Method for preparing high-strength and high-conductivity Cu-Ni-Si-Fe alloy based on powder metallurgy technology

Abstract

The invention provides a method for preparing a high-strength and high-conductivity Cu-Ni-Si-Fe alloy based on a powder metallurgy technology, and belongs to the field of copper alloy materials. The method comprises the steps that firstly, Cu-Ni-Si-Fe alloy powder is prepared through the gas atomization technology, then the Cu-Ni-Si-Fe alloy powder is put into a graphite mold to be subjected to hot pressing sintering, an alloy blank is obtained, then the alloy blank is subjected to solid solution, rolling and aging treatment, and the final Cu-Ni-Si-Fe alloy material is obtained. According to the preparation method, spherical Cu-Ni-Si-Fe alloy powder uniform in size and component is obtained through a gas atomization technical method, the structure uniformity of a green body is further improved through a powder metallurgy technology, and finally the Cu-Ni-Si-Fe alloy excellent in mechanical and electrical properties is obtained through hot working. According to the method, the steps are reasonable in design and closely matched, and the problems that in the prior art, when the Cu-Ni-Si alloy is prepared through smelting and casting, structure components are not uniform, and the strength and conductivity of the Cu-Ni-Si alloy are insufficient are effectively solved.

Description

Technical Field

[0001] The present invention relates to a method for preparing high-strength and high-conductivity Cu-Ni-Si-Fe alloy based on powder metallurgy technology, belonging to the field of copper alloy materials. Background Art

[0002] Cu-Ni-Si alloy is widely used in the fields of electronic devices, conductive connectors, and marine engineering due to its excellent mechanical properties, electrical conductivity, and corrosion resistance. However, the mismatch between strength and conductivity has always been the main problem of Cu-Ni-Si alloy. Adding trace alloying elements to Cu-Ni-Si alloy will affect the precipitation process of the alloy, such as accelerating the precipitation of precipitated phases, inhibiting the growth of precipitated phases and grain size growth, etc. This process will improve the mechanical and electrical properties of the material. Therefore, selecting appropriate alloying elements and controlling their addition amounts in the alloy are the main means to enhance the properties of Cu-Ni-Si alloy. Fe element is a cheap metal, which can accelerate the precipitation of precipitated phases to a certain extent and prevent the coarsening of precipitated phases. At the same time, the addition of Fe in the alloy helps to refine grains, make the microstructure of the alloy more uniform and fine, and can delay the recrystallization process of the Cu matrix, thereby improving the comprehensive properties of the alloy. In addition, compared with Cu-Ni-Si alloy, adding an appropriate amount of Fe can reduce the production cost of the alloy to a certain extent.

[0003] Jiang Yanbin et al. obtained low-cost high-strength and high-conductivity copper alloy materials by adding an appropriate amount of Fe element to Cu-Ni-Si alloy through the melting and casting method. However, in this melting and casting process, the dispersion problem of Fe element and the non-uniformity during the solidification process are likely to cause composition segregation, resulting in defects such as pores, porosity, and inclusions. These composition segregations and defects are difficult to completely eliminate during subsequent heat treatment and processing, and will ultimately affect the mechanical and electrical properties of the alloy. Therefore, there is an urgent need for a new preparation method to make Fe element uniformly dispersed in the copper alloy and prepare a Cu-Ni-Si series alloy with better matching of mechanical and electrical properties. Summary of the Invention

[0004] In order to solve the dispersion problem of Fe element in the melting and casting method, overcome the defects such as composition segregation, pores, and inclusions existing in the preparation of Cu-Ni-Si series alloy, and meet the requirement of excellent matching between strength and conductivity. The present invention proposes a method for preparing high-strength and high-conductivity Cu-Ni-Si-Fe alloy based on powder metallurgy technology. By adding Fe powder to the mixed metal liquid of Cu-Ni-Si alloy, and then using gas atomization method to prepare Cu-Ni-Si-Fe spherical alloy powder with uniform composition, and then preparing Cu-Ni-Si-Fe alloy material through sintering, solution treatment, rolling, and aging treatment.

[0005] A method for preparing a high-strength and high-conductivity Cu-Ni-Si-Fe alloy based on powder metallurgy technology, comprising the following steps: (1) Preparation of Cu-Ni-Si-Fe alloy powder: Put three materials, namely high-purity electrolytic Cu plate, high-purity electrolytic Ni plate and high-purity electrolytic Si plate, into a vacuum induction melting furnace for melting to obtain a uniformly mixed Cu-Ni-Si alloy molten metal; slowly add pure Fe powder into the molten metal and stir to obtain a uniformly composed Cu-Ni-Si-Fe molten metal, and let the molten metal flow into the atomization chamber through a diversion tube. A high-speed gas stream exerts a huge impact on the molten metal, generating strong shear force and impact force, breaking it into filaments or small droplets. These droplets fly downward in the atomization chamber and are quickly cooled to obtain uniformly sized spherical powders of Cu-Ni-Si-Fe alloy; (2) Preparation of Cu-Ni-Si-Fe alloy block: Add the Cu-Ni-Si-Fe powder obtained in step (1) into a graphite mold for densification sintering. Take out the sample after the temperature cools below room temperature to obtain a sintered blank of Cu-Ni-Si-Fe alloy; (3) Hot working treatment: Perform high-temperature solution treatment on the sintered blank of Cu-Ni-Si-Fe alloy obtained in step (2) to obtain a supersaturated Cu-Ni-Si-Fe alloy block; perform multi-pass rolling treatment on it, and finally perform low-temperature aging treatment to obtain a Cu-Ni-Si-Fe alloy material.

[0006] Preferably, in step (1), the melting temperature is: 1400 °C to 1500 °C.

[0007] Preferably, in step (1), the atomizing gas is high-purity argon, the pressure is 3 MPa to 5 MPa, and the flow rate is 400 m 3 / h to 500 m 3 / h.

[0008] Preferably, in step (1), the addition amount of Fe powder is 0.8 wt% to 1.2 wt%.

[0009] Preferably, in step (2), the sintering temperature is 800 °C to 900 °C, the heating rate is 50 °C / min to 150 °C / min, and the holding time is 5 min to 15 min.

[0010] Preferably, in step (3), the temperature of the solution treatment is 900 °C to 1000 °C, the time is 1 h to 2 h, and it is cooled by water quenching.

[0011] Preferably, in step (3), the temperature of the rolling treatment is 500 °C to 600 °C, the number of rolling passes is 3 to 5 times, and the rolling reduction per pass is 1 mm to 1.5 mm.

[0012] Preferably, in step (3), the temperature of the aging treatment is 300 °C to 500 °C, the time of the aging treatment is 1 h to 3 h, and it is cooled by water quenching.

[0013] Advantages of the present invention (1) Through the gas atomization powder-making process, the present invention forms spherical powders with uniform and small sizes, solves problems such as composition segregation from the source, combines powder metallurgy densification sintering, avoids the generation of pores and porosity defects, and significantly improves the density of the obtained alloy billets.

[0014] (2) By adding a trace amount of Fe element and regulating the hot working process, the present invention further improves the performance of the material, realizes the mutual matching of the strength and conductivity of the alloy. The addition of the Fe element significantly refines the grain size of the alloy and also significantly improves the uniformity of the microstructure. At the same time, the use amount of metal Cu is reduced by replacing it with the inexpensive Fe element, and combined with the short process of powder metallurgy, the production cost of the material is effectively reduced. (3) Through the technical method of gas atomization, the present invention obtains spherical Cu-Ni-Si-Fe alloy powders with uniform sizes and compositions. Through powder metallurgy technology, the uniformity of the billet structure is further improved. Finally, by adjusting the hot working process, a Cu-Ni-Si-Fe alloy with excellent mechanical and electrical properties is obtained; the design of each step of this method is reasonable and closely coordinated, effectively solving the problems of uneven tissue composition and insufficient strength and conductivity of Cu-Ni-Si alloy in the existing technology during melting and casting to prepare Cu-Ni-Si alloy. Description of the drawings

[0015] Figure 1 It is the SEM morphology diagram of the Cu-Ni-Si-Fe alloy powder prepared by gas atomization.

[0016] Figure 2 It is the XRD diagram of the Cu-Ni-Si-Fe alloy powder prepared by gas atomization.

[0017] Figure 3 It is the TEM diagram of the Cu-Ni-Si-Fe alloy in Example 2.

[0018] Figure 4 It is the tensile property comparison diagram of Example 1 and Comparative Example 1.

[0019] Figure 5 It is the hardness and conductivity comparison diagram of Example 1 and Comparative Example 1.

[0020] Figure 6 Tensile property comparison chart of Example 2 and Comparative Example 2

[0021] Figure 7 Hardness and conductivity comparison chart of Example 2 and Comparative Example 2

[0022] Figure 8 Tensile property comparison chart of Example 3 and Comparative Example 3

[0023] Figure 9 Hardness and conductivity comparison chart of Example 3 and Comparative Example 3

[0024] Figure 10 Tensile property comparison chart of Example 3, Comparative Example 4 and Comparative Example 5

[0025] Figure 11 Hardness and conductivity comparison chart of Example 3, Comparative Example 4 and Comparative Example 5 Detailed implementation manners

[0026] Next, the technical solutions of the present invention will be described in detail and comprehensively. It should be noted that the described embodiments only represent a part of the present invention and do not cover all embodiments. At the same time, all other embodiments that can be obtained by those skilled in the art based on the embodiments provided by the present invention without creative efforts should also fall within the protection scope of the present invention. In the following embodiments, unless otherwise specified, the instruments and materials used are commercially available.

[0027] In the following embodiments: Electrolytic Cu plate and electrolytic Ni plate: The purity is 99.9% for both, and the manufacturer is Tianjin Hongsheng Metal Materials Co., Ltd.; Industrial-grade polycrystalline Si: The purity > 97%, and the manufacturer is Lingshou Tengyun Mineral Products Processing Factory; Scanning electron microscope: Nova Nano-450, FEI, USA; Transmission electron microscope: SA 58000x, FEI, USA.

[0028] Microhardness tester: DHV1000CCD, Shanghai Yanrun Optical Machine Technology Co., Ltd.; Eddy current conductivity meter: Sigma 2008B, Xiamen Tianyan Instrument Co., Ltd.; Mechanical property characterization of Ti3SiC2 / Cu-Ni-Si composite materials in examples and comparative examples: A universal tensile testing machine (AUTO STC8800, Japan) was used to conduct tensile experiments at room temperature, and the tensile rate was 0.2 mm / min.

[0029] Example 1 A method for preparing high-strength and high-conductivity Cu-Ni-Si-Fe alloy based on powder metallurgy technology, and the specific preparation steps are as follows: (1) Preparation of Cu-Ni-Si-Fe alloy powder: Put three materials, namely high-purity electrolytic Cu plate, high-purity electrolytic Ni plate and high-purity electrolytic Si plate, into a vacuum induction melting furnace for melting at 1400 °C to obtain a uniformly mixed Cu-Ni-Si alloy molten metal; slowly add pure Fe powder with a mass fraction of 0.8 wt% into the molten metal and stir to obtain a uniformly composed Cu-Ni-Si-Fe molten metal. Let the molten metal flow into the atomization chamber through a diversion tube. Under the condition of a protective gas of argon, with a pressure of 3 MPa and a flow rate of 400 m 3 / h, a high-speed gas flow exerts a huge impact on the molten metal, generating strong shear force and impact force, breaking it into filaments or small droplets. These droplets fly downward in the atomization chamber and are quickly cooled to obtain Cu-Ni-Si-Fe alloy spherical powder with uniform size; (2) Preparation of Cu-Ni-Si-Fe alloy block: Take 20 g of the Cu-Ni-Si-Fe powder obtained in step (1) and add it into a graphite mold. Through spark plasma sintering, keep it at 800 °C for 5 min, with a heating rate of 50 °C / min. After the temperature is cooled below room temperature, take out the sample to obtain a Cu-Ni-Si-Fe alloy sintered blank with a thickness of 6 mm; (3) Hot working treatment: Perform solution treatment on the Cu-Ni-Si-Fe alloy sintered blank obtained in step (2) at 1000 °C for 2 h, and then water quench and cool to obtain a supersaturated Cu-Ni-Si-Fe alloy block; then perform rolling treatment at a temperature of 500 °C, with an opening temperature of 500 °C, a holding time of 15 min, 5 rolling passes, a reduction of 1 mm per pass, and a total reduction of 5 mm to obtain a Cu-Ni-Si-Fe alloy strip blank with a thickness of 1 mm. Finally, perform aging treatment at 300 °C for 3 h, and then water quench and cool to finally obtain the Cu-Ni-Si-Fe alloy.

[0030] The morphology of the Cu-Ni-Si-Fe alloy powder prepared by gas atomization in Example 1 is as Figure 1 shown. It can be seen that the size of the alloy is uniform, the average particle size is 4.4 μm, and the sphericity is good, which is convenient for the subsequent pressing and sintering of the powder.

[0031] The Cu-Ni-Si-Fe alloy powder prepared by gas atomization in Example 1 was subjected to XRD test, and the results are as Figure 2As shown, it can be observed that the XRD pattern of Cu-Ni-Si-Fe is composed of three main characteristic diffraction peaks of Cu. However, all these diffraction peaks have shifted towards higher angles. This is because Ni, Si, and Fe elements are uniformly solid-solved in the powder, resulting in a decrease in the lattice plane spacing d of Cu and a decrease in the unit cell parameter. According to Bragg's equation, the diffraction peaks will shift to the right towards larger angles.

[0032] Comparative Example 1 The Cu-Ni-Si-Fe alloy was prepared by the melting and casting method, and the specific operation steps are as follows: (1) Put three materials, namely high-purity electrolytic Cu plate, high-purity electrolytic Ni plate, and industrial-grade polysilicon, into a vacuum induction melting furnace for melting. Then, slowly add pure Fe powder with a mass fraction of 0.8 wt% into the molten metal and stir to obtain a molten Cu-Ni-Si alloy, which is cast into an alloy ingot with dimensions of 100 mm (length) × 60 mm (width) × 25 mm (thickness); (2) Process the alloy ingot obtained in step (1) into an initial billet with dimensions of 60 mm (length) × 40 mm (width) × 20 mm (thickness). Then, homogenize it at 900 °C for 2 h to obtain a homogeneous block. Roll the homogeneous block at 800 °C for 4 passes, with a reduction per pass of 3.5 mm, to obtain a block with a thickness of 6 mm; (3) Solution-treat the alloy block obtained in step (2) at 1000 °C for 2 h and cool it by water quenching to obtain a solution-treated block. Then, roll the solution-treated block at 500 °C. The opening temperature is 500 °C, the holding time is 15 min, the number of rolling passes is 5 passes, and the reduction per pass is 1 mm, with a total reduction of 5 mm, to obtain a Cu-Ni-Si-Fe alloy strip billet with a thickness of 1 mm. Finally, perform aging treatment, aging at 300 °C for 3 h, and then cool it by water quenching to finally obtain the Cu-Ni-Si-Fe alloy.

[0033] Tensile property tests were carried out on the specimens obtained in Example 1 and Comparative Example 1, and the results are as Figure 4 shown; hardness and conductivity tests were carried out on the specimens, and the results are as Figure 5 shown. The specific data are shown in Table 1.

[0034] Through comparison, it is found that the Cu-Ni-Si-Fe alloy prepared in Example 1 has excellent comprehensive properties, with a hardness of 242 HV, a conductivity of 35 %IACS, a tensile strength of 687 MPa, and an elongation of 9 %, which are significantly higher than those in Comparative Example 1. The key to the performance improvement: The material structure and composition prepared by powder metallurgy in Example 1 are more uniform. At the same time, the application of powder metallurgy technology makes the precipitated phase size fine and uniformly distributed in the matrix.

[0035] Example 2 A method for preparing high-strength and high-conductivity Cu-Ni-Si-Fe alloy based on powder metallurgy technology, and the specific preparation steps are as follows: (1) Preparation of Cu-Ni-Si-Fe alloy powder: Put three materials, namely high-purity electrolytic Cu plate, high-purity electrolytic Ni plate and high-purity electrolytic Si plate, into a vacuum induction melting furnace for melting at 1450 °C to obtain a uniformly mixed Cu-Ni-Si alloy molten metal; slowly add pure Fe powder with a mass fraction of 1 wt% into the molten metal and stir to obtain a uniformly composed Cu-Ni-Si-Fe molten metal. Let the molten metal flow into the atomization chamber through a diversion tube. Under the protection gas of argon, at a pressure of 4 MPa and a flow rate of 450 m 3 / h, a high-speed gas flow has a huge impact on the molten metal, generating strong shear force and impact force, breaking it into filaments or small droplets. These droplets fly downward in the atomization chamber and are quickly cooled to obtain uniformly sized spherical powders of Cu-Ni-Si-Fe alloy; (2) Preparation of Cu-Ni-Si-Fe alloy block: Take 20 g of the Cu-Ni-Si-Fe powder obtained in step (1) and add it to a graphite mold. Through spark plasma sintering, keep it at 850 °C for 10 min, with a heating rate of 100 °C / min. Wait for the temperature to cool below room temperature and then take out the sample to obtain a Cu-Ni-Si-Fe alloy sintered blank with a thickness of 6 mm; (3) Hot working treatment: Perform solution treatment on the Cu-Ni-Si-Fe alloy sintered blank obtained in step (2) at 950 °C for 1.5 h, and then water quench and cool to obtain a supersaturated Cu-Ni-Si-Fe alloy block; then perform rolling treatment at a temperature of 550 °C, with an opening temperature of 550 °C, a holding time of 15 min, 4 rolling passes, a reduction of 1.2 mm per pass, and a total reduction of 4.8 mm to obtain a Cu-Ni-Si-Fe alloy strip blank with a thickness of 1.2 mm. Finally, perform aging treatment at 400 °C for 2 h, and then water quench and cool to finally obtain a Cu-Ni-Si-Fe alloy.

[0036] Perform microscopic morphology analysis on the Cu-Ni-Si-Fe alloy prepared in Example 2, as Figure 3 shown. It can be found from the TEM image that there are three main phases in the alloy, including Cu matrix, precipitation phase and deformation twin. According to the grain size statistics, the average size of the precipitation phase is calculated to be 70 nm. The generation of twins is beneficial to improving the plasticity of the material, and the uniform distribution of these fine precipitates is beneficial to improving the mechanical properties and electrical properties of the material.

[0037] Comparative Example 2 The Cu-Ni-Si-Fe alloy was prepared by melting and casting, and the specific operation steps are as follows: (1) Put three materials, namely high-purity electrolytic Cu plate, high-purity electrolytic Ni plate and industrial-grade polysilicon, into a vacuum induction melting furnace for melting. Then, slowly add pure Fe powder with a mass fraction of 1 wt% into the molten metal and stir to obtain a molten Cu-Ni-Si alloy, which is cast into an alloy ingot with dimensions of 100 mm (length) × 60 mm (width) × 25 mm (thickness); (2) Process the alloy ingot obtained in step (1) into an initial billet with dimensions of 60 mm (length) × 40 mm (width) × 20 mm (thickness). Then, homogenize it at 900 °C for 2 h to obtain a homogeneous block. Roll the homogeneous block at 800 °C for 4 passes, with a reduction of 3.5 mm per pass, to obtain a block with a thickness of 6 mm; (3) Solution-treat the alloy block obtained in step (2) at 950 °C for 1.5 h and cool it by water quenching to obtain a solution-treated block. Then, roll the solution-treated block at 550 °C. The opening temperature is 550 °C, the holding time is 15 min, the number of rolling passes is 4 passes, and the reduction per pass is 1.2 mm, with a total reduction of 4.8 mm, to obtain a Cu-Ni-Si-Fe alloy strip blank with a thickness of 1.2 mm. Finally, perform aging treatment, aging at 400 °C for 2 h, and then cool it by water quenching to finally obtain the Cu-Ni-Si-Fe alloy.

[0038] Tensile property tests were carried out on the specimens obtained in Example 2 and Comparative Example 2, and the results are as Figure 6 shown; hardness and conductivity tests were carried out on the specimens, and the results are as Figure 7 shown. The specific data are shown in Table 1.

[0039] According to Figure 6 , Figure 7 and the comparison of mechanical properties and electrical properties in Table 1, it can be clearly observed that the properties of the Cu-Ni-Si-Fe alloy prepared in Example 2 are much higher than those prepared in Comparative Example 1. The strength is increased by 242 MPa, the hardness is increased by 46 HV, the conductivity is increased by 6 %IACS, and the elongation is increased by 3 %. The main reason for this improvement is also the powder metallurgy preparation technology. Compared with Example 1, the properties of the material prepared in Example 2 are further improved, mainly due to the role played by Fe element. The appropriate content of Fe element promotes the precipitation of the precipitated phase and simultaneously refines the grain size, thereby improving the properties of the material.

[0040] Example 3 A method for preparing high-strength and high-conductivity Cu-Ni-Si-Fe alloy based on powder metallurgy technology, and the specific preparation steps are as follows: (1) Preparation of Cu-Ni-Si-Fe alloy powder: Put three materials, namely high-purity electrolytic Cu plate, high-purity electrolytic Ni plate and high-purity electrolytic Si plate, into a vacuum induction melting furnace for melting at 1500 °C to obtain a uniformly mixed Cu-Ni-Si alloy molten metal; slowly add pure Fe powder with a mass fraction of 1.2 wt% into the molten metal and stir to obtain a uniformly composed Cu-Ni-Si-Fe molten metal. Let the molten metal flow into the atomization chamber through a diversion tube. Under the condition of a protective gas of argon, with a pressure of 5 MPa and a flow rate of 500 m 3 / h, a high-speed gas flow has a huge impact on the molten metal, generating strong shear force and impact force, breaking it into filaments or small droplets. These droplets fly downward in the atomization chamber and are quickly cooled to obtain uniformly sized spherical powders of Cu-Ni-Si-Fe alloy; (2) Preparation of Cu-Ni-Si-Fe alloy block: Take 20 g of the Cu-Ni-Si-Fe powder obtained in step (1) and add it into a graphite mold. Through spark plasma sintering, keep it at 900 °C for 15 min, with a heating rate of 150 °C / min. Wait for the temperature to cool below room temperature and then take out the sample to obtain a Cu-Ni-Si-Fe alloy sintered blank with a thickness of 6 mm; (3) Hot processing treatment: Carry out solution treatment on the Cu-Ni-Si-Fe alloy sintered blank obtained in step (2) at 900 °C for 1 h, and then water quench and cool to obtain a supersaturated Cu-Ni-Si-Fe alloy block; then carry out rolling treatment at a temperature of 600 °C, with an opening temperature of 600 °C, a holding time of 15 min, 3 rolling passes, a reduction of 1.5 mm per pass, and a total reduction of 4.5 mm to obtain a Cu-Ni-Si-Fe alloy strip blank with a thickness of 1.5 mm. Finally, carry out aging treatment at 500 °C for 1 h, and then water quench and cool to finally obtain the Cu-Ni-Si-Fe alloy.

[0041] Comparative Example 3 Prepare Cu-Ni-Si-Fe alloy by melting and casting method, and the specific operation steps are as follows: (1) Put three materials, namely high-purity electrolytic Cu plate, high-purity electrolytic Ni plate and industrial-grade polysilicon, into a vacuum induction melting furnace for melting. Then slowly add pure Fe powder with a mass fraction of 1.2 wt% into the molten metal and stir to obtain a molten Cu-Ni-Si alloy, and pour it into an alloy ingot with dimensions of 100 mm (length) × 60 mm (width) × 25 mm (thickness); (2) The alloy ingot obtained in step (1) was processed into an initial billet with dimensions of 60 mm (length) × 40 mm (width) × 20 mm (thickness), and then homogenized at 900 °C for 2 h to obtain a homogeneous block; the homogeneous block was rolled at 800 °C for 4 passes with a reduction of 3.5 mm per pass to obtain a block with a thickness of 6 mm; (3) The alloy block obtained in step (2) was solution-treated at 900 °C for 1 h and quenched in water to obtain a solution-treated block. Then, the solution-treated block was rolled at 600 °C. The opening temperature was 600 °C, the holding time was 15 min, the number of rolling passes was 3 passes, and the reduction per pass was 1.5 mm, with a total reduction of 4.5 mm to obtain a Cu-Ni-Si-Fe alloy strip billet with a thickness of 1.5 mm; finally, aging treatment was carried out, aging treatment at 500 °C for 1 h, and then quenched in water to finally obtain the Cu-Ni-Si-Fe alloy.

[0042] Tensile property tests were carried out on the specimens obtained in Example 3 and Comparative Example 3, and the results are as Figure 8 shown; hardness and electrical conductivity tests were carried out on the specimens, and the results are as Figure 9 shown. The specific data are shown in Table 1.

[0043] According to Figure 8 , Figure 9 and the comparison of mechanical properties and electrical properties in Table 1, it can be found that the performance of the samples obtained in Example 3 is still higher than that in Comparative Example 3. Similarly, the reason for the performance improvement here also comes from powder metallurgy technology. Compared with Example 2, the performance of the samples in Example 3 has a significant decline, which is attributed to the excessive Fe element promoting the further growth of the precipitation phase, resulting in a certain degree of decline in the comprehensive performance.

[0044] Comparative Example 4 The Cu-Ni-Si alloy was prepared by powder metallurgy technology, and the specific operation steps are as follows: (1) Three materials, high-purity electrolytic Cu plate, high-purity electrolytic Ni plate, and high-purity electrolytic Si plate, were put into a vacuum induction melting furnace for melting at 1450 °C to obtain a uniformly mixed Cu-Ni-Si alloy molten metal; the molten metal was flowed into the atomization chamber through a diversion tube. Under the condition of a protective gas of argon, with a pressure of 4 MPa and a flow rate of 450 m 3 / h, a high-speed gas flow had a huge impact on the molten metal, generating strong shear force and impact force, breaking it into filaments or small droplets. These droplets flew downward in the atomization chamber and were quickly cooled to obtain uniformly sized Cu-Ni-Si alloy spherical powders; (2) Take 20 g of the Cu-Ni-Si powder obtained in step (1) and add it to a graphite mold. Through spark plasma sintering, keep it at 850 °C for 10 min, with a heating rate of 100 °C / min. After the temperature cools below room temperature, take out the sample to obtain a Cu-Ni-Si alloy sintered blank with a thickness of 6 mm; (3) Perform solution treatment on the Cu-Ni-Si alloy sintered blank obtained in step (2) at 950 °C for 1.5 h, then water quench and cool to obtain a supersaturated Cu-Ni-Si alloy block. Then perform rolling treatment at a temperature of 550 °C, with an opening temperature of 550 °C, a holding time of 15 min, 4 rolling passes, and a reduction of 1.2 mm per pass, for a total reduction of 4.8 mm, to obtain a Cu-Ni-Si alloy strip blank with a thickness of 1.2 mm. Finally, perform aging treatment at 400 °C for 2 h, then water quench and cool to finally obtain a Cu-Ni-Si alloy.

[0045] Comparative Example 5 Prepare a Cu-Ni-Si alloy by melting and casting. The specific operation steps are the same as those in Comparative Example 3, except that Fe powder is not added to the molten metal mixture.

[0046] Perform tensile property tests on the specimens obtained in Example 2, Comparative Example 4, and Comparative Example 5. The results are as Figure 10 shown; perform hardness and conductivity tests on the specimens. The results are as Figure 11 shown. The specific data are shown in Table 1.

[0047] According to Figure 10 、 Figure 11 and the comparison of the mechanical properties and electrical properties in Table 1, it can be observed that the comprehensive properties of the Cu-Ni-Si-Fe alloy prepared in Example 2 are the most excellent. Compared with the Cu-Ni-Si alloy prepared by powder metallurgy technology in Comparative Example 4, the reason for the performance improvement is that the introduction of Fe element accelerates the precipitation of the precipitated phase, refines the grains and the precipitated phase, thereby improving the performance. Compared with the Cu-Ni-Si alloy prepared by melting and casting in Comparative Example 5, the performance is further improved, mainly due to the introduction of Fe element and the preparation method of powder metallurgy.

[0048] Table 1 The technical solutions of the present invention are not limited to the above specific implementation cases. Any technical deformation, modification, substitution, and variation carried out according to the technical solutions of the present invention without departing from the spirit and scope protected by the claims of the present invention fall within the protection scope of the present invention.

Claims

1. A method for preparing high-strength and high-conductivity Cu-Ni-Si-Fe alloy based on powder metallurgy technology, characterized in that: (1) Preparation of Cu-Ni-Si-Fe alloy powder: Put three materials, namely high-purity electrolytic Cu plate, high-purity electrolytic Ni plate and high-purity electrolytic Si plate, into a vacuum induction melting furnace for melting to obtain a uniformly mixed Cu-Ni-Si alloy molten metal; slowly add pure Fe powder into the molten metal and stir to obtain a uniformly composed Cu-Ni-Si-Fe molten metal, and let the molten metal flow into the atomization chamber through a diversion tube, and obtain uniformly sized spherical Cu-Ni-Si-Fe alloy powder by gas atomization method; (2) Preparation of Cu-Ni-Si-Fe alloy block: Add the Cu-Ni-Si-Fe powder obtained in step (1) into a graphite mold for densification sintering, take out the sample after the temperature cools below room temperature to obtain a Cu-Ni-Si-Fe alloy sintered blank; (3) Hot working treatment: Perform high-temperature solution treatment on the Cu-Ni-Si-Fe alloy sintered blank obtained in step (2) to obtain a supersaturated Cu-Ni-Si-Fe alloy block; perform multi-pass rolling treatment on it, and finally perform low-temperature aging treatment to obtain a Cu-Ni-Si-Fe alloy material.

2. The method for preparing a high-strength and high-conductivity Cu-Ni-Si-Fe alloy based on powder metallurgy technology according to claim 1, wherein: In step (1), the melting temperature is: 1400 °C to 1500 °C.

3. The method for preparing a high-strength and high-conductivity Cu-Ni-Si-Fe alloy based on powder metallurgy technology according to claim 1, wherein: In step (1), the atomizing gas is high-purity argon, with a pressure of 3 MPa to 5 MPa and a flow rate of 400 m 3 / h to 500 m 3 / h.

4. The method for preparing a high-strength and high-conductivity Cu-Ni-Si-Fe alloy based on powder metallurgy technology according to claim 1, wherein: In step (1), the addition amount of Fe powder is 0.8 wt% to 1.2 wt%.

5. The method for preparing a high-strength and high-conductivity Cu-Ni-Si-Fe alloy based on powder metallurgy technology according to claim 1, characterized in that: In step (2), the sintering temperature is 800 °C to 900 °C, the heating rate is 50 °C / min to 150 °C / min, and the holding time is 5 min to 15 min.

6. The method for preparing a high-strength and high-conductivity Cu-Ni-Si-Fe alloy based on powder metallurgy technology according to claim 1, wherein: In step (3), the temperature of the solution treatment is 900 °C to 1000 °C, the time is 1 h to 2 h, and it is cooled by water quenching.

7. The method for preparing a high-strength and high-conductivity Cu-Ni-Si-Fe alloy based on powder metallurgy technology according to claim 1, characterized in that: In step (3), the temperature of the rolling treatment is 500 °C to 600 °C, the number of rolling passes is 3 to 5 times, and the rolling reduction per pass is 1 mm to 2 mm.

8. A method for preparing a high-strength and high-conductivity Cu-Ni-Si-Fe alloy based on powder metallurgy technology according to claim 1, characterized in that: In step (3), the temperature of the aging treatment is 300 °C to 500 °C, the time of the aging treatment is 1 h to 3 h, and it is cooled by water quenching.

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