Copper alloy material having high strength and high electrical conductivity and method for manufacturing the same

Abstract

This invention provides a copper alloy material with high strength and high electrical conductivity, and a method for manufacturing the same. [Solution] The copper alloy material contains, by mass percentage, 0.4 wt% to 1.5 wt% Cr, 0.6 wt% to 1.5 wt% Hf, 0 to 0.02 wt% P, 0 to 0.15 wt% Ce, 0 to 0.2 wt% Zn, 0 to 0.2 wt% Ag, with the remainder being Cu.

Description

Technical Field

[0001] The present invention belongs to the technical field of copper alloy processing, and specifically relates to a copper alloy material having high strength and high electrical conductivity and a manufacturing method thereof.

Background Art

[0002] Copper alloys are widely used in fields such as energy and power, electronics and electrical equipment, transportation, and marine engineering as functional structural materials with high strength, excellent electrical and thermal conductivity, and good wear and corrosion resistance. With the rapid development of high-tech industries such as 5G electronic communication, new energy vehicles, very large scale integrated circuits, and high-speed railway transportation, the demand for copper alloys, especially copper alloys with special properties such as high strength and high electrical conductivity, is increasing rapidly, and the high requirements for the comprehensive performance of copper alloy materials are also increasing. Copper alloys are required to have excellent softening resistance and be usable even in a harsh high-temperature environment on the premise of ensuring the comprehensive performance of high strength and high electrical conductivity.

[0003] Conventional copper alloys having high strength and high electrical conductivity usually improve the mechanical properties of the copper alloy by sacrificing part of the electrical conductivity. When a large amount of elements are introduced into the copper alloy, the base material can be strengthened by solid solution strengthening, but the solid solution elements greatly disrupt the periodic potential field of the metal crystal and significantly reduce the electrical conductivity of the alloy. When elements that can precipitate as a single substance or an intermetallic compound are added synergistically and composite deformation heat treatment means such as deformation and aging are adopted, the added elements can be promoted to precipitate from the base material as strengthening phases, purify the base material to a certain extent, and realize the simultaneous improvement of electrical conductivity and mechanical properties. However, this method has limitations and is subject to the constraint of solubility, and the achievable purification effect and strengthening effect cannot be improved infinitely.

[0004] Cu-Zn, Cu-Mg, and Cu-Zr alloys, developed in the early stages of copper alloy development for high strength and high electrical conductivity, primarily rely on solid solution strengthening as their strengthening mechanism, and have not reached satisfactory levels of strength or electrical conductivity. Currently, precipitation-strengthened Cu-Fe-P, Cu-Ni-Si, and Cu-Cr alloys, which are more widely used, have achieved generational progress in overall performance, but they also have certain drawbacks, and each has its own performance limitations. High mass percentage Si added to Cu-Ni-Si alloys provides sufficient deposition driving force for Ni2Si, but Si atoms remaining in the copper matrix significantly degrade the electrical conductivity of the alloy, making it difficult to exceed 50% IACS (International Annealed Copper Standard). In Cu-Fe-P alloys, the strengthening effect of the Fe element on the alloy is limited, and with small amounts of Fe added, electrical conductivity reaches 90% IACS, but the strength is only 450 MPa. On the other hand, increasing the amount of additive can improve strength at the expense of some electrical conductivity, but this is usually not worthwhile, and it is difficult to exceed a tensile strength of 600 MPa, while at the same time, the electrical conductivity also drops to below 80% IACS. In Cu-Cr alloys, the Cr phase that precipitates becomes significantly coarser with increasing aging time and aging temperature, and its contribution to the mechanical properties of the alloy decreases significantly, making it difficult to exceed a tensile strength of 630 MPa.

[0005] The tensile strength of Cu-Fe-P and Cu-Cr alloys can be surpassed under certain extreme deformation conditions (such as deep cooling and intense plastic deformation), reaching levels difficult to achieve with conventional deformation methods and enabling superior overall performance. However, performance improvements achieved through extreme deformation conditions come at the expense of the potential for large-scale industrialized production. How to simultaneously achieve high strength and high electrical conductivity to obtain high-performance copper alloys with good overall performance has always been a hot spot and challenge in research, and also an indicator of the technological level of the high-performance copper processing industry. Therefore, there is a need to develop new high-performance copper alloy systems that meet the high-performance demands of modern and high-tech industries. [Overview of the project]

[0006] To overcome the shortcomings of related technologies, the first objective of this application is to provide a copper alloy material with high strength and high electrical conductivity. The copper alloy material provided in this application employs a different strengthening concept than conventional copper alloys with high strength and high electrical conductivity. By adjusting the types and amounts of alloying elements, the types of major nanoscale strengthening phases of the alloy are increased, while simultaneously ensuring the large-scale precipitation of the added elements. Assuming that the electrical conductivity of the copper alloy does not deteriorate rapidly, the mechanical performance of the alloy is greatly improved, thereby enabling the alloy to exhibit superior overall performance.

[0007] The second object of this application is to provide a method for manufacturing copper alloy materials having high strength and high electrical conductivity. Compared to conventional general manufacturing methods, the manufacturing method provided by this application improves the overall performance of the alloy while being simple and controllable, suitable for the specific conditions of industrial production, and suitable for large-scale industrial production. The manufacturing method of this application makes it possible to produce alloys with finer crystal grains, strengthening the contribution of the fine-grain strengthening mechanism to the alloy's mechanical performance, while simultaneously providing sufficient precipitation driving force and promoting broad precipitation of the precipitated phase. Therefore, the alloy can obtain superior overall performance, and the improvement in overall performance is not selective due to differences in the composition of precipitation-strengthened copper alloys having high strength and high electrical conductivity, but has a broad strengthening effect. In addition, the manufacturing method provided by this application has an additional microstructure control effect on the multi-nanoscale strengthened phase copper alloy material provided by this application, and can control the precipitation order of the precipitated phase.

[0008] To achieve the aforementioned objective, this application employs the following technical solutions.

[0009] This application provides a copper alloy material having high strength and high electrical conductivity. The copper alloy material has the following composition by mass percentage. It contains 0.4 wt% to 1.5 wt% Cr, 0.6 wt% to 1.5 wt% Hf, 0 to 0.02 wt% P, 0 to 0.15 wt% Ce, 0 to 0.2 wt% Zn, and 0 to 0.2 wt% Ag, with the remainder being Cu.

[0010] The copper alloy material provided in this application is a CuCrHf alloy material, and both Cr and Hf in the CuCrHf alloy are major added elements. This is the fundamental reason why the copper alloy material with high strength and high electrical conductivity of this application is superior to conventional copper alloys. The compositional design of conventional copper alloys with high strength and high electrical conductivity has centered on one nanoscale strengthening phase, and other elements have been selected based on the strengthening concept of promoting precipitation or modifying the precipitated phase. For example, taking copper alloy materials containing Hf as an example, since the intrinsic solid solubility of the element Hf in the Cu matrix is ​​finite, the current mainstream method of using the element Hf is to add it in small amounts as a solid solution strengthening element in other alloy systems, and the strengthening effect on the alloy is limited.

[0011] On the other hand, the CuCrHf alloy provided in this application increases the variety of high-density nanoscale reinforcing phases (Cr phase and CuHf phase) in the alloy by simultaneously adding high-content Cr and high-content Hf elements. Therefore, compared to conventional copper alloys with high strength and high electrical conductivity that use a single nanoscale precipitate phase as the reinforcing phase, it has greater precipitation potential and space for strength improvement (Fe phase in Cu-Fe-P alloy, Ni2Si phase in Cu-Ni-Si alloy, Cr phase in Cu-Cr alloy). It should be particularly noted that despite the high amounts of Cr and Hf elements added, the CuCrHf alloy does not suffer from insufficient improvement in electrical conductivity like the Cu-Ni-Si alloy. This is because the room-temperature solid solubility of Cr and Hf elements in copper is close to zero, and after composite deformation heat treatment, both Cr and Hf elements can be sufficiently desoluble from the base material as precipitate phases, guaranteeing that the alloy has high electrical conductivity. The addition of Hf element also has the effect of lowering the stacking fault energy of the alloy, causing the alloy to form deformation twins during the normal cold rolling deformation process, inhibiting the interaction between dislocations, and retaining a higher dislocation density and more substructures in the alloy matrix, improving the recrystallization temperature and softening resistance of the alloy, and effectively improving the work hardening rate and final mechanical performance of the alloy.

[0012] Furthermore, this invention also includes trace amounts of additive elements P, Ce, Zn, and Ag. On the one hand, these can control the quality of the molten product or refine the crystal grains. For example, element P purifies the base material, improves the fluidity of the molten copper alloy, and enhances the casting quality of the ingot. Element Ce can refine the crystal grains. Trace amounts of elements Ag and Zn have very little effect on the electrical conductivity of the alloy, and solid solution strengthening can be achieved in the base material, provided that the electrical conductivity is slightly reduced. On the other hand, these trace elements can effectively adjust the morphology of the precipitated phases, causing the CuHf and Cr phases to be more finely and uniformly dispersed in the base material as spherical phases, thereby improving the overall performance of the alloy.

[0013] Due to the synergistic effect of the above-mentioned components and their content, the alloy of this invention possesses excellent overall performance, including high hardness, high strength, high electrical conductivity, and high softening temperature resistance.

[0014] The elemental content of the alloy in this application must be controlled within the specified range, thereby enabling effective synergistic effects. If the amount of Cr is too low, it will not provide sufficient precipitation driving force, making it difficult to achieve sufficient strengthening and base material purification effects, and the performance indicators of the final alloy product will decrease significantly. If the amount of Cr is too high, a coarse primary phase rich in Cr will appear in the base material. As the degree of excess increases, the quantity and size of this Cr phase will increase, and its effect on improving the strength of the material will be extremely limited, which is also detrimental to subsequent manufacturing processes and grain refinement. Similarly, if the amount of Hf is too low, it will not provide sufficient precipitation driving force. Although the added Hf can exert a certain solid solution strengthening effect in the base material, the slight improvement in strength is far less significant than the decrease in electrical conductivity compared to the increased electron scattering effect. On the other hand, if there is an excess of Hf, the quantity and size of coarse, Hf-rich primary phases in the matrix also increase, and in severe cases, it may even be possible to form CuHf amorphous material, which is detrimental to the overall performance of the material. P, Ce, Ag, and Zn are trace elements of the high-strength and high-electrically conductive copper alloy provided by this application. They can improve the quality of the molten product and adjust the structure of the alloy, and are of great importance to the overall performance of the alloy, but the amount added should not be too much. In particular, if the content of P, Ce, and Zn is too high, it will drastically reduce the electrical conductivity of the alloy, not only failing to provide a significant strengthening effect but also degrading the overall performance of the alloy. If the content is too low, the effect of the addition will not be obtained. By adjusting the amount of elemental addition within the scope of this application, it is possible to avoid a large impact on electrical conductivity, or to avoid desolving from the matrix and solid-solving in the Cu matrix, and to increase the electron scattering effect by the lattice.

[0015] Optionally, the copper alloy material has the following composition by mass percentage: 0.4 wt% to 0.7 wt% Cr, 0.6 wt% to 0.9 wt% Hf, 0 to 0.02 wt% P, 0 to 0.02 wt% Ce, 0 to 0.02 wt% Zn, 0 to 0.2 wt% Ag, with the remainder being Cu.

[0016] Furthermore, optionally, the copper alloy material may have the following composition by mass percentage: 0.7 wt% Cr, 0.9 wt% Hf, 0.02 wt% P, 0.01 wt% Ce, 0.01 wt% Zn, 0.02 wt% Ag, with the remainder being Cu.

[0017] Selectively, in the copper alloy material having high strength and high electrical conductivity, interactions exist between multiple nanoscale precipitated phases and dislocations, which are pinned and entangled with each other and finely and uniformly dispersed in the matrix material, and the crystal grain size of the copper alloy material having high strength and high electrical conductivity is 30 μm or less, and the crystal grains contain twins.

[0018] The copper alloy material provided in this application, possessing high strength and high electrical conductivity, has fine crystal grains and a high number of twins. Interactions exist between multiple high-density nanoscale precipitate phases and high-density dislocations, causing them to pin and entangle with each other. This indicates that the nanoscale precipitate phase particles effectively pin the movement of dislocations, improving the strength and toughness of the alloy.

[0019] This invention further provides a method for manufacturing a copper alloy material having high strength and high electrical conductivity. First, each raw material is blended according to the ratio of the component design, melted to obtain an alloy solution, and the alloy solution is cast to obtain a copper alloy ingot. Next, the copper alloy ingot is subjected to homogenization annealing, hot deformation treatment, and solid solution treatment in sequence to obtain a solid solution alloy material. Finally, the solid solution alloy material is subjected to pre-aging treatment, pre-cold deformation treatment, regression treatment, and composite deformation heat treatment in sequence to obtain a copper alloy material having high strength and high electrical conductivity.

[0020] In the manufacturing method of this invention, first, melting is performed in an atmospheric atmosphere using a medium-frequency melting furnace, and the molten metal is cast and molded to complete the production of a copper alloy ingot. Next, the copper alloy ingot is subjected to conventional microstructure control, including homogenization annealing, hot deformation, and solid solution treatment. Upon completion of these treatments, most defects in the casting are removed, and all elements added within the scope of this invention are dissolved in the copper alloy base material. The purpose of the homogenization annealing treatment is to remove as much segregation as possible that has occurred inside the crystal grains of the casting during the melting and casting process. The hot deformation treatment is to further remove casting defects in the casting, and the solid solution treatment is to effectively form solid solutions between trace elements and the copper base material. Finally, by performing pre-aging treatment, pre-cold deformation treatment, regression treatment, and composite deformation heat treatment on the alloy after solid solution is completed, an alloy sample with superior performance can be produced. The aforementioned alloy processing process is the core of this manufacturing method. The precipitation-strengthened phase generated during the aging process increases the strengthening effect of dislocations generated during the cold deformation process, thereby rapidly inducing widespread recovery recrystallization during the regression process and enabling the production of a pre-aged sample with finer grains. Subsequently, the alloy can be subjected to a conventional composite deformation heat treatment. This composite deformation heat treatment includes multi-pass cold rolling and aging, precipitation of alloying elements dissolved in the lattice as much as possible, intensifying dislocation proliferation during the deformation process, and improving the values ​​of precipitation strengthening and deformation strengthening.

[0021] In this application, it is extremely important to perform pre-aging treatment, pre-cold deformation treatment, and regression treatment before the composite deformation heat treatment. When the alloy material after solid solution treatment is directly subjected to composite deformation treatment, the base material obtains a large amount of CuHf phase, but the CuHf phase precipitates in multiple forms (rod-shaped, spherical, disc-shaped), grows and coarses during the aging process, and the strengthening effect on the base material is greatly weakened. On the other hand, the inventors have found that the regression process not only refines the crystal grains, but also controls the precipitation order by interrupting the CuHf phase precipitation process, thereby maximizing the strengthening effect provided by the nanoscale CuHf phase, and finally, through the synergistic effect with the tracely added elements in this application, both the CuHf phase and the Cr phase are dispersed more finely and uniformly in the base material as nanospherical phases, thereby achieving a superior strengthening effect.

[0022] According to the above manufacturing method, the high-density nanoscale Cr phase and CuHf phase are finely and uniformly dispersed in the matrix as the main strengthening second phase of the alloy, intertwining with fine crystal grains and high-density dislocations to form a microstructure characteristic of multi-mechanism synergistic strengthening. This imparts excellent mechanical properties, electrical conductivity, and softening resistance to the manufactured CuCrHf alloy. On the other hand, through the aging, cold deformation, and regression processes, some solid solution elements are first desoluble from the matrix, becoming sources of dislocation proliferation in the subsequent deformation process and nucleation sites and grain boundary pinning points in the regression process. This increases the density of dislocations introduced into the matrix by cold deformation, reduces the size of recrystallized grains, and the initial crystal grain size of the alloy is significantly superior to that of an untreated solid solution alloy. On the other hand, the Cr and Hf elements dissolved in the base material desolve from the copper alloy solid solution through cold deformation and heat treatment, and become uniformly and finely dispersed in the base material. Combined with the solid solution strengthening effect of trace amounts of Ag and Zn elements on the base material, the alloy exhibits excellent electrical conductivity, as well as excellent mechanical properties and softening resistance.

[0023] The melting process is optionally carried out as follows: Pure copper, Cu-Cr intermediate alloy, Cu-Hf intermediate alloy, Cu-Zn intermediate alloy, Cu-P intermediate alloy, pure Ce, pure Ag, and pure Zn are blended according to the design ratio. First, the pure copper is melted, and the temperature is further increased to 1200°C to 1300°C. Pure Ag and pure Zn are added, and the temperature is further increased to 1300°C to 1400°C. The Cu-Cr intermediate alloy is added in 3 to 4 portions, and after holding the temperature for 2 to 3 minutes, it is stirred for 30 to 60 seconds. Then, the Cu-Hf intermediate alloy, pure Ce, and Cu-P intermediate alloy are added, and after holding the temperature for 1 to 2 minutes, it is cooled to 1200°C to 1300°C while stirring.

[0024] In this application, since there are relatively many alloy elements, by adopting the above-mentioned optional form of raw material charging order, the burning loss of alloy elements can be effectively reduced. Furthermore, since there are relatively many alloy elements to be added, the viscosity of the molten metal is high during the melting process and floating slag is also likely to be generated. However, the Cu-P master alloy to be added can be effectively alleviated by combining with the stirring operation after step-by-step addition, purify the molten metal, improve the fluidity of the molten metal, and thus improve the quality of the ingot. Stirring during the melting process, on the one hand, promotes the sufficient melting of the alloy elements added step by step, makes the components uniform everywhere in the molten metal, and on the other hand, can also alleviate the cooling effect of the local molten metal due to step-by-step addition.

[0025] In the actual operation process, melting is carried out in an air atmosphere using an intermediate frequency induction furnace, and stirring is carried out using a graphite rod during the melting process.

[0026] Optionally, the melting is carried out in an air atmosphere, and during the melting process, the molten metal is covered with graphite. By covering the molten metal with graphite as a deoxidizer, the burning loss rate can be reduced.

[0027] Optionally, the temperature of the casting molding is 1200°C to 1450°C, and the preheating temperature of the mold is 400°C to 500°C.

[0028] Optionally, the temperature of the homogenization annealing treatment is 780°C to 980°C, and the time of the homogenization annealing treatment is 2h to 8h. The purpose of the homogenization annealing treatment is to remove the segregation phenomenon in the casting structure and remove the non-uniformity of the fine structure as much as possible. The effect of the homogenization annealing treatment depends on the selected conditions. If the temperature is too high, the alloy is likely to overheat and even melt, and the quality of the cast alloy may not improve but rather decrease. If the temperature is too low, the diffusion of elements is difficult, and it is difficult to completely remove the segregation within the crystal even by extending the holding time of the homogenization annealing treatment. Also, if the homogenization time is too long, the manufacturing flow and process cost will increase.

[0029] Optionally, the hot deformation treatment is selected from hot forging or hot rolling. The temperature of the hot deformation treatment is 850°C to 950°C, the total deformation amount is 50% to 90%, and the deformation amount per pass is 10% to 20%.

[0030] In actual operation, after the homogenization heat treatment is completed, the ingot after the homogenization annealing treatment is cooled in the furnace to the temperature required for hot deformation, and then hot deformation can be carried out. Through the hot deformation treatment, the casting defects of the alloy are removed as much as possible, the dynamic recrystallization of the alloy is promoted, and the coarse crystal grains after melting, casting and homogenization heat treatment are refined.

[0031] Optionally, the temperature of the solution treatment is 800°C to 1050°C, the time of the solution treatment is 2h to 8h, and after the solution treatment is completed, water quenching is carried out.

[0032] Through the solution treatment, all the added alloying elements are dissolved into the copper alloy base material. Through water quenching, the supersaturated solid solution state is maintained to room temperature, providing sufficient precipitation driving force.

[0033] Optionally, the temperature of the pre-aging is 350°C to 600°C, and the time of the pre-aging is 5min to 480min.

[0034] After the solution treatment is completed, the alloy already has sufficient precipitation driving force. After aging, a considerable amount of nanoscale CuHf phase and Cr phase have already formed inside the alloy. By combining with subsequent deformation and regression treatment, better precipitation effect and fine grain effect can be obtained. In actual operation, after the aging treatment, it is necessary to remove and correct the defects on the alloy surface by machining.

[0035] Optionally, the total deformation amount of the pre-cold deformation treatment is 40% to 90%, and the deformation amount per pass is in the range of 10% to 30%.

[0036] Optionally, the temperature of the regression treatment is 750°C to 1000°C, and the time of the treatment is 10s to 10min.

[0037] The purpose of the regression treatment is to combine the high-density nanophase precipitated during pre-aging with the high-density dislocations introduced during the pre-cold deformation process, thereby inducing extensive recrystallization in the alloy, refining the grain size, and increasing its contribution to the alloy's strength. It also interrupts the CuHf phase precipitation process, thereby maximizing the strengthening effect provided by the nanoscale CuHf phase. The regression treatment temperature must be within a set range. If the regression temperature is too low, the recrystallization effect will not be obtained, and only the formation of the precipitated phase will be adjusted. On the other hand, if the regression temperature is too high, secondary recrystallization is likely to occur, not only preventing grain refinement but also causing the alloy's structure to revert to the solid solution treatment state.

[0038] Optionally, the composite deformation heat treatment consists of alternating cold deformation and aging treatments. In the actual operation, the amount and number of cold deformation cycles, and the temperature, time, and number of aging cycles are adjustable, and there are certain differences in the performance of alloys produced under different treatment conditions. If both cold deformation and aging are performed once, the amount of cold deformation should be 60% to 90%, and the aging temperature and time should be 350°C to 600°C and 5 min to 480 min.

[0039] Furthermore, optionally, the composite deformation heat treatment consists of two cold deformations and two aging treatments, where the deformation amount of the first cold deformation is 40% to 90% and the pass deformation amount is 10% to 30%. After the first cold deformation treatment, the first aging treatment is performed, followed by a second cold deformation treatment. The deformation amount of the second cold deformation treatment is 40% to 90% and the pass deformation amount is 10% to 30%. After the second cold deformation treatment is completed, a second aging treatment is performed. The temperature of the first aging treatment is 350°C to 600°C, preferably 450°C to 500°C, and the time is 5 min to 480 min, and the temperature of the second aging treatment is 350°C to 600°C, preferably 350°C to 450°C, and the time is 5 min to 480 min.

[0040] After regression treatment, further composite deformation heat treatment is applied, resulting in a large amount of nano-spherical CuHf and Cr phases being finely and uniformly dispersed in the base material. This allows for the production of a copper alloy with superior overall performance, high strength, and high electrical conductivity.

[0041] The positive and beneficial effects obtained by this application are as follows:

[0042] (1) Copper alloy sheets manufactured by completing a series of processes according to the manufacturing process specified in this application have an electrical conductivity of 70%IACS-89%IACS, a hardness of 180HV-230HV, a tensile strength of 670MPa-730MPa, and an elongation of 8.2%-16.7%, significantly improving the strength of the alloy system while possessing excellent alloy plasticity and electrical conductivity. Compared with other high-strength and high-electrical-conductivity copper alloys, the overall mechanical performance of the alloy manufactured in this application is superior, enriching China's product library of high-strength and high-electrical-conductivity copper alloys.

[0043] (2) By shifting the approach to strengthening through precipitation phase modification using alloying elements, and adding Hf elements that form a single-phase solid solution region with Cu and Cr, and controlling the alloy structure in combination with a deformation heat treatment process, a combined strengthening effect of two types of nanoscale strengthening phases is achieved, significantly improving the overall performance of the alloy and achieving a higher combination of strength and electrical conductivity.

[0044] (3) The overall performance of the alloy was improved while maintaining the high electrical conductivity of the alloy as much as possible. The fundamental reason for this is the adjustment of the microstructure by the alloying elements Hf, P, Ce, Zn, and Ag. The addition of Hf, Zn, and Ag has the effect of lowering the stacking fault energy of the alloy, and the alloy forms deformation twins during the normal cold rolling deformation process, improving the strength of the alloy and effectively improving the hardening effect of the alloy in the subsequent deformation process. The element P purifies the molten metal, improves the fluidity of the molten alloy, and improves the quality of the alloy ingot obtained by casting. The element Ce can refine the crystal grains.

[0045] (4) By employing a manufacturing method involving pre-aging, pre-cold deformation, regression process, and combined deformation heat treatment, the precipitation potential of the alloy can be maximized. The pinning effect of the precipitated phase on dislocations, formed during the first aging process, is utilized and combined with subsequent cold deformation to introduce a large number of dislocations into the base material, thereby improving the mechanical properties of the alloy through deformation strengthening, precipitation strengthening, and some solid solution strengthening. More importantly, the above process is used to control the precipitation order of the CuHf phase, ultimately resulting in the precipitation of a large amount of nanospherical CuHf and Cr phases, which are finely and uniformly dispersed in the base material. This yields a copper alloy with the best overall performance, high strength, and high electrical conductivity.

[0046] Details of one or more embodiments of the present application are disclosed in the following drawings and description. Other features, purposes, and advantages of the present application will become apparent from the specification, drawings, and claims. [Brief explanation of the drawing]

[0047] To more clearly illustrate the embodiments of this application or the technical solutions in the prior art, the drawings necessary for describing the embodiments or the prior art are briefly described below. Clearly, the drawings described below are merely embodiments of this application, and those skilled in the art can obtain other drawings without creative effort based on the disclosed drawings. [Figure 1] This invention relates to a novel manufacturing process flow for a copper alloy material having high strength and high electrical conductivity. [Figure 2] This shows the EBSD results after solid solution treatment of the copper alloy in Example 1 of the present application. [Figure 3] These are the EBSD results of the copper alloy sample after regression treatment in Example 1 of the present invention. [Figure 4] This is the curve showing the change in hardness against aging temperature and time after regression treatment of the copper alloy in Example 1 of the present invention and subsequent 80% deformation. [Figure 5]This is the curve showing the change in hardness against aging temperature and time when a copper alloy in Example 1 of the present invention is subjected to regression treatment, 80% deformation at 450°C for 2 hours, and then further subjected to 50% deformation. [Figure 6] This is the curve showing the change in electrical conductivity with respect to aging temperature and time after regression treatment of the copper alloy in Example 1 of the present invention and subsequent 80% deformation. [Figure 7] This is the curve showing the change in electrical conductivity with respect to aging temperature and time after regression treatment of a copper alloy in Example 1 of the present invention, followed by 80% deformation at 450°C for 2 hours, and then further deformation of 50%. [Figure 8] This is a bright-field image of the peak aging state of the copper alloy in Example 1 of the present invention. [Modes for carrying out the invention]

[0048] The technical solutions of the embodiments of this application will be described clearly and completely below, with reference to the drawings of the embodiments. Clearly, the embodiments described are only a selection of the embodiments of this application, not all of them. All other embodiments obtained by those skilled in the art without creative effort based on the embodiments of this application are within the scope of protection of this application.

[0049] The embodiments of the present invention provide a copper alloy material having high strength and high electrical conductivity, containing appropriate amounts of Cr, Hf, P, Ce, Zn, and Ag, which can achieve excellent overall performance. The present invention further provides a manufacturing process for the above-mentioned copper alloy material having high strength and high electrical conductivity.

[0050] To better understand the above solution, the present invention will be described in detail below with reference to examples. While many specific details are provided below to fully understand the present invention, it is possible to implement the invention in ways other than those described herein.

[0051] Example 1 In Example 1, a copper alloy material with high strength and high electrical conductivity was produced. The material composition consisted of 0.7 wt% Cr, 0.9 wt% Hf, 0.02 wt% P, 0.01 wt% Ce, 0.01 wt% Zn, and 0.02 wt% Ag by mass percentage, with the remainder being copper.

[0052] The method for producing the high-strength and high-electrical-conductivity copper alloy selected in Example 1 includes the following steps in the manufacturing process.

[0053] 1) A medium-frequency induction melting furnace was used to melt the materials in an atmospheric environment to obtain ingots. The raw materials used were Cu-Cr intermediate alloy (containing 10 wt% Cr), Cu-Hf intermediate alloy (containing 20 wt% Hf), Cu-Zn intermediate alloy (containing 20 wt% Zn), Cu-P intermediate alloy (containing 10 wt% P), pure Ce, pure Ag, and pure Zn. The raw materials, crucible, and mold were thoroughly preheated. The raw materials were preheated to 150°C, and the crucible and mold to 500°C, and then thoroughly dried.

[0054] Relatively strict requirements are in place for the order in which materials are added during the melting process, which effectively improves and guarantees the quality of the ingot. First, pure copper was placed in the crucible and the heating was started, and it was melted (1083°C). When the molten metal temperature reached 1250°C, pure Ag and pure Zn were added. The molten metal temperature was raised to 1400°C, and the Cu-Cr intermediate alloy was added in 3 to 4 batches, with the mixture held warm for 2 minutes after each addition, stirred for 60 seconds, and the surface of the molten metal coated with graphite. Subsequently, the Cu-Hf intermediate alloy, pure Ce, and Cu-P intermediate alloy were added, with the mixture held warm for 2 minutes and stirred for 60 seconds. After the molten metal temperature dropped to 1250°C, it was cast.

[0055] 2) After the melting process was complete, the ingots were subjected to a homogenization treatment and kept warm at 950°C for 4 hours.

[0056] 3) After cooling the ingot to 900°C by furnace cooling, the homogenized billet was subjected to hot working, employing a hot rolling method. The total deformation of the hot rolling was 80%, completed in 5 passes, with a pass deformation of 16%. After hot rolling was completed, water quenching was performed.

[0057] 4) After rough machining by hot deformation, the alloy was subjected to solid solution treatment, with a solid solution temperature of 950°C and a holding time of 2 hours, followed by water quenching.

[0058] 5) Pre-aging was performed on the alloy after solid solution treatment, with a pre-aging temperature of 500°C and a pre-aging time of 60 mins, and the cooling method was water quenching.

[0059] 6) Preliminary cold deformation was performed on the alloy after the completion of preliminary aging, using cold rolling as the method of preliminary cold deformation. The amount of cold rolling deformation was 40%, and it was completed in three passes, with the amount of deformation per pass controlled between 10% and 15%.

[0060] 7) After the preliminary aging was completed, the alloy underwent a regression treatment at 750°C for a holding time of 5 minutes, and the cooling method was water quenching.

[0061] 8) A composite deformation heat treatment was performed on the alloy after grain refinement was completed. This composite deformation heat treatment consisted of two deformations and two aging processes. The first cold rolling was performed on the sheet material at room temperature, with a total deformation of 80%, completed in three passes, and the deformation per pass was controlled between 10% and 30%. The first aging process was performed in a 450°C furnace for 2 hours. The second cold rolling was performed at room temperature, with a total deformation of 50%, completed in three passes, and the deformation per pass was controlled between 15% and 20%. The second aging process was performed in a 350°C furnace for 12 hours, yielding a novel copper alloy material with high strength and high electrical conductivity as investigated in this invention.

[0062] Figure 1 shows the manufacturing process route of an embodiment of the present invention.

[0063] Figure 2 shows the EBSD (Electron Back Scatter Diffraction) results after solid solution treatment of Example 1 of the present invention. It can be observed that after solid solution treatment, the crystal grain size is large, approximately 300 μm-400 μm.

[0064] Figure 3 shows the EBSD results after Example 1 of the present invention has undergone a series of grain refinement processes (preliminary aging, preliminary cold deformation, and regression treatment). Extensive recovery recrystallization has occurred in the grains, and the grain size has been effectively refined to approximately 10 μm to 30 μm.

[0065] Figures 4-7 show the curves of change in age hardness and electrical conductivity after Example 1 of the present invention undergoes composite deformation heat treatment, demonstrating a clear strengthening effect on the alloy.

[0066] Figure 8 shows the TEM observation results of the precipitated phase in the peak aging state, revealing that finely dispersed precipitated phase is distributed within the alloy matrix and that it clearly interacts with dislocations. This indicates that nanoscale precipitated phase particles effectively pin dislocation movement, improving the strength and toughness of the alloy. The final product has a tensile strength of 760 MPa, a hardness of 235 HV, and an electrical conductivity of 73% IACS.

[0067] A physical performance test was conducted on the high-strength and high-electrical-conductivity copper alloy material manufactured in Example 1, and the test results are shown in Table 1.

[0068] JPEG2026115026000002.jpg51170

[0069] Example 2 In Example 2, a copper alloy material with high strength and high electrical conductivity was produced. The material composition, by mass percentage, consisted of 0.4 wt% Cr, 0.6 wt% Hf, 0.02 wt% P, 0.02 wt% Ce, 0.02 wt% Zn, 0.01 wt% Ag, with the remainder being copper.

[0070] The method for manufacturing the copper alloy with high strength and high electrical conductivity selected in Example 2 includes the following steps in the manufacturing process.

[0071] 1) A medium-frequency induction furnace was used to melt the materials in an atmospheric environment to obtain ingots. The raw materials used were Cu-Cr intermediate alloy (containing 10 wt% Cr), Cu-Hf intermediate alloy (containing 20 wt% Hf), Cu-Zn intermediate alloy (containing 20 wt% Zn), Cu-P intermediate alloy (containing 10 wt% P), pure Ce, pure Ag, and pure Zn. The raw materials, crucible, and mold were thoroughly preheated. The raw materials were preheated to 150°C, and the crucible and mold to 400°C, and then thoroughly dried.

[0072] The order in which materials were added during the melting process was not changed. First, pure copper was placed in the crucible, and the heating was started until it melted (1083°C). When the molten metal temperature reached 1250°C, pure Ag and pure Zn were added. The molten metal temperature was raised to 1400°C, and the Cu-Cr intermediate alloy was added in 3 to 4 batches. After each addition, the mixture was kept warm for 2 minutes, stirred for 60 seconds, and the surface of the molten metal was coated with graphite. Subsequently, the Cu-Hf intermediate alloy, pure Ce, and Cu-P intermediate alloy were added, kept warm for 2 minutes, and stirred for 60 seconds. After the molten metal temperature dropped to 1250°C, it was cast.

[0073] 2) After the melting process was complete, the ingots were subjected to a homogenization treatment and kept warm at 950°C for 2 hours.

[0074] 3) After cooling the ingot to 900°C by furnace cooling, the homogenized billet was subjected to hot working, employing a hot rolling method. The total deformation of the hot rolling was 80%, completed in 5 passes, with a pass deformation of 16%. After hot rolling was completed, water quenching was performed.

[0075] 4) After rough machining by hot deformation, the alloy was subjected to solid solution treatment, with a solid solution temperature of 950°C and a holding time of 1 hour, followed by water quenching.

[0076] 5) Pre-aging was performed on the alloy after solid solution treatment, with a pre-aging temperature of 500°C and a pre-aging time of 30 mins, and the cooling method was water quenching.

[0077] 6) Preliminary cold deformation was performed on the alloy after the completion of preliminary aging, using cold rolling as the method of preliminary cold deformation. The amount of cold rolling deformation was 40%, and it was completed in three passes, with the amount of deformation per pass controlled between 10% and 15%.

[0078] 7) After the preliminary aging was completed, the alloy underwent a regression treatment at 750°C for a holding time of 5 minutes, and the cooling method was water quenching.

[0079] 8) A composite deformation heat treatment was performed on the alloy after grain refinement was completed. This composite deformation heat treatment consisted of two deformations and two aging processes. The first cold rolling was performed on the sheet material at room temperature, with a total deformation of 80%, completed in three passes, and the deformation per pass was controlled between 20% and 30%. The first aging process was performed in a 450°C furnace for 1 hour. The second cold rolling was performed at room temperature, with a total deformation of 50%, completed in three passes, and the deformation per pass was controlled between 15% and 20%. The second aging process was performed in a 350°C furnace for 12 hours, yielding a novel copper alloy material with high strength and high electrical conductivity as investigated in this invention.

[0080] Physical performance tests were conducted on the high-strength and high-electrical-conductivity copper alloy material manufactured in Example 2. The final product had a tensile strength of 673 MPa, a hardness of 206 HV, and an electrical conductivity of 72% IACS. The test results are shown in Table 2.

[0081] JPEG2026115026000003.jpg58170

[0082] Comparative Example 1 The composition of the CuCrHf alloy material produced in Comparative Example 1 is the same as in Example 1, and the raw material preparation and melting process in its manufacturing method are also the same as in Example 1, but the specific processing process is as follows.

[0083] 1) The preparation of raw materials and melting process are the same as in Example 1.

[0084] 2) After the melting process was complete, the ingots were subjected to a homogenization treatment and kept warm at 950°C for 4 hours.

[0085] 3) After cooling the ingot to 900°C by furnace cooling, the homogenized billet was subjected to hot working, employing a hot rolling method. The total deformation of the hot rolling was 80%, completed in 5 passes, with a pass deformation of 16%. After hot rolling was completed, water quenching was performed.

[0086] 4) After rough machining by hot deformation, the alloy was subjected to solid solution treatment, with a solid solution temperature of 950°C and a holding time of 2 hours, followed by water quenching.

[0087] 5) A composite deformation heat treatment was performed on the alloy after grain refinement was completed. This composite deformation heat treatment consisted of two deformations and two aging processes. The first cold rolling was performed on the sheet material at room temperature, with a total deformation of 80%, completed in three passes, and the deformation per pass was controlled between 10% and 30%. The first aging process was performed in a 450°C furnace for 2 hours. The second cold rolling was performed at room temperature, with a total deformation of 50%, completed in three passes, and the deformation per pass was controlled between 15% and 20%. The second aging process was performed in a 350°C furnace for 12 hours.

[0088] Physical performance tests were conducted on the high-strength and high-electrical-conductivity copper alloy material manufactured in Comparative Example 1. The final product had a tensile strength of 614 MPa, a hardness of 190 HV, and an electrical conductivity of 76% IACS. The test results are shown in Table 3.

[0089] JPEG2026115026000004.jpg55170

[0090] A comparison of the test results of Example 1 and Comparative Example 1 shows that the overall performance of Comparative Example 1 is clearly lower, and this difference is mainly due to the grain refinement treatment process (the final grain size of Example 1 was 3-8 μm, while that of Comparative Example was 6-13 μm). This indicates that a combination of pre-aging, pre-cold deformation, and regression processes can effectively control the precipitation order of the precipitated phase, refine the grain size of the alloy, and improve the overall performance of the alloy.

[0091] Comparative Example 2 The composition of the CuCrHf alloy material produced in Comparative Example 2 is the same as in Example 2, and the raw material preparation and melting process in its manufacturing method are also the same as in Example 1, but the specific processing process is as follows.

[0092] 1) The preparation of raw materials and melting process are the same as in Example 2.

[0093] 2) After the melting process was complete, the ingots were subjected to a homogenization treatment and kept warm at 950°C for 2 hours.

[0094] 3) After cooling the ingot to 900°C by furnace cooling, the homogenized billet was subjected to hot working, employing a hot rolling method. The total deformation of the hot rolling was 80%, completed in 5 passes, with a pass deformation of 16%. After hot rolling was completed, water quenching was performed.

[0095] 4) After rough machining by hot deformation, the alloy was subjected to solid solution treatment, with a solid solution temperature of 950°C and a holding time of 1 hour, followed by water quenching.

[0096] 5) A composite deformation heat treatment was performed on the alloy after grain refinement was completed. This composite deformation heat treatment consisted of two deformations and two aging processes. The first cold rolling was performed on the sheet material at room temperature, with a total deformation of 80%, completed in three passes, and the deformation per pass was controlled between 20% and 30%. The first aging process was performed in a furnace at 450°C for 1 hour. The second cold rolling was performed at room temperature, with a total deformation of 50%, completed in three passes, and the deformation per pass was controlled between 15% and 20%. The second aging process was performed in a furnace at 350°C for 12 hours, yielding a novel copper alloy material with high strength and high electrical conductivity as investigated in this invention.

[0097] Physical performance tests were conducted on the high-strength and high-electrical-conductivity copper alloy material manufactured in Comparative Example 2. The final product had a tensile strength of 591 MPa, a hardness of 174 HV, and an electrical conductivity of 79% IACS. The test results are shown in Table 4.

[0098] JPEG2026115026000005.jpg57170

[0099] A comparison of the test results of Example 2 and Comparative Example 2 once again demonstrated that the combination of pre-aging, pre-cold deformation, and regression processes can effectively control the precipitation order of the precipitated phase, refine the grain size of the alloy, and improve the overall performance of the alloy.

[0100] The technical features of the embodiments described above can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the embodiments described above have been described, but any combination of these technical features is considered to fall within the scope described herein, as long as there is no inconsistency.

[0101] The embodiments described above represent several embodiments of the present application, and while the descriptions are relatively specific and detailed, they should not be understood as limiting the scope of the claims. Furthermore, those skilled in the art can make some modifications and improvements without departing from the spirit of the present application, and all of these fall within the scope of protection. Therefore, the scope of protection of the present application should be based on the attached claims.

Claims

1. A copper alloy material having high strength and high electrical conductivity, characterized in that the copper alloy material contains, by mass percentage, 0.4 wt% to 1.5 wt% Cr, 0.6 wt% to 1.5 wt% Hf, 0 to 0.02 wt% P, 0 to 0.15 wt% Ce, 0 to 0.2 wt% Zn, 0 to 0.2 wt% Ag, with the remainder being Cu.

2. A copper alloy material having high strength and high electrical conductivity as described in claim 1, wherein the copper alloy material contains, by mass percentage, 0.4 wt% to 0.7 wt% Cr, 0.6 wt% to 0.9 wt% Hf, 0 to 0.02 wt% P, 0 to 0.02 wt% Ce, 0 to 0.02 wt% Zn, 0 to 0.2 wt% Ag, and the remainder being Cu, wherein the copper alloy material has high strength and high electrical conductivity.

3. The copper alloy material having high strength and high electrical conductivity according to claim 1 or 2, characterized in that there are interactions between a plurality of nanoscale precipitated phases and dislocations, which are pinned and entangled with each other and are finely and uniformly dispersed in the matrix, the crystal grain size of the copper alloy material having high strength and high electrical conductivity is 30 μm or less, and the crystal grains contain twins.

4. A method for producing a copper alloy material having high strength and high electrical conductivity as described in any one of claims 1 to 3, characterized in that first, each raw material is blended according to the ratio of the component design, melted to obtain an alloy solution, the alloy solution is cast to obtain a copper alloy ingot, then homogenization annealing, hot deformation treatment and solid solution treatment are performed sequentially on the copper alloy ingot to obtain a solid solution alloy material, and finally, pre-aging treatment, pre-cold deformation treatment, regression treatment and composite deformation heat treatment are performed sequentially on the solid solution alloy material to obtain a copper alloy material having high strength and high electrical conductivity.

5. A method for producing a copper alloy material having high strength and high electrical conductivity as described in claim 4, characterized in that pure copper, Cu-Cr intermediate alloy, Cu-Hf intermediate alloy, Cu-Zn intermediate alloy, Cu-P intermediate alloy, pure Ce, pure Ag, and pure Zn are blended according to a design ratio, the pure copper is first melted, the temperature is further raised to 1200°C to 1300°C, pure Ag and pure Zn are added, the temperature is further raised to 1300°C to 1400°C, the Cu-Cr intermediate alloy is added in 3 to 4 portions, the temperature is maintained for 2 min to 3 min, then stirred for 30 to 60 s, then Cu-Hf intermediate alloy, pure Ce, and Cu-P intermediate alloy are added, the temperature is maintained for 1 min to 2 min, and then cooled to 1200°C to 1300°C while stirring.

6. A method for manufacturing a copper alloy material having high strength and high electrical conductivity according to claim 4 or 5, characterized in that the melting is carried out in an atmospheric environment, graphite is coated onto the molten metal during the melting process, the casting temperature is 1200°C to 1450°C, and the mold preheating temperature is 400°C to 500°C.

7. A method for producing a copper alloy material having high strength and high electrical conductivity according to claim 4 or 5, wherein the temperature of the homogenization annealing treatment is 780°C to 980°C, and the duration of the homogenization annealing treatment is 2 hours to 8 hours. The hot deformation treatment is selected from hot forging or hot rolling, the temperature of the hot deformation treatment is 850°C to 950°C, the total deformation is 50% to 90%, and the deformation per pass is 10% to 20%. A method for producing a copper alloy material having high strength and high electrical conductivity, characterized in that the temperature of the solid solution treatment is 800°C to 1050°C, the duration of the solid solution treatment is 2 hours to 8 hours, and water quenching is performed after the completion of the solid solution treatment.

8. A method for manufacturing a copper alloy material having high strength and high electrical conductivity according to claim 4 or 5, wherein the pre-aging temperature is 350°C to 600°C, and the pre-aging time is 5 min to 480 min. The total deformation amount of the aforementioned preliminary cold deformation treatment is 40% to 90%, and the deformation amount per pass is in the range of 10% to 30%. A method for producing a copper alloy material having high strength and high electrical conductivity, characterized in that the temperature of the regression treatment is 750°C to 1000°C and the duration of the regression treatment is 10 s to 10 min.

9. The method for producing a copper alloy material having high strength and high electrical conductivity according to claim 4 or 5, characterized in that the composite deformation heat treatment consists of alternating cold deformation treatment and aging treatment.

10. A method for manufacturing a copper alloy material having high strength and high electrical conductivity as described in claim 9, wherein the composite deformation heat treatment consists of two cold deformations and two aging treatments, the deformation amount of the first cold deformation being 40% to 90% and the pass deformation amount being 10% to 30%. After the first cold deformation treatment, the first aging treatment is performed, followed by a second cold deformation treatment, the deformation amount of the second cold deformation treatment being 40% to 90% and the pass deformation amount being 10% to 30%. After the completion of the second cold deformation treatment, the second aging treatment is performed, wherein the temperature of the first aging treatment is 350°C to 600°C and the time is 5 min to 480 min, and the temperature of the second aging treatment is 350°C to 600°C and the time is 5 min to 480 min.

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