Aluminum alloy composite board as well as preparation method and application thereof

Abstract

The invention discloses an aluminum alloy composite board and a preparation method and application thereof. The aluminum alloy composite board comprises a first aluminum alloy layer and a second aluminum alloy layer which are connected in sequence. The aluminum alloy composite board has attractiveness and high mechanical strength, and high peel strength exists between the first aluminum alloy layer and the second aluminum alloy layer.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloys, and in particular to an aluminum alloy composite plate material and a preparation method and application thereof. Background Art

[0002] Aluminum alloy has a relatively low density, low price, medium hardness, and certain corrosion resistance. At present, the application of aluminum alloy sheets in the field of electronic products is mainly used as exterior shell parts (generally, the product shell is protected by CNC processing grooves in 6-15mm thick sheets, and electronic components are installed in the grooves). During the application process, the exterior surface will be oxidized to improve its corrosion resistance and aesthetics. Depending on the type of aluminum alloy used, there are generally 6 series aluminum alloys with a strength of 300-400MPa and a relatively beautiful oxidation effect, or 7 series aluminum alloys with a higher strength of 400-500MPa but slightly worse aesthetics after oxidation. When the industry uses 6 and 7 series aluminum alloys as exterior parts of electronic products, in order to ensure the aesthetics after oxidation, it is generally solved by reducing the addition of alloying elements and high solid solution. Therefore, aesthetics and strength conflict with each other and it is difficult to take both into account.

[0003] Therefore, it is necessary to develop an aluminum alloy sheet that has both aesthetics and strength. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the first aspect of the present invention provides an aluminum alloy composite plate material, which can take into account both mechanical strength and aesthetics.

[0005] The second aspect of the present invention also provides a method for preparing an aluminum alloy composite plate.

[0006] The third aspect of the present invention also provides an application of an aluminum alloy composite plate material.

[0007] According to a first aspect of the present invention, an aluminum alloy composite plate is provided, wherein the aluminum alloy composite plate comprises a first aluminum alloy layer and a second aluminum alloy layer connected in sequence;

[0008] In terms of mass percentage, the components of the first aluminum alloy layer include Si: 0.4% to 1.2%, Fe≤0.1%, Cu: 0.4% to 1.1%, Mn≤0.1%, Mg: 0.7% to 1.2%, Cr≤0.1%, Zn: 0.1 to 0.25%, the total amount of other impurities is <0.1%, and the balance is Al;

[0009] In terms of mass percentage, the components of the second aluminum alloy layer include Si≤0.2%, Fe≤0.4%, Cu: 1.0%-2.5%, Mn≤0.3%, Mg: 1.4%-2.6%, Cr≤0.1%, Zn: 4%-6%, the total amount of other impurities is <0.1%, and the balance is Al.

[0010] The aluminum alloy composite plate according to the embodiment of the present invention has at least the following beneficial effects:

[0011] The present invention forms an aluminum alloy composite plate material through a first aluminum alloy layer and a second aluminum alloy layer with specific component contents. The aluminum alloy composite plate material has aesthetics and high mechanical strength, and the first aluminum alloy layer and the second aluminum alloy layer have high peeling strength.

[0012] Furthermore, in the first aluminum alloy layer of the present invention, Cu can increase the dispersion of the precipitated phase, and form an AlMgSi (Cu) phase together with Mg and Si, and at the same time, part of it plays a role in solid solution strengthening, while solid solution strengthening changes the lattice arrangement of the material, which can reduce the anisotropy caused by the addition of Mn and improve the appearance effect after oxidation. The range of Cu used in the present invention is controlled at 0.4% to 1.1%, so that the alloy has better comprehensive properties. Generally speaking, adding a certain amount of Cu will also lead to an increase in deformation resistance during extrusion, but this point is used in the present invention to reduce the problem of fluidity difference during extrusion caused by the difference in deformation resistance between the first aluminum alloy layer and the second aluminum alloy layer.

[0013] Furthermore, in the first aluminum alloy layer described in the present invention, Mn and Cr are usually used as refining elements, which are difficult to dissolve in the matrix during the extrusion process and are distributed in the cast rod in a fine dispersed state. During the oxidation process, the potential difference with the surrounding matrix causes an increase in corrosion points. Therefore, the present invention limits the mass percentage of Mn and Cr elements to less than 0.1%.

[0014] Furthermore, in the first aluminum alloy layer described in the present invention, Fe is an inevitable harmful impurity in the alloy, often in the form of coarse compounds, which are broken and elongated during extrusion deformation, arranged linearly along the deformation direction, and distributed inside the grains and on the grain boundaries, which will reduce the appearance effect after oxidation. Therefore, the present invention limits the mass percentage of Fe element to less than 0.1%.

[0015] Furthermore, in the first aluminum alloy layer of the present invention, Zn has a relatively high binding energy with the quenching vacancies. After quenching, Zn can combine with the vacancies and serve as the nucleation point of the Mg-Si atomic clusters to accelerate the aging response of the alloy, which is convenient for the aging process with the second aluminum alloy layer during the aging process. However, excessive Zn addition will cause the material matrix to be not corrosion-resistant and affect the oxidation appearance effect, so the range used in the present invention is controlled within 0.1%-0.25%.

[0016] Furthermore, in the second aluminum alloy layer described in the present invention, Mg and Zn are used as main strengthening elements to form MgZn2 and Al2Mg2Zn3 phases, which have great solubility in aluminum and change dramatically with the rise and fall of temperature. MgZn2 has a strong aging response effect, which will lead to an increase in the difference between the aging precipitation efficiency and the first aluminum alloy layer during aging heat treatment, and the increase in Mg and Zn content, strength and hardness. Therefore, the present invention comprehensively considers product performance and aging heat treatment process, and controls the addition amount of Mg and Zn within the range defined by the present invention.

[0017] According to a preferred embodiment of the present invention, in the first aluminum alloy layer, the mass ratio of Mg to Si is (0.6-1.55): 1. Thus, sufficient Mg2Si precipitation strengthening phase is formed, and on the other hand, the interface bonding ability can be provided, thereby improving the peel strength.

[0018] According to a preferred embodiment of the present invention, in the second aluminum alloy layer, the Cu content is 1.2% to 1.5%, thereby preventing the difference in high temperature fluidity between the first aluminum alloy layer and the second aluminum alloy layer from causing poor interface bonding ability.

[0019] According to a preferred embodiment of the present invention, in the second aluminum alloy layer, the mass ratio of Zn to Mg is ≥ 2.2, and the mass percentage of Cu is greater than the mass percentage of Mg, thereby forming a CuMgAl2 phase, which can improve the strength of the alloy.

[0020] According to a second aspect of the present invention, there is provided a method for preparing the aluminum alloy composite plate material according to the first aspect of the present invention, comprising the following steps:

[0021] S1. preparing each component of the first aluminum alloy layer into an ingot A; preparing each component of the second aluminum alloy layer into an ingot B;

[0022] S2, cutting the ingot A into semicircle A; cutting the ingot B into semicircle B; combining the semicircle A and the semicircle B and heating them to obtain an aluminum rod;

[0023] S3, placing the aluminum rod in an extrusion die for extrusion; and then sequentially performing online quenching, stretching and artificial aging treatment to obtain the aluminum rod.

[0024] The method for preparing the aluminum alloy composite plate according to the embodiment of the present invention has at least the following beneficial effects:

[0025] The present invention prepares an aluminum alloy composite plate by subjecting a first aluminum alloy layer and a second aluminum alloy layer to ingot casting, extrusion, online quenching, stretching and artificial aging treatment. The aluminum alloy composite plate prepared by the method has the characteristics of aesthetics, high mechanical strength and peeling strength.

[0026] According to a preferred embodiment of the present invention, in step S2, the semicircle A is chamfered or convex, and the semicircle B is chamfered or convex, thereby ensuring that the semicircle A and the semicircle B are not misaligned during the splicing process, and reducing the interface deformation problem caused by the difference in fluidity between the two materials.

[0027] According to a preferred embodiment of the present invention, the guide groove of the extrusion die is in an inverted cone shape, and the depth of the guide groove is ≥30 mm. Thus, the semicircle A and the semicircle B can be fully welded in the die during the extrusion process, thereby improving the peeling strength.

[0028] According to a preferred embodiment of the present invention, in step S3, the extrusion conditions include at least one of the following:

[0029] i. Extrusion temperature is 500-540℃;

[0030] ii. Extrusion speed is 1.0~6.0mm / s;

[0031] iii. The extrusion coefficient λ is 10 to 80.

[0032] According to a preferred embodiment of the present invention, the online quenching conditions include at least one of the following:

[0033] i. The temperature before quenching is 520-540°C;

[0034] ii. Quenching cooling rate ≥ 30℃ / s;

[0035] iii. The temperature after quenching is ≤80℃.

[0036] According to a preferred embodiment of the present invention, the stretching amount is 0.5% to 1.5%. Thus, the stretching straightens the material and removes the residual stress of the material.

[0037] According to a preferred embodiment of the present invention, the steps of artificial aging treatment are as follows:

[0038] Keep at 120℃ for 16 to 20 hours; then increase the temperature to 190℃ and keep for 1 to 3 hours.

[0039] In this way, the second aluminum alloy layer can be guaranteed to be close to the peak performance, and the first aluminum alloy layer can be guaranteed to produce aging effect quickly. At the same time, the performance of the second aluminum alloy layer will not be significantly reduced due to high-temperature aging.

[0040] According to a preferred embodiment of the present invention, in step S2, the heating temperature is 500-540°C.

[0041] According to a preferred embodiment of the present invention, in step S2, the heating time is 2 to 6 hours.

[0042] The third aspect of the present invention provides an application of the aluminum alloy composite plate in the preparation of 3C products.

[0043] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0045] Figure 1 is a schematic diagram of the preparation process of Example 1 of the present invention;

[0046] Figure 2 1 is a processing shape diagram of semicircle A and semicircle B in embodiment 1 of the present invention;

[0047] Figure 3 1 is a top view and a cross-sectional view of the extrusion die of Example 1 of the present invention;

[0048] Figure 4 is a bonding interface diagram of the aluminum alloy composite plate of Example 1 of the present invention and Comparative Example 1;

[0049] Figure 5 This is a cross-sectional metallographic diagram of the aluminum alloy composite plate material according to Example 1 of the present invention.

[0050] Figure 6 This is a bonding interface diagram of the aluminum alloy composite plate material according to Example 1 of the present invention.

[0051] Figure 7 This is a physical picture of the bending of the aluminum alloy composite plate material according to Example 1 of the present invention.

[0052] Figure 8 It is a peeling force test diagram of the aluminum alloy composite plate materials of Examples 1 to 3 of the present invention.

[0053] Fig. 9 This is a bonding interface diagram of the aluminum alloy composite plate of Comparative Example 5 of the present invention.

[0054] Fig.10 It is the appearance oxidation diagram of the aluminum alloy composite plate material of comparative example 6 and embodiment 1 of the present invention.

[0055] Fig.11 Bonding interface diagram of the aluminum alloy composite plate of Comparative Example 6 of the present invention. DETAILED DESCRIPTION

[0056] The following are specific embodiments of the present invention, and the technical solutions of the present invention are further described in conjunction with the embodiments, but the present invention is not limited to these embodiments.

[0057] Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0058] Example 1

[0059] This example provides an aluminum alloy composite plate, the dosage of each component of which is shown in Table 1, and the flow diagram is as follows Figure 1 As shown, the preparation method is as follows:

[0060] S1. Prepare each component of the first aluminum alloy layer into an ingot A; prepare each component of the second aluminum alloy layer into an ingot B; the preparation steps are as follows (the preparation steps of ingot A and ingot B are the same):

[0061] (1) Raw material preparation: Calculate the weight of raw materials required for the composition ratio in Table 1 by chemical composition calculation and preparation;

[0062] (2) Charging the furnace: charging the aluminum ingots from the above raw materials into the smelting furnace (heat storage type energy-saving furnace);

[0063] (3) Heating and melting: The temperature in the furnace is controlled at 750-780°C to completely melt the aluminum ingot into aluminum melt I;

[0064] (4) Alloying: adding other master alloys to the aluminum melt I, stirring to melt it, and performing preliminary alloying on the melt to obtain aluminum melt II;

[0065] (5) Refining: adding a refining agent to the aluminum melt II obtained in step (4) in an amount of 1 kg / ton of aluminum melt II, the refining temperature is 730-750° C., and the refining time is 40 minutes. During the refining process, the obtained aluminum melt is subjected to chemical composition analysis. If the alloy composition is not within the range described in step (1), the alloy composition is controlled within the range described in step (1) by fine-tuning the composition. During the refining, high-purity argon gas is introduced into the aluminum melt through the air-permeable bricks at the bottom of the furnace for stirring and exhausting, and then the slag is skimmed to obtain aluminum melt III, wherein the argon pressure is controlled at 0.05-0.1 MPa and the flow rate is controlled at 10 L / min.

[0066] (6) Alloy composition analysis: alloy element analysis is performed on the melt III obtained after refining in step (5). If the alloy composition is not within the range described in step (1), the alloy composition is finely adjusted to control the alloy composition within the range described in step (1);

[0067] (7) Standing treatment: The aluminum melt III is allowed to stand for 40 minutes to obtain aluminum melt IV;

[0068] (8) Online degassing: Degassing equipment is used to remove hydrogen and control the IV hydrogen content of the aluminum melt to below 0.12 ml / 100 g.Al aluminum;

[0069] (9) Online filtration: A two-stage filtration system is used for purification. The first aluminum alloy layer adopts an RD-grade foam ceramic tubular filtration device, and the second aluminum alloy layer adopts an 80-mesh + 80-mesh foam ceramic plate filtration device;

[0070] (10) Casting: A semi-continuous water-cooled casting method is used, and the casting temperature is controlled at 680-710° C. to obtain an aluminum alloy round ingot by casting;

[0071] (11) Homogenization treatment: The obtained alloy round ingot is fully homogenized in a homogenization heat treatment furnace to eliminate dendrite segregation.

[0072] S2, ingot A is cut into semicircle A with a length of 350mm; semicircle A is convexly set; ingot B is cut into semicircle B with a length of 350mm; semicircle B is chamfered (such as Figure 2 As shown, the green part is semicircle B, and the yellow part is semicircle A); semicircle A and semicircle B are combined and placed in an aluminum rod heating furnace for heating (temperature is 530° C.; 5 hours) to obtain an aluminum rod;

[0073] S3, place the aluminum rod in the extrusion die (the top view and cross-sectional view of the extrusion die are as shown in Figure 3 As shown, the guide groove is in the shape of an inverted cone structure; the depth of the guide groove is 50 mm) and extrusion is performed (the extrusion machine temperature is 520°C; the extrusion speed (main cylinder forward speed) is 2.0 mm / s, the sample is a 30*5 mm plate, and the extrusion ratio (extrusion coefficient λ) is 45); then online quenching (entering the water-cooled quenching zone within 15 seconds after extrusion from the die, the temperature before entering the quenching zone is 520-540°C, the water temperature is 40°C, the quenching cooling rate is ≥30°C / s, and the temperature after quenching is ≤80°C), stretching (stretching amount is 1.0-1.4%) and artificial aging treatment (keeping at 120°C for 18 hours; then quickly heating to 190°C and keeping for 2 hours) is performed in sequence.

[0074] Embodiment 2-3

[0075] This example provides an aluminum alloy composite plate, the contents of each component of which are shown in Table 1, and the preparation method is the same as that of Example 1.

[0076] Example 4

[0077] This example provides an aluminum alloy composite plate. The diversion depth of the mold is 30 mm, and the component content and preparation method are the same as those in Example 1.

[0078] Comparative Example 1

[0079] This example provides an aluminum alloy composite plate, the component content and preparation method are the same as those in Example 1, the difference being that in step S2, semicircle A has no protrusions and semicircle B has no chamfer design.

[0080] Comparative Example 2

[0081] This example provides an aluminum alloy composite plate, the component content and preparation method are the same as those in Example 1, the difference being that the extrusion die does not have an inverted cone guide design.

[0082] Comparative Example 3

[0083] This example provides an aluminum alloy composite plate, the component content and preparation method are the same as those in Example 1, except that the artificial aging treatment is a single-stage 150° C. insulation for 24 hours.

[0084] Comparative Example 4

[0085] This example provides an aluminum alloy composite plate, the component content and preparation method of which are the same as those of Example 1, except that the first aluminum alloy layer does not contain Zn.

[0086] Comparative Example 5

[0087] This example provides an aluminum alloy composite plate, the component contents of which are shown in Table 1. The preparation method is the same as that of Example 1, except that the heating temperature is 485°C.

[0088] Comparative Example 6

[0089] This example provides an aluminum alloy composite plate, the component contents of which are shown in Table 1. The preparation method is the same as that of Example 1, except that the heating temperature is 485° C., and the artificial aging process is 120° C. for 36 hours.

[0090] Table 1

[0091]

[0092] Performance Testing

[0093] The aluminum bars prepared in Example 1 and Comparative Example 1 were subjected to a bonding interface test, and the results are as follows: Figure 4 As shown, from Figure 4 It can be found that the bonding interface of comparative example 1 is deformed, which affects the use, while the bonding interface of embodiment 1 is a straight line without deformation.

[0094] The aluminum alloy composite plates of Examples 1 to 3 of the present invention and Comparative Examples 2 to 6 were tested as follows, and the results are shown in Table 2:

[0095] Tensile strength and yield strength: refer to GB / T 228.1-2021 for tensile test; specimen specifications are in accordance with GB / T16865-2023.

[0096] Vickers hardness: refer to the test method of GB / T 4340.1-2024.

[0097] Peel strength: Refer to the test method of GB / T 7122-1996, requirement>200N / 10mm.

[0098] Table 2

[0099]

[0100] The cross section of the aluminum alloy composite plate prepared in Example 1 of the present invention was corroded with sodium hydroxide solution and subjected to metallographic analysis. The results are as follows: Figure 5 As shown, the two materials are separated by a relatively straight interface in the middle, and extrusion recrystallization occurs separately without overburning, indicating that the extrusion process settings are relatively reasonable.

[0101] The bonding interface of the aluminum alloy composite plate prepared in Example 1 of the present invention was mechanically polished and photographed. The results are as follows: Figure 6 As shown, it can be seen that metallurgical welding occurs at the interface of the two materials, and there are no pores or large particle inclusions at the interface;

[0102] The aluminum alloy composite plate prepared in Example 1 of the present invention was bent 150°, and the result is as follows: Figure 7 As shown in the figure, due to the different deformation degrees of the metals on both sides of the middle bonding interface, the bonding interface position is shown after bending, but no bending cracking problem occurs;

[0103] The aluminum alloy composite plates prepared in Examples 1 to 3 of the present invention were subjected to peeling force tests, and the results are as follows: Figure 8 As shown, the plateau force values ​​of the test curve of 10mm wide samples are all greater than 300N.

[0104] Comparison of Comparative Example 2 with Example 1 shows that since the mold design does not have an inverted cone-shaped flow guide design, the bonding of the two materials is greatly affected, and the peeling force is reduced by about 70%.

[0105] Comparative Example 3 is compared with Example 1. A single-stage medium-temperature long-term aging scheme is adopted. The aging results show that one side of the first aluminum alloy layer is under-aged (tensile strength is close to the peak value, and yield only reaches 90% of the peak value), and one side of the second aluminum alloy layer is over-aged, with a performance loss of about 18%.

[0106] Compared with Example 1, in Comparative Example 4, no Zn element is added, and the peeling force of the composite board decreases by about 20%.

[0107] Comparative Example 5 is compared with Example 1, and the results are as follows Fig. 9 ; The difference in high-temperature fluidity of the materials is too large, resulting in serious deformation of the bonding interface at the edge of the extruded product.

[0108] Compared with Example 1, Comparative Example 6 increases the alloy composition on the second aluminum alloy layer side, and the heat treatment process is biased towards the second aluminum alloy layer side. This ultimately results in insufficient solid solution and aging effect on the first aluminum alloy layer side, excessive performance degradation, and poor oxidation appearance (such as Fig.10 , Fig.10 The upper middle part is the oxidized appearance of Example 1, and the lower part is the oxidized appearance of Comparative Example 6); and the interface of the extruded product is deformed due to the fluidity problem, such as Fig.11 , the second aluminum alloy layer at the edge is accumulated toward the first aluminum alloy layer.

[0109] The above is a detailed description of the embodiments of the present invention, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. An aluminum alloy composite plate, characterized in that: The aluminum alloy composite plate comprises a first aluminum alloy layer and a second aluminum alloy layer connected in sequence; In terms of mass percentage, the components of the first aluminum alloy layer include Si: 0.4% to 1.2%, Fe≤0.1%, Cu: 0.4% to 1.1%, Mn≤0.1%, Mg: 0.7% to 1.2%, Cr≤0.1%, Zn: 0.1 to 0.25%, the total amount of other impurities is <0.1%, and the balance is Al; In terms of mass percentage, the components of the second aluminum alloy layer include Si≤0.2%, Fe≤0.4%, Cu: 1.0%-2.5%, Mn≤0.3%, Mg: 1.4%-2.6%, Cr≤0.1%, Zn: 4%-6%, the total amount of other impurities is <0.1%, and the balance is Al.

2. The aluminum alloy composite plate according to claim 1, characterized in that: In the first aluminum alloy layer, the mass ratio of Mg to Si is (0.6-1.55):

1.

3. The aluminum alloy composite plate according to claim 1, characterized in that: In the second aluminum alloy layer, the Cu content is 1.2% to 1.5%.

4. A method for preparing the aluminum alloy composite plate according to any one of claims 1 to 3, characterized in that: The steps include: S1. preparing each component of the first aluminum alloy layer into an ingot A; preparing each component of the second aluminum alloy layer into an ingot B; S2, cutting the ingot A into semicircle A; cutting the ingot B into semicircle B; combining the semicircle A and the semicircle B and heating them to obtain an aluminum rod; S3, placing the aluminum rod in an extrusion die for extrusion; Then carry out online quenching, stretching and artificial aging treatment in sequence to obtain the product.

5. The preparation method according to claim 4, characterized in that: In step S2, the semicircle A is chamfered or convexly provided; the semicircle B is chamfered or convexly provided.

6. The preparation method according to claim 4, characterized in that: The guide groove of the extrusion die is in the shape of an inverted cone structure; the depth of the guide groove is ≥30mm.

7. The preparation method according to claim 4, characterized in that: In step S3, the extrusion conditions include at least one of: i. Extrusion temperature is 500-540℃; ii. Extrusion speed is 1.0~6.0mm / s; iii. The extrusion coefficient λ is 10 to 80.

8. The preparation method according to claim 4, characterized in that: The online quenching conditions include at least one of: i. The temperature before quenching is 520-540°C; ii. Quenching cooling rate ≥ 30℃ / s; iii. The temperature after quenching is ≤80℃.

9. The preparation method according to claim 4, characterized in that: The steps of the artificial aging treatment are as follows: keeping the temperature at 120° C. for 16 to 20 hours; and then heating to 190° C. and keeping the temperature for 1 to 3 hours.

10. Use of the aluminum alloy composite plate material according to any one of claims 1 to 3 in the preparation of 3C products.

Images