High-strength high-conductivity copper alloy based on micro-alloying solid solution strengthening and preparation method thereof
By using microalloying solid solution strengthening, a copper alloy with high strength, high elongation, and high conductivity was prepared, solving the problem of difficulty in balancing strength, plasticity, high-temperature stability, and conductivity in existing technologies, and realizing the application of low-cost, high-performance copper alloys.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SOUTHWEAT UNIV OF SCI & TECH
- Filing Date
- 2026-03-27
- Publication Date
- 2026-06-02
AI Technical Summary
Existing high-strength, high-conductivity copper alloys are difficult to balance in terms of strength, plasticity, high-temperature stability, and conductivity, and are also expensive. The civilian market lacks alloy grades that combine low cost, high strength, high conductivity, and high heat resistance.
By rationally selecting microalloying components of 0.2%~0.4% Zn, 0.2%~0.4% Mg, and 0.05%~0.1% Ti, and through processes such as medium-frequency induction melting, hot rolling, and cold rolling, a copper alloy with high strength, high elongation, and high conductivity was prepared.
It achieves comprehensive performance of copper alloy with ultimate tensile strength of 580MPa~620MPa, elongation of 2%~4%, hardness of 160HV~170HV, and conductivity of 60%IACS~62%IACS, thereby reducing raw material costs.
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Figure CN122128573A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to high-strength, high-conductivity copper alloys based on microalloy solid solution strengthening and their preparation methods, belonging to the field of copper alloy technology. Background Technology
[0002] High-strength, high-conductivity copper alloys are widely used in aerospace, high-power electronic devices, and advanced nuclear energy due to their excellent mechanical properties, good high-temperature stability, and electrical conductivity. Generally, HSHC alloys have a UTS of over 600 MPa and a conductivity of over 60% IACS. Typical examples of these alloys are Cu-Sn-P, Cu-Fe-P, Cu-Ni-Si, and Cu-Cr-Zr. Among them, the widely used high-strength, high-conductivity copper alloy system is chromium-zirconium copper (Cu-Cr-Zr system), whose core chemical composition is Cu-Cr (0.3%~1.0%)-Zr (0.05%~0.3%). Through the precipitation of Cr-rich phase and Cu5Zr intermetallic compounds in the nanoscale second phase, taking grade C18150 strip as an example, the tensile strength of this alloy is about 540 MPa~640 MPa, the elongation after fracture is about 6%~25%, the hard state is ≥6%, the semi-hard state is ≥15%, and the softening temperature can reach 550℃. However, the high cost of its raw materials limits its widespread application. For example, the raw material cost of the mainstream civilian Cu-Fe-P alloy (C19400) is only 60% to 70% of that of the Cu-Cr-Zr alloy (C18150) of the same specifications. Current research and development of such copper alloys mainly focuses on adjusting the types and contents of alloying elements and improving heat treatment processes to optimize the microstructure and properties of the alloy. However, the strength, plasticity, high-temperature stability, and electrical conductivity of copper alloys usually cannot be simultaneously achieved.
[0003] Furthermore, the high-strength, high-conductivity copper alloys currently widely used in the civilian sector are mainly Cu-Fe-P based, with a main chemical composition of Cu-Fe (2%~3%)-P (0.01%~0.15%). The high Fe content and stringent preparation process requirements result in a relatively high overall cost. Taking grade C19400 strip as an example, the conductivity of this alloy is 60% IACS, the hard-state tensile strength is about 415MPa-485MPa, the elongation after fracture is about 5%, and the softening temperature is about 480℃-500℃. Its tensile strength is insufficient to meet the performance requirements of some electronic devices.
[0004] Current research on high-strength and high-conductivity copper alloys mainly focuses on commercial systems such as Cu-Fe-P and Cu-Ni-Si. Research on microalloyed systems mainly focuses on the strengthening mechanism under high alloy content. There is insufficient research on the synergistic regulation of strength, plasticity, high-temperature stability and conductivity in microalloyed systems. There is a serious lack of suitable grades in the civilian market that combine low cost, high strength, high conductivity and high heat resistance. Summary of the Invention
[0005] To overcome the above-mentioned defects of the prior art, the present invention provides a high-strength and high-conductivity copper alloy based on microalloy solid solution strengthening and its preparation method. By rationally selecting the alloy composition and further controlling the heat treatment process, the copper alloy has excellent properties of high strength, high elongation, high hardness and high conductivity.
[0006] The technical solution adopted in this invention is: a method for preparing high-strength, high-conductivity copper alloys based on microalloy solid solution strengthening, comprising the following steps:
[0007] Step 1: Prepare the raw materials for the copper alloy. The raw materials, by mass percentage, include 0.2%~0.4% Zn, 0.2%~0.4% Mg, 0.05%~0.1% Ti, and the balance is Cu. Step 2: Melt the prepared raw materials. After melting pure Cu, first add Ti, stir and melt evenly, then add Mg and Zn, stir and melt evenly again, then add cryolite, stir and skim off the slag, keep warm for a period of time and then remove from the furnace. Step 3: Pour the molten alloy into a mold and air cool it. After it has completely cooled, you will get a cast copper alloy part. Step 4: The casting is subjected to high-temperature solution treatment, then hot-rolled, and water-quenched to obtain hot-rolled sheet metal; Step 5: Cold roll the hot-rolled sheet to obtain a rough-rolled sheet; Step Six: Soften and anneal the rough-rolled sheet to allow it to fully recrystallize; Step 7: Cold roll the sheet material to obtain a precision-rolled sheet material; Step 8: Perform stress-relief annealing on the precision-rolled sheet to obtain a high-strength, high-conductivity copper alloy (sheet).
[0008] Preferably, in step two, a medium-frequency induction melting furnace is used to melt the prepared raw materials.
[0009] Preferably, in step two, the smelting is carried out with charcoal covering, a molybdenum crucible is used, and cryolite is used as a flux.
[0010] Preferably, the melting temperature in step two is 1100℃~1500℃.
[0011] Preferably, in step three, the mold is a graphite mold, and the mold is dried and dehydrated before casting (this can be done in an electric furnace), and then zinc oxide is coated on the inner wall of the mold.
[0012] Preferably, in step four, the casting is first milled and then subjected to high-temperature solution treatment.
[0013] Preferably, the high-temperature solution treatment in step four is performed at a temperature of 800℃~850℃, and the holding time is 1 hour.
[0014] Preferably, in step four, the hot rolling process employs multi-pass rolling.
[0015] Furthermore, the single-pass processing rate of hot rolling is 15%~20%, and the total deformation is 70%~90%.
[0016] Preferably, the termination temperature of hot rolling in step four is 650℃~700℃.
[0017] Preferably, in step five, the hot-rolled sheet is first milled, and then the sheet is cold-rolled.
[0018] Preferably, in step five, the cold rolling process employs multi-pass rolling.
[0019] Preferably, in step five, the single deformation amount of cold rolling is 2% to 5%, and the total deformation amount is 45% to 75%.
[0020] Preferably, in step five, the thickness of the rough-rolled plate is 1.0 mm to 2.5 mm.
[0021] Preferably, in step six, the rough-rolled sheet is first milled and then softened and annealed.
[0022] Preferably, the softening annealing temperature in step six is 400℃~630℃, and the holding time is 2h~6h.
[0023] Furthermore, the softening annealing temperature is 450℃, and the holding time is 6 hours.
[0024] Preferably, in step seven, the sheet material is first milled and then cold-rolled.
[0025] Preferably, in step seven, the cold rolling process employs multi-pass rolling.
[0026] Furthermore, in step seven, the single deformation amount of cold rolling is 2% to 5%, and the total deformation amount is 75% to 90%.
[0027] Preferably, the thickness of the precision-rolled plate is 0.2mm to 0.4mm.
[0028] Preferably, in step eight, the precision-rolled sheet is first milled and then subjected to stress-relieving annealing.
[0029] Preferably, the stress-relief annealing temperature in step eight is 300℃~450℃, and the holding time is 1h~3h.
[0030] Furthermore, the stress-relief annealing temperature is 300℃, and the holding time is 1 hour.
[0031] Steps three through five can be replaced by continuous casting and rolling processes.
[0032] The high-strength, high-conductivity copper alloy based on microalloy solid solution strengthening is prepared by any of the preparation methods of the high-strength, high-conductivity copper alloy based on microalloy solid solution strengthening disclosed in this invention.
[0033] Preferably, the alloy grains of the high-strength, high-conductivity copper alloy based on microalloy solid solution strengthening are equiaxed.
[0034] The beneficial effects of this invention are: (1) This invention, through the rational selection of alloy composition and further control of heat treatment process, successfully prepared a copper alloy with high strength, high elongation, and high conductivity while achieving micro-multi-component synergistic alloying and low-damage solid solution strengthening. After annealing, the alloy undergoes complete recrystallization, the fibrous structure transforms into equiaxed crystals, and the disappearance of high-density dislocations significantly improves conductivity. Fine grain strengthening and solid solution strengthening enable it to maintain high strength. The prepared copper alloy has an ultimate tensile strength of 580MPa~620MPa, an elongation of 2%~4%, a hardness of 160HV~170HV, and a conductivity of 60%IACS~62%IACS. The hot rolling, rough rolling, and finish rolling deformation processes used in material forming are mature and easy to control, and the preparation process has universal applicability.
[0035] (2) This invention improves the tensile strength of copper alloys while maintaining high conductivity by adding trace amounts of Zn (134 pm, size difference 5%), Mg (160 pm, size difference 25%), and Ti (147 pm, size difference 14.8%), which have atomic radii larger than Cu, to the Cu matrix. At 450℃ aging, the solid solubility of Zn is about 39%. Adding 0.2%~0.4% Zn can completely dissolve the Zn, thereby improving strength, reducing stacking fault energy, and improving cold workability through solid solution strengthening. 0.2%~0.4% Mg is almost completely dissolved, providing a strong solid solution strengthening effect due to its large size difference. At the same time, the strong deoxidation effect improves the purity of the matrix and pins the grain boundaries, thereby improving the resistance to high-temperature softening. 0.05%~0.1% Ti is also completely dissolved. In addition to solid solution strengthening, it can also significantly refine the grains and has minimal impact on conductivity. The trace addition of the three elements achieves multiple functions at the atomic scale, including purifying the matrix, controlling defects, refining grains, and strengthening the interface, resulting in copper alloys exhibiting comprehensive properties of high conductivity (60% IACS~62% IACS) and high tensile strength (580MPa~620MPa). Attached Figure Description
[0036] Figure 1 This is a flowchart of the preparation method of high-strength and high-conductivity copper alloy based on microalloy solid solution strengthening according to the present invention; Figure 2 This is a graph showing the change in hardness of the processed sheet material after softening annealing (450℃ / 6h) in Embodiment 1 of the present invention under different deformation amounts (target thickness) as a function of deformation amount. Figure 3 This is a comparison of the engineering stress-strain tensile curves of the process plate after softening annealing (450℃ / 6h) and the plate after precision rolling (CR3 (0.3)) in Embodiment 1 of the present invention. Figure 4 These are metallographic and EDS images of Embodiment 1 of the present invention. Detailed Implementation
[0037] See Figure 1 This invention discloses a method for preparing high-strength, high-conductivity copper alloys based on microalloy solid solution strengthening, comprising the following steps: Step 1: Batching: Prepare the raw materials for the copper alloy. The raw materials, by mass percentage, include 0.2%~0.4% Zn, 0.2%~0.4% Mg, 0.05%~0.1% Ti, and the balance is Cu; Step 2: Smelting: The prepared raw materials are smelted in a medium-frequency induction furnace. Charcoal is used for covering during smelting, a molybdenum crucible is used, and cryolite is used as a flux. After the pure Cu is melted, Ti is added first, and the mixture is kept at a certain temperature for a period of time (usually 0.5h~2h) and stirred to make the fusion uniform. Then, low-melting-point Mg and Zn are added and stirred to make the fusion uniform. Cryolite is added, and the mixture is stirred to remove slag. The mixture is kept at a certain temperature for a period of time (usually 10min~30min) and then taken out of the furnace. Step 3: Casting: Using a graphite mold, the mold is dried and dehydrated in an electric furnace before casting. Then, zinc oxide is coated on the inner wall of the mold. The molten alloy is poured into the mold and air-cooled. After complete cooling, the copper alloy casting is obtained. Step 4: Hot rolling: Before hot rolling, the casting is milled, then subjected to high-temperature solution treatment, and then hot rolled. The hot rolling process is multi-pass rolling, and the hot-rolled plate is obtained after water quenching. Step 5: Rough rolling: The hot-rolled sheet is cold-rolled to obtain a rough-rolled sheet; Step 6: Softening Annealing: The rough-rolled sheet is milled and then held at 400℃~630℃ for 2h~6h for softening annealing to allow the sheet to recrystallize completely, thereby improving the sheet's high-temperature resistance and tensile strength. Step 7: Finish rolling: The sheet metal is cold rolled to obtain a finish rolled sheet metal. Before cold rolling, the sheet metal is milled. In order to prevent cracking during the rolling process, the cold rolling adopts a multi-pass rolling process. Step 8: Stress-relief annealing: The precision-rolled plate is milled and then held at 300℃~450℃ for 1h~3h to relieve stress, thus obtaining a high-strength, high-conductivity copper alloy (plate).
[0038] The preferred melting temperature in step two is 1100℃~1500℃.
[0039] The preferred temperature for high-temperature solid solution in step four is 800℃~850℃, and the holding time is 1 hour.
[0040] In step four, the single-pass processing rate of hot rolling is preferably 15% to 20%, the total deformation is preferably 70% to 90%, and the thickness of the obtained hot-rolled plate is preferably 1.2 mm to 3.5 mm.
[0041] The preferred termination temperature for hot rolling in step four is 650℃~700℃.
[0042] In step five, it is preferable to first mill the surface of the hot-rolled sheet and then cold-roll it. In order to prevent cracking during the rolling process, it is preferable to use multi-pass rolling for cold rolling. The single deformation amount of cold rolling is preferably 2% to 5%, the total deformation amount is preferably 45% to 75%, and the thickness of the obtained rough-rolled sheet is preferably 1.0 mm to 2.5 mm.
[0043] In step six, the preferred softening annealing temperature is 450°C, and the preferred holding time is 6 hours.
[0044] In step seven, the single deformation amount of cold rolling is preferably 2% to 5%, the total deformation amount is preferably 75% to 90%, and the thickness of the resulting precision-rolled plate is preferably 0.2 mm to 0.4 mm.
[0045] In step eight, the preferred temperature for stress-relief annealing is 300°C, and the preferred holding time is 1 hour.
[0046] Steps three through five can be replaced by continuous casting and rolling processes.
[0047] This invention also discloses a high-strength, high-conductivity copper alloy based on microalloy solid solution strengthening, which is prepared using any of the preparation methods for high-strength, high-conductivity copper alloys based on microalloy solid solution strengthening disclosed in this invention. The alloy grains of the high-strength, high-conductivity copper alloy based on microalloy solid solution strengthening are equiaxed.
[0048] The following are examples of methods for preparing high-strength, high-conductivity copper alloys based on microalloy solid solution strengthening: Example 1: Step 1: Ingredients: Prepare the raw materials according to the following proportions: Zn by mass 0.3%, Mg by mass 0.35%, Ti by mass 0.06%, and the balance is Cu.
[0049] Step 2: Smelting: The prepared raw materials are smelted in a medium-frequency induction furnace. Charcoal is used for covering during smelting, a molybdenum crucible is used, and cryolite is used as a flux. The smelting temperature is 1300℃. First, pure Cu is melted, then Ti is added, and the mixture is kept at a certain temperature and stirred. After Cu and Ti are fully fused and homogeneous, Mg and Zn are added and stirred to make the mixture homogeneous. Cryolite is added, stirred, and slag is removed. The mixture is kept at a certain temperature for a period of time before being taken out of the furnace (stirring is required during the holding process).
[0050] Step 3: Casting: Using a graphite mold, the mold is dried and dehydrated in an electric furnace before casting. Then, a layer of zinc oxide is coated on the inner wall of the mold. The molten alloy is poured into the mold and air-cooled. After complete cooling, the alloy casting is obtained.
[0051] Step 4: Hot rolling: Before hot rolling, the casting is milled and then heat-treated at 800℃ for 2 hours for high-temperature solution treatment. Then, hot rolling is carried out. The deformation amount of a single hot rolling is 15%. After multiple rolling passes, the total deformation amount is 90%. The final rolling temperature is 650℃. After water quenching, hot-rolled plate is obtained.
[0052] Step 5: Rough rolling: Before rough rolling, the plate is milled to remove the surface oxides. Then, the hot-rolled plate is cold-rolled. The single deformation of cold rolling is 3%, and the total deformation is 60%. After multiple rolling passes, a rough-rolled plate with a thickness of 1.2mm is obtained.
[0053] Step 6: Softening Annealing: The rough-rolled plate is milled and then softened and annealed at 450℃ for 6 hours to allow the grains to recrystallize.
[0054] Step 7: Finish rolling: Before finish rolling, the plate is milled to remove the surface oxides. Then, the plate is cold rolled. The single deformation of cold rolling is 2%, and the total deformation is 75%. After multiple rolling passes, a finish rolled plate with a thickness of 0.3 mm is obtained.
[0055] Step 8: Stress-relief annealing: The precision-rolled sheet is milled and then held at 300℃ for 1 hour to relieve stress, resulting in a high-strength, high-conductivity copper alloy sheet.
[0056] The performance data comparison of each preparation stage in Example 1 is shown in Table 1.
[0057] Table 1. Comparison of performance data at each preparation stage in Example 1
[0058] Table 2 shows the hardness comparison of the softened annealed process sheet of Example 1 under different deformation amounts.
[0059] Table 2. Comparison of hardness of the softened annealed sheet material under different deformation amounts in Example 1
[0060] Table 3 shows the hardness comparison of different stress-relief annealing times in Example 1.
[0061] Table 3. Hardness Comparison under Different Stress-Relief Annealing Times in the Examples
[0062] According to Table 1, the alloy has a hardness of 96 HV and an electrical conductivity of 54% IACS in the as-cast state; a hardness of 110 HV and an electrical conductivity of 50% IACS after hot rolling (CR1 (2.5)); a hardness of 144 HV and an electrical conductivity of 47% IACS after rough rolling (CR2 (1.2)); a hardness of 140 HV and an electrical conductivity of 62% IACS after softening annealing (450℃ / 6h); a hardness of 176 HV and an electrical conductivity of 52% IACS after finish rolling (CR3 (0.3)); and a hardness of 165 HV and an electrical conductivity of 60% IACS after stress-relief annealing (300℃ / 1h). See also... Figure 3 The stress-strain strength of the sheet metal after softening annealing (450℃ / 6h) is 418MPa, the elongation is 20%, and the conductivity is 62%IACS; the stress-strain strength of the sheet metal after finishing rolling (CR3 (0.3)) is 615MPa, the elongation is 20%, and the conductivity is 52%IACS.
[0063] Combination Figure 2 As shown in Table 2, copper alloys exhibit good hardness when the deformation amount is 75%. From... Figure 3 It can be seen that the best tensile strength of the plate after precision rolling (CR3(0.3)) is 615 MPa. Due to the lack of stress-relief annealing, the elongation is low at 3%. The elongation of the plate after softening annealing (450℃ / 6h) reaches 23%, and the tensile strength is 418 MPa. According to Table 3, the hardness of copper alloy is optimal when the stress-relief annealing time is 0.75h~1h.
[0064] Figure 4In the figures, (a) to (d) are metallographic images after softening annealing (450℃ / 6h) in Example 1, with scale bars of 200μm, 100μm, 50μm, and 20μm, respectively. (i) to (l) are EDS images after softening annealing (450℃ / 6h) in Example 1. After recovery and recrystallization, the fibrous structure is transformed into equiaxed grains, and the high-density dislocations introduced by cold rolling (rough rolling) are basically eliminated, resulting in a significant increase in conductivity. At the same time, fine grain strengthening and solid solution strengthening compensate for the strength loss caused by the disappearance of dislocations. Ultimately, the aged alloy maintains high strength while achieving a significant leap in conductivity, exhibiting excellent synergistic performance of tensile strength and conductivity. Images (e) to (h) are metallographic images of the alloy after precision rolling in Example 1, with scale bars of 200 μm, 100 μm, 50 μm, and 20 μm, respectively. The microstructure exhibits a typical fibrous, highly deformable structure. High-density dislocations and entangled grain boundaries create a strong work hardening effect, imparting extremely high tensile strength to the alloy. However, lattice distortion and the synergistic effect of high-density dislocations (i.e., solid-solution solute atoms) lead to intensified electron scattering, resulting in a relatively low conductivity. Subsequent stress-relief annealing restored the conductivity while preserving most of the hardness.
[0065] Example 2: Step 1: Ingredients: Prepare the raw materials according to the following proportions: Zn by mass 0.2%, Mg by mass 0.3%, Ti by mass 0.1%, and the balance is Cu.
[0066] Step 2: Smelting: The prepared raw materials are smelted in a medium-frequency induction furnace. Charcoal is used for covering during smelting, a molybdenum crucible is used, and cryolite is used as a flux. The smelting temperature is 1100℃. First, pure Cu is melted, then Ti is added, and the mixture is kept at a certain temperature and stirred. After Cu and Ti are fully fused and homogeneous, Mg and Zn are added and stirred to make the mixture homogeneous. Cryolite is added, stirred, and slag is removed. The mixture is kept at a certain temperature for a period of time before being taken out of the furnace (stirring is required during the holding process).
[0067] Step 3: Casting: Using a graphite mold, the mold is dried and dehydrated in an electric furnace before casting. Then, a layer of zinc oxide is coated on the inner wall of the mold. The molten alloy is poured into the mold and air-cooled. After complete cooling, the alloy casting is obtained.
[0068] Step 4: Hot rolling: Before hot rolling, the casting is milled and then heat-treated at 800℃ for 1 hour for high-temperature solution treatment. Then, hot rolling is carried out. The single deformation of hot rolling is 20%. After multiple rolling passes, the total deformation is 80%. The final rolling temperature is 700℃. After water quenching, hot-rolled plate is obtained.
[0069] Step 5: Rough rolling: Before rough rolling, the plate is milled to remove the surface oxides. Then, the hot-rolled plate is cold-rolled. The single deformation of cold rolling is 4%, and the total deformation is 50%. After multiple rolling passes, a rough-rolled plate with a thickness of 1.2mm is obtained.
[0070] Step 6: Softening Annealing: The rough-rolled plate is milled and then softened and annealed at 500℃ for 4 hours to allow the grains to recrystallize.
[0071] Step 7: Finish rolling: Before finish rolling, the plate is milled to remove the surface oxides. Then, the plate is cold rolled. The single deformation of cold rolling is 3%, and the total deformation is 80%. After multiple rolling passes, a finish rolled plate with a thickness of 0.3 mm is obtained.
[0072] Step 8: Stress-relief annealing: The precision-rolled sheet is milled and then held at 450℃ for 2 hours to relieve stress, resulting in a high-strength, high-conductivity copper alloy sheet.
[0073] Example 3: Step 1: Ingredients: Prepare the raw materials according to the following proportions: Zn by mass 0.3%, Mg by mass 0.4%, Ti by mass 0.05%, and the balance is Cu.
[0074] Step 2: Smelting: The prepared raw materials are smelted in a medium-frequency induction furnace. Charcoal is used for covering during smelting, a molybdenum crucible is used, and cryolite is used as a flux. The smelting temperature is 1500℃. First, pure Cu is melted, then Ti is added, and the mixture is kept at a certain temperature and stirred. After Cu and Ti are fully and uniformly fused, Mg and Zn are added and stirred to make the fusion uniform. Cryolite is added, stirred, and slag is removed. The mixture is kept at a certain temperature for a period of time before being taken out of the furnace (stirring is required during the holding process).
[0075] Step 3: Casting: Using a graphite mold, the mold is dried and dehydrated in an electric furnace before casting. Then, a layer of zinc oxide is coated on the inner wall of the mold. The molten alloy is poured into the mold and air-cooled. After complete cooling, the alloy casting is obtained.
[0076] Step 4: Hot rolling: Before hot rolling, the casting is milled and then heat-treated at 850℃ for 1 hour for high-temperature solution treatment. Then, hot rolling is carried out. The single deformation of hot rolling is 17%. After multiple rolling passes, the total deformation is 70%. The final rolling temperature is 680℃. After water quenching, hot-rolled plate is obtained.
[0077] Step 5: Rough rolling: Before rough rolling, the plate is milled to remove the surface oxides. Then, the hot-rolled plate is cold-rolled. The single deformation of cold rolling is 5%, and the total deformation is 70%. After multiple rolling passes, a rough-rolled plate with a thickness of 2.5mm is obtained.
[0078] Step 6: Softening Annealing: The rough-rolled plate is milled and then held at 630℃ for 2 hours for softening annealing to allow the grains to recrystallize.
[0079] Step 7: Finish rolling: Before finish rolling, the plate is milled to remove the surface oxides. Then, the plate is cold rolled. The single deformation of cold rolling is 5%, and the total deformation is 88%. After multiple rolling passes, a finish rolled plate with a thickness of 0.2 mm is obtained.
[0080] Step 8: Stress-relief annealing: The precision-rolled sheet is milled and then held at 420℃ for 3 hours to relieve stress, resulting in a high-strength, high-conductivity copper alloy sheet.
[0081] Example 4: Step 1: Ingredients: Prepare the raw materials according to the following proportions: Zn by mass 0.4%, Mg by mass 0.2%, Ti by mass 0.08%, and the balance is Cu.
[0082] Step 2: Smelting: The prepared raw materials are smelted in a medium-frequency induction furnace. Charcoal is used for covering during smelting, a molybdenum crucible is used, and cryolite is used as a flux. The smelting temperature is 1500℃. First, pure Cu is melted, then Ti is added, and the mixture is kept at a certain temperature and stirred. After Cu and Ti are fully and uniformly fused, Mg and Zn are added and stirred to make the fusion uniform. Cryolite is added, stirred, and slag is removed. The mixture is kept at a certain temperature for a period of time before being taken out of the furnace (stirring is required during the holding process).
[0083] Step 3: Continuous casting and rolling: The alloy is cast into the tundish, and a covering agent is added to keep it warm and isolate it from the air. The internal temperature is maintained at about 1050℃. Then it is distributed to the crystallizer to cool and obtain the billet. The billet is then sent to the continuous rolling mill for rolling. After the continuous rolling is completed, it is water-cooled to obtain the continuously cast and rolled plate.
[0084] Step 4: Annealing: Anneal the continuously cast and rolled plates by holding them at 400℃ for 6 hours to obtain copper alloy plates with matching strength and toughness.
[0085] Step 5: Finish rolling: Before finish rolling, the plate is milled to remove the surface oxides. Then, the plate is cold rolled. The single deformation of cold rolling is 5%, and the total deformation is 85%. After multiple rolling passes, a finish rolled plate with a thickness of 0.3 mm is obtained.
[0086] Step 8: Stress-relief annealing: The precision-rolled sheet is milled and then held at 300℃ for 1 hour to relieve stress, resulting in a high-strength, high-conductivity copper alloy sheet.
[0087] This invention, through the rational selection of alloy composition and further control of heat treatment process, successfully prepared a copper alloy with high strength, high elongation, and high conductivity while achieving micro-scale multi-component synergistic alloying and low-damage solid solution strengthening. After annealing, the alloy undergoes complete recrystallization, transforming the fibrous structure into equiaxed crystals. The disappearance of high-density dislocations significantly improves conductivity. Fine-grain strengthening and solid solution strengthening allow it to maintain high strength. The prepared copper alloy has an ultimate tensile strength of 580 MPa to 620 MPa, an elongation of 2% to 4%, a hardness of 160 HV to 170 HV, and a conductivity of 60% IACS to 62% IACS.
Claims
1. A method for preparing high-strength, high-conductivity copper alloys based on microalloy solid solution strengthening, characterized in that... Includes the following steps: Step 1: Prepare the raw materials for the copper alloy. The raw materials, by mass percentage, include 0.2%~0.4% Zn, 0.2%~0.4% Mg, 0.05%~0.1% Ti, and the balance is Cu. Step 2: Melt the prepared raw materials. After melting pure Cu, first add Ti, stir and melt evenly, then add Mg and Zn, stir and melt evenly again, then add cryolite, stir and skim off the slag, keep warm for a period of time and then remove from the furnace. Step 3: Pour the molten alloy into a mold and air cool it. After it has completely cooled, you will get a cast copper alloy part. Step 4: The casting is subjected to high-temperature solution treatment, then hot-rolled, and water-quenched to obtain hot-rolled sheet metal; Step 5: Cold roll the hot-rolled sheet to obtain a rough-rolled sheet; Step Six: Soften and anneal the rough-rolled sheet to allow it to fully recrystallize; Step 7: Cold roll the sheet material to obtain a precision-rolled sheet material; Step 8: Stress-relief annealing is performed on the precision-rolled sheet to obtain a high-strength, high-conductivity copper alloy.
2. The method for preparing high-strength, high-conductivity copper alloy based on microalloy solid solution strengthening according to claim 1, characterized in that... The softening annealing temperature in step six is 400℃~630℃, and the holding time is 2h~6h.
3. The method for preparing high-strength, high-conductivity copper alloy based on microalloy solid solution strengthening according to claim 2, characterized in that... The softening annealing temperature is 450℃, and the holding time is 6 hours.
4. The method for preparing high-strength, high-conductivity copper alloy based on microalloy solid solution strengthening according to claim 1, characterized in that... The stress-relief annealing temperature in step eight is 300℃~450℃, and the holding time is 1h~3h.
5. The method for preparing high-strength, high-conductivity copper alloy based on microalloy solid solution strengthening according to claim 3, characterized in that... The stress-relief annealing temperature is 300℃, and the holding time is 1 hour.
6. The method for preparing a high-strength, high-conductivity copper alloy based on microalloy solid solution strengthening according to claim 1, characterized in that... The melting temperature in step two is 1100℃~1500℃.
7. The method for preparing a high-strength, high-conductivity copper alloy based on microalloy solid solution strengthening according to claim 1, characterized in that... The high-temperature solution treatment in step four is carried out at a temperature of 800℃~850℃ for 1 hour.
8. The method for preparing high-strength, high-conductivity copper alloy based on microalloy solid solution strengthening according to claim 1, characterized in that... The termination temperature of hot rolling in step four is 650℃~700℃.
9. A high-strength, high-conductivity copper alloy based on microalloy solid solution strengthening, characterized in that... The high-strength, high-conductivity copper alloy based on microalloy solid solution strengthening is prepared by any one of claims 1-8.
10. The high-strength, high-conductivity copper alloy based on microalloy solid solution strengthening according to claim 9, characterized in that... The alloy grains are equiaxed.