A method for preparing a SiC reinforced aluminum alloy ultra-thin plate

Abstract

The application discloses a preparation method of a SiC reinforced aluminum alloy ultra-thin plate. The preparation method comprises the treatment steps of hot extrusion, hot rolling, cold rolling and heat treatment. The plate rolling and heat treatment steps are specifically optimized, the problems of uneven structure and thermal stress concentration of the high-content SiC reinforced aluminum alloy ultra-thin plate in the preparation process are effectively solved, the high-performance and high-uniformity ultra-thin plate preparation is realized, and the use demand of the aluminum matrix composite under the miniaturization and integration development trend can be met.

Description

Technical Field

[0001] This invention relates to the field of aluminum-based composite materials technology, and specifically to a method for preparing SiC-reinforced aluminum alloy ultrathin plates. Background Technology

[0002] Aluminum-based composites have become ideal materials for lightweight design in aerospace, electronic packaging, and precision instruments due to their excellent specific strength, specific stiffness, and good dimensional stability. Among them, silicon carbide (SiC) reinforced aluminum-based composites have attracted much attention due to their high hardness, high modulus, and good wear resistance. As modern equipment develops towards miniaturization, integration, and high reliability, thinner and more precise components made of such materials are required, and the demand for ultra-thin plates with a thickness of less than 1 mm is becoming increasingly urgent.

[0003] However, in the preparation of SiC-reinforced aluminum matrix composite sheets, when the SiC reinforcing phase content is high, the high-hardness SiC particles are prone to agglomeration in the aluminum matrix, forming local stress concentration sources. This leads to inhomogeneity in the internal structure of the material, with defects such as unbonded areas and micropores. Under tensile stress, stress concentration easily occurs, reducing the load-bearing and load-transferring capacity. As the external force increases, crack initiation occurs, resulting in a decrease in tensile strength and yield strength. This microstructural inhomogeneity is further amplified when the sheet is rolled to ultra-thin specifications, manifesting as significant fluctuations in the mechanical properties of different batches or even different regions of the same sheet, severely affecting product reliability and yield.

[0004] While there is extensive research on aluminum alloy rolling processes in the existing technology, there is still a lack of effective solutions for ensuring uniform performance of high-SiC reinforced materials in the preparation of ultra-thin plates. To meet performance requirements, aluminum-based composite materials often require heat treatment to improve their properties. Traditional heat treatment involves heating the plate at high temperatures and holding it at a constant temperature for a certain time, followed by rapid cooling (quenching) to obtain a supersaturated solid solution. However, for ultra-thin plates, traditional heat treatment methods are prone to severe deformation due to internal stress, affecting the product's stability. Chinese patent application CN117753823A discloses a method for continuous heat treatment and leveling of large-size ultra-thin aluminum-based composite materials. This method employs a continuous heat treatment process consisting of hot-plate and cold-plate pressing. The heat treatment is performed by controlling the holding pressure, holding temperature, and holding time. The plate is then transported by conveyor belt and immediately leveled using a high-precision CNC leveling machine. The flatness of the plate is controlled by adjusting the roller spacing. Finally, stress relief and pitting are applied to address the problem of warping and twisting of the workpiece due to internal stress during processing. Although this method can solve the stress deformation problem in the processing of aluminum-based composite materials, the continuous heat treatment during implementation requires extremely high control over the holding pressure, temperature and time. Slight deviations can easily lead to uneven performance or deformation of the sheet material. Immediate leveling relies on high-precision equipment, and improper adjustment of the roller spacing may affect the flatness effect. Stress relief by pitting can damage the surface quality. The overall process is complex, requires large equipment investment, has high technical requirements for operators, and is difficult to scale up.

[0005] Therefore, the present invention aims to develop a method for preparing ultrathin plates of SiC-reinforced aluminum matrix composites with high uniformity, in order to meet the current demand for aluminum matrix composites under the trend of miniaturization and integration. Summary of the Invention

[0006] To overcome the shortcomings of the existing technology, the present invention aims to provide a method for preparing SiC reinforced aluminum alloy ultrathin plates.

[0007] This invention is achieved through the following technical solution:

[0008] In a first aspect, the present invention provides a method for preparing a SiC-reinforced aluminum alloy ultrathin plate, comprising the following steps: S1. Hot extrusion: Hot extrusion is carried out by holding aluminum alloy ingots with SiC volume percentage of 10%-30% at 480-520℃ for 5-20h. S2. Hot rolling: The extruded billet is held at 450℃-500℃ for 10-60 minutes, and then hot rolled in multiple passes at this temperature. The reduction rate per pass is 10%-20%, and the total cumulative deformation is 40-60%; to obtain aluminum alloy sheet with a thickness of 1-1.5mm. S3. Cold rolling: The hot-rolled sheet is subjected to multiple cold rolling passes at 20-30℃, with a single pass reduction rate of 3%-12% and a cumulative total deformation of 40-90%, to obtain an aluminum alloy sheet with a thickness of 0.1-0.6mm; S4. Heat treatment: The cold-rolled aluminum alloy sheet is held at 400-450℃ for 1-4 hours and then cooled in the furnace to 20-30℃; then it is held at 480-500℃ for 10-20 minutes for solution treatment, and then heated to 520-550℃ for 30-50 minutes for solution treatment; then it is quenched; finally, it is aged at 140-170℃ for 2-6 hours and air-cooled to below 30℃ to prepare SiC reinforced aluminum alloy ultrathin sheet.

[0009] Furthermore, the aluminum alloy ingot is selected from the 6XXX series aluminum alloy.

[0010] Furthermore, in step S2, the heat preservation time before hot rolling is preferably 30-50 minutes. This invention performs a heat preservation treatment for a certain period before hot rolling, which is beneficial for achieving sufficient diffusion of SiC particles and stress homogenization, thereby improving the consistency of the final sheet material's performance.

[0011] Furthermore, in step S2, after heat preservation, 8-15 passes of hot rolling are performed.

[0012] Furthermore, in step S2, the interval between hot rolling passes is 10-20 minutes.

[0013] Furthermore, in step S3, after hot rolling, 15-40 passes of cold rolling are performed.

[0014] Furthermore, in step S3, the interval between cold rolling passes is 1-5 minutes. Controlling the interval time allows the material to recover between passes, preventing cracking caused by heat accumulation during deformation and excessively rapid work hardening, which would affect the uniformity of the sheet material's properties.

[0015] Further, in step S4, the cold-rolled aluminum alloy sheet is held at 420-440℃ for 2-3 hours. In the heat treatment step, treating the material at a specific temperature for a certain time provides a strong diffusion driving force for atoms, promoting the homogenization of micro-composition segregation generated during the initial preparation or rolling process, and effectively eliminating the micro-internal stress accumulated in the interface region due to the difference in thermal expansion coefficients between SiC particles and the aluminum matrix. This is beneficial for obtaining uniform mechanical properties in subsequent solution treatment.

[0016] The heat treatment method of the present invention adopts a segmented solution treatment. First, pre-dissolve at a lower temperature to promote the interfacial reaction between the reinforcing phase and the aluminum matrix, generating a fine, coherent intermetallic compound transition layer with the matrix, thereby optimizing the interfacial structure, relieving thermal mismatch stress and enhancing the interfacial bonding strength. Then, further high-temperature solution treatment ensures that the alloying elements are fully dissolved, while avoiding grain coarsening caused by a single high temperature, thus balancing the uniformity of reinforcing phase precipitation and interfacial strength.

[0017] Furthermore, in step S4, the aging treatment temperature is 150-160℃, and the aging treatment time is 3-5 hours. Aging treatment is beneficial for the uniform nucleation of the strengthening phase, improving mechanical properties and long-term stability. Excessive aging treatment time may lead to over-coarsening of the strengthening phase, which in turn may reduce the material's hardness and strength.

[0018] Further, in step S4, the quenching process involves rapidly transferring the solution-treated plate to a quenching medium for quenching, with the transfer time controlled within 1-20 seconds. Preferably, the quenching medium is water, and the water temperature is 10-30℃.

[0019] Secondly, the present invention provides a SiC-reinforced aluminum alloy ultrathin plate, which is prepared by the preparation method described in the present invention.

[0020] The present invention has the following beneficial effects: The preparation method of this invention has specifically optimized the rolling and heat treatment steps of the plate, effectively solving the problems of uneven microstructure and thermal stress concentration in the preparation process of high-SiC reinforced aluminum alloy ultrathin plates. It realizes the preparation of high-performance and highly uniform ultrathin plates, which can meet the needs of aluminum-based composite materials under the trend of miniaturization and integration. Attached Figure Description

[0021] Figure 1 Box plots showing the hardness performance test results of Examples 1-2 and Comparative Examples 2-8; Figure 2 Box plots showing the tensile strength test results of Examples 1-2 and Comparative Examples 2-8; Figure 3 Box plots showing the yield strength test results of Examples 1-2 and Comparative Examples 2-8; Figure 4 Box plots show the elongation performance test results of Examples 1-2 and Comparative Examples 2-8. Detailed Implementation

[0022] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0023] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0024] Unless otherwise specified, room temperature or normal temperature in the embodiments of the present invention refers to 25±1℃.

[0025] The materials used in the embodiments and comparative examples of the present invention are described below, but are not limited to these materials: Example 1 This embodiment provides a method for preparing SiC-reinforced aluminum alloy ultrathin plates, the steps of which are as follows: S1. Hot extrusion: 6092Al aluminum alloy ingots with SiC volume percentage of 21% are hot extruded at 500℃ for 8 hours. The extrusion is constant flow extrusion with a speed of 1.2m / min, an extrusion ratio of 56, and an extrusion press tonnage of 1100T. S2. Hot rolling: The extruded billet is held at 460℃ for 50 minutes, and then hot rolled in 9 passes at this temperature. The reduction rate per pass is about 15%, and the interval between passes is 12 minutes to obtain an aluminum alloy sheet with a thickness of 1.0 mm. S3. Cold rolling: The hot-rolled sheet is cold-rolled for 15 passes at room temperature, with a single pass reduction of about 6% and a pass interval of 2 minutes, to obtain an aluminum alloy sheet with a thickness of 0.4 mm. S4. Heat treatment: The cold-rolled aluminum alloy sheet is placed at 420℃ for 2 hours and then cooled to room temperature in the furnace; then it is heated to 490℃ for 15 minutes and then heated to 525℃ for 40 minutes; it is then quickly transferred to water at 25℃ for quenching, with the transfer time controlled within 5 seconds; finally, it is aged at 160℃ for 4 hours and then air-cooled to room temperature to obtain SiC reinforced aluminum alloy ultrathin sheet.

[0026] Example 2 This embodiment provides a method for preparing SiC-reinforced aluminum alloy ultrathin plates, the steps of which are as follows: S1. Hot extrusion: 6061Al aluminum alloy ingots with SiC volume percentage of 30% are hot extruded at 500℃ for 8 hours. The extrusion is constant flow extrusion with a speed of 1.2m / min, an extrusion ratio of 56, and an extrusion press tonnage of 1100T. S2. Hot rolling: The extruded billet is held at 500℃ for 30 minutes, and then hot rolled in 12 passes at the same temperature. The reduction rate per pass is about 12%, and the interval between passes is 14 minutes, to obtain an aluminum alloy sheet with a thickness of 1.0 mm. S3. Cold rolling: The heat-treated sheet is cold rolled for 40 passes at room temperature, with a single pass reduction of about 5% and a pass interval of 5 minutes, to obtain an ultra-thin aluminum alloy sheet with a thickness of 0.15mm.

[0027] S4. Heat treatment: The hot-rolled aluminum alloy sheet is treated at 450℃ for 2 hours and then cooled to room temperature in the furnace; then it is heated to 490℃ for 15 minutes and then heated to 540℃ for 30 minutes; it is then quickly transferred to water at 25℃ for quenching, and the transfer time is controlled within 5 seconds; finally, it is aged at 140℃ for 5 hours and then air-cooled to room temperature to prepare SiC reinforced aluminum alloy ultrathin sheet.

[0028] Comparative Example 1 The difference between Comparative Example 1 and Example 1 lies in the S2 hot rolling step: the extruded billet is directly subjected to multiple hot rolling passes at 460°C, which makes it impossible to form and thus impossible to prepare SiC reinforced aluminum alloy ultrathin plates.

[0029] Comparative Example 2 The only difference between Comparative Example 2 and Example 1 is the S4 heat treatment step; the other steps are the same as in Example 1. The S4 heat treatment steps for Comparative Example 2 are as follows: The hot-rolled aluminum alloy sheet is placed at 420℃ and held for 2 hours, then cooled to room temperature in the furnace; then heated to 525℃ and held for 40 minutes for solution treatment; then quickly transferred to water at 25℃ for quenching, with the transfer time controlled within 5 seconds; finally, aged at 160℃ for 4 hours and air-cooled to room temperature.

[0030] Comparative Example 3 The only difference between Comparative Example 3 and Example 1 is the S4 heat treatment step; the other steps are the same as in Example 1. The S4 heat treatment steps of Comparative Example 3 are as follows: The cold-rolled aluminum alloy sheet is placed at 350℃ for 2 hours and then cooled to room temperature in the furnace; then it is heated to 490℃ for 15 minutes and then heated to 525℃ for 40 minutes; it is quickly transferred to water at 25℃ for quenching, and the transfer time is controlled within 5 seconds; finally, it is aged at 160℃ for 4 hours and then air-cooled to room temperature.

[0031] Comparative Example 4 The only difference between Comparative Example 4 and Example 1 is the S4 heat treatment step; the other steps are the same as in Example 1. The S4 heat treatment steps for Comparative Example 4 are as follows: The cold-rolled aluminum alloy sheet is placed at 500℃ for 2 hours and then cooled to room temperature in the furnace; then it is heated to 490℃ for 15 minutes and then heated to 525℃ for 40 minutes; it is quickly transferred to water at 25℃ for quenching, and the transfer time is controlled within 5 seconds; finally, it is aged at 160℃ for 4 hours and then air-cooled to room temperature.

[0032] Comparative Example 5 The only difference between Comparative Example 5 and Example 1 is the S4 heat treatment step; the other steps are the same as in Example 1. The S4 heat treatment steps for Comparative Example 5 are as follows: The cold-rolled aluminum alloy sheet is kept at 490℃ for 15 minutes for solution treatment, and then heated to 525℃ for 40 minutes for solution treatment; it is then quickly transferred to water at 25℃ for quenching, with the transfer time controlled within 5 seconds; finally, it is aged at 160℃ for 4 hours and then air-cooled to room temperature.

[0033] Comparative Example 6 The only difference between Comparative Example 6 and Example 1 is the S4 heat treatment step; the other steps are the same as in Example 1. The S4 heat treatment steps for Comparative Example 6 are as follows: The cold-rolled aluminum alloy sheet is placed at 450℃ for 6 hours and then cooled to room temperature in the furnace; then it is kept at 525℃ for 12 hours for solution treatment, and then quickly transferred to 60℃ water for quenching, with the transfer time controlled within 5 seconds; finally, it is aged at 175℃ for 4 hours and then air-cooled to room temperature.

[0034] Comparative Example 7 The only difference between Comparative Example 8 and Example 1 is that 6092Al aluminum alloy ingots with a SiC volume percentage of 40% are used, and the preparation steps are the same as those in Example 1.

[0035] Comparative Example 8 The only difference between Comparative Example 9 and Example 1 is that 6092Al aluminum alloy ingots with a SiC volume percentage of 5% are used, and the preparation steps are the same as those in Example 1.

[0036] Relevant performance tests: 1. Hardness Testing: A micro Vickers hardness tester was used, following ASTM E384 standard. Test conditions were: test force 500 gf, holding time 15 s, observation and measurement of the diagonal length of the indentation using a 40x optical microscope, followed by calculation of the Vickers hardness value (HV) according to the formula. At least 5 points were tested on each sample, and the average value was taken as the final hardness result.

[0037] 2. Tensile property testing: Tests were conducted according to standard GB / T 228-2002. Standard tensile specimens were punched from the sheet metal, with a gauge length of 25 mm. Before the tensile test, 400# and 1000# sandpaper were used to remove punching marks from the specimen surface to avoid the influence of the heat-affected zone on the experimental results. The room temperature tensile test was performed on a universal testing machine with a tensile rate set to 1 mm / min. Specimens were prepared from three randomly selected locations on the same sheet metal, and the results were recorded and calculated (as shown in Table 1). Box plots of the test results were then generated (e.g., ...). Figures 1-4 As shown in the figure, the greater the fluctuation in the test data at the three different locations, the worse the uniformity of the board performance.

[0038] Table 1. Performance test results (average) of the examples and comparative examples.

[0039] As can be seen from the above results, the method of the present invention can prepare SiC reinforced aluminum alloy ultrathin plates with a thickness of ≤0.6mm, which have excellent properties such as hardness, strength and elongation, and can achieve high uniformity of ultrathin plates.

[0040] Comparative Example 1 was not heat-insulated before hot rolling, and the material could not be formed.

[0041] Comparative Examples 2-6, where the heat treatment step did not employ the method of this invention, resulted in a decrease in the performance of the ultrathin plates prepared, and... Figures 1-4 It can be seen that the performance of the board fluctuates greatly in different locations, and the uniformity is poor.

[0042] Comparative Example 7 uses ingots with excessively high SiC content. Although the hardness and tensile strength are significantly improved, the elongation is low and the performance of different parts of the plate fluctuates greatly. Excessively high SiC content can easily lead to brittleness and inhomogeneity.

[0043] Comparative Example 8 used ingots with too low SiC content. Although the elongation was high, the strength and hardness were significantly insufficient, failing to meet the usage requirements.

[0044] The above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a SiC-reinforced aluminum alloy ultrathin plate, characterized in that, Includes the following steps: S1. Hot extrusion: Hot extrusion is carried out by holding aluminum alloy ingots with SiC volume percentage of 10%-30% at 480-520℃ for 5-20h. S2. Hot rolling: The extruded billet is held at 450℃-500℃ for 10-60 minutes, and then hot rolled in multiple passes at this temperature. The reduction rate per pass is 10%-20%, and the total cumulative deformation is 40-60%; to obtain aluminum alloy sheet with a thickness of 1-1.5mm. S3. Cold rolling: The hot-rolled sheet is subjected to multiple cold rolling passes at 20-30℃, with a single pass reduction rate of 3%-12% and a cumulative total deformation of 40-90%, to obtain an aluminum alloy sheet with a thickness of 0.1-0.6mm; S4. Heat treatment: The cold-rolled aluminum alloy sheet is held at 400-450℃ for 1-4 hours and then cooled in the furnace to 20-30℃; then it is held at 480-500℃ for 10-20 minutes for solution treatment, and then heated to 520-550℃ for 30-50 minutes for solution treatment; then it is quenched; finally, it is aged at 140-170℃ for 2-6 hours and air-cooled to below 30℃ to prepare SiC reinforced aluminum alloy ultrathin sheet.

2. The preparation method according to claim 1, characterized in that, The aluminum alloy ingot is selected from the 6XXX series aluminum alloy.

3. The preparation method according to claim 1, characterized in that, In step S2, the heat preservation time before hot rolling is 30-50 minutes.

4. The preparation method according to claim 1, characterized in that, In step S2, the interval between hot rolling passes is 10-20 minutes.

5. The preparation method according to claim 1, characterized in that, In step S3, the interval between cold rolling passes is 1-5 minutes.

6. The preparation method according to claim 1, characterized in that, In step S4, the cold-rolled aluminum alloy sheet is kept at 420-440℃ for 2-3 hours.

7. The preparation method according to claim 1, characterized in that, In step S4, the aging treatment temperature is 150-160℃, and the aging treatment time is 3-5 hours.

8. The preparation method according to claim 1, characterized in that, In step S4, the quenching process involves rapidly transferring the solution-treated plate to a quenching medium for quenching, with the transfer time controlled between 1 and 20 seconds.

9. The preparation method according to claim 8, characterized in that, The quenching medium is water, and the water temperature is 10-30℃.

10. A SiC-reinforced aluminum alloy ultrathin plate, characterized in that, It is prepared by the preparation method according to any one of claims 1-9.

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