A method for manufacturing an aluminum-cast iron layered composite structure brake disc

Abstract

The application discloses a preparation method of an aluminum-cast iron layered composite structure brake disc and relates to the technical field of automobile brake systems. The brake disc is composed of an aluminum alloy layer and a cast iron layer through a hot-press forming process, the aluminum alloy layer mainly adopts aluminum-silicon alloy or aluminum-copper alloy, and the cast iron layer selects nodular cast iron or gray cast iron. Through optimization of the proportion of the aluminum alloy and the cast iron and the composite process, the application effectively realizes the lightweight of the brake disc, while the wear resistance and the thermal stability of the cast iron are retained. The composite structure not only improves the heat dissipation performance of the brake disc, reduces the performance degradation caused by high temperature, but also significantly reduces the overall weight of the brake disc, improves the brake efficiency and safety.

Description

Technical Field

[0001] This invention relates to the field of automotive braking system technology, and in particular to a method for preparing an aluminum-cast iron layered composite brake disc. Background Technology

[0002] Brake discs are the core component of a car's braking system, their main function being to slow or stop the vehicle's movement through friction with brake pads. With the improvement of vehicle performance, especially the rapid development of high-performance cars and electric vehicles, the performance requirements for braking systems have become increasingly stringent. Traditional cast iron brake discs, while possessing good wear resistance and thermal stability, are heavy due to their high density, affecting vehicle handling and fuel efficiency. In the modern automotive industry, reducing the weight of brake discs has become one of the key goals for improving vehicle performance.

[0003] Aluminum alloys, as lightweight materials, possess low density, good thermal conductivity, and corrosion resistance, making them a focus of research. However, when used alone as brake disc material, aluminum alloys lack sufficient wear resistance and thermal stability, failing to meet the demands of high-performance cars or racing cars during braking. Against this backdrop, composite structures of aluminum alloys and cast iron have become an important research direction, aiming to combine the lightweight properties of aluminum alloys with the wear resistance and thermal stability of cast iron.

[0004] In the research of aluminum alloy and cast iron composite brake discs, layered composite structures are considered an effective solution. Aluminum-cast iron layered composite brake discs, by combining aluminum alloy with cast iron layers, can provide excellent wear resistance, thermal stability, and heat dissipation while maintaining low weight. This technology not only reduces the overall weight of the vehicle and improves fuel efficiency but also enhances braking performance and strengthens the safety of the braking system.

[0005] Numerous studies and patented technologies have proposed different types of aluminum-cast iron composite brake discs. For example, patent CN106583654B discloses an aluminum alloy brake disc molten metal and a process for casting brake discs from it. The aluminum alloy brake disc molten metal involves sequentially impregnating silicon carbide particles in a strong alkaline aqueous solution and a potassium fluorozirconate aqueous solution, followed by a second impregnation. After the second impregnation, the particles are removed and dried to obtain a dried material, which is then mixed with liquid aluminum to obtain the molten metal. The process includes the following steps: preparing a metal mold for the aluminum alloy brake disc; pouring the molten metal into the cavity of the metal mold; and after cooling, removing the mold to obtain the aluminum alloy brake disc. The aluminum alloy brake disc obtained through the above molten metal and process exhibits uniform component distribution, good performance consistency, and good wear resistance.

[0006] Furthermore, patent application CN109295348A discloses a manufacturing process for a high-strength aluminum alloy brake disc, with the following specific steps: raw materials are added to a melting furnace and melted into a liquid aluminum alloy; the liquid aluminum alloy is cast into an aluminum alloy ingot; the aluminum alloy ingot is extruded into a solid extruded bar; the solid extruded bar undergoes carbonitriding treatment; the carbonitrided solid extruded bar undergoes offline quenching solution treatment; the solution-treated extruded bar undergoes artificial aging heat treatment; the aging extruded bar is precision-cut to length to produce the brake disc workpiece; the brake disc workpiece is immersed in an oxidation treatment solution in a treatment tank for oxidation treatment to obtain the high-strength aluminum alloy brake disc.

[0007] In addition, the patent with authorization announcement number CN102703771B introduces a method for preparing a silicon carbide / aluminum alloy composite material for brake discs. The technical solution is as follows: the matrix alloy is selected from cast aluminum alloy ZAlSi8MgBe, and the silicon carbide is selected from α-SiC particles. The specific preparation includes the following steps: (1) SiC particle shaping, (2) hydrochloric acid pickling, (3) high temperature oxidation, (4) nitrate sensitization, (5) stirring casting, and (6) T6 heat treatment.

[0008] Despite some progress in the research of aluminum-cast iron composite brake discs, numerous challenges remain. Key issues include: how to further optimize the bonding process between aluminum alloy and cast iron; how to improve the thermal shock resistance of the composite structure; and how to reduce production costs while improving performance. Existing composite structures typically require complex manufacturing processes and may experience interlayer delamination under high temperature and high load conditions, limiting their widespread application. Summary of the Invention

[0009] Based on the problems raised in the background art, the present invention proposes a method for preparing an aluminum-cast iron layered composite brake disc.

[0010] The technical solution is as follows:

[0011] A method for preparing an aluminum-cast iron layered composite brake disc includes the following steps:

[0012] a) Select aluminum alloy and cast iron as raw materials, wherein the mass fraction of aluminum alloy is 30%-50% of the total mass, and the mass fraction of cast iron is 50%-70% of the total mass;

[0013] b) Pre-treat the aluminum alloy and cast iron.

[0014] Pretreatment and preparation stage: Femtosecond laser etching equipment is used to etch the contact surface between the cast iron layer and the aluminum alloy, and to process a composite microtexture of honeycomb micro-pits and annular micro-grooves. After etching, 400W, 20s argon plasma cleaning is used to remove residues and activate the surface activity of the cast iron.

[0015] Simultaneously, a multi-component synergistic penetrant is prepared according to the mass ratio, specifically Ti 35%-40%, B 25%-30%, Ce-La composite rare earth 5%-8%, V-Nb composite 15%-20%, and Zr 5%-7%, and mixed and ground to a particle size of 30-50nm to ensure uniform dispersion.

[0016] c) Filling and lamination stage: The multi-component synergistic penetrant is filled into the pits and grooves of the composite microtexture of the cast iron layer, and treated with 40kHz ultrasonic vibration for 5 minutes to eliminate powder agglomeration and achieve full coverage; then the cast iron layer filled with multi-component synergistic penetrant is laminated with the surface-cleaned aluminum alloy layer to ensure that the two layers are initially tightly bonded.

[0017] d) Molding, cooling and testing stage: The laminated composite blank is placed into a hot press mold, and the hot pressing temperature and pressure are set. During the heat preservation process, the low melting point Al-B-Ti-Zr eutectic phase melts and the interface wetting angle is reduced to below 40°. Then, high temperature aging treatment is carried out to form a 180-280μm gradient functional diffusion layer. After high temperature aging, water cooling or air cooling is used. After cooling is completed, the finished product is quality inspected.

[0018] In the above method, the aluminum alloy is an aluminum-silicon alloy with a silicon content of 9%-12% by mass and a thickness of 2.5mm to 4mm for the aluminum alloy layer.

[0019] In the above method, the cast iron is ductile iron or gray cast iron, and the thickness of the cast iron layer is 8mm to 12mm.

[0020] In the above method, the honeycomb-shaped micro-pits have a diameter of 60-100μm, a depth of 40-60μm, and a spacing of 180-220μm; the annular microgrooves have a width of 10-15μm, a depth of 15-20μm, and are radially distributed around the micro-pits.

[0021] In the above method, the amount of the multi-component synergistic penetrant added is 0.8%-1.2% of the total mass.

[0022] In the above method, the lamination speed is 1-3 mm / s.

[0023] In the above method, the hot pressing temperature is 300-450℃.

[0024] In the above method, the hot pressing pressure is 5-10 MPa.

[0025] In the above method, the high-temperature aging temperature is 450-450℃, and the time is 3 to 5 hours.

[0026] In the above method, the air cooling time is 2 to 6 hours.

[0027] Reaction Mechanism: This invention utilizes the synergistic effect of a multi-component synergistic penetrant and a composite microtexture to construct a triple interfacial mechanism of "mechanical interlocking - metallurgical bonding - dispersion strengthening," fundamentally improving the aluminum-iron interfacial bonding problem. The composite microtexture provides a storage and attachment carrier for the penetrant, while argon plasma cleaning activates the surface activity of cast iron, laying the foundation for element diffusion. During the hot pressing stage, the melting of the low-melting-point Al-B-Ti-Zr eutectic phase reduces the interfacial wetting angle, promoting the fusion of the aluminum and iron matrix interfaces. During high-temperature aging, Ti and B elements in the penetrant accelerate the interdiffusion of Al and Fe atoms, inhibiting the excessive formation of the brittle Fe3Al phase. Rare earth Ce-La plays a regulatory role, optimizing the interfacial phase composition and distribution, and improving phase structure stability. Zr combines with C in the matrix to form ZrC nanoparticles, which, together with V4C3 and NbC, form a multi-component dispersion strengthening phase, uniformly distributed in the interfacial diffusion layer and matrix, strengthening the interfacial bonding strength and matrix mechanical properties. Simultaneously, it synergistically improves the material's friction and wear characteristics and thermal conductivity efficiency, avoiding interfacial peeling or performance degradation at high temperatures.

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] 1. Enhanced interfacial bonding and structural stability: By leveraging the synergistic effect of multiple penetrants and the mechanical anchoring effect of composite microtexture, a robust interfacial bonding system is constructed, effectively suppressing the formation of brittle phases, enhancing the thermal shock resistance of the composite structure, avoiding interlayer delamination and structural deformation under high temperature and high load, and ensuring the service stability of the brake disc.

[0030] 2. Optimize the synergistic performance of friction, wear and heat dissipation: The multi-component dispersed reinforcing phase significantly improves the wear resistance of the material and reduces the degree of wear during the friction process; the excellent thermal conductivity of the aluminum alloy layer and the optimized thermal conduction efficiency of the interface accelerate the dissipation of heat during braking, alleviate the problem of excessive temperature rise, and avoid brake fade.

[0031] 3. Achieving a balance between lightweight design and service reliability: The layered composite design of aluminum alloy and cast iron takes into account both lightweight requirements and structural strength. The multi-component penetrant gives the material better comprehensive mechanical properties, which reduces the weight of the brake disc, improves vehicle handling and energy efficiency, extends the service life of the brake disc, and reduces maintenance costs. Detailed Implementation

[0032] The present invention will be further illustrated below with reference to specific implementation examples. These examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0033] Example 1: A method for preparing an aluminum-cast iron layered composite brake disc, comprising the following steps:

[0034] a) Raw material selection: Aluminum-silicon alloy (aluminum alloy) and ductile iron are selected as raw materials, with a total mass of 200kg; of which aluminum alloy accounts for 60kg (30% of the total mass), silicon content is 9%, and the aluminum alloy layer is designed to be 2.5mm thick; cast iron accounts for 140kg (70% of the total mass), and the cast iron layer is designed to be 8mm thick.

[0035] b) Pretreatment and preparation stage: A femtosecond laser etching device (output power 10W, pulse frequency 1kHz, spot diameter 50μm) was used to etch the surface where the cast iron layer contacts the aluminum alloy, processing a composite microtexture of honeycomb-shaped micro-pits and annular micro-grooves; the honeycomb-shaped micro-pits are 60μm in diameter and 40μm in depth, with a pit spacing of 180μm; the annular micro-grooves are 10μm wide and 15μm deep, and are radially and uniformly distributed around each micro-pit (each pit is equipped with 4 grooves). After etching, the cast iron part is placed in a plasma cleaning machine and cleaned with 400W argon plasma for 20s to remove surface etching residues and activate the surface activity of the cast iron. After cleaning, it is taken out and dried for later use. Simultaneously, a multi-component synergistic penetrant was prepared, with an addition amount of 0.8% (1.6 kg) of the total mass. The mass percentages of each component (total 100%) were as follows: Ti 35%, B 30%, Ce-La composite rare earth 8%, V-Nb composite 20%, and Zr 7%. The above mixed raw materials were fed into a planetary ball mill and ground into nano-composite powder with a particle size of 30 nm. Anhydrous ethanol was added as a dispersion medium during the grinding process (solid-liquid ratio 1:2). After grinding, the medium was removed by vacuum drying (60℃, 2 h) to ensure uniform powder dispersion. The powder was then ready for use.

[0036] c) Filling and Lamination Stage: The ground penetrant nanopowder is evenly sprinkled into the pits and grooves of the cast iron composite microtexture. The cast iron is then placed in an ultrasonic cleaner and treated with 40kHz ultrasonic vibration for 5 minutes to eliminate powder agglomeration and ensure dense, full coverage without gaps within the microtexture. The cleaned aluminum alloy layer (wiped with acetone and dried) is aligned with the cast iron layer bonding surface and fed into a laminator. The lamination speed is set to 1mm / s, and an initial pressure of 2MPa is applied to complete the lamination operation, ensuring a tight initial bond between the two layers without bubbles or gaps.

[0037] d) Molding, Cooling, and Testing Stage: The laminated composite blank is placed into a hot press mold (made of H13 steel, with a release agent coated on the inner wall). After closing the mold, it is sent to a hot press molding machine. The hot pressing temperature is set to 300℃, the hot pressing pressure to 5MPa, and the heating rate to 5℃ / min. After reaching the set temperature, it is held for 2 hours. During the holding process, the low-melting-point Al-B-Ti-Zr eutectic phase melts, reducing the interfacial wetting angle to below 40°. Subsequently, high-temperature aging treatment is performed. The mold and blank are transferred to an aging furnace, and the aging temperature is set to 450℃ for 3 hours. During the holding process, the interdiffusion of elements such as Al, Fe, Ti, and Zr is promoted, forming a 180μm thick gradient functional diffusion layer. After high-temperature aging, air cooling is used for 2 hours. During the cooling process, the cooling rate is controlled at 3℃ / min to avoid excessive temperature difference and stress. After cooling to room temperature, remove the finished brake disc and conduct quality inspection on the finished product: test the interface bonding strength (using tensile test, requiring ≥35MPa), hardness (aluminum alloy layer ≥80HB, cast iron layer ≥220HB), dimensional accuracy (thickness deviation ±0.1mm) and appearance (no cracks, deformation, pores and other defects). If all indicators are qualified, it is a finished product.

[0038] Example 2: A method for preparing an aluminum-cast iron layered composite brake disc, comprising the following steps:

[0039] a) Raw material selection: Aluminum-silicon alloy (aluminum alloy) and gray cast iron are selected as raw materials, with a total mass of 200kg; of which aluminum alloy accounts for 75kg (37.5% of the total mass), silicon content is 10%, and the aluminum alloy layer is designed to be 3.0mm thick; cast iron accounts for 125kg (62.5% of the total mass), and the cast iron layer is designed to be 9.5mm thick.

[0040] b) Pretreatment and preparation stage: A femtosecond laser etching device (output power 12W, pulse frequency 1.2kHz, spot diameter 55μm) was used to etch the surface where the cast iron layer contacts the aluminum alloy, processing a composite microtexture of honeycomb-shaped micro-pits and annular micro-grooves; the honeycomb-shaped micro-pits are 75μm in diameter and 45μm in depth, with a pit spacing of 190μm; the annular micro-grooves are 12μm wide and 17μm deep, and are radially and uniformly distributed around each micro-pit (5 grooves per pit). After etching, the cast iron part is placed in a plasma cleaning machine and cleaned with 400W argon plasma for 20s to remove surface etching residues and activate the surface activity of the cast iron. After cleaning, it is taken out and dried for later use. Simultaneously, a multi-component synergistic penetrant was prepared, with an addition amount of 0.9% (1.8 kg) of the total mass. The mass percentages of each component (total 100%) were as follows: Ti 40%, B 28%, Ce-La 7%, V-Nb 18%, and Zr 7%. The above mixed raw materials were fed into a planetary ball mill and ground into nanocomposite powder with a particle size of 35 nm. Anhydrous ethanol was added as a dispersion medium during the grinding process (solid-liquid ratio 1:2.5). After grinding, the medium was removed by vacuum drying (65℃, 2.5 h) to ensure uniform powder dispersion. The powder was then ready for use.

[0041] c) Filling and Lamination Stage: The ground penetrant nanopowder is evenly sprinkled into the pits and grooves of the cast iron composite microtexture. The cast iron part is then placed in an ultrasonic cleaner and treated with ultrasonic vibration at 40kHz for 5 minutes to eliminate powder agglomeration and ensure dense, complete coverage without gaps within the microtexture. The cleaned aluminum alloy layer (wiped with acetone and dried) is aligned with the bonding surface of the cast iron layer and fed into a laminator. The lamination speed is set to 1.75mm / s, and an initial pressure of 2.5MPa is applied to complete the lamination operation, ensuring a tight initial bond between the two layers without air bubbles or gaps.

[0042] d) Molding, Cooling, and Testing Stage: The laminated composite blank is placed into a hot press mold (made of H13 steel, with a release agent coated on the inner wall). After closing the mold, it is sent to a hot press molding machine. The hot pressing temperature is set to 350℃, the hot pressing pressure to 6.5MPa, and the heating rate to 6℃ / min. After reaching the set temperature, it is held for 2.5 hours. During the holding process, the low-melting-point Al-B-Ti-Zr eutectic phase melts, reducing the interfacial wetting angle to below 40°. Subsequently, high-temperature aging treatment is performed. The mold and blank are transferred to an aging furnace, and the aging temperature is set to 450℃ for 3.5 hours. During the holding process, the interdiffusion of elements such as Al, Fe, Ti, and Zr is promoted, forming a 220μm thick gradient functional diffusion layer. After high-temperature aging, air cooling is used for 3.5 hours. During the cooling process, the cooling rate is controlled at 2.5℃ / min to avoid excessive temperature difference and stress. After cooling to room temperature, remove the finished brake disc and conduct quality inspection on the finished product: test the interface bonding strength (using tensile test, requiring ≥35MPa), hardness (aluminum alloy layer ≥85HB, cast iron layer ≥225HB), dimensional accuracy (thickness deviation ±0.1mm) and appearance (no cracks, deformation, pores and other defects). If all indicators are qualified, it is a finished product.

[0043] Example 3: A method for preparing an aluminum-cast iron layered composite brake disc, comprising the following steps:

[0044] a) Raw material selection: Aluminum-silicon alloy (aluminum alloy) and ductile iron + gray cast iron (mixed in a mass ratio of 1:1) are selected as raw materials, with a total mass of 200kg; of which aluminum alloy accounts for 90kg (45% of the total mass), silicon content is 11%, and the aluminum alloy layer is designed to be 3.5mm thick; cast iron accounts for 110kg (55% of the total mass), and the cast iron layer is designed to be 11mm thick.

[0045] b) Pretreatment and preparation stage: A femtosecond laser etching device (output power 15W, pulse frequency 1.5kHz, spot diameter 60μm) was used to etch the surface where the cast iron layer contacts the aluminum alloy, processing a composite microtexture of honeycomb-shaped micro-pits and annular micro-grooves; the honeycomb-shaped micro-pits are 90μm in diameter and 55μm in depth, with a pit spacing of 210μm; the annular micro-grooves are 14μm wide and 19μm deep, and are radially and uniformly distributed around each micro-pit (each pit is equipped with 5 grooves). After etching, the cast iron part is placed in a plasma cleaning machine and cleaned with 400W argon plasma for 20s to remove surface etching residues and activate the surface activity of the cast iron. After cleaning, it is taken out and dried for later use. Simultaneously, a multi-component synergistic penetrant was prepared, with an addition amount of 1.1% (2.2 kg) of the total mass. The mass percentages of each component (total 100%) were as follows: Ti 38%, B 29%, Ce-La composite rare earth 8%, V-Nb composite 19%, and Zr 6%. The above mixed raw materials were fed into a planetary ball mill and ground into nano-composite powder with a particle size of 45 nm. Anhydrous ethanol was added as a dispersion medium during the grinding process (solid-liquid ratio 1:3). After grinding, the medium was removed by vacuum drying (70℃, 3 h) to ensure uniform powder dispersion. The powder was then ready for use.

[0046] c) Filling and Lamination Stage: The ground penetrant nanopowder is evenly sprinkled into the pits and grooves of the cast iron composite microtexture. The cast iron part is then placed in an ultrasonic cleaner and treated with ultrasonic vibration at 40kHz for 5 minutes to eliminate powder agglomeration and ensure dense, full coverage without gaps within the microtexture. The cleaned aluminum alloy layer (wiped with acetone and dried) is aligned with the cast iron layer bonding surface and fed into a laminator. The lamination speed is set to 2.5mm / s, and an initial pressure of 3MPa is applied to complete the lamination operation, ensuring a tight initial bond between the two layers without air bubbles or gaps.

[0047] d) Molding, Cooling, and Testing Stage: The laminated composite blank is placed into a hot press mold (made of H13 steel, with a release agent coated on the inner wall). After closing the mold, it is sent to a hot press molding machine. The hot pressing temperature is set to 400℃, the hot pressing pressure to 8.5MPa, and the heating rate to 7℃ / min. After reaching the set temperature, it is held for 3 hours. During the holding process, the low-melting-point Al-B-Ti-Zr eutectic phase melts, reducing the interfacial wetting angle to below 40°. Subsequently, high-temperature aging treatment is performed. The mold and blank are transferred to an aging furnace, and the aging temperature is set to 450℃ for 4.5 hours. During the holding process, the interdiffusion of elements such as Al, Fe, Ti, and Zr is promoted, forming a 260μm thick gradient functional diffusion layer. After high-temperature aging, air cooling is used for 5 hours. During the cooling process, the cooling rate is controlled at 2℃ / min to avoid excessive temperature difference and stress. After cooling to room temperature, remove the finished brake disc and conduct quality inspection on the finished product: test the interface bonding strength (using tensile test, requiring ≥35MPa), hardness (aluminum alloy layer ≥90HB, cast iron layer ≥230HB), dimensional accuracy (thickness deviation ±0.1mm) and appearance (no cracks, deformation, pores and other defects). If all indicators are qualified, it is a finished product.

[0048] Example 4: A method for preparing an aluminum-cast iron layered composite brake disc, comprising the following steps:

[0049] a) Raw material selection: Aluminum-silicon alloy (aluminum alloy) and ductile iron + gray cast iron (mixed in a mass ratio of 2:1) are selected as raw materials, with a total mass of 200kg; of which aluminum alloy accounts for 100kg (50% of the total mass), silicon content is 12%, and the aluminum alloy layer is designed to be 4.0mm thick; cast iron accounts for 100kg (50% of the total mass), and the cast iron layer is designed to be 12mm thick.

[0050] b) Pretreatment and Preparation Stage: A femtosecond laser etching device (output power 18W, pulse frequency 2kHz, spot diameter 65μm) was used to etch the surface where the cast iron layer contacts the aluminum alloy, creating a composite microtexture of honeycomb-shaped micro-pits and annular micro-grooves. The honeycomb-shaped micro-pits are 100μm in diameter and 60μm deep, with a pit spacing of 220μm. The annular micro-grooves are 15μm wide and 20μm deep, radially and uniformly distributed around each micro-pit (6 grooves per pit). After etching, the cast iron part is placed in a plasma cleaner and cleaned with 400W argon plasma for 20 seconds to remove surface etching residues and activate the surface activity of the cast iron. After cleaning, it is removed and dried for later use. Simultaneously, a multi-component synergistic penetrant was prepared, with an addition amount of 1.2% (2.4 kg) of the total mass. The mass percentages of each component (total 100%) were as follows: Ti 40%, B 30%, Ce-La composite rare earth 8%, V-Nb composite 15%, and Zr 7%. The above mixed raw materials were fed into a planetary ball mill and ground into nano-composite powder with a particle size of 50 nm. Anhydrous ethanol was added as a dispersion medium during the grinding process (solid-liquid ratio 1:3.5). After grinding, the medium was removed by vacuum drying (75℃, 3.5 h) to ensure uniform powder dispersion.

[0051] c) Filling and Lamination Stage: The ground penetrant nanopowder is evenly sprinkled into the pits and grooves of the cast iron composite microtexture. The cast iron part is then placed in an ultrasonic cleaner and treated with ultrasonic vibration at 40kHz for 5 minutes to eliminate powder agglomeration and ensure dense, full coverage without gaps within the microtexture. The cleaned aluminum alloy layer (wiped with acetone and dried) is aligned with the bonding surface of the cast iron layer and fed into a laminator. The lamination speed is set to 3mm / s, and an initial pressure of 3.5MPa is applied to complete the lamination operation, ensuring a tight initial bond between the two layers without bubbles or gaps.

[0052] d) Molding, Cooling, and Testing Stage: The laminated composite blank is placed into a hot press mold (made of H13 steel, with a release agent coated on the inner wall). After closing the mold, it is sent to a hot press molding machine. The hot pressing temperature is set to 450℃, the hot pressing pressure to 10MPa, and the heating rate to 8℃ / min. After reaching the set temperature, it is held for 3.5 hours. During the holding process, the low-melting-point Al-B-Ti-Zr eutectic phase melts, reducing the interfacial wetting angle to below 40°. Subsequently, high-temperature aging treatment is performed. The mold and blank are transferred to an aging furnace, and the aging temperature is set to 450℃ for 5 hours. During the holding process, the interdiffusion of elements such as Al, Fe, Ti, and Zr is promoted, forming a 280μm thick gradient functional diffusion layer. After high-temperature aging, air cooling is used for 6 hours, with the cooling rate controlled at 1.5℃ / min to avoid excessive temperature difference and stress. After cooling to room temperature, remove the finished brake disc and conduct quality inspection on the finished product: test the interface bonding strength (using tensile test, requiring ≥35MPa), hardness (aluminum alloy layer ≥95HB, cast iron layer ≥235HB), dimensional accuracy (thickness deviation ±0.1mm) and appearance (no cracks, deformation, pores and other defects). If all indicators are qualified, it is a finished product.

[0053] Comparative Example 1: A method for preparing an aluminum-cast iron layered composite brake disc, comprising the following steps:

[0054] a) Raw material selection: Aluminum-silicon alloy (aluminum alloy) and ductile iron are selected as raw materials, with a total mass of 200kg; of which aluminum alloy accounts for 60kg (30% of the total mass), silicon content is 9%, and the aluminum alloy layer is designed to be 2.5mm thick; cast iron accounts for 140kg (70% of the total mass), and the cast iron layer is designed to be 8mm thick.

[0055] b) Pretreatment and Preparation Stage: A femtosecond laser etching device (output power 10W, pulse frequency 1kHz, spot diameter 50μm) was used to etch the surface of the cast iron layer in contact with the aluminum alloy, processing a composite microtexture of honeycomb-shaped micro-pits and annular micro-grooves; the honeycomb-shaped micro-pits are 60μm in diameter and 40μm in depth, with a pit spacing of 180μm; the annular micro-grooves are 10μm wide and 15μm deep, radially and uniformly distributed around each micro-pit (each pit is equipped with 4 grooves). After etching, the cast iron parts were placed in a plasma cleaner and cleaned with 400W argon plasma for 20s to remove surface etching residues and activate the surface activity of the cast iron. After cleaning, they were removed and dried for later use. The above mixed raw materials were fed into a planetary ball mill and ground into nanocomposite powder with a particle size of 30nm. Anhydrous ethanol was added as a dispersion medium during the grinding process (solid-liquid ratio 1:2). After grinding, the medium was removed by vacuum drying (60℃, 2h) to ensure uniform powder dispersion for later use.

[0056] c) Filling and Lamination Stage: The ground penetrant nanopowder is evenly sprinkled into the pits and grooves of the cast iron composite microtexture. The cast iron is then placed in an ultrasonic cleaner and treated with 40kHz ultrasonic vibration for 5 minutes to eliminate powder agglomeration and ensure dense, full coverage without gaps within the microtexture. The cleaned aluminum alloy layer (wiped with acetone and dried) is aligned with the cast iron layer bonding surface and fed into a laminator. The lamination speed is set to 1mm / s, and an initial pressure of 2MPa is applied to complete the lamination operation, ensuring a tight initial bond between the two layers without bubbles or gaps.

[0057] d) Molding, Cooling, and Testing Stage: The laminated composite blank is placed into a hot press mold (made of H13 steel, with a release agent coated on the inner wall). After closing the mold, it is sent to a hot press molding machine. The hot pressing temperature is set to 300℃, the hot pressing pressure to 5MPa, and the heating rate to 5℃ / min. After reaching the set temperature, it is held for 2 hours. During the holding process, the low-melting-point Al-B-Ti-Zr eutectic phase melts, reducing the interfacial wetting angle to below 40°. Subsequently, high-temperature aging treatment is performed. The mold and blank are transferred to an aging furnace, and the aging temperature is set to 450℃ for 3 hours. During the holding process, the interdiffusion of elements such as Al, Fe, Ti, and Zr is promoted, forming a 180μm thick gradient functional diffusion layer. After high-temperature aging, air cooling is used for 2 hours. During the cooling process, the cooling rate is controlled at 3℃ / min to avoid excessive temperature difference and stress. After cooling to room temperature, remove the finished brake disc and conduct quality inspection on the finished product: test the interface bonding strength (using tensile test, requiring ≥35MPa), hardness (aluminum alloy layer ≥80HB, cast iron layer ≥220HB), dimensional accuracy (thickness deviation ±0.1mm) and appearance (no cracks, deformation, pores and other defects). If all indicators are qualified, it is a finished product.

[0058] Comparative Example 2: A method for preparing an aluminum-cast iron layered composite brake disc, comprising the following steps:

[0059] a) Raw material selection: Aluminum-silicon alloy (aluminum alloy) and ductile iron are selected as raw materials, with a total mass of 200kg; of which aluminum alloy accounts for 60kg (30% of the total mass), silicon content is 9%, and the aluminum alloy layer is designed to be 2.5mm thick; cast iron accounts for 140kg (70% of the total mass), and the cast iron layer is designed to be 8mm thick.

[0060] b) Pretreatment and preparation stage: A femtosecond laser etching device (output power 10W, pulse frequency 1kHz, spot diameter 50μm) was used to etch the surface where the cast iron layer contacts the aluminum alloy, processing a composite microtexture of honeycomb-shaped micro-pits and annular micro-grooves; the honeycomb-shaped micro-pits are 60μm in diameter and 40μm in depth, with a pit spacing of 180μm; the annular micro-grooves are 10μm wide and 15μm deep, and are radially and uniformly distributed around each micro-pit (each pit is equipped with 4 grooves). After etching, the cast iron part is placed in a plasma cleaning machine and cleaned with 400W argon plasma for 20s to remove surface etching residues and activate the surface activity of the cast iron. After cleaning, it is taken out and dried for later use. Simultaneously, a multi-component synergistic penetrant was prepared, with an addition amount of 0.8% (1.6 kg) of the total mass. The mass percentages of each component (total 100%) were as follows: Ti 35%, B 38%, V-Nb composite 20%, and Zr 7%. The above mixed raw materials were fed into a planetary ball mill and ground into nanocomposite powder with a particle size of 30 nm. Anhydrous ethanol was added as a dispersion medium during the grinding process (solid-liquid ratio 1:2). After grinding, the medium was removed by vacuum drying (60℃, 2 h) to ensure uniform powder dispersion. The powder was then ready for use.

[0061] c) Filling and Lamination Stage: The ground penetrant nanopowder is evenly sprinkled into the pits and grooves of the cast iron composite microtexture. The cast iron is then placed in an ultrasonic cleaner and treated with 40kHz ultrasonic vibration for 5 minutes to eliminate powder agglomeration and ensure dense, full coverage without gaps within the microtexture. The cleaned aluminum alloy layer (wiped with acetone and dried) is aligned with the cast iron layer bonding surface and fed into a laminator. The lamination speed is set to 1mm / s, and an initial pressure of 2MPa is applied to complete the lamination operation, ensuring a tight initial bond between the two layers without bubbles or gaps.

[0062] d) Molding, Cooling, and Testing Stage: The laminated composite blank is placed into a hot press mold (made of H13 steel, with a release agent coated on the inner wall). After closing the mold, it is sent to a hot press molding machine. The hot pressing temperature is set to 300℃, the hot pressing pressure to 5MPa, and the heating rate to 5℃ / min. After reaching the set temperature, it is held for 2 hours. During the holding process, the low-melting-point Al-B-Ti-Zr eutectic phase melts, reducing the interfacial wetting angle to below 40°. Subsequently, high-temperature aging treatment is performed. The mold and blank are transferred to an aging furnace, and the aging temperature is set to 450℃ for 3 hours. During the holding process, the interdiffusion of elements such as Al, Fe, Ti, and Zr is promoted, forming a 180μm thick gradient functional diffusion layer. After high-temperature aging, air cooling is used for 2 hours. During the cooling process, the cooling rate is controlled at 3℃ / min to avoid excessive temperature difference and stress. After cooling to room temperature, remove the finished brake disc and conduct quality inspection on the finished product: test the interface bonding strength (using tensile test, requiring ≥35MPa), hardness (aluminum alloy layer ≥80HB, cast iron layer ≥220HB), dimensional accuracy (thickness deviation ±0.1mm) and appearance (no cracks, deformation, pores and other defects). If all indicators are qualified, it is a finished product.

[0063] Comparative Example 3: A method for preparing an aluminum-cast iron layered composite brake disc, comprising the following steps:

[0064] a) Raw material selection: Aluminum-silicon alloy (aluminum alloy) and ductile iron are selected as raw materials, with a total mass of 200kg; of which aluminum alloy accounts for 60kg (30% of the total mass), silicon content is 9%, and the aluminum alloy layer is designed to be 2.5mm thick; cast iron accounts for 140kg (70% of the total mass), and the cast iron layer is designed to be 8mm thick.

[0065] b) Pretreatment and preparation stage: A femtosecond laser etching device (output power 10W, pulse frequency 1kHz, spot diameter 50μm) was used to etch the surface where the cast iron layer contacts the aluminum alloy, processing a composite microtexture of honeycomb-shaped micro-pits and annular micro-grooves; the honeycomb-shaped micro-pits are 60μm in diameter and 40μm in depth, with a pit spacing of 180μm; the annular micro-grooves are 10μm wide and 15μm deep, and are radially and uniformly distributed around each micro-pit (each pit is equipped with 4 grooves). After etching, the cast iron part is placed in a plasma cleaning machine and cleaned with 400W argon plasma for 20s to remove surface etching residues and activate the surface activity of the cast iron. After cleaning, it is taken out and dried for later use. Simultaneously, a multi-component synergistic penetrant was prepared, with an addition amount of 0.8% (1.6 kg) of the total mass. The mass percentages of each component (total 100%) were as follows: Ti 35%, B 30%, Ce-La composite rare earth 8%, and Zr 27%. The above mixed raw materials were fed into a planetary ball mill and ground into nano-composite powder with a particle size of 30 nm. Anhydrous ethanol was added as a dispersion medium during the grinding process (solid-liquid ratio 1:2). After grinding, the medium was removed by vacuum drying (60℃, 2 h) to ensure uniform powder dispersion. The powder was then ready for use.

[0066] c) Filling and Lamination Stage: The ground penetrant nanopowder is evenly sprinkled into the pits and grooves of the cast iron composite microtexture. The cast iron is then placed in an ultrasonic cleaner and treated with 40kHz ultrasonic vibration for 5 minutes to eliminate powder agglomeration and ensure dense, full coverage without gaps within the microtexture. The cleaned aluminum alloy layer (wiped with acetone and dried) is aligned with the cast iron layer bonding surface and fed into a laminator. The lamination speed is set to 1mm / s, and an initial pressure of 2MPa is applied to complete the lamination operation, ensuring a tight initial bond between the two layers without bubbles or gaps.

[0067] d) Molding, Cooling, and Testing Stage: The laminated composite blank is placed into a hot press mold (made of H13 steel, with a release agent coated on the inner wall). After closing the mold, it is sent to a hot press molding machine. The hot pressing temperature is set to 300℃, the hot pressing pressure to 5MPa, and the heating rate to 5℃ / min. After reaching the set temperature, it is held for 2 hours. During the holding process, the low-melting-point Al-B-Ti-Zr eutectic phase melts, reducing the interfacial wetting angle to below 40°. Subsequently, high-temperature aging treatment is performed. The mold and blank are transferred to an aging furnace, and the aging temperature is set to 450℃ for 3 hours. During the holding process, the interdiffusion of elements such as Al, Fe, Ti, and Zr is promoted, forming a 180μm thick gradient functional diffusion layer. After high-temperature aging, air cooling is used for 2 hours. During the cooling process, the cooling rate is controlled at 3℃ / min to avoid excessive temperature difference and stress. After cooling to room temperature, remove the finished brake disc and conduct quality inspection on the finished product: test the interface bonding strength (using tensile test, requiring ≥35MPa), hardness (aluminum alloy layer ≥80HB, cast iron layer ≥220HB), dimensional accuracy (thickness deviation ±0.1mm) and appearance (no cracks, deformation, pores and other defects). If all indicators are qualified, it is a finished product.

[0068] Test method:

[0069] 1. Abrasion resistance test:

[0070] Wear tests were conducted using a friction and wear testing machine under different braking loads and speeds. The coefficient of friction and wear between the brake disc and brake pads were recorded and compared.

[0071] Test conditions: load 50N, speed 300rpm, wear time 2 hours.

[0072] 2. Thermal stability test:

[0073] Thermal cycling tests simulate the operation of brake discs at high temperatures. The brake discs are subjected to 500 high-temperature cycles using a thermal cycling tester, with temperatures ranging from room temperature to 500°C. Performance changes, such as cracks and deformation, are recorded after each cycle.

[0074] 3. Heat dissipation performance test:

[0075] Infrared thermal imagers are used to monitor the dynamic heat distribution of brake discs, measure the heat distribution during high-speed braking, and observe the rate of temperature rise and heat dissipation effect of the brake discs.

[0076] Test conditions: The surface temperature and heat dissipation effect of the brake disc were measured after 500 consecutive braking cycles.

[0077] Table 1: Test results of each embodiment and comparative example

[0078]

[0079] The test results show that the multi-component synergistic penetrant system used in this invention plays a key role in improving the overall performance of the brake disc. Compared with the comparative example, the product of this embodiment shows significant advantages in wear control, thermal stability, and heat dissipation efficiency. The ZrC, V4C3, and NbC multi-component dispersed reinforcing phases in the penetrant effectively improve the material's hardness and wear resistance, reducing wear during friction and significantly lowering the degree of wear. The rare earth Ce-La composite component, by regulating the interfacial phase structure, inhibits the initiation and propagation of brittle phases and cracks. Combined with the metallurgical bonding effect promoted by Ti and B elements, it enhances the thermal stability of the composite structure, ensuring no cracks or deformation after high-temperature cycling. Simultaneously, boron and titanium synergistically improve interfacial wetting and element diffusion efficiency, making the interfacial diffusion layer structure more uniform. Combined with the thermal conductivity advantage of the aluminum alloy layer, it accelerates heat conduction and dissipation, reducing the rate of temperature rise. In summary, the synergistic effect of the compounds in the multi-component penetrant not only solves the core pain point of aluminum-iron interfacial bonding but also simultaneously optimizes key service performance such as wear resistance, heat resistance, and heat dissipation, demonstrating comprehensive application value superior to traditional technologies.

[0080] The present application has been described above with reference to preferred embodiments; however, these embodiments are merely exemplary and illustrative. Various substitutions and modifications can be made to the present application based on these embodiments, all of which fall within the protection scope of the present application.

Claims

1. A method for preparing an aluminum-cast iron layered composite brake disc, characterized in that, Includes the following steps: a) Select aluminum alloy and cast iron as raw materials, wherein the mass fraction of aluminum alloy is 30%-50% of the total mass, and the mass fraction of cast iron is 50%-70% of the total mass; b) Pre-treat the aluminum alloy and cast iron. Pretreatment and preparation stage: Femtosecond laser etching equipment is used to etch the contact surface between the cast iron layer and the aluminum alloy, and to process a composite microtexture of honeycomb micro-pits and annular micro-grooves. After etching, 400W, 20s argon plasma cleaning is used to remove residues and activate the surface activity of the cast iron. Simultaneously, a multi-component synergistic penetrant is prepared according to the mass ratio, specifically Ti 35%-40%, B 25%-30%, Ce-La composite rare earth 5%-8%, V-Nb composite 15%-20%, and Zr 5%-7%, and mixed and ground to a particle size of 30-50nm to ensure uniform dispersion. c) Filling and lamination stage: The multi-component synergistic penetrant is filled into the pits and grooves of the composite microtexture of the cast iron layer, and treated with 40kHz ultrasonic vibration for 5 minutes to eliminate powder agglomeration and achieve full coverage; then the cast iron layer filled with multi-component synergistic penetrant is laminated with the surface-cleaned aluminum alloy layer to ensure that the two layers are initially tightly bonded. d) Molding, cooling and testing stage: The laminated composite blank is placed into a hot press mold, and the hot pressing temperature and pressure are set. During the heat preservation process, the low melting point Al-B-Ti-Zr eutectic phase melts and the interface wetting angle is reduced to below 40°. Then, high temperature aging treatment is carried out to form a 180-280μm gradient functional diffusion layer. After high temperature aging, air cooling is used. After cooling is completed, the finished product is quality inspected.

2. The method for preparing an aluminum-cast iron layered composite brake disc according to claim 1, characterized in that: The aluminum alloy is an aluminum-silicon alloy with a silicon content of 9%-12% by mass and a thickness of 2.5mm to 4mm for the aluminum alloy layer.

3. The method for preparing an aluminum-cast iron layered composite brake disc according to claim 1, characterized in that: The cast iron is ductile iron or gray cast iron, and the thickness of the cast iron layer is 8mm to 12mm.

4. The method for preparing an aluminum-cast iron layered composite brake disc according to claim 1, characterized in that: The honeycomb-shaped micro-pits have a diameter of 60-100μm, a depth of 40-60μm, and a spacing of 180-220μm; the annular microgrooves have a width of 10-15μm, a depth of 15-20μm, and are radially distributed around the micro-pits.

5. The method for preparing an aluminum-cast iron layered composite brake disc according to claim 1, characterized in that: The amount of the multi-component synergistic penetrant added is 0.8%-1.2% of the total mass.

6. The method for preparing an aluminum-cast iron layered composite brake disc according to claim 1, characterized in that: The lamination speed is 1-3 mm / s.

7. The method for preparing an aluminum-cast iron layered composite brake disc according to claim 1, characterized in that: The hot pressing temperature is 300-450℃.

8. The method for preparing an aluminum-cast iron layered composite brake disc according to claim 1, characterized in that: The hot pressing pressure is 5-10 MPa.

9. The method for preparing an aluminum-cast iron layered composite brake disc according to claim 1, characterized in that: The high-temperature aging temperature is 450-450℃, and the time is 3 to 5 hours.

10. The method for preparing an aluminum-cast iron layered composite brake disc according to claim 1, characterized in that: The air cooling time is 2 to 6 hours.

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