Reversible rolling method of aluminum-based silicon carbide composite material

Abstract

The invention discloses a reversible rolling method of an aluminum-based silicon carbide composite material, and aims to solve the problems of poor stability caused by uneven heating, interface reaction and large fluctuation of rolling temperature, difficulty in synergistic deformation of particles and a matrix and the like in the prior art. The method comprises the steps that before a strip enters a roller of a reversible mill, a medium-frequency electromagnetic induction heating device is adopted for online heating, and selective rapid heating of an aluminum matrix is achieved through the electromagnetic property difference between the aluminum matrix and silicon carbide particles; in the backward pass of the reversible rolling, the strip is subjected to online temperature compensation so as to maintain the temperature of each pass to be consistent; and the heating power, the rolling speed and the rolling force are cooperatively controlled through the central control system in combination with real-time feedback of the thermodetector, so that closed-loop control is formed. According to the method, generation of harmful interface brittle phases is inhibited, the particle breakage rate is reduced, stable continuous reversible rolling is achieved, and the method is particularly suitable for machining of high-performance composite materials with the silicon carbide particle volume fraction of 10%-30%.

Description

Technical Field

[0001] This invention relates to the field of metal matrix composite material processing technology, and more particularly to a plastic forming processing method for hard particle reinforced metal matrix composite materials. Specifically, it is a reversible rolling method for aluminum-based silicon carbide (SiCp / Al) composite strips or coils. Background Technology

[0002] Aluminum-based silicon carbide (SiCp / Al) composites, as a typical hard-particle reinforced metal matrix composite, have shown great application potential in aerospace, automotive, and electronic packaging fields due to their high specific strength, high specific modulus, low coefficient of thermal expansion, and excellent wear resistance. Processing SiCp / Al composites into thin sheets or strips is a key step in realizing their engineering applications. Rolling, as an efficient and continuous sheet metal production method, is considered the ideal choice for forming and processing SiCp / Al composites.

[0003] However, the rolling process of SiCp / Al composite materials still faces several technical challenges that existing technologies cannot effectively address, specifically in the following three aspects: Heating Contradictions: Traditional rolling processes commonly employ offline, integral heating methods such as resistance furnaces and gas furnaces. This method has two inherent drawbacks: First, poor heating uniformity. Because the thermal conductivity of silicon carbide particles is much lower than that of the aluminum matrix, a significant temperature gradient exists between the matrix and particles during prolonged heating, leading to internal stress concentration during rolling and making the silicon carbide particles highly susceptible to breakage. Second, severe interfacial reactions. To achieve sufficient plasticity, traditional heating temperatures typically need to be in the range of 350-480℃, with heating times lasting several hours. Under prolonged high temperatures, harmful interfacial chemical reactions easily occur between the aluminum matrix and silicon carbide particles (e.g., 4Al + 3SiC → Al4C3 + 3Si). The resulting brittle Al4C3 phase severely fractures the matrix, becoming a crack initiation point and drastically reducing the material's mechanical properties and reliability.

[0004] The challenge of rolling stability: SiCp / Al composite materials have high hardness and poor plastic deformation capacity. During multi-pass reversible rolling, the strip temperature fluctuates drastically due to the combined effects of ambient heat dissipation and rolling deformation heat. This temperature fluctuation directly leads to inconsistent deformation resistance of the material in each pass, making the rolling process extremely unstable and prone to defects such as edge cracking and severe thickness unevenness. Especially in reversible rolling, the strip temperature drops significantly as it moves backward, and current technology lacks a suitable online rapid temperature compensation solution. Typically, offline temperature compensation methods such as stopping the machine, unwinding the coil, and reheating are used, resulting in extremely low production efficiency and an inability to guarantee temperature consistency across passes.

[0005] The challenge of coordinated deformation between particles and the matrix: Silicon carbide particles are characterized by high hardness and brittleness, while the aluminum matrix has good plasticity and low strength, resulting in a significant difference in their properties. Under traditional integral heating methods, the softening of the matrix and particles is asynchronous. During rolling, the flow of the softer matrix is ​​hindered by the harder particles, causing the particles to bear excessive shear stress and fracture; or the interfacial bonding strength between the matrix and particles is insufficient, leading to delamination and the formation of voids. Both of these microscopic damages contribute to a decline in the overall macroscopic material properties.

[0006] In summary, existing technologies have failed to fundamentally solve the three core challenges of heating, stability, and coordinated deformation in the rolling process of SiCp / Al composite materials, severely hindering the industrialization of such high-performance composite sheet materials. Therefore, there is an urgent need in this field for a novel rolling technology solution that can systematically address the aforementioned technical bottlenecks, particularly suitable for processing composite materials with a silicon carbide particle volume fraction of 10%–30%. Summary of the Invention

[0007] This invention aims to overcome the shortcomings of the prior art and provide a reversible rolling method for aluminum-based silicon carbide composite materials. This method solves the technical problems existing in traditional rolling technology, such as uneven heating and interfacial reaction, large rolling temperature fluctuations leading to poor stability, and difficulty in the coordinated deformation of particles and matrix. It is applicable to the processing of high-performance composite materials with a silicon carbide particle volume fraction of 10% to 30%.

[0008] To achieve the above objectives, the present invention provides a reversible rolling method for aluminum-based silicon carbide composite materials, characterized by comprising the following steps: S001. A strip of aluminum-based silicon carbide composite material to be rolled is provided, the composite material comprising a conductive aluminum matrix and non-conductive or weakly conductive silicon carbide particles dispersed therein; S002. Before and / or during the rolling process of the strip entering the reversible rolling mill, an online induction heating device is used to induction heat the metal components in the strip; wherein, the medium-frequency electromagnetic induction heating is based on the eddy current effect, and Joule heating is generated only in the conductive aluminum matrix to achieve temperature rise, while the non-conductive SiC particles do not generate eddy currents and rely on thermal conduction with the aluminum matrix to achieve synchronous temperature rise, thereby forming an ideal rolling state of 'softened matrix and rigid particles'; S003. The reversible rolling process includes at least one forward rolling pass and one backward rolling pass. When the strip completes one pass and moves backward to proceed to the next pass, the strip is again subjected to online temperature compensation by the medium-frequency electromagnetic induction heating device to compensate for the temperature drop caused by environmental heat dissipation and rolling deformation, ensuring the consistency of rolling temperature in each pass. The online temperature compensation refers to the compensation of the temperature drop caused by environmental heat dissipation and deformation heat loss during the rolling process by the medium-frequency electromagnetic induction heating device when the strip moves backward, so that the difference between the temperature of the strip after temperature compensation and the rolling temperature of the previous pass is controlled within ±10℃. S004. The central control system receives the real-time temperature of the strip and controls the heating power of the medium-frequency electromagnetic induction heating device, the rolling speed and rolling force of the reversible rolling mill in real time to maintain stable rolling of the strip within the set rolling temperature range; wherein, the strip temperature is detected in real time by an infrared thermometer and fed back to the central control system to form a closed-loop control.

[0009] Furthermore, in step S002, the operating frequency of the medium-frequency electromagnetic induction coil for heating is 1~10kHz.

[0010] Furthermore, in step S002, the heating rate of the medium-frequency electromagnetic induction heating is adjusted according to the thickness of the strip and the rolling speed, and the heating rate is 20~100℃ / s.

[0011] Further, in step S004, the set rolling temperature range is 350℃-480℃, and the rolling temperature refers to the temperature of the strip before it enters the rolls, specifically the temperature measured by an infrared thermometer before the strip enters the rolls.

[0012] Furthermore, in step S004, the central control system and the reversible rolling mill also include a hydraulic automatic thickness control (AGC) system working together to control the thickness tolerance of the finished strip within ±0.02mm by stabilizing the rolling temperature.

[0013] Furthermore, prior to step S001, a pretreatment step is included for the edge of the aluminum-based silicon carbide composite strip, wherein the pretreatment includes diffusion welding edge wrapping using nickel-plated copper strip.

[0014] Furthermore, the volume fraction of silicon carbide particles in the aluminum-based silicon carbide composite material is 10% to 30%.

[0015] Further, in step S003, the reduction rates of each pass in the hot rolling process are set sequentially as 35%, 30%, 25%, 20%, 17%, 15%, and 12%.

[0016] Compared with the prior art, the present invention has the following significant advantages: The invention resolves the heating contradiction by employing "medium-frequency electromagnetic induction selective heating," utilizing the electrical conductivity of the aluminum matrix and the non-electrical nature of SiC particles to achieve instantaneous and rapid heating of the matrix. Heating time is reduced from several hours to just seconds, significantly suppressing the formation of brittle phases such as Al4C3 and protecting interface integrity. Simultaneously, the resulting ideal state of "softened matrix and rigid particles" promotes synergistic deformation, reducing particle breakage. Compared to traditional resistance furnace heating and rolling processes, this invention, based on actual measurements, reduces Al4C3 formation by over 95% and increases particle integrity by over 35%.

[0017] Stable, continuous, and reversible rolling has been achieved: Medium-frequency induction heating is deeply integrated with the reversible rolling mill, and an "automatic heating compensation during backward operation" mechanism is designed. Combined with the collaborative logic of the central control system and standardized reduction rate settings, this ensures constant rolling temperature and deformation for each pass. This not only solves the problem of deformation resistance fluctuations caused by temperature drop but also enables continuous production without downtime. Compared to traditional offline heating processes, production efficiency is increased by 2-3 times, and the finished product thickness accuracy can reach ±0.02mm, far superior to the ±0.05mm of traditional technologies.

[0018] The coordinated deformation behavior of particles and the matrix was optimized: by selectively heating and actively controlling the deformation mechanism, the softened aluminum matrix can flow uniformly to encapsulate and transfer the load to the rigid SiC particles. Combined with a scientific reduction ratio distribution, particle breakage or peeling due to stress concentration is avoided. With the addition of auxiliary measures such as edge pretreatment, persistent problems such as edge cracking are effectively solved, resulting in a 10%-30% improvement in the mechanical properties of the finished material (such as tensile strength and hardness) compared to traditional processes.

[0019] This solution expands the boundaries of technology application: It is the first to realize the continuous reversible rolling of SiCp / Al composite material rolls and provides a feasible industrialization path for the processing of low to medium volume fraction (10%~30%) SiCp / Al composite materials, filling a technological gap in the industry and possessing significant industry value and broad market prospects. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the reversible rolling system for aluminum-based silicon carbide composite materials described in this invention.

[0021] Explanation of markings in the diagram: 1. Uncoiling device; 2. First pinch roll; 3. Medium frequency electromagnetic induction heating device; 4. Reversible rolling mill; 5. Second pinch roll; 6. Coiling device; 7. Central control system; 8. Strip; 9. Infrared thermometer; Infrared thermometer 9 is installed between medium-frequency electromagnetic induction heating device 3 and reversible rolling mill 4. Its temperature detection signal is transmitted to central control system 7 in real time. Central control system 7 outputs control commands to medium-frequency electromagnetic induction heating device 3 and reversible rolling mill 4 according to the temperature signal.

[0022] Figure 2 This is a cross-sectional schematic diagram of the positional relationship between the coil and the strip in the medium-frequency electromagnetic induction heating device of the present invention. The distance between the coil and the strip 8 is 5~10mm. After the medium-frequency current is passed through the coil, an alternating magnetic field is generated. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the invention.

[0024] The following 10 specific embodiments illustrate the process and effects of the present invention in detail. All embodiments use the apparatus described in the above system embodiments, and the reduction rates of each hot rolling pass are set sequentially to 35%, 30%, 25%, 20%, 17%, 15%, and 12%.

[0025] General process flow: Material preparation: Depending on the needs, edge pretreatment may be required. Use aluminum-based silicon carbide composite strip with a silicon carbide particle volume fraction of 10% to 30%.

[0026] Threading: The strip 8 is drawn out from the uncoiling device 1, passes through the first pinch roll 2, the medium frequency electromagnetic induction heating device 3, the reversible mill 4, the second pinch roll 5 in sequence, and finally connects to the coiling device 6.

[0027] Setting parameters: Input rolling instructions into the central control system 7 and set the reduction rate for each pass as 35%, 30%, 25%, 20%, 17%, 15%, and 12%.

[0028] Rolling Start: The system is started, and strip 8 begins operation. Before entering the reversible mill 4, the medium-frequency electromagnetic induction heating device 3 rapidly heats it to the target temperature. The first pass is forward rolling.

[0029] Reverse rolling: After the first pass, the strip moves backward under the drive of the second pinch roll 5 and the winding device 6, and is reheated again by the medium frequency electromagnetic induction heating device 3, and then the second rolling is performed.

[0030] Repeated rolling process: The rolling steps are repeated, and each rolling pass is completed according to the set reduction rate until the final target thickness is reached.

[0031] Rewinding: After rolling is completed, the finished strip is wound into a coil by the winding device 6.

[0032] Example 1: Rolling of low volume fraction (10%) SiCp / Al composite material (without edge wrapping) This embodiment uses SiCp / Al composite strip with a volume fraction of 10% and an average particle size of 5μm, with an initial thickness of 5.0mm, without edge pretreatment (without edge wrapping), to verify the rolling stability of low volume fraction materials under edgeless conditions.

[0033] Parameter selection criteria: The SiC particles in low volume fraction materials are sparsely distributed, which has little impact on the eddy current distribution. A lower frequency (3kHz) can be selected to ensure uniform heating of the matrix. The initial thickness is moderate. With the first pass set at a reduction rate of 35%, the plasticity of the material can be fully utilized, while avoiding excessive stress concentration at the edge when there is no edge wrapping.

[0034] Process Specification Table: Results and Comparison with Traditional Processes: A finished strip with a thickness of 0.85 mm was successfully obtained after 7 passes of continuous reversible rolling. The rolling process was generally stable, the strip surface was smooth, and there were no obvious cracks or peeling. Slight burrs (width ≤ 0.3 mm) were present at the edges due to the lack of edging. Testing showed that the finished product had a tensile strength of 310 MPa, an elongation of 4.8%, and a thickness tolerance controlled within ±0.015 mm. The SiC particle integrity rate was 95.2%, and no Al4C3 brittle phase was detected. Using traditional processes (offline heating in a resistance furnace, heating time 2 hours, no online temperature compensation) to process the same material, the finished product has a tensile strength of only 265 MPa (14.5% lower than in this embodiment), an elongation of 3.9% (18.8% lower than in this embodiment), a thickness tolerance of ±0.042 mm (accuracy only 35.7% of that in this embodiment), a SiC particle integrity rate of 88.6% (6.9 percentage points lower than in this embodiment), and a trace amount of Al4C3 brittle phase was detected, with burr width at the edges reaching 0.6~0.9 mm.

[0035] Example of the invention: This example demonstrates that even without edge wrapping, the medium-frequency electromagnetic induction online heating + reversible rolling method of the present invention still has good adaptability to low volume fraction (10%) SiCp / Al composite materials and can achieve stable rolling. Compared with the traditional process, it can significantly improve the mechanical properties, dimensional accuracy and SiC particle integrity of the finished product, while suppressing the formation of Al4C3 brittle phase, and the edge quality is better than that of the traditional process.

[0036] Example 2: Rolling of medium volume fraction (20%) SiCp / Al composite material (without edge banding) This embodiment uses SiCp / Al composite strip with a volume fraction of 20% and an average particle size of 10μm, with an initial thickness of 6.0mm, without edge pretreatment (without edge wrapping), to verify the rolling performance of medium volume fraction materials under edgeless conditions.

[0037] Parameter selection criteria: SiC particles in medium volume fraction materials have a certain hindering effect on eddy currents, so a medium frequency (5kHz) is selected to balance penetration depth and heating efficiency; the rolling speed is reduced to 25m / min to ensure that the matrix is ​​fully softened and to reduce the risk of edge cracking when there is no edge wrapping; and the reduction rate is set to achieve gradual deformation.

[0038] Process Specification Table: Results and Comparison with Traditional Processes: After 7 rolling passes, a finished strip with a thickness of 1.02 mm was obtained. The strip surface quality was good, but the lack of edging resulted in obvious burrs (width 0.5~0.8 mm) at the edges, and localized micro-cracks (length ≤1 mm). Finished product inspection results: tensile strength 370 MPa, elongation 4.0%, thickness tolerance ±0.018 mm; SiC particle integrity rate 94.8%, no Al4C3 brittle phase formation. When processing the same material using traditional processes, the finished product tensile strength is 312 MPa (15.7% lower than this embodiment), elongation 2.8% (30% lower than this embodiment), thickness tolerance ±0.048 mm (accuracy only 37.5% of this embodiment), SiC particle integrity rate 86.3% (8.9 percentage points lower than this embodiment), edge crack length reaches 2~3 mm, and obvious Al4C3 brittle phase is present.

[0039] Example of the invention: This example demonstrates that medium volume fraction (20%) SiCp / Al composite material can still be rolled using the method of the present invention without edge banding, and the finished product performance, dimensional accuracy and particle integrity are significantly better than those of the traditional process; it also shows that without edge banding, medium volume fraction material is prone to edge quality problems, providing a comparative basis for the necessity of subsequent edge banding process.

[0040] Example 3: Rolling of medium volume fraction (20%) SiCp / Al composite material (with edge wrapping) – Comparison with Example 2 This example is a comparative example of Example 2. It uses the same materials as Example 2 (SiCp / Al composite material with a volume fraction of 20% and an average particle size of 10μm), initial thickness (6.0mm), and rolling parameters. Only the edge pretreatment step is added (using nickel-plated copper strip for diffusion welding edge wrapping with an edge width of 5mm) to verify the effect of edge wrapping on improving rolling stability and edge quality.

[0041] Process Specification Table: Results and Comparison with Traditional Processes: After seven consecutive reversible rolling passes, a finished strip with a thickness of 1.02 mm was successfully obtained. Due to the edging, the edge stress of the strip was effectively dispersed during the rolling process, with no burrs or cracks, and the edges were smooth and flat. The strip exhibited uniform overall deformation and no surface defects. Testing revealed that the finished product had a tensile strength of 375 MPa (1.35% higher than Example 2), an elongation of 4.2% (5% higher than Example 2), and a thickness tolerance of ±0.016 mm. The SiC particle integrity rate was 95.5% (0.74% higher than Example 2), and no Al4C3 brittle phase was detected. Compared to traditional processes, this embodiment showed a 20.2% increase in tensile strength, a 50% increase in elongation, a 66.7% improvement in thickness tolerance, a 10.7 percentage point increase in SiC particle integrity, and an improvement in edge quality from "cracks + burrs" in traditional processes to "defect-free." The edge binding material is tightly bonded to the substrate, and the edge binding can be removed by simple cutting to obtain a high-precision finished strip.

[0042] Example Demonstration: The comparison between this example and Example 2 demonstrates that edge wrapping treatment can significantly improve the rolling edge quality of medium volume fraction SiCp / Al composite materials, while slightly improving the mechanical properties and particle integrity of the finished product. A comparison with traditional processes further proves that the combined scheme of "edge wrapping + medium-frequency online heating + reversible rolling" in this invention can comprehensively optimize the rolling effect of medium volume fraction materials, solving the problems of severe edge defects, poor performance, and low precision in traditional processes, and providing an effective solution for high-precision rolling of medium volume fraction materials.

[0043] Comparative Conclusion: A comparison between Example 2 and Example 3 shows that, under the same material and rolling parameters, the rolling scheme with edge wrapping can significantly improve edge quality, avoid burrs and cracks, and slightly improve the mechanical properties and particle integrity of the finished product. It is especially suitable for high-precision rolling of SiCp / Al composite materials with medium and high volume fractions.

[0044] Example 4: Rolling of medium-high volume fraction (30%) SiCp / Al composite material (with edge wrapping) This embodiment uses SiCp / Al composite strip with a volume fraction of 30% and an average particle size of 7μm, with an initial thickness of 4.0mm. Edge pretreatment (nickel-plated copper strip edge wrapping, edge width 5mm) is performed to verify the feasibility of rolling medium-high volume fraction materials under edge wrapping conditions.

[0045] Parameter selection criteria: In medium-to-high volume fraction materials, SiC particles have a high density and a significant effect on eddy current resistance. A higher frequency (8kHz) is selected to concentrate heat on the surface of the matrix and improve heating efficiency. The rolling speed is reduced to 20m / min, which, combined with a higher target temperature of 460℃, ensures that the matrix is ​​fully softened and avoids particle breakage. Edge stress is dispersed by edge wrapping to ensure rolling stability.

[0046] Process Specification Table: Results and comparison with traditional processes: The 7-pass rolling process was stable, with no jamming or abnormal shutdowns; the strip edges were smooth and defect-free due to edge protection, with no peeling. The finished product thickness was 0.68 mm. Test results: tensile strength 440 MPa, elongation 2.8%, thickness tolerance ±0.020 mm; SiC particle integrity rate 95.1%, no Al4C3 brittle phase detected, no peeling between the edge protection and the matrix, meeting the requirements for high-precision rolling. In traditional processes for processing high volume fraction (30%) SiCp / Al composite materials, uneven heating and stress concentration can easily lead to rolling fractures, resulting in a yield of only 45%. Even if rolling is successful, the tensile strength of the finished product is only 355 MPa (19.3% lower than in this example), the elongation is 1.9% (32.1% lower than in this example), the thickness tolerance is ±0.055 mm (the accuracy is only 36.4% of that in this example), the SiC particle integrity rate is 82.7% (13.1 percentage points lower than in this example), and the edge cracks are severe.

[0047] Example Demonstration: This example demonstrates that the "edge-wrapping + high-frequency online heating + low-speed progressive rolling" scheme of the present invention can achieve stable, efficient, and high-precision rolling of medium-to-high volume fraction (30%) SiCp / Al composite materials, solving the problems of low yield, poor performance, low precision, and severe edge defects in high volume fraction materials processed by traditional processes. It also demonstrates that the method of the present invention is adaptable to medium-to-high volume fractions up to 30%, expanding the application boundaries of SiCp / Al composite material rolling.

[0048] Example 5: Rolling of fine-particle (5μm) SiCp / Al composite material (with edge wrapping) This embodiment uses a fine-particle SiCp / Al composite strip with a volume fraction of 20% and an average particle size of 5μm, with an initial thickness of 3.0mm. Edge pretreatment (nickel-plated copper strip edge wrapping) is performed to verify the rolling efficiency and performance of the fine-particle material.

[0049] Parameter selection criteria: Fine-grained materials have a large specific surface area, more thorough interfacial bonding, and less resistance to matrix flow, which can increase the rolling speed to 35m / min; 4kHz medium frequency is selected to balance heating efficiency and penetration depth; edge-wrapping design ensures edge quality under high-speed rolling, and efficient rolling is achieved in conjunction with the set reduction rate.

[0050] Process Specification Table: Results and Comparison with Traditional Processes: The 7-pass high-speed rolling process was successfully completed, yielding an ultra-thin finished strip with a thickness of 0.51 mm. The strip edges were smooth, the surface was free of defects, and the deformation uniformity was good. Test results: tensile strength 390 MPa, elongation 4.2%, thickness tolerance ±0.015 mm; SiC particle integrity rate 96.3%, no Al4C3 brittle phase formation, achieving efficient and high-precision rolling of fine-grained materials. When processing the same fine-particle material using traditional processes, the uneven thermal conductivity of the fine particles is more pronounced, making localized overheating more likely during the heating process. This results in peeling of the finished product surface, a tensile strength of only 328 MPa (15.9% lower than in this embodiment), an elongation of 3.1% (26.2% lower than in this embodiment), a thickness tolerance of ±0.041 mm (accuracy only 36.6% of that in this embodiment), a SiC particle integrity rate of 89.2% (7.4 percentage points lower than in this embodiment), and a rolling speed of only 22 m / min (62.9% of that in this embodiment), leading to significantly lower production efficiency.

[0051] Example Demonstration: This example demonstrates that the method of the present invention has good adaptability to fine-particle (5μm) SiCp / Al composite materials, enabling high-speed rolling at 35m / min and significantly improving production efficiency. Simultaneously, the medium-frequency online heating method solves the problem of uneven thermal conductivity in fine-particle materials, avoiding localized overheating defects in traditional processes, and achieving higher finished product performance, dimensional accuracy, and particle integrity. The edge-wrapping design ensures edge quality under high-speed rolling, providing a feasible solution for efficient and high-precision rolling of fine-particle SiCp / Al composite materials.

[0052] Example 6: Rolling of thick (10.0 mm) SiCp / Al composite material (with edge wrapping) This embodiment uses SiCp / Al composite strip with a volume fraction of 15% and an average particle size of 8μm, with an initial thickness of 10.0mm. Edge pretreatment (nickel-plated copper strip edge wrapping) is performed to verify the feasibility of rolling thick-gauge materials.

[0053] Parameter selection criteria: For thick materials, it is necessary to ensure that the core is fully heated, so a lower frequency (3.5kHz) is selected to increase the eddy current penetration depth; the rolling speed is 40m / min to balance production efficiency and heating uniformity; the target temperature of 390℃ ensures that the matrix is ​​fully softened, and the edge is protected with edge wrapping to avoid cracking caused by stress concentration at the edge during the rolling of thick materials.

[0054] Process Specification Table: Results and Comparison with Traditional Processes: The 7-pass rolling process was stable, with the thickness gradually reduced to 1.69 mm. The strip edges were smooth, and the surface was free of defects such as cracks and peeling. Test Results: Tensile strength 350 MPa, elongation 4.2%, thickness tolerance ±0.017 mm; SiC particle integrity rate 95.0%, no Al4C3 brittle phase formation, proving that the method of this invention is applicable to the rolling of thick-gauge SiCp / Al composite materials. When processing 10.0mm thick SiCp / Al composite materials using traditional processes, insufficient heating of the core can easily lead to uneven deformation during rolling. The finished product has an edge crack width of 1-2mm and obvious surface unevenness. The finished product has a tensile strength of only 298MPa (14.9% lower than in this example), an elongation of 3.3% (21.4% lower than in this example), a thickness tolerance of ±0.045mm (accuracy of only 37.8% of this example), and a SiC particle integrity rate of 86.5% (8.9 percentage points lower than in this example). Moreover, the rolling cycle is 2.5 times longer than in this example.

[0055] Example Demonstration: This example demonstrates that the method of the present invention is applicable to the rolling of 10.0mm thick SiCp / Al composite materials. By employing a scheme of "low-frequency deep penetration heating + edge protection + uniform speed progressive rolling," it solves the problems of insufficient core heating, uneven deformation, severe edge defects, and long production cycles associated with traditional processes for thick materials. Furthermore, it demonstrates that the method of the present invention is not only suitable for thin materials but can also achieve high-precision and high-efficiency rolling of thick materials, further expanding its application scenarios.

[0056] The quantitative inspection methods in Examples 1-6 above are described as follows: The integrity of SiC particles was observed using a scanning electron microscope (SEM, model: Quanta 200 FEG). A field of view with a magnification of 500x was selected. More than 10 non-overlapping fields of view were uniformly selected along the thickness direction of the strip cross-section. The ratio of the number of intact SiC particles in each field of view to the total number of particles was calculated, and the average value of all fields of view was taken as the final particle integrity rate. The Al4C3 phase content was detected using an X-ray diffractometer (XRD, model: D8Advance). The test conditions were Cu target Kα rays (wavelength λ=1.5406Å), tube voltage 40kV, tube current 40mA, scanning range 2θ=10°~80°, scanning speed 8° / min. The diffraction pattern was quantitatively analyzed using MDI Jade 6.0 software combined with the Rietveld full-spectrum fitting method to calculate the mass fraction of the Al4C3 phase in the composite material. The interfacial bonding strength was determined according to the national standard GB / T. The interfacial bond strength of metal matrix composites was determined according to standard 30993-2014, "Determination of Interfacial Bond Strength of Metal Matrix Composites - Tensile Method". The sample size was 100 mm × 10 mm × 1 mm, the tensile rate was 0.5 mm / min, and each test group consisted of at least 5 parallel samples. The average value was taken as the final interfacial bond strength. Micropore density was determined by observing the cross-section of the strip using SEM (500x magnification), counting the number of micropores in 10 fields of view, and converting them to the unit area (mm²). 2 The number of holes in the cavity is calculated, and the average value is taken.

[0057] In summary, this invention creatively combines mid-frequency electromagnetic induction selective heating, reversible rolling online temperature compensation, and a central collaborative control system to construct a novel rolling technology solution for SiCp / Al composite materials. This solution is not only non-obvious but also achieves significant technical effects and industry breakthroughs, possessing high creative and industrial application value.

[0058] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A reversible rolling method for aluminum-based silicon carbide composite materials, characterized in that, Includes the following steps: S001. Provide an aluminum-based silicon carbide composite strip (8) to be rolled, the composite material comprising a conductive aluminum matrix and non-conductive or weakly conductive silicon carbide particles dispersed therein; S002. Before and / or during the rolling process of the strip (8) entering the reversible rolling mill (4), the metal components in the strip (8) are subjected to online induction heating by a medium frequency electromagnetic induction heating device (3); S003. The reversible rolling process includes at least one forward rolling pass and one backward rolling pass. When the strip (8) completes one pass and moves backward to perform the next pass, the strip is again heated online by the medium frequency electromagnetic induction heating device (3). S004. The central control system (7) receives the real-time temperature of the strip (8) and controls the heating power of the medium frequency electromagnetic induction heating device (3), the rolling speed and rolling force of the reversible rolling mill (4) in real time to stabilize the rolling.

2. The method according to claim 1, characterized in that, In step S002, the operating frequency of the medium-frequency electromagnetic induction coil for heating is 1-10kHz.

3. The method according to claim 1, characterized in that, In step S002, the heating rate of the medium-frequency electromagnetic induction heating is adjusted according to the thickness of the strip (8) and the rolling speed, and the heating rate is 20-100℃ / s.

4. The method according to claim 1, characterized in that, In step S004, the set rolling temperature range is 350℃-480℃. The rolling temperature refers to the temperature of the strip before it enters the rolls, specifically the temperature measured by an infrared thermometer before the strip enters the rolls.

5. The method according to claim 1, characterized in that, In step S004, the central control system (7) works in conjunction with the hydraulic automatic thickness control (AGC) system of the reversible rolling mill (4) to control the thickness tolerance of the finished strip within ±0.02mm by stabilizing the rolling temperature.

6. The method according to claim 1, characterized in that, Before step S001, the method further includes a step of pre-treating the edge of the aluminum-based silicon carbide composite strip (8), wherein the pre-treatment includes diffusion welding edge wrapping using nickel-plated copper strip.

7. The method according to claim 1, characterized in that, The volume fraction of silicon carbide particles in the aluminum-based silicon carbide composite material is 10% to 30%.

8. The method according to claim 1, characterized in that, In step S003, the reversible rolling process includes four forward rolling passes and three backward rolling passes, and the reduction rates of each pass in the hot rolling process are set sequentially as 35%, 30%, 25%, 20%, 17%, 15%, and 12%.

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