Preparation method of high-strength and high-conductivity powder metallurgy copper-nickel-silicon alloy

Abstract

The invention relates to a preparation method of a high-strength and high-conductivity powder metallurgy copper-nickel-silicon alloy, and belongs to the technical field of copper alloys and powder metallurgy materials. S2, powder pressing forming; s3, sintering and densifying; s4, deformation processing treatment; and S5, solid solution and aging treatment. According to the preparation method of the high-strength and high-conductivity powder metallurgy copper-nickel-silicon alloy, 0.01%-2% of the P element is added on the basis of the copper-nickel-silicon alloy, short-range diffusion and uniform distribution of the P element in a copper matrix are achieved through uniform mixing of raw material powder and strict control over the sintering temperature and the heat preservation time, the copper matrix is deoxidized and purified to the maximum extent, oxidation of the Si element is restrained, and the high-strength and high-conductivity powder metallurgy copper-nickel-silicon alloy is obtained. And secondly, high-temperature sintering and deformation processing of the copper-nickel-silicon alloy are combined, the deformation processing temperature after sintering is strictly controlled, processing defects such as cracks, peeling and wrinkles are prevented, and the copper-nickel-silicon alloy has important application prospects in key conductive parts in the electronic information fields such as communication and semiconductors.

Description

Technical Field

[0001] The invention relates to the technical field of copper alloys and powder metallurgy materials, and in particular to a method for preparing a high-strength and high-conductivity powder metallurgy copper-nickel-silicon alloy. Background Art

[0002] Copper-nickel-silicon alloy is widely used in defense and civilian industries due to its high conductivity and high strength, such as lead frames, electrical connectors and connectors. At present, copper-nickel-silicon alloy is mainly manufactured by traditional smelting and casting methods. However, the cast copper-nickel-silicon alloy has problems such as segregation of alloy element components, slow solidification cooling rate resulting in coarse grains, easy formation of columnar crystals, and coarse precipitated phase size. This will reduce the mechanical, conductive and processing properties of the alloy, and it is difficult to fully realize the performance potential of copper-nickel-silicon alloy with both high strength and high conductivity. In addition, some trace Ni and Si elements in the copper matrix are still difficult to precipitate through aging, which will increase electron scattering in the copper matrix, thereby reducing the conductivity of the copper-nickel-silicon alloy.

[0003] Chinese patents CN117867425A and CN202110024381 disclose a preparation method that uses an electromagnetic casting process and adds magnesium, aluminum, rare earth, and zirconium elements to refine the grains of alloy ingots to avoid the generation of columnar crystals and segregation-induced hot rolling cracking. This method has a complex smelting and casting process and has high requirements for equipment. In addition, the addition of other alloying elements may increase costs and introduce impurities, which may lead to reduced conductivity.

[0004] At the same time, Chinese patent CN115627380A discloses a preparation method for controlling the size and distribution of the precipitated phase by designing the nickel-silicon composition of the molten copper-nickel-silicon alloy. The alloy material is obtained through processes such as smelting and casting, hot rolling, solution treatment, multiple deformation and aging treatment. The preparation process has many steps, a long time, high energy consumption, and low efficiency. In addition, the accuracy of the composition control is difficult to control. The room temperature tensile strength, elongation, conductivity and other properties of the obtained alloy are not comprehensively improved.

[0005] In summary, Chinese patents CN117265313A and CN111074092A disclose the preparation of copper-nickel-silicon alloys with uniform composition, precipitation phase and fine grains by powder metallurgy using copper-nickel-silicon alloy powder or element mixed powder. Although this method solves the problems of composition segregation and coarse grains, some solid-dissolved nickel and silicon atoms still exist in the copper matrix and are difficult to completely precipitate, which weakens the precipitation strengthening effect of the alloy elements and also reduces the conductivity of the alloy. Therefore, this application proposes a preparation method of high-strength and high-conductivity powder metallurgy copper-nickel-silicon alloy to solve the above problems. Summary of the Invention

[0006] In response to the shortcomings of the existing technology, the present invention provides a method for preparing a high-strength and high-conductivity powder metallurgy copper-nickel-silicon alloy, which has the advantages of uniform composition without segregation, small grain size, high density and good processing performance. It solves the problems of copper-nickel-silicon alloy prepared by traditional smelting and casting processes, such as composition segregation, coarse grain size, poor processing performance, difficulty in completely precipitating trace solid-dissolved Ni and Si atoms in the matrix, and difficulty in achieving both high strength and high conductivity.

[0007] To achieve the above object, the present invention provides the following technical solution: a method for preparing a high-strength and high-conductivity powder metallurgy copper-nickel-silicon alloy, comprising the following steps:

[0008] S1: Copper-nickel-silicon alloy powder and phosphorus-containing powder are mixed in a mixer according to a certain ratio to obtain a mixed powder;

[0009] S2: The mixed powder in step S1 is placed in an elastic rubber bag and pressed in a cold isostatic press to obtain a green body A; or the mixed powder in step S1 is pressed into a steel mold to obtain a green body B;

[0010] S3: placing the formed green body A or the formed green body B in step S2 in a vacuum sintering furnace or an atmosphere protection furnace for sintering to obtain a copper-nickel-silicon alloy sintered ingot;

[0011] S4: taking out the copper-nickel-silicon alloy sintered ingot in step S3, and hot-extruding and drawing it to obtain rods and wires, or hot-rolling and cold-rolling it to obtain plates and strips;

[0012] S5: The wire or strip material after cold deformation in step S4 is subjected to online solution treatment, and then placed in a protective environment of hydrogen atmosphere for aging heat treatment, followed by low-temperature tension annealing, and finally cleaned to obtain a high-strength and high-conductivity powder metallurgy copper-nickel-silicon alloy material.

[0013] Furthermore, the copper-nickel-silicon alloy powder described in step S1 is at least one of mechanically alloyed alloy powder, water-atomized alloy powder, gas-atomized alloy powder and water-gas combined atomized alloy powder, and has an average particle size of 2-120 μm; the phosphorus-containing powder described in step S1 is at least one of copper-phosphorus alloy powder and elemental phosphorus powder, and has an average particle size of 3-80 μm.

[0014] Furthermore, in the mixed powder A in step S1, the mass fraction of Ni is 0.3-5%, the mass fraction of Si is 0.1-1%, the mass fraction of P is 0.01-2%, and the rest is copper element, wherein the mass ratio of Ni to Si is 3:1-5:1.

[0015] Furthermore, the pressure of the cold isostatic pressing in step S2 is 40-600 MPa, the pressure of the compression molding is 100-700 MPa, and the holding time is 5-250 s.

[0016] Furthermore, the gas in the atmosphere protection furnace in step S3 is at least one of hydrogen, nitrogen, argon, methane, acetylene and carbon monoxide, and the sintering temperature is 750-1050° C., and the holding time is 1-5 hours.

[0017] Furthermore, the vacuum degree of the vacuum sintering furnace in step S3 is 10 -1 -10 -3 Pa, the sintering temperature is 750-1050℃, and the holding time is 2-6h.

[0018] Furthermore, the hot extrusion temperature in step S4 is 450-950°C, and the hot rolling temperature is 600-950°C.

[0019] Furthermore, the solution treatment temperature in step S5 is 750-1000° C. and the time is 1-4 hours.

[0020] Furthermore, the aging treatment temperature in step S5 is 300-700° C., and the aging time is 1-15 hours.

[0021] Furthermore, the low-temperature tension annealing temperature in step S5 is 150-350° C., and the annealing time is 1-6 hours.

[0022] Compared with the existing technology, the technical solution of this application has the following beneficial effects:

[0023] 1. The preparation method of the high-strength and high-conductivity powder metallurgy copper-nickel-silicon alloy is to add 0.01-2% P element by mass to the copper-nickel-silicon alloy. By uniformly mixing the raw material powders and strictly controlling the sintering temperature and holding time, the short-range diffusion and uniform distribution of the P element in the copper matrix are achieved, the copper matrix is deoxidized and purified to the maximum extent, the oxidation of the Si element is inhibited, and the strength, conductivity and processing properties of the alloy material are improved. Secondly, the high-temperature sintering of the copper-nickel-silicon alloy is combined with deformation processing, and the deformation processing temperature after sintering is strictly controlled to prevent the occurrence of processing defects such as cracks, peeling, and wrinkles; at the same time, the solid solution and aging heat treatment are optimized. The reasonable process parameters, including temperature and time, can reduce the residual nickel content in the copper matrix and ensure that it is finally transformed into Ni3P precipitation phase, which can not only strengthen the copper alloy matrix to a certain extent, but also effectively improve the conductivity of the copper-nickel-silicon alloy; the low-temperature tension annealing process can eliminate some movable dislocations inside the alloy and leave immovable dislocations, which can improve the stress relaxation performance of the alloy to a certain extent. The prepared copper-nickel-silicon alloy ingot has low oxygen content, high sintering density, uniform composition without segregation, sufficient precipitation of Ni and Si elements, small grain size, excellent processing performance, and has high strength, high elongation and high conductivity.

[0024] 2. The preparation method of this high-strength and high-conductivity powder metallurgy copper-nickel-silicon alloy achieves a steady improvement in the performance of copper-based alloy products through the organic combination of powder metallurgy, deformation processing and heat treatment processes. Compared with traditional melting and casting methods, the copper-nickel-silicon alloy produced by powder metallurgy has a 6-8% increase in strength, a 10-28% increase in conductivity, a 25-35% reduction in cost, and a 30-40% shortened production cycle. It can achieve continuous large-scale production and has important application prospects in key conductive components in electronic information fields such as communications and semiconductors. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Flow chart of the alloy preparation method of the present invention. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0027] Example 1

[0028] A method for preparing a high-strength and high-conductivity powder metallurgy copper-nickel-silicon alloy, wherein the alloy material is made of the following components by weight percentage: Ni 0.3%, Si 0.1%, P 0.01%, and the balance Cu, with an element composition ratio of 3:1:0.1, as shown in Table 1.

[0029] Among them, the preparation method of high-strength and high-conductivity powder metallurgy copper-nickel-silicon alloy is as follows:

[0030] S1: Weigh 16081.14 g of aerosolized copper-nickel-silicon alloy powder with an average particle size of 2 μm and 1.61 g of red phosphorus powder with an average particle size of 3 μm, then put them into a V-type mixer for mixing. The mixing time is 2.5 hours. After the mixing is completed, a uniformly mixed alloy powder is obtained.

[0031] S2: The mixed powder is placed in a silica gel bag with an inner cavity size of φ95×300mm. After packaging, it is placed in a cold isostatic press for pressing. The cold isostatic pressing pressure is 40MPa and the holding time is 250s. After pressing, a rod blank of φ88×281mm is obtained.

[0032] S3: The green bar formed by cold isostatic pressing is placed in a vacuum sintering furnace. A crucible containing 1 kg of pure titanium powder is placed in the furnace. After vacuuming, vacuum sintering is carried out with a vacuum degree of 10-1 Pa, a sintering temperature of 750°C, and a holding time of 6 hours. After sintering, a copper-nickel-silicon alloy sintered bar blank is obtained.

[0033] S4: The sintered rod blank is subjected to hot extrusion treatment at a temperature of 450°C. The diameter of the rod after extrusion is 15 mm. The surface oxide scale is then removed and the rod is drawn into an alloy wire with a diameter of 1 mm.

[0034] S5: The copper-nickel-silicon alloy wire is placed at 750°C for solution treatment with a solution time of 4 hours; then it is subjected to aging heat treatment at 700°C for 1 hour; finally, it is subjected to low-temperature tension annealing at 350°C for 1 hour at a tension of 30 MPa, ultimately obtaining a copper-nickel-silicon alloy conductive wire with a diameter of 1 mm, in which the residual nickel content of the solid solution in the copper matrix is 0.002%, the Ni3P precipitation phase content is 0.05%, the oxygen content is 950 ppm, the average grain size is about 2.2 μm, the density is 99.8%, and the strength and conductivity test results are: hardness 230 HV, tensile strength 695 MPa, and conductivity 68% IACS.

[0035] It should be noted that in Example 1, a high-strength and high-conductivity copper-nickel-silicon alloy was prepared by powder metallurgy, wherein the composition of the alloy is Ni0.3%, Si0.1%, P0.01% by weight, and the balance is Cu. Atomized copper-nickel-silicon alloy powder and red phosphorus powder are used as raw materials. After mixing, cold isostatic pressing, vacuum sintering, hot extrusion drawing, and solution aging heat treatment, the final alloy wire has excellent properties of hardness 230HV, tensile strength 695MPa, and conductivity 68%IACS, and has low oxygen content, fine grain size, and high density, showing good comprehensive performance.

[0036] Example 2

[0037] A method for preparing a high-strength and high-conductivity powder metallurgy copper-nickel-silicon alloy, wherein the alloy material is made of the following components by weight percentage: Ni 1%, Si 0.25%, P 0.1%, and the balance Cu, with an element composition ratio of 4:1:0.4, as shown in Table 1.

[0038] Among them, the preparation method of high-strength and high-conductivity powder metallurgy copper-nickel-silicon alloy is as follows:

[0039] S1: Weigh 5280.42 g of water-atomized copper-nickel-silicon alloy powder with an average particle size of 30 μm and 5.29 g of red phosphorus powder with an average particle size of 15 μm, then put them into a V-type mixer for mixing. The mixing time is 2.5 hours. After the mixing is completed, a uniformly mixed alloy powder is obtained.

[0040] S2: The mixed powder is placed in a silica gel bag with an inner cavity size of 200×150×30 mm. After packaging, the bag is placed in a cold isostatic press for pressing. The cold isostatic pressing pressure is 300 MPa and the holding time is 150 s. After pressing, a 187×136×22 mm plate green body is obtained.

[0041] S3: The green sheet formed by cold isostatic pressing is placed in a vacuum sintering furnace. A crucible containing 1 kg of pure titanium powder is placed in the furnace. After vacuuming, vacuum sintering is carried out with a vacuum degree of 10-2 Pa, a sintering temperature of 900°C, and a holding time of 4 hours. After sintering, a copper-nickel-silicon alloy sintered sheet is obtained.

[0042] S4: The sintered slab is hot rolled at a temperature of 600° C. The thickness of the slab after hot rolling is 12 mm. The surface oxide scale is then removed and the slab is cold rolled multiple times to form an alloy strip with a thickness of 0.5 mm.

[0043] S5: The copper-nickel-silicon alloy strip is placed at 850°C for solution treatment with a solution time of 3 hours; then it is aged at 550°C for 5 hours; finally, it is subjected to low-temperature tension annealing at 300°C for 3 hours at a tension of 50 MPa, ultimately obtaining a copper-nickel-silicon alloy strip with a thickness of 0.5 mm, in which the residual nickel content of the solid solution in the copper matrix is 0.005%, the Ni3P precipitation phase content is 0.1%, the oxygen content is 1300 ppm, the average grain size is about 4.7 μm, the density is 99.8%, and the strength and conductivity test results are: hardness 254 HV, tensile strength 760 MPa, and conductivity 63% IACS.

[0044] It should be noted that Example 2 uses water-atomized copper-nickel-silicon alloy powder and red phosphorus powder as raw materials to prepare a high-strength and high-conductivity copper-nickel-silicon alloy with a composition of Ni 1%, Si 0.25%, and P 0.1% by weight. Through mixing, cold isostatic pressing, vacuum sintering, hot rolling and cold rolling, and solution aging heat treatment, the obtained alloy strip has a hardness of 254HV, a tensile strength of 760MPa, and a conductivity of 63%IACS. It has the characteristics of uniform composition, fine grains, and excellent processing performance. It has both high strength and high conductivity and is suitable for key conductive components in the electronic information field.

[0045] Example 3

[0046] A method for preparing a high-strength and high-conductivity powder metallurgy copper-nickel-silicon alloy, wherein the alloy material is made of the following components by weight percentage: Ni 2.5%, Si 0.5%, P 1.0%, and the balance Cu, with an element composition ratio of 5:1:2, as shown in Table 1.

[0047] Among them, the preparation method of high-strength and high-conductivity powder metallurgy copper-nickel-silicon alloy is as follows:

[0048] S1: Weigh 1882.57 g of water-vapor atomized copper-nickel-silicon alloy powder with an average particle size of 80 μm and 19.02 g of red phosphorus powder with an average particle size of 60 μm, then put them into a V-type mixer for mixing. The mixing time is 2.5 hours, and after the mixing is completed, a uniformly mixed alloy powder is obtained.

[0049] S2: The mixed powder is placed in a silica gel bag with an inner cavity size of 150×100×25 mm. After packaging, it is placed in a cold isostatic press for pressing. The cold isostatic pressing pressure is 600 MPa and the holding time is 50 s. After pressing, a 141×86×18 mm plate green body is obtained.

[0050] S3: Place the green sheet formed by cold isostatic pressing into a vacuum sintering furnace. A crucible containing 1 kg of pure titanium powder is placed in the furnace. After vacuuming, vacuum sintering is performed with a vacuum degree of 10-3 Pa, a sintering temperature of 1050°C, and a holding time of 2 hours. After sintering, a copper-nickel-silicon alloy sintered sheet is obtained.

[0051] S4: The sintered slab is hot rolled at a temperature of 850° C. The thickness of the bar after hot rolling is 10 mm. The surface oxide scale is then removed and the bar is cold rolled multiple times to form an alloy plate with a thickness of 1 mm.

[0052] S5: The copper-nickel-silicon alloy plate is placed at 950°C for solution treatment with a solution time of 2 hours; then it is aged at 400°C for 10 hours; finally, it is subjected to low-temperature tension annealing at 200°C for 5 hours at a tension of 70 MPa, ultimately obtaining a copper-nickel-silicon alloy plate with a thickness of 1 mm, wherein the residual nickel content of the solid solution in the copper matrix is 0.006%, the Ni3P precipitation phase content is 0.2%, the oxygen content is 1000 ppm, the average grain size is about 6.8 μm, the density is 99.9%, and the strength and conductivity test results are: hardness 278 HV, tensile strength 783 MPa, and conductivity 54% IACS.

[0053] It should be noted that in Example 3, a high-strength and high-conductivity copper-nickel-silicon alloy with a weight percentage of 2.5% Ni, 0.5% Si, and 1.0% P was prepared using water-vapor atomized copper-nickel-silicon alloy powder and red phosphorus powder as raw materials. After mixing, cold isostatic pressing, vacuum sintering, hot and cold rolling, and solution aging heat treatment, the resulting alloy sheet exhibited a hardness of 278 HV, a tensile strength of 783 MPa, and a conductivity of 54% IACS. This alloy exhibits high strength and conductivity, low oxygen content, high density, and a moderate grain size, demonstrating excellent overall performance and meeting the needs of specific industrial applications.

[0054] The working principle of the above embodiment is as follows: copper-nickel-silicon alloy powder is used as raw material, a certain amount of phosphorus is added, and after the mixture is obtained into a uniform powder, it is formed and sintered to obtain a dense ingot, which is then deformed and subjected to solid solution aging heat treatment to obtain a copper-nickel-silicon alloy plate or wire. During the high-temperature sintering process, the phosphorus element in the phosphorus-containing powder is easily diffused in the copper matrix, and the content that can be added is relatively high, and there is no solid-liquid phase transition. The phosphorus element will not cause the problem of intergranular brittleness caused by the grain boundary segregation of trace elements formed in the traditional molten casting liquid phase solidification process. More importantly, Yes, the addition of phosphorus can play a role in deoxidation and purification, reduce the sintering temperature, and precipitate the residual nickel atoms dissolved in the copper matrix as nickel-phosphorus compounds (Ni3P). These precipitated fine nickel-phosphorus compounds hinder dislocation slip, effectively inhibit the growth of Ni2Si particles during the aging process, refine the grains, and increase the precipitation rate of Ni2Si phase. At the same time, it reduces the scattering effect of residual solid-solution nickel atoms on electrons, further strengthens the matrix, thereby improving the strength and conductivity of the copper-nickel-silicon alloy at the same time, turning the phosphorus element from a harm to a benefit.

[0055] It can be seen that the core of the working principle of the present invention is to add an appropriate amount of phosphorus to the copper-nickel-silicon alloy powder, and prepare a high-performance copper-nickel-silicon alloy material through processes such as mixing, forming, sintering, deformation processing and solution aging heat treatment. During the sintering process, phosphorus diffuses in the copper matrix, avoiding the intergranular brittleness problem caused by grain boundary segregation in the traditional melting and casting process. The addition of phosphorus has multiple advantages: deoxidation and purification of the copper matrix, lowering the sintering temperature, and promoting the precipitation of residual nickel in the form of nickel-phosphorus compounds (Ni3P). These fine Ni3P particles hinder dislocation slip, inhibit the growth of Ni2Si particles, refine the grains, and increase the precipitation rate of the Ni2Si phase. At the same time, the scattering effect of residual nickel atoms on electrons is reduced, the matrix is strengthened, thereby improving the strength and conductivity of the alloy, and realizing the beneficial utilization of the phosphorus element.

[0056] Comparative Example 1

[0057] The preparation processes of Comparative Example 1, such as pressing and sintering, are the same as those of Example 1, except that the composition of the copper-nickel-silicon alloy is different, as shown in Table 1.

[0058] The alloy material is made of the following components by weight: 0.6% Ni, 0.2% Si, 0.05% P, and the remainder Cu, with an element composition ratio of 3:1:0.25.

[0059] The differences in methods are as follows:

[0060] In S1, 15130.36 g of mechanically alloyed copper-nickel-silicon alloy powder with an average particle size of 10 μm and 108.85 g of copper-phosphorus alloy powder with an average particle size of 8 μm (wherein the P content is 7 wt.%) were weighed.

[0061] In S2, the mixed alloy powder is pressed into a rod green body of φ85×280 mm by a cold isostatic press.

[0062] In S4, the rod diameter after hot extrusion is 12 mm, and then the surface oxide scale is removed and drawn into an alloy wire with a diameter of 1 mm;

[0063] In S5, after solution treatment, aging treatment and low-temperature tension annealing, a copper-nickel-silicon alloy conductive wire with a diameter of 1 mm was finally obtained, in which the residual nickel content of the solid solution in the copper matrix was 0.003%, the Ni 3P precipitation phase content was 0.08%, the oxygen content was 1800 ppm, the average grain size was about 1.8 μm, the density was 99.8%, and the strength and conductivity test results were: hardness 216 HV, tensile strength 662 MPa, and conductivity 52% IACS.

[0064] It should be noted that Comparative Example 1 differs from Example 1 in composition. Mechanically alloyed copper-nickel-silicon alloy powder and copper-phosphorus alloy powder were used as raw materials to prepare an alloy with a weight percentage of 0.6% Ni, 0.2% Si, and 0.05% P. After cold isostatic pressing, vacuum sintering, hot extrusion drawing, and solution aging heat treatment, the resulting alloy wire exhibited a hardness of 216 HV, a tensile strength of 662 MPa, and a conductivity of 52% IACS. Compared to Example 1, its strength and conductivity were lower, and its oxygen content was higher, demonstrating that alloy composition significantly influences performance.

[0065] Comparative Example 2

[0066] The alloy composition of Comparative Example 2 is the same as that of Example 2, except that the parameters in the preparation process such as pressing and sintering of the alloy powder are different.

[0067] The differences in methods are as follows:

[0068] In S2, the molding pressure is 100 MPa, the holding time is 200 s, and a rod green body of φ89×283 mm is obtained after the pressing is completed.

[0069] In S3, sintering is carried out in a hydrogen atmosphere furnace, hydrogen is continuously introduced into the furnace, the sintering temperature is 750°C, and the holding time is 5h.

[0070] In S4, the hot extrusion temperature is 950°C, and the diameter of the rod after extrusion is 15 mm. The surface oxide scale is then removed and the rod is drawn into an alloy wire with a diameter of 1 mm.

[0071] In S5, solution treatment is first carried out at 800°C for 3 hours; then aging heat treatment is carried out at 600°C for 3 hours; finally, low-temperature tension annealing is carried out at 300°C for 2 hours and a tension of 40 MPa, finally obtaining a copper-nickel-silicon alloy conductive wire with a diameter of 1 mm, in which the residual nickel content of the solid solution in the copper matrix is 0.002%, the Ni3P precipitation phase content is 0.05%, the oxygen content is 1600 ppm, the average grain size is about 2.5 μm, the density is 99.8%, and the strength and conductivity test results are: hardness 237 HV, tensile strength 714 MPa, and conductivity 64% IACS.

[0072] It should be noted that Comparative Example 2 uses the same ingredients as Example 2, but differs in the preparation parameters. Using mechanically alloyed copper-nickel-silicon alloy powder and copper-phosphorus alloy powder as raw materials, and undergoing compression molding, hydrogen atmosphere sintering, hot extrusion drawing, and solution aging heat treatment, the resulting alloy wire exhibits a hardness of 237 HV, a tensile strength of 714 MPa, and a conductivity of 64% IACS. These performance characteristics are slightly lower than those of Example 2, demonstrating the significant influence of preparation process parameters on alloy properties.

[0073] Comparative Example 3

[0074] The preparation process of Comparative Example 3, such as pressing and sintering, is the same as that of Example 2, except that the composition of the copper-nickel-silicon alloy is different, as shown in Table 1.

[0075] The alloy material is made of the following components by weight: 2% Ni, 0.5% Si, 0.5% P, and the remainder Cu, with an element composition ratio of 4:1:1.

[0076] The differences in methods are as follows:

[0077] In S1, 5097.72 g of mechanically alloyed copper-nickel-silicon alloy powder with an average particle size of 50 μm and 392.13 g of copper-phosphorus alloy powder (P content of 7 wt.%) with an average particle size of 30 μm were weighed.

[0078] In S2, the mixed alloy powder was pressed into a green plate of 185×135×20 mm by a cold isostatic press.

[0079] In S4, the plate is hot-rolled to a thickness of 10 mm, and then subjected to surface oxide scale removal and cold-rolled to an alloy strip with a thickness of 0.5 mm.

[0080] In S5, after solution treatment, aging treatment and low-temperature tension annealing, a copper-nickel-silicon alloy strip with a thickness of 0.5 mm was finally obtained, in which the residual nickel content of the solid solution in the copper matrix was 0.004%, the Ni3P precipitation phase content was 0.25%, the oxygen content was 1300 ppm, the average grain size was about 4.3 μm, the density was 99.9%, and the strength and conductivity test results were: hardness 242 HV, tensile strength 736 MPa, and conductivity 59% IACS.

[0081] It should be noted that Comparative Example 3 differs from Example 2 in composition. Mechanically alloyed copper-nickel-silicon alloy powder and copper-phosphorus alloy powder were used as raw materials to prepare an alloy with a weight percentage of 2% Ni, 0.5% Si, and 0.5% P. After cold isostatic pressing, vacuum sintering, hot and cold rolling, and solution aging heat treatment, the resulting alloy strip exhibited a hardness of 242 HV, a tensile strength of 736 MPa, and a conductivity of 59% IACS. These performance differences compared to Example 2 demonstrate that changes in alloy composition can affect final performance.

[0082] Comparative Example 4

[0083] The alloy composition of Comparative Example 4 is the same as that of Example 2, except that the parameters in the preparation process such as pressing and sintering of the alloy powder are different.

[0084] The differences in methods are as follows:

[0085] In S2, the molding pressure is 400 MPa, the holding time is 100 s, and a plate green body of 188×136×20 mm is obtained after the pressing is completed.

[0086] In S3, sintering is carried out in a hydrogen atmosphere furnace, hydrogen is continuously introduced into the furnace, the sintering temperature is 900°C, and the holding time is 3h.

[0087] In S4, the hot rolling temperature is 750° C., and the thickness of the plate after hot rolling is 10 mm. Subsequently, the surface oxide scale is removed and the plate is cold rolled to obtain an alloy strip with a thickness of 0.5 mm.

[0088] In S5, solution treatment is first carried out at 900°C for 2 hours; then aging heat treatment is carried out at 450°C for 7 hours; finally, low-temperature tension annealing is carried out at 250°C for 4 hours and a tension of 60 MPa, finally obtaining a copper-nickel-silicon alloy strip with a thickness of 0.5 mm, in which the residual nickel content of the solid solution in the copper matrix is 0.004%, the Ni3P precipitation phase content is 0.1%, the oxygen content is 1500 ppm, the average grain size is about 3.9 μm, the density is 99.8%, and the strength and conductivity test results are: hardness 252 HV, tensile strength 755 MPa, and conductivity 60% IACS.

[0089] It should be noted that Comparative Example 4 shares the same ingredients as Example 2, but differs in the parameters used during the preparation process. Using mechanically alloyed copper-nickel-silicon alloy powder and copper-phosphorus alloy powder as raw materials, and undergoing processes including compression molding, hydrogen atmosphere sintering, hot and cold rolling, and solution aging heat treatment, the resulting alloy strip exhibits a hardness of 252 HV, a tensile strength of 755 MPa, and a conductivity of 60% IACS. These properties differ slightly from those of Example 2, demonstrating that preparation process parameters significantly influence alloy properties and require strict control for optimal performance.

[0090] Comparative Example 5

[0091] The preparation process of Comparative Example 5, such as pressing and sintering, is the same as that of Example 3, except that the composition of the copper-nickel-silicon alloy is different, as shown in Table 1.

[0092] The alloy material is made of the following components by weight: 5% Ni, 1% Si, 2% P, and the remainder Cu, with an element composition ratio of 5:1:2.

[0093] The differences in methods are as follows:

[0094] In S1, 1806.68 g of mechanically alloyed copper-nickel-silicon alloy powder with an average particle size of 120 μm and 722.67 g of copper-phosphorus alloy powder (P content of 7 wt.%) with an average particle size of 80 μm were weighed.

[0095] In S2, the mixed alloy powder was pressed into a green plate of 138×85×16 mm by a cold isostatic press.

[0096] In S4, the plate thickness after hot rolling is 10 mm, and then the surface oxide scale is removed and the plate is cold rolled to a thickness of 1 mm.

[0097] In S5, after solution treatment, aging treatment and low-temperature tension annealing, a copper-nickel-silicon alloy plate with a thickness of 1 mm was finally obtained, in which the residual nickel content of the solid solution in the copper matrix was 0.008%, the Ni3P precipitation phase content was 0.4%, the oxygen content was 950 ppm, the average grain size was about 6.3 μm, the density was 99.9%, and the strength and conductivity test results were: hardness 293 HV, tensile strength 954 MPa, and conductivity 48% IACS.

[0098] It should be noted that the composition of Comparative Example 5 is different from that of Example 3. Mechanically alloyed copper-nickel-silicon alloy powder and copper-phosphorus alloy powder are used as raw materials to prepare an alloy with a composition of Ni5%, Si 1%, and P2% by weight. After cold isostatic pressing, vacuum sintering, hot rolling and cold rolling, and solution aging heat treatment, the obtained alloy plate has a hardness of 293HV, a tensile strength of 954MPa, and a conductivity of 48%IACS. Compared with Example 3, its conductivity is lower, indicating that excessively high alloy element content may have an adverse effect on the conductive properties.

[0099] Comparative Example 6

[0100] The alloy composition of Comparative Example 6 is the same as that of Example 3, except that the parameters in the preparation process such as pressing and sintering of the alloy powder are different.

[0101] The differences in methods are as follows:

[0102] In S2, the molding pressure is 700 MPa, the holding time is 5 s, and a green sheet of 142×84×16 mm is obtained after the molding is completed.

[0103] In S3, sintering is carried out in a hydrogen atmosphere furnace, hydrogen is continuously introduced into the furnace, the sintering temperature is 1050°C, and the holding time is 1h.

[0104] In S4, the hot rolling temperature is 950° C., and the thickness of the plate after hot rolling is 8 mm. Subsequently, the surface oxide scale is removed and the plate is cold rolled to a thickness of 1 mm.

[0105] In S5, solution treatment is first carried out at 1000°C for 1 hour; then aging heat treatment is carried out at 300°C for 15 hours; finally, low-temperature tension annealing is carried out at 150°C for 6 hours at a tension of 80 MPa, ultimately obtaining a copper-nickel-silicon alloy sheet with a thickness of 1 mm, in which the residual nickel content of the solid solution in the copper matrix is 0.006%, the Ni3P precipitation phase content is 0.2%, the oxygen content is 1200 ppm, the average grain size is about 7.4 μm, the density is 99.8%, and the strength and conductivity test results are: hardness 276 HV, tensile strength 791 MPa, and conductivity 52% IACS.

[0106] It should be noted that Comparative Example 6 uses the same ingredients as Example 3, but differs in the parameters used during the preparation process. Using mechanically alloyed copper-nickel-silicon alloy powder and copper-phosphorus alloy powder as raw materials, and undergoing processes such as compression molding, hydrogen atmosphere sintering, hot and cold rolling, and solution aging heat treatment, the resulting alloy sheet exhibits a hardness of 276 HV, a tensile strength of 791 MPa, and a conductivity of 52% IACS. These performance differences compared to Example 3 demonstrate the significant influence of preparation process parameters on alloy properties, requiring optimization to achieve optimal performance.

[0107] The alloy compositions, hardness, tensile strength and electrical conductivity of Examples 1-3 and Comparative Examples 1-6 are listed in Table 1:

[0108] Table 1 Composition, hardness, strength and conductivity of different copper-nickel-silicon alloys

[0109] Ni (wt.%) Si (wt.%) P (wt.%) Average grain size (μm) Hardness (HV) Tensile strength (MPa) Electrical conductivity (IACS) Example 1 0.30 0.10 0.01 2.2 230 695 68％ Example 2 2.00 0.50 0.1 4.7 254 760 63％ Example 3 2.50 0.50 1.00 6.8 278 783 54％ Comparative Example 1 0.60 0.20 0.05 1.8 216 662 52％ Comparative Example 2 0.30 0.10 0.01 2.5 237 714 64％ Comparative Example 3 1.00 0.25 0.5 4.3 242 736 59％ Comparative Example 4 1.00 0.25 0.1 3.9 252 755 60％ Comparative Example 5 5.00 1.00 2.00 6.3 293 954 48％ Comparative Example 6 2.50 0.50 1.00 7.4 276 791 52％

[0110] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0111] While the embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that various changes, modifications, substitutions, and alterations can be made to the embodiments without departing from the principles and spirit of the invention.

Claims

1. A method for preparing a high-strength and high-conductivity powder metallurgy copper-nickel-silicon alloy, characterized in that: The following steps are involved: S1: Copper-nickel-silicon alloy powder and phosphorus-containing powder are mixed in a mixer according to a certain ratio to obtain a mixed powder; S2: The mixed powder in step S1 is placed in an elastic rubber bag and pressed in a cold isostatic press to obtain a green body A; or the mixed powder in step S1 is pressed into a steel mold to obtain a green body B; S3: placing the formed green body A or the formed green body B in step S2 in a vacuum sintering furnace or an atmosphere protection furnace for sintering to obtain a copper-nickel-silicon alloy sintered ingot; S4: taking out the copper-nickel-silicon alloy sintered ingot in step S3, and hot-extruding and drawing it to obtain rods and wires, or hot-rolling and cold-rolling it to obtain plates and strips; S5: The wire or strip material after cold deformation in step S4 is subjected to online solution treatment, and then placed in a protective environment of hydrogen atmosphere for aging heat treatment, followed by low-temperature tension annealing, and finally cleaned to obtain a high-strength and high-conductivity powder metallurgy copper-nickel-silicon alloy material.

2. The method for preparing a high-strength and high-conductivity powder metallurgy copper-nickel-silicon alloy according to claim 1, characterized in that: The copper-nickel-silicon alloy powder described in step S1 is at least one of mechanical alloying alloy powder, water atomized alloy powder, gas atomized alloy powder and water-gas combined atomized alloy powder, and has an average particle size of 2-120 μm; the phosphorus-containing powder described in step S1 is at least one of copper-phosphorus alloy powder and elemental phosphorus powder, and has an average particle size of 3-80 μm.

3. The method for preparing a high-strength and high-conductivity powder metallurgy copper-nickel-silicon alloy according to claim 1, characterized in that: In the mixed powder A in step S1, the mass fraction of Ni is 0.3-5%, the mass fraction of Si is 0.1-1%, the mass fraction of P is 0.01-2%, and the rest is copper element, wherein the mass ratio of Ni to Si is 3:1-5:

1.

4. The method for preparing a high-strength and high-conductivity powder metallurgy copper-nickel-silicon alloy according to claim 1, wherein: The pressure of the cold isostatic pressing in step S2 is 40-600 MPa, the pressure of the compression molding is 100-700 MPa, and the holding time is 5-250 s.

5. The method for preparing a high-strength and high-conductivity powder metallurgy copper-nickel-silicon alloy according to claim 1, characterized in that: The gas in the atmosphere protection furnace in step S3 is at least one of hydrogen, nitrogen, argon, methane, acetylene and carbon monoxide, and the sintering temperature is 750-1050° C., and the holding time is 1-5 hours.

6. The method for preparing a high-strength and high-conductivity powder metallurgy copper-nickel-silicon alloy according to claim 1, characterized in that: The vacuum degree of the vacuum sintering furnace in step S3 is 10 -1 -10 -3 Pa, the sintering temperature is 750-1050℃, and the holding time is 2-6h.

7. The method for preparing a high-strength and high-conductivity powder metallurgy copper-nickel-silicon alloy according to claim 1, characterized in that: The hot extrusion temperature in step S4 is 450-950°C, and the hot rolling temperature is 600-950°C.

8. The method for preparing a high-strength and high-conductivity powder metallurgy copper-nickel-silicon alloy according to claim 1, characterized in that: The solution treatment temperature in step S5 is 750-1000° C. and the time is 1-4 hours.

9. The method for preparing a high-strength and high-conductivity powder metallurgy copper-nickel-silicon alloy according to claim 1, characterized in that: The aging treatment temperature in step S5 is 300-700° C., and the aging time is 1-15 hours.

10. The method for preparing a high-strength and high-conductivity powder metallurgy copper-nickel-silicon alloy according to claim 1, characterized in that: The low-temperature tension annealing temperature in step S5 is 150-350° C., and the annealing time is 1-6 hours.

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