Brass-aluminum brass composite material and preparation method and application of warm compounding thereof

Abstract

This application provides a brass-aluminum-brass composite material and its preparation method and application. The preparation method includes: heating a first brass, an aluminum material, and a second brass material to a temperature of 400-500℃ for 2-6 minutes, with a thickness ratio of 1:(1-8):1 for the first brass, aluminum material, and second brass; rolling the heated material according to a brass-aluminum-brass structure, with a single-pass rolling reduction rate of 50%-70%; and then cold rolling to obtain a composite material of the target thickness. The solid-solid-temperature composite process softens the brass and aluminum alloy, making the metal flow and synergistic deformation more favorable during rolling. Simultaneously, the material is in a hot state during rolling, increasing the self-diffusion ability of copper and aluminum at the interface, enabling mutual diffusion of copper and aluminum atoms. The bonding interface transitions from mechanical bonding to metallurgical bonding, forming an IMC layer, which improves the bonding strength of the composite material.

Description

Technical Field

[0001] This application relates to the field of metal composite material processing, and in particular to a brass-aluminum-brass composite material and its preparation method and application in a warm composite process. Background Technology

[0002] Copper-aluminum composites are widely used in LED lighting due to their combination of copper's high electrical and thermal conductivity and aluminum's lightweight properties. Traditional pure copper or brass materials are expensive and heavy, while pure aluminum has insufficient electrical conductivity; therefore, copper-aluminum composites have become an ideal alternative.

[0003] Currently, the main methods for preparing copper-aluminum composite materials include solid-solid composite (rolling, explosion, welding), solid-liquid composite (casting and rolling), and liquid-liquid composite. Among these, rolling composite has become the mainstream method in industrial production due to its simple equipment, short process, and low cost. However, for copper-aluminum-copper composite materials, the presence of zinc in brass hinders the interfacial bonding between brass and aluminum, thus affecting the bonding strength of the copper-aluminum-copper composite material.

[0004] Therefore, improving the bonding strength between brass and aluminum is an urgent problem to be solved. Summary of the Invention

[0005] This application provides a brass-aluminum-brass composite material and its preparation method and application in warm bonding, to meet the requirements of lightweight, heat dissipation, electrical conductivity and mechanical properties of LED brackets.

[0006] In a first aspect, this application provides a method for preparing a brass-aluminum-brass composite material through a warm composite process, the method comprising the following steps:

[0007] The first brass, aluminum and second brass are heat-treated at a temperature of 400-500℃ for 2-6 minutes. The thickness ratio of the first brass, the aluminum and the second brass is 1:(1-8):1.

[0008] The material, after heat preservation, is subjected to rolling composite treatment at 400~500℃ according to the brass-aluminum-brass structure. The rolling composite treatment is a single-pass rolling process with a single-pass rolling reduction rate of 50%~70%.

[0009] The material undergoing the rolling composite treatment is then subjected to cold rolling to obtain a brass-aluminum-brass composite material of the target thickness.

[0010] Furthermore, the aluminum material is selected from one of the following: 1-series aluminum alloys, 3-series aluminum alloys, 5-series aluminum alloys, and 8-series aluminum alloys;

[0011] And / or, the brass is selected from one of H58, H59, H60, H62, H62.5, H63, H65, H66, H68, H70, H80, H85, H90, H95, and H96.

[0012] Furthermore, before cold rolling the rolled composite material, the preparation method further includes:

[0013] The temperature of the material undergoing the rolling composite treatment is reduced to room temperature.

[0014] Furthermore, prior to the heat treatment, the surfaces of the first brass and the second brass each comprise a pure copper layer of 200-1000 nm.

[0015] Furthermore, the heat treatment of the first brass, aluminum, and second brass includes:

[0016] The first brass, the aluminum material, and the second brass are stacked in a brass-aluminum-brass structure and then subjected to the heat treatment.

[0017] Furthermore, the cold rolling process includes roughing and finishing rolling;

[0018] The total reduction rate of the roughing process is 60%~70%, the single-pass reduction rate is 15%~30%, and the rolling speed is 1-10m / min;

[0019] The total reduction rate of the finishing rolling process is 60%~70%, the single-pass reduction rate is 15%~30%, and the rolling speed is controlled at 1-10m / min.

[0020] Furthermore, the preparation method further includes:

[0021] After rough rolling, intermediate annealing is performed at a temperature of 350~450℃ for a time of 4~12 minutes.

[0022] After the finishing rolling, the finished product is annealed at a temperature of 350~450℃ for a time of 4~12 minutes.

[0023] In a second aspect, this application provides a brass-aluminum-brass composite material, wherein the brass-aluminum-brass composite material is prepared by any of the preparation methods described in the first aspect, and the thickness ratio of the brass layer, the aluminum layer and the brass layer in the brass-aluminum-brass composite material is 1:(1~8):1.

[0024] Furthermore, an intermetallic compound layer of 200-500 nm is included between the brass layer and the aluminum layer.

[0025] Secondly, this application provides an LED bracket, which is prepared by the brass-aluminum-brass composite material described in the second aspect.

[0026] This application provides a brass-aluminum-brass composite material, its preparation method, and its application. The preparation method employs a solid-solid-temperature composite process, heating brass and aluminum alloys. This softens the brass and aluminum alloys, facilitating metal flow and coordinated deformation during rolling, thus filling interface defects. Simultaneously, the materials are in a hot state during rolling, increasing the self-diffusion capacity of copper and aluminum at the interface, enabling inter-diffusion of copper and aluminum atoms. The bonding interface transitions from mechanical bonding to metallurgical bonding, forming an IMC layer. Compared to conventional cold rolling composite processes, the IMC layer formed by solid-solid-temperature composite rolling can improve the bonding strength of the composite material. Attached Figure Description

[0027] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0028] Figure 1 A flowchart illustrating a method for preparing a brass-aluminum-brass composite material through warm bonding, as provided in this application;

[0029] Figure 2 This is a cross-sectional SEM image of the brass-aluminum-brass composite material from Example 1.

[0030] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0032] The difference between the solidus temperature and the liquidus temperature of 5083 aluminum alloy is about 58℃, which means that the crystallization temperature range of the material is about 58℃. The large crystallization temperature range is not conducive to the solid-liquid composite casting and rolling process, and a solid-solid rolling composite process is required.

[0033] However, when using a solid-solid room-temperature rolling composite process, the zinc in brass has a certain hindering effect on the formation of copper-aluminum compounds, resulting in a weaker bond compared to pure copper and aluminum alloys. Therefore, conventional solid-solid cold composite processes cannot effectively guarantee interlayer bonding.

[0034] In view of this, to improve the deformation plasticity of the material during the rolling process, a solid-solid-temperature composite process is adopted. This process heats the brass and aluminum alloy, improving their properties and facilitating metal flow and coordinated deformation during rolling. Simultaneously, the material is in a hot state during rolling, allowing for copper-aluminum self-diffusion at the interface, enabling inter-diffusion of copper and aluminum atoms. This transitions the bonding interface from mechanical to metallurgical bonding, increasing bonding strength and preventing material delamination.

[0035] Figure 1 A flowchart of a method for preparing a brass-aluminum-brass composite material by warm bonding is provided in this application, as shown below. Figure 1 As shown, the preparation method includes the following steps:

[0036] S1. Heat the first brass, aluminum and second brass at a temperature of 400~500℃ and hold for 2-6 minutes. The thickness ratio of the first brass, aluminum and second brass is 1:(1~8):1.

[0037] S2. After heat preservation, the material at 400~500℃ is subjected to rolling composite treatment according to the brass-aluminum-brass structure. The rolling composite treatment is a single-pass rolling process with a single-pass rolling reduction rate of 50%~70%.

[0038] S3. The material that has undergone rolling composite treatment is subjected to cold rolling to obtain a brass-aluminum-brass composite material of the target thickness.

[0039] The heat treatment temperature can be 400℃, 425℃, 450℃, 475℃, 500℃, or any combination thereof. The recrystallization temperature of brass is above 350℃, specifically related to the zinc content. A temperature range of 400~500℃ allows for partial recrystallization of brass, reducing its hardness and deformation resistance, making subsequent rolling easier and reducing surface cracks. Temperatures below 500℃ avoid inducing grain growth or the impact of Zn volatilization on material properties. Aluminum has a lower softening temperature, ideally between 400~500℃, to maintain its high ductility. Within this temperature range, the deformation resistance of both brass and aluminum is significantly reduced, plasticity is increased, the deformation difference between the two metals is reduced, and the synergistic deformation capability of brass and aluminum is improved.

[0040] The holding time can be 2 min, 3 min, 4 min, 5 min, 6 min, or any combination of the above. Holding time of 2 to 6 minutes is sufficient to trigger softening / recovery, avoid excessively large grains or Zn volatilization, and maintain uniform microstructure.

[0041] To improve the mechanical, electrical, and thermal conductivity of brass-aluminum-brass composites, the thickness ratio of brass, aluminum, and brass is controlled within 1:(1~8):1. For example, ratios of 1:1:1, 1:3:1, 1:5:1, 1:6:1, 1:8:1, or any combination of two of these ratios. Controlling the thickness ratio within this range allows the composite material to achieve tensile strength, hardness, and thermal conductivity close to those of brass, while also possessing excellent thermal and electrical conductivity.

[0042] In step S2, since brass and aluminum are dissimilar metals, both have oxide layers on their surfaces, resulting in low interlayer bonding strength. The rolling composite process, with a single-pass reduction of 50% to 70%, can crush the oxide films on the interlayer surfaces of the two metals, exposing fresh metal at the interlayer interface and allowing them to come into close contact, thereby achieving good interfacial bonding and improving the interlayer bonding strength.

[0043] Brass-aluminum alloy-brass is heated and subjected to large deformation rolling. The material deforms above the recrystallization temperature, resulting in high softening and good high-temperature plasticity. Since the rolling process is heated, diffusion annealing can be avoided after rolling. The residual heat of the material can be used to allow the intermetallic compound at the copper-aluminum interface to diffuse, forming a discontinuous intermetallic compound (IMC) layer.

[0044] Solid-solid temperature composite involves rolling and deforming materials after they have been subjected to high temperatures. The resistance to deformation is much smaller, so the required rolling force is less than that for solid-solid cold composite. The requirements for rolling composite equipment are also lower.

[0045] During the rolling deformation process, the three-layer composite material undergoes dynamic recrystallization, resulting in grain refinement. Simultaneously, due to the hereditary nature of the microstructure, the initial fine grains are further broken down by cold rolling in step 3. After annealing, a uniform fine grain structure is obtained, which improves the mechanical properties of the material.

[0046] In step S3, cold rolling is performed to reduce the thickness of the composite material and obtain the desired target thickness. The cold rolling process can be carried out by a single set of rolling passes followed by annealing to obtain the composite material of the target thickness, or by two rolling passes: rough rolling first, intermediate annealing, and then finish rolling, followed by product annealing to obtain the composite material of the target thickness.

[0047] The above-described preparation method employs solid-solid-temperature composite technology, heating brass and aluminum alloys softens them, facilitating metal flow and coordinated deformation during rolling and filling interfacial defects. Simultaneously, the materials are in a hot state during rolling, increasing the self-diffusion capacity of copper and aluminum at the interface, enabling inter-diffusion of copper and aluminum atoms. This transitions the interface bonding from mechanical to metallurgical, forming an IMC layer. Compared to conventional cold-rolling composite processes, which rely primarily on mechanical interlocking for interfacial bonding, the presence of Zn in brass makes the interface more prone to forming uneven microstructures (such as Zn-rich regions), reducing the effectiveness of interfacial interlocking. Therefore, solid-solid-temperature composite technology, by forming an IMC layer, can improve the bonding strength of the composite material.

[0048] In some embodiments, the aluminum material is selected from one of the 1-series, 3-series, 5-series, and 8-series aluminum alloys. The 5-series aluminum alloy 5083 is representative, as its thermal and electrical conductivity are higher than that of brass C2680 (H65 / H66). Therefore, the composite material exhibits superior thermal and electrical conductivity compared to single-metal brass. Furthermore, aluminum alloys have a lower density than brass, thus the composite material offers a weight reduction effect compared to single-metal materials.

[0049] In some embodiments, the copper mass fraction in the brass is greater than 58%. The first and second brasses on both sides of the aluminum can be selected from one of the brasses H58, H59, H60, H62, H62.5, H63, H65, H66, H68, H70, H80, H85, H90, H95, and H96 in GB / T 5231-2022.

[0050] In some embodiments, before cold rolling the rolled composite material, the temperature of the rolled composite material is reduced to room temperature, and cold rolling is performed at room temperature.

[0051] In some embodiments, prior to heat treatment, a layer of pure copper is deposited on the brass surface (i.e., the surfaces of the first brass and the second brass), the brass surface comprising a pure copper layer of 200-1000 nm. For example, 200 nm, 400 nm, 600 nm, 800 nm, 1000 nm, or any combination thereof.

[0052] The pure copper layer acts as a transition barrier, effectively preventing direct reaction between zinc and aluminum in brass, thus avoiding the formation of complex IMC layers. The interface between pure copper and aluminum facilitates the formation of a more stable IMC layer. The pure copper layer provides stronger interfacial bonding between brass and aluminum alloys, thereby enhancing the overall mechanical properties of the composite material.

[0053] There are no restrictions on the methods used to apply a layer of pure copper to the surface of brass; electroplating, spraying, or hot-dip galvanizing are all acceptable.

[0054] The pure copper on the brass surface can be set only on the surface that contacts the aluminum, while the other side can be left unset to reduce costs.

[0055] In some embodiments, the heat treatment in step S1 can be performed on the three types of sheet or roll materials separately. Performing heat treatment separately allows for precise control of the heating temperature of each material.

[0056] In some embodiments, the heat treatment in step S1 can be performed by stacking three types of sheets or coils in a brass-aluminum-brass structure. Uniform heat treatment after stacking promotes initial interfacial diffusion and metallurgical bonding of the composite material during heating, enhancing the bonding strength before rolling. Stacking and heating also helps the materials soften synchronously in a hot state, reducing rolling unevenness caused by differences in material hardness, and ensuring consistent thickness and surface flatness of the composite sheet.

[0057] In some embodiments, the rolling speed for the rolling composite process is 1-5 m / min. For example, 1 m / min, 3 m / min, 5 m / min, or any combination thereof. A rolling speed of 1-5 m / min helps prevent the metal from heating up too quickly during rolling, thereby ensuring the uniformity and adhesion of the composite layer.

[0058] In some embodiments, after the rolling composite treatment, the material is first trimmed and brushed. The burrs on the surface are trimmed, with a single-sided removal of 5-15 mm. After trimming, the material is brushed, which involves alkaline washing and water washing at a brushing speed of 1-4 m / min to ensure that the material surface is clean and free of defects such as burrs and serrations on the edges.

[0059] In some embodiments, the cold rolling process includes roughing and finishing rolling.

[0060] The total reduction rate of roughing is 60%~70%, the single-pass reduction rate is 15%~30%, the pre-rolling tension and post-rolling tension are 300~600Kg, the rolling speed is 1-10m / min, and the surface roughness Ra of the work rolls is 0.4~1.2µm.

[0061] By applying a high reduction rate, the material's grains are stretched and reorganized, resulting in smaller grains and thus increased metal strength. Therefore, a higher reduction rate (60%–70%) helps refine the grains and improve the material's strength and hardness. In step 3, the material surface no longer has an oxide layer, so an excessively high single-pass reduction rate is unnecessary. An excessively high single-pass reduction rate can lead to significant material deformation, easily causing cracks or surface defects. Therefore, a single-pass reduction rate of 15%–30% helps achieve sufficient plastic deformation without damaging the material.

[0062] The purpose of tension is to maintain the tension balance of the material during the rolling process. The range of front tension and back tension is 300~600kg, which helps to tighten the metal strip during rolling, reduce warping or bending caused by plastic deformation of the metal, reduce uneven stretching or uneven thickness, and ensure uniform thickness of the entire sheet or strip.

[0063] Roll surface roughness (Ra) refers to the microscopic unevenness of the roll surface, which has a significant impact on the surface quality of metal strip. Maintaining a roll surface roughness of 0.4~1.2µm can make the surface of the rolled material smoother, especially in subsequent finishing rolling processes with high precision requirements.

[0064] The total reduction rate of the finishing rolling process is 60%~70%, the single-pass reduction rate is 15%~30%, the pre-rolling tension and post-rolling tension are 200~400Kg, the rolling speed is controlled at 1-10m / min, and the surface roughness Ra of the work rolls is 0.2~0.8µm.

[0065] The purpose of finish rolling is to further reduce the thickness of the material, improve surface quality and precision, and enhance the mechanical properties of the final product. Since the material surface has already undergone preliminary rough rolling, meticulous finish rolling can further eliminate residual deformation and surface defects. In this scheme, the rolling parameters for finish rolling can be the same as for rough rolling, but the surface roughness of the work rolls in finish rolling is lower, with Ra ranging from 0.2 to 0.8 µm. For example, 0.2 µm, 0.4 µm, 0.6 µm, 0.8 µm, or any combination of two of these values. Lower surface roughness reduces friction between the rolls and the metal strip, resulting in a smoother, scratch-free metal surface.

[0066] In some embodiments, the preparation method further includes:

[0067] After rough rolling, intermediate annealing is performed at a temperature of 350~450℃ for 4~12 minutes.

[0068] The purpose of intermediate annealing after rough rolling is to eliminate the work hardening and internal stress accumulated during rough rolling, so as to facilitate subsequent finish rolling.

[0069] After finishing rolling, the finished product is annealed at a temperature of 350~450℃ for 4~12 minutes.

[0070] After precision rolling, the product has achieved the target dimensions and surface accuracy, but the metal will still have residual stress and a certain degree of work hardening. Therefore, finished product annealing is required to stabilize the microstructure and properties.

[0071] In some embodiments, prior to heat treatment, the preparation method further includes:

[0072] The surfaces of the first and second brass materials, as well as the aluminum material, are roughened using an online roughening machine.

[0073] An online dry metal texturing machine is used to texturize each single layer of metal, mechanically removing the surface oxide layer and increasing surface roughness. The texturing process is performed at a grinding speed of 1-3 m / min to ensure uniform grinding.

[0074] To ensure that the shape and dimensions of the finished product meet the requirements, the cold-rolled material needs to be straightened at a linear speed of 5-10 m / min. After straightening, the plate is flat.

[0075] In some embodiments, the rolling composite process in step 2 and the cold rolling process in step 3 can be performed with electromagnetic pulse assistance.

[0076] During rolling, a 10-15T pulsed magnetic field (frequency 50Hz) is applied, with the magnetic field direction parallel to the rolling direction. The electromagnetic pulse promotes dislocation movement (increasing dislocation density), and the electromagnetic eddy currents generate localized Joule heating, which accelerates atomic diffusion and promotes the formation of the IMC layer. Furthermore, the pulsed magnetic field reduces the rolling force, resulting in finer grain sizes in the dynamic recrystallization process.

[0077] The final target thickness range is 0.05~1.5mm, and the dimensional tolerance can be controlled to ±0.003mm; the width range is 0.8~1000mm, and the dimensional tolerance can be controlled to ±0.1mm.

[0078] This application also provides a brass-aluminum-brass composite material, which is prepared by any of the above preparation methods, wherein the thickness ratio of the brass layer, the aluminum layer and the brass layer in the brass-aluminum-brass composite material is 1:(1~8):1.

[0079] Composite materials within this thickness range exhibit superior electrical and thermal conductivity and lower density while ensuring that the mechanical properties of the composite material are close to those of brass.

[0080] In some embodiments, the prepared brass-aluminum-brass composite material includes a 200-500 nm intermetallic compound layer between the brass layer and the aluminum layer. The intermetallic compound layer is less than 500 nm to prevent brittleness at the interface between the two layers; the intermetallic compound layer is greater than 200 nm to ensure interlayer bonding and prevent interface delamination or separation. Therefore, the 200-500 nm intermetallic compound layer provides sufficient bonding strength without being too thick and increasing brittleness.

[0081] This application also provides an LED bracket, which is prepared by the above-mentioned brass-aluminum-brass composite material.

[0082] Compared to pure copper brackets, LED brackets are cheaper in terms of material cost, and their mechanical properties are close to those of brass, while exhibiting better electrical and thermal conductivity and lower density.

[0083] The present invention will be further described below through specific embodiments.

[0084] Example 1

[0085] The material uses C2680 brass and 5083 aluminum alloy, with the thickness ratio of the brass layer (the layer corresponding to the first brass), the aluminum alloy layer (the layer corresponding to the aluminum material), and the brass layer (the layer corresponding to the first brass) being 1:1:1.

[0086] Choose brass C2680 raw material with specifications of 0.8mm×220mm×Coil, and aluminum alloy 5083 raw material with specifications of 0.8mm×220mm×Coil.

[0087] The production implementation steps are as follows:

[0088] First, the C2680 brass and 5083 aluminum alloy raw materials are surface-washed to remove surface oil and improve cleanliness. Then, the brass-aluminum alloy-brass composite surface is mechanically roughened online using a top-middle-bottom "sandwich" structure, removing the oxide layer from the interface layer surface through a rotating mechanical brush.

[0089] The roughened three-layer metal structure enters an induction heating furnace, where the material is rapidly heated to 420±10℃. It then continuously enters an online heating furnace for heat preservation at 420±5℃ for 6 minutes. Immediately after heat preservation, it is subjected to continuous composite rolling on a four-roll composite mill with a single-pass reduction rate of 70% and a composite rolling speed of 2 m / min.

[0090] Materials subjected to warm composite rolling do not require diffusion annealing. After diffusion annealing, the material is trimmed and cleaned, with 10±0.1mm removed from each side to remove burrs and prevent breakage during subsequent rolling. Surface cleaning is also performed to ensure surface cleanliness.

[0091] Rough rolling was performed on a 20-roll mill with a total rolling reduction of 70%, divided into 4 passes, with a single pass reduction of 17.5%, and a rolling speed of 1 m / min. Intermediate annealing was carried out in a continuous annealing furnace at a temperature of 440±5℃ for 5 min to eliminate work hardening of the material.

[0092] The material is finished rolled on a 20-roll mill with a total reduction of 70% in three passes, each with a reduction of 23.3% at a rolling speed of 1 m / min. After finish rolling, the finished product undergoes annealing under the same conditions as intermediate annealing. Following annealing, it is tension leveled at a speed of 3 m / min, then trimmed, cleaned, and packaged. The final finished composite material has dimensions of 0.17 mm × 140 mm × Coil, with a three-layer thickness ratio of 1:1:1.

[0093] Example 2

[0094] In Example 2, the materials used are the same as in Example 1, with a brass-aluminum alloy-brass material thickness ratio of 1:8:1. The copper alloy C2680 material has a specification of 0.3mm × 220mm × Coil; the aluminum alloy raw material has a specification of 2.4mm × 220mm × Coil; and the final rolled thickness is 0.14mm × 140mm × Coil. The washing and texturing of the raw materials are the same as in Example 1, and the rolling is carried out using the same online heating temperature composite method as in Example 1. The single-pass composite reduction rate is 70%, and the composite rolling speed is 2m / min.

[0095] Rough rolling was performed on 20 rolls with a total rolling reduction of 60%, divided into 4 passes, with a single pass reduction of 15%, and a rolling speed of 1 m / min. Intermediate annealing was carried out in a continuous annealing furnace at a temperature of 350±5℃ for 5 min to eliminate work hardening of the material.

[0096] The product is finished on a 20-roll mill with a total rolling reduction of 65% divided into 3 passes, with a single pass reduction of 22%. The rolling speed is 1 m / min. The annealing conditions for the finished product are the same as those for intermediate annealing. After annealing, it undergoes tension leveling at a speed of 3 m / min, followed by edge trimming, and finally cleaning and packaging. The final composite material has a thickness ratio of 1:8:1 for its three layers.

[0097] Example 3

[0098] The preparation method of this embodiment is basically the same as that of Example 1, except that the thickness ratio of brass-aluminum alloy-brass material is 1:4:1.

[0099] Example 4

[0100] The preparation method of this embodiment is basically the same as that of Example 1. The difference is that the roughened three-layer metal structure enters the induction heating furnace, the material is rapidly heated to 500°C, and then continuously enters the online heating furnace for heat preservation. The heat preservation temperature is 500°C and the heat preservation time is 6 minutes.

[0101] Example 5

[0102] The preparation method of this embodiment is basically the same as that of Example 1. The difference is that the roughened three-layer metal structure enters the induction heating furnace, the material is rapidly heated to 400°C, and then continuously enters the online heating furnace for heat preservation. The heat preservation temperature is 400°C and the heat preservation time is 6 minutes.

[0103] Example 6

[0104] The preparation method of this embodiment is basically the same as that of Example 1. The difference is that the roughened three-layer metal structure enters the induction heating furnace, the material is rapidly heated to 420°C, and then continuously enters the online heating furnace for heat preservation. The heat preservation temperature is 420°C and the heat preservation time is 2 minutes.

[0105] Example 7

[0106] The preparation method of this embodiment is basically the same as that of Example 1. The difference is that after the heat preservation is completed, a four-roll composite rolling mill is used for continuous composite rolling, with a single pass reduction rate of 50% and a composite rolling speed of 2m / min.

[0107] Example 8

[0108] The preparation method of this embodiment is basically the same as that of Example 1, except that a 200nm pure copper layer is electroplated onto the surface of the brass used.

[0109] Example 9

[0110] The preparation method of this embodiment is basically the same as that of Example 1, except that a 1000nm pure copper layer is electroplated onto the surface of the brass used.

[0111] Comparative Example 1

[0112] The preparation method of this comparative example is basically the same as that of Example 1, except that the thickness ratio of brass:aluminum:brass is 1:0.5:1 before lamination.

[0113] Comparative Example 2

[0114] The preparation method of this comparative example is basically the same as that of Example 1, except that the thickness ratio of brass:aluminum:brass is 1:10:1 before lamination.

[0115] Comparative Example 3

[0116] The preparation method of this comparative example is basically the same as that of Example 1, except that the single-pass rolling reduction rate of the solid-cold composite is 40%.

[0117] Comparative Example 4

[0118] The preparation method of this comparative example is basically the same as that of Example 1, except that the roughened three-layer metal structure is put into an induction heating furnace and the material is rapidly heated to 350°C.

[0119] Comparative Example 5

[0120] The preparation method of this comparative example is basically the same as that of Example 1, except that the roughened three-layer metal structure is put into an induction heating furnace and the material is rapidly heated to 550°C.

[0121] Comparative Example 6

[0122] The preparation method of this comparative example is basically the same as that of Example 1, except that the annealing temperature of the finished product is 300℃.

[0123] Comparative Example 7

[0124] The preparation method of this comparative example is basically the same as that of Example 1, except that the annealing temperature of the finished product is 550°C.

[0125] Test Example 1

[0126] Surface hardness testing: Using the Vickers hardness test method, a diamond pyramidal indenter (136° angle) was pressed into the material surface under a 50g load and held for 10 seconds to form an indentation. The hardness value was then calculated by measuring the diagonal length of the indentation. The surface hardness was measured at 12 different locations on both sides of the roll material, and the average value was obtained. Detailed test results for each embodiment and comparative example are shown in Table 2.

[0127] Yield strength test: The composite materials of each embodiment or comparative example were tested using a tensile testing machine. The sample was placed in a fixture, and the tensile force was gradually increased to stretch the sample, and its stress and strain were measured. The stress corresponding to the yield point in the stress-strain curve is the yield strength. Multiple samples were measured for each embodiment and comparative example, and the average value was taken. Detailed test results are shown in Table 2.

[0128] Tensile strength test: The stress value corresponding to the point of maximum tensile force during testing on a tensile testing machine is the tensile strength. Detailed test results for each embodiment and comparative example are shown in Table 2.

[0129] Elongation test: When tested on a tensile testing machine, the ratio of the change in length of the sample before and after stretching to the original length is the elongation. Detailed test results for each embodiment and comparative example are shown in Table 2.

[0130] Bond strength test: The peel strength test method in GB / T32468-2025 was used to detect whether delamination occurred after peeling. Detailed test results for each embodiment and comparative example are shown in Table 2.

[0131] IMC layer thickness range test: The samples of each embodiment and comparative example were subjected to cross-sectional SEM test. The shaded and blurred area at the junction of the two phases in the cross-sectional SEM image is the IMC layer. The thickness range of the IMC layer can be determined from the image. Figure 2 This is a cross-sectional SEM image of the brass-aluminum-brass composite material from Example 1. Figure 2 The MC layer thickness ranged from 290 to 480 nm. Test results for other embodiments and comparative examples are detailed in Table 2.

[0132] Heat dissipation performance (thermal conductivity) test: At room temperature of 25℃, the sample is made into a small disc (thickness of 3mm). The sample is uniformly irradiated with short laser pulses to raise its temperature. The temperature rise process is continuously measured with an infrared detector. The thermal diffusivity of the material can be calculated based on the temperature change over time. Then, the thermal conductivity can be calculated based on the specific heat capacity and density.

[0133] Conductivity test: At room temperature (25°C), a probe is used to contact the surface of the columnar material, a constant current is passed through it, the voltage across the material is measured, the resistance is calculated, and then converted into conductivity.

[0134] Table 1. Performance test results of composite materials in each embodiment and comparative example

[0135]

[0136] Table 2. Performance test results of composite materials in each embodiment and comparative example

[0137]

[0138] Based on the data in Tables 1 and 2 above, in Comparative Example 3, the single-pass compression rate was 40%, indicating insufficient interlayer bonding strength, resulting in delamination of the composite material during the bonding strength test. In Comparative Example 4, compared to Example 1, the heating temperature was lower, the IMC layer thickness was lower, and the yield strength of the composite material decreased. In Comparative Example 5, compared to Example 1, the heating temperature was higher, the IMC layer thickness was higher, and the average surface hardness, yield strength, and tensile strength of the composite material all decreased. In Comparative Example 1, compared to Example 1, the aluminum layer thickness was reduced, with the intermediate aluminum layer only accounting for half of the single-layer brass layer, resulting in a decrease in the yield strength of the composite material. In Comparative Example 2, compared to Example 1, the aluminum layer was ten times larger than the single-layer brass layer, and the yield strength of the composite material also decreased.

[0139] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a brass-aluminum-brass composite material by warm bonding, characterized in that, The preparation method includes the following steps: The first brass, aluminum, and second brass are heat-treated at a temperature of 400-500℃ for 2-6 minutes. The thickness ratio of the first brass, the aluminum, and the second brass is 1:(1-8):

1. The first brass and the second brass are selected from one of H58, H59, H60, H62, H62.5, H63, H65, H66, H68, H70, H80, H85, H90, H95, and H96, respectively. Materials with a post-insulation temperature of 400~500℃ are subjected to a rolling composite treatment according to a brass-aluminum-brass structure. The rolling composite treatment is a single-pass rolling process with a single-pass rolling reduction rate of 50%~70%. The temperature of the material undergoing the rolling composite treatment is reduced to room temperature; after rolling, diffusion annealing is not required, and the residual heat of the material can be used to allow the intermetallic compound at the copper-aluminum interface to diffuse, forming a discontinuous intermetallic compound layer. The material undergoing the rolling composite treatment is subjected to cold rolling to obtain a brass-aluminum-brass composite material of the target thickness, wherein the brass-aluminum-brass composite material includes an intermetallic compound layer of 200-500 nm between the brass layer and the aluminum layer.

2. The preparation method according to claim 1, characterized in that, The aluminum material is selected from one of the following: 1-series aluminum alloys, 3-series aluminum alloys, 5-series aluminum alloys, and 8-series aluminum alloys.

3. The preparation method according to claim 1 or 2, characterized in that, Before the heat treatment, the surfaces of the first brass and the second brass each comprise a pure copper layer of 200-1000 nm.

4. The preparation method according to claim 1 or 2, characterized in that, The heat treatment of the first brass, aluminum, and second brass includes: The first brass, the aluminum material, and the second brass are stacked in a brass-aluminum-brass structure and then subjected to the heat treatment.

5. The preparation method according to claim 1 or 2, characterized in that, The cold rolling process includes roughing and finishing rolling; The total reduction rate of the roughing process is 60%~70%, and the single-pass reduction rate is 15%~30%; The total reduction rate of the finishing rolling process is 60%~70%, and the single-pass reduction rate is 15%~30%.

6. The preparation method according to claim 5, characterized in that, The preparation method further includes: After rough rolling, intermediate annealing is performed at a temperature of 350~450℃. After the finishing rolling, the finished product is annealed at a temperature of 350~450℃.

7. A brass-aluminum-brass composite material, characterized in that, The brass-aluminum-brass composite material is prepared by the preparation method according to any one of claims 1-6, wherein the thickness ratio of the brass layer, the aluminum layer and the brass layer in the brass-aluminum-brass composite material is 1:(1~8):1; An intermetallic compound layer of 200-500 nm is included between the brass layer and the aluminum layer.

8. An LED bracket, characterized in that, The LED bracket is prepared using the brass-aluminum-brass composite material described in claim 7.

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