Aluminum alloy part, method for manufacturing the same, and copper-clad aluminum composite cable

Abstract

The application discloses an aluminum alloy piece, a preparation method thereof and a copper-coated aluminum composite cable, and relates to the technical field of aluminum alloy materials.The aluminum alloy piece comprises the following elements in percentage by mass: iron: 0.5-0.8%; copper: 0.15-0.3%; erbium: 0.3-0.5%; and the balance is aluminum.The erbium element is introduced into the aluminum alloy piece, so that the Al3Er phase is formed in the aluminum alloy piece, the Al3Er phase has a certain strengthening capacity, the thermal stability of the aluminum alloy piece can be improved, and the creep performance of the aluminum alloy piece under a high-temperature environment can be improved.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy materials technology, and in particular to an aluminum alloy part and its preparation method, and copper-clad aluminum composite cable. Background Technology

[0002] Copper-clad aluminum composite cables are widely used in the field of power transmission due to the high conductivity of copper and the lightweight properties of aluminum.

[0003] Among them, Al-Fe-Cu aluminum alloy parts are the mainstream material for aluminum cores. They rely on the acicular Al3Fe phase for reinforcement. However, when the temperature is greater than 150°C, this phase coarsens rapidly, cutting the aluminum matrix lattice to form stress concentration points. This leads to insufficient grain boundary slip resistance, which in turn causes copper-aluminum interface failure. The insufficient high-temperature creep resistance of Al-Fe-Cu aluminum alloy parts has become a key bottleneck restricting the long-term development of cables. Summary of the Invention

[0004] The main objective of this invention is to propose an aluminum alloy component and its preparation method, along with a copper-clad aluminum composite cable, aiming to solve the problem of insufficient creep resistance of aluminum alloy components under high-temperature conditions in the prior art.

[0005] To achieve the above objectives, the present invention provides an aluminum alloy part comprising the following elements by mass percentage: iron: 0.5-0.8%; copper: 0.15-0.3%; erbium: 0.3-0.5%; and the balance being aluminum.

[0006] In one embodiment, the ratio of iron to copper atoms is (1.95~2.05):1.

[0007] In one embodiment, the elements include the following mass percentages: iron: 0.55-0.6%; copper: 0.2-0.25%; erbium: 0.35-0.45%.

[0008] In one embodiment, the aluminum alloy component is an aluminum core of copper-clad aluminum wire.

[0009] This invention also discloses a method for manufacturing the aforementioned aluminum alloy part, comprising the following steps: S1. First, heat the aluminum source to obtain molten aluminum liquid; S2. Iron source, copper source and erbium source are added to the aluminum liquid in sequence, and a mixed metal liquid is obtained after melting. S3. The mixed molten metal is die-cast to obtain a casting rod; S4. Post-process the casting rod to obtain aluminum alloy parts.

[0010] In one embodiment, step S4 includes the following post-processing steps: Solution treatment step: heat the cast rod to 530~550°C and hold for 1.5~2.5 hours; The pre-aging treatment step involves heating the solution-treated casting rod to 195~205°C and holding it at that temperature for 4.5~5.5 hours. The final aging process involves heating the pre-aged casting to 310~320°C and holding it at that temperature for 4.5~5.5 hours.

[0011] In one embodiment, step S4 includes the following post-processing steps: Solution treatment step: heat the cast rod to 530~550°C and hold for 1.5~2.5 hours; The pre-aging treatment step involves heating the solution-treated casting rod to 195~205°C and holding it at that temperature for 4.5~5.5 hours. The final aging process involves first heating the pre-aged casting to 240-260°C and holding it at that temperature for 1.5-2.5 hours, and then holding it at 190-210°C for 9-11 hours.

[0012] In one embodiment, after the solution treatment step and before the pre-aging treatment step, the cast rod is water quenched to room temperature at a rate of ≥100°C / s.

[0013] In one embodiment, the casting rod is air-cooled after the pre-aging treatment step and before the final aging treatment step.

[0014] The present invention also discloses a copper-clad aluminum composite cable, wherein the copper-clad aluminum composite cable includes an aluminum core, and the aluminum core includes the aforementioned aluminum alloy component or an aluminum alloy component prepared according to the aforementioned preparation method.

[0015] In the technical solution of the present invention, erbium is introduced into the aluminum alloy parts to form the Al3Er phase. The Al3Er phase has a certain strengthening ability, which can improve the thermal stability of the aluminum alloy parts and improve the creep performance of the aluminum alloy parts under high temperature environment. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially. Furthermore, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, or solution B, or a solution where both A and B are satisfied simultaneously. In addition, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention. 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.

[0017] Copper-clad aluminum composite cables are widely used in the power transmission field due to the high conductivity of copper and the lightweight properties of aluminum. Among them, Al-Fe-Cu aluminum alloy components are the mainstream aluminum core material. Traditional Al-Fe-Cu aluminum alloy components rely on acicular Al3Fe phase for reinforcement. However, at temperatures above 150°C, this phase coarsens rapidly, causing the originally small acicular Al3Fe phase to gradually grow into large particles. Ultimately, the size of the Al3Fe phase increases significantly, even exceeding 1μm. This breaks the aluminum matrix lattice, forming stress concentration points, resulting in insufficient grain boundary slip resistance and a creep activation energy drop to 90kJ / mol (far below the lattice self-diffusion energy barrier of 145kJ / mol). This leads to copper-aluminum interface failure. The insufficient high-temperature creep resistance of Al-Fe-Cu aluminum alloy components has become a key bottleneck restricting the long-term development of cables.

[0018] In view of this, the present invention provides an aluminum alloy part comprising the following elements in mass percentage: iron: 0.5-0.8%; copper: 0.15-0.3%; erbium: 0.3-0.5%; and the balance being aluminum.

[0019] In the technical solution of the present invention, erbium is introduced into the aluminum alloy parts to form the Al3Er phase. The Al3Er phase has a certain strengthening ability, which can improve the thermal stability of the aluminum alloy parts and improve the creep performance of the aluminum alloy parts under high temperature environment.

[0020] In some embodiments of the present invention, the ratio of iron to copper atoms is (1.95-2.05):1.

[0021] In the technical solution of this invention, while limiting the mass percentage of each component, the ratio of iron to copper atoms is kept within the range of (1.95-2.05):1, utilizing the coherence between Al3Er and the aluminum matrix as the primary inducing phase. At this ratio, Al3Fe and Al2Cu tend to undergo heterogeneous nucleation on the Al3Er surface, forming a unique core-shell composite precipitate. This structure effectively reduces the interfacial energy and generates a 'solute dragging' effect, inhibiting the Ostwald ripening of Al3Er particles. This thermodynamically and kinetically ensures the size stability of the Al3Er nanophase within the 10-20 nm range, thereby improving the thermal stability of the aluminum alloy parts and enhancing their creep performance under high-temperature conditions.

[0022] In some embodiments of the present invention, the following elements of mass percentage are included: Iron: 0.55-0.6%; Copper: 0.2-0.25%; Erbium: 0.35-0.45%.

[0023] In the technical solution of the present invention, keeping the mass percentages of iron, copper and erbium within the above-mentioned range can make the size and distribution of the three-phase precipitates Al3Er, Al3Fe and Al2Cu more stable and uniform, and better improve the creep performance of aluminum alloy parts under high temperature environment.

[0024] In some embodiments of the present invention, the aluminum alloy component may be an aluminum core of a copper-clad aluminum wire. The aluminum core maintains high electrical conductivity while exhibiting strong high-temperature creep resistance, resulting in a more stable copper-aluminum interface in the prepared copper-clad aluminum wire.

[0025] The present invention also provides a method for preparing the above-mentioned aluminum alloy parts, comprising the following steps: S1. First, heat the aluminum source to obtain molten aluminum liquid; S2. Iron source, copper source and erbium source are added to the aluminum liquid in sequence, and a mixed metal liquid is obtained after melting. S3. The mixed molten metal is die-cast to obtain a casting rod; S4. Post-process the casting rod to obtain aluminum alloy parts.

[0026] In the technical solution of this invention, the aluminum source is heated to obtain molten aluminum liquid, ensuring that the aluminum liquid is completely melted; the iron source is added first because iron has low solubility in aluminum, and sufficient heat preservation time is required to prevent its aggregation; then the copper source is added; finally, the erbium source is added. The rare earth element erbium has a high burn-off rate, and its later addition can reduce volatilization loss at high temperatures and reduce the deviation between the actual composition and the target composition; the casting rod is post-treated to form a composite strengthening phase of Al3Er, Al3Fe, and Al2Cu, and the creep resistance and electrical conductivity are improved through composition control and post-treatment.

[0027] In some embodiments of the present invention, step S4 includes the following post-processing steps: Solution treatment step: heat the cast rod to 530~550°C and hold for 1.5~2.5 hours; The pre-aging treatment step involves heating the solution-treated casting rod to 195~205°C and holding it at that temperature for 4.5~5.5 hours. The final aging process involves heating the pre-aged casting to 310~320°C and holding it at that temperature for 4.5~5.5 hours.

[0028] In the technical solution of this invention, the solution treatment fully dissolves the solute atoms in the cast rod. Controlling the solution treatment time and temperature ensures uniform distribution of solute atoms and avoids segregation, preparing for the precipitation of strengthening phases in the subsequent aging treatment. In the pre-aging treatment stage, precise control of temperature and time promotes preferential nucleation of Al3Er phase anchoring points, achieving a nucleation density of 2×10⁻⁶. 4 per μm 3 If this step is omitted or there is a temperature control deviation, the Al3Er phase will become too coarse, making its size greater than 100nm and losing its strengthening effect. The final aging treatment causes Al3Er, Al3Fe, and Al2Cu to form a "core-shell" composite strengthening phase with Al3Er as the core and Al3Fe / Al2Cu as the shell, which significantly improves the grain boundary slip resistance and enhances the high-temperature creep resistance of aluminum alloy parts.

[0029] In some embodiments of the present invention, step S4 includes the following post-processing steps: Solution treatment step: heat the cast rod to 530~550°C and hold for 1.5~2.5 hours; The pre-aging treatment step involves heating the solution-treated casting rod to 195~205°C and holding it at that temperature for 4.5~5.5 hours. The final aging process involves heating the pre-aged casting to 240-260°C and holding it for 1.5-2.5 hours, followed by holding it at 190-210°C for 9-11 hours.

[0030] In the technical solution of this invention, the final aging treatment is a dual-temperature zone treatment. Al2Cu precipitation is activated at a high temperature of 240-260°C to reduce the copper residue in the cast rod, and then the Al3Er phase is refined at a low temperature of 190-210°C to make the precipitated phase distribution more uniform. If the holding time at 240-260°C in the final aging treatment is shortened, i.e., less than 1.5 hours, it will lead to insufficient Al2Cu precipitation, which will destroy the integrity of the "core-shell" composite strengthening phase with Al3Er as the core and Al3Fe / Al2Cu as the shell, resulting in a decrease in high-temperature creep resistance; it will also increase the copper residue in the solute, reducing electrical conductivity.

[0031] Comparing the two post-treatment methods, the first method has a higher final aging temperature, which may result in some coarsening of alloy grains. Therefore, the second method has better mechanical properties.

[0032] In some embodiments of the present invention, after the solution treatment step and before the pre-aging treatment step, the sample is water quenched to room temperature at a rate of ≥100°C / s.

[0033] In the technical solution of this invention, rapid cooling by water quenching suppresses the precipitation of atoms in the cast rod to form a coarse second phase, creating conditions for the precipitation of a fine and dispersed second phase during pre-aging treatment.

[0034] In some embodiments of the present invention, the casting rod is air-cooled after the pre-aging treatment step and before the final aging treatment step.

[0035] In the technical solution of this invention, the second phase that is stably precipitated by air cooling of the casting rod can be achieved at the same time, and the residual stress can be fully released to avoid deformation and cracking of the casting rod.

[0036] This invention also discloses a copper-clad aluminum composite cable, wherein the copper-clad aluminum composite cable includes an aluminum core, and the aluminum core comprises the aforementioned aluminum alloy component or an aluminum alloy component prepared according to the aforementioned preparation method. Therefore, this copper-clad aluminum composite cable has all the beneficial effects of the aforementioned aluminum alloy component or the aforementioned preparation method of the aluminum alloy component, which will not be elaborated further here.

[0037] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are only used to explain the present invention and are not intended to limit the present invention.

[0038] The aluminum alloy part of Example 1 is composed of the following elements by mass percentage: iron: 0.5%, copper: 0.15%, erbium: 0.3%, aluminum: 99.02%, wherein the atomic ratio of iron to copper is 1.95. The formula for calculating the atomic ratio of iron to copper is as follows: Atomic ratio of iron to copper = [W(Fe) / M(Fe)] / [W(Cu) / M(Cu)], where W(Fe) is the mass percentage of iron; M(Fe) is the relative molecular mass of iron, taken as 55.85; W(Cu) is the mass percentage of copper; M(Cu) is the relative atomic mass of copper, taken as 63.55. The aluminum alloy part is prepared by the following steps: 1) Preparation of casting rods: Prepare the corresponding raw materials according to the above mass percentages, heat the aluminum source to obtain aluminum liquid, add iron source, copper source and erbium source to the aluminum liquid to obtain metal mixture, and perform die casting on the metal mixture to obtain casting rod.

[0039] 2) Post-processing: The obtained casting rod was heated to 315°C and held for 5 hours for conventional aging treatment. After the treatment, the aluminum alloy part of Example 1 was obtained.

[0040] The aluminum alloy part of Example 2 is prepared in the same way as that of Example 1, except that the mass percentage of elements is different. See Table 1 for details.

[0041] The aluminum alloy part of Example 3 is prepared in the same way as that of Example 1, except that the mass percentage of elements is different. See Table 1 for details.

[0042] The aluminum alloy part of Example 4 is prepared in the same way as that of Example 1, except that the mass percentage of elements is different. See Table 1 for details.

[0043] The aluminum alloy part of Example 5 is prepared in the same way as that of Example 1, except that the mass percentage of elements is different. See Table 1 for details.

[0044] The aluminum alloy part of Example 6 is prepared in the same way as that of Example 1, except that the mass percentage of elements is different. See Table 1 for details.

[0045] The aluminum alloy part of Comparative Example 1 is prepared in the same way as that of Example 1, except that the mass percentage of elements is different, as shown in Table 1.

[0046] Examples 1-6 use the same conventional aging process, and their performance differences mainly come from the synergistic regulation of Fe, Cu and Er in the alloy composition.

[0047] Table 1. Aluminum alloy parts of Examples 1-6 and Comparative Example 1, element mass percentage

[0048] Example 7 is the same as Example 1 in terms of elemental mass percentages and casting rod preparation steps, except that the post-processing step (step 2) is different. The post-processing step is as follows: The obtained casting rod was solution treated at 530°C for 1.5 hours, and then water-quenched to room temperature at a rate of ≥100°C / s. The casting rod was then heated to 195°C and held for 4.5 hours to complete the pre-aging treatment, followed by air cooling. After air cooling, the casting rod was heated to 310°C and held for 4.5 hours to complete the final aging treatment. After furnace cooling, the aluminum alloy part was obtained.

[0049] Example 8 is the same as Example 2 in terms of elemental mass percentages and casting rod preparation steps, except that the post-processing steps in step 2) are different. The post-processing steps are as follows: The obtained casting rod was solution treated at 540°C for 2 hours, and then water quenched to room temperature at a rate of ≥100°C / s. The casting rod was heated to 200°C and held for 5 hours to complete the pre-aging treatment, and then air-cooled. After air cooling, the casting rod was heated to 315°C and held for 5 hours to complete the final aging treatment. After furnace cooling, aluminum alloy parts were obtained.

[0050] Example 9 is the same as Example 3 in terms of elemental mass percentages and casting rod preparation steps, except that the post-processing step (step 2) is different. The post-processing step is as follows: The obtained casting rod was solution treated at 550°C for 2.5 hours, and then water-quenched to room temperature at a rate of ≥100°C / s. The casting rod was then heated to 205°C and held for 5.5 hours to complete the pre-aging treatment, followed by air cooling. After air cooling, the casting rod was heated to 320°C and held for 5.5 hours to complete the final aging treatment. After furnace cooling, the aluminum alloy part was obtained.

[0051] Example 10 is the same as Example 4 in terms of elemental mass percentages and casting rod preparation steps, except that the post-processing step (step 2) is different. The post-processing step is as follows: The obtained casting rod was solution treated at 530°C for 1.5 hours, and then water quenched to room temperature at a rate of ≥100°C / s. The casting rod was heated to 195°C and held for 4.5 hours to complete the pre-aging treatment. After air cooling, it was first held at 240°C for 1.5 hours, and then held at 190°C for 9 hours to complete the final aging treatment. After furnace cooling, aluminum alloy parts were obtained.

[0052] Example 11 is the same as Example 5 in terms of elemental mass percentages and casting rod preparation steps, except that the post-processing step (step 2) is different. The post-processing step is as follows: The obtained casting rod was solution treated at 540°C for 2 hours, and then water quenched to room temperature at a rate of ≥100°C / s. The casting rod was heated to 200°C and held for 5 hours to complete the pre-aging treatment. After air cooling, it was first treated at 250°C for 2 hours, and then at 200°C for 10 hours to complete the final aging treatment. After furnace cooling, aluminum alloy parts were obtained.

[0053] Example 12 and Example 6 have the same elemental mass percentages and casting rod preparation steps, the difference being that the post-processing step 2) is different. The post-processing step is as follows: The obtained casting rod was solution treated by holding it at 550°C for 2.5 hours, and then water-quenched to room temperature at a rate of ≥100°C / s. The casting rod was then heated to 205°C and held for 5.5 hours to complete the pre-aging treatment. After air cooling, it was first treated by holding it at 260°C for 2.5 hours, and then by holding it at 210°C for 11 hours to complete the final aging treatment. After furnace cooling, the aluminum alloy part was obtained.

[0054] The post-processing parameters for the aluminum alloy parts in Examples 7 to 12 are shown in Table 2.

[0055] Table 2. Post-processing parameters for aluminum alloy parts in Examples 7 to 12

[0056] The aluminum alloy parts prepared in Examples 1 to 12 and Comparative Example 1 were subjected to electrical conductivity and creep rate tests. The electrical conductivity test was performed according to ASTM B193 / B193M standards, and the creep rate test was performed according to ASTM E139 standards. The results are shown in Table 3.

[0057] Table 3 Performance test results of Examples 1 to 12 and Comparative Examples 1 to 1

[0058] As shown in Table 3, Examples 1 to 6 have lower creep rates and higher electrical conductivity than Comparative Example 1. This indicates that by simultaneously controlling the mass percentage of iron at 0.5-0.8%, copper at 0.15-0.3%, erbium at 0.3-0.5%, and the balance being aluminum, the electrical conductivity of the aluminum alloy parts can be improved and the creep rate reduced.

[0059] Compared to Examples 1 to 6, Examples 7 to 12, using the post-processing preparation method in this scheme, further improve the conductivity and further reduce the creep rate.

[0060] In summary, this solution first improves the high-temperature creep resistance and electrical conductivity of aluminum alloy parts by adjusting the mass percentage and atomic ratio of each element. Then, it further enhances these properties through specific post-treatment steps: solution treatment, pre-aging treatment, and final aging treatment. The entire technical solution achieves a synergistic improvement in creep resistance and electrical conductivity under industrially feasible conditions through precise matching of composition control and post-treatment.

[0061] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included in the patent protection of the present invention.

Claims

1. An aluminum alloy part, characterized in that, Includes elements with the following mass percentages: Iron: 0.5-0.8%; Copper: 0.15-0.3%; Erbium: 0.3-0.5%; and, The balance is aluminum.

2. The aluminum alloy part as described in claim 1, characterized in that, The atomic ratio of iron to copper is (1.95~2.05):

1.

3. The aluminum alloy part as described in claim 2, characterized in that, Includes elements with the following mass percentages: Iron: 0.55-0.6%; Copper: 0.2-0.25%; Erbium: 0.35-0.45%.

4. The aluminum alloy part according to any one of claims 1 to 3, characterized in that, The aluminum alloy component is an aluminum core made of copper-clad aluminum wire.

5. A method for preparing an aluminum alloy part as described in any one of claims 1 to 3, characterized in that, Includes the following steps: S1. First, heat the aluminum source to obtain molten aluminum liquid; S2. Iron source, copper source and erbium source are added to the aluminum liquid in sequence, and a mixed metal liquid is obtained after melting. S3. The mixed molten metal is die-cast to obtain a casting rod; S4. Post-process the casting rod to obtain aluminum alloy parts.

6. The method for preparing aluminum alloy parts as described in claim 5, characterized in that, In step S4, the post-processing includes the following steps in sequence: Solution treatment step: heat the cast rod to 530~550°C and hold for 1.5~2.5 hours; The pre-aging treatment step involves heating the solution-treated casting rod to 195~205°C and holding it at that temperature for 4.5~5.5 hours. The final aging process involves heating the pre-aged casting to 310~320°C and holding it at that temperature for 4.5~5.5 hours.

7. The method for preparing aluminum alloy parts as described in claim 5, characterized in that, In step S4, the post-processing includes the following steps in sequence: Solution treatment step: heat the cast rod to 530~550°C and hold for 1.5~2.5 hours; The pre-aging treatment step involves heating the solution-treated casting rod to 195~205°C and holding it at that temperature for 4.5~5.5 hours. The final aging process involves first heating the pre-aged casting to 240-260°C and holding it at that temperature for 1.5-2.5 hours, and then holding it at 190-210°C for 9-11 hours.

8. The method for preparing aluminum alloy parts as described in claim 5 or 6, characterized in that, After the solution treatment step and before the pre-aging treatment step, the cast rod is water quenched to room temperature at a rate of ≥100°C / s.

9. The method for preparing aluminum alloy parts as described in claim 5 or 6, characterized in that, After the pre-aging treatment step and before the final aging treatment step, the casting rod is air-cooled.

10. A copper-clad aluminum composite cable, characterized in that, The copper-clad aluminum composite cable includes an aluminum core, and the aluminum core includes an aluminum alloy component as described in any one of claims 1 to 4 or an aluminum alloy component prepared by the preparation method according to any one of claims 5 to 9.

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