A heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material and its preparation method

Abstract

This invention belongs to the field of aluminum-based composite material technology, specifically relating to a heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material and its preparation method. Based on the total mass of the aluminum-based composite material, it includes an aluminum alloy matrix and 15%–25% by mass of SiC particle reinforcement. The SiC particle reinforcement is a mixture of micron-sized and submicron-sized particles. The micron-sized particles have a diameter of 10–100 μm, and the submicron-sized particles have a diameter of 0.3–0.8 μm. The submicron-sized particles account for 0.1%–2% of the total mass of the composite material. This invention exhibits excellent wear resistance and good heat cycle resistance from room temperature to 300°C. The resulting SiC particle aluminum-based composite brake disc avoids excessive degradation of material hardness, wear resistance, and coefficient of friction due to thermal cycling during repeated braking.

Description

Technical Field

[0001] This invention relates to the field of aluminum-based composite materials technology, and in particular to a heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material and its preparation method. Background Technology

[0002] Aluminum-based composite materials have become a hot topic in recent years due to their low density, high specific strength, specific stiffness, and excellent thermal conductivity. Among them, SiC particle-reinforced aluminum-based composites represent a new class of materials that have achieved breakthroughs in aerospace, electronic packaging, automotive manufacturing, and high-speed trains. Currently, the main preparation methods for SiC particle aluminum-based composites include stir casting, powder metallurgy, and pressure infiltration. Stir casting involves externally stirring molten aluminum alloy to incorporate SiC particles into the melt, resulting in a uniformly distributed melt, which is then cast under specific forming conditions to obtain aluminum-based composite parts. Stir casting boasts low production costs, high efficiency, and simple equipment and processes, making it one of the most promising technologies for large-scale industrial production.

[0003] For SiC particle aluminum matrix composites used in friction components, the operating conditions often involve simultaneous frictional heating and braking pressure, making them prone to performance degradation. In particular, the material's hardness, strength, and wear resistance decrease with thermal cycling. This is mainly because the matrix of SiC particle aluminum matrix composites is generally a cast aluminum alloy system, whose aluminum phase has poor heat resistance and limited heat-strengthening phases. Furthermore, in aluminum matrix composites prepared using stir casting, SiC tends to agglomerate in the eutectic structure during solidification, making it difficult to effectively strengthen the primary aluminum phase. Therefore, improving the thermal cycling resistance and wear resistance of composite materials through matrix composition design and SiC particle size design has become crucial for the practical application of SiC particle aluminum matrix composites.

[0004] For example, patent CN113957297B discloses a SiC particle aluminum matrix composite material with good heat resistance and its preparation method. The method involves introducing elements such as Fe, V, Cu, and Ni into the composite material using powder metallurgy, thereby generating Al within the microstructure. 13 Strengthening phases such as (Fe,V)3Si and Al2Cu are used to improve high-temperature strength and hardness. However, this composition design is only suitable for high-cost powder metallurgy processes, with Al being the main strengthening phase. 13 (Fe,V)3Si is a metastable phase, requiring sintering and subsequent hot forging processes to be limited to temperatures not exceeding 500°C or with short dwell times; otherwise, this reinforcing phase will transform into stable phases such as Al3Fe, thus deteriorating performance. Furthermore, this composition design cannot guarantee the fluidity and casting properties of the molten metal, making it unsuitable for low-cost stir casting processes.

[0005] CN115595477B discloses an aluminum-based composite material with strong interfacial bonding, high temperature resistance, and wear resistance, and its preparation method. Based on the total mass of the aluminum-based composite material, it includes 10%–30% by mass of reinforcement, with the balance being aluminum alloy. The reinforcement comprises ceramic particles and Al2O3 fibers. The ceramic particles are at least one of SiC, B4C, and Al2O3 particles, and the particle size of the ceramic particles is 8–20 μm. The as-cast tensile strength of the aluminum-based composite material at 300℃ is ≥150 MPa, and its tensile strength at 350℃ is ≥130 MPa. Summary of the Invention

[0006] To address the problems in the prior art, this invention proposes a heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material and its preparation method.

[0007] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0008] A heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material, based on the total mass of the aluminum-based composite material, includes an aluminum alloy matrix and 15% to 25% by mass of SiC particle reinforcement. The SiC particle reinforcement is a mixture of micron-sized particles and submicron-sized particles, with the micron-sized particles having a particle size of 10 to 100 μm and the submicron-sized particles having a particle size of 0.3 to 0.8 μm. The amount of submicron-sized particles added accounts for 0.1% to 2% of the total mass of the composite material.

[0009] Furthermore, the SiC particle reinforcement undergoes a pre-oxidation process, resulting in an oxide layer covering the surface. The thickness of the oxide layer differs between the micron-sized particles and the submicron-sized particles.

[0010] Furthermore, the thickness of the oxide layer on the surface of micron-sized particles is greater than that on the surface of submicron-sized particles.

[0011] Furthermore, the composition of the aluminum alloy matrix, based on the mass fraction of the aluminum alloy matrix as 100%, is as follows: Si: 6.5%-12%, Cu: 2%-6%, Ni: 1%-3%, Mg: 0.5%-1.5%, Fe: 0.05%-0.2%, Ti: 0.01%-0.2%, Mn: 0.1%-0.5%, Cr: 0.01%-0.4%, Zr: 0.05%-0.2%, Y: 0.02%-0.2%, V: 0.02%-0.1%; the balance being Al and unavoidable impurities.

[0012] Furthermore, the aluminum alloy matrix is ​​a hypoeutectic aluminum-silicon alloy, with micron-sized particles distributed in the eutectic structure and submicron-sized particles distributed in the eutectic structure and the primary aluminum phase.

[0013] Furthermore, the composite material comprises a primary aluminum phase and a micron-scale network reinforcement structure. The network reinforcement structure comprises silicon carbide, eutectic Si, and one or more intermetallic compound reinforcement phases. The size of the intermetallic compound reinforcement phase is 5-40 μm, and its volume percentage in the composite structure is ≥4%. The room temperature nanohardness value is 6-12 GPa, and the nanohardness value at 350℃ is 4-8 GPa.

[0014] Furthermore, the intermetallic compound strengthening phase includes Al3CuNi, Al3Ni, Al7Cu4Ni, and AlSi(FeMn)CuNi.

[0015] Furthermore, the aluminum-based composite material has a room temperature tensile strength of not less than 300 MPa, a 300°C tensile strength of not less than 205 MPa, and a hardness increase of 0-10% after 900 cycles of thermal mismatch strengthening at 30°C to 300°C.

[0016] Furthermore, the preparation method of the heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material involves preparing aluminum alloy raw materials according to the component ratio and heating and melting them.

[0017] After pretreatment of silicon carbide particles, they are added to the melt and stirred to obtain an aluminum-based composite melt. The aluminum-based composite melt is then cast to obtain a silicon carbide aluminum-based composite material.

[0018] Furthermore, the pretreatment includes pickling, ball milling, sieving and oxidation. The oxidation process for micron-sized particles is oxidized at 900-1200℃ for 2-6 hours, and the oxidation process for submicron-sized particles is oxidized at 700-900℃ for 0.5-2 hours.

[0019] Compared to existing technologies, the SiC particle aluminum-based composite material prepared by the above method exhibits excellent wear resistance and good thermal cycling resistance from room temperature to 300℃. When used to prepare a SiC particle aluminum-based composite brake disc, it can prevent excessive degradation of material hardness, wear resistance, and coefficient of friction due to thermal cycling during repeated braking. Attached Figure Description

[0020] To more clearly illustrate the content and specific embodiments of this invention, the accompanying drawings required for the description process are introduced. The following drawings are merely for the purpose of illustrating the subject matter of this invention. Those skilled in the art can readily provide other similar drawings based on the drawings in this invention without any inventive effort.

[0021] Figure 1 The microstructure of the heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material manufactured according to an embodiment of the present invention.

[0022] Figure 2The characteristics of the primary aluminum phase internal reinforcing phase in the heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material manufactured according to the present invention.

[0023] Figure 3 This is a graph showing the change in hardness due to thermal cycling of the aluminum-based composite material manufactured in an embodiment of the present invention.

[0024] Figure 4 Bench test results of the heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite brake disc manufactured according to this invention.

[0025] Figure 5 The SiC and matrix interfaces of the aluminum-based composite material manufactured in this invention contain micro-rivet-like MgAl2O4. Detailed Implementation

[0026] The present invention will now be described in detail with reference to embodiments and accompanying drawings. However, it should be understood that the embodiments and drawings are for illustrative purposes only and do not constitute any limitation on the scope of protection of the present invention. All reasonable modifications and combinations included within the inventive spirit of the present invention fall within the scope of protection of the present invention.

[0027] A heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material, based on the total mass of the aluminum-based composite material, includes an aluminum alloy matrix and 15% to 25% by mass of SiC particle reinforcement. The SiC particle reinforcement is a mixture of micron-sized and submicron-sized particles, with micron-sized particles having a particle size of 10 to 100 μm and submicron-sized particles having a particle size of 0.3 to 0.8 μm. The amount of submicron-sized particles added accounts for 0.1% to 2% of the total mass of the composite material.

[0028] The aforementioned SiC particle reinforcement design effectively balances the wear resistance and thermal cycling resistance of the composite material. Micron-sized particles enhance the composite's strength and hardness through load transfer, acting as the primary wear-resistant particles during friction to improve wear resistance. Submicron-sized SiC, due to its different coefficient of thermal expansion compared to the aluminum matrix, strengthens the primary aluminum phase during thermal cycling by inducing numerous thermally mismatched dislocations and entanglement within the primary aluminum phase through a thermal mismatch effect, thus suppressing the degradation of matrix properties during thermal cycling.

[0029] Furthermore, the SiC particle reinforcement undergoes a pre-oxidation process, resulting in an oxide layer covering its surface.

[0030] Furthermore, the thickness of the oxide layer on the surface of micron-sized particles differs from that of submicron-sized particles.

[0031] Furthermore, the thickness of the oxide layer on the surface of micron-sized particles is greater than that on the surface of submicron-sized particles.

[0032] Furthermore, the morphology of the oxide layer on the surface of micron-sized particles is also different from that of submicron-sized particles.

[0033] Furthermore, the oxide layer thickness on the surface of micron-sized particles is 50-500 nm, exhibiting a dotted distribution. The oxide layer thickness on the surface of submicron-sized particles is 20-200 nm, providing complete coverage.

[0034] Furthermore, the aluminum alloy matrix contains magnesium, and the dotted oxide layer on the surface of the micron-sized particles is composed of SiO2, which reacts with aluminum and magnesium elements in the matrix melt to form microscopic rivet-like MgAl2O4, such as... Figure 5 As shown, this enhances the interfacial bonding between the particles and the Al matrix; the surface of the submicron particles is completely covered with SiO2, improving the wettability between the matrix melt and the particles, thereby reducing the difficulty of adding submicron particles.

[0035] Furthermore, the composition of the aluminum alloy matrix, based on the mass fraction of the aluminum alloy matrix as 100%, is as follows: Si: 6.5%-12%, Cu: 2%-6%, Ni: 1%-3%, Mg: 0.5%-1.5%, Fe: 0.05%-0.2%, Ti: 0.01%-0.2%, Mn: 0.1%-0.5%, Cr: 0.01%-0.4%, Zr: 0.05%-0.2%, Y: 0.02%-0.2%, V: 0.02%-0.1%; the balance being Al and unavoidable impurities.

[0036] Furthermore, the mass percentages of each element conform to the following relationships: Cu / Ni = 1.5~3; Ni+Zr+Mg+Cu = 4~9%.

[0037] Furthermore, the mass percentages of each element conform to the following relationship: Fe / V = 0.1~3; Mn+Cr≤0.6.

[0038] Furthermore, the aluminum alloy is a hypoeutectic aluminum-silicon alloy, with micron-sized particles distributed in the eutectic structure and submicron-sized particles distributed in the eutectic structure and the primary aluminum phase, forming a synergistic strengthening effect.

[0039] The aforementioned hypoeutectic aluminum-silicon alloy system exhibits excellent casting performance, ensuring melt fluidity and facilitating the formation of sufficient melt vortices to entrain SiC particles during stirring; it also ensures mold filling fluidity during the casting process.

[0040] Furthermore, the composite material comprises a primary aluminum phase and a micron-scale network reinforcement structure. The network reinforcement structure comprises silicon carbide, eutectic Si, and one or more intermetallic compound reinforcement phases. The size of the intermetallic compound reinforcement phase is 5-40 μm, and its volume percentage in the composite structure is ≥4%. The room temperature nanohardness value is 6-12 GPa, and the nanohardness value at 350℃ is 4-8 GPa.

[0041] Furthermore, the intermetallic compound strengthening phase includes Al3CuNi, Al3Ni, Al7Cu4Ni, and AlSi(FeMn)CuNi.

[0042] Furthermore, the primary aluminum phase is reinforced by nano-precipitates, which are selected from nano-precipitates containing one or more elements such as Al, Si, Mg, Fe, Mn, Cr, Zr, Y, and V. The precipitates are needle-shaped and short rod-shaped with a size of 10-400 nm. The nano-precipitates are kept at 350℃ for 30 h, and the size coarsening ratio is ≤8%.

[0043] Furthermore, the percentage of SiC in the composite material and the percentage of Mg in the alloy matrix are related as follows: SiC / Mg = 13~25.

[0044] The composite material designed according to the above requirements exhibits good wettability between SiC particles and the matrix melt. During the addition of SiC particles, the particles are easily entrained by the melt vortex without agglomeration. Simultaneously, the Mg content is controlled to avoid excessive levels that could affect the high-temperature resistance of the matrix.

[0045] Furthermore, the aluminum-based composite material has a room temperature tensile strength of not less than 300 MPa, a 300°C tensile strength of not less than 205 MPa, and a hardness increase of 0-10% after 900 cycles of thermal mismatch strengthening at 30°C to 300°C.

[0046] Furthermore, the preparation method of the heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material involves preparing aluminum alloy raw materials according to the component ratio and heating and melting them.

[0047] After pretreatment of silicon carbide particles, they are added to the melt and stirred to obtain an aluminum-based composite melt. The aluminum-based composite melt is then cast to obtain a silicon carbide aluminum-based composite material.

[0048] The pretreatment includes pickling, ball milling, sieving and oxidation. The oxidation process for micron-sized particles is to oxidize at 900-1200℃ for 2-6 hours, and the oxidation process for submicron-sized particles is to oxidize at 700-900℃ for 0.5-2 hours.

[0049] By controlling the oxidation process described above, particles of different sizes can be coated with an oxide layer of appropriate thickness to improve wettability with the melt and interfacial bonding strength with the matrix.

[0050] Furthermore, the specific steps include the following:

[0051] (1) Preparation of matrix raw materials: Prepare aluminum alloy raw materials according to the composition ratio, and clean and dry them;

[0052] (2) Silicon carbide pretreatment: Silicon carbide particles are pretreated, including pickling, ball milling, oxidation and sieving;

[0053] (3) Preparation of aluminum melt: The aluminum alloy raw material is placed in a crucible and heated and melted under certain vacuum conditions to obtain aluminum alloy melt;

[0054] (4) Addition of silicon carbide particles: Stir the melt with a stirring head and add the pretreated silicon carbide particles into the melt, and further stir and disperse to obtain aluminum-based composite melt;

[0055] (5) Casting: Increase the temperature and inject the aluminum-based composite melt into the preheated brake disc mold by pressure casting or gravity casting. Cool and solidify to obtain a silicon carbide aluminum-based composite material in the shape of a brake disc.

[0056] Furthermore, the silicon carbide aluminum-based composite material does not exhibit thermal fatigue cracks at the prefabricated notch after 700 cycles at 30℃~300℃.

[0057] Furthermore, the silicon carbide aluminum-based composite material, when braked from 100 km / h to 5 km / h at a deceleration of 0.4g, maintains a friction coefficient of 0.3-0.4 after 15 braking cycles.

[0058] Example 1

[0059] An aluminum-based composite material, wherein SiC particles comprise 21% of the total weight of the composite material, of which 20% are micron-sized SiC with an average particle size of 15 μm and 1% are submicron-sized SiC with an average particle size of 0.6 μm.

[0060] The aluminum alloy composition by weight is as follows: Si: 10%, Cu: 3%, Ni: 2%, Mg: 1%, Mn: 0.5%, Cr: 0.1%, Fe: 0.05%, Zr: 0.2%, V: 0.02%, Y: 0.02%, Ti: 0.15%.

[0061] The preparation method of the above aluminum-based composite material is as follows:

[0062] The alloy material was ultrasonically cleaned with alcohol for 15 minutes at a temperature of 40°C. After cleaning, it was placed in a drying oven and dried at 100°C for 30 minutes.

[0063] The SiC raw material has a purity greater than 99%. It is cleaned by stirring with a 5% HF solution, followed by rinsing with distilled water to obtain a slurry. The slurry is then ball-milled using a horizontal low-energy ball mill with silicon carbide grinding balls of 5-10 mm diameter. The volume ratio of SiC slurry to grinding balls is 1:1.5, the milling speed is 130 r / min, and the time is 20 h. After ball milling, the slurry is removed and dried. The dried SiC raw material is then oxidized: micron-sized SiC is oxidized at 1100℃ for 3 hours under atmospheric conditions, and submicron-sized SiC is oxidized at 850℃ for 40 minutes under atmospheric conditions. After oxidation, the material is naturally cooled and then vibrated and sieved.

[0064] The alloy raw material is placed in a crucible of a vacuum induction melting furnace equipped with a stirring device. After evacuating to 10 Pa, the temperature is raised to 700℃ and held for 0.5 h to fully melt. The temperature of the melt is then lowered to 570-590℃, and the stirring head is inserted below the liquid surface. The mixture is stirred at a uniform speed of 500 r / min.

[0065] SiC is added to the central vortex of the molten aluminum alloy using a secondary feeding device. After the silicon carbide is added, the vacuum is reduced to 10 Pa, the rotation speed is increased to 800 r / min, and stirring is continued at 570-580℃ for 1.5 h.

[0066] Reduce the stirring speed to 200 r / min and raise the temperature of the aluminum composite melt to 700℃. Maintain a vacuum of 5-10 Pa and hold for 15 min. Stop stirring and remove the stirring head. Raise the temperature of the aluminum composite melt to 730℃ and use gravity casting to obtain an aluminum composite ingot and pressure-controlled casting to prepare an aluminum composite brake disc.

[0067] The microstructure of the aluminum-based composite material prepared in this embodiment is as follows: Figure 1 As shown, the characteristics of the reinforcing phase within the primary aluminum phase are as follows: Figure 2 As shown, SiC is uniformly distributed without obvious agglomeration. A network of reinforcing phases, including silicon carbide, eutectic Si, Al3CuNi, and AlSi(FeMn)CuNi, forms the core. The primary aluminum is synergistically reinforced by submicron-sized SiC, AlSiZr, and AlSiCrMn nano-precipitates. The material has a room temperature tensile strength of 300 MPa and a tensile strength of 205 MPa at 300℃. It exhibits excellent thermal fatigue resistance in thermal fatigue tests; after 700 cycles at 30℃~300℃, no significant thermal fatigue cracks were observed at the pre-formed notch, and the hardness did not show significant degradation after 900 thermal cycles. Figure 3 As shown. The prepared aluminum-based composite brake disc was subjected to a 1:1 bench test, braking from 100 km / h to 5 km / h with a deceleration of 0.4g, for a total of 15 braking cycles, as shown. Figure 4 As shown, the temperature rises to a maximum of 258℃, and its friction coefficient does not decline significantly, remaining stable at 0.3-0.4.

[0068] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made based on the content of this specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the protection scope of this application.

Claims

1. A heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material, characterized in that, Based on the total mass of the aluminum-based composite material, it includes an aluminum alloy matrix and 15%–25% by mass of SiC particle reinforcement. The SiC particle reinforcement is a mixture of micron-sized and submicron-sized particles, with micron-sized particles having a particle size of 10–100 μm and submicron-sized particles having a particle size of 0.3–0.8 μm. The amount of submicron-sized particles added accounts for 0.1%–2% of the total mass of the composite material. The SiC particle reinforcement undergoes a pre-oxidation process, and its surface is covered with an oxide layer; the thickness of the oxide layer on the surface of micron-sized particles is greater than the thickness of the oxide layer on the surface of submicron-sized particles. The oxide layer on the surface of micron-sized particles is composed of SiO2, with a thickness of 50-500 nm, and is distributed in a dotted pattern. The oxide layer on the surface of submicron-sized particles is also composed of SiO2, with the surface of submicron-sized particles completely covered by SiO2 and a thickness of 20-200 nm.

2. The heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material according to claim 1, characterized in that, The aluminum alloy matrix composition, based on the mass fraction of the aluminum alloy matrix as 100%, is as follows: Si: 6.5%-12%, Cu: 2%-6%, Ni: 1%-3%, Mg: 0.5%-1.5%, Fe: 0.05%-0.2%, Ti: 0.01%-0.2%, Mn: 0.1%-0.5%, Cr: 0.01%-0.4%, Zr: 0.05%-0.2%, Y: 0.02%-0.2%, V: 0.02%-0.1%; the balance being Al and unavoidable impurities.

3. The heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material according to claim 2, characterized in that, The aluminum alloy matrix is ​​a hypoeutectic aluminum-silicon alloy, with micron-sized particles distributed in the eutectic structure and submicron-sized particles distributed in both the eutectic structure and the primary aluminum phase.

4. The heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material according to claim 3, characterized in that, The composite material comprises a primary aluminum phase and a micron-scale network reinforcement structure. The network reinforcement structure comprises silicon carbide, eutectic Si, and one or more intermetallic compound reinforcement phases. The size of the intermetallic compound reinforcement phase is 5-40 μm, and its volume percentage in the composite structure is ≥4%. The room temperature nanohardness value is 6-12 GPa, and the nanohardness value at 350℃ is 4-8 GPa.

5. The heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material according to claim 4, characterized in that, The intermetallic compound strengthening phases include Al3CuNi, Al3Ni, Al7Cu4Ni, and AlSi(FeMn)CuNi.

6. The heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material according to claim 5, characterized in that, The aluminum-based composite material has a room temperature tensile strength of not less than 300 MPa and a 300℃ tensile strength of not less than 205 MPa. Under 900 cycles of thermal mismatch strengthening at 30℃ to 300℃, the hardness increases by 0 to 10%.

7. The method for preparing the heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material according to claim 6, characterized in that, The aluminum alloy raw materials were prepared according to the component ratio and then heated and melted. After pretreatment of silicon carbide particles, they are added to the melt and stirred to obtain an aluminum-based composite melt. The aluminum-based composite melt is then cast to obtain a silicon carbide aluminum-based composite material.

8. The preparation method according to claim 7, characterized in that, The pretreatment includes pickling, ball milling, sieving and oxidation. The oxidation process for micron-sized particles is to oxidize at 900-1200℃ for 2-6 hours, and the oxidation process for submicron-sized particles is to oxidize at 700-900℃ for 0.5-2 hours.

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