminum-silicon alloy are taken for testing, and the conductivity at room temperature is 29.51 MS / m.

[0026] Comparative Example 1

[0027] A high electrical conductivity aluminum-silicon alloy is prepared as follows: 94 kg of pure aluminum ingots are melted, the temperature is raised to 780 °C, then 5.95 kg of metallic silicon is added for conditioning, stirred and melted, slag is skimmed, a sample is taken, refined and degassed for 10 min. When there are 5 min left in the refining and degassing process, 0.42 kg of AlSr10 alloy is added, left standing, slag is skimmed, a sample is taken, 0.3 kg of AlCa10 alloy is added, then the temperature of the casting mold is lowered to about 100 °C, and casting is carried out to obtain the alloy.

[0028] The difference from Example 1 is that the AlB3 alloy in Example 1 is replaced with an equal amount of AlCa10.

[0029] After testing, the high electrical conductivity aluminum-silicon alloy contains the following components by weight percentage: Si: 6.214%, Sr: 0.0244%, Ca: 0.0198%, Fe: 0.112%, Al: 93.461%; the weight percentage of impurity elements is: Cu: 0.039%, Mn: 0.004%, Mg: 0.012%, Cr: 0.0043%, Ni: 0.0046%, Zn: 0.018%, Ti: 0.0051%, Pb: 0.0011%, Sn: 0.0007%, and the total of other impurity elements is 0.08%.

[0030] Samples of the prepared high electrical conductivity aluminum-silicon alloy are taken for testing, and the conductivity at room temperature is 26.37 MS / m.

[0031] Comparative Example 2

[0032] A high electrical conductivity aluminum - silicon alloy, the preparation steps are as follows: Melting 94 kg of pure aluminum ingots, raising the temperature to 780 °C, then adding 5.95 kg of metallic silicon for conditioning, stirring and melting, skimming the slag, sampling, performing refining and degassing for 10 min. When there are 5 min left in the refining and degassing process, adding 0.42 kg of AlCa10 alloy, standing, skimming the slag, sampling, adding 0.3 kg of AlB3 alloy, then lowering the temperature of the casting mold to about 100 °C, and casting to obtain the alloy.

[0033] The difference from Example 1 is that the AlSr10 alloy in Example 1 is replaced with an equal amount of AlCa10.

[0034] After testing, the high electrical conductivity aluminum - silicon alloy contains the following components by weight percentage: Si: 6.298%, Ca: 0.0414%, B: 0.0098%, Fe: 0.128%, Al: 93.3288%; The weight percentages of impurity elements are: Cu: 0.041%, Mn: 0.005%, Mg: 0.013%, Cr: 0.004%, Ni: 0.0042%, Zn: 0.026%, Ti: 0.0052%, Pb: 0.0011%, Sn: 0.0005%, and the total of other impurity elements is 0.094%.

[0035] Taking samples of the prepared high electrical conductivity aluminum - silicon alloy for testing, the conductivity at room temperature is 25.23 MS / m.

[0036] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than limiting the protection scope of the present invention. Any simple modification or equivalent replacement made by those of ordinary skill in the art to the technical solution of the present invention does not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A high electrical conductivity aluminum-silicon alloy, characterized in that: Comprising components with the following weight percentages: Si: 4 - 6.5%, Sr: 0.0294 - 0.05%, B: 0.008 - 0.0104%, Fe: ≤0.15%, and the balance being Al and impurities; the weight percentages of impurity elements are Cu: ≤0.05%, Mn: ≤0.005%, Mg: ≤0.015%, Cr: ≤0.005%, Ni: ≤0.005%, Zn: ≤0.02%, Ti: ≤0.01%, Pb: ≤0.0015%, Sn: ≤0.001%, other impurity elements ≤0.01%, and the total of other impurity elements ≤0.15%; the high electrical conductivity aluminum-silicon alloy is prepared through the following steps: (1) Melting pure aluminum ingots to obtain aluminum liquid; (2) Raising the temperature to 780 - 800 °C, adding metallic silicon to the aluminum liquid for conditioning, stirring and melting, skimming the slag, and sampling to obtain silicon-aluminum melt; (3) Refining and degassing, adding AlSr10 alloy, standing, skimming the slag, and sampling to obtain Sr-containing silicon-aluminum melt; (4) Adding AlB3 alloy to the Sr-containing silicon-aluminum melt and casting to obtain it; The electrical conductivity of the high electrical conductivity aluminum-silicon alloy at room temperature is 28 - 29.7 MS / m.

2. The high-conductivity aluminum-silicon alloy according to claim 1, wherein: The weight percentage of the said Si is 5.0 - 6.0%.

3. The high-conductivity aluminum-silicon alloy according to claim 1, wherein: The weight percentage of the said Sr is 0.02 - 0.04%.

4. The highly conductive aluminum-silicon alloy according to claim 1, wherein: The weight percentage of the said B is 0.008 - 0.01%.

5. The high-conductivity aluminum-silicon alloy according to claim 1, characterized in that: The weight percentage ratio of the said Sr and B is 3 - 5﹕1.

6. The high-conductivity aluminum-silicon alloy according to claim 1, characterized in that, During the refining and degassing in step (3), a refining agent is introduced. The refining agent uses an inert gas as a carrier, and the time for refining and degassing is 10 - 15 min.

7. The high-conductivity aluminum-silicon alloy according to claim 1, characterized in that, The addition amount of metallic silicon in step (2) accounts for 4.0 - 6.5% of the total mass of the raw materials.

8. The high-conductivity aluminum-silicon alloy according to claim 1, characterized in that, The addition amount of AlSr10 alloy in step (3) accounts for 0.3 - 0.45% of the total mass of the raw materials.

9. The high-conductivity aluminum-silicon alloy according to claim 1, characterized in that, The addition amount of AlB3 alloy in step (4) accounts for 0.2 - 0.4% of the total mass of the raw materials.