Preparation method and application of composite metal wire or strip

Abstract

The invention provides a preparation method and application of a composite metal wire or strip, and relates to the technical field of composite metal processing. Specifically, the method comprises the following steps: preparing a metal tube, and inserting a metal column with the same height into the metal tube; the assembled composite blank is subjected to rotary swaging; the blank obtained after rotary swaging is subjected to annealing rolling, and a composite metal strip is obtained; or the blank obtained after rotary swaging is subjected to wire drawing, and the composite metal wire is obtained; and for the strip, the perimeter of the cross section, the diameter after rotary swaging and the first-pass rolling reduction of annealing rolling meet a specific proportional relation. The method can be used for preparing a composite wire for bonding or a sandwich-structure strip for brazing, can effectively overcome the defects that conventional compounding modes such as hot rolling compounding, diffusion compounding, extrusion compounding and explosive compounding cannot give consideration to the aspects of finished product quality, production efficiency, cost and the like, and has good applicability and designability.

Description

Technical Field

[0001] The present invention relates to the technical field of composite metal processing, and in particular to a preparation method and application of a composite metal wire or strip. Background Art

[0002] Metal composite materials are composite materials formed by combining two or more metal materials of different properties through different processes (such as hot rolling composite, diffusion composite, extrusion composite, explosive composite, etc.). Such composite materials usually combine the advantages of the two metals and can complement each other in performance, thus meeting application requirements that cannot be achieved by a single metal. For example, the composite of stainless steel and carbon steel makes the material have both high strength and corrosion resistance; the composite material can be lightweight and have good thermal conductivity when aluminum and copper are combined; the sandwich composite solder prepared by combining silver solder and copper can well relieve joint stress. At the same time, metal composites can also reduce the amount of one of the metals. For example, some precious metals (such as platinum, silver, gold, etc.) have good physical and chemical properties, but are expensive. By compounding precious metals with other common metals (such as steel, aluminum, etc.), the production cost can be greatly reduced while ensuring the material performance. Metal composite materials are not only widely used in traditional fields such as machinery, automobiles, and chemicals, but are also gradually showing great potential in high-tech fields such as aerospace and electronics. However, conventional composite processes all have their own different defects.

[0003] Hot rolling composite requires preheating of the composite billet, and then applying a certain pressure through the rolling equipment to make two or more materials deform and combine. However, this method is limited by the rolling equipment, and it is difficult to combine multi-layer or ultra-multi-layer composite strips well; at the same time, the multi-layer material is prone to deviation during the rolling process, and the multi-layer billet needs to be mechanically fixed; the high temperature preheating of the billet is prone to oxidation at the material interface, resulting in a weak rolling interface; the outer metal is prone to cracking during the rolling process, and the production process is difficult to control, resulting in a low yield.

[0004] Diffusion bonding is an improvement on hot rolling bonding, which concentrates the fixing and preheating of the rolled composite billet in a vacuum diffusion furnace to reduce interface oxidation. However, the size of the composite material is limited by the furnace body, and the production efficiency is low; at the same time, the equipment is expensive and the production investment is high.

[0005] Extrusion composite is to heat the metal to a plastic state at high temperature and extrude it to form a composite material. However, due to the difference in metal fluidity, the head and tail of the composite material extrusion will appear as a single metal or uneven composite; at the same time, hot extrusion requires special equipment and extrusion dies, which is costly.

[0006] Explosive bonding uses explosive energy to accelerate the collision of two metal materials, combining them into a composite material. It can connect different types of metals, especially metals with different chemical properties. However, due to the use of explosive energy, the operation is dangerous and has great hidden dangers in production safety. At the same time, the surface of the joint is not smooth enough in explosive bonding and needs further treatment.

[0007] In view of this, the present invention is proposed to provide a new metal cladding method to effectively improve the defects of the above conventional metal cladding methods. Summary of the invention

[0008] The first purpose of the present invention is to provide a method for preparing a composite metal wire or strip, which mainly involves rotary forging two nested metal raw materials, and then preparing a wire-shaped or strip-shaped composite metal material by wire drawing or rolling. This method can effectively solve the defects of conventional composite methods such as hot rolling composite, diffusion composite, extrusion composite, and explosive composite in terms of finished product quality, production efficiency, and cost.

[0009] The second object of the present invention is to provide a use of the composite metal material obtained by the method for preparing the composite metal wire or strip in brazing or packaging.

[0010] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0011] A method for preparing a composite metal wire or strip comprises the following steps:

[0012] Prepare a metal tube, and insert metal columns of equal height into the metal tube; wherein the metal tube comprises a first metal material, and the metal column comprises a second metal material;

[0013] Rotating a composite blank including the metal tube and the metal column;

[0014] The rotary forged blank is subjected to annealing and rolling to obtain a composite metal strip; or the rotary forged blank is subjected to wire drawing to obtain a composite metal wire;

[0015] Wherein, the cross-sectional perimeter of the composite metal strip is S, the diameter of the billet after rotary forging is D, Δh is the first pass reduction of the annealing rolling, and the units of S, D, and Δh are the same, λ=48-53.8, satisfying:

[0016]

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) The present invention proposes a method for preparing a composite metal material by rotary forging, creatively applying the rotary forging process to the preparation of a composite material, and utilizing the large deformation amount of the rotary forging process to enable the material to be composited without preheating, thereby reducing interface oxidation; at the same time, the rotary forging process continuously forges the outer metal layer, thereby refining the structure of the outer metal layer corresponding to the metal tube, thereby reducing the cracking of the outer metal layer during subsequent processing; at the same time, the present invention reduces the mechanical fixing link of the composite raw material by adopting a metal raw material with a plug-in structure similar to a hole rod; further, the present invention can achieve a significant increase in the yield of the composite strip by customizing the diameter, inner diameter and other parameters of the metal tube and metal column to adjust the ratio of the inner and outer metal layers, and the length of the composite material is not limited, thereby greatly improving the production efficiency.

[0019] (2) The composite metal wire prepared by the present invention can be used as a composite wire for bonding, and the preparation method based on the present invention can reduce the use of the precious metal coating layer, and obtain a precious metal outer layer with better coating tensile properties, and obtain a wire with a lower diameter; the composite metal strip has a structural feature similar to a sandwich, and can be used as a strip solder product after processing; it can be seen that the preparation method of the present invention has good practicality and a wide range of application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 A schematic diagram of a multi-metal composite rotary forging material of the present invention is provided;

[0022] Figure 2 Provides a microstructure diagram of the dissimilar metal interface after rotary forging in step 6 of Example 1;

[0023] Figure 3 Provides a microstructure diagram of the sandwich solder strip obtained in step 7 of Example 1 when the rolling thickness is 0.5 mm;

[0024] Figure 4 A cross-sectional view of the embodiment 1 after rotary forging in step 5 is provided;

[0025] Figure 5 A cross-sectional physical diagram of Comparative Example 1 is provided;

[0026] Figure 6 A physical picture of the finished strip of Example 1 is provided;

[0027] Figure 7 A physical picture of the finished strip of Comparative Example 1 is provided;

[0028] Figure 8 A surface micrograph of Example 1 is provided;

[0029] Fig. 9 A surface micrograph of Comparative Example 1 is provided;

[0030] Fig.10 Microscopic images of Example 4 and Comparative Example 2 obtained by drawing are provided. DETAILED DESCRIPTION

[0031] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but those skilled in the art will appreciate that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. Those who do not specify specific conditions in the embodiments are carried out according to conventional conditions or conditions recommended by the manufacturer. Those who do not specify the manufacturer for reagents or instruments used are all conventional products that can be purchased commercially. In addition, the terms "one", "1", "2", etc. are only used for descriptive purposes and cannot be interpreted as indicating or implying relative importance.

[0032] The first aspect of the present invention is to provide a method for preparing a composite metal wire or strip. Specifically, the method mainly comprises the following steps:

[0033] (1) A metal tube is prepared, and metal columns of equal height are inserted into the metal tube; wherein the metal tube comprises a first metal material, and the metal columns comprise a second metal material.

[0034] As a preferred embodiment, the inner diameter of the metal tube is slightly larger than the diameter of the metal column; in some optional embodiments, the difference between the inner diameter of the metal tube and the diameter of the metal column is between 0.02 mm and 0.3 mm.

[0035] As a more preferred embodiment, the inner diameter of the metal tube is 3 mm to 8 mm, and the thickness of the metal tube is 1 mm to 2 mm. In a further preferred embodiment, the inner diameter of the metal tube is 5 mm, and the thickness of the metal tube is 1.5 mm.

[0036] As a preferred implementation, there are two situations for the ratio of the diameter of the metal column to the diameter of the metal tube:

[0037] When preparing composite metal wires, the ratio of the diameters is not limited, and any diameter combination can be used to obtain any coated wires;

[0038] When preparing the composite metal strip, the ratio of the diameter of the metal column to the diameter of the metal tube is 0.5-0.9, including but not limited to any one of 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9 or a numerical range consisting of any two of them.

[0039] It is worth noting that, considering the thickness of the middle layer of the finished product corresponding to the metal column, the lower limit of the ratio is 0.5 to ensure that the thickness of the middle layer accounts for more than 25%, so that it is not easy to be completely reacted by the outer metal when the strip is used for brazing in the future, which plays a stress relief role; at the same time, because the strip has an outer layer-inner layer-outer layer cladding structure after rotary forging, it may be necessary to shear to remove part or one side of the outer metal, so the yield after such shearing also needs to be considered. The upper limit of the ratio is 0.9 to ensure that there is enough A metal to metallurgically combine with the workpiece and B metal to achieve brazing connection during brazing.

[0040] As a preferred embodiment, the metal tube and the metal column are coaxially arranged, which can also be understood as the pipeline of the metal tube is located in the center of the metal tube; in some other optional embodiments, the metal tube and the metal column may be non-coaxially arranged, in which case the pipeline of the metal tube is not located in the center of the metal tube, and an asymmetric multi-metal strip or a composite metal wire with a thickness emphasis on the coating layer can be obtained, but the products obtained by such embodiments have relatively few application fields and are not elaborated in the present invention.

[0041] As a preferred embodiment, before this step, the process further includes: grinding or cleaning one or both of the metal tube and the metal column to remove surface oil or oxides, etc., and then assembling the two. In some optional embodiments, the cleaning includes but is not limited to water washing, sand washing, ultrasonic washing, acid washing, organic solvent washing, etc.

[0042] As a preferred embodiment, matching interlocking structures are provided on the inner curved surface of the metal tube and the curved surface of the metal column to improve the bonding ability between the interfaces of dissimilar metals and improve the bonding strength after rotary forging; it should be noted that the inner curved surface is the inner pipeline side wall of the metal tube; in some more preferred embodiments, the interlocking structure includes but is not limited to a threaded structure, a keyway structure, a grid structure, etc.; in some more preferred embodiments, the inner curved surface of the metal tube and the curved surface of the metal column are the contact surfaces of the two, and the interlocking structure is distributed on all the contact surfaces or at both ends of the contact surfaces, that is, those skilled in the art can adaptively adjust the distribution of the interlocking structure on the contact surface according to the bonding ability of dissimilar metals.

[0043] As a preferred embodiment, the method for preparing the metal tube comprises the following steps: preparing a cylindrical ingot including the first metal material, and then drilling a circular through hole on the bottom surface of the cylindrical ingot to obtain the metal tube. It can also be understood that the pipeline structure of the metal tube is the above-mentioned circular through hole. As another preferred embodiment, when the above-mentioned process of obtaining a solid ingot and then drilling a hole is not adopted, when casting the first metal material and obtaining the cylindrical ingot, the aperture position can be reserved through a mold, and the metal tube can be cast in one go to obtain the metal tube.

[0044] As a preferred embodiment, the first metal material includes one of a silver-based material, gold, and silver; the melting point of the silver-based material is ≤720°C, and it is a low-melting-point silver-based material. The silver-based material includes but is not limited to AgCuZnNiCd, AgCuZnNiSn, AgCuZnNiCdCe, AgCuZnNiCdRE, etc.

[0045] As a more preferred embodiment, when preparing composite metal wires, the first metal material uses one of gold or silver; when preparing composite metal strips, the first metal material uses the above-mentioned silver-based material. At this time, the main application scenario of the composite metal strip is brazing filler metal for brazing.

[0046] As a further preferred embodiment, in order to take into account the cost, melting temperature and processing performance of the solder, the mass percentage ratio of the melting point reducing element to the silver element in the silver-based material is 1 to 2.3, wherein the melting point reducing element includes but is not limited to copper, zinc, tin, etc.; it can be understood that the limitation on the amount of the melting point reducing element here is on the one hand to consider that the amount of the precious metal Ag needs to be guaranteed to be the minimum, and on the other hand to consider that when the content of the melting point reducing element is too high, it is easy to produce extremely brittle phases, such as (Ag, Cu)5Zn8, etc., which affects the mechanical properties of the composite metal strip.

[0047] As a preferred embodiment, the second metal material includes one or more of copper, nickel, molybdenum, copper-nickel alloy or copper-manganese alloy, and the copper can be single crystal copper metal or foam copper.

[0048] As a preferred embodiment, the metal column also includes a third metal material; structurally, the second metal material is uniformly coated on the outside of the third metal material, and the third metal material is at the axis, and the two are coaxially arranged; it should be noted that the second metal material can be completely coated on the third metal material or partially coated.

[0049] In some more preferred embodiments, the third metal material also includes one or more of copper, nickel, molybdenum, and copper-nickel alloy, but the third metal material and the second metal material are not composed of exactly the same metal. Those skilled in the art can adaptively set the amount of the third metal material according to the metal component requirements of the target product.

[0050] like Figure 1 The figure shows the situation when the third metal material is contained. Figure 1 In the figure, A metal, B metal, and C metal represent the first, second, and third metal materials respectively. It can be seen that the three are coaxially nested and are A, B, and C from the outside to the inside. Correspondingly, in Figure 1 A schematic diagram of the longitudinal interface of the composite wire or composite strip prepared when the third metal material is present is also given.

[0051] As a preferred embodiment, the wetting angle of the first metal material on the second metal material is less than 20°, so as to ensure that the first metal material has good wetting properties on the second metal material, and then the two can achieve good metallurgical bonding after subsequent rotary forging.

[0052] As a preferred embodiment, the linear expansion coefficient of the second metal material is 4*10 -6 ℃ -1 ~15*10 -6 ℃ -1 .

[0053] As a preferred embodiment, the melting point of the first metal material is lower than that of the second metal material; thus, at the brazing temperature, metal A melts, wets the base material and metal B, and connects the base materials; metal B does not melt, but with the help of the good plasticity of metal B, it undergoes plastic deformation under the stress of the weld joint, thereby relieving stress.

[0054] (2) The composite blank including the metal tube and the metal column is subjected to rotary forging.

[0055] As a preferred embodiment, in the rotary forging, the surface reduction ratio of the first pass is 30% to 50%, including but not limited to any one of 30%, 32%, 35%, 38%, 40%, 42%, 45%, 48%, 50% or any two of them. The first pass surface reduction ratio of 30% is set to generate enough deformation heat for the inner and outer metals to achieve metallurgical composite of the two metals; the upper limit is set at 50% to prevent the outer metal from failing due to large deformation at room temperature.

[0056] As a preferred embodiment, in the rotary forging, except for the first pass, the surface reduction ratio of each rotary forging pass can be selected arbitrarily, and is not strictly limited in the present invention. The reference value is any one of 10%, 20%, 30%, 40%, 50%, 60%, 70% or a numerical range composed of any two of them.

[0057] As a preferred embodiment, the diameter range of the composite blank is 3.7mm to 30mm (which can also be understood as the diameter of the metal tube); the diameter range of the blank after rotary forging is 2mm to 16mm, that is, the following parameter D satisfies: D≤16mm.

[0058] (3) Annealing and rolling the rotary forged blank to obtain a composite metal strip; or, wire drawing the rotary forged blank to obtain a composite metal wire; wherein the cross-sectional perimeter of the composite metal strip is S, the diameter of the rotary forged blank is D, Δh is the first pass reduction of the annealing and rolling, and the units of S, D, and Δh are the same, λ=48-53.8, satisfying:

[0059]

[0060] It should be noted that the units of the above parameters are not limited in the present invention. The rationality of the formula can be satisfied when the parameters involved are measured in the same unit. Usually, S, D, and Δh are all measured in mm, and λ is an empirical coefficient and dimensionless. In actual production, the final swaging diameter of the composite material can be determined according to the target product size through the above empirical formula, reducing the need for a large number of rolling tests to determine the required diameter.

[0061] As a preferred embodiment, in the present invention, Δh / D is the diameter reduction rate of the outer metal corresponding to the metal tube under the first pass pressing, and the value range of Δh / D is 0.17 to 0.23.

[0062] As a preferred implementation, the wire drawing adopts conventional room temperature wire drawing, and the ambient temperature of the room temperature is 20°C to 30°C.

[0063] As a preferred embodiment, the annealing temperature of the annealing rolling is 450° C. to 580° C., and the annealing time of the annealing rolling is 0.5 h to 1.5 h. In the present invention, no restriction is imposed on the diameter reduction ratio of each pass of the annealing rolling.

[0064] As a preferred implementation, the wire drawing speed is 60 m / min to 300 m / min.

[0065] As a preferred implementation, the thickness of the composite metal strip is 0.1 mm to 0.5 mm, and the width of the composite metal strip is 3 mm to 22 mm.

[0066] As a preferred implementation, the diameter of the composite metal wire is 20 μm to 100 μm.

[0067] As a preferred embodiment, after this step, the composite metal strip or the composite metal wire is further included: cleaning the composite metal strip or the composite metal wire to remove impurities introduced in this process or oxides generated, etc. In some optional embodiments, the cleaning includes but is not limited to water washing, sand washing, ultrasound, acid washing, organic solvent washing, etc.

[0068] As an optional embodiment, when preparing a composite metal strip, after this step, it also includes: slitting to remove both sides of the composite metal strip, generally cutting off the portion not containing the second metal material, for application in specific scenarios such as brazing.

[0069] The second aspect of the present invention is to provide a use of a composite metal material obtained by the preparation method of a composite metal wire or strip as described in the first aspect in brazing or packaging; including but not limited to the use of the composite metal wire or strip prepared by the first aspect as a composite bonding wire in packaging, or as a composite solder in brazing, specifically, including but not limited to bonding wire or solder products prepared by the preparation method of the first aspect, or the use of products prepared based on the preparation method of the first aspect in specific fields, etc.; it is worth noting that when including the composite metal wire or strip prepared as in the first aspect, any product or method can be regarded as an embodiment of this aspect.

[0070] Example 1

[0071] Step 1: First, prepare a rod-shaped low-melting-point silver-based solder with a composition of BAg50CuZnNiCd and a cross-sectional diameter of 7.3 mm;

[0072] Step 2: Use a lathe to drill a circular through hole with a diameter of 3.9 mm in the center of the BAg50CuZnNiCd solder;

[0073] Step 3: Prepare a copper rod with a cross-sectional diameter of 3.88 mm;

[0074] Step 4: Use sandpaper, alcohol, etc. to polish and clean the surface of the copper rod;

[0075] Step 5: inserting the copper rod into the through hole of the silver-based solder to obtain a composite blank;

[0076] Step 6: Place the composite blank into a rotary forging device for diameter reduction, the first pass reduction rate is 32.4%, and the diameter of the composite material after the first pass rotary forging is 6 mm; then continue rotary forging to obtain a composite wire with a final diameter of 5 mm;

[0077] Step 7: further annealing the composite wire at 550° C. for 1 h, and rolling to obtain a strip with a thickness of 0.3 mm and a width of 10 mm;

[0078] Step 8: Clean the surface of the composite solder material to remove impurities introduced during rolling or drawing;

[0079] Step 9: Observe the width of the pure metal (copper layer) on both sides of the strip through a stereo microscope, and cut off the copper part to obtain a sandwich solder strip with a width of 7.8 mm. The solder of this embodiment can be used for brazing of cemented carbide and polycrystalline diamond materials.

[0080] like Figure 2 The figure shows the microstructure of the dissimilar metal interface after rotary forging in step six of this embodiment; Figure 3 The thickness cross-section microstructure diagram of the sandwich solder strip obtained in step 7 of this embodiment when the rolling thickness is 0.5 mm is provided. Figure 3 From top to bottom, there is silver solder layer-copper layer-silver solder layer, and the corresponding thicknesses are 169.13μm, 187.13μm, and 142.76μm, respectively.

[0081] from Figure 2 , 3 It can be seen that after forging, the silver solder and copper have achieved a good combination without obvious gaps. From the material microstructure, it can be seen that the outer layer of silver-based solder after rotary forging is fine and uniform, and there is no obvious agglomeration of the compound (the compound size is mostly less than 10μm), which is conducive to the subsequent wire drawing process; in the subsequent rolling process of the composite strip, it is found that the thickness of the composite material is uniform, the position of the middle layer metal is stable, and there is no deviation of the inner layer metal.

[0082] Example 2

[0083] It is basically the same as Example 1, except that the copper rod in step three is replaced by a nickel rod.

[0084] Example 3

[0085] Step 1: First, prepare a rod-shaped low-melting-point silver-based solder with a composition of BAg50CuZnNiCd and a cross-sectional diameter of 23 mm;

[0086] Step 2: Use a lathe to drill a circular through hole with a diameter of 16.2 mm in the center of the BAg50CuZnNiCd solder;

[0087] Step 3: Prepare a pure copper rod with a cross-sectional diameter of 16 mm;

[0088] Step 4: Use sandpaper, alcohol, etc. to polish and clean the surface of the copper rod;

[0089] Step 5: inserting the copper rod into the through hole of the silver-based solder to obtain a composite blank;

[0090] Step 6: Place the composite blank into a rotary forging device for diameter reduction, the first pass reduction rate is 36%, and the diameter of the composite material after the first pass rotary forging is 18.4 mm; then continue rotary forging to obtain a composite wire with a final diameter of 16 mm;

[0091] Step 7: further annealing and rolling the composite wire to obtain a wide strip with a thickness of 0.5 mm and a width of 21 mm;

[0092] Step 8: Clean the surface of the composite solder material to remove impurities introduced during rolling or drawing;

[0093] Step 9: Observe the width of the pure metal (copper layer) on both sides of the strip through a stereo microscope, and cut off the pure copper part to obtain a sandwich solder strip with a width of 11.2 mm.

[0094] For the above-mentioned embodiments 1 to 3, the cross-sectional perimeter of the composite metal strip is S, the diameter of the billet after rotary forging in step 6 is D, and Δh is the first pass reduction of annealing rolling in step 7, and the statistical values ​​are as follows in Table 1. Based on Table 1, it can be seen that the following meets

[0095]

[0096] The empirical formula of .

[0097] Table 1

[0098]

[0099] As can be seen from Table 1, the S calculated by the empirical formula provided by the present invention is 经验值 , compared with the S obtained from the actual physical products obtained in Examples 1 and 3 实际值 The difference between the two is very small, which basically meets the universal conclusion provided by the empirical formula.

[0100] Example 4

[0101] Step 1: First, prepare a pure silver bar with a diameter of 8 mm;

[0102] Step 2: Use a lathe to drill a circular through hole with a diameter of 3.9 mm in the center of the pure silver bar;

[0103] Step 3: Prepare a metal copper rod with a diameter of 3.88 mm;

[0104] Step 4: Use sandpaper, alcohol, etc. to polish and clean the surface of the copper rod;

[0105] Step 5: Insert the copper rod into the sterling silver rod;

[0106] Step 6: Place the composite blank into a rotary forging device for diameter reduction. After the first rotary forging, the diameter of the composite material is 6.5 mm, and the area reduction rate is 34%. Then continue rotary forging to obtain a composite wire with a final diameter of 5 mm.

[0107] Step 7: Clean the surface of the composite wire, and perform multiple annealing and wire drawing to obtain an Ag-Cu composite bonding wire with a wire diameter of 20 μm.

[0108] Test Example 1

[0109] A commercially available copper-silver based solder prepared by hot rolling composite was used as comparative example 1, and its performance was compared with that of examples 1 to 3.

[0110] S1. Yield rate: Examples 1 to 3 were repeated 200 times, and the average yield rate of Examples 1 to 3 was 65%. The theoretical yield rate of the swaged composite material is related to the diameter of the inner metal layer. The larger the diameter of the inner metal layer, the more sandwich structure products are obtained by rolling, and the higher the yield rate; however, the yield rate of sandwich solder obtained by traditional hot rolling composite is usually less than 50%, which shows that the preparation process of the present invention has obvious advantages in yield rate.

[0111] S2. Interface bonding performance: The intermediate product after the rotary forging in step 5 of Example 1 was longitudinally cut to obtain a macroscopic physical image of the cross section, as shown in FIG. Figure 4 As shown in FIG. 1 , the composite interface obtained by rotary forging is tightly bonded, free of impurities, and free of oxidation slag. Figure 5 As shown, severe oxidation can be observed in the cross section.

[0112] At the same time, when the sandwich brazing material is prepared by the rotary forging process, the outer metal covers the inner metal, and the inner and outer metals deform synchronously. However, during the rolling compounding process, due to the different deformation resistance of the inner and outer metals, the internal metal deviates, which is unavoidable during hot rolling compounding. Figure 6, Figure 7 The actual pictures of the finished strips of Example 1 and Comparative Example 1 are provided respectively.

[0113] S3. Internal deviation: The outer metal of the sandwich solder prepared by rotary forging process has fine and uniform structure after rotary forging. Figure 8 As shown in the microscopic image of the surface of the object in Example 1, the maximum grain size is 20.36μm. At this time, the outer metal processing performance is good, and no edge cracking occurs during the rolling process. However, in Comparative Example 1, there are large-sized grains in the outer metal structure, and the grain size reaches 42.13μm. If the large-sized grains are distributed at the edge of the strip, edge cracking is likely to occur during the rolling process. Fig. 9 shown.

[0114] S4. Welding test: The products of each embodiment and comparative example 1 were used as solders, and welding experiments of cemented carbide (YG8) and steel (42CrMo) were carried out using high-frequency induction heating equipment. Three independent experiments were carried out for each example, and the shear strength of the joint was tested. The results are shown in Table 2.

[0115] Table 2

[0116]

[0117]

[0118] Test Example 2

[0119] A commercially available silver-copper bonding wire prepared by a drawing method was used as comparative example 2, and its performance was compared with that of example 4.

[0120] When comparative example 2 was drawn to a diameter of 3 mm and 1.3 mm, and when step 7 of example 4 was drawn to a diameter of 3 mm and 1.3 mm, microscopic inspection was performed on the outer layer of metallic silver, respectively, to obtain Fig.10 The four SEM images shown in the figure respectively correspond to the microstructure of the external metal silver of Comparative Example 2 when the diameter is 3 mm and 1.3 mm on the left, and the microstructure of the external metal silver of Example 4 when the diameter is 3 mm and 1.3 mm on the right; Fig.10 It can be found that the grain size of the organization after rotary forging is much smaller than that after traditional drawing, and the organization is more uniform; after drawing to a diameter of 1.3 mm in Example 4, the grain size contrast is more obvious, the grain size of the rotary forging organization is significantly smaller than 50 μm, and the grain size of the wire drawing organization is greater than 50 μm.

[0121] Although the present invention has been illustrated and described with specific embodiments, it should be appreciated that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some or all of the technical features thereof may be replaced by equivalents without departing from the spirit and scope of the present invention. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention. Therefore, this means that all such replacements and modifications within the scope of the present invention are included in the appended claims.

Claims

1. A method for preparing a composite metal wire or strip, characterized in that: The steps include: Prepare a metal tube, and insert metal columns of equal height into the metal tube; wherein the metal tube comprises a first metal material, and the metal column comprises a second metal material; Rotating a composite blank including the metal tube and the metal column; The rotary forged blank is subjected to annealing and rolling to obtain a composite metal strip; or the rotary forged blank is subjected to wire drawing to obtain a composite metal wire; Wherein, the cross-sectional perimeter of the composite metal strip is S, the diameter of the billet after rotary forging is D, Δh is the first pass reduction of the annealing rolling, and the units of S, D, and Δh are the same, λ=48-53.8, satisfying:

2. The method for preparing a composite metal wire or strip according to claim 1, characterized in that: The value range of Δh / D is 0.17 to 0.23; And / or, when S, D, and Δh are all measured in mm, D≤16mm.

3. The method for preparing a composite metal wire or strip according to claim 1, characterized in that: The difference between the inner diameter of the metal tube and the diameter of the metal column is 0.02 mm to 0.3 mm; And / or, when preparing the composite metal strip, the ratio of the diameter of the metal column to the outer diameter of the metal tube is 0.5 to 0.

9.

4. The method for preparing a composite metal wire or strip according to claim 1, characterized in that: A matching engaging structure is provided on the inner curved surface of the metal tube and the curved surface of the metal column; The engaging structure includes at least one of a thread structure, a keyway structure or a grid structure.

5. The method for preparing a composite metal wire or strip according to claim 1, characterized in that: The first metal material includes one of a silver-based material, gold, and silver; wherein the melting point of the silver-based material is ≤720°C; Preferably, the mass percentage ratio of the melting point reducing element to the silver element in the silver-based material is 1 to 2.3, and the melting point reducing element includes copper, zinc or tin.

6. The method for preparing a composite metal wire or strip according to claim 1, characterized in that: The metal column further comprises a third metal material, and the second metal material is different from the third metal material; The second metal material is uniformly coated on the third metal material, and the third metal material is located at the axis of the metal column; Preferably, the second metal material and / or the third metal material includes one or more of copper, nickel, molybdenum, copper-nickel alloy or copper-manganese alloy.

7. The method for preparing a composite metal wire or strip according to claim 1, characterized in that: The wetting angle of the first metal material on the second metal material is less than 20°; and / or, the melting point of the first metal material is lower than that of the second metal material; And / or, the linear expansion coefficient of the second metal material is 4*10 -6 ℃ -1 ~15*10 -6 ℃ -1 .

8. The method for preparing a composite metal wire or strip according to claim 1, characterized in that: In the rotary forging, the surface reduction ratio of the first rotary forging is greater than 20%; Preferably, in the rotary forging, the surface reduction ratio of the first rotary forging is 30% to 50%.

9. The method for preparing a composite metal wire or strip according to claim 1, characterized in that: Before the rotary forging is performed, the method further includes: grinding or cleaning the metal tube and the metal column; After the rotary forging, the method further includes: cleaning the composite metal wire or composite metal strip; Preferably, the cleaning includes one or more of water washing, sand washing, ultrasound, acid washing or organic solvent washing.

10. Use of the composite metal material obtained by the method for preparing a composite metal wire or strip according to any one of claims 1 to 9 in brazing or packaging.

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