High-strength high-conductivity high-heat-resistance Cu-Cr-Hf alloy and preparation method thereof

Abstract

A high-strength, high-conductivity and high-heat-resistance Cu-Cr-Hf alloy and a preparation method thereof belong to the technical field of copper alloy materials, and the copper alloy material is composed of the following components in percentage by weight: Cr: 0.15-0.45%, Hf: 0.15-0.45%, and the balance being Cu. The method comprises the following steps: Step 1, vacuum arc melting to prepare Cu-10Cr intermediate alloy and Cu-10Hf intermediate alloy. Step 2, vacuum induction melting. Step 3, homogenization treatment. Step 4, hot rolling treatment. Step 5, solid solution treatment. Step 6, cold rolling treatment. Step 7, aging treatment. The tensile strength of the obtained Cu-Cr-Hf alloy is 465-628 Mpa, the electrical conductivity is 76.2-81.1% IACS, the softening resistance temperature is 512-570 DEG C, and the elongation after fracture is 8.0%-11.8%. The preparation process adopted by the application has low cost and high application value, and the solidification and heat treatment processes do not need a magnetic induction device; the application can ensure high tensile strength, high electrical conductivity and softening resistance temperature, and at the same time has good high-temperature stability and plasticity.

Description

Technical Field

[0001] This invention belongs to the technical field of copper alloy materials, and relates to a high-strength, high-conductivity, and high-heat-resistant Cu-Cr-Hf alloy material and its preparation method. Background Technology

[0002] Copper and copper alloys, with their high electrical and thermal conductivity, excellent plasticity, and corrosion resistance, are irreplaceable basic functional materials in the fields of electronics, electrical engineering, rail transportation, and high-end equipment manufacturing. Pure copper has excellent electrical and thermal conductivity, but its room temperature strength is relatively low, which cannot meet the requirements of high-power conductive components and high-temperature service components. Conventional copper alloys generally suffer from the inherent contradiction that increasing strength inevitably sacrifices conductivity, making it difficult to simultaneously achieve a balance of high strength, high conductivity, and resistance to high-temperature softening. Cu-Cr alloys are advanced copper-based alloy systems composed of copper as the matrix, chromium as the main alloying element, and supplemented with trace alloying elements. This series of alloys can form nanoscale Cr precipitates through aging heat treatment, thereby significantly improving the precipitation strengthening effect while maintaining excellent electrical and thermal conductivity and good corrosion resistance. As can be seen from the literature "Preparation Process and Solidification Structure Study of High Chromium Cu-Cr Alloys [D], Dong Bowen, Dalian University of Technology, 2017, pp. 17-26", however, "as the temperature increases, the precipitates are prone to coarsening or dissolving, leading to a significant decrease in the strength of the alloy."

[0003] Current Cu-Cr alloy strengthening methods all employ alloying, using trace alloying elements such as Zr, Ti, and Mg to achieve a synergistic effect of solid solution strengthening and precipitation strengthening. According to the literature "Research Status of High-Strength, High-Conductivity Cu-Cr-Zr Alloys, Tao Yeqing et al., Hot Working Technology, 2010, 39(14):31-33+36", "The addition of Zr not only refines the grains but also forms composite precipitates with Cr (such as Cu5Zr), thus significantly improving the age-hardening effect of the alloy." This alloy system typically contains 0.15-0.35 wt.% Cr and 0.08-0.25 wt.% Zr. By precisely controlling the composition and heat treatment process, a tensile strength exceeding 500 MPa can be achieved while maintaining a high electrical conductivity of over 80% IACS. However, under non-vacuum melting conditions, Zr is easily oxidized and burned off. Furthermore, controlling and precisely controlling the content of Zr during the smelting process is challenging and not suitable for large-scale industrial production. According to the literature "Influence of Trace Ti / Co Elements on the Microstructure and Properties of Cu-Cr Alloy, Fang Hang et al., Guangzhou Chemical Industry, 2021, 49(17):58-60", "The addition of Ti inhibits the growth of Cr precipitates. The average size of the precipitates decreases with the increase of Ti content. The precipitates are mainly spherical and coffee bean-shaped Cr phases, and Ti atoms exist in the matrix in a solid solution state." By adding an appropriate amount of Ti and optimizing the heat treatment process, Cu-Cr-Ti alloy can obtain good comprehensive properties. After aging at 500 ℃ for 60 minutes, the hardness of Cu-0.3Cr-0.05Ti alloy is 162.6 HV, the electrical conductivity is 82.2% IACS, and the tensile strength is 510MPa. However, Ti can only be added in trace amounts. Once the addition exceeds the threshold, the conductivity will drop sharply. According to the literature "The Influence of Magnesium-Silicon Composite Microalloying on the Aging Process of High Strength and High Conductivity Copper-Chromium-Zirconium Alloy, Hou Dongjian et al., Metal Heat Treatment, 2016, 41(10):102-107", "Mg segregation at the phase interface not only promotes the nucleation of precipitates, but also inhibits the coarsening of precipitates by hindering grain boundary migration, significantly refining the size of precipitates. At the same time, Mg solid solution increases the recrystallization temperature, inhibits the recovery of the structure by pinning dislocations, and stabilizes the substructure generated by cold deformation. However, the potential of Mg and its oxides is lower than that of copper matrix. Under humid, ammonia-containing, acid and alkaline conditions, microgalvanic corrosion will form, preferentially failing along the grain boundary, greatly reducing the corrosion resistance of the alloy."

[0004] Therefore, in existing technologies, traditional Cu-Cr binary alloys exhibit poor high-temperature stability, with precipitated phases easily coarsening and dissolving under high-temperature conditions, leading to severe strength degradation. Conventional Zr, Ti, and Mg microalloyed Cu-Cr alloys all have significant technical shortcomings: Cu-Cr-Zr alloys are prone to oxidation and burn-off, and composition control is difficult, hindering industrial mass production; Cu-Cr-Ti alloys have an extremely narrow composition window, where exceeding trace element limits significantly sacrifices electrical conductivity; and Cu-Cr-Mg alloys suffer from poor corrosion resistance and weak adaptability to various operating conditions. Modified copper alloys cannot simultaneously achieve a comprehensive range of properties including high strength, high conductivity, high heat resistance, easy mass production, and excellent corrosion resistance. They are ill-suited to the stringent service requirements of high-end fields such as liquid rocket engines, high-end electronic components, and rail transit contact wires, which demand high temperatures, high strength, and high conductivity. Therefore, there is an urgent need to develop a new copper-chromium alloy with controllable composition, simple process, and scalable production, while also possessing excellent mechanical properties, high conductivity, and ultra-high resistance to high-temperature softening. This would solve the technical problem of existing copper alloys having difficulty in synergistically matching strength, conductivity, and heat resistance, and limiting their industrial applications. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a high-strength, high-conductivity, and high-heat-resistant Cu-Cr-Hf alloy material and its preparation method. This invention, through the rational proportioning of trace alloying elements Cr and Hf, combined with an integrated preparation process of vacuum melting, multi-stage deformation, and precise temperature-controlled heat treatment, effectively regulates the microstructure of the alloy matrix, constructs a stable dual-scale precipitate phase system, and significantly improves the precipitation strengthening effect and high-temperature structural stability of the alloy. This results in a high-strength, high-conductivity, and high-heat-resistant Cu-Cr-Hf alloy material that satisfies both high tensile strength and high electrical conductivity while also exhibiting high resistance to softening. This achieves a synergistic unity of multiple properties of copper alloys—high strength, high conductivity, and high heat resistance—overcoming the technical bottlenecks of traditional copper alloys, such as the trade-off between strength and conductivity, easy softening at high temperatures, poor stability of modifying elements, and difficulty in industrial mass production.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A high-strength, high-conductivity, and high-heat-resistant Cu-Cr-Hf alloy material, calculated by weight percentage, is composed of the following components: Cr: 0.15~0.45%, Hf: 0.15~0.45%, with the balance being Cu.

[0007] The Cu-Cr-Hf alloy exhibits a tensile strength of 465~628 MPa, a conductivity of 76.2~81.1% IACS, a softening temperature of 512~570 ℃, and an elongation after fracture of 8.0%~11.8%. Thus, it combines high tensile strength, high conductivity, and a high softening temperature with good high-temperature stability and plasticity.

[0008] Preferably, the Cr element is the Cr in the Cu-10Cr master alloy, and the Hf element is the Hf in the Cu-10Hf master alloy.

[0009] A method for preparing the high-strength, high-conductivity, and high-heat-resistant Cu-Cr-Hf alloy material includes the following steps: Step 1: Vacuum arc melting to prepare Cu-10Cr master alloy and Cu-10Hf master alloy; A Cu-10Cr master alloy was prepared by vacuum arc melting of pure chromium and high-purity copper particles, with a chromium content of 10 wt.%. A Cu-10Hf master alloy was prepared by vacuum arc melting of pure hafnium and high-purity copper particles, with a hafnium content of 10 wt.%. Furthermore, the parameters for vacuum arc melting are: output voltage of 32-36 V, output current of 1000-1500 A, and frequency of 50 Hz.

[0010] Step 2, Vacuum induction melting: Place the prepared high-purity copper, Cu-10Cr master alloy, and Cu-10Hf master alloy into a graphite crucible, and melt them under vacuum. After the metal is completely melted, keep it at the temperature for a period of time, and then cast it into an alloy ingot to obtain an alloy sample. Furthermore, the melting temperature is 1150-1250℃, and the holding time is 10-30 min.

[0011] Step 3, Homogenization treatment: The alloy sample obtained in Step 2 is homogenized, followed by milling and fine grinding. The homogenization temperature is 940-980℃, the homogenization time is 20-28 h, and the heating rate is 10℃ / min.

[0012] Step 4, hot rolling: The alloy sample obtained in step 3 is subjected to hot rolling, with a deformation of 2 mm per pass and a total deformation of 30%. Step 5, Solution treatment: The alloy sample obtained in Step 4 is solution treated in a reducing atmosphere, followed by milling and fine polishing. The solution temperature is 1000-1060℃, the solution time is 1-5 h, and the heating rate is 10 ℃ / min.

[0013] Furthermore, the reducing atmosphere is CO.

[0014] Step 6, Cold rolling: The alloy sample obtained in Step 5 is subjected to cold rolling, with a deformation of 2 mm per pass and a total deformation of 90%. Step 7, Aging Treatment: The alloy sample obtained in Step 6 is subjected to aging treatment. The aging temperature is 420-480℃, the aging time is 1-3 h, and the heating rate is 10 ℃ / min.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) At the eutectic temperature, Hf has a higher solubility in copper than Zr. Adding Hf to Cu-Cr alloy will produce a strong precipitation strengthening effect, and replacing Zr with Hf will improve the high temperature stability of Cu-Cr alloy, increasing the softening temperature to 570℃.

[0016] (2) The high-strength, high-conductivity, and heat-resistant copper alloy material prepared by this invention possesses excellent mechanical and electrical properties, and its high-temperature stability is superior to that of Cu-Cr, Cu-Cr-Zr, and Cu-Cr-Ti alloys. It is a key material for liquid rocket engines, electronic components, and track contact wires. In addition, the preparation process adopted by this invention has low cost and high application value, and neither the solidification nor the heat treatment process requires a magnetic induction device. Detailed Implementation

[0017] The present invention will be further described in detail below with reference to examples.

[0018] Example 1: In this embodiment, the Cu-Cr-Hf alloy material has the following alloy composition by weight percentage: Cr: 0.15 wt.%; Hf: 0.45 wt.%; with the balance being Cu. The Cr element used is the same as that in the Cu-10Cr master alloy, and the Hf element used is the same as that in the Cu-10Hf master alloy.

[0019] The preparation method of the high-strength, high-conductivity, and high-heat-resistant Cu-Cr-Hf alloy material in this embodiment includes the following steps: Step 1: Vacuum arc melting to prepare Cu-10Cr master alloy and Cu-10Hf master alloy; A Cu-10Cr master alloy was prepared by vacuum arc melting pure chromium and high-purity copper particles to produce a master alloy, wherein the chromium content was 10 wt.%. A Cu-10Hf master alloy was prepared by vacuum arc melting pure hafnium and high-purity copper particles to produce a master alloy, wherein the hafnium content was 10 wt.%. In this embodiment, the parameters for vacuum arc melting are: output voltage of 32 V, output current of 1000 A, and frequency of 50 Hz.

[0020] Step 2, Vacuum induction melting: Place the prepared high-purity copper, Cu-10Cr master alloy, and Cu-10Hf master alloy into a graphite crucible, and melt them under vacuum at a temperature of 1250 ℃. After the metal is completely melted, hold it at that temperature for 10 min, and then cast it into an alloy ingot to obtain an alloy sample. Step 3, Homogenization treatment: The alloy sample obtained in Step 2 is homogenized, followed by milling and fine grinding. The homogenization temperature is 940 ℃, the homogenization time is 20 h, and the heating rate is 10 ℃ / min.

[0021] Step 4, hot rolling: The alloy sample obtained in step 3 is subjected to hot rolling, with a deformation of 2 mm per pass and a total deformation of 30%. Step 5, Solution treatment: The alloy sample obtained in Step 4 is solution treated in a reducing atmosphere (CO), followed by milling and fine polishing. The solution temperature is 1000 ℃, the solution time is 1 h, and the heating rate is 10 ℃ / min.

[0022] Step 6, Cold rolling: The alloy sample obtained in Step 5 is subjected to cold rolling, with a deformation of 2 mm per pass and a total deformation of 90%. Step 7, Aging Treatment: The alloy sample obtained in Step 6 is subjected to aging treatment. The aging temperature is 420 ℃, the aging time is 1 h, and the heating rate is 10 ℃ / min.

[0023] The Cu-Cr-Hf alloy sample obtained in this embodiment has a tensile strength of 478 MPa, a conductivity of 81.1% IACS, an elongation after fracture of 9.5%, and a softening temperature of 512℃. The increase in softening temperature gives it higher high-temperature stability, with a relative softening temperature of about 12℃ higher than that of Cu-Cr alloy (500℃).

[0024] Example 2: In this embodiment, the Cu-Cr-Hf alloy material has the following alloy composition by weight percentage: Cr: 0.3 wt.%; Hf: 0.3 wt.%; with the balance being Cu. The Cr element used is the Cr from the Cu-10Cr master alloy, and the Hf element used is the Hf from the Cu-10Hf master alloy.

[0025] The preparation method of the high-strength, high-conductivity, and high-heat-resistant Cu-Cr-Hf alloy material in this embodiment includes the following steps: Step 1: Vacuum arc melting to prepare Cu-10Cr master alloy and Cu-10Hf master alloy; A Cu-10Cr master alloy was prepared by vacuum arc melting pure chromium and high-purity copper particles to produce a master alloy, wherein the chromium content was 10 wt.%. A Cu-10Hf master alloy was prepared by vacuum arc melting pure hafnium and high-purity copper particles to produce a master alloy, wherein the hafnium content was 10 wt.%. In this embodiment, the parameters for vacuum arc melting are: output voltage of 36 V, output current of 1500 A, and frequency of 50 Hz.

[0026] Step 2, Vacuum induction melting: Place the prepared high-purity copper, Cu-10Cr master alloy, and Cu-10Hf master alloy into a graphite crucible, and melt them under vacuum at a temperature of 1150 ℃. After the metal is completely melted, hold it at that temperature for 30 min, and then cast it into an alloy ingot to obtain an alloy sample. Step 3, Homogenization treatment: The alloy sample obtained in Step 2 is homogenized, followed by milling and fine grinding. The homogenization temperature is 940 ℃, the homogenization time is 20 h, and the heating rate is 10 ℃ / min.

[0027] Step 4, hot rolling: The alloy sample obtained in step 3 is subjected to hot rolling, with a deformation of 2 mm per pass and a total deformation of 30%. Step 5, Solution treatment: The alloy sample obtained in Step 4 is solution treated in a reducing atmosphere (CO), followed by milling and fine polishing. The solution temperature is 1000 ℃, the solution time is 1 h, and the heating rate is 10 ℃ / min.

[0028] Step 6, Cold rolling: The alloy sample obtained in Step 5 is subjected to cold rolling, with a deformation of 2 mm per pass and a total deformation of 90%. Step 7, Aging Treatment: The alloy sample obtained in Step 6 is subjected to aging treatment. The aging temperature is 420 ℃, the aging time is 1 h, and the heating rate is 10 ℃ / min.

[0029] The Cu-Cr-Hf alloy sample obtained in this embodiment has a tensile strength of 568 MPa, a conductivity of 79.8% IACS, an elongation after fracture of 11.8%, and a softening temperature of 532℃. The increase in softening temperature gives it higher high-temperature stability, with a relative softening temperature of approximately 32℃ higher than that of the Cu-Cr alloy (500℃).

[0030] Example 3: The Cu-Cr-Hf alloy material in this embodiment has the following alloy composition by weight percentage: Cr: 0.45 wt.%; Hf: 0.15 wt.%; with the balance being Cu. The Cr element used is the Cr from the Cu-10Cr master alloy, and the Hf element used is the Hf from the Cu-10Hf master alloy.

[0031] The preparation method of the high-strength, high-conductivity, and high-heat-resistant Cu-Cr-Hf alloy material in this embodiment includes the following steps: Step 1: Vacuum arc melting to prepare Cu-10Cr master alloy and Cu-10Hf master alloy; A Cu-10Cr master alloy was prepared by vacuum arc melting pure chromium and high-purity copper particles to produce a master alloy, wherein the chromium content was 10 wt.%. A Cu-10Hf master alloy was prepared by vacuum arc melting pure hafnium and high-purity copper particles to produce a master alloy, wherein the hafnium content was 10 wt.%. In this embodiment, the parameters for vacuum arc melting are: output voltage of 34 V, output current of 1250 A, and frequency of 50 Hz.

[0032] Step 2, Vacuum induction melting: Place the prepared high-purity copper, Cu-10Cr master alloy, and Cu-10Hf master alloy into a graphite crucible, and melt them under vacuum at a temperature of 1200 ℃. After the metal is completely melted, hold it at that temperature for 20 min, and then cast it into an alloy ingot to obtain an alloy sample. Step 3, Homogenization treatment: The alloy sample obtained in Step 2 is homogenized, followed by milling and fine grinding. The homogenization temperature is 960℃, the homogenization time is 24 h, and the heating rate is 10 ℃ / min.

[0033] Step 4, hot rolling: The alloy sample obtained in step 3 is subjected to hot rolling, with a deformation of 2 mm per pass and a total deformation of 30%. Step 5, Solution treatment: The alloy sample obtained in Step 4 is solution treated in a reducing atmosphere (CO), followed by milling and fine polishing. The solution temperature is 1030℃, the solution time is 3 h, and the heating rate is 10 ℃ / min.

[0034] Step 6, Cold rolling: The alloy sample obtained in Step 5 is subjected to cold rolling, with a deformation of 2 mm per pass and a total deformation of 90%. Step 7, Aging Treatment: The alloy sample obtained in Step 6 is subjected to aging treatment. The aging temperature is 450℃, the aging time is 2 h, and the heating rate is 10 ℃ / min.

[0035] The Cu-Cr-Hf alloy sample obtained in this embodiment has a tensile strength of 465 MPa, a conductivity of 77.8% IACS, an elongation after fracture of 8.5%, and a softening temperature of 560℃. The increase in softening temperature gives it higher high-temperature stability, with a relative softening temperature of Cu-Cr alloy (500℃) that is about 60℃ higher.

[0036] Example 4: In this embodiment, the Cu-Cr-Hf alloy material has the following composition by weight percentage: Cr: 0.45 wt.%; Hf: 0.3 wt.%; with the balance being Cu. The Cr element used is the same as that in the Cu-10Cr master alloy, and the Hf element used is the same as that in the Cu-10Hf master alloy.

[0037] The preparation method of the high-strength, high-conductivity, and high-heat-resistant Cu-Cr-Hf alloy material in this embodiment includes the following steps: Step 1: Vacuum arc melting to prepare Cu-10Cr master alloy and Cu-10Hf master alloy; A Cu-10Cr master alloy was prepared by vacuum arc melting pure chromium and high-purity copper particles to produce a master alloy, wherein the chromium content was 10 wt.%. A Cu-10Hf master alloy was prepared by vacuum arc melting pure hafnium and high-purity copper particles to produce a master alloy, wherein the hafnium content was 10 wt.%. In this embodiment, the parameters for vacuum arc melting are: output voltage of 34 V, output current of 1250 A, and frequency of 50 Hz.

[0038] Step 2, Vacuum induction melting: Place the prepared high-purity copper, Cu-10Cr master alloy, and Cu-10Hf master alloy into a graphite crucible, and melt them under vacuum at a temperature of 1200 ℃. After the metal is completely melted, hold it at that temperature for 15 min, and then cast it into an alloy ingot to obtain an alloy sample. Step 3, Homogenization treatment: The alloy sample obtained in Step 2 is homogenized, followed by milling and fine grinding. The homogenization temperature is 940 ℃, the homogenization time is 28 h, and the heating rate is 10 ℃ / min.

[0039] Step 4, hot rolling: The alloy sample obtained in step 3 is subjected to hot rolling, with a deformation of 2 mm per pass and a total deformation of 30%. Step 5, Solution treatment: The alloy sample obtained in Step 4 is solution treated in a reducing atmosphere (CO), followed by milling and fine polishing. The solution temperature is 1000 ℃, the solution time is 5 h, and the heating rate is 10 ℃ / min.

[0040] Step 6, Cold rolling: The alloy sample obtained in Step 5 is subjected to cold rolling, with a deformation of 2 mm per pass and a total deformation of 90%. Step 7, Aging Treatment: The alloy sample obtained in Step 6 is subjected to aging treatment. The aging temperature is 420 ℃, the aging time is 3 h, and the heating rate is 10 ℃ / min.

[0041] The Cu-Cr-Hf alloy sample obtained in this embodiment has a tensile strength of 610 MPa, a conductivity of 78.0% IACS, an elongation after fracture of 11%, and a softening temperature of 570 °C. The increase in softening temperature gives it higher high-temperature stability, with a relative softening temperature of approximately 70 °C higher than that of the Cu-Cr alloy (500 °C).

[0042] Example 5: In this embodiment, the Cu-Cr-Hf alloy material has the following composition by weight percentage: Cr: 0.45 wt.%; Hf: 0.45 wt.%; with the balance being Cu. The Cr element used is the same as that in the Cu-10Cr master alloy, and the Hf element used is the same as that in the Cu-10Hf master alloy.

[0043] The preparation method of the high-strength, high-conductivity, and high-heat-resistant Cu-Cr-Hf alloy material in this embodiment includes the following steps: Step 1: Vacuum arc melting to prepare Cu-10Cr master alloy and Cu-10Hf master alloy; A Cu-10Cr master alloy was prepared by vacuum arc melting pure chromium and high-purity copper particles to produce a master alloy, wherein the chromium content was 10 wt.%. A Cu-10Hf master alloy was prepared by vacuum arc melting pure hafnium and high-purity copper particles to produce a master alloy, wherein the hafnium content was 10 wt.%. In this embodiment, the parameters for vacuum arc melting are: output voltage of 34 V, output current of 1250 A, and frequency of 50 Hz.

[0044] Step 2, Vacuum induction melting: Place the prepared high-purity copper, Cu-10Cr master alloy, and Cu-10Hf master alloy into a graphite crucible, and melt them under vacuum at a temperature of 1200 ℃. After the metal is completely melted, hold it at that temperature for 10 min, and then cast it into an alloy ingot to obtain an alloy sample. Step 3, Homogenization treatment: The alloy sample obtained in Step 2 is homogenized, followed by milling and fine grinding. The homogenization temperature is 980 ℃, the homogenization time is 20 h, and the heating rate is 10 ℃ / min.

[0045] Step 4, hot rolling: The alloy sample obtained in step 3 is subjected to hot rolling, with a deformation of 2 mm per pass and a total deformation of 30%. Step 5, Solution treatment: The alloy sample obtained in Step 4 is solution treated in a reducing atmosphere (CO), followed by milling and fine polishing. The solution temperature is 1060 ℃, the solution time is 1 h, and the heating rate is 10 ℃ / min.

[0046] Step 6, Cold rolling: The alloy sample obtained in Step 5 is subjected to cold rolling, with a deformation of 2 mm per pass and a total deformation of 90%. Step 7, Aging Treatment: The alloy sample obtained in Step 6 is subjected to aging treatment. The aging temperature is 480 ℃, the aging time is 1 h, and the heating rate is 10 ℃ / min.

[0047] The Cu-Cr-Hf alloy sample obtained in this embodiment has a tensile strength of 628 MPa, a conductivity of 76.6% IACS, an elongation after fracture of 8%, and a softening temperature of 555℃. The increase in softening temperature gives it higher high-temperature stability, with a relative softening temperature of approximately 55℃ higher than that of the Cu-Cr alloy (500℃).

[0048] Example 6: In this embodiment, the Cu-Cr-Hf alloy material has the following composition by weight percentage: Cr: 0.45 wt.%; Hf: 0.45 wt.%; with the balance being Cu. The Cr element used is the same as that in the Cu-10Cr master alloy, and the Hf element used is the same as that in the Cu-10Hf master alloy.

[0049] The preparation method of the high-strength, high-conductivity, and high-heat-resistant Cu-Cr-Hf alloy material in this embodiment includes the following steps: Step 1: Vacuum arc melting to prepare Cu-10Cr master alloy and Cu-10Hf master alloy; A Cu-10Cr master alloy was prepared by vacuum arc melting pure chromium and high-purity copper particles to produce a master alloy, wherein the chromium content was 10 wt.%. A Cu-10Hf master alloy was prepared by vacuum arc melting pure hafnium and high-purity copper particles to produce a master alloy, wherein the hafnium content was 10 wt.%. In this embodiment, the parameters for vacuum arc melting are: output voltage of 36 V, output current of 1500 A, and frequency of 50 Hz.

[0050] Step 2, Vacuum induction melting: Place the prepared high-purity copper, Cu-10Cr master alloy, and Cu-10Hf master alloy into a graphite crucible, and melt them under vacuum at a temperature of 1250 ℃. After the metal is completely melted, hold it at that temperature for 30 min, and then cast it into an alloy ingot to obtain an alloy sample. Step 3, Homogenization treatment: The alloy sample obtained in Step 2 is homogenized, followed by milling and fine grinding. The homogenization temperature is 960 ℃, the homogenization time is 24 h, and the heating rate is 10 ℃ / min.

[0051] Step 4, hot rolling: The alloy sample obtained in step 3 is subjected to hot rolling, with a deformation of 2 mm per pass and a total deformation of 30%. Step 5, Solution treatment: The alloy sample obtained in Step 4 is solution treated in a reducing atmosphere (CO), followed by milling and fine polishing. The solution temperature is 1030 ℃, the solution time is 3 h, and the heating rate is 10 ℃ / min.

[0052] Step 6, Cold rolling: The alloy sample obtained in Step 5 is subjected to cold rolling, with a deformation of 2 mm per pass and a total deformation of 90%. Step 7, Aging Treatment: The alloy sample obtained in Step 6 is subjected to aging treatment. The aging temperature is 460 ℃, the aging time is 2 h, and the heating rate is 10 ℃ / min.

[0053] The Cu-Cr-Hf alloy sample obtained in this embodiment has a tensile strength of 612 MPa, a conductivity of 76.2% IACS, an elongation after fracture of 8.1%, and a softening temperature of 548℃. The increase in softening temperature gives it higher high-temperature stability, with a relative softening temperature of approximately 48℃ higher than that of the Cu-Cr alloy (500℃).

[0054] The above specific examples are further detailed descriptions of the present invention and should not be construed as limiting the specific embodiments of the present invention to these examples. Appropriate adjustments and improvements to the composition can be made without departing from the alloy composition range and deformation heat treatment process proposed in the present invention, but all such adjustments and improvements should be considered to fall within the protection scope of the claims submitted in this invention.

Claims

1. A method for preparing a high-strength, high-conductivity, and high-heat-resistant Cu-Cr-Hf alloy, characterized in that, The preparation method includes the following steps: Step 1: Vacuum arc melting to prepare Cu-10Cr master alloy and Cu-10Hf master alloy; A Cu-10Cr master alloy was prepared by vacuum arc melting of pure chromium and high-purity copper particles, with a chromium content of 10 wt.%. A Cu-10Hf master alloy was prepared by vacuum arc melting of pure hafnium and high-purity copper particles, with a hafnium content of 10 wt.%. Step 2, Vacuum induction melting: Place the prepared high-purity copper, Cu-10Cr master alloy, and Cu-10Hf master alloy into a graphite crucible, draw a vacuum for melting, and after the metal is completely melted, hold it at the temperature and then cast it into an alloy ingot to obtain an alloy sample. Step 3, Homogenization treatment: The alloy sample is homogenized, and then milled and finely polished. Step 4, hot rolling: The alloy sample obtained in step 3 is subjected to hot rolling, with a deformation of 2 mm per pass and a total deformation of 30%. Step 5, solution treatment: The alloy sample obtained in step 4 is solution treated in a reducing atmosphere, followed by milling and fine polishing; the solution temperature is 1000-1060℃, and the solution time is 1-5 h. Step 6, Cold rolling: The alloy sample obtained in Step 5 is subjected to cold rolling, with a deformation of 2 mm per pass and a total deformation of 90%. Step 7, Aging treatment: The alloy sample obtained in step 6 is subjected to aging treatment at an aging temperature of 420-480℃ for 1-3 hours.

2. The method for preparing a high-strength, high-conductivity, and high-heat-resistant Cu-Cr-Hf alloy according to claim 1, characterized in that, In step 1, the parameters for vacuum arc melting are: output voltage of 32-36 V, output current of 1000-1500 A, and frequency of 50 Hz.

3. The method for preparing a high-strength, high-conductivity, and high-heat-resistant Cu-Cr-Hf alloy according to claim 1, characterized in that, In step 2, the melting temperature is 1150-1250℃ and the holding time is 10-30 min.

4. The method for preparing a high-strength, high-conductivity, and high-heat-resistant Cu-Cr-Hf alloy according to claim 1, characterized in that, In step 3, the homogenization temperature is 940-980℃, the homogenization time is 20-28 h, and the heating rate is 10 ℃ / min.

5. The method for preparing a high-strength, high-conductivity, and high-heat-resistant Cu-Cr-Hf alloy according to claim 1, characterized in that, In step 5, the reducing atmosphere is CO.

6. The method for preparing a high-strength, high-conductivity, and high-heat-resistant Cu-Cr-Hf alloy according to claim 1, characterized in that, In step 7, the heating rate is 10 °C / min.

7. A high-strength, high-conductivity, and high-heat-resistant Cu-Cr-Hf alloy material, characterized in that, Prepared by any one of the preparation methods described in claims 1-6, the Cu-Cr-Hf alloy material comprises, by weight percentage, the following components. Composition: Cr: 0.15~0.45%, Hf: 0.15~0.45%, balance Cu.

8. The high-strength, high-conductivity, and high-heat-resistant Cu-Cr-Hf alloy material according to claim 7, characterized in that, The Cu-Cr-Hf alloy has a tensile strength of 465~628 MPa, a conductivity of 76.2~81.1% IACS, a softening temperature of 512~570 ℃, and an elongation after fracture of 8.0%~11.8%.

9. The high-strength, high-conductivity, and high-heat-resistant Cu-Cr-Hf alloy material according to claim 7, characterized in that, The Cr element is the Cr in the Cu-10Cr master alloy, and the Hf element is the Hf in the Cu-10Hf master alloy.