Method for producing layered aluminum matrix composite

Abstract

The application discloses a preparation method of layered aluminum matrix composite material, which realizes the layered combination of the aluminum matrix composite material through a friction stir welding technology, solves the stress problem caused by the connection of the aluminum matrix composite material and dissimilar metal materials under high-low temperature alternating use conditions, and thus improves the reliability of the layered connection and enhances the safety of the material in the service process. The layered aluminum matrix composite material presents gradient change in the thermal expansion coefficient from the top to the bottom structure, avoids the sudden change reduction of the thermal expansion coefficient from the composite layer to the matrix layer in the high-low temperature alternating application working condition, reduces the expansion or shrinkage stress when the composite layer is directly connected with the matrix layer, and significantly improves the interface bonding strength between the layers.

Description

Technical Field

[0001] This invention belongs to the field of high-strength, high-toughness, and lightweight structural component die-casting aluminum alloy technology, specifically relating to a method for preparing a layered aluminum-based composite material. Background Technology

[0002] Aluminum-based composites possess characteristics such as lightweight, high strength, high wear resistance, high modulus, high thermal conductivity, and low coefficient of thermal expansion, making them promising for applications in vehicle braking, electronic packaging, and other fields. These diverse applications place varied demands on the functionality of aluminum-based composites, with some requiring composite bonding between aluminum-based composites and aluminum alloys. However, when aluminum-based composites are directly bonded to aluminum alloys, the metallurgical bonding layer is typically thin, making them prone to failure under high shear forces. Furthermore, they are also susceptible to failure under alternating high and low temperature stresses. In practical applications, the size, aspect ratio, and content of ceramic particles in the aluminum-based composite also affect the material's fatigue resistance.

[0003] CN112413012A discloses a composite material brake disc. This patent uses a casting process to prepare aluminum-based composite material sheets and aluminum alloy blanks, and then achieves the connection between the two through friction stir processing. This gives it excellent wear resistance, thermal conductivity, and fatigue resistance. A serrated structure is formed between the composite layer and the matrix, but the bonding interface is mainly between the high-volume-fraction composite layer and the aluminum alloy matrix layer. Because an effective buffer is not formed between the composite layer and the matrix layer, the overall reliability and fatigue resistance of the component need to be further improved.

[0004] CN120038331A discloses a method for manufacturing a brake disc for rail transit vehicles. This method divides the brake disc structure into two layers. First, a first aluminum-based composite material with a ceramic particle mass fraction of 10-20% is filled into the mold cavity as a non-friction layer. This ensures structural strength while also providing good plasticity and thermal conductivity, facilitating the formation of heat dissipation fins. After smoothing, it undergoes pre-pressing. Subsequently, a second aluminum-based composite material with a ceramic particle mass fraction of 35-45% is filled onto its surface as a friction layer to improve the wear resistance and temperature resistance of the friction surface. After smoothing, the mold is closed and pressed. However, this method does not perform special treatment on the interface between the first and second aluminum-based composite material layers, resulting in a relatively flat interface. Under alternating temperature conditions, this interface is prone to failure due to thermal stress concentration. Furthermore, the first and second layers are not subjected to friction stirring treatment, leading to microstructure inhomogeneity. The composite material also exhibits anisotropy due to extrusion.

[0005] CN118242378A discloses an aluminum-silicon carbide composite brake disc and its preparation method. The brake disc is designed with three layers: an upper layer, a middle layer, and a lower layer. The upper and lower layers are made of silicon carbide (SiC) reinforced aluminum matrix composite material with a volume fraction of 70-75% and a thickness of 2-4 mm, respectively. The middle layer and the clutch part are made of aluminum-silicon carbide composite material with a SiC volume fraction of 45-58%. The method involves first preparing a preform containing 70-75% SiC for the upper and lower layers. An intermediate layer of SiC powder with a porosity of 42-55% is filled between the preforms. This intermediate layer is then immersed in molten aluminum alloy using a pressure infiltration process to allow the molten aluminum to penetrate, thereby achieving bonding between the preform and the powder layer. Because the bonding interface is formed by direct contact between the preform and the powder layer, and no interface treatment is performed between the upper surface layer and the middle layer, or between the lower surface layer and the middle layer, the bonding is abrupt and the bonding interface is relatively flat. This interface structure is prone to failure due to thermal stress fatigue under alternating temperature environments. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing layered aluminum-based composite materials. This method achieves layered bonding of aluminum-based composite materials through friction stir welding technology, solving the stress problem caused by the connection of aluminum-based composite materials with dissimilar metal materials under alternating high and low temperature conditions, improving the reliability of layered bonding, and enhancing the safety of materials during service.

[0007] The objective of this invention is achieved through the following technical solutions.

[0008] A method for preparing a layered aluminum-based composite material includes: spreading an intermediate layer powder with a thickness H on a matrix layer plate, placing a composite layer plate on the intermediate layer powder to obtain a plate to be treated, pressing the plate to be treated along its thickness direction until the intermediate layer powder forms a pre-treated intermediate layer with a thickness of 0.33*H~0.67*H to obtain a layered plate, and sequentially performing friction stir welding and T6 heat treatment on the layered plate to obtain a layered aluminum-based composite plate, wherein the intermediate layer powder is a mixture of ceramic powder and a first aluminum alloy powder, and the T6 heat treatment includes: solution treatment at 500~550℃ for 4~8 hours, water quenching, aging at 150~200℃ for 5~10 hours, followed by air cooling;

[0009] The lower surface of the composite layer material has an uneven structure, which includes multiple protrusions.

[0010] In the above technical solution, each protrusion structure is strip-shaped, and multiple protrusion structures are arranged horizontally.

[0011] In the above technical solution, the feed direction of the friction stir welding process is perpendicular to the length direction of the strip.

[0012] In the above technical solution, each protrusion is a horizontally arranged triangular prism. One face of the triangular prism is horizontally arranged, and the other two faces of the triangular prism serve as the lower surface of the composite layer material and are located below the horizontal face. All the protrusions are arranged in parallel along their length and are arranged in the transverse direction. Any two adjacent protrusions form a recess, and the protrusions and recesses form the concave-convex structure.

[0013] In the above technical solution, each protruding structure is a horizontally arranged column. All the protruding structures are arranged in parallel along their length direction and are spaced apart in the lateral direction. The bottom surface of the column is either planar or non-planar. Any two adjacent protruding structures form a recess. The protruding structures and the recesses form the concave-convex structure.

[0014] In the above technical solution, during friction stir welding, the stirring pin needs to pass through the composite layer plate and extend into the base layer plate to a depth of 2-3 mm.

[0015] In the above technical solution, the length of the stirring pin in the friction stir welding is 7~24mm.

[0016] In the above technical solution, the feed speed of the stirring head during friction stir welding is 200~350mm / min, the rotation speed of the stirring needle is 1000~1200r / min, and the pressing amount of the stirring head is 0.2~0.3mm.

[0017] In the above technical solution, the path of friction stir welding covers the entire upper surface of the composite layer plate.

[0018] In the above technical solution, the angle between the shoulder surface of the stirring head and the upper surface of the composite layer plate is 1°~5°.

[0019] In the above technical solution, the thickness of the composite layer plate is 4~15mm, and the thickness of the intermediate powder layer on the substrate plate is 6~10mm.

[0020] In the above technical solution, the method for preparing the intermediate layer powder includes: heat-treating ceramic powder at 1000~1200℃ for 1~5h under a protective atmosphere, and then mixing it evenly with the first aluminum alloy powder to obtain the intermediate layer powder, wherein, by volume, the ratio of ceramic powder to the first aluminum alloy powder is (1~6):9, and the ceramic powder is one or a mixture of silicon carbide, boron nitride, aluminum oxide, titanium oxide and titanium boride.

[0021] In the above technical solution, the aspect ratio of the ceramic powder in the intermediate layer powder is 1.31~1.45.

[0022] In the above technical solution, the first aluminum alloy powder, by mass percentage, comprises: 1-2 wt% copper (Cu), 0.8-1 wt% magnesium (Mg), 2-3 wt% silicon (Si), 0.1-0.5 wt% titanium (Ti), 0.05-0.2 wt% tin (Sn), 0.2-0.3 wt% Sc, 0.2-0.3 wt% Ce, and the balance aluminum (Al).

[0023] In the above technical solution, the pressing pressure is 80~120MPa.

[0024] In the above technical solution, the D50 of the ceramic powder is 5~15μm.

[0025] In the above technical solution, the method for preparing the substrate layer plate includes: melting ZL101A aluminum alloy material at 600~800℃, adding Al-Cu master alloy, Al-Sr alloy (as a modifier) ​​and refining agent to obtain a mixture, degassing and refining the mixture under argon atmosphere, and then casting to obtain a casting as the substrate layer plate. The mixture contains 2~3.5 wt% copper, 0.01~0.1 wt% Al-Sr alloy, 10~15 wt% Sr, and 0.5~2.5 wt% refining agent.

[0026] In the above technical solutions, casting is low-pressure casting, pressure casting, or gravity casting.

[0027] In the above technical solution, the refining agent includes sodium chloride, potassium chloride and sodium fluoroaluminate, wherein, by mass parts, the ratio of sodium chloride, potassium chloride and sodium fluoroaluminate is (30~40):(25~35):(10~20).

[0028] In the above technical solution, the degassing and refining time is 15~30 minutes.

[0029] In the above technical solution, the method for preparing the composite layer plate includes the following steps:

[0030] Step 1) The silicon carbide (SiC) powder is heat-treated under a protective atmosphere at a temperature of 1000~1200℃ for 1~5h. The heat-treated silicon carbide (SiC) powder is mixed evenly with the second aluminum alloy powder to obtain a first mixture. The first mixture is cold-pressed, degassed under vacuum, and then sintered at 450~600℃ for 1~10h. The mixture is then hot-pressed to obtain a blank. The ratio of silicon carbide powder to second aluminum alloy powder in the first mixture by volume is (1~6):9.

[0031] In step 1), the hot pressing pressure is 40~90MPa and the hot pressing time is 1~2h.

[0032] In step 1), the D50 of the silicon carbide powder is 20~50μm.

[0033] In step 1), the aspect ratio of the silicon carbide powder is 1.45 to 1.51.

[0034] In step 1), the heat-treated silicon carbide (SiC) powder and the second aluminum alloy powder are mixed evenly by ball milling. The ball milling speed is 30~60 rpm and the ball milling time is 1~2 hours.

[0035] In step 1), the cold pressing pressure is 50~300MPa and the cold pressing time is 1~30min.

[0036] In step 1), the vacuum degree of vacuum degassing is 10. -5 ~10 -2 Pa, vacuum degassing time is 1~4h.

[0037] Step 2) The blank obtained in Step 1) isothermally extruded at 400~500℃ to obtain a sheet material. The lower surface of the sheet material is milled or ground to form the concave-convex structure, thus obtaining a composite layer sheet material.

[0038] In step 2), the extrusion ratio of isothermal extrusion is (5~9):1.

[0039] In the above technical solution, the second aluminum alloy powder, by mass percentage, comprises: 1-2 wt% copper (Cu), 0.8-1 wt% magnesium (Mg), 2-3 wt% silicon (Si), 0.1-0.5 wt% titanium (Ti), 0.05-0.2 wt% tin (Sn), and the balance aluminum (Al).

[0040] In the above technical solution, the particle size of both the first aluminum alloy powder and the second aluminum alloy powder is 2~10μm.

[0041] In the above technical solution, the structure of the layered aluminum matrix composite material, from top to bottom, consists of a composite layer (formed from a composite layer sheet), an intermediate layer (formed from a pretreated intermediate layer), and a matrix layer. Within the temperature range of 0~300℃, the coefficient of thermal expansion of the composite layer is 12~16×10⁻⁶. -6 / K, the coefficient of thermal expansion of the intermediate layer is 15~20×10 -6 / K, the coefficient of thermal expansion of the substrate layer is 21~25×10 -6 / K.

[0042] In the above technical solution, the height of the concave-convex structure is 0.25~0.34 times the thickness of the intermediate layer.

[0043] In the above technical solution, the thickness of the composite layer after processing is 3-12mm, and the thickness of the intermediate layer is 2-6.5mm.

[0044] In the layered aluminum-based composite material of the present invention, the composite layer possesses excellent wear resistance and thermal conductivity, primarily undertaking the functions of wear resistance and thermal conductivity; the intermediate layer connects the composite layer and the matrix layer, serving as a transition; and the matrix layer mainly provides structural support and thermal conductivity. Compared with the prior art, the beneficial effects of the present invention are as follows:

[0045] 1. The preparation method of the present invention causes the internal components of the layered plate to flow laterally parallel to the shoulder surface of the stirring head under the rotational force of the stirring head of the friction stir welding. At the same time, due to the inclination angle between the shoulder surface of the stirring head and the upper surface of the composite plate, the interface between the composite layer and the intermediate layer, and between the intermediate layer and the matrix layer, has an irregular sawtooth structure that interlocks with each other and achieves a certain degree of fusion. This changes the original microstructure, eliminates defects such as pores in the original material, makes the material more compact, eliminates the material anisotropy caused by extrusion or casting, makes the grains of the material finer, increases the interlayer contact area, increases the stress resistance of the layered aluminum matrix composite material, improves the overall strength and elongation, and improves the fatigue resistance of the layered aluminum matrix composite material.

[0046] 2. Under the force of friction stir welding, the column of the composite layer plate set in this invention will be pushed along the direction of the stirring head feed. During the pushing process, the column will tilt and insert into the pre-treated intermediate layer, so that they can lock together and reduce the risk of failure.

[0047] 3. The thermal expansion coefficient of the layered aluminum matrix composite material of the present invention exhibits a gradient change from top to bottom. In high and low temperature alternating application conditions, it avoids the abrupt decrease of the thermal expansion coefficient from the composite layer to the matrix layer, reduces the expansion or contraction stress when the composite layer and the matrix layer are directly bonded, and significantly improves the interfacial bonding strength between the layers.

[0048] 4. The main function of the ceramic powder in the intermediate layer of this invention is to adjust the coefficient of thermal expansion and thermal conductivity. The ceramic powder particles in the intermediate layer are selected with different materials, sizes and roundness than those in the composite layer. The ceramic powder particles in the intermediate layer are selected with finer particle size and lower aspect ratio, which is beneficial to improving the stirring and friction processability of the material. The ceramic particles with finer particle size and lower aspect ratio are beneficial to improving its fatigue resistance, thereby improving the thermal conductivity and fatigue resistance of the layered aluminum matrix composite material.

[0049] 5. The first aluminum alloy powder of the present invention contains alloying elements such as Sc and Ce, which can disperse the precipitated phase, inhibit recrystallization, improve fatigue crack propagation resistance, enhance the fatigue strength of the intermediate layer, and prevent or slow down the propagation of defects in the composite layer or matrix layer to the interlayer, thereby improving the overall fatigue strength of the layered aluminum matrix composite material. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the composite layer plate of Embodiment 1 of the present invention, wherein a is a side view and b is a bottom view;

[0051] Figure 2 This is a side view of the plate material to be processed in Embodiment 1 of the present invention;

[0052] Figure 3 This is a schematic diagram of friction stir welding of the layered plates in Embodiment 1 of the present invention;

[0053] Figure 4 This is a schematic diagram of the layered aluminum-based composite material of Embodiment 1 of the present invention;

[0054] Figure 5 This is a schematic diagram of the preparation method (a) and the resulting layered aluminum matrix composite material in Example 2 of the present invention (b).

[0055] Figure 6 This describes the operation process of the preparation method in Example 3 of the present invention;

[0056] Figure 7 This describes the operation process of the preparation method in Comparative Example 1 of the present invention;

[0057] Figure 8 A schematic diagram of the structure of a layered aluminum matrix composite specimen for thermal fatigue testing;

[0058] Figure 9 The pressure curve for pressure casting.

[0059] Among them, 1: tooling, 2: intermediate layer powder, 3: matrix layer board, 4: composite layer board, 5: stirring head, 5-1: stirring needle, 6: matrix layer, 7: intermediate layer, 8: composite layer. Detailed Implementation

[0060] The technical solution of the present invention will be described in detail below with reference to the embodiments and accompanying drawings.

[0061] In the following embodiments, the first aluminum alloy powder comprises, by mass percentage: 1 wt% copper (Cu), 0.8 wt% magnesium (Mg), 2 wt% silicon (Si), 0.5 wt% titanium (Ti), 0.2 wt% tin (Sn), 0.25 wt% scandium (Sc), 0.25 wt% cerium (Ce), and the balance (95%) aluminum (Al).

[0062] The second aluminum alloy powder comprises, by mass percentage: 1 wt% copper (Cu), 0.8 wt% magnesium (Mg), 2 wt% silicon (Si), 0.5 wt% titanium (Ti), 0.2 wt% tin (Sn) and the balance (95.5%) aluminum (Al).

[0063] Example 1

[0064] A method for preparing a layered aluminum-based composite material, comprising: as follows Figure 2 As shown, a 10mm thick base layer plate 3 is fixed using tooling 1. A 9mm thick intermediate layer powder 2 is laid flat on the base layer plate 3. Then, a 10mm thick composite layer plate 4 (including the concave-convex structure) is placed on the intermediate layer powder to obtain the plate to be processed. The plate to be processed is pressed along its thickness direction under a pressure of 100MPa until the intermediate layer powder forms a 4mm thick pre-treated intermediate layer to obtain the layered plate. The layered plate is then subjected to friction stir welding and T6 heat treatment in sequence to obtain the layered aluminum-based composite plate. The intermediate layer powder is a mixture of silicon carbide powder and first aluminum alloy powder. The T6 heat treatment includes: solution treatment at 535℃ for 6 hours, water quenching, aging at 200℃ for 8 hours, and then air cooling.

[0065] The lower surface of the composite layer board has a textured surface, which includes multiple raised structures, such as... Figure 1 As shown, each protrusion is a horizontally arranged triangular prism. One face of the triangular prism is horizontal, and the other two faces of the triangular prism serve as the lower surface of the composite layer board and are located below the horizontal face. All the protrusions are arranged in parallel along their length and are arranged in the transverse direction. The cross section of the triangular prism is an isosceles triangle (the vertex of the isosceles triangle points downward and the height of the isosceles triangle is 1mm). Any two adjacent protrusions are in contact and form a recess between them. The protrusions and the recesses form a concave-convex structure.

[0066] The feed direction for friction stir welding is transverse (i.e., perpendicular to the length of the triangular prism) to improve the uniformity of the material at the joint, such as... Figure 3As shown, the stirring pin 5-1 used in the friction stir welding process has a length of 16mm. During the friction stir welding process, the stirring pin needs to pass through the composite layer plate and extend into the base layer plate to a depth of 2-3mm. The friction stir welding path covers the entire upper surface of the composite layer plate. The feed speed of the stirring head 5 is 250mm / min, the pressing amount of the stirring head is 0.2mm, the rotation speed of the stirring pin is 1200r / min, and the angle between the shoulder surface and the upper surface of the composite layer plate is 2.5°.

[0067] Under the action of the stirring needle, the concave-convex structure of the composite layer board deforms, and the original isosceles triangular prism tilts to one side, forming a hook-like shape (i.e., it is no longer an isosceles triangle), such as... Figure 4 As shown, this shape makes the interface between the composite layer and the intermediate layer more robust under alternating stress. The friction stir welding process further reduces the aspect ratio of the silicon carbide particles, improving fatigue resistance.

[0068] The method for preparing the intermediate layer powder includes: heat-treating silicon carbide (SiC) powder with a particle size D50 of 10 μm and an aspect ratio of 1.31 at 1100℃ for 2 h under an argon atmosphere. During the heat treatment, stirring is performed every 30 min to promote the formation of a uniform silicon oxide (SiO2) protective film on the surface of silicon carbide. The heat-treated silicon carbide powder is then ball-milled with a first aluminum alloy powder with a particle size of 2~10 μm at a speed of 45 rpm for 2 h to ensure uniform mixing and obtain the intermediate layer powder. The ratio of silicon carbide powder to first aluminum alloy powder by volume is 1:4.

[0069] The method for preparing the substrate layer plate includes: melting ZL101A aluminum alloy material (by mass percentage, ZL101A aluminum alloy material includes: 0.25% Cu, 7.2% Si, 0.35% Mg, 0.08% Ti, 0.18% Fe, and the balance aluminum) at 750℃, adding Al-Cu master alloy, Al-Sr alloy (as a modifier), and refining agent to obtain a mixture, degassing and refining the mixture under argon atmosphere for 20 minutes, and then performing pressure casting (the pressure curve of pressure casting is shown in Figure 1). Figure 9 As shown), the casting obtained is a base plate, wherein the mass fraction of copper in the mixture is 2wt%, the mass fraction of Al-Sr alloy in the mixture is 0.05wt%, and the amount of refining agent added in the mixture is 1wt%; the refining agent is a mixture of sodium chloride, potassium chloride and sodium fluoroaluminate, wherein, in the refining agent, by mass fraction, the ratio of sodium chloride, potassium chloride and sodium fluoroaluminate is 33:26:12, and the mass fraction of Sr in the Al-Sr alloy is 10wt%.

[0070] A method for preparing composite layer boards includes the following steps:

[0071] Step 1): Silicon carbide (SiC) powder with a particle size D50 of 25 μm and an aspect ratio of 1.51 was heat-treated under an argon atmosphere at 1100℃ for 2 hours. During the heat treatment, the powder was stirred every 30 minutes to promote the formation of a uniform silicon oxide (SiO2) protective film on the surface of the silicon carbide. The heat-treated silicon carbide powder was then ball-milled with a second aluminum alloy powder with a particle size of 2-10 μm at 45 rpm for 2 hours until homogeneous, resulting in a first mixture. This first mixture was then pressed at 200 MPa at room temperature for 10 minutes to form a final product. -3 Vacuum degassing was performed under a vacuum degree of Pa for 2 hours, followed by sintering at 550°C for 2 hours, and hot pressing at 550°C (the hot pressing pressure was 75 MPa, and the hot pressing time was 1.5 hours) to obtain a blank. In this blank, the ratio of silicon carbide powder to aluminum alloy powder in the first mixture was 3:7 by volume.

[0072] Step 2) The blank obtained in Step 1) isothermally extruded at 450°C with an extrusion ratio of 7:1 to obtain a sheet. The lower surface of the sheet is milled or ground to form the aforementioned uneven structure, thus obtaining a composite layer sheet. The uneven structure can increase the contact area between the composite layer and the intermediate layer, and at the same time optimize the distribution gradient of silicon carbide powder between the two layers, thereby mitigating the abrupt change in material properties at the interface.

[0073] like Figure 4 As shown, the layered aluminum matrix composite material prepared in Example 1 consists of three layers, from top to bottom: a composite layer 8 (formed from composite layer sheet 4), an intermediate layer 7 (formed from intermediate layer powder 2), and a matrix layer 6 (formed from matrix layer sheet 3). The thickness of the composite layer is 9.8±0.5 mm, the thickness of the intermediate layer is 4±0.5 mm, and the thickness of the matrix layer is 10±0.5 mm. The composite layer and the intermediate layer are interlocked and fused to a certain extent through a serrated structure. The volume fraction of the reinforcing phase (silicon carbide powder) varies gradient between the layers, which can effectively improve the interfacial bonding strength between the layers. The thickness and structure of the matrix layer can be designed according to specific application requirements, mainly playing a role in structural support and thermal conductivity.

[0074] When the composite layer is responsible for wear resistance, it requires coarser silicon carbide powder, while the intermediate layer requires strength and fatigue resistance. Therefore, when setting the particle size, coarser silicon carbide (SiC) powder is selected to prepare the composite layer, which can allow some sharp corners. The ceramic powder in the intermediate layer is selected with fine particles and must have sufficient roundness to ensure good strength and fatigue resistance.

[0075] According to the standard "Determination of Thermal Expansion Characteristic Parameters of Metallic Materials" (GB / T 4339-2008), the coefficient of thermal expansion of the composite layer is 15.28 × 10⁻⁶ within the range of 0~300℃. -6 / K, the coefficient of thermal expansion of the intermediate layer is 19.31×10 -6 / K, the coefficient of thermal expansion of the substrate layer is 24.12×10 -6 / K, the coefficient of thermal expansion of the intermediate layer is between that of the composite layer and the matrix layer, and the overall distribution is gradient. This can effectively alleviate the thermal stress caused by the difference in thermal expansion between the layers, thereby improving the structural stability and service life of the material under alternating high and low temperature conditions.

[0076] The mechanical properties of the layered aluminum matrix composite material in Example 1 were determined according to GB / T 228.1-2021 Metallic Materials - Tensile Testing - Part 1: Room Temperature Test Method: The average grain size of the composite layer was 1-10 μm, with a density of 99.6%, a tensile strength of 286 MPa, and an elongation after fracture of 4.3%. The average grain size of the intermediate layer was 1-5 μm, with a density of 99.8%, a tensile strength of 368 MPa, and an elongation after fracture of 7.5%. The average grain size of the matrix layer was 60-80 μm, with a density of 99.1%, a tensile strength of 245 MPa, and an elongation after fracture of 2.2%. The intermediate layer exhibited a high elongation after fracture and good plastic deformation capacity. Under alternating high and low temperature loads, it can act as a buffer layer between the composite layer and the matrix layer, significantly improving the overall fatigue resistance of the material.

[0077] According to the "HB 6660-2011 Test Method for Thermal Fatigue of Metal Sheets", the layered aluminum matrix composite material of Example 1 (the layered aluminum matrix composite material is a plate-shaped specimen of 50mm×20mm×2mm, with a V-shaped notch of 1.5mm depth on one side of the specimen, the V-shaped notch being in the middle layer, such as...) Figure 8 (As shown) A thermal fatigue sample was taken along the vertical plane of the bonding surface, with a V-shaped notch in the middle layer. The thermal fatigue properties were tested after 500 cycles at 0~350℃, and no cracks were found.

[0078] Example 2

[0079] A method for preparing a layered aluminum-based composite material is basically the same as in Example 1, except that the triangular prisms in the concave-convex structure are replaced with "prisms". All the protruding structures are arranged parallel in their length direction and spaced laterally, and the bottom surface of the prisms is as shown in the figure. Figure 5 As shown in Figure a, any two adjacent protrusions form a depression, and the protrusions and depressions together form the convex-concave structure. The layered aluminum-based composite material obtained by the preparation method of this embodiment is as follows: Figure 5 As shown in b.

[0080] The mechanical properties of the layered aluminum matrix composite material in Example 2 were determined according to GB / T 228.1-2021 Metallic Materials - Tensile Testing - Part 1: Room Temperature Test Method: The average grain size of the composite layer was 1-10 μm, with a density of 99.6%, a tensile strength of 281 MPa, and an elongation after fracture of 4.2%. The average grain size of the intermediate layer was 1-5 μm, with a density of 99.7%, a tensile strength of 361 MPa, and an elongation after fracture of 8.0%. The average grain size of the matrix layer was 60-80 μm, with a density of 99.2%, a tensile strength of 238 MPa, and an elongation after fracture of 2.3%. According to the standard GB / T 4339-2008 "Determination of Thermal Expansion Characteristic Parameters of Metallic Materials", the coefficient of thermal expansion of the composite layer was 15.43 × 10⁻⁶ °C within the range of 0-300 °C. -6 / K, the coefficient of thermal expansion of the intermediate layer is 19.15×10 -6 / K, the coefficient of thermal expansion of the substrate layer is 24.86×10 -6 / K.

[0081] According to the "HB 6660-2011 Test Method for Thermal Fatigue of Metal Sheets", thermal fatigue samples were taken from the layered aluminum matrix composite material of Example 2 along the vertical plane of the bonding surface. The V-shaped notch was made in the middle layer (the layered aluminum matrix composite material was a plate-shaped sample of 50mm×20mm×2mm, with a V-shaped notch with a depth of 1.5mm on one side of the sample, and the V-shaped notch was made in the middle layer). The thermal fatigue properties were tested after 500 cycles at 0~350℃, and no cracks were found.

[0082] Example 3

[0083] A method for preparing a layered aluminum-based composite material is basically the same as in Example 1, except that: the upper surface of the matrix layer also forms a concave-convex structure, and the concave-convex structure on the upper surface of the matrix layer matches the concave-convex structure on the lower surface of the composite layer. For example... Figure 6 As shown.

[0084] The mechanical properties of the layered aluminum matrix composite material obtained in Example 3 were tested according to GB / T 228.1-2021 Metallic Materials - Tensile Testing - Part 1: Room Temperature Test Method: The average grain size of the composite layer was 1-10 μm, the density was 99.5%, the tensile strength of the composite layer was 268 MPa, and the elongation after fracture was 3.8%; the average grain size of the intermediate layer was 1-5 μm, the density was 99.8%, the tensile strength of the intermediate layer was 365 MPa, and the elongation after fracture was 7.3%; the average grain size of the matrix layer was 60-80 μm, the density was 99.1%, the tensile strength of the matrix layer was 232 MPa, and the elongation after fracture was 2.5%.

[0085] According to the standard "Determination of Thermal Expansion Characteristic Parameters of Metallic Materials" (GB / T 4339-2008), the coefficient of thermal expansion of the composite layer is 15.64 × 10⁻⁶ within the range of 0~300℃. -6 / K, the coefficient of thermal expansion of the intermediate layer is 19.78×10 -6 / K, the coefficient of thermal expansion of the substrate layer is 24.12×10 -6 / K.

[0086] According to the "HB 6660-2011 Test Method for Thermal Fatigue of Metal Sheets", thermal fatigue samples were taken from the layered aluminum matrix composite material of Example 3 along the vertical plane of the bonding surface, with a V-shaped notch in the middle layer. The thermal fatigue properties were tested after 500 cycles at 0~350℃, and no cracks were found.

[0087] Comparative Example 1 (without an intermediate layer)

[0088] A method for preparing a layered aluminum-based composite material is disclosed, which is the composite material brake disc in patent publication number CN112413012A, and is basically the same as Example 1, except that: no intermediate powder layer is set, and the lower surface of the composite layer plate has a flat structure. The preparation of the layered aluminum-based composite material is as follows: Figure 7 As shown.

[0089] The mechanical properties of the layered aluminum matrix composite material of Comparative Example 1 were determined according to GB / T 228.1-2021 Metallic materials, tensile testing—Part 1: Test method at room temperature: The average grain size of the composite layer was 1~10μm, the density was 99.5%, the tensile strength ranged from 279MPa, and the elongation after fracture was 3.8%; the average grain size of the matrix layer was 60~80μm, the density was 99.3%, the tensile strength was 246MPa, and the elongation after fracture was 2.4%.

[0090] According to the standard "Determination of Thermal Expansion Characteristic Parameters of Metallic Materials" (GB / T 4339-2008), the coefficient of thermal expansion of the composite layer is 15.86 × 10⁻⁶ within the temperature range of 0~300℃. -6 / K, the coefficient of thermal expansion of the substrate layer is 23.95×10 -6 / K.

[0091] According to the "HB 6660-2011 Test Method for Thermal Fatigue of Metal Sheets", thermal fatigue samples were taken from the vertical plane of the bonding surface of the layered aluminum matrix composite material of Comparative Example 1. The V-shaped notch was opened at the bonding point between the composite layer and the matrix layer. The thermal fatigue properties were tested by 500 cycles at 0~350℃, and the crack length was measured to be 85μm.

[0092] Comparative Example 2 (no intermediate layer, no stirring)

[0093] A layered aluminum-based composite material, which is the brake disc for rail transit vehicles of Example 1 in Publication No. CN120038331A.

[0094] The mechanical properties of the layered aluminum matrix composite material of Comparative Example 2 were determined according to GB / T 228.1-2021 Metallic Materials - Tensile Testing - Part 1: Test Method at Room Temperature: The average grain size of the second aluminum matrix composite layer (formed from the second aluminum matrix composite material) was 20-30 μm, the density was 99.0%, the tensile strength was 276 MPa, and the elongation after fracture was 2%; the average grain size of the first aluminum matrix composite layer (formed from the first aluminum matrix composite material) was 20-30 μm, the density was 99.1%, the tensile strength was 289 MPa, and the elongation after fracture was 4%.

[0095] According to the standard "Determination of Thermal Expansion Characteristic Parameters of Metallic Materials" (GB / T 4339-2008), the coefficient of thermal expansion of the second aluminum-based composite layer is 14.86 × 10⁻⁶ within the temperature range of 0~300℃. -6 / K, the coefficient of thermal expansion of the first aluminum-based composite layer is 19.58×10. -6 / K.

[0096] According to the "HB 6660-2011 Test Method for Thermal Fatigue of Metal Sheets", thermal fatigue samples were taken from the vertical plane of the bonding surface of the layered aluminum matrix composite material of Comparative Example 2. The V-shaped notch was opened at the bonding point between the first aluminum matrix composite layer and the second aluminum matrix composite layer. The thermal fatigue properties were tested by 500 cycles at 0~350℃, and the crack length was measured to be 1085μm.

[0097] Comparative Example 3

[0098] A layered aluminum-based composite material, which is the multilayer aluminum silicon carbide brake disc of Example 1 in CN118242378A.

[0099] The mechanical properties of the layered aluminum matrix composite material of Comparative Example 3 were determined according to GB / T 228.1-2021 Metallic materials, tensile testing—Part 1: Test methods at room temperature: The average grain size of the upper layer was 20-30 μm, the density was 99.6%, the tensile strength was 225 MPa, and the elongation after fracture was 0.5%; the average grain size of the middle layer was 20-30 μm, the density was 99.8%, the tensile strength was 248 MPa, and the elongation after fracture was 1%; the average grain size of the lower layer was 20-30 μm, the density was 99.1%, the tensile strength was 225 MPa, and the elongation after fracture was 0.5%.

[0100] According to the standard "Determination of Thermal Expansion Characteristic Parameters of Metallic Materials" (GB / T 4339-2008), the coefficient of thermal expansion of the upper surface layer is 8.9 × 10⁻⁶ within the range of 0~300℃.-6 / K, the coefficient of thermal expansion of the intermediate layer is 12.5×10 -6 / K, the coefficient of thermal expansion of the lower surface layer is 8.9×10 -6 / K.

[0101] According to the "HB 6660-2011 Test Method for Thermal Fatigue of Metal Sheets", thermal fatigue samples were taken from the vertical plane of the bonding surface of the layered aluminum matrix composite material of Comparative Example 3. The V-shaped notch was opened at the bonding point between the upper and middle layers. The thermal fatigue properties were tested by 500 cycles at 0~350℃, and the crack length was measured to be 1435μm.

[0102] Comparative Example 4

[0103] A method for preparing a layered aluminum-based composite material is basically the same as that in Example 1, except that: in the intermediate layer powder, the aluminum alloy powder in the intermediate layer powder is a second aluminum alloy powder.

[0104] The mechanical properties of the layered aluminum matrix composite material of Comparative Example 4 were determined according to GB / T 228.1-2021 Metallic Materials - Tensile Testing - Part 1: Test Method at Room Temperature: The average grain size of the composite layer was 1-10 μm, the density was 99.5%, the tensile strength was 281 MPa, and the elongation after fracture was 4.1%; the average grain size of the intermediate layer was 1-5 μm, the density was 99.7%, the tensile strength was 345 MPa, and the elongation after fracture was 6.5%; the average grain size of the matrix layer was 60-80 μm, the density was 99.1%, the tensile strength was 243 MPa, and the elongation after fracture was 2.4%.

[0105] According to the standard "Determination of Thermal Expansion Characteristic Parameters of Metallic Materials" (GB / T 4339-2008), the coefficient of thermal expansion of the composite layer is 15.16 × 10⁻⁶ within the range of 0~300℃. -6 / K, the coefficient of thermal expansion of the intermediate layer is 19.25×10 -6 / K, the coefficient of thermal expansion of the substrate layer is 23.25×10 -6 / K.

[0106] According to the "HB 6660-2011 Test Method for Thermal Fatigue of Metal Sheets", the layered aluminum matrix composite material of Comparative Example 4 (the layered aluminum matrix composite material is a plate-shaped specimen of 50mm×20mm×2mm, with a V-shaped notch of 1.5mm depth on one side of the specimen, the V-shaped notch is made in the middle layer, such as...) Figure 8 (As shown) A thermal fatigue sample was taken along the vertical plane of the bonding surface, with a V-shaped notch in the middle layer. The thermal fatigue properties were tested after 500 cycles at 0~350℃, and the crack length was 125μm.

[0107] Comparative Example 5

[0108] A method for preparing a layered aluminum-based composite material is basically the same as that in Example 1, except that the D50 and aspect ratio of the silicon carbide (SiC) powder in the intermediate layer powder are different. In this comparative example, the D50 of the silicon carbide powder in the intermediate layer powder is 100 μm, and the aspect ratio is 1.51.

[0109] The mechanical properties of the layered aluminum matrix composite material of Comparative Example 5 were determined according to GB / T 228.1-2021 Metallic Materials - Tensile Testing - Part 1: Test Method at Room Temperature: The average grain size of the composite layer was 1-10 μm, the density was 99.6%, the tensile strength was 290 MPa, and the elongation after fracture was 4.1%; the average grain size of the intermediate layer was also 1-5 μm, the density was 99.6%, the tensile strength was 278 MPa, and the elongation after fracture was 3.2%; the average grain size of the matrix layer was 60-80 μm, the density was 99.2%, the tensile strength was 239 MPa, and the elongation after fracture was 2.4%.

[0110] According to the standard "Determination of Thermal Expansion Characteristic Parameters of Metallic Materials" (GB / T 4339-2008), the coefficient of thermal expansion of the composite layer is 15.23 × 10⁻⁶ within the range of 0~300℃. -6 / K, the coefficient of thermal expansion of the intermediate layer is 18.63×10 -6 / K, the coefficient of thermal expansion of the substrate layer is 23.96×10 -6 / K.

[0111] According to the "HB 6660-2011 Test Method for Thermal Fatigue of Metal Sheets", the layered aluminum matrix composite material of Comparative Example 5 (the layered aluminum matrix composite material is a plate-shaped specimen of 50mm×20mm×2mm, with a V-shaped notch of 1.5mm depth on one side of the specimen, the V-shaped notch being located in the middle layer, such as...) Figure 8 (As shown) A thermal fatigue sample was taken along the vertical plane of the bonding surface, with a V-shaped notch in the middle layer. The thermal fatigue properties were tested after 500 cycles at 0~350℃, and the crack length was 430μm.

[0112] Comparative Example 6

[0113] A method for preparing a layered aluminum-based composite material is basically the same as that in Example 1, except that: in this comparative example, the D50 of the silicon carbide powder in the intermediate layer powder is 25 μm, the aspect ratio is 1.51, and the ratio of silicon carbide powder to first aluminum alloy powder in the intermediate layer powder is 5:5 by volume.

[0114] The mechanical properties of the layered aluminum matrix composite material of Comparative Example 6 were determined according to GB / T 228.1-2021 Metallic Materials - Tensile Testing - Part 1: Test Method at Room Temperature: The average grain size of the composite layer was 1-10 μm, the density was 99.5%, the tensile strength was 290 MPa, and the elongation after fracture was 4.1%; the average grain size of the intermediate layer was also 1-5 μm, the density was 99.3%, the tensile strength was 275 MPa, and the elongation after fracture was 1.5%; the average grain size of the matrix layer was 60-80 μm, the density was 99.3%, the tensile strength was 239 MPa, and the elongation after fracture was 2.7%.

[0115] According to the standard "Determination of Thermal Expansion Characteristic Parameters of Metallic Materials" (GB / T 4339-2008), the coefficient of thermal expansion of the composite layer is 15.38 × 10⁻⁶ within the range of 0~300℃. -6 / K, the coefficient of thermal expansion of the intermediate layer is 13.61×10 -6 / K, the coefficient of thermal expansion of the substrate layer is 23.92×10 -6 / K.

[0116] According to the "HB 6660-2011 Test Method for Thermal Fatigue of Metal Sheets", the layered aluminum matrix composite material of Comparative Example 6 (the layered aluminum matrix composite material is a plate-shaped specimen of 50mm×20mm×2mm, with a V-shaped notch of 1.5mm depth on one side of the specimen, the V-shaped notch being located in the middle layer, such as...) Figure 8 (As shown) A thermal fatigue sample was taken along the vertical plane of the bonding surface, with a V-shaped notch in the middle layer. The thermal fatigue properties were tested after 500 cycles at 0~350℃, and the crack length was 380μm.

[0117] The present invention has been described above by way of example. It should be noted that any simple modifications, alterations or other equivalent substitutions that can be made by those skilled in the art without creative effort without departing from the core of the present invention fall within the protection scope of the present invention.

Claims

1. A method for preparing a layered aluminum-based composite material, characterized in that, include: The intermediate layer powder is spread evenly on the base layer plate with a thickness H, and then the composite layer plate is placed on the intermediate layer powder to obtain the plate to be treated. The plate to be treated is pressed along its thickness direction until the intermediate layer powder forms a pre-treated intermediate layer with a thickness of 0.33*H~0.67*H to obtain the layered plate. The layered plate is subjected to friction stir welding and T6 heat treatment in sequence to obtain the layered aluminum-based composite plate. The intermediate layer powder is a mixture of ceramic powder and first aluminum alloy powder. The T6 heat treatment includes: solution treatment at 500~550℃ for 4~8 hours, water quenching, aging at 150~200℃ for 5~10 hours, and then air cooling. The lower surface of the composite layer material has an uneven structure, which includes multiple protrusions. The first aluminum alloy powder, by mass percentage, comprises: 1-2 wt% copper, 0.8-1 wt% magnesium, 2-3 wt% silicon, 0.1-0.5 wt% titanium, 0.05-0.2 wt% tin, 0.2-0.3 wt% Sc, 0.2-0.3 wt% Ce and the balance aluminum; The aspect ratio of the ceramic powder in the intermediate layer is 1.31~1.45, and the D50 of the ceramic powder is 5~15μm. The ceramic powder is one or more of silicon carbide, boron nitride, alumina, titanium oxide and titanium boride.

2. The preparation method according to claim 1, characterized in that, Each protrusion is strip-shaped, and multiple protrusions are arranged horizontally.

3. The preparation method according to claim 2, characterized in that, The feed direction of the friction stir welding process is perpendicular to the length direction of the strip. During the friction stir welding process, the stirring needle needs to pass through the composite layer plate and extend into the base layer plate to a depth of 2-3 mm. The length of the stirring needle is 7-24 mm. The feed speed of the stirring head during the friction stir welding process is 200-350 mm / min, the rotation speed of the stirring needle is 1000-1200 r / min, the pressing amount of the stirring head is 0.2-0.3 mm, the path of the friction stir welding process covers the entire upper surface of the composite layer plate, and the angle between the shoulder surface of the stirring head and the upper surface of the composite layer plate is 1°-5°.

4. The preparation method according to claim 2, characterized in that, Each protrusion is a horizontally arranged triangular prism with one facet horizontally positioned. The other two faces of the prism serve as the lower surface of the composite layer and are located below the horizontal facet. All protrusions are arranged parallel to each other along their length and are arranged laterally. Any two adjacent protrusions form a recess, and the protrusions and recesses together form the convex-concave structure.

5. The preparation method according to claim 2, characterized in that, Each protrusion is a horizontally arranged column. All protrusions are arranged parallel to each other along their length and are spaced apart laterally. The bottom surface of the column is either planar or non-planar. Any two adjacent protrusions form a recess, and the protrusions and recesses together form the convex-concave structure.

6. The preparation method according to claim 1, characterized in that, The thickness of the composite layer plate is 4~15mm, and the thickness of the intermediate powder layer on the substrate plate is 6~10mm.

7. The preparation method according to claim 1, characterized in that, The method for preparing the intermediate layer powder includes: heat-treating ceramic powder at 1000~1200℃ for 1~5h under a protective atmosphere, and then mixing it evenly with the first aluminum alloy powder to obtain the intermediate layer powder, wherein the ratio of ceramic powder to the first aluminum alloy powder by volume is (1~6):

9.

8. The preparation method according to claim 1, characterized in that, The method for preparing the substrate layer plate includes: melting ZL101A aluminum alloy material at 600~800℃, adding Al-Cu master alloy, Al-Sr alloy and refining agent to obtain a mixture, degassing and refining the mixture under argon atmosphere, and then casting to obtain a casting as the substrate layer plate. The mixture contains 2~3.5 wt% copper, 0.01~0.1 wt% Al-Sr alloy, 10~15 wt% Sr in the Al-Sr alloy, and 0.5~2.5 wt% refining agent.

9. The preparation method according to claim 1, characterized in that, The method for preparing the composite layer board includes the following steps: Step 1) The silicon carbide powder is heat-treated under a protective atmosphere at a temperature of 1000~1200℃ for 1~5h. The heat-treated silicon carbide powder is then mixed evenly with the second aluminum alloy powder to obtain a first mixture. The first mixture is then cold-pressed, degassed under vacuum, and sintered at 450~600℃ for 1~10h. The mixture is then hot-pressed to obtain a blank. The ratio of silicon carbide powder to second aluminum alloy powder in the first mixture is (1~6):9 by volume. The second aluminum alloy powder comprises, by mass percentage: 1~2 wt% copper, 0.8~1 wt% magnesium, 2~3 wt% silicon, 0.1~0.5 wt% titanium, 0.05~0.2 wt% tin, and the balance aluminum. Step 2) The blank obtained in Step 1) isothermally extruded at 400~500℃ to obtain a sheet material. The lower surface of the sheet material is milled or ground to form the concave-convex structure, thus obtaining a composite layer sheet material.

10. The preparation method according to claim 1, characterized in that, The structure of the layered aluminum matrix composite material, from top to bottom, consists of a composite layer formed by composite layer plates, an intermediate layer formed by a pre-treated intermediate layer, and a matrix layer formed by a matrix layer plate. The coefficient of thermal expansion of the composite layer is 12~16×10⁻⁶ within the temperature range of 0~300℃. -6 / K, the coefficient of thermal expansion of the intermediate layer is 15~20×10 -6 / K, the coefficient of thermal expansion of the substrate layer is 21~25×10 -6 / K.

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