Heat-resistant cyclic wear-resistant aluminum-based composite material and preparation method thereof

Abstract

The invention belongs to the technical field of aluminum-based composite materials, and particularly relates to a heat-resistant cyclic wear-resistant aluminum-based composite material and a preparation method thereof.Based on the total mass of the aluminum-based composite material, the heat-resistant cyclic wear-resistant aluminum-based composite material comprises an aluminum alloy matrix and a SiC particle reinforcement with the mass fraction of 15%-25%, and the SiC particle reinforcement is a mixture of micron-sized particles and submicron-sized particles; the particle size of the micron-sized particles is 10-100 [mu] m, the particle size of the submicron-sized particles is 0.3-0.8 [mu] m, the addition amount of the submicron-sized particles accounts for 0.1-2% of the total mass of the composite material, and the composite material has good wear resistance and good heat-resistant cycle performance at the normal temperature of minus 300 DEG C. The prepared SiC particle aluminum-based composite material brake disc can avoid excessive decline of material hardness, wear resistance and friction coefficient caused by thermal cycle in a repeated braking process.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum-based composite materials, and in particular to a heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material and a preparation method thereof. Background Art

[0002] Aluminum-based composite materials have become a hot topic of development in recent years due to their low density, high specific strength, specific stiffness, and excellent thermal conductivity. Among them, a class of new materials represented by SiC particle reinforced aluminum-based composite materials has continuously achieved breakthroughs in the fields of aerospace, electronic packaging, automobile manufacturing, and high-speed trains. At present, the main preparation methods of SiC particle aluminum-based composite materials are stirring casting, powder metallurgy, and pressure infiltration. Among them, the stirring casting method is a method in which SiC particles are rolled into the melt in the molten aluminum alloy by external stirring to obtain a uniformly distributed melt, and then cast under certain molding conditions to obtain aluminum-based composite parts. The stirring casting method has low production cost, high production efficiency, and simple equipment and process. It is one of the most promising processes for achieving large-scale industrial production.

[0003] For SiC particle aluminum-based composite materials used in friction parts, the working conditions are often subject to a certain amount of friction temperature rise and braking pressure at the same time, so they are prone to performance degradation, especially the hardness, strength and wear resistance of the material will decrease with the progress of thermal cycling. This is mainly because the matrix of SiC particle aluminum-based composite materials is generally a cast aluminum alloy system, the heat resistance of the aluminum phase in its structure is poor, and the heat-resistant strengthening phase is limited; at the same time, in aluminum-based composite materials prepared by stirring casting, SiC will be segregated in the eutectic structure during solidification, making it difficult to effectively strengthen the primary aluminum phase. Therefore, how to improve the heat cycle resistance and wear resistance of the composite material through matrix composition design and SiC particle size design has become the key to the practical application of SiC particle aluminum-based composite materials.

[0004] For example, in patent CN113957297B, a SiC particle aluminum-based composite material with good heat resistance and its preparation method is disclosed. Elements such as Fe, V, Cu, and Ni are introduced into the composite material through a powder metallurgy preparation method to generate Al in the organization. 13 (Fe, V) 3Si and Al2Cu are strengthening phases to improve high temperature strength and hardness. However, this composition design is only suitable for high-cost powder metallurgy process. 13 (Fe,V)3Si is a metastable phase, requiring sintering and subsequent hot forging processes to be limited to temperatures below 500°C or dwell times to be short. Otherwise, this strengthening phase will transform into stable phases like Al3Fe, deteriorating performance. Furthermore, this composition design cannot guarantee the fluidity and casting properties of the molten metal, making it difficult to apply to 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. The composite material comprises a reinforcement comprising 10% to 30% by mass, based on the total mass of the composite material, with the remainder being an aluminum alloy. The reinforcement comprises ceramic particles and Al2O3 fibers. The ceramic particles are at least one of SiC, B4C, and Al2O3 particles, and have a particle size of 8 to 20 μm. The composite material exhibits a tensile strength of 150 MPa or greater at 300°C and 130 MPa or greater at 350°C. Summary of the Invention

[0006] In view of the problems in the prior art, the present invention proposes a heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material and a preparation method thereof.

[0007] The technical solution adopted by the present invention to solve the above technical problems is: A heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material comprises, based on the total mass of the aluminum-based composite material, an aluminum alloy matrix and 15% to 25% by mass of a SiC particle reinforcement. The SiC particle reinforcement is a mixture of micron-sized particles and submicron-sized particles. The micron-sized particles have a particle size of 10 to 100 μm, and the submicron-sized particles have 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.

[0008] Furthermore, the SiC particle reinforcement is pre-oxidized, and its surface is covered with an oxide layer. The thickness of the oxide layer on the surface of the micron-sized particles is different from that on the surface of the submicron-sized particles.

[0009] Furthermore, the thickness of the oxide layer on the surface of the micron-sized particles is greater than the thickness of the oxide layer on the surface of the submicron-sized particles.

[0010] Furthermore, the composition of the aluminum alloy matrix, based on the mass fraction of the aluminum alloy matrix as 100%, the mass percentage of each element is, 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 remainder is Al and unavoidable impurities.

[0011] Furthermore, the aluminum alloy matrix is a hypoeutectic aluminum-silicon alloy, micron-sized particles are distributed in the eutectic structure, and submicron-sized particles are distributed in the eutectic structure and the primary aluminum phase.

[0012] Furthermore, the composite material includes a primary aluminum phase and a micron-scale network reinforcement structure, the network reinforcement structure includes silicon carbide, eutectic Si and one or more intermetallic compound reinforcement phases, the size of the intermetallic compound reinforcement phase is 5-40μm, the volume percentage in the composite structure is ≥4%, the room temperature nanohardness value is 6~12 GPa, and the nanohardness value at 350°C is 4~8GPa.

[0013] Furthermore, the intermetallic compound strengthening phase includes Al3CuNi, Al3Ni, Al7Cu4Ni, and AlSi(FeMn)CuNi. Furthermore, the tensile strength of the aluminum-based composite material at room temperature is not less than 300 MPa, the tensile strength at 300°C is not less than 205 MPa, and the hardness is increased by 0-10% after 900 thermal mismatch strengthening cycles at 30°C-300°C.

[0014] Furthermore, the preparation method of the heat-resistant, cycle-resistant and wear-resistant aluminum-based composite material comprises preparing aluminum alloy raw materials according to the component ratio and heating and melting them. After pre-treating the silicon carbide particles, the particles are added into the melt and stirred to obtain an aluminum-based composite melt, and the aluminum-based composite melt is poured to obtain a silicon carbide aluminum-based composite material.

[0015] Furthermore, the pretreatment includes pickling, ball milling, screening and oxidation. The oxidation process of micron-sized particles is oxidation at 900-1200° C. for 2-6 hours, and the oxidation process of submicron-sized particles is oxidation at 700-900° C. for 0.5-2 hours.

[0016] Compared to existing technologies, the SiC particle aluminum-based composite material prepared by the above method has excellent wear resistance and good thermal cycling resistance at room temperature to -300°C. Brake discs made from the SiC particle aluminum-based composite material can avoid excessive degradation of material hardness, wear resistance, and friction coefficient caused by thermal cycling during repeated braking. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] To more clearly illustrate the content of the present invention and specific implementation examples, the following drawings are necessary for the description process. The following drawings are merely for the purpose of illustrating the subject matter of the present invention. Those skilled in the art can easily provide other similar drawings based on the drawings in the present invention without inventive effort.

[0018] Figure 1 The microstructure of the heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material manufactured in an embodiment of the present invention.

[0019] Figure 2 The invention discloses a reinforcing phase characteristic within the primary aluminum phase of the heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material.

[0020] Figure 3 This is a graph showing the change in hardness of the aluminum-based composite material manufactured in accordance with an embodiment of the present invention during thermal cycling.

[0021] Figure 4 These are the bench test results of the heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite brake disc manufactured by the present invention.

[0022] Figure 5 The invention discloses microscopic rivet-shaped MgAl2O4 at the interface between SiC and the matrix of the aluminum-based composite material. DETAILED DESCRIPTION

[0023] The present invention is described in detail below with reference to the embodiments and accompanying drawings. However, it should be understood that the embodiments and accompanying drawings are merely exemplary descriptions of the present invention and do not constitute any limitation on the scope of protection of the present invention. All reasonable variations and combinations within the scope of the inventive concept of the present invention fall within the scope of protection of the present invention.

[0024] A heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material comprises, based on the total mass of the aluminum-based composite material, an aluminum alloy matrix and 15% to 25% by mass of a SiC particle reinforcement. The SiC particle reinforcement is a mixture of micron-sized and submicron-sized particles, wherein the micron-sized particles have a particle size of 10 to 100 μm, and the submicron-sized particles have 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.

[0025] The SiC particle reinforcement ratio design can coordinate the wear resistance and thermal cycling performance of the composite material. The micron-sized particles enhance the strength and hardness of the composite material through load transfer reinforcement, acting as the primary wear-resistant particles during the friction process to improve wear resistance. Due to its different thermal expansion coefficient from the aluminum matrix, the submicron-sized SiC stimulates a large number of thermal mismatch dislocations within the primary aluminum phase during thermal cycling through the thermal mismatch effect, causing them to entangle and strengthen the primary aluminum phase, thereby suppressing matrix performance degradation during thermal cycling.

[0026] Furthermore, the SiC particle reinforcement is pre-oxidized and its surface is covered with an oxide layer.

[0027] Furthermore, the thickness of the oxide layer on the surface of micron-sized particles is different from that of the surface of submicron-sized particles.

[0028] Furthermore, the thickness of the oxide layer on the surface of the micron-sized particles is greater than the thickness of the oxide layer on the surface of the submicron-sized particles.

[0029] Furthermore, the morphology of the oxide layer on the surface of micron-sized particles is also different from that of submicron-sized particles.

[0030] Furthermore, the surface oxide layer of micron-sized particles has a thickness of 50-500nm and is distributed in a dotted pattern, while the surface oxide layer of submicron-sized particles has a thickness of 20-200nm and is completely covered.

[0031] Furthermore, the aluminum alloy matrix contains magnesium, and the dot-shaped oxide layer on the surface of the micron-sized particles is composed of SiO2, which reacts with the aluminum and magnesium elements in the matrix melt to form microscopic rivet-shaped MgAl2O4, such as Figure 5 As shown, the interface bonding force between the particles and the Al matrix is enhanced; the surface of the submicron particles is completely covered with SiO2, which improves the wettability between the matrix melt and the particles, thereby reducing the difficulty of adding submicron particles.

[0032] Furthermore, the composition of the aluminum alloy matrix, based on the mass fraction of the aluminum alloy matrix as 100%, the mass percentage of each element is, 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 remainder is Al and unavoidable impurities.

[0033] Furthermore, the mass proportions of each element conform to the following relationship: Cu / Ni=1.5~3; Ni+Zr+Mg+Cu= 4~9%.

[0034] Furthermore, the mass proportion of each element conforms to the following relationship: Fe / V= 0.1~3; Mn+Cr≤0.6.

[0035] Furthermore, the aluminum alloy is a hypoeutectic aluminum-silicon alloy, micron-sized particles are distributed in the eutectic structure, and submicron-sized particles are distributed in the eutectic structure and the primary aluminum phase, forming a synergistic strengthening effect.

[0036] The above hypoeutectic aluminum-silicon alloy system has excellent casting performance, can ensure the fluidity of the melt, facilitates stirring to form sufficient melt vortex to entrain SiC particles; and ensures filling fluidity during the casting process.

[0037] Furthermore, the composite material includes a primary aluminum phase and a micron-scale network reinforcement structure, the network reinforcement structure includes silicon carbide, eutectic Si and one or more intermetallic compound reinforcement phases, the size of the intermetallic compound reinforcement phase is 5-40μm, the volume percentage in the composite structure is ≥4%, the room temperature nanohardness value is 6~12 GPa, and the nanohardness value at 350°C is 4~8GPa.

[0038] Furthermore, the intermetallic compound strengthening phase includes Al3CuNi, Al3Ni, Al7Cu4Ni, and AlSi(FeMn)CuNi. Furthermore, the primary aluminum phase is strengthened by a nano-precipitated phase, and the nano-precipitated phase is selected from a nano-precipitated phase containing one or more elements of Al, Si, Mg, Fe, Mn, Cr, Zr, Y, and V. The precipitated phase has a needle-like and short rod-like morphology and a size of 10-400 nm. The nano-precipitated phase is kept at 350° C. for 30 hours, and the size coarsening ratio is ≤8%.

[0039] Furthermore, the percentage of SiC in the composite mass and the percentage of Mg in the alloy matrix conform to the following relationship: SiC / Mg=13~25.

[0040] The composite material designed based on these requirements exhibits excellent wettability between the SiC particles and the matrix melt. During SiC particle addition, the particles are easily drawn into the melt vortex without agglomeration. Furthermore, the Mg content is controlled so that it does not affect the matrix's high-temperature resistance.

[0041] Furthermore, the tensile strength of the aluminum-based composite material at room temperature is not less than 300 MPa, the tensile strength at 300°C is not less than 205 MPa, and the hardness is increased by 0-10% after 900 thermal mismatch strengthening cycles at 30°C-300°C.

[0042] Furthermore, the preparation method of the heat-resistant, cycle-resistant and wear-resistant aluminum-based composite material comprises preparing aluminum alloy raw materials according to the component ratio and heating and melting them. After pre-treating the silicon carbide particles, the particles are added into the melt and stirred to obtain an aluminum-based composite melt, and the aluminum-based composite melt is poured to obtain a silicon carbide aluminum-based composite material.

[0043] The pretreatment includes pickling, ball milling, screening and oxidation. The oxidation process of micron-sized particles is oxidation at 900-1200° C. for 2-6 hours, and the oxidation process of submicron-sized particles is oxidation at 700-900° C. for 0.5-2 hours.

[0044] By regulating the above oxidation process, the surfaces of particles of different particle sizes are covered with an oxide layer of appropriate thickness to improve wettability with the melt and interfacial bonding strength with the substrate.

[0045] Furthermore, the following steps are specifically included: (1) Preparation of matrix raw materials: Prepare aluminum alloy raw materials according to the composition ratio, and clean and dry them; (2) Silicon carbide pretreatment: Pretreatment of silicon carbide particles, including pickling, ball milling, oxidation and screening; (3) Preparation of aluminum melt: Place the aluminum alloy raw material in a crucible and heat and melt it under certain vacuum conditions to obtain an aluminum alloy melt; (4) Adding silicon carbide particles: Stir the melt with a stirring head, add the pretreated silicon carbide particles into the melt, and further stir and break them up to obtain an aluminum-based composite melt; (5) Casting: Raise the temperature and inject the aluminum-based composite melt into the preheated brake disc mold by pressure casting or gravity casting, cool and shape it to obtain a silicon carbide aluminum-based composite material in the shape of a brake disc.

[0046] Furthermore, the silicon carbide aluminum-based composite material does not generate thermal fatigue cracks after being cycled 700 times at 30° C. to 300° C.

[0047] Furthermore, the silicon carbide aluminum-based composite material maintains a friction coefficient of 0.3-0.4 after braking from 100 km / h to 5 km / h at a deceleration of 0.4 g and 15 braking cycles.

[0048] Example 1 An aluminum-based composite material comprises 21% SiC particles based on the total weight of the composite material, wherein the content of micron-sized SiC particles with an average particle size of 15 μm is 20% and the content of submicron-sized SiC particles with an average particle size of 0.6 μm is 1%.

[0049] The aluminum alloy composition is as follows based on the weight of the matrix: 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%, and Ti: 0.15%.

[0050] The preparation method of the above-mentioned aluminum-based composite material is as follows: The alloy raw materials were ultrasonically cleaned with alcohol for 15 minutes at a cleaning temperature of 40°C. After cleaning, they were placed in a drying oven at 100°C for 30 minutes.

[0051] The SiC raw material, with a purity greater than 99%, was cleaned with a 5% HF solution by stirring and then rinsed with distilled water to obtain a slurry. The slurry was then milled in a horizontal low-energy ball mill using silicon carbide grinding balls with a diameter of 5-10 mm. The volume ratio of SiC slurry to grinding balls was 1:1.5, and the milling speed was 130 rpm for 20 hours. After milling, the slurry was removed and dried. The dried SiC raw material was oxidized at 1100°C for 3 hours in atmospheric air, and at 850°C for 40 minutes in atmospheric air. After oxidation, the material was naturally cooled and vibrated and sieved.

[0052] Place the alloy raw materials into a crucible of a vacuum induction melting furnace with a stirring device. After evacuating to 10Pa, heat it to 700℃ and keep it warm for 0.5h to fully melt it. Lower the melt temperature to 570-590℃, insert the stirring head below the liquid surface, and stir at a constant speed of 500r / min.

[0053] Add SiC to the central vortex of the aluminum alloy melt through the secondary feeding device. After the addition of silicon carbide is complete, evacuate to 10 Pa, increase the speed to 800 rpm, and continue stirring at 570-580 ° C for 1.5 hours.

[0054] Reduce the stirring speed to 200 r / min and raise the temperature of the aluminum-based composite melt to 700°C. Maintain a vacuum at 5-10 Pa and hold for 15 minutes. Stop stirring and remove the stirring head. Raise the temperature of the aluminum-based composite melt to 730°C. Gravity casting is used to produce an aluminum-based composite ingot, and pressure-regulated casting is used to prepare an aluminum-based composite brake disc.

[0055] The microstructure of the aluminum-based composite prepared in this embodiment is as follows: Figure 1 As shown, the characteristics of the reinforcing phase in the primary aluminum phase are as follows Figure 2 As shown. SiC is evenly distributed without obvious agglomeration. Strengthening phases such as silicon carbide, eutectic Si, Al3CuNi and AlSi(FeMn)CuNi form a network strengthening structure. The primary aluminum is synergistically strengthened by submicron-scale SiC, AlSiZr and AlSiCrMn nano-precipitates. The material has a room temperature tensile strength of 300MPa and a tensile strength of 205MPa at 300℃. In the thermal fatigue test, it showed excellent thermal fatigue resistance. After 700 cycles at 30℃~300℃, the prefabricated notch still did not produce obvious thermal fatigue cracks, and the hardness did not show obvious decline after 900 thermal cycles. Figure 3 The prepared aluminum-based composite brake disc was subjected to a 1:1 bench test, braking from 100 km / h to 5 km / h at a deceleration of 0.4 g, for a total of 15 braking times. Figure 4 As shown in the figure, the friction coefficient does not decline significantly when the temperature rises to 258℃, and remains stable at 0.3-0.4.

[0056] The above description is merely an embodiment of the present application and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the protection scope of the present 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 a SiC particle reinforcement with a mass fraction of 15% to 25%. The SiC particle reinforcement is a mixture of micron-sized particles and submicron-sized particles. The particle size of the micron-sized particles is 10 to 100 μm, and the particle size of the submicron-sized particles is 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.

2. The heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material according to claim 1, characterized in that: The SiC particle reinforcement is pre-oxidized and its surface is covered with an oxide layer. The thickness of the oxide layer on the surface of the micron-sized particles is different from that on the surface of the submicron-sized particles.

3. The heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material according to claim 2, characterized in that: The thickness of the oxide layer on the surface of micron-sized particles is greater than that on the surface of submicron-sized particles.

4. The heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material according to claim 3, characterized in that: The composition of the aluminum alloy matrix, based on the mass fraction of the aluminum alloy matrix as 100%, the mass percentage of each element is: 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 is Al and unavoidable impurities.

5. The heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material according to claim 4, characterized in that: The aluminum alloy matrix is a hypoeutectic aluminum-silicon alloy, micron-sized particles are distributed in the eutectic structure, and submicron-sized particles are distributed in the eutectic structure and the primary aluminum phase.

6. The heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material according to claim 5, characterized in that: The composite material includes a primary aluminum phase and a micron-scale network reinforcement structure. The network reinforcement structure includes 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 the volume percentage in the composite structure is ≥4%. The room temperature nanohardness value is 6-12 GPa, and the nanohardness value at 350°C is 4-8 GPa.

7. The heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material according to claim 6, characterized in that: The intermetallic compound strengthening phase includes Al3CuNi, Al3Ni, Al7Cu4Ni, and AlSi(FeMn)CuNi.

8. The heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material according to claim 6, characterized in that: The tensile strength of the aluminum-based composite material at room temperature is not less than 300 MPa, the tensile strength at 300°C is not less than 205 MPa, and the hardness is increased by 0-10% after 900 thermal mismatch strengthening cycles at 30°C-300°C.

9. The method for preparing the heat-resistant, cycle-resistant, and wear-resistant aluminum-based composite material according to claim 8, characterized in that: Prepare aluminum alloy raw materials according to the composition ratio and heat to melt. After pre-treating the silicon carbide particles, the particles are added into the melt and stirred to obtain an aluminum-based composite melt, and the aluminum-based composite melt is poured to obtain a silicon carbide aluminum-based composite material.

10. The preparation method according to claim 9, characterized in that The pretreatment includes pickling, ball milling, screening and oxidation. The oxidation process of micron-sized particles is oxidation at 900-1200° C. for 2-6 hours, and the oxidation process of submicron-sized particles is oxidation at 700-900° C. for 0.5-2 hours.

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