Lightweight high-strength high-damping aluminum-zinc-based composite board and preparation method thereof

Abstract

The invention discloses a light-weight high-strength high-damping aluminum-zinc-based composite board and a preparation method thereof, and the light-weight high-strength high-damping aluminum-zinc-based composite board is obtained by alternately stacking an aluminum alloy plate and a zinc plate, rolling by using a cold rolling mill under the condition that the deformation amount is not less than 70%, and then carrying out multi-pass accumulative ply rolling by using the deformed board. The method is simple in process and low in cost, the damping performance and mechanical performance of the light metal-based damping material at the temperature close to the room temperature are greatly improved, the requirement for function integration of structural materials in the near-room-temperature vibration and noise reduction application field can be well met, and the method is particularly suitable for the high-tech fields requiring low density and high performance such as space flight and aviation.

Description

Technical Field

[0001] The invention belongs to the field of metal material processing and relates to a high-performance aluminum-zinc-based composite plate and a preparation method thereof. Background Art

[0002] With the rapid development of modern industry, the accompanying vibration and noise problems are becoming more and more serious. Especially in the context of modern industry seeking more functional applications of lightweight materials, the development of new high-damping alloys that can effectively dissipate vibration energy has become a pressing issue. In recent years, Al-Zn alloys have been widely used due to their good formability, high strength-to-weight ratio, and excellent damping capacity. However, the improvement of the damping capacity of materials is usually accompanied by a decrease in mechanical properties, and the low strength of Al-Zn alloys limits their application in some specific fields that are sensitive to vibration and noise. Therefore, it is urgent to find methods and related mechanisms to simultaneously improve the damping capacity and mechanical properties of aluminum-zinc alloys.

[0003] The existing technology mainly prepares aluminum-zinc alloys by casting. The alloys obtained by this method usually have high damping capacity, but there are two main problems: (1) the grains in the alloy are relatively coarse, resulting in relatively low mechanical properties (strength and plasticity); (2) defects in the metal crystals also affect the metal's damping performance. By effectively refining the internal grains of aluminum-zinc alloys, the mechanical properties and damping properties of aluminum-zinc alloys can be improved at the same time, further expanding the application field of aluminum-zinc alloys.

[0004] Cumulative rolling technology can achieve a large deformation that is not easy for the material itself to achieve while maintaining the cross-sectional shape and area of ​​the material unchanged. Cumulative rolling is a process of multiple rolling and compounding of plates. Theoretically, it can be repeated indefinitely, so that the structure of the material is refined and the mechanical properties of the material are greatly improved. At the same time, the cost of cumulative rolling is low and the process is simple, and it is expected to achieve large-scale industrial continuous production. Patent CN111085544A discloses a method for preparing high-strength and high-toughness aluminum alloy plates by rolling. Aluminum alloy plates of different thicknesses are combined together by rolling, arranged in a gradient, and a high-strength and high-toughness aluminum alloy plate with a gradient structure is obtained, indicating that the aluminum alloy has good processing performance. Patent CN101319333A discloses a titanium / aluminum composite plate and a preparation method thereof. It prepares an aluminum-titanium-aluminum three-layer composite plate by hot rolling, but the high strength of the titanium alloy makes it impossible to achieve it through a cold rolling process, and the high-temperature heat treatment process will cause surface oxidation and decreased bonding strength, and there are problems of complex process and high cost. Patent CN117206327A discloses an aluminum-zinc single-sided and double-sided composite plate and strip and its manufacturing equipment and process. The aluminum-zinc single-sided and double-sided composite plate and strip are obtained by composite rolling of the aluminum plate layer and the zinc plate layer on both sides, so that the advantages of the two materials of aluminum and zinc are maximized, but it is only rolled once. Patent CN118664974A discloses a method for preparing a magnesium / aluminum layered composite plate with both high modulus and high damping. The aluminum plate / magnesium plate / aluminum plate are riveted and assembled in sequence, and metal powder is added between magnesium and aluminum, and at least three layers of cumulative rolling are performed in a heated environment. This process also has the problems of severe surface oxidation caused by heating, poor interface bonding strength, and low yield. Summary of the invention

[0005] Based on the shortcomings of the above-mentioned prior art, the present invention provides a method for preparing a lightweight, high-strength, high-damping aluminum-zinc-based composite sheet, which aims to achieve lightweight composite materials by increasing the volume ratio of the aluminum alloy layer, effectively refine the internal grains of the aluminum alloy layer at room temperature to improve the mechanical properties of the composite materials, and maintain the high damping performance of the Al-Zn composite sheet through the high-density dislocation of the pure Zn layer. The composite material obtained by this heterogeneous structure design can achieve simultaneous optimization of the mechanical properties and damping properties of the material, realize structural and functional integration, and further expand the application field of traditional materials.

[0006] In order to achieve the above object, the present invention adopts the following technical scheme:

[0007] A method for preparing a lightweight, high-strength, high-damping aluminum-zinc-based composite sheet is characterized in that it is prepared by a cumulative rolling method and comprises the following steps:

[0008] Step 1: Calculate the required thickness ratio of aluminum alloy sheet and pure zinc sheet by the density requirement of the target aluminum-zinc composite sheet. The stacking method of aluminum alloy sheet and pure zinc sheet is two aluminum alloy sheets on both sides and a pure zinc sheet in the middle. Assuming that the density requirement of the target aluminum-zinc composite sheet is ρ, the two aluminum alloy sheets are made of equal thickness, and the thickness ratio of each aluminum alloy sheet to the pure zinc sheet is χ. It is known that the density of aluminum alloy is about 2.8g / cm 3 , the density of zinc is 7.1g / cm 3 According to the formula: The thickness ratio χ is calculated.

[0009] Step 2: Cut the aluminum alloy sheet and pure zinc sheet to be accumulated and rolled into equal length and width sizes, and then clean the surface.

[0010] Step 3: Grinding the stacked contact surfaces of the cleaned aluminum alloy plates and pure zinc plates, and then stacking the plates in the structural order of aluminum alloy / zinc / aluminum alloy to form initial stacked plates.

[0011] Step 4: performing a first rolling process on the initial stacked plates, with a deformation amount of not less than 70%, to form a three-layer structured stacked plate.

[0012] Step 5: Two groups of 3×2 n-2 After the stacking contact surface of the layer structure stacked plates is polished, the stack is aligned and rolled for the nth time, with a deformation of not less than 50%, to form a 3×2 n-1 Layer structure stacked panels;

[0013] n is taken as integers from 2 to m in sequence, and the second to mth passes of rolling are performed, 3≤m≤6.

[0014] Step 6: Perform m passes of rolling to obtain 3×2 m-1 The layer structure plate is the required lightweight, high-strength and high-damping aluminum-zinc based composite plate.

[0015] Furthermore, in step 2: cleaning can be performed using an ultrasonic cleaning machine and anhydrous ethanol to remove oil stains on the surface of the metal plate due to wire cutting, which is beneficial to subsequent rolling and compounding.

[0016] Furthermore, in step 3 and step 5: use a wire brush or 400# or less coarse sandpaper to evenly polish the plate surface to improve the surface roughness and improve the interface bonding effect during rolling. The polishing degree is until the oxide film or hardened layer on the surface of the plate is removed, and the purpose is to expose the fresh metal on the surface of the plate;

[0017] Furthermore, in step 4: the deformation amount of the first rolling is not less than 70% to improve the rolling bonding effect and avoid separation between layers of the composite plate.

[0018] Furthermore, between two adjacent rolling passes: the shape of the rolled plate of the previous pass is adjusted, and the edge portion of the cracks of the previous rolling is removed, otherwise the cracks will extend during the rolling process and affect the next rolling result; the time interval between surface grinding and rolling is kept within 150 seconds to avoid the re-formation of the surface oxide layer. If the interval time is longer, the plate surface needs to be re-grinded.

[0019] The present invention uses pure Zn plate and aluminum alloy plate (such as 6061Al plate in the embodiment) to successfully manufacture a multilayer Al / Zn composite plate through the accumulative rolling bond (ARB) technology. The process is simple and the cost is low. It can greatly improve the damping performance and mechanical properties of lightweight metal-based damping materials near room temperature, and can well meet the requirements of structural materials in the field of vibration reduction and noise reduction near room temperature. It is particularly suitable for high-tech fields such as aerospace that require low density and high performance. The beneficial effects of the process adopted by the present invention are specifically embodied in:

[0020] 1. Room temperature rolling is convenient, efficient and has low production cost. No high-temperature heat treatment is required before and after cold rolling. During the high-speed cold rolling and large plastic deformation process, the pure zinc layer has achieved dynamic recrystallization during the first rolling, while the aluminum alloy layer will not undergo dynamic recrystallization until multiple rolling passes. The aluminum alloy layer can achieve deformation strengthening effects, so the entire composite sheet can achieve high strength and high damping performance. In addition, a belt sandpaper grinder is used for double-sided or single-sided grinding, followed by double-roll cold rolling, which does not involve vacuum and high-temperature heat treatment, so large-scale production of aluminum-based high-damping sheets can be achieved with low cost and high efficiency.

[0021] 2. During the multiple rolling process, the damping capacity of the obtained composite plate is significantly improved. Taking 6061Al and Zn in the embodiment as an example, the room temperature damping of the plate increases first and then decreases with the increase of the number of cycles through the amplitude internal friction spectrum test. Among them, ARB3 has the largest room temperature damping, which is 1 Hz at a frequency of 400×10 -6 The room temperature damping of ARB3 reaches 0.06. Generally speaking, the improvement of damping capacity comes from the special structure inside the pure zinc layer, including high dislocation density, elongated lamellar grains and a high proportion of low-angle grain boundaries (LAGBs).

[0022] 3. During the multiple rolling process, the strength of the obtained composite sheet is significantly improved. Taking 6061Al and Zn in the embodiment as an example, with the increase of ARB cycles, the elongation of the ARB sample first increases and then decreases, while the ultimate tensile strength continues to increase. The strength of ARB6 reaches 300MPa. The improvement in the mechanical properties of the ARB sample can be attributed to the fine grain strengthening effect of the aluminum alloy layer and the hindering effect of the high-density interface on dislocation movement. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the ARB process of the 6061Al / Zn multilayer composite plate in an embodiment of the present invention;

[0024] Figure 2 The scanning electron microscope images of the composite plates obtained by different rolling passes are shown in Figure 2. Figure 2 (a) is the SEM photo of the first rolled plate. Figure 2 (b) is the SEM photo of the plate after three rolling processes. Figure 2 (c) is the SEM image of the plate rolled five times.

[0025] Figure 3 Damping-amplitude curve of the composite plate obtained with different rolling passes (vibration frequency 1 Hz).

[0026] Figure 4 Stress-strain curves of composite plates obtained with different rolling passes. DETAILED DESCRIPTION

[0027] The present invention is described in detail below with reference to specific embodiments.

[0028] Example 1

[0029] This embodiment provides a lightweight, high-strength, high-damping aluminum-zinc based composite plate, such as Figure 1 As shown, the preparation method thereof comprises the following steps:

[0030] Step 1: The overall density of the target aluminum-zinc composite plate is required to be 4.18 g / cm 3 The stacking method of the aluminum alloy plate and the pure zinc plate is two aluminum alloy plates and one pure zinc plate. It is calculated that the thickness ratio of each aluminum alloy plate and the pure zinc plate is about 1:1. At this time, the mass ratio of the two plates in the composite plate is 44% 6061Al-56% Zn.

[0031] Step 2, surface treatment: Since the plate has not been homogenized annealing treatment before leaving the factory, in order to ensure the subsequent interface bonding, the metal plate is first annealed. The annealing temperature of the pure Zn plate is 150℃, the holding time is 0.5h, and it is cooled with the furnace; the annealing temperature of the 6061Al plate is 350℃, the holding time is 1h, and it is cooled with the furnace. Use an ultrasonic cleaning machine to ultrasonically clean the two plates with anhydrous ethanol to remove the oil stains on the surface of the metal plate due to wire cutting.

[0032] Step 3: Stacking and fixing: Grind the stacking contact surfaces of the cleaned aluminum alloy plates and pure zinc plates until the oxide film or hardened layer on the plate surface is removed and the surface looks rough. Next, stack the metal plates that have completed the surface treatment in the order of 6061Al / Zn / 6061Al "sandwich" structure to form the initial stacking plates.

[0033] Step 4, first rolling: The initial stacked plates are rolled for the first time, using a cold rolling mill with a rolling speed of 6 mm / min. The thickness of the composite plate decreases from the original 3 mm to about 1 mm. After the first rolling, the total thickness of the composite plate decreases by about 79%. A high reduction is a necessary condition to ensure good adhesion between adjacent metal layers. The first rolling pass is defined as 1 pass, and the plate is recorded as ARB1. Multiple ARB1 plates are rolled continuously.

[0034] Step 5: Accumulative rolling: For two groups of 3×2 n-2 After the stacking contact surface of the layer structure stacked plates is polished, the stack is aligned and the nth rolling is performed with a deformation of about 55% to form a 3×2 n-1 The plate is stacked in a layer structure; n is taken as an integer from 2 to 6 in sequence, and the rolling is performed from the 2nd to the 6th pass.

[0035] Step 6: The composite plate is cumulatively rolled for 6 ARB cycles (samples are denoted as ARB1-ARB6), and the composite plates obtained by rolling 1-6 passes have 3, 6, 12, 24, 48, and 96-layer structures, respectively.

[0036] In the above method, the time interval between surface grinding and rolling is kept within 150 seconds to avoid the re-formation of the surface oxide layer. Theoretically, ARB can be cycled an unlimited number of times, but during the cyclic rolling process, the composite plate will have unbonded interfaces, poor bonding quality, and cracking at the edges of the plate. These factors limit the rolling and bonding of the composite plate at high passes, and too high a pass may lead to a decrease in the damping performance of the plate. Therefore, there is an optimal rolling pass for the mechanical-damping properties of the composite plate.

[0037] Figure 2 The scanning electron microscope images of the composite plates obtained by different rolling passes show that with the increase of ARB cycles, the number of metal layers increases and the thickness of each layer decreases. The interface is continuous and well bonded.

[0038] Figure 3 The damping-amplitude curves of the composite plates obtained with different rolling passes (vibration frequency 1 Hz). It can be seen that ARB3 has a damping-amplitude curve of 10×10 -6 to 800×10 -6 The damping capacity within the range is significantly improved, with an amplitude of 400×10 -6 The ARB3 damping is as high as 0.06.

[0039] Figure 4The stress-strain curves of the composite plates obtained by different rolling passes show that the strength of ARB6 is 300MPa; ARB3 has the best comprehensive mechanical properties, with a strength of about 250MPa and an elongation of about 11%.

[0040] This embodiment finally obtained a composite material with a composition of 44wt% 6061Al-56wt% Zn, and a density of 4.18g / cm 3 , achieving the goal of light weight, high strength and high damping. The best pass for comprehensive mechanical damping performance is 3 passes. The optimal pass is related to the thickness ratio of the two metal layers in the composite plate.

[0041] The above embodiments are only preferred implementation modes of the present invention, but the present invention is not limited to the above embodiments. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essential content of the present invention belong to the protection scope of the present invention.

Claims

1. A method for preparing a lightweight, high-strength, high-damping aluminum-zinc based composite sheet, characterized in that: The method is prepared by cumulative rolling, comprising the following steps: Step 1: Calculate the required thickness ratio of the aluminum alloy sheet and the pure zinc sheet according to the density requirement of the target aluminum-zinc-based composite sheet; Step 2: Cut the aluminum alloy sheet and pure zinc sheet to be accumulated and rolled into equal length and width, and then clean the surface; Step 3, grinding the stacked contact surfaces of the cleaned aluminum alloy plate and the pure zinc plate, and then stacking the plates in the structural order of aluminum alloy / zinc / aluminum alloy to form an initial stacked plate; Step 4, performing a first rolling process on the initial stacked plates, with a deformation amount of not less than 70%, to form a three-layer structure stacked plate; Step 5: Two groups of 3×2 n-2 After the stacking contact surface of the layer structure stacked plates is polished and aligned, the nth rolling is performed with a deformation of not less than 50% to form a 3×2 n-1 Layer structure stacked panels; n is taken as integers from 2 to m in sequence, and the rolling is performed from the second pass to the mth pass, 3≤m≤6; Step 6: Perform m passes of rolling to obtain 3×2 m-1 The plate with a layer structure is the required lightweight, high-strength and high-damping aluminum-zinc based composite plate.

2. A lightweight, high-strength, high-damping aluminum-zinc based composite sheet material prepared by the preparation method of claim 1.

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