High-toughness magnesium / aluminum composite board material and preparation method thereof

Abstract

The invention provides a magnesium / aluminum composite plate material and a preparation method thereof. According to the preparation method, a rare earth magnesium alloy plate and an aluminum alloy plate are prepared into the magnesium / aluminum composite plate material through a multi-pass liner plate accumulative ply rolling method. Compared with the prior art, the method has the advantages that shear stress is converted into pressure stress by adopting a lining plate rolling compounding method, so that edge cracks and cracks are effectively inhibited, and the formability of the material is improved; meanwhile, the recrystallization process is promoted, the work hardening is retarded, and the residual stress is reduced; furthermore, relatively large rolling reduction and high ply rolling times are realized, and interface bonding and structure homogenization and refinement are promoted; meanwhile, the method has the advantages of simple process, low production cost and high material utilization rate.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of metal matrix composite materials, relates to a magnesium / aluminum composite plate material, and specifically relates to a high-strength and toughness magnesium / aluminum composite plate material and a preparation method thereof. Background Art

[0002] Magnesium alloys have the advantages of low density, high specific strength, high specific stiffness and excellent damping performance, making them ideal lightweight structural materials. However, traditional magnesium alloys have low absolute strength, poor plasticity and insufficient corrosion resistance, which still greatly limits their application.

[0003] As a severe plastic deformation technology, cumulative rolling technology has the advantages of simple process, high production efficiency and easy large-scale production. After multiple rolling passes, a large cumulative strain can be obtained, and a layered composite material with uniform, fine structure and high interface bonding strength can be prepared. However, due to the poor plasticity of magnesium alloys, edge cracks of the plate are easily caused during the rolling process, thereby reducing the yield rate. In addition, rolling shear stress can cause internal cracks in magnesium alloys and even cause material fracture, reducing the plasticity of the composite plate. Furthermore, due to the influence of work hardening and residual stress, a large rolling reduction and a high number of rolling cycles are difficult to achieve, which is the key to ensuring high bonding strength and grain refinement to achieve high strength and toughness. Summary of the invention

[0004] In view of the deficiencies in the prior art, the object of the present invention is to provide a high-strength and toughness magnesium / aluminum composite plate material and a preparation method thereof, so as to solve the technical problem that the strength and toughness of the magnesium / aluminum composite plate material prepared by cumulative rolling in the prior art need to be further improved.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve the above problems:

[0006] A method for preparing a magnesium / aluminum composite plate material comprises the following steps: using a rare earth magnesium alloy plate and an aluminum alloy plate to form the magnesium / aluminum composite plate material through a multi-pass liner accumulation rolling method.

[0007] The present invention also has the following technical features:

[0008] Specifically, the rare earth magnesium alloy is made of the following elements by weight: Gd is 6.0% to 15.0%, Y is 1.5% to 4.5%, Zn is 0.5% to 2%, Zr is 0.2% to 0.7%, impurity elements are 0.01% to 0.05%, and the remainder is Mg. The sum of the weight percentages of the elements is 100%.

[0009] Specifically, the rare earth magnesium alloy is made of the following elements by weight: 8.92% Gd, 3.1% Y, 1.92% Zn, 0.32% Zr, 0.05% impurity elements, and 85.69% Mg.

[0010] Preferably, the liner in the multi-pass liner cumulative rolling is a cemented carbide liner.

[0011] The hard alloy liner is a steel plate.

[0012] Specifically, the preparation method comprises the following steps:

[0013] Step 1: Preprocessing:

[0014] The rare earth magnesium alloy sheet and the aluminum alloy sheet are subjected to surface treatment, stacking, punching and riveting to obtain riveted sheets.

[0015] Step 2: Liner rolling and lamination:

[0016] A hard alloy liner is added to the upper and lower surfaces of the riveted plate obtained in step 1, and after heating, the plate is rolled and composited to a specified rolling reduction to obtain an initial composite plate.

[0017] In step 2, the heating temperature is 150-400° C., and the insulation time is 5-30 minutes.

[0018] Step 3: Multiple passes of liner accumulation and rolling:

[0019] The initial composite plate obtained in step 2 is cut, surface treated, stacked, punched and riveted, and multiple lining plates are cumulatively rolled after adding lining plates to finally obtain a magnesium / aluminum composite plate material.

[0020] In step three, the heating temperature of the cumulative rolling of the multiple liner plates is 150-400° C., and the insulation time is 5-30 minutes.

[0021] Specifically, in step 1, the pretreatment specifically includes the following steps:

[0022] Step 101, grinding the surfaces of the rare earth magnesium alloy sheet and the aluminum alloy sheet to be composited with a steel brush in a direction parallel to the rolling direction until the oxide layer is removed and the roughness is uniform.

[0023] Step 102, cleaning the polished rare earth magnesium alloy plate and aluminum alloy plate obtained in step 101 with alcohol / acetone, and drying them.

[0024] Step 103, stacking the clean rare earth magnesium alloy sheet and aluminum alloy sheet obtained in step 102, punching holes at the front end, and riveting them together with rivets to obtain riveted sheets, which are placed in a clean environment for standby use.

[0025] Preferably, in step 2, the surfaces of the riveted plate in contact with the cemented carbide liner are coated with a high-temperature isolation agent.

[0026] Specifically, in step 2, the thickness of the cemented carbide lining plate is 0.1-2 mm, the width of the cemented carbide lining plate is greater than the width of the initial composite plate, and the length of the cemented carbide lining plate is greater than the length of the initial composite plate.

[0027] Preferably, in step 2, the rolling speed of the rolling composite is 200 to 500 mm / s.

[0028] In step 2, the rolling reduction is 30% to 70%.

[0029] In step three, the rolling speed of the multiple-pass liner cumulative rolling is 200-500 mm / s.

[0030] In step three, the cumulative rolling reduction of the multiple liner rolling is 30% to 70%.

[0031] The present invention also protects a magnesium / aluminum composite plate material, which is prepared by the method for preparing the magnesium / aluminum composite plate material as described above.

[0032] Compared with the prior art, the present invention has the following technical effects:

[0033] (I) Compared with the prior art, the present invention adopts a liner rolling composite method to convert shear stress into compressive stress, effectively suppressing edge cracks and cracks and improving the formability of the material; at the same time, it promotes the recrystallization process, slows down work hardening and reduces residual stress; further, it achieves a larger rolling reduction and a high number of overlapping rolling passes, promotes interface bonding and microstructure homogenization and refinement; at the same time, the method also has the advantages of simple process, low production cost and high material utilization.

[0034] (II) In the process of multiple liner rolling and compounding of the rare earth magnesium alloy plate and the aluminum alloy plate in the present invention, the compressive stress promotes the interface bonding and recrystallization process. In addition, after multiple liner cumulative rolling, the interface intermetallic compounds are fragmented, the interface bonding strength is significantly improved, and the microstructure is refined. The prepared magnesium / aluminum composite plate material has a layered heterogeneous configuration, good interface bonding and uniform and fine grain structure, so that the magnesium / aluminum composite plate material maintains high strength while also having good toughness, achieving strength-toughness matching.

[0035] (III) The present invention adopts a multi-pass liner cumulative rolling method, taking into account factors such as rolling temperature, while ensuring the high strength of the magnesium / aluminum composite plate material, taking into account the improvement of toughness, optimizing the mechanical properties of the magnesium / aluminum composite plate material, and making the functional characteristics between the components complementary, greatly expanding the application range of the magnesium / aluminum composite plate material. At the same time, the preparation method of the magnesium / aluminum composite plate material in the present invention is also applicable to the preparation of other metal composite plate materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The present invention is a process flow chart of a method for preparing a high-strength and tough magnesium / aluminum composite plate material.

[0037] The specific contents of the present invention are further explained in detail below in conjunction with embodiments. DETAILED DESCRIPTION

[0038] It should be noted that all raw materials and instruments in the present invention, unless otherwise specified, are all raw materials and instruments known in the prior art. For example, the rare earth magnesium alloy plate adopts the known rare earth magnesium alloy plate, and the steel plate adopts the known commercially available steel plate.

[0039] The technical idea of ​​the present invention is that the absolute strength of traditional magnesium alloys is low, and their applications are greatly limited. In contrast, rare earth magnesium alloys have enhanced the effects of fine grain and solid solution strengthening and weakened the texture through the introduction of rare earth elements, and have more outstanding mechanical properties. They have broad application prospects in the fields of aerospace, national defense, military industry, and rail transportation. However, rare earth magnesium alloys still have the problems of poor plasticity and insufficient corrosion resistance, while aluminum alloys have more excellent plasticity, toughness and corrosion resistance, and the application fields of rare earth magnesium alloys complement and intersect each other. The combination of the two can combine their advantages and make up for the shortcomings. Layered heterogeneous materials combine the characteristics of heterogeneous configurations and layer interfaces. During deformation, stress / strain redistribution can be achieved to delay local necking of the material; in addition, the layer interface can be used to inhibit crack expansion and change its expansion path, significantly improving the plasticity of the material; furthermore, the deformation incompatibility between heterogeneous materials can achieve geometric dislocation accumulation at the interface, thereby achieving a synergistic improvement in strength and toughness. Therefore, by configuration design and component selection, magnesium / aluminum composite plate materials are prepared with rare earth magnesium alloy plates and aluminum alloy plates as raw materials, which not only effectively improves the mechanical properties of the materials, but also improves their corrosion resistance, which will greatly expand the application range of the two materials. Cumulative rolling, as a severe plastic deformation technology for preparing large-scale layered composite materials, can obtain high-performance composite plate materials with uniform and fine structures and strong interface bonding. However, when traditional cumulative rolling is used to prepare magnesium / aluminum composite plate materials, there are problems such as severe edge cracking, easy crack initiation, and limited reduction and number of rolling passes. In response to this, the present invention provides a method for preparing composite plate materials that effectively alleviates edge cracking, improves material forming performance, rolling reduction and number of rolling passes.

[0040] In the present invention, the number of times of rolling the liner plate for rolling and bonding is multiple times means that if the specified rolling reduction is 50%, the rolling can be performed multiple times. For example, when rolling is performed twice, the rolling reduction of the first liner plate rolling and bonding can be 20%, and the rolling reduction of the second liner plate rolling and bonding can be 30%, and the total rolling reduction can be 50%.

[0041] In the present invention, the cumulative rolling of multiple liner plates refers to cutting the plate in half and stacking it after rolling one pass, and then rolling it again. The rolled plate is then cut in half and stacked again, and then rolled again. The cycle is repeated, which is the cumulative rolling of multiple liner plates.

[0042] The high-strength and toughness magnesium / aluminum composite plate material in the present invention refers to a magnesium / aluminum composite plate material prepared by cumulative rolling, which has a tensile strength greater than 330 MPa and an elongation greater than 8%.

[0043] In the present invention, the impurity element is one or a combination of more than one of Fe, Cu and Ni.

[0044] In accordance with the above technical scheme, specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical scheme of this application fall within the protection scope of the present invention.

[0045] Embodiment 1:

[0046] This embodiment provides a method for preparing a high-strength and tough magnesium / aluminum composite plate material. The method is to use a rare earth magnesium alloy plate and an aluminum alloy plate to prepare the magnesium / aluminum composite plate material through a multi-pass liner accumulation rolling method.

[0047] The rare earth magnesium alloy is made of the following elements, in parts by weight: 8.92% Gd, 3.1% Y, 1.92% Zn, 0.32% Zr, 0.05% impurity elements, and 85.69% Mg.

[0048] In this embodiment, the thickness of the rare earth magnesium alloy plate is 1.5 mm.

[0049] In this embodiment, the grade of the aluminum alloy plate is 1060, and the thickness of the aluminum alloy plate is 1 mm.

[0050] In this embodiment, the liner in the multi-pass liner cumulative rolling is a steel plate with a thickness of 1 mm, a width of the steel plate greater than the width of the initial composite plate, and a length of the steel plate greater than the length of the initial composite plate.

[0051] The preparation method specifically comprises the following steps:

[0052] Step 1: Preprocessing:

[0053] like Figure 1 As shown, the rare earth magnesium alloy sheet and the aluminum alloy sheet are subjected to surface treatment, stacking, punching and riveting to obtain the riveted sheet.

[0054] In step 1, the preprocessing specifically includes the following steps:

[0055] Step 101, grinding the surfaces of the rare earth magnesium alloy sheet and the aluminum alloy sheet to be composited with a steel brush in a direction parallel to the rolling direction until the oxide layer is removed and the roughness is uniform.

[0056] Step 102, cleaning the polished rare earth magnesium alloy plate and aluminum alloy plate obtained in step 101 with alcohol / acetone, and drying them.

[0057] Step 103, stacking the clean rare earth magnesium alloy sheet and aluminum alloy sheet obtained in step 102, punching holes at the front end, and riveting them together with rivets to obtain riveted sheets, which are placed in a clean environment for standby use.

[0058] Step 2: Liner rolling and lamination:

[0059] A hard alloy liner is added to the upper and lower sides of the riveted plate obtained in step 1 and fixed by binding, and then rolled and composited to a specified rolling reduction after heating to obtain an initial composite plate.

[0060] In step 2, a muffle furnace is used for heating, the heating temperature is 250° C., and the insulation time is 10 min.

[0061] In step 2, the surfaces of the plate in contact with the cemented carbide liner after riveting are coated with a high-temperature isolating agent, which is boron nitride.

[0062] In step 2, the rolling speed of the rolling composite is 400 mm / s.

[0063] In step 2, the rolling reduction is 50%.

[0064] In this embodiment, the liner plate rolling composite rolling pass is a single-pass rolling or a multi-pass rolling.

[0065] Step 3: Multiple passes of liner accumulation and rolling:

[0066] The initial composite plate obtained in step 2 is cut, surface treated, stacked, punched and riveted, and multiple lining plates are cumulatively rolled after adding lining plates to finally obtain a magnesium / aluminum composite plate material.

[0067] In step 3, the heating temperature for the cumulative rolling of multiple liner plates is 250°C, and the holding time is 10 minutes.

[0068] In step 3, the rolling speed of the multi-pass liner cumulative rolling is 400 mm / s.

[0069] In step 3, the cumulative rolling reduction of the liner in multiple passes is 50%.

[0070] In this embodiment, the multiple-pass liner cumulative rolling is specifically two-pass liner cumulative rolling.

[0071] The magnesium / aluminum composite plate material obtained in this embodiment was tested and analyzed, and the ultimate tensile strength was measured to be 351.3 MPa, and the elongation was 9.9%.

[0072] Embodiment 2:

[0073] This embodiment provides a method for preparing a high-strength and tough magnesium / aluminum composite plate material. The preparation method is basically the same as the preparation method in Example 1, except that in step 2, the heating temperature is 300°C.

[0074] The magnesium / aluminum composite plate material obtained in this embodiment was tested and analyzed, and the ultimate tensile strength was measured to be 354.6 MPa, and the elongation was 12.7%.

[0075] Embodiment 3:

[0076] This embodiment provides a method for preparing a high-strength and toughness magnesium / aluminum composite plate material. The preparation method is basically the same as the preparation method in Example 1, except that in step 2, the heating temperature is 350°C.

[0077] The magnesium / aluminum composite plate material obtained in this embodiment was tested and analyzed, and the ultimate tensile strength was measured to be 371.5 MPa, and the elongation was 15.0%, achieving a good strength-plasticity match.

Claims

1. A method for preparing a magnesium / aluminum composite plate material, characterized in that: The preparation method is to prepare the magnesium / aluminum composite plate material by using a rare earth magnesium alloy plate and an aluminum alloy plate through a multi-pass liner accumulation lamination rolling method.

2. The method for preparing the magnesium / aluminum composite plate material according to claim 1, characterized in that: The rare earth magnesium alloy is made of the following elements by weight: Gd is 6.0% to 15.0%, Y is 1.5% to 4.5%, Zn is 0.5% to 2%, Zr is 0.2% to 0.7%, impurity elements are 0.01% to 0.05%, and the balance is Mg. The sum of the weight percentages of the elements is 100%.

3. The method for preparing the magnesium / aluminum composite plate material according to claim 2, characterized in that: The rare earth magnesium alloy is made of the following elements by weight: Gd is 8.92%, Y is 3.1%, Zn is 1.92%, Zr is 0.32%, impurity elements are 0.05%, and Mg is 85.69%.

4. The method for preparing the magnesium / aluminum composite plate material according to claim 1, characterized in that: The liner in the multi-pass liner cumulative rolling is a hard alloy liner; The hard alloy liner is a steel plate.

5. The method for preparing the magnesium / aluminum composite plate material according to claim 1, characterized in that: The preparation method specifically comprises the following steps: Step 1: Preprocessing: Surface treatment, stacking, punching and riveting are performed on rare earth magnesium alloy plates and aluminum alloy plates to obtain riveted plates; Step 2: Liner rolling and lamination: Adding hard alloy lining plates on the upper and lower sides of the riveted plate obtained in step 1, heating and rolling the plate to a specified rolling reduction to obtain an initial composite plate; In step 2, the heating temperature is 150-400° C., and the insulation time is 5-30 min; Step 3: Multiple passes of liner accumulation and rolling: The initial composite plate obtained in step 2 is cut, surface treated, stacked, punched and riveted, and multiple liner accumulation rolling is performed after adding liner plates, and finally a magnesium / aluminum composite plate material is obtained; In step three, the heating temperature of the cumulative rolling of the multiple liner plates is 150-400° C., and the insulation time is 5-30 minutes.

6. The method for preparing the magnesium / aluminum composite plate material according to claim 5, characterized in that: In step 1, the pretreatment specifically includes the following steps: Step 101, grinding the surfaces of the rare earth magnesium alloy sheet and the aluminum alloy sheet to be composited with a steel brush in a direction parallel to the rolling direction until the oxide layer is removed and the roughness is uniform; Step 102, cleaning the polished rare earth magnesium alloy plate and aluminum alloy plate obtained in step 101 with alcohol / acetone and drying them; Step 103, stacking the clean rare earth magnesium alloy sheet and aluminum alloy sheet obtained in step 102, punching holes at the front end, and riveting them together with rivets to obtain riveted sheets, which are placed in a clean environment for standby use.

7. The method for preparing the magnesium / aluminum composite plate material according to claim 5, characterized in that: In step 2, the surfaces of the riveted plate in contact with the cemented carbide liner are coated with a high-temperature isolation agent.

8. The method for preparing the magnesium / aluminum composite plate material according to claim 5, characterized in that: In step 2, the thickness of the cemented carbide lining plate is 0.1-2 mm, the width of the cemented carbide lining plate is greater than the width of the initial composite plate, and the length of the cemented carbide lining plate is greater than the length of the initial composite plate.

9. The method for preparing the magnesium / aluminum composite plate material according to claim 5, characterized in that: In step 2, the rolling speed of the rolling composite is 200-500 mm / s; In step 2, the rolling reduction is 30% to 70%; In step 3, the rolling speed of the multi-pass liner cumulative rolling is 200-500 mm / s; In step three, the cumulative rolling reduction of the multi-pass liner is 30% to 70%.

10. A magnesium / aluminum composite plate material, characterized in that: The magnesium / aluminum composite plate material is prepared by the method for preparing the magnesium / aluminum composite plate material according to any one of claims 1 to 9.

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