High-strength electromagnetic shielding copper alloy and method for manufacturing the same.

Abstract

The present invention relates to a high-strength electromagnetic shielding copper alloy and its manufacturing method, which belongs to the technical field of copper alloys. The chemical composition of the alloy is, in mass%, 3-9% Fe, 2-5% Ni, 0.2-0.5% Al, 0.01-0.20% rare earth metals, and the balance Cu and unavoidable impurities. By adding different alloying elements, the solubility of iron in the copper alloy is effectively improved, and the strength and electromagnetic shielding performance of the copper alloy are improved, resulting in a high-strength electromagnetic shielding copper alloy with electromagnetic shielding performance >110dB, electrical conductivity >50%IACS, and tensile strength >950MPa.

Description

Technical Field

[0001] The present invention relates to the technical field of copper alloys, and particularly to a high-strength electromagnetic shielding copper alloy and a manufacturing method thereof.

Background Art

[0002] High-strength electromagnetic shielding copper alloys have high conductivity, good heat dissipation, and electromagnetic shielding performance. They are mainly applied to ultra-LSI lead frames, high-efficiency broadband 5G communication devices, electronic countermeasure devices for national defense military equipment, radars, high-power microwave electron tubes, high-pulse magnetic field conductors, etc., and have broad prospects, so they have attracted great attention.

[0003] Conventional high-strength electromagnetic shielding copper alloys generally aim to improve the electromagnetic shielding performance itself, but it is difficult to improve the electromagnetic shielding performance and strength simultaneously. The main reasons for this are: (1) The solubility of iron in copper is small, and excess iron precipitates as coarse iron phases during the solidification process, deteriorating the quality of the casting and reducing the material performance; (2) The copper-iron liquid phase has a large positive heat of solution, and there is a metastable refractory gap at the liquidus line, resulting in a large variation in the composition between the center and the edge of the casting, which affects the performance of the copper-iron alloy. Therefore, it is an urgent task at present to achieve both high strength and high electromagnetic shielding performance.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The object of the present invention is to solve the technical problem that the high strength and high electromagnetic shielding performance of the high-strength electromagnetic shielding copper alloy in the prior art cannot be achieved simultaneously, and to provide a high-strength electromagnetic shielding copper alloy and a manufacturing method thereof.

Means for Solving the Problems

[0005] According to one aspect of the present invention, a high-strength electromagnetic shielding copper alloy is provided, having a chemical composition consisting of Fe 3-9%, Ni 2-5%, Al 0.2-0.5%, rare earth metals 0.01-0.20%, the remainder being Cu and unavoidable impurities, in mass%.

[0006] According to another aspect of the present invention, a method for producing the above-described high-strength electromagnetic shielding copper alloy is provided, comprising the steps of: arranging raw materials; vacuum melting the raw materials to obtain a copper alloy solution having the same chemical composition as the high-strength electromagnetic shielding copper alloy; casting the copper alloy solution to obtain an ingot; electromagnetic stirring of the ingot to obtain a copper alloy rod; vacuum arc remelting using the copper alloy rod as an electrode to obtain a homogenized ingot; forging, hot rolling and cold rolling the homogenized ingot to obtain a slab; and aging the slab to obtain the high-strength electromagnetic shielding copper alloy. [Brief explanation of the drawing]

[0007] To more clearly explain the technical aspects of the embodiments of the present invention, the following drawings necessary for describing the embodiments will be briefly described. However, the following drawings are only a part of the embodiments of the present invention, and it will be obvious to those skilled in the art that other drawings can be obtained based on these drawings without any creative effort. [Figure 1] A flowchart of a method according to several embodiments of the present invention is shown. [Figure 2] The metallographic diagrams of copper alloy rods according to several embodiments of the present invention are shown. [Figure 3] The following are metallographic diagrams according to several embodiments of the present invention. [Modes for carrying out the invention]

[0008] The advantages and various effects of the present invention will be more clearly demonstrated by describing specific embodiments and examples of the present invention below. Those skilled in the art will understand that these specific embodiments and examples are illustrative of the present invention and do not limit it.

[0009] Throughout this specification, unless otherwise specified, terms used herein should be understood as they are commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which this invention pertains. In case of any conflict, this specification shall prevail.

[0010] The various raw materials, reagents, instruments, and apparatus used in this invention may be obtained commercially or by existing methods, unless otherwise specified.

[0011] According to a typical embodiment of the present invention, a high-strength electromagnetic shielding copper alloy is provided having a chemical composition consisting of Fe 3-9%, Ni 2-5%, Al 0.2-0.5%, rare earth metals 0.01-0.20%, and the remainder being Cu and unavoidable impurities, in mass percent.

[0012] Embodiments of the present invention provide high-strength electromagnetic shielding copper alloys, which improve the strength and electromagnetic shielding performance of the copper alloy by effectively increasing the solubility of iron in the copper alloy through the addition of different alloying elements. In some embodiments, the addition of nickel forms a continuous solid solution in a face-centered cubic lattice with copper, improving strength and increasing the solubility of iron in the copper alloy. Furthermore, the addition of aluminum forms a compound with nickel, and the precipitation hardening effect of this compound significantly improves the strength of the alloy. In addition, the addition of rare earth metals can refine the crystal grains, increase the grain boundary area, improve strength, and effectively increase the magnetic reflection interface, thereby improving electromagnetic shielding performance.

[0013] The main chemical elements and their limitations mentioned above will be explained in detail. Regarding Fe, iron is a paramagnetic element that significantly enhances the low-frequency electromagnetic shielding effect of copper alloys and delays the recrystallization process of copper, thereby increasing its strength and hardness. However, the solubility of iron in copper is low, only 3.5% at 1050°C. If the maximum solid solubility is exceeded, segregation of alloy components becomes severe, affecting not only the uniformity of the copper alloy but also significantly reducing the strength and conductivity of the material. Therefore, the Fe content is controlled to 3-9%.

[0014] Regarding Ni, the nickel element forms an infinitely continuous solid solution with copper, exhibiting a face-centered cubic lattice, improving the strength of the copper alloy and increasing the solubility of iron in the copper alloy. Under conditions of 950°C, the solubility of iron in the copper-nickel alloy is increased by 4.8%, further improving the electromagnetic shielding performance and tensile strength of the copper alloy.

[0015] Regarding Al, the aluminum element forms a NiAl phase or Ni3Al phase with nickel. The NiAl phase or Ni3Al phase is distributed radially or in a network pattern in the copper alloy, exhibiting a significant precipitation hardening effect and greatly improving the strength of the electromagnetic shielding copper alloy. When the nickel / aluminum ratio is 8-10, the Ni content is controlled to 2-5% and the Al content to 0.2-0.5% to achieve optimal properties.

[0016] Regarding rare earth metals, since lanthanum, cerium, and yttrium, which are rare earth elements, hardly dissolve in copper, it is important to avoid adding too much rare earth element. Small amounts of rare earth metals have the effect of purifying the molten loop and improving the quality of copper alloy castings, so the content of rare earth metals is controlled to 0.01-0.20%.

[0017] In some embodiments, the rare earth metal may include one or more combinations of copper lanthanum alloys, copper cerium alloys, and copper yttrium alloys.

[0018] Regarding the reason for selecting the above alloy, lanthanum, cerium, and yttrium, which are rare earth elements, can refine the crystal grains of the copper alloy, increase the grain boundary area, improve the strength of the copper alloy, effectively increase the magnetic reflection interface, and enhance the electromagnetic shielding effect. On the other hand, since lanthanum, cerium, and yttrium, which are rare earth elements, are very easily oxidized, copper-lanthanum alloy, copper-cerium alloy, and copper-yttrium alloy are added as master alloys.

[0019] Another typical embodiment of the present invention provides a method for manufacturing the above high-strength electromagnetic shielding copper alloy. S1 of arranging raw materials; S2 of vacuum melting the raw materials to obtain a copper alloy liquid whose chemical composition is the same as that of the high-strength electromagnetic shielding copper alloy; S3 of casting the copper alloy melt to obtain an ingot; S4 of electromagnetic stirring the ingot to obtain a copper alloy round bar; S5 of performing vacuum arc remelting using the copper alloy round bar as an electrode to obtain a homogenized ingot; S6 of forging, hot rolling, and cold rolling the homogenized ingot to obtain a slab; S7 of aging the slab to obtain the high-strength electromagnetic shielding copper alloy.

[0020] In the method for manufacturing the above high-strength electromagnetic shielding copper alloy, the functions of each step are specifically as follows. Vacuum melting has the effect of removing gases in the melting of the copper alloy, reducing the oxidation loss of rare earth elements, and ensuring the accuracy of the material composition.

[0021] Electromagnetic stirring has the effect of reducing the component segregation of iron elements in the ingot and improving the homogeneity of the copper alloy material components during the casting of the copper alloy. The advantage of adopting electromagnetic stirring is that it is beneficial to the formation and growth of equiaxed crystals inside the copper alloy ingot, can improve the equiaxed crystal ratio of the ingot, refine the solidification structure, improve the inclusion distribution, and promote the homogenization of components. In electromagnetic stirring, it does not directly contact the molten metal and does not pollute the copper alloy melt.

[0022] Vacuum arc remelting further purifies copper alloy slabs, removes impurity elements, reduces component segregation, improves the homogeneity of the material components, and enhances the strength and electromagnetic shielding performance of the copper alloy. The advantage of using the vacuum arc remelting method is that, under vacuum and high-temperature conditions, nonmetallic inclusions such as oxides and nitrides in the consumable electrodes are dissociated or removed by carbon reduction, allowing for further purification. In addition, it becomes possible to remove gases, nonmetallic inclusions, and harmful low-melting-point impurities, improving performance variability in the longitudinal and transverse directions, ensuring the stability and uniformity of material properties, and dramatically improving physical properties such as plastic deformation performance, mechanical performance, and electromagnetic shielding performance.

[0023] Aging treatment removes processing distortion and improves the uniformity of performance.

[0024] In some embodiments, before the vacuum melting, the vacuum level is set to 10 -3 Pre-extraction is performed at Pa, and then argon is filled to a vacuum level of 0.1–0.9 Pa.

[0025] Regarding its function, the preliminary extraction is to efficiently evacuate the air inside the vacuum melting furnace and prevent oxidation, but the vacuum level is 10 -3 When the pressure reaches Pa, the boiling point of copper drops to 951°C, and a large amount of copper volatilizes during dissolution. Therefore, by filling the vacuum with argon gas to 0.1-0.9 Pa during dissolution, it is possible to ensure that the material does not oxidize and to avoid the loss of elements through volatilization.

[0026] In some embodiments, the ingot is left to stand for 5 to 20 seconds before electromagnetic stirring is performed.

[0027] The purpose of controlling the settling time is that if the settling time is too short, the molten metal becomes excessively superheated, making it prone to pitting and casting defects. However, if the settling time is too long, the ingot solidifies completely, and the stirring effect cannot be achieved. Therefore, the settling time should be controlled to 5 to 20 seconds.

[0028] In some embodiments, electromagnetic stirring is performed alternately in forward and reverse directions, the stirring frequency of electromagnetic stirring is 5 to 30 Hz, and the current of electromagnetic stirring is 200 to 300 A.

[0029] By alternating between forward and reverse rotation during electromagnetic stirring, the occurrence of internal cavities in the ingot due to single-mode stirring can be avoided. The effect of controlling the frequency of electromagnetic stirring is that as the frequency increases within this range, the electromagnetic stirring effect increases, and the grain size refinement effect becomes more pronounced. Below 5 Hz, the electromagnetic stirring frequency is too weak, and the effects of homogenization and refinement are not obtained. Above 30 Hz, the skin effect and eddy current effect become prominent, leading to a tendency for melt growth in the crystal grains and reducing the improvement effect of the solidification structure by electromagnetic stirring. In addition, the flow within the molten material gradually becomes stronger, resulting in turbulence, which reduces the uniformity of the initial phase distribution, i.e., the improvement effect of component segregation by electromagnetic stirring.

[0030] The reason for controlling the current in electromagnetic stirring is that, within this range, as the current increases, the electromagnetic field strength increases significantly, increasing the fluidity of the molten copper alloy, making microscopic temperature fluctuations larger, which is advantageous for homogenizing the composition. If the current is less than 200A, the electromagnetic force generated inside the casting is weak, the conversion of columnar crystals to equiaxed crystals is insufficient, and the homogenization effect is insufficient. However, if the current reaches 300A and the frequency is appropriate, further increasing the current will not cause any change in the structure and will instead lead to a waste of electrical energy.

[0031] In some embodiments, the pressure for vacuum arc remelting is 0.1 to 5 Pa, and the arc length for vacuum arc remelting is 25 to 80 mm.

[0032] The reason for controlling the pressure during vacuum arc remelting is that furnace pressure affects arc behavior and the quality of the copper alloy. If the residual pressure in the arc region increases to more than 5 Pa, it reaches the critical pressure region for glow discharge, which can lead to unstable arc combustion and even arc extinction.

[0033] The reason for controlling the arc length is that if the arc length is too short, short circuits occur frequently, and the quality of the ingot deteriorates. However, if the arc length is too long, the arc moves, damaging the equipment.

[0034] In some embodiments, when the copper alloy rod is used as an electrode, a gap layer of 50 to 100 mm is left around the copper alloy rod.

[0035] The purpose of leaving a gap layer is to ensure safety while providing a good channel for gas release.

[0036] In some embodiments, the starting temperature for the hot rolling is 1000-1020°C, the ending temperature for the hot rolling is 830-850°C, the strain rate for the hot rolling is 60% or more, and the strain rate for the cold rolling is 45-60%.

[0037] In some embodiments, the aging treatment temperature is 250-300°C, and the aging treatment duration is 24-72 hours.

[0038] Example 1 A high-strength electromagnetic shielding copper alloy is provided, the mass percentage of its chemical composition as shown in Table 1. Table 1: Chemical composition of the high-strength electromagnetic shielding copper alloy of Example 1 JPEG0007866063000001.jpg11170

[0039] The method for manufacturing the high-strength electromagnetic shielding copper alloy includes the following steps.

[0040] (1) Raw material arrangement A raw material is prepared consisting of, by weight, 4% iron, 2% nickel, 0.2% aluminum, 0.05% rare earth lanthanum metal, with the remainder being copper and other unavoidable impurities, of which the rare earth lanthanum is blended as a copper-lanthanum intermediate alloy.

[0041] (2) Vacuum induction melting Before placing the raw materials into the furnace, scale and oil stains are removed, the surfaces of the iron rods, electroplated copper plates, and electroplated nickel plates are polished to remove any coatings, and the crucible is fitted tightly at the top and loosely at the bottom to prevent cross-linking during charging. The iron rods, copper plates, and nickel plates are placed in the lower part of the crucible, and the aluminum ingot is placed in the upper part of the crucible. The crucible material is an alkali crucible, and the copper lanthanum alloy is placed in the secondary charging plate. After that, the inside of the mold is polished clean with sandpaper, and a release agent (boron nitride + alcohol) is applied to the inner wall. The lid of the vacuum furnace is closed, and the mechanical pump and Roots pump are opened in sequence to create a vacuum, and 10 -3 Once a vacuum of Pa is reached, the Roots pump and mechanical pump are closed, and argon gas is injected to a pressure of 0.4 Pa to initiate the melting process. At the start of the melting process, power is supplied at a low level of 40 kW for 10 minutes, then at 60 kW for 5 minutes, and finally at a high level of 95 kW until chemical cleaning is complete to prevent crosslinking during the material melting process. After the material has been chemically cleaned, high power is supplied again, and the crucible is tilted 2-3 times. When the temperature reaches approximately 1350°C, the power is reduced to 40 kW and maintained at this temperature for approximately 30 minutes to refine the alloy material. After the smelting period ends, the power is turned off to allow the mixture to cool and form a film. Fifteen minutes after the power outage, a thin film forms on the surface of the molten pool. At this point, copper lanthanum alloy is slowly and uniformly added, the molten pool is stirred with 95kW of power, the crucible is tilted two to three times, and the temperature is raised to 1300°C. This is then maintained for 10 minutes, and the power is reduced to 40kW to adjust the temperature. When the temperature reaches approximately 1200°C, casting is performed to obtain the ingot.

[0042] (3) Electromagnetic stirring casting After casting, the copper alloy ingot is left to stand for 10 seconds and then electromagnetically stirred. The electromagnetic stirring direction is cyclical, with forward rotation for 5 seconds and reverse rotation for 5 seconds. The electromagnetic stirring current is 200A and the electromagnetic stirring frequency is 10Hz, resulting in a copper alloy rod.

[0043] (4) Vacuum arc remelting By removing the coating from copper alloy rods obtained by electromagnetic stirring and casting, and using these as electrodes for vacuum arc remelting, gases and nonmetallic inclusions within the electromagnetically shielded copper alloy are removed, harmful impurities with low melting points are eliminated, variations in performance in the longitudinal and width directions are improved, good consistency, uniform composition and performance stability of the copper alloy are ensured, and physical properties such as plastic deformation performance, mechanical performance and electromagnetic shielding performance are significantly improved. The main process conditions for vacuum arc melting are a furnace pressure of 1 Pa, an arc length of 35 mm, a gap between the electrode and the crucible of 60 mm, and an initial melting voltage of 80 kW. After forming a molten pool, the melting power is increased to 120 kW, higher than the power specified for the main melting phase, in order to compensate for the chill effect at the bottom of the crucible. During melting, the power is kept at 90 kW until the end of melting to minimize shrinkage porosity and segregation at the top of the ingot, and finally hot topping is performed to obtain a homogenized ingot with a homogenized composition.

[0044] (5) Plastic deformation Homogenized ingots are forged to obtain forged products of the desired dimensions. After forging, the copper alloy is subjected to rolling deformation treatments, including hot rolling and cold rolling, to further increase the strength of the material. Hot rolling starts at a temperature of 950°C and ends at 830-850°C, with the strain rate controlled to 65%. Cold rolling is performed with the strain rate controlled to 50%, resulting in slabs.

[0045] (6) Prescription To remove processing distortion and improve performance uniformity, the slabs are subjected to aging treatment at a temperature of 250°C for a duration of 24 hours.

[0046] Example 2 The present invention provides a high-strength electromagnetic shielding copper alloy whose chemical composition mass percentages are shown in Table 2. Table 2: Chemical composition of the high-strength electromagnetic shielding copper alloy of Example 2 JPEG0007866063000002.jpg11170

[0047] The method for manufacturing the above-mentioned high-strength electromagnetic shielding copper alloy includes the following steps.

[0048] (1) Raw material arrangement A raw material is prepared consisting of 5.2% iron, 3.1% nickel, 0.3% aluminum, 0.07% cerium (a rare earth metal) by weight, with the remainder being copper and other unavoidable impurities. Of this, the rare earth cerium is blended as a copper-cerium intermediate alloy.

[0049] (2) Vacuum induction melting Before placing the raw materials into the furnace, scale and oil stains are removed, the surfaces of the iron rods, electroplated copper plates, and electroplated nickel plates are polished to remove any coatings, and the crucible is fitted tightly at the top and loosely at the bottom to prevent cross-linking during charging. The iron rods, copper plates, and nickel plates are placed in the lower part of the crucible, and the aluminum ingot is placed in the upper part of the crucible. The crucible material is an alkali crucible, and the copper lanthanum alloy is placed in the secondary charging plate. After that, the inside of the mold is polished clean with sandpaper, and a release agent (boron nitride + alcohol) is applied to the inner wall. The lid of the vacuum furnace is closed, and the mechanical pump and Roots pump are opened in sequence to create a vacuum, and 10 -3 Once a vacuum of Pa is reached, the Roots pump and mechanical pump are closed, and argon gas is injected to a pressure of 0.8 Pa to initiate the melting process. At the start of the melting process, power is supplied at a low level of 40 kW for 10 minutes, then at 60 kW for 5 minutes, and finally at a high level of 95 kW until chemical cleaning is complete to prevent crosslinking during the material melting process. After the material has been chemically cleaned, high power is supplied again, and the crucible is tilted 2-3 times. Once the temperature reaches approximately 1380°C, the power is reduced to 40 kW and maintained at this temperature for approximately 30 minutes to refine the alloy material. After the smelting period ends, the power is turned off to cool the mixture and allow a film to form. After a 15-minute blackout, a thin film forms on the surface of the molten pool. At this point, the copper lanthanum alloy is slowly and uniformly added, the molten loop is stirred with 95kW of power, the crucible is tilted 2-3 times, and the temperature is raised to 1350°C. This is held for 10 minutes, then the power is reduced to 40kW to adjust the temperature. When the temperature reaches approximately 1220°C, casting is performed to obtain the ingot.

[0050] (3) Electromagnetic stirring casting After casting, the copper alloy ingot is left to stand for 8 seconds and then electromagnetically stirred. The electromagnetic stirring direction is cyclical, with 8 seconds of forward rotation and 8 seconds of reverse rotation. The electromagnetic stirring current is 300A and the electromagnetic stirring frequency is 20Hz, resulting in a copper alloy rod.

[0051] (4) Vacuum arc remelting By removing the coating from copper alloy rods obtained by electromagnetic stirring and casting, and using these as electrodes for vacuum arc remelting, gases and nonmetallic inclusions within the electromagnetically shielded copper alloy are removed, harmful impurities with low melting points are eliminated, variations in performance in the longitudinal and width directions are improved, good consistency, uniform composition and performance stability of the copper alloy are ensured, and physical properties such as plastic deformation performance, mechanical performance and electromagnetic shielding performance are significantly improved. The main process conditions for vacuum arc melting are a furnace pressure of 0.5 Pa, an arc length of 40 mm, a gap between the electrode and the crucible of 60 mm, and an initial melting voltage of 80 kW. After forming a molten pool, the melting power is increased to 120 kW, higher than the power specified for the main melting phase, in order to compensate for the chill effect at the bottom of the crucible. During melting, the power is kept at 90 kW until the end of melting to minimize shrinkage porosity and segregation at the top of the ingot, and finally hot topping is performed to obtain a homogenized ingot with a homogenized composition.

[0052] (5) Plastic deformation Homogenized ingots are forged to obtain forged products of the desired dimensions. After forging, the copper alloy is subjected to rolling deformation treatments, including hot rolling and cold rolling, to further increase the strength of the material. For hot rolling, the starting temperature is controlled to 950°C, the ending temperature to 830-850°C, and the strain rate of hot rolling is controlled to 68%. For cold rolling, the strain rate is controlled to 55%, and slabs are obtained.

[0053] (6) Prescription To remove processing distortion and improve uniformity, the slabs are subjected to aging treatment at a temperature of 300°C for a duration of 24 hours.

[0054] Example 3 The present invention provides a high-strength electromagnetic shielding copper alloy whose chemical composition mass percentages are shown in Table 3. Table 3: Chemical composition of the high-strength electromagnetic shielding copper alloy of Example 3 JPEG0007866063000003.jpg11170

[0055] The method for manufacturing the above-mentioned high-strength electromagnetic shielding copper alloy includes the following steps.

[0056] (1) Raw material arrangement A raw material is prepared consisting of 6.3% iron, 4.2% nickel, 0.4% aluminum, 0.03% rare earth yttrium, with the remainder being copper and other unavoidable impurities, of which the rare earth yttrium is blended as a copper-yttrium intermediate alloy.

[0057] (2) Vacuum induction melting Before placing the raw materials into the furnace, scale and oil stains are removed, the surfaces of the iron rods, electroplated copper plates, and electroplated nickel plates are polished to remove any coatings, and the crucible is fitted tightly at the top and loosely at the bottom to prevent crosslinking during charging. The iron rods, copper plates, and nickel plates are placed in the lower part of the crucible, and the aluminum ingot is placed in the upper part of the crucible. The crucible material is an alkali crucible, and the copper yttrium alloy is placed in the secondary charging plate. After that, the inside of the mold is polished clean with sandpaper, and a release agent (boron nitride + alcohol) is applied to the inner wall. The lid of the vacuum furnace is closed, and the mechanical pump and Roots pump are opened in sequence to create a vacuum, and 10 -3Once a vacuum of Pa is reached, the Roots pump and mechanical pump are closed, and argon gas is injected to bring the vacuum to 0.8 Pa to initiate the melting process. At the start of the melting process, power is supplied at a low level of 40 kW for 10 minutes, then at 60 kW for 5 minutes, and finally at a high level of 95 kW until chemical cleaning is complete to prevent crosslinking during the material melting process. After the material has been chemically cleaned, high power is supplied again, and the crucible is tilted 2-3 times. When the temperature reaches approximately 1400°C, the power is reduced to 40 kW and maintained at this temperature for approximately 30 minutes to refine the alloy material. After the smelting period ends, the power is turned off to cool the mixture and allow a film to form. After a 15-minute blackout, a thin film forms on the surface of the molten pool. At this point, the copper lanthanum alloy is slowly and uniformly added, the molten pool is stirred with 95kW of power, the crucible is tilted 2-3 times, and the temperature is raised to 1380°C. This is held for 10 minutes, then the power is reduced to 40kW to adjust the temperature. When the temperature reaches approximately 1210°C, casting is performed to obtain the ingot.

[0058] (3) Electromagnetic stirring casting After casting, the copper alloy ingot is left to stand for 10 seconds and then electromagnetically stirred. The electromagnetic stirring direction is cyclical, with forward rotation for 5 seconds and reverse rotation for 5 seconds. The electromagnetic stirring current is 300A and the electromagnetic stirring frequency is 20Hz, resulting in a copper alloy rod.

[0059] (4) Vacuum arc remelting By removing the coating from copper alloy rods obtained by electromagnetic stirring and casting, and using these as electrodes for vacuum arc remelting, gases and nonmetallic inclusions within the electromagnetically shielded copper alloy are removed, harmful impurities with low melting points are eliminated, variations in performance in the longitudinal and width directions are improved, good consistency, uniform composition and performance stability of the copper alloy are ensured, and physical properties such as plastic deformation performance, mechanical performance and electromagnetic shielding performance are significantly improved. The main process conditions for vacuum arc melting are a furnace pressure of 2 Pa, an arc length of 35 mm, a gap between the electrode and the crucible of 55 mm, and an initial melting voltage of 75 kW. After forming a molten pool, the melting power is increased to 115 kW, higher than the power specified for the main melting phase, in order to compensate for the chill effect at the bottom of the crucible. During melting, the power is kept at 85 kW until the end of melting to minimize shrinkage porosity and segregation at the top of the ingot, and finally hot topping is performed to obtain a homogenized ingot with a homogenized composition.

[0060] (5) Plastic deformation Homogenized ingots are forged to obtain forged products of the desired dimensions. After forging, the copper alloy is subjected to rolling deformation treatments, including hot rolling and cold rolling, to further increase the strength of the material. For hot rolling, the starting temperature is controlled to 955°C, the ending temperature to 855°C, and the strain rate of hot rolling is controlled to 65% or higher. For cold rolling, the strain rate is controlled to 50%, and slabs are obtained.

[0061] (6) Prescription To remove processing distortion and improve uniformity, the slabs were subjected to aging treatment at a temperature of 280°C for a duration of 42 hours.

[0062] Comparative Example 1 This is a high-strength electromagnetic shielding copper alloy consisting of 20 wt% Fe, 10 wt% Ni, and the remainder Cu by weight, and its manufacturing method is the same as in Example 1.

[0063] Comparative Example 2 This is a high-strength electromagnetic shielding copper alloy consisting of Fe 10 wt%, Ni 10 wt%, Re 0.1 wt%, and the remainder being Cu, and its manufacturing method is the same as in Example 1.

[0064] Comparative Example 3 This is a high-strength electromagnetic shielding copper alloy consisting of 25 wt% Ni, 5 wt% Al, and the remainder Cu by weight, and its manufacturing method is the same as in Example 1.

[0065] Experimental Example 1 The electromagnetic shielding performance and tensile strength of the high-strength electromagnetic shielding copper alloys provided in Examples 1-3 and Comparative Examples 1-3 were measured, and the results are shown in the table below. JPEG0007866063000004.jpg36170

[0066] As can be seen from the table above, the high-strength electromagnetic shielding copper alloys provided in Examples 1 to 3 of the present invention are superior to those in Comparative Examples 1 to 3 in electromagnetic shielding performance, conductivity, and tensile strength, with electromagnetic shielding performance >110 dB, conductivity >50% IACS, and tensile strength >950 MPa.

[0067] The high-strength electromagnetic shielding copper alloy provided in embodiments of the present invention effectively improves the solubility of iron in the copper alloy by adding different alloying elements, thereby improving the strength and electromagnetic shielding performance of the copper alloy. In some embodiments, the addition of nickel improves strength and increases the solubility of iron in the copper alloy by forming a continuous solid solution with copper in a face-centered cubic lattice structure. Furthermore, the addition of aluminum forms a compound with nickel, and the precipitation hardening effect of this compound significantly improves the strength of the alloy. Furthermore, the addition of rare earth metals can refine the crystal grains, increase the grain boundary area and improve strength, and also effectively increase the magnetic reflection interface and improve electromagnetic shielding performance.

[0068] Finally, the terms “may include,” “may include,” or any other variation thereof are intended to cover non-exclusive inclusion, and it should be further understood that a process, method, item, or apparatus containing a list of elements may include not only those elements but also other elements not expressly enumerated, or elements specific to such a process, method, item, or apparatus. While preferred embodiments of the Invention have been described, those skilled in the art, having learned the basic creative concepts, can make further changes and modifications to these embodiments. Therefore, the appended claims are intended to be construed as encompassing the preferred embodiments, as well as all changes and modifications that fall within the scope of the Invention. It will be apparent to those skilled in the art that various changes and modifications of the Invention can be made without departing from the spirit and scope of the Invention. Therefore, such changes and modifications of the Invention should be construed as being included in the Invention, provided they fall within the scope of the claims of the Invention and the equivalent art.

Claims

1. A method for producing a high-strength electromagnetic shielding copper alloy having a chemical composition of mass% Fe 3-9%, Ni 2-5%, Al 0.2-0.5%, rare earth metals 0.01-0.20%, the remainder being Cu and unavoidable impurities, The aforementioned high-strength electromagnetic shielding copper alloy has an electromagnetic shielding performance of >110 dB, conductivity of >50% IACS, and tensile strength of >950 MPa. The steps include arranging the raw materials according to the chemical composition of the copper alloy, The steps include: obtaining a copper alloy solution by vacuum melting the aforementioned raw materials; The steps include: casting the copper alloy solution, letting the ingot stand for 5 to 20 seconds, and then electromagnetically stirring to obtain a copper alloy rod; The steps include: using the aforementioned copper alloy rod as an electrode to perform vacuum arc remelting to obtain a homogenized ingot; The steps include forging, hot rolling and cold rolling the homogenized ingot to obtain a slab, The step includes aging the slab to obtain the high-strength electromagnetic shielding copper alloy, Before the vacuum melting, the vacuum level of the vacuum melting furnace was set to 10 －３ Pre-extraction is performed at Pa, and then argon gas is filled into the vacuum furnace so that the vacuum level is 0.1 Pa to 0.9 Pa. The electromagnetic stirring alternates between forward and reverse rotation, the stirring frequency of the electromagnetic stirring is 5 to 30 Hz, and the current of the electromagnetic stirring is 200 to 300 A. The pressure for the vacuum arc remelting is 0.1 to 5 Pa, and the arc length for the vacuum arc remelting is 25 to 80 mm. The starting temperature for the hot rolling is 950 to 955°C, the ending temperature for the hot rolling is 830 to 850°C, the strain rate for the hot rolling is 60% or more, and the strain rate for the cold rolling is 45 to 60%. A method for manufacturing a high-strength electromagnetic shielding copper alloy, characterized in that the temperature of the aging treatment is 250 to 300°C and the duration of the aging treatment is 24 to 72 hours.

2. The method for producing a high-strength electromagnetic shielding copper alloy according to claim 1, characterized in that the rare earth metal includes one or more combinations of copper lanthanum alloy, copper cerium alloy, and copper yttrium alloy.

3. The method for manufacturing a high-strength electromagnetic shielding copper alloy according to claim 1, characterized in that when the copper alloy rod is used as an electrode, a gap layer of 50 to 100 mm remains around the copper alloy rod.

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