High wear resistant particle reinforced aluminum matrix composite brake disc and insert casting method of manufacture

Abstract

This application belongs to the field of lightweight brake discs and their preparation, and discloses a high-wear-resistant particle-reinforced aluminum matrix composite brake disc and its inlay casting preparation method. The inlay casting preparation method includes: uniformly mixing reinforcing particles and matrix materials using an electromagnetic stirring process to obtain a semi-solid slurry; introducing the semi-solid slurry into a mold cavity and applying pressure for near-net-shape forming to obtain a finished insert as a high-wear-resistant braking layer, and imprinting a geometric interlocking structure on its inner surface; fixing the finished insert in a high-pressure die-casting mold, and filling the mold with molten metal at high speed through high-pressure die-casting. While forming the brake disc body and the closed liquid-cooled structure, the molten metal fills the gaps of the geometric interlocking structure on the inner surface of the high-wear-resistant braking layer. After solidification and cooling, the bimetallic solidification is achieved to obtain the brake disc. This application can solve the technical problems of existing composite brake discs where high-hardness composite materials are difficult to process and form, and where interlayer slippage easily occurs at the bimetallic interface.

Description

Technical Field

[0001] This application belongs to the field of lightweight brake discs and their preparation technology, and more specifically, relates to a high wear-resistant particle-reinforced aluminum matrix composite brake disc and its casting preparation method. Background Technology

[0002] Brake discs are the core friction element of automotive braking systems, and their performance directly affects driving safety. Traditional commercial and passenger vehicle brake discs are mostly made of cast iron. While this is cheaper, cast iron has a high density, which is detrimental to overall vehicle lightweighting. Under high-frequency or extreme braking conditions, cast iron brake discs lack sufficient surface wear resistance, easily leading to severe wear and thermal fatigue cracks, significantly impacting service life and driving safety. To balance lightweighting with high wear resistance, particle-reinforced aluminum matrix composites (such as SiC / Al composites) have been proposed for use in brake discs. Their high specific strength and good wear resistance make them ideal candidates to replace cast iron.

[0003] To circumvent the challenges of machining high-wear-resistant composite materials across the entire brake disc and control costs, bimetallic split brake discs have become a research hotspot. These discs involve manufacturing the high-wear-resistant composite brake layer and the aluminum alloy body separately before combining them. However, bimetallic split brake discs still face several technical bottlenecks in practical engineering applications: 1. Existing brake discs mostly adopt an open air-cooled design, relying on convective heat exchange with the air during disc rotation for heat dissipation. However, under extreme conditions such as continuous braking on long downhill slopes or high-frequency emergency braking, the air-cooling heat exchange efficiency easily reaches its physical limit, causing the brake disc temperature to rise sharply. This can easily lead to a "heat fade" phenomenon, where the friction coefficient drops drastically, resulting in a significant decrease in braking torque and seriously threatening driving safety. Existing open air-cooling solutions are limited by the physical nature of air's low specific heat capacity and limited convective heat transfer coefficient, making it difficult to fundamentally solve the heat dissipation bottleneck of bimetallic split brake discs under extreme conditions.

[0004] 2. In SiC particle-reinforced aluminum matrix composites, the hardness of the hard SiC particles is much higher than that of conventional tool materials, making traditional cutting extremely difficult, resulting in extremely high tool wear rates and low machining efficiency. Especially in processes such as machining closed cooling channels inside the brake disc and machining complex interlocking structures on the surface of the brake disc, the machinability of high-hardness composite materials severely restricts the engineering application and large-scale mass production of high-performance composite brake discs.

[0005] 3. Existing bimetallic brake discs often use welding methods such as friction stir welding and diffusion welding to join dissimilar metals. Because the joint interface is usually relatively smooth and lacks effective macroscopic physical anchoring design, the interface bonding mainly relies on weak metallurgical diffusion. Under the enormous alternating shear forces and thermal shocks generated by severe braking, the stress on the smooth interface is highly concentrated, making it prone to interface tearing and interlayer slippage, seriously affecting the reliability and safety of the brake disc. Furthermore, existing manufacturing processes usually require subsequent machining of the high-hardness composite layer after the bimetallic composite is completed to form the required surface structure, which further increases the manufacturing difficulty and cost. Summary of the Invention

[0006] In response to the deficiencies or improvement needs of existing technologies, this application provides a high wear-resistant particle-reinforced aluminum matrix composite brake disc and its inlay casting preparation method, aiming to solve the technical problems of the difficulty in processing and forming high hardness composite materials in existing composite brake discs, and the easy occurrence of interlayer slippage at the bimetallic interface.

[0007] The above-mentioned technical objectives of this application are mainly achieved through the following technical solutions.

[0008] On the one hand, this application provides a method for preparing a brake disc of high wear-resistant particle-reinforced aluminum matrix composite material by insert casting. The method includes the following steps: Step S10, using an electromagnetic stirring process to uniformly mix the reinforcing particles and the matrix material to obtain a semi-solid slurry. The forced convection generated by the electromagnetic stirring causes the hard reinforcing particles to be uniformly suspended in the semi-solid metal without settling, solving the technical problem that particles are prone to agglomeration and settling in a fully liquid state; Step S20, introducing the semi-solid slurry into a mold cavity and applying pressure to perform near-net-shape forming to obtain a finished insert as a high wear-resistant brake layer. The inner surface of the brake disc is integrally imprinted with a geometric interlocking structure during the near-net-shape forming process. This is achieved through a single, direct imprinting process utilizing the unique shape of the mold cavity, eliminating the need for subsequent machining of the high-hardness composite material. In step S30, the finished insert is fixed within a high-pressure die-casting mold. Molten metal is rapidly filled into the mold using high-pressure die-casting. Simultaneously, the molten metal fills the gaps in the geometric interlocking structure on the inner surface of the high-wear-resistant brake layer while forming the brake disc body and the closed liquid-cooling structure. After solidification and cooling, a bimetallic bond is achieved, resulting in the brake disc. The closed liquid-cooling structure is used in conjunction with an external liquid supply component to achieve liquid cooling of the brake disc. This three-step near-net-shape forming process achieves high-strength bimetallic bonding while simultaneously forming the brake disc body and the closed liquid-cooling structure, effectively overcoming the dual technical bottlenecks of difficult machining and weak interfacial bonding in traditional processes.

[0009] In a preferred embodiment of this application, in step S30, the inner surfaces of the two finished inserts prepared in step S20 are axially fixed relative to each other within the high-pressure die-casting mold. The two finished inserts and the high-pressure die-casting mold enclose a molding chamber for forming the brake disc body. A layer of the high-wear-resistant braking layer is solidified on each of the two sides of the formed brake disc. The axially relative arrangement of the two inserts ensures that both working surfaces of the brake disc have high wear resistance, while the enclosed molding chamber ensures the overall molding accuracy of the brake disc body.

[0010] In a preferred embodiment of this application, in step S10, the reinforcing particles are SiC particles, the matrix material is aluminum alloy, and the mass fraction of the SiC particles in the semi-solid slurry formed by mixing is 10wt.%-30wt.%; in step S30, the molten metal used to form the brake disc body is made of high-strength aluminum alloy. A SiC particle mass fraction in the range of 10wt.%-30wt.% can maintain good semi-solid rheological processing properties of the composite material while ensuring high wear resistance; using high-strength aluminum alloy to form the brake disc body ensures that the body has sufficient mechanical strength when subjected to braking loads.

[0011] In a preferred embodiment of this application, in step S20, chip removal lines are simultaneously imprinted on the outer surface of the high wear-resistant braking layer during near-net-shape molding. The chip removal lines and the geometric interlocking structure of the inner surface are imprinted in one molding process in the same molding operation, without any subsequent machining, which can drain water and remove chips in time during braking operation, keeping the friction interface clean.

[0012] In a preferred embodiment of this application, the geometric interlocking structure includes a protrusion extending outward from the inner surface of the high-wear-resistant braking layer, the protrusion having a draft angle of 5°-15°. When the draft angle is less than 5°, the toothed belt structure is prone to cracking during demolding of the high-wear-resistant braking layer; when the draft angle is greater than 15°, it weakens the bonding force between the high-wear-resistant braking layer and the brake disc body; the draft angle range of 5°-15° ensures smooth demolding while enabling the protrusion and the filled metal substrate to form an effective rigid mechanical barrier, cooperatively resisting the tangential braking torque.

[0013] In a preferred embodiment of this application, the geometric interlocking structure is a continuous involute trapezoidal toothed belt interlocking structure. The protrusion includes multiple protruding toothed belts extending outward in an involute shape. The multiple protruding toothed belts are spaced apart along the circumferential direction. The cross-section of each protruding toothed belt is trapezoidal, and its two sides are provided with the draft angles. The involute trapezoidal toothed belt can maximize resistance to the rotational tangential torque during braking, and the draft angles on both sides of the trapezoidal cross-section work together to form a strong physical blocking mechanism.

[0014] In a preferred embodiment of this application, the geometric interlocking structure is a discrete frustum-shaped staggered array interlocking structure. The protrusions include discrete protruding nodes covering the inner surface of the high wear-resistant braking layer. The protruding nodes are frustum-shaped and arranged in a circumferential staggered array, with adjacent frustum-shaped protruding nodes not overlapping on their radial extension lines. The discrete frustum-shaped staggered array eliminates the fragile linear slip surface, effectively dispersing braking shear stress in all directions. The volume shrinkage effect generated during the solidification of the high-pressure molten metal causes the aluminum substrate to tightly grip each protruding node, forming a thermal shrinkage encapsulation effect.

[0015] In a preferred embodiment of this application, the axial thickness of the brake disc is divided into three layers: upper, middle, and lower. The thickness of the high-wear-resistant brake layers on the upper and lower sides is 4mm-6mm, and the thickness of the brake disc body in the middle is 18mm-22mm. Preferably, the thickness of the high-wear-resistant brake layers on the upper and lower sides is 6mm, and the thickness of the brake disc body in the middle is 18mm. The thickness of the high-wear-resistant brake layers on the upper and lower sides, within the range of 4mm-6mm, can control the overall quality while ensuring sufficient wear resistance life; the thickness of the brake disc body in the middle, within the range of 18mm-22mm, provides sufficient axial space for the layout of the internal closed liquid-cooled architecture.

[0016] In a preferred embodiment of this application, the axial thickness of the brake disc body is divided into a secondary three-layer structure. The upper and lower sides, with a thickness of 2mm-6mm, are friction bearing layers, and the middle area, with a thickness of 10mm-14mm, is a fluid functional layer. The closed liquid cooling structure is formed within the fluid functional layer. The upper and lower friction bearing layers ensure high-strength heterogeneous interface composite and mechanical transmission between the brake disc body and the high-wear-resistant brake layer. The middle fluid functional layer is specifically used to lay out the closed liquid cooling structure, realizing the optimized design of axial functional partitioning, and enabling close-range strong convection heat exchange between the cooling medium and the high-heat friction area.

[0017] In a preferred embodiment of this application, the closed liquid cooling architecture is a separate water cooling architecture, which includes a heat absorption groove and a stationary water cooling jacket assembly. The heat absorption groove is an annular groove recessed radially inward from the outer periphery of the fluid functional layer, so that the cross-section of the brake disc body is I-shaped. The stationary water cooling jacket assembly is embedded non-contactly into the heat absorption groove, with a heat transfer gap between them. The heat transfer gap is filled with a high thermal conductivity medium. The stationary water cooling jacket assembly has a coolant circulation chamber inside, and is equipped with a coolant inlet and a coolant outlet. Preferably, a sealing ring is provided at the junction of the stationary water cooling jacket assembly and the groove opening of the heat absorption groove. In the separate water cooling architecture, the stationary water cooling jacket assembly is fixed to stationary components such as the axle, and non-contact heat transfer is achieved between it and the rotating brake disc through a high thermal conductivity medium, eliminating the risk of rotational seal leakage.

[0018] In a preferred embodiment of this application, the closed liquid cooling architecture is an integral water-cooling architecture, integrally formed within the fluid functional layer and rotating synchronously with the brake disc body. The integral water-cooling architecture includes an inlet annular groove and an outlet annular groove arranged axially side-by-side on the cylindrical surface of the central inner hole of the brake disc body, and an annular heat-absorbing cavity located inside the fluid functional layer. The outer rings of the inlet and outlet annular grooves are respectively provided with multiple radially arranged inlet and outlet spoke channels, both of which are connected to the annular heat-absorbing cavity. Preferably, the inlet and outlet spoke channels are staggered in the circumferential direction. The integral water-cooling architecture directly introduces coolant into the rotating disc body. Under the assistance of centrifugal force, the coolant flows outward through the inlet spoke channels and enters the annular heat-absorbing cavity for forced convection heat transfer. The staggered arrangement of the inlet and outlet spoke channels optimizes fluid dynamics performance and eliminates stress concentration.

[0019] On the other hand, this application also provides a high wear-resistant particle-reinforced aluminum matrix composite brake disc, which is manufactured using the above-mentioned casting method. It includes a high wear-resistant braking layer and a brake disc body axially bonded together. The inner surface of the high wear-resistant braking layer has an integrally formed raised geometric interlocking structure. The brake disc body is densely filled into the gaps of the geometric interlocking structure to form a mechanical interlock. A closed liquid cooling architecture is provided within the brake disc body to guide the circulating flow of liquid cooling medium to cool the brake disc. This brake disc functionally separates the high wear-resistant working surface from the high-strength load-bearing body through a three-layer architecture. The closed liquid cooling architecture achieves close-range, strong convective heat exchange between the cooling medium and the high-heat friction zone, eliminating the heat fade problem caused by insufficient open-air cooling efficiency.

[0020] In summary, compared with the prior art, the technical solutions conceived in this application mainly possess the following technical features and advantages: 1. The method for preparing a high wear-resistant particle-reinforced aluminum matrix composite brake disc described in this application employs an electromagnetic stirring process to prepare a semi-solid slurry of SiC particle-reinforced aluminum matrix composite material. Forced convection generated by electromagnetic stirring allows the hard SiC particles to be uniformly suspended in a semi-solid metal with high apparent viscosity. This overcomes the engineering pain points of traditional powder metallurgy methods, such as high cost, and mechanical stirring methods, which are prone to agglomeration at high particle content, leading to performance degradation. This method achieves uniform distribution of reinforcing particles in the aluminum matrix. Furthermore, a near-net-shape forming process using semi-solid rheological molding is employed, directly imprinting the geometric interlocking structure and chip removal markings with a mold. This eliminates the complex machining processes required for the high-hardness particle-reinforced aluminum matrix composite material. Simultaneously, the brake disc body and closed liquid-cooled structure are integrally formed through a liquid-solid high-pressure casting step, effectively controlling production costs and shortening the manufacturing cycle. This provides a practical and feasible technical path for the large-scale mass production of bimetallic brake discs.

[0021] 2. The high wear-resistant particle-reinforced aluminum matrix composite brake disc manufacturing method described in this application integrates the high wear-resistant braking layer with the brake disc body through liquid-solid high-pressure casting. The geometric interlocking structure on the inner surface of the high wear-resistant braking layer significantly increases the effective contact area of ​​the bimetallic interface. The protruding features with draft angles and the filled aluminum alloy body form a rigid mechanical barrier, which synergistically resists the huge tangential braking torque. With the help of the high pressure of the jet specific pressure of the high-pressure die casting, the aluminum alloy liquid metal penetrates deep into the micro-rough pores on the surface to form micro-riveting points. Utilizing the volume shrinkage characteristics of the liquid aluminum alloy during solidification, the aluminum alloy matrix tightly wraps each interlocking structure to produce a thermal shrinkage and tightening effect. The multi-dimensional synergistic mechanism of macro-geometric interlocking, micro-riveting and thermal shrinkage locking achieves a highly reliable and firm bond between dissimilar metals, effectively overcoming the technical bottleneck of interlayer slippage in traditional bimetallic brake discs.

[0022] 3. The brake disc formed by the casting preparation method of the high wear-resistant particle-reinforced aluminum matrix composite brake disc of this application has a closed liquid cooling structure in the inner brake disc body through axial partitioning. The closed liquid cooling completely replaces the open air cooling. By constructing a separate or integral liquid cooling structure in the middle fluid functional layer of the brake disc body, a close-range, large-area, and strong convective heat transfer between the high specific heat capacity cooling medium and the extremely high heat generation friction area is achieved. The heat transfer efficiency is greatly improved, which effectively suppresses the high temperature deformation and friction coefficient decay of the brake disc body under long downhill or high-frequency braking conditions, and avoids the heat decay phenomenon caused by insufficient heat dissipation efficiency of open air cooling. Attached Figure Description

[0023] Figure 1 This is a flowchart of the method for preparing the high wear-resistant particle-reinforced aluminum matrix composite brake disc described in this application; Figure 2 This is a schematic diagram of the high wear-resistant braking layer described in this application; Figure 3 This is a schematic diagram of another embodiment of the high wear-resistant braking layer described in this application; Figure 4 This is a schematic diagram of the structure of the brake disc described in this application; Figure 5 for Figure 4 A schematic cross-sectional view of the brake disc shown in the diagram; Figure 6 This is another structural schematic diagram of the brake disc described in this application; Figure 7 for Figure 6 The diagram shows a cross-sectional view of the brake disc.

[0024] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein: 10. High wear-resistant braking layer; 11. Raised toothed belt; 12. Raised node; 13. Chip removal marking; 20. Brake disc body; 21. Friction bearing layer; 22. Fluid function layer; 23. Separate water-cooling structure; 231. Heat absorption groove; 232. Static water-cooling jacket assembly; 233. Cooling medium inlet; 234. Cooling medium outlet; 235. Sealing ring; 24. Integral water-cooling structure; 241. Water inlet annular groove; 242. Water outlet annular groove; 243. Annular heat absorption cavity; 244. Water inlet spoke flow channel; 245. Water outlet spoke flow channel. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0026] Implementation Method 1: This application provides a method for the injection molding of a high wear-resistant particle-reinforced aluminum matrix composite brake disc, such as... Figure 1 As shown, the inlay casting preparation method includes the following steps: Step S10: Use electromagnetic stirring to uniformly mix the reinforcing particles and the matrix material to obtain a semi-solid slurry.

[0027] Step S20: The semi-solid slurry is introduced into the mold cavity and pressure is applied to perform near-net-shape forming to obtain the finished insert as the high wear-resistant braking layer 10. The inner surface of the high wear-resistant braking layer 10 is integrally imprinted with a geometric interlocking structure during the near-net-shape forming process.

[0028] Step S30: Fix the finished insert into the high-pressure die-casting mold, and fill the mold with molten metal at high speed through high-pressure die-casting. While forming the brake disc body 20 and the closed liquid cooling structure, the molten metal fills the gap of the geometric interlocking structure on the inner surface of the high wear-resistant brake layer 10. After solidification and cooling, the bimetallic solidification is achieved to obtain the brake disc. The closed liquid cooling structure is used to cooperate with the external liquid supply component to achieve liquid cooling of the brake disc.

[0029] The inlay casting preparation method described in this application employs a three-step near-net-shape forming process to prepare a bimetallic composite brake disc with a closed liquid-cooled structure. The three steps are: step S10 (electromagnetic stirring and mixing to form a blank), step S20 (molding near-net-shape forming), and step S30 (liquid-solid high-pressure inlay casting). The geometric interlocking structure is directly imprinted by a mold, avoiding machining of the high-hardness composite material. The liquid-solid high-pressure inlay casting forces the molten aluminum alloy to fill the gaps in the interlocking structure and simultaneously forms a closed liquid-cooled structure, achieving integrated manufacturing of high-strength bimetallic consolidation and efficient heat dissipation.

[0030] The following will describe in detail the specific process of each step of the inlay casting preparation method described in this application, with reference to the embodiments shown in the accompanying drawings.

[0031] Step S10 is the material mixing and blank preparation step, in which a semi-solid slurry is prepared using an electromagnetic stirring process.

[0032] First, the reinforcing particles and matrix material were selected and their mass ratio was confirmed. High-wear-resistant particles were used as the reinforcing particles, and aluminum alloy was used as the matrix material. The mass fraction of the high-wear-resistant particles in the semi-solid slurry formed by the mixture was 10wt.%-30wt.%. In this embodiment, A356 aluminum alloy was selected as the matrix material, and SiC hard reinforcing particles were added at a mass fraction of 20wt.%. To improve the wettability of the reinforcing particles with the molten aluminum, the SiC particles were preheated by baking at 400°C.

[0033] Then, the A356 aluminum alloy was placed in a graphite crucible and heated to melt in a pit-type resistance furnace at a temperature of 740℃ to 750℃. After the matrix alloy was completely melted, high-purity argon gas was introduced for degassing and refining for 10 minutes, followed by settling and slag removal. Subsequently, pretreated SiC particles were added to the aluminum alloy solution, and an electromagnetic stirrer was started and stirred continuously for 10 minutes, while the temperature was controlled to steadily decrease to the solid-liquid two-phase range of the matrix alloy, set at 580℃ to 600℃. Within this temperature range, the semi-solid slurry has a high apparent viscosity, which can effectively support the particles and keep them uniformly suspended without sedimentation, thus directly obtaining a semi-solid slurry of SiC particle-reinforced aluminum matrix composite material with uniform composition, without the need for further solidification into a solid billet.

[0034] Step S20 is a near-net-shape molding step, in which a finished insert is prepared as a wear-resistant braking layer using a semi-solid slurry.

[0035] The prepared semi-solid slurry is injected into a preheated mold using a quantitative casting system. The mold is then closed, and a high specific pressure of 50 MPa to 150 MPa is applied for 10 to 20 seconds. Under continuous high pressure, the semi-solid slurry exhibits excellent thixotropic rheological properties, smoothly and densely filling the mold cavity. The mold cavity is an annular chamber, forming a ring-shaped finished insert that serves as a high-wear-resistant braking layer 10. The axial thickness of the finished insert is designed to be 4 mm to 6 mm, ensuring sufficient wear resistance while controlling overall quality. In this embodiment, the thickness of the finished insert is designed to be 6 mm.

[0036] Leveraging the rheological filling capability of the semi-solid slurry and the special morphology of the molding cavity, a geometric interlocking structure with a draft angle is integrally imprinted on the inner surface of the finished insert. This interlocking structure can adopt a continuous involute trapezoidal toothed belt structure or a discrete frustum-shaped staggered array structure. After molding, the finished insert, serving as the high wear-resistant braking layer 10, has high density, achieving near-net-shape forming without machining. The inner surface of the finished insert and its geometric interlocking structure are used to combine with the subsequently molded brake disc body 20.

[0037] Specifically, such as Figure 2 As shown, in this embodiment, the inner surface of the high wear-resistant braking layer 10 is integrally embossed with a continuous involute trapezoidal toothed interlocking structure. The internal morphology of the molding cavity is designed to correspond to this structure, so that the finished insert can simultaneously form the corresponding interlocking structure during the near-net-shape molding process. The protrusions of this interlocking structure include multiple protruding toothed bands 11. Each protruding toothed band 11 is not arranged radially in a straight line, but extends outward in an involute curve, spaced apart along the circumferential direction, covering the annular inner surface of the high wear-resistant braking layer 10. The cross-section of the protruding toothed band 11 is designed as a trapezoidal structure, with draft angles on both sides. The draft angle ranges from 5° to 15°, and is preferably 10° in this embodiment. The width of the trapezoidal cross-section near the inner surface of the high wear-resistant braking layer 10 is greater than the width away from the inner surface, forming a shape that is wide at the bottom and narrow at the top to meet the requirements of the demolding process. The involute linear arrangement maximizes resistance to rotational tangential torque during braking. The draft angles on both sides of the trapezoidal cross-section and the filled aluminum alloy body form a rigid mechanical barrier, which together greatly increases the effective contact area of ​​the bimetallic interface, ensuring a high-strength bond between the high wear-resistant braking layer 10 and the brake disc body 20.

[0038] In another alternative embodiment, such as Figure 3As shown, in this embodiment, the inner surface of the high wear-resistant braking layer 10 is integrally imprinted with a discrete frustum-shaped staggered array interlocking structure. The internal morphology of the molding cavity is designed to correspond to this structure, so that the finished insert can simultaneously form the corresponding interlocking structure during the near-net-shape molding process. The protrusions of this interlocking structure include discrete protrusion nodes 12 covering the entire annular inner surface. Each protrusion node 12 is a frustum-shaped structure with a bottom cross-sectional area larger than the top cross-sectional area, possessing a large bottom and small top draft characteristic, which allows for smooth demolding during the molding process. The protrusion nodes 12 are arranged in a circumferential staggered array, and the protrusion nodes 12 on adjacent circumferential rings do not overlap on the radial extension line, exhibiting a staggered distribution. The staggered frustum array eliminates the linear fragile slip surface and can disperse braking shear stress in all directions; the high-pressure aluminum alloy molten metal fully wraps the sidewall of each frustum protrusion node 12, and generates a strong volume shrinkage effect during solidification, which makes the aluminum matrix tightly bind each protrusion node 12, forming a thermal shrinkage and tight-fitting effect, achieving excellent interface consolidation strength.

[0039] Better, such as Figure 4 As shown, in step S20 above, relying on the rheological filling ability of the semi-solid slurry and the special morphology of the molding cavity, the outer surface of the high wear-resistant braking layer 10 is simultaneously imprinted with chip removal lines 13 during near-net-shape molding. The number of chip removal lines 13 can be selected between 12 and 36, and they are directly imprinted by the mold cavity in one step without subsequent machining. This allows for timely drainage and chip removal during braking, keeping the friction interface clean. In this embodiment, the chip removal lines 13 are arc-shaped grooves that diffuse outward in the radial direction, and multiple arc-shaped grooves are spaced apart along the circumferential direction.

[0040] Step S30 is a liquid-solid high-pressure insert casting step, in which molten metal is rapidly filled into the die-casting mold and combined with the finished insert prepared in step S20 to form a bimetallic brake disc.

[0041] First, a metal material is selected as the brake disc body 20 and pre-treated. The molten metal used to form the brake disc body 20 is made of high-strength aluminum alloy material and heated to form an aluminum alloy molten metal, including but not limited to A380 and ADC12. In this embodiment, A380 aluminum alloy is selected as the material for the brake disc body 20, and it is heated to 700°C to 720°C to form an aluminum alloy molten metal.

[0042] Then, the two finished inserts prepared in step S20 are preheated to 250°C, and their inner surfaces are fixed axially opposite each other in a high-pressure die-casting mold. The two finished inserts and the high-pressure die-casting mold form a molding chamber for forming the brake disc body 20. After mold closing, A380 aluminum alloy molten metal is injected into the molding chamber at high speed and high pressure using a die-casting machine, with a pouring temperature of approximately 700°C to 720°C. The molten metal is filled into the mold at high speed through high-pressure die casting. After the aluminum alloy molten metal solidifies and cools, it forms the brake disc body 20, which is fixed to the two finished inserts. The brake disc body 20 has an overall annular structure, and its axial thickness is designed to be 18mm-22mm. In this embodiment, the thickness of the brake disc body 20 is designed to be 18mm.

[0043] The axial thickness of the brake disc formed in step S30 is divided into three layers: upper, middle, and lower. Figures 4 to 7 As shown, in this embodiment, the overall thickness of the brake disc is 30mm, the thickness of the high wear-resistant brake layers 10 on the upper and lower sides is 6mm, and the thickness of the brake disc body 20 in the middle is 18mm, forming a three-layer structure of "6mm-18mm-6mm". This ensures sufficient wear resistance and lifespan while controlling the overall weight, and also provides ample axial space for the layout of the internal closed liquid cooling structure.

[0044] During the filling process, the aluminum alloy molten metal is forcibly filled with all the gaps of the geometric interlocking structure on the inner surface of the insert. With the help of the high specific pressure of high pressure die casting, the molten metal penetrates deep into the micro-rough pores on the surface, forming micro-riveting points. The volume shrinkage generated when the aluminum alloy molten metal solidifies causes the brake disc body 20 to tightly wrap each interlocking structure on the finished insert, producing a thermal shrinkage and tightening effect. The multi-dimensional synergistic mechanism of macro-geometric interlocking, micro-riveting and thermal shrinkage locking together achieves the high-strength consolidation of the bimetallic metal.

[0045] Furthermore, such as Figure 5 and Figure 7 As shown, aluminum alloy molten metal is simultaneously and integrally formed into the brake disc body 20 and its internal closed liquid cooling structure under the guidance of the forming chamber. After solidification and cooling, a bimetallic high-strength solidified liquid-cooled brake disc is obtained. A high wear-resistant brake layer 10 is solidified on both sides of the formed brake disc.

[0046] Specifically, the axial thickness of the brake disc body 20 is further divided into a secondary three-layer structure. A 2mm-6mm thick aluminum alloy region is reserved on each side near the upper and lower high-wear-resistant brake layers 10 as a friction bearing layer 21, used to achieve a high-strength heterogeneous interface composite with the inner surface of the high-wear-resistant brake layer 10, undertaking the function of mechanical transmission. The middle 10mm-14mm thick aluminum alloy region serves as a fluid functional layer 22, specifically for arranging a closed liquid-cooling architecture. In this embodiment, the brake disc body 20 has a thickness of 18mm, with a thickness distribution of 4mm-10mm-4mm. The friction bearing layers 21 on the upper and lower sides are 4mm thick, and the middle fluid functional layer 22 is 10mm thick. It should be noted that the brake disc body 20 is integrally formed, without obvious layering or step-by-step molding. The three-layer structure is mainly designed to achieve a reasonable layout of the closed liquid-cooling architecture.

[0047] like Figure 4 and Figure 5 As shown, in this embodiment, it is a bimetallic brake disc with a separate water-cooling architecture 23. That is, the closed liquid cooling architecture inside the brake disc body 20 adopts a separate water-cooling architecture 23, which includes a heat absorption groove 231 and a stationary water-cooling jacket assembly 232. The heat absorption groove 231 is an annular groove that is radially recessed from the outer periphery of the fluid functional layer 22, so that the cross-section of the brake disc body 20 is I-shaped. This I-shaped structure reduces the overall weight while providing an embedded space for the external stationary water-cooling jacket assembly 232. The stationary water-cooling jacket assembly 232 is fixed to a stationary component such as an axle or steering knuckle by a bracket, and is independent of the brake disc body 20 and does not rotate with the brake disc.

[0048] It should be noted that the heat absorption groove 231 in the split water-cooled structure 23 is integrally formed with the brake disc body 20 in step S30, and the static water-cooled jacket assembly 232 needs to be prepared separately and used in conjunction with the heat absorption groove 231; in practice, the static water-cooled jacket assembly 232 and its connected liquid supply system are used as external liquid supply components.

[0049] The static water-cooled jacket assembly 232 is shaped to fit the heat absorption groove 231 and is embedded into the heat absorption groove 231 in an arc-shaped non-contact manner, with a uniform heat transfer gap between them. This heat transfer gap is filled with a heat-conducting medium with high thermal conductivity to achieve non-contact heat conduction between the static water-cooled jacket assembly 232 and the rotating brake disc body 20. The static water-cooled jacket assembly 232 has a closed coolant circulation chamber inside, and is equipped with a coolant inlet 233 and a coolant outlet 234, which are arranged far apart from each other in the circumferential direction. The coolant (water) continuously circulates in the coolant circulation chamber under the drive of an external water pump, so that the static water-cooled jacket assembly 232 always maintains a low temperature.

[0050] A sealing ring 235 is provided at the junction of the static water-cooled jacket assembly 232 and the groove of the heat absorption groove 231 to prevent the loss of the heat-conducting medium in the heat transfer gap. In operation, the braking heat generated by the high-wear-resistant braking layer 10 is first conducted to the brake disc body 20 via the friction bearing layer 21, and then transferred across the heat transfer gap to the outer shell of the static water-cooled jacket assembly 232 via the high thermal conductivity medium. Finally, it is rapidly carried away by the continuously flowing coolant inside the static water-cooled jacket assembly 232. Because the static water-cooled jacket assembly 232 is fixed to a stationary component, non-contact heat transfer between it and the rotating brake disc is achieved through the high thermal conductivity medium, eliminating the need for a rotary seal structure and avoiding the risk of rotary seal leakage.

[0051] In another alternative embodiment, such as Figure 6 and Figure 7 As shown, in this embodiment, it is a bimetallic brake disc with an integral water-cooling structure 24. That is, the closed liquid cooling structure inside the brake disc body 20 adopts an integral water-cooling structure 24, which is integrally formed in the fluid functional layer 22 and rotates synchronously with the brake disc body 20. It includes an inlet annular groove 241, an outlet annular groove 242, an annular heat absorption cavity 243, an inlet spoke flow channel 244, and an outlet spoke flow channel 245.

[0052] Specifically, on the cylindrical surface of the central inner hole of the brake disc body 20, strictly corresponding to the height range of the middle 10mm fluid functional layer 22, two annular grooves are integrally formed side by side along the axial direction. These are the upper water inlet annular groove 241 and the lower water outlet annular groove 242, respectively. The axial height of both annular grooves is 3mm, and an aluminum alloy partition is retained between the two annular grooves. This central inner hole is used to fit a stationary fluid distribution stator (the fluid distribution stator and its connected liquid supply system serve as an external liquid supply component), achieving radial dynamic and static sealing, allowing coolant to be injected into the rotating disc body from the stationary external pipeline. The annular heat-absorbing cavity 243 is integrally formed inside the fluid functional layer 22 and is located radially outside the two annular grooves. Multiple radially arranged water inlet spoke channels 244 and water outlet spoke channels 245 are respectively provided on the outer ring of the water inlet annular groove 241 and the water outlet annular groove 242. Both the water inlet spoke channels 244 and the water outlet spoke channels 245 are connected to the annular heat-absorbing cavity 243 located on the periphery. Both the inlet spoke channel 244 and the outlet spoke channel 245 adopt circular cross-section channels, preferably with a diameter of 3 mm, in order to eliminate stress concentration and optimize fluid dynamic performance.

[0053] Preferably, the inlet spoke flow channel 244 and the outlet spoke flow channel 245 are staggered at a fixed angle in the circumferential direction of the brake disc, that is, the adjacent inlet spoke flow channel 244 and outlet spoke flow channel 245 do not coincide in axial height and circumferential angle. This staggered arrangement can further optimize the hydrodynamic performance.

[0054] In operation, the coolant (water) is injected into the inlet annular groove 241 through the stationary stator, and flows unimpeded into each inlet spoke channel 244. Under the assistance of centrifugal force, it flows radially outward and enters the outer annular heat-absorbing cavity 243, where it undergoes forced convection heat exchange with the high-temperature disc. The high-temperature fluid, after absorbing heat, converges and flows back inward into the outlet spoke channel 245, finally exiting the disc through the outlet annular groove 242. Because the coolant is directly introduced into the interior of the rotating disc and comes into close contact with the high-heat friction area, the heat conduction path is short and the heat exchange efficiency is high, which can effectively suppress the high-temperature deformation of the brake disc body 20 and the decrease in the friction coefficient.

[0055] Implementation Method Two: This application also provides a high wear-resistant particle-reinforced aluminum matrix composite brake disc, which can be manufactured using the inlay casting preparation method described in Embodiment 1. Figures 4 to 7 As shown, the brake disc includes a high wear-resistant brake layer 10 and a brake disc body 20 axially joined together. The inner surface of the high wear-resistant brake layer 10 is integrally formed with a raised geometric interlocking structure. The brake disc body 20 is densely filled in the gap of the geometric interlocking structure to form a mechanical interlock. The brake disc body 20 is provided with a closed liquid cooling structure. The closed liquid cooling structure is used to guide the circulation of liquid cooling medium to cool the brake disc.

[0056] The brake disc described in this application uses a three-layer architecture to functionally partition the high wear-resistant working surface and the high-strength load-bearing body. The geometric interlocking structure is used to improve the bonding strength between the high wear-resistant brake layer 10 and the brake disc body 20. The closed liquid cooling architecture realizes close-range strong convection heat exchange between the cooling medium and the high-heat friction area, thereby avoiding the problem of heat attenuation caused by insufficient open air cooling heat dissipation efficiency.

[0057] like Figure 4 and Figure 5 As shown, in one embodiment, this application provides a bimetallic brake disc with a split water-cooling structure 23. The brake disc has a three-layer structure in axial cross-section, with prefabricated high-wear-resistant brake layers 10 on the top and bottom sides, and an aluminum alloy brake disc body 20 in the middle. The high-wear-resistant brake layer 10 directly bears the friction of the brake caliper; the side subjected to friction is the outer surface, and the side in contact with the brake disc body 20 is the inner surface.

[0058] The brake disc has an overall thickness of 30mm, with the upper and lower high-wear-resistant brake layers 10 each being 6mm thick, and the central brake disc body 20 being 18mm thick, forming a three-layer structure of "6mm-18mm-6mm". The high-wear-resistant brake layer 10 is made of SiC particle-reinforced A356 aluminum alloy, and the specific manufacturing process can adopt steps S10 and S20 as described in Embodiment 1; the brake disc body 20 is made of A380 aluminum alloy, and the specific manufacturing process can adopt step S30 as described in Embodiment 1. The high-wear-resistant brake layer 10 is combined with the brake disc body 20 through a geometric interlocking structure, such as... Figure 2 As shown, the geometric interlocking structure is a continuous involute trapezoidal toothed belt interlocking structure, which includes multiple raised toothed belts 11 disposed on the inner surface of the high wear-resistant braking layer 10. Each raised toothed belt 11 extends radially outward in an involute curve, and is spaced apart along the circumferential direction, covering the annular inner surface of the high wear-resistant braking layer 10; as shown Figure 3 As shown, the geometric interlocking structure is a discrete frustum-shaped staggered array interlocking structure, which includes discrete protruding nodes 12 covering the entire inner surface of the ring. Each protruding node 12 is arranged in a circumferential staggered array, and the protruding nodes 12 of adjacent rings do not overlap on the radial extension line and are staggered.

[0059] Preferably, the geometrically interlocking structure has a certain draft angle. For example... Figure 2 As shown, the cross-section of the raised toothed band 11 is designed as a trapezoidal structure, with draft angles on both sides, ranging from 5° to 15°; Figure 3 As shown, the raised nodes 12 are all frustum-shaped structures with a larger bottom cross-sectional area than the top cross-sectional area, which has the characteristics of a large bottom and a small top, and can be easily demolded in the molding process.

[0060] Furthermore, such as Figure 4 and Figure 5 As shown, the axial thickness of the brake disc body 20 is further divided into a secondary three-layer structure with a thickness distribution of 4mm-10mm-4mm. A 4mm thick aluminum alloy friction bearing layer 21 is retained on each side near the upper and lower high-wear-resistant brake layers 10 to achieve a high-strength heterogeneous interface composite with the inner surface of the high-wear-resistant brake layer 10, undertaking the function of mechanical transmission; the middle 10mm thick area is the fluid function layer 22, specifically used for arranging a closed liquid-cooled architecture.

[0061] In this embodiment, the fluid functional layer 22 is recessed radially inward to form an annular heat-absorbing groove 231, making the axial cross-section of the brake disc body 20 H-shaped. This H-shaped structure reduces the overall weight while providing embedded space for the external stationary water-cooling jacket assembly 232. The stationary water-cooling jacket assembly 232 is fixed to stationary components such as the axle or steering knuckle by a bracket, and is independent of the brake disc body 20, not rotating with the brake disc.

[0062] The static water-cooled jacket assembly 232 is shaped to fit the heat absorption groove 231 and is embedded into the heat absorption groove 231 in an arc-shaped non-contact manner, with a uniform heat transfer gap between them. This heat transfer gap is filled with a heat-conducting medium with high thermal conductivity to achieve non-contact heat conduction between the static water-cooled jacket assembly 232 and the rotating brake disc body 20. The static water-cooled jacket assembly 232 has a closed coolant circulation chamber inside, and is equipped with a coolant inlet 233 and a coolant outlet 234, which are arranged far apart from each other in the circumferential direction. The coolant (water) continuously circulates in the coolant circulation chamber under the drive of an external water pump, so that the static water-cooled jacket assembly 232 always maintains a low temperature.

[0063] A sealing ring 235 is provided at the junction of the static water-cooled jacket assembly 232 and the groove of the heat absorption groove 231 to prevent the loss of the heat-conducting medium in the heat transfer gap. In operation, the braking heat generated by the high-wear-resistant braking layer 10 is first conducted to the brake disc body 20 via the friction bearing layer 21, and then transferred across the heat transfer gap to the outer shell of the static water-cooled jacket assembly 232 via the high thermal conductivity medium. Finally, it is rapidly carried away by the continuously flowing coolant inside the static water-cooled jacket assembly 232. Because the static water-cooled jacket assembly 232 is fixed to a stationary component, non-contact heat transfer between it and the rotating brake disc is achieved through the high thermal conductivity medium, eliminating the need for a rotary seal structure and the risk of rotary seal leakage.

[0064] like Figure 6 and Figure 7 As shown, in another embodiment, this application provides a bimetallic brake disc with an integral water-cooled structure 24. The overall size and three-layer structure of the brake disc are the same as those in the aforementioned embodiment. The overall thickness of the brake disc is 30mm, the high wear-resistant brake layer 10 is 6mm, the brake disc body 20 is 18mm, and the internal axial space of the brake disc body 20 is also divided into a secondary three-layer structure of 4mm-10mm-4mm.

[0065] The main difference between this embodiment and the previous embodiment lies in the closed liquid cooling structure installed inside the brake disc body 20. Specifically, in this embodiment, on the cylindrical surface of the central inner hole of the brake disc body 20, strictly corresponding to the height range of the middle 10mm fluid functional layer 22, two annular grooves are formed side by side along the axial direction. These are the upper water inlet annular groove 241 and the lower water outlet annular groove 242, respectively. The axial height of both annular grooves is 3mm, and an aluminum alloy partition is maintained between the two annular grooves. This central inner hole is used to fit a stationary fluid distribution stator, achieving radial dynamic and static sealing, allowing coolant to be injected into the rotating disc body from a stationary external pipeline.

[0066] Multiple radially arranged inlet spoke channels 244 and outlet spoke channels 245 are respectively provided on the outer ring of the inlet annular groove 241 and the outlet annular groove 242. Both the inlet spoke channels 244 and the outlet spoke channels 245 are connected to the annular heat-absorbing cavity 243 located on the periphery. Both the inlet spoke channels 244 and the outlet spoke channels 245 adopt circular cross-section channels, preferably with a diameter of 3mm, to eliminate stress concentration and optimize hydrodynamic performance. The inlet spoke channels 244 and the outlet spoke channels 245 are staggered at a fixed angle in the circumferential direction of the brake disc, that is, adjacent inlet spoke channels 244 and outlet spoke channels 245 do not coincide in axial height and circumferential angle. This staggered arrangement can further optimize hydrodynamic performance.

[0067] In operation, the coolant is injected into the inlet annular groove 241 through the stationary stator, and flows unimpeded into each inlet spoke channel 244. Assisted by centrifugal force, it flows radially outward and enters the outer annular heat-absorbing cavity 243, where it undergoes forced convection heat exchange with the high-temperature disc. The heat-absorbing high-temperature fluid then converges and flows back inward into the outlet spoke channel 245, finally exiting the disc through the outlet annular groove 242. Because the coolant is directly introduced into the rotating disc and comes into close contact with the high-heat friction area, the heat conduction path is short, resulting in high heat exchange efficiency and effectively suppressing high-temperature deformation and friction coefficient attenuation of the brake disc body 20.

[0068] According to one embodiment of this application, such as Figure 4 and Figure 6 As shown, the outer surface of the high wear-resistant braking layer 10 inside the brake disc is provided with a plurality of chip removal lines 13. The number of chip removal lines 13 can be selected between 12 and 36. The chip removal lines 13 can be integrally formed during the preparation of the high wear-resistant braking layer 10 without subsequent machining. They can drain water and remove chips in time during braking operation, keeping the friction interface clean.

[0069] To further illustrate the characteristics and advantages of the brake disc as described in Embodiment 2, prepared using the casting method described in Embodiment 1 of this application, the performance of the brake disc prepared in this application was compared with that of several existing brake discs. The specific comparison test conditions and test results are as follows.

[0070] Two sets of embodiments and four sets of comparative examples are provided. Embodiments 1 and 2 are brake discs prepared using the method described in this application, the difference being the presence of an internal closed liquid cooling structure. Comparative Example 1 provides a traditional gray cast iron brake disc, a single-material brake disc formed using conventional casting. Comparative Example 2 provides a dual-material brake disc prepared in the same way as Embodiment 1, except that the wear-resistant layer insert in this comparative example lacks a geometric interlocking structure, and the brake disc body lacks an internal closed liquid cooling structure. Comparative Example 3 provides a dual-material brake disc prepared in the same way as Embodiment 1, except that the wear-resistant layer insert lacks a geometric interlocking structure. Comparative Example 4 provides a dual-material brake disc prepared in the same way as Embodiment 1, except that the brake disc body lacks an internal closed liquid cooling structure. Specific information for each embodiment and comparative example is shown in Table 1 below.

[0071] Table 1 Test Sample Number, Structural Material

[0072] To verify the merits of the above-mentioned brake discs, the brake discs were tested under three different simulated working conditions, and the performance of each group of brake discs in different aspects was tested respectively.

[0073] Operating Condition 1: Thermal Fading Bench Test.

[0074] On an inertial test bench, a simulated vehicle was set to brake from 100 km / h to 5 km / h under emergency braking conditions, with a braking deceleration of 0.4g (g=9.8). Fifteen braking cycles were performed, each lasting 45 seconds. Under these conditions, the highest temperature of the friction surface of each brake disc during a single braking cycle, the maximum radial temperature difference of the disc surface, the steady-state average coefficient of friction, and the coefficient of friction retention rate at high temperatures were obtained for each group of brake discs.

[0075] Operating Condition 2: Thermal fatigue bench test.

[0076] Heating phase: The control frame is continuously braked, causing the brake disc friction surface temperature to rise rapidly to 600℃; Cooling phase: The brakes are released, and forced air cooling is activated to lower the disc temperature to below 100℃; Number of cycles: 500 consecutive hot and cold cycles are performed. Under the above conditions, the number of thermal fatigue crack initiation and the thermal fatigue interface delamination rate of each group of brake discs are obtained.

[0077] Operating Condition 3: High-frequency durability wear test bench test.

[0078] The simulated vehicle speed was set to brake from 80 km / h to 30 km / h, with a braking deceleration of 0.3g (g=9.8), and 1000 braking cycles were performed continuously. Under the above conditions, the total wear amount of the wear layer on both sides of each brake disc was obtained.

[0079] The simulation test results under the above three working conditions are shown in Table 2 below.

[0080] Table 2. Bench test results of each group of brake disc samples

[0081] As can be seen from Tables 1 and 2, compared with the traditional single-material gray cast iron brake disc prepared in Comparative Example 1, the dual-material brake discs prepared in Examples 1 and 2 can effectively improve the comprehensive friction braking performance, heat fade resistance and wear life while achieving a significant reduction in total mass.

[0082] As can be seen from the data in Table 2 under operating condition 1, the high-temperature friction coefficient retention rate of the dual-material air-cooled brake discs prepared in Comparative Examples 2 and 4 is relatively low, and their resistance to thermal fading needs to be improved. This is because these two comparative examples only use air cooling, and under continuous braking conditions, the heat from the brake disc cannot dissipate quickly, leading to a decrease in the friction coefficient. In contrast, Examples 1 and 2, due to their built-in closed liquid cooling architecture and the separate and integrated water cooling architectures respectively, achieve a stable friction coefficient retention rate of over 90% at high temperatures.

[0083] As can be seen from the data in Working Condition 2 in Table 2, when the dual-material brake disc lacks a specific geometric interlocking structure, it cannot effectively resist high-frequency alternating thermal stress. Specifically, the brake discs prepared in Comparative Examples 2 and 3 exhibit higher thermal fatigue interface delamination rates. This is because the interface between the wear-resistant inserts and the brake disc body in these two sets of comparative examples lacks an interlocking structure, resulting in a relatively smooth interface. During intense alternating thermal cycles, due to the difference in linear expansion coefficients between the SiC particle-reinforced aluminum matrix composite wear-resistant layer and the pure aluminum alloy body, the smooth interface cannot provide effective mechanical bonding force to resist the enormous shear tensile stress caused by the difference in shrinkage rates, leading to fatigue separation of the interface. Although Comparative Example 4 uses an involute trapezoidal toothed belt interlocking structure, which limits interface delamination to some extent, its air-cooled heat dissipation has low heat dissipation efficiency and a short thermal fatigue crack initiation life. In contrast, the brake discs in Examples 1 and 2 synergistically couple the "closed liquid-cooled architecture" and the "geometric interlocking structure," exhibiting excellent structural stability.

[0084] As can be seen from the data in Table 2 under working condition 3, the total wear on both sides of the wear-resistant layer in Examples 1 and 2 is significantly lower than that in Comparative Example 1. The reason is that the extremely hard SiC particles uniformly distributed inside the composite material of Examples 1 and 2 form a micro-bearing skeleton, which effectively resists external cutting and ploughing effects. Combined with excellent cooling effect, this greatly improves the wear resistance of the brake disc.

[0085] In summary, compared with traditional gray cast iron brake discs and conventional dual-material brake discs, the brake discs formed using the preparation method of this application simultaneously form a "closed liquid cooling structure" and a "geometric interlocking structure" during the brake disc manufacturing process. This not only solves the problem of the difficulty in processing and forming high-hardness composite materials for composite brake discs, but also significantly improves the interfacial bonding strength and cooling effect of dual-material brake discs.

[0086] It should be understood that expressions such as "comprising" and "may include" as used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as "comprising" and / or "having" may be interpreted as indicating a specific characteristic, number, operation, constituent element, component, or combination thereof, but should not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0087] It should be understood that the terms “center,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “inner,” “outer,” “clockwise,” “counterclockwise,” “axial,” “radial,” and “circumferential” indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0088] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0089] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0090] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for fabricating a brake disc made of high wear-resistant particle-reinforced aluminum matrix composite material, characterized in that, include: Step S10: Use electromagnetic stirring to uniformly mix the reinforcing particles and the matrix material to obtain a semi-solid slurry; Step S20: The semi-solid slurry is introduced into the mold cavity and pressure is applied to perform near-net-shape forming to obtain a finished insert as a high wear-resistant braking layer (10). The inner surface of the high wear-resistant braking layer (10) is integrally imprinted with a geometric interlocking structure during the near-net-shape forming process. Step S30: Fix the finished insert in the high-pressure die-casting mold, and fill the mold with molten metal at high speed through high-pressure die-casting. While forming the brake disc body (20) and the closed liquid cooling structure, the molten metal fills the gap of the geometric interlocking structure on the inner surface of the high wear-resistant brake layer (10). After solidification and cooling, bimetallic solidification is achieved to obtain the brake disc. The closed liquid cooling structure is used to cooperate with the external liquid supply component to achieve liquid cooling of the brake disc.

2. The method for preparing a high wear-resistant particle-reinforced aluminum matrix composite brake disc by casting according to claim 1, characterized in that, In step S30 above, the inner surfaces of the two finished inserts prepared in step S20 are fixed axially relative to each other in the high pressure die-casting mold. The two finished inserts and the high pressure die-casting mold surround a forming chamber for forming the brake disc body (20). A layer of the high wear-resistant brake layer (10) is fixed on each of the two sides of the formed brake disc.

3. The method for preparing a high wear-resistant particle-reinforced aluminum matrix composite brake disc according to claim 1 or 2, characterized in that, In step S10 above, the reinforcing particles are SiC particles, the matrix material is aluminum alloy, and the mass fraction of the SiC particles in the semi-solid slurry formed by mixing is 10wt.%-30wt.%; and / or, in step S30 above, the molten metal used to form the brake disc body (20) is made of high-strength aluminum alloy.

4. The method for preparing a high wear-resistant particle-reinforced aluminum matrix composite brake disc by casting according to claim 1, characterized in that, In step S20 above, the outer surface of the high wear-resistant braking layer (10) is simultaneously imprinted with chip removal lines (13) during near-net-shape molding.

5. The method for preparing a high wear-resistant particle-reinforced aluminum matrix composite brake disc by casting according to claim 1, characterized in that, The geometric interlocking structure includes a protrusion protruding outward from the inner surface of the high wear-resistant braking layer (10), the protrusion having a draft angle of 5°-15°.

6. The method for preparing a high wear-resistant particle-reinforced aluminum matrix composite brake disc by casting according to claim 5, characterized in that, The geometric interlocking structure is a continuous involute trapezoidal toothed belt interlocking structure. The protrusion includes a plurality of protruding toothed belts (11) extending outward in an involute shape. The plurality of protruding toothed belts (11) are spaced apart along the circumferential direction. The cross-section of the protruding toothed belt (11) is trapezoidal and the draft angle is provided on both sides of the belt. Alternatively, the geometric interlocking structure is a discrete frustum-shaped staggered array interlocking structure, and the protrusion includes discrete protrusion nodes (12) covering the inner surface of the high wear-resistant braking layer (10). The protrusion nodes (12) are frustum-shaped and arranged in a circumferential staggered array. The protrusion nodes (12) on adjacent two sides do not overlap on the radial extension line.

7. The method for preparing a high wear-resistant particle-reinforced aluminum matrix composite brake disc by casting according to claim 2, characterized in that, The axial thickness of the brake disc is divided into three layers: upper, middle and lower. The thickness of the high wear-resistant brake layer (10) on the upper and lower sides is 4mm-6mm, and the thickness of the brake disc body (20) in the middle is 18mm-22mm.

8. The method for preparing a high wear-resistant particle-reinforced aluminum matrix composite brake disc according to any one of claims 1, 2, and 7, characterized in that, The axial thickness of the brake disc body (20) is divided into a secondary three-layer structure. The upper and lower sides are 2mm-6mm thick areas as friction bearing layers (21), and the middle area is 10mm-14mm thick areas as fluid functional layers (22). The closed liquid cooling structure is formed in the fluid functional layers (22).

9. The method for preparing a high wear-resistant particle-reinforced aluminum matrix composite brake disc by casting according to claim 8, characterized in that, The closed liquid cooling architecture is a separate water cooling architecture (23), which includes a heat absorption groove (231) and a static water cooling jacket assembly (232). The heat absorption groove (231) is an annular groove that is radially recessed from the outer periphery of the fluid functional layer (22) so that the cross-section of the brake disc body (20) is I-shaped. The static water cooling jacket assembly (232) is embedded non-contactly into the heat absorption groove (231), with a heat transfer gap between them. The heat transfer gap is filled with a high thermal conductivity medium. The static water cooling jacket assembly (232) has a coolant circulation chamber inside and is equipped with a coolant inlet (233) and a coolant outlet (234). A sealing ring (235) is provided at the junction of the static water cooling jacket assembly (232) and the groove of the heat absorption groove (231). Alternatively, the closed liquid cooling architecture is an integral water cooling architecture (24), integrally formed within the fluid functional layer (22) and rotating synchronously with the brake disc body (20). The integral water cooling architecture (24) includes an inlet annular groove (241) and an outlet annular groove (242) axially parallel to each other on the cylindrical surface of the central inner hole of the brake disc body (20), and an annular heat absorption cavity (243) located inside the fluid functional layer (22). The outer ring of the inlet annular groove (241) and the outer ring of the outlet annular groove (242) are respectively provided with multiple radially arranged inlet spoke channels (244) and outlet spoke channels (245). The inlet spoke channels (244) and the outlet spoke channels (245) are both connected to the annular heat absorption cavity (243). The inlet spoke channels (244) and the outlet spoke channels (245) are staggered in the circumferential direction.

10. A high wear-resistant particle-reinforced aluminum matrix composite brake disc, characterized in that, The high wear-resistant particle-reinforced aluminum matrix composite brake disc is manufactured using the inlay casting method of any one of claims 1 to 9. It includes a high wear-resistant brake layer (10) and a brake disc body (20) axially bonded together. The inner surface of the high wear-resistant brake layer (10) is integrally formed with a raised geometric interlocking structure. The brake disc body (20) is densely filled in the gap of the geometric interlocking structure to form a mechanical interlock. The brake disc body (20) is provided with a closed liquid cooling structure. The closed liquid cooling structure is used to guide the circulation of liquid cooling medium to cool the brake disc.

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