Cu-Cr-Zr alloy with low chromium content as well as preparation method and application of Cu-Cr-Zr alloy

Abstract

The invention relates to the technical field of non-ferrous metal processing, in particular to a low-chromium-content Cu-Cr-Zr alloy and a preparation method and application thereof.The low-chromium-content Cu-Cr-Zr alloy is prepared from, by mass, 0.3%-0.5% of Cr, 0.1%-0.4% of Zr, 0.05%-0.2% of Mg, 0.05%-0.3% of In, 0.02%-0.1% of La and the balance Cu; according to the method, through accurate quantitative control over key microelements such as Cr, Zr, Mg, In and rare earth element La in the Cu-Cr-Zr alloy and in combination with reasonable deformation and heat treatment processes, synergistic improvement of high strength and high conductivity is achieved; the tensile strength of the obtained Cu-Cr-Zr alloy can reach 600-650 MPa, the percentage elongation after fracture is 6-9%, and the conductivity reaches 80-85% IACS. Compared with the prior art, the high strength and high conductivity of the Cu-Cr-Zr alloy achieve the optimal balance of mechanical properties and electrical properties, show excellent comprehensive properties and are suitable for processing electronic devices with high strength and high conductivity requirements.

Description

Technical Field

[0001] The invention relates to the technical field of nonferrous metal processing, and in particular to a Cu-Cr-Zr alloy with a low chromium content, a preparation method thereof, and an application thereof. Background Art

[0002] Copper and copper alloys, thanks to their excellent electrical, thermal, and mechanical properties, are widely used in high-tech fields such as electronic information, integrated circuits, 5G communications, and new energy vehicles. However, as electronic devices evolve toward higher frequencies, higher speeds, and smaller sizes, copper alloys are facing increasingly stringent performance requirements. They must maintain both high conductivity and high strength to meet the stability and reliability demands of electronic components in complex environments. However, achieving both high strength and high conductivity remains a significant challenge for traditional copper alloys.

[0003] Currently, Cu-Cr-Zr alloys are a leading candidate material for the electronic information field due to their excellent overall performance. Although their electrical conductivity can exceed 80% IACS, a high Cr content is typically required to increase their tensile strength beyond the 600 MPa bottleneck. However, excessive Cr addition not only increases alloy cost but also exacerbates work hardening and brittleness, making subsequent processing more difficult and affecting product dimensional accuracy and service performance, thus limiting their adoption in extreme high-performance applications.

[0004] A lot of research has been carried out on this issue at home and abroad, mainly focusing on composition optimization, trace element addition and preparation process improvement. For example, Japan has developed a method for producing Cu-Cr-Zr alloys using non-vacuum production technology, and has successfully achieved industrialization, and has developed a variety of high-strength and high-conductivity Cu-Cr-Zr lead frame materials. In comparison, there is still a certain gap in composition design and process optimization in China. Due to the low solid solubility of Cr and Zr in the Cu matrix, coupled with the complex interactions between the elements, this type of alloy is extremely sensitive to smelting and heat treatment process parameters. Therefore, how to reduce the Cr content and minimize the total content of alloying elements as much as possible to achieve the coordinated optimization of high strength and high conductivity while ensuring the strength and conductivity of the alloy has become a key technical problem that needs to be solved in high-performance copper alloys for electronics. Summary of the Invention

[0005] In order to solve the above problems and improve the shortcomings of traditional Cu-Cr-Zr alloys, the present invention provides a low-chromium Cu-Cr-Zr alloy and its preparation method and application. By rationally controlling the Cr content and introducing trace elements such as Mg, In, and rare earth elements (La), the cost of the material is reduced. At the same time, the deformation and heat treatment processes are optimized, and a low-chromium Cu-Cr-Zr alloy with high strength, high conductivity, and excellent comprehensive performance is developed.

[0006] A Cu-Cr-Zr alloy with low chromium content comprises the following components by mass percentage: 0.3-0.5 wt.% Cr, 0.1-0.4 wt.% Zr, 0.05-0.2 wt.% Mg, 0.05-0.3 wt.% In, 0.02-0.1 wt.% La and the balance Cu.

[0007] Based on the components of the alloy, the present invention also provides a method for preparing a Cu-Cr-Zr alloy with a low chromium content, which includes smelting → homogenization → hot rolling → solution quenching → double-sided milling → multiple cold rolling and aging treatment processes, wherein the temperature of the homogenization process is 800-1000°C and the time is 2-8 hours; the starting rolling temperature of the hot rolling process is ≥850°C, and the finishing rolling temperature is ≥700°C.

[0008] Furthermore, during the hot rolling process, the reduction in each hot rolling pass is 10% to 30%, and the total deformation in each pass is 60% to 90%.

[0009] Furthermore, the multiple cold rolling and aging treatments include multiple cold rolling and multiple aging treatments, the multiple cold rollings include one rough cold rolling, two finishing cold rollings and three finishing cold rollings, the temperatures are all room temperature, and the deformation of each pass is 10% to 30%; the multiple aging treatments include one aging and two aging, both of which are carried out in a bell-type furnace protected by inert gas.

[0010] Furthermore, the total deformation amount of the first rough cold rolling is 50% to 90%, the total deformation amount of the second finishing cold rolling is 40% to 80%, and the total deformation amount of the third finishing cold rolling is 30% to 70%.

[0011] Furthermore, the temperature of the primary aging is 400-500° C., and the insulation time is 1-5 hours; the temperature of the secondary aging is 370-470° C., and the insulation time is 1-5 hours.

[0012] Furthermore, the smelting and mixing temperature of the metal raw materials during the smelting process is 1200-1300°C, and the alloy melt obtained after smelting and mixing is kept warm for 10-30 minutes at a temperature of 1200±10°C; wherein, the metal raw material is a metal element or an alloy, and the surface of the metal raw material is covered with charcoal during the smelting and mixing.

[0013] Furthermore, the solution quenching is carried out under the protection of an inert gas at a temperature of 900 to 1050°C.

[0014] Furthermore, the total depth of the double-sided milling is 1 mm.

[0015] The present invention also provides the use of the Cu-Cr-Zr alloy with low chromium content or the Cu-Cr-Zr alloy with low chromium content prepared by the preparation method in the processing of electronic devices with high strength and high electrical conductivity.

[0016] The advantages of the present invention are:

[0017] 1. The present invention focuses on the principle of low alloying in the design of alloy composition. On the basis of reducing the Cr element content, it not only ensures the uniform precipitation of the strengthening phase, but also avoids the adverse effect of excessive total element content on conductivity. Thus, while meeting the high strength requirements, it maintains excellent conductivity.

[0018] 2. The present invention adopts a multi-stage deformation and heat treatment collaborative process in the preparation process. The coordinated optimization of the process parameters at each stage ensures the homogenization of the alloy microstructure, fully stimulates the strengthening mechanism, and maximizes the improvement of the contradiction between the mechanical properties and electrical properties of the material, achieving an improvement in the comprehensive performance of high strength and high conductivity.

[0019] 3. The low-chromium content Cu-Cr-Zr alloy provided by the present invention is prepared by precise quantitative control of key trace elements such as Cr, Zr, Mg, In and rare earth element La in the Cu-Cr-Zr alloy, combined with reasonable deformation and heat treatment processes. The tensile strength of the Cu-Cr-Zr alloy can reach 600-650 MPa, the elongation after fracture is 6-9%, and the conductivity reaches 80-85% IACS. Compared with the existing technology, its high strength and high conductivity achieve the best balance between mechanical properties and electrical properties, showing excellent comprehensive performance, achieving a synergistic improvement of high strength and high conductivity, and is suitable for processing electronic devices with high strength and high conductivity requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0022] It should be noted that the various installation methods and technical terms mentioned in the present invention are technical terms that have long been clearly known in the relevant technical field and therefore will not be further explained. In addition, the same reference numerals are used for the same components, but this does not affect nor constitute an accurate understanding of the technical solution by those skilled in the art.

[0023] Example 1

[0024] This embodiment provides a Cu-Cr-Zr alloy with a low chromium content, as shown in Table 1 (Bal in the table is the abbreviation of Balance, representing the balance), which is composed of the following components, by mass percentage: Cr 0.38 wt.%, Zr 0.22 wt.%, Mg 0.2 wt.%, In 0.3 wt.%, La 0.1 wt.%, and the balance Cu.

[0025] The alloy is prepared using electrolytic Cu, Cu-Cr master alloy, metal Zr, Cu-Mg master alloy, Cu-In master alloy, and metal La as raw materials. The process flow is as follows: Figure 1 As shown, the process includes melting → homogenization → hot rolling → solution quenching → double-sided milling → multiple cold rolling and aging treatment. The specific steps are as follows:

[0026] Step 1. Melting:

[0027] The electrolytic Cu raw material is placed in a melting furnace and heated to 1250°C. If necessary, measures such as covering the metal surface with charcoal to prevent oxidation can be taken. After it is completely melted, Cu-Cr master alloy, metal Zr, Cu-Mg master alloy, Cu-In master alloy, and metal La are added to the molten metal, and the mixture is heated and kept warm, and stirred evenly to obtain a mixed melt. The smelted alloy melt is allowed to stand for 10 minutes and then deslagging is performed, and the temperature is maintained at 1200±10°C. The mixture is then cast into a preheated metal mold. After the ingot is cooled to room temperature, surface defects are removed to obtain a flat ingot.

[0028] Step 2. Homogenization:

[0029] The flat ingot obtained in step 1 was kept at 900° C. for 4 h to obtain a billet;

[0030] Step 3. Hot rolling:

[0031] The billet obtained after the homogenization treatment in step 2 is subjected to hot rolling deformation, with the starting rolling temperature being 880°C, the finishing rolling temperature being 720°C, the hot rolling pass reduction being 11%, and the total deformation being 77%;

[0032] Step 4. Solution quenching:

[0033] The alloy material after hot rolling in step 3 is subjected to online inert gas protection solution quenching at a solution temperature of 950°C;

[0034] Step 5. Double-sided milling:

[0035] The alloy obtained in step 4 was double-sided milled at a cutting speed of 15 m / min and a total double-sided milling depth of 1 mm to remove defects on the surface of the alloy after hot rolling and solid solution treatment;

[0036] Step 6. Multiple cold rolling and aging treatment:

[0037] (1) The alloy after double-sided milling in step 5 is subjected to a rough cold rolling at room temperature, with a pass deformation of 20% and a total deformation of 60%;

[0038] (2) The alloy after the primary cold rolling was then placed in a bell-type furnace for primary aging under inert gas protection at a temperature of 475°C for 3 hours;

[0039] (3) cooling the alloy after primary aging to room temperature and performing secondary cold rolling at room temperature with a deformation of 10% per pass and a total deformation of 70%;

[0040] (4) The alloy after secondary cold rolling is placed in a bell-type furnace under inert gas protection for secondary aging at a temperature of 420°C for 5 hours;

[0041] (5) Finally, the alloy after secondary aging is cooled to room temperature, and then subjected to three times of finish cold rolling at room temperature, with each pass deformation of 10% and a total deformation of 50%, to finally obtain a Cu-Cr-Zr alloy with a low chromium content.

[0042] Example 2

[0043] The alloy composition and preparation method of this embodiment are the same as those of Example 1, except that the mass percentage of each component and the parameters of the preparation process are different:

[0044] As shown in Table 1, the present embodiment consists of the following components, by mass percentage: 0.32 wt.% Cr, 0.18 wt.% Zr, 0.14 wt.% Mg, 0.27 wt.% In, 0.10 wt.% La, and the balance Cu.

[0045] In this embodiment, the temperature during the smelting process in step 1 is 1200° C. and the standing time is 30 minutes.

[0046] In this embodiment, the temperature during the homogenization treatment in step 2 is 800° C. and the holding time is 8 hours.

[0047] In this embodiment, the pass reduction during the hot rolling process in step 3 is 10%, and the total deformation is 80%.

[0048] In this embodiment, the temperature during the solution quenching process in step 4 is 1000°C.

[0049] In this embodiment, during the multiple cold rolling and aging processes in step 6, the deformation of the first rough cold rolling pass is 10%, and the total deformation is 70%; the temperature of the first aging process is 475°C, and the holding time is 2 hours; the deformation of the second finish cold rolling pass is 11%, and the total deformation is 66%; the temperature of the second aging process is 425°C, and the holding time is 2 hours; the deformation of the third finish cold rolling pass is 10%, and the total deformation is 50%.

[0050] Example 3

[0051] The alloy composition and preparation method of this embodiment are the same as those of Example 1, except that the mass percentage of each component and the parameters of the preparation process are different:

[0052] As shown in Table 1, the present embodiment consists of the following components, in terms of mass percentage: 0.35 wt.% Cr, 0.32 wt.% Zr, 0.1 wt.% Mg, 0.14 wt.% In, 0.02 wt.% La, and the balance Cu.

[0053] In this embodiment, the temperature during the smelting process in step 1 is 1300° C. and the standing time is 10 minutes.

[0054] In this embodiment, the temperature during the homogenization treatment in step 2 is 850° C. and the holding time is 6 hours.

[0055] In this embodiment, the pass reduction during the hot rolling process in step 3 is 20%, and the total deformation is 70%.

[0056] In this embodiment, the temperature during the solution quenching process in step 4 is 1000°C.

[0057] In this embodiment, during the multiple cold rolling and aging treatment processes in step 6, the deformation of the first rough cold rolling pass is 10%, and the total deformation is 70%; the temperature of the first aging process is 450°C, and the holding time is 3 hours; the deformation of the second finish cold rolling pass is 10%, and the total deformation is 80%; the temperature of the second aging process is 400°C, and the holding time is 4 hours; the deformation of the third finish cold rolling pass is 10%, and the total deformation is 40%.

[0058] Example 4

[0059] The alloy composition and preparation method of this embodiment are the same as those of Example 1, except that the mass percentage of each component and the parameters of the preparation process are different:

[0060] As shown in Table 1, the present embodiment consists of the following components, in terms of mass percentage: Cr 0.40 wt.%, Zr 0.35 wt.%, Mg 0.05 wt.%, In 0.05 wt.%, La 0.02 wt.%, and the balance Cu.

[0061] In this embodiment, the temperature during the homogenization treatment in step 2 is 850° C. and the holding time is 8 hours.

[0062] In this embodiment, the pass reduction during the hot rolling process in step 3 is 10%, and the total deformation is 70%.

[0063] In this embodiment, during the multiple cold rolling and aging treatments in step 6, the deformation of the first rough cold rolling pass is 15%, and the total deformation is 75%; the temperature of the first aging is 450°C, and the holding time is 3 hours; the deformation of the second finish cold rolling pass is 10%, and the total deformation is 50%; the temperature of the second aging is 450°C, and the holding time is 2 hours; the deformation of the third finish cold rolling pass is 10%, and the total deformation is 40%.

[0064] Example 5

[0065] The alloy composition and preparation method of this embodiment are the same as those of Example 1, except that the mass percentage of each component and the parameters of the preparation process are different:

[0066] As shown in Table 1, the present embodiment consists of the following components, in percentage by mass: 0.50 wt.% Cr, 0.40 wt.% Zr, 0.13 wt.% Mg, 0.12 wt.% In, 0.05 wt.% La, and the balance Cu.

[0067] In this embodiment, the temperature during the homogenization treatment in step 2 is 950° C. and the holding time is 2 hours.

[0068] In this embodiment, the pass reduction during the hot rolling process in step 3 is 20%, and the total deformation is 80%.

[0069] In this embodiment, the temperature during the solution quenching process in step 4 is 980°C.

[0070] In this embodiment, during the multiple cold rolling and aging treatments in step 6, the temperature of the first aging process is 400° C. and the holding time is 5 hours; the deformation of the second finishing cold rolling pass is 10%, and the total deformation is 50%; the temperature of the second aging is 470° C. and the holding time is 1.5 hours; the deformation of the third finishing cold rolling pass is 15%, and the total deformation is 30%.

[0071] Example 6

[0072] The alloy composition and preparation method of this embodiment are the same as those of Example 1, except that the mass percentage of each component and the parameters of the preparation process are different:

[0073] As shown in Table 1, the present embodiment consists of the following components, in terms of mass percentage: 0.46 wt.% Cr, 0.10 wt.% Zr, 0.16 wt.% Mg, 0.18 wt.% In, 0.05 wt.% La, and the balance Cu.

[0074] In this embodiment, the temperature during the homogenization treatment in step 2 is 800° C. and the holding time is 5 hours.

[0075] In this embodiment, the pass reduction during the hot rolling process in step 3 is 15%, and the total deformation is 60%.

[0076] In this embodiment, the temperature during the solution quenching process in step 4 is 1050°C.

[0077] In this embodiment, during the multiple cold rolling and aging treatment processes in step 6, the deformation of the first rough cold rolling pass is 10%, and the total deformation is 70%; the temperature of the first aging process is 500°C, and the holding time is 1 hour; the deformation of the second finish cold rolling pass is 20%, and the total deformation is 80%; the temperature of the second aging process is 370°C, and the holding time is 5 hours; the deformation of the third finish cold rolling pass is 10%, and the total deformation is 30%.

[0078] Comparative Example 1

[0079] The preparation method and process parameters of this comparative example are the same as those of Example 1, except that In and La elements are not added to the alloy composition of this comparative example. As shown in Table 1, this comparative example consists of the following components, by mass percentage: 0.38 wt.% Cr, 0.22 wt.% Zr, 0.2 wt.% Mg, and the balance Cu.

[0080] Comparative Example 2

[0081] The alloy composition and mass percentage of each component in this comparative example are the same as those in Example 1 (as shown in Table 1), except that the parameters of the preparation process are different:

[0082] In this comparative example, the temperature during the homogenization treatment in step 2 is 700° C. and the holding time is 1 hour.

[0083] Comparative Example 3

[0084] The alloy composition and mass percentage of each component in this comparative example are the same as those in Example 1 (as shown in Table 1), except that the parameters of the preparation process are different:

[0085] In this embodiment, the starting rolling temperature during the hot rolling process in step 3 is 750°C, and the finishing rolling temperature is 600°C.

[0086] Table 1 Composition of Cu-Cr-Zr alloys by weight

[0087] Cr Zr Mg In La Cu Example 1 0.38 0.22 0.20 0.30 0.10 Bal Example 2 0.32 0.18 0.14 0.27 0.10 Bal Example 3 0.35 0.32 0.10 0.14 0.02 Bal Example 4 0.40 0.35 0.05 0.05 0.02 Bal Example 5 0.50 0.40 0.13 0.12 0.05 Bal Example 6 0.46 0.10 0.16 0.18 0.05 Bal Comparative Example 1 0.38 0.22 0.20 — — Bal Comparative Example 2 0.38 0.22 0.20 0.30 0.10 Bal Comparative Example 3 0.38 0.22 0.20 0.30 0.10 Bal

[0088] Test Example 1

[0089] In this test example, the Cu-Cr-Zr alloys obtained in Examples 1-6 and Comparative Examples 1-3 were subjected to comprehensive performance tests on strength, electrical conductivity, and tensile properties. The results are shown in Table 2:

[0090] Table 2 Comprehensive performance test table of Cu-Cr-Zr alloys of embodiments and comparative examples

[0091]

[0092] As can be seen from the data in Table 2, the composition and content of the alloy will affect the comprehensive performance of the Cu-Cr-Zr alloy. Compared with comparative examples 1-3, the mechanical properties and electrical properties of Examples 1-5 of the present invention are balanced, and the comprehensive performance is excellent. Among them, although the yield strength and tensile strength of Examples 4 and 5 are higher than those of other examples, their elongation and conductivity are relatively low; although the elongation and conductivity of Example 2 are higher than those of other examples, its yield strength and tensile strength are relatively low; although the tensile strength and conductivity of Example 6 are higher than those of other examples, its yield strength and elongation are relatively low; it can be seen that Examples 1 and 3 show a better balance of mechanical and electrical properties than Examples 2 and Examples 4-6, and have excellent comprehensive performance; and Example 1 has the best overall comprehensive performance effect and is the optimal embodiment of this application.

[0093] From the comparison of the results of Examples 1-6 of the present invention with those of Comparative Example 1 in Table 2, it can be seen that in Examples 1-6, the addition of In and La plays an important role in the comprehensive performance of the alloy. The In element helps to refine the grains of the alloy, improve the solid solution strengthening effect, and optimize the distribution of the precipitated phase, so that the alloy precipitates evenly during the subsequent heat treatment process; La, as a rare earth element, has the function of purifying the melt, can remove impurities, improve the purity of the alloy, and also strengthen the fine grains; while the alloy composition of Comparative Example 1 lacks In and La elements, and its yield strength, tensile strength and conductivity are significantly reduced, and the comprehensive performance is poor, indicating that these two elements have a significant contribution to improving the performance of the alloy. Therefore, if In and La are missing from the alloy composition, it is difficult to achieve the excellent performance of Example 1, indicating that the role of In and La in this alloy system is necessary. The addition of In and La elements helps to improve both the mechanical properties and the conductive properties, promotes fine grain strengthening and improves interface bonding, and improves the comprehensive performance of the alloy.

[0094] Comparing the results of Examples 1-6 with Comparative Examples 2 and 3 shows that the preparation process also affects the overall performance of Cu-Cr-Zr alloys. The results of Comparative Example 2 demonstrate that the temperature and duration of the homogenization treatment also have a significant impact on the alloy's performance. The purpose of homogenization treatment is to eliminate component segregation in the as-cast structure and fully diffuse the alloying elements to obtain a uniform initial structure. The results of Comparative Example 3 also demonstrate that temperature control during the hot rolling process plays a crucial role in the alloy's deformability and ultimate performance.

[0095] The homogenization process in Comparative Example 2 was conducted at a temperature of 700°C and a holding time of 1 hour, which were significantly lower than the temperatures (800°C to 1000°C) and holding times (2 to 8 hours) used in Examples 1-6. This resulted in poor structural uniformity in the alloy, affecting the stability of the subsequent deformation process and resulting in relatively poor mechanical properties. Therefore, if the temperature is too low or the holding time is too short, it will be difficult to eliminate component segregation, which may lead to problems such as uneven work hardening and abnormal recrystallization structure during subsequent processing, further affecting the overall performance of the alloy.

[0096] This embodiment strictly requires that the hot rolling start temperature be ≥850°C and the final rolling temperature be ≥700°C, while the hot rolling start temperature of Comparative Example 3 is reduced to 750°C and the final rolling temperature is reduced to 600°C, which are significantly lower than the temperatures of Examples 1-6, resulting in severe work hardening of the alloy, prone to cracking, and reduced plasticity. At the same time, due to the low hot rolling final rolling temperature, the grains may not be fully dynamically recrystallized, resulting in limited deformation capacity during subsequent cold rolling, affecting the alloy's elongation and electrical conductivity. The strict control of the start rolling temperature and the final rolling temperature during the hot rolling process of this embodiment ensures good deformation capacity and microstructure evolution control of the alloy during hot working, thereby improving the overall performance of the material. This shows that hot rolling temperatures below the appropriate range will also increase the deformation resistance of the alloy, reduce the uniformity of the rolling process, and may also result in higher residual stress in the final product, affecting the overall performance.

[0097] Furthermore, controlling the temperature and time of the smelting process is crucial. The smelting temperature in this embodiment is 1200°C to 1300°C, and slag removal is performed after the melt has been allowed to rest for 10 to 30 minutes. A lower smelting temperature (<1200°C) may result in incomplete dissolution of alloying elements, affecting compositional uniformity, while increasing impurity content and reducing the overall quality of the alloy. Excessively high smelting temperatures (>1300°C) may exacerbate the loss of volatile elements, such as Mg and In, causing the alloy composition to deviate from the designed value. Furthermore, high temperatures may exacerbate oxidation reactions, forming inclusions and affecting final performance. Furthermore, insufficient smelting time may result in insufficient diffusion of alloying elements and uneven composition, while excessive smelting time may lead to excessive oxidation, affecting alloy purity.

[0098] In summary, the present invention comprehensively considers the influence of each element on the structure and performance of Cu-Cr-Zr alloys when designing the composition. By precisely controlling the content of Cr, Zr, Mg, In and La (rare earth elements), the Cr element content is reduced, which plays a significant role in reducing alloy costs and improving alloy performance. Specifically, Cr and Zr, as core strengthening elements, form nanoscale Cr precipitation phases and Cu5Zr precipitation phases, respectively, and improve strength through precipitation strengthening and grain boundary pinning effects; Mg element plays a role through solid solution strengthening and inhibits the coarsening of Cr phase, while synergistically optimizing the distribution of precipitation phases with In element, reducing electron scattering, and having a good improvement effect on the comprehensive mechanical and electrical properties; the introduction of La element further purifies the matrix, and its reaction with impurities such as oxygen and sulfur significantly improves the purity of the alloy; the total alloy element content is low, avoiding the negative impact of excessive solid solution atoms on conductivity, and achieving the best balance between strength and conductivity.

[0099] At the same time, the smelting process of the present invention can avoid problems such as insufficient melting of high-melting-point elements and burnout of trace elements and easily oxidized elements, thereby improving the accuracy and uniformity of the chemical composition of the ingot. The process flow adopts a multi-stage deformation-aging collaborative process to achieve good adaptation between process parameters, which can promote the full precipitation of the precipitated phase and improve the comprehensive performance of the alloy. The Cu-Cr-Zr alloy designed by the present invention has excellent comprehensive performance, with a tensile strength of 600-650MPa, an elongation after fracture of 6-9%, and a conductivity of 80-85% IACS, and has excellent mechanical and conductive properties.

[0100] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention may be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the foregoing description. It is intended that all variations that fall within the meaning and range of equivalents of the claims be embraced within the present invention. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0101] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any minor modifications, equivalent replacements, and improvements made to the above embodiments based on the technical essence of the present invention shall be included in the scope of protection of the technical solution of the present invention.

Claims

1. A Cu-Cr-Zr alloy with a low chromium content, characterized in that: Calculated by mass percentage, the material includes the following components: 0.3-0.5 wt. % Cr, 0.1-0.4 wt. % Zr, 0.05-0.2 wt. % Mg, 0.05-0.3 wt. % In, 0.02-0.1 wt. % La and the balance Cu.

2. A method for preparing a Cu-Cr-Zr alloy with a low chromium content according to claim 1, comprising the steps of: smelting → homogenization → hot rolling → solution quenching → double-sided milling → multiple cold rolling and aging treatment, wherein: The temperature of the homogenization process is 800-1000° C., and the time is 2-8 hours; the starting rolling temperature of the hot rolling process is ≥850° C., and the finishing rolling temperature is ≥700° C.

3. The method for preparing a Cu-Cr-Zr alloy with a low chromium content according to claim 2, characterized in that: During the hot rolling process, the reduction per pass is 10% to 30%, and the total deformation per pass is 60% to 90%.

4. The method for preparing a Cu-Cr-Zr alloy with a low chromium content according to claim 2, characterized in that: The multiple cold rolling and aging treatments include multiple cold rolling and multiple aging treatments, wherein the multiple cold rolling includes one rough cold rolling, two finishing cold rollings and three finishing cold rollings, all at room temperature, and each pass deformation is 10% to 30%; the multiple aging treatments include one aging and two agings, both of which are carried out in a bell-type furnace protected by inert gas.

5. The method for preparing a Cu-Cr-Zr alloy with a low chromium content according to claim 4, characterized in that: The total deformation amount of the first rough cold rolling is 50% to 90%, the total deformation amount of the second finishing cold rolling is 40% to 80%, and the total deformation amount of the third finishing cold rolling is 30% to 70%.

6. The method for preparing a Cu-Cr-Zr alloy with a low chromium content according to claim 4, characterized in that: The temperature of the primary aging is 400-500° C., and the temperature is kept at 1-5 hours; the temperature of the secondary aging is 370-470° C., and the temperature is kept at 1-5 hours.

7. The method for preparing a Cu-Cr-Zr alloy with a low chromium content according to claim 2, characterized in that: During the smelting process, the smelting and mixing temperature of the metal raw materials is 1200-1300° C., and the alloy melt obtained after smelting and mixing is kept warm and allowed to stand for 10-30 minutes at a temperature of 1200±10° C.; wherein, the metal raw materials are single metals or alloys, and the surface of the metal raw materials is covered with charcoal during the smelting and mixing.

8. The method for preparing a Cu-Cr-Zr alloy with a low chromium content according to claim 2, wherein: The solid solution quenching is carried out under the protection of an inert gas at a temperature of 900-1050°C.

9. The method for preparing a Cu-Cr-Zr alloy with a low chromium content according to claim 2, wherein: The total depth of the double-sided milling is 1 mm.

10. Use of the low-chromium-content Cu-Cr-Zr alloy according to claim 1 or the low-chromium-content Cu-Cr-Zr alloy prepared by the preparation method according to any one of claims 2 to 9 in the processing of high-strength and high-conductivity electronic devices.

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