High-strength heat-resistant automotive aluminum-based composite material brake disc and preparation method thereof

Abstract

The invention discloses a high-strength heat-resistant automotive aluminum-based composite material brake disc and a preparation method thereof. The method comprises the steps that after ceramic reinforced particles and aluminum-based powder are evenly mixed, cold isostatic pressing and hot isostatic pressing sintering are sequentially conducted, and an aluminum-based composite material ingot blank is obtained; the aluminum matrix composite ingot blank is subjected to hot extrusion deformation to obtain an extruded round ingot, and then the round ingot is segmented and upset through free forging to obtain a forged blank; and carrying out hot-pressing die forging on the forged blank, air-cooling to room temperature after forging, and then machining to obtain the high-strength steel. According to the method, through the hot extrusion and forging processes, the technical effects of grain refinement and compact tissue of the material are achieved while an oxidation film introduced by aluminum alloy powder of the powder metallurgy material is crushed, and the macroscopic defects of the material are remarkably reduced. According to the brake disc obtained through the method, on the premise that the light weight of the brake disc is guaranteed, the mechanical strength, toughness, heat resistance and wear resistance of the brake disc are greatly improved, and therefore the technical problems that in the prior art, the brake disc is softened seriously under the high-temperature condition and is prone to cracking are effectively solved.

Description

Technical Field

[0001] The invention relates to a method for preparing a brake disc, in particular to a high-strength and heat-resistant aluminum-based composite brake disc for vehicles and a method for preparing the same, and belongs to the technical field of brake discs. Background Art

[0002] With the rapid development of the transportation industry, energy shortage has become an important challenge it faces, and energy conservation has become one of the key goals of the industry's development. For automobiles, the main energy-saving measures include two aspects: one is to accelerate the promotion of new energy vehicles, and the other is to improve energy efficiency by reducing the weight of the vehicle itself. Using lightweight aluminum-based composite materials to replace the currently widely used traditional materials such as cast iron to manufacture brake discs can significantly reduce the weight of the vehicle and has broad application prospects. In addition, aluminum-based composite brake discs have the advantages of light weight, excellent friction and wear performance, good thermal conductivity and thermal fatigue resistance, and show strong competitiveness in the field of automotive brake discs.

[0003] Brake discs experience complex working conditions such as high temperature, friction and vibration during operation. The toughness stability, oxidation resistance, wear resistance and thermal fatigue resistance of aluminum-based composite materials under high temperature environments are key issues restricting their application. Chinese patent (CN112780708A) "A solid brake disc made of aluminum-based composite materials for automobiles and its preparation method" discloses a SiC composite material prepared by anti-gravity casting. p / A356 aluminum-based composite brake disc, which can reduce weight by more than 40% compared to gray cast iron brake discs, but the A356 aluminum matrix softens severely under high temperature conditions, and the casting method is difficult to prepare fine-sized, high-strength, high-quality percentage SiC-reinforced aluminum-based composite brake discs, which limits the application of aluminum-based composite brake discs in new energy vehicles. Summary of the invention

[0004] In view of the problems existing in the prior art, the first purpose of the present invention is to provide a high-strength and heat-resistant aluminum-based composite brake disc for automobiles. Based on the synergy between ceramic reinforcement materials and aluminum-based materials, the brake disc greatly improves the mechanical strength, toughness, heat resistance and wear resistance of the brake disc while ensuring the low density and light weight of the brake disc, thereby effectively solving the technical problem of the brake disc being severely softened and easily cracked under high temperature conditions in the prior art.

[0005] The second object of the present invention is to provide a method for preparing a high-strength and heat-resistant aluminum-based composite brake disc for automobiles. The method uses hot extrusion and forging processes to break the oxide film on the surface of the material while also achieving the technical effects of grain refinement and dense structure of the material, significantly reducing the macroscopic defects of the material, effectively improving the strength and toughness of the brake disc, and improving the fatigue resistance of the brake disc during braking.

[0006] In order to achieve the above technical objectives, the present invention provides a method for preparing a high-strength and heat-resistant aluminum-based composite brake disc for vehicles, comprising: Step S1, after uniformly mixing the ceramic reinforcement particles and the aluminum-based powder, sequentially subjecting the mixture to cold isostatic pressing and hot isostatic pressing sintering to obtain an aluminum-based composite material ingot; Step S2, hot extruding and deforming the aluminum-based composite material ingot to obtain an extruded round ingot, and then dividing the round ingot and performing free forging and upsetting to obtain a forged blank; Step S3, hot-pressing the forged blank, air-cooling it to room temperature after forging, and then machining it to obtain the forged blank; The mass ratio of the ceramic reinforcement particles to the aluminum-based powder is 1:1.5-4.

[0007] The high temperature mechanical properties of the brake disc provided by the present invention are mainly based on the fine dispersed nano-Al in the aluminum-based alloy. 12 The synergistic effect between the (Fe,V)3Si heat-resistant phase and the ceramic reinforcement ensures that the material has excellent wear resistance and high mechanical strength. Therefore, the brake disc should be modified in strict accordance with the above steps. The replacement or deletion of any step may cause Al 12 The heat-resistant phase of (Fe,V)3Si changes, making it impossible to achieve the corresponding technical effect.

[0008] As a preferred solution, the ceramic reinforcing particles are at least one of SiC, BN, B4C and Al2O3, and the particle size range is 0.5~100μm.

[0009] As a preferred solution, the aluminum-based powder is an Al-Fe-V-Si alloy matrix.

[0010] As a preferred solution, the particle size range of the ceramic reinforcement particles is normally distributed.

[0011] As a preferred solution, the Al-Fe-V-Si alloy matrix is ​​one of FVS0611, FVS0812 and FVS1212.

[0012] As a preferred solution, the uniform mixing method is spheroidal graphite mixing, and the conditions are: rotation speed is 160 rpm, time is 1.5 h, and the ratio of balls to materials is 8~10:3~5.

[0013] As a preferred solution, the conditions for the cold isostatic pressing are: a pressure of 100 MPa to 150 MPa, and a holding time of 15 to 45 min.

[0014] As a preferred solution, the hot isostatic pressing sintering conditions are: at 2 ~ 3×10 -3Under the vacuum condition of 1.50 Pa, the temperature is raised from room temperature to 540~580℃ and kept for 3~5h, and the pressure is 80~120MPa.

[0015] As a preferred solution, the free forging process is: heating the divided round ingot to 450-530°C, keeping the temperature for 2-8 hours, and then performing upsetting.

[0016] As a preferred solution, the conditions for hot die forging are: the preheating temperature of the forging blank is 480-550°C, and the preheating temperature of the die is 300-450°C.

[0017] As a preferred solution, the machining includes perforating, deburring, grinding and polishing; and annealing treatment is required before the machining, and the conditions are: temperature of 440-480°C and time of 100-140 minutes.

[0018] The present invention also provides a high-strength and heat-resistant aluminum-based composite brake disc for vehicles, which is obtained by any of the preparation methods described above; the density of the aluminum-based composite brake disc is 2.80-3.2 g / cm 3 .

[0019] Compared with the prior art, the beneficial technical effects of the technical solution of the present invention are: 1) The aluminum-based composite brake disc provided by the present invention is based on the synergistic effect between the ceramic reinforcement material and the aluminum-based material. On the premise of ensuring the low density and light weight of the brake disc, the mechanical strength, toughness and heat and wear resistance of the brake disc are greatly improved, thereby effectively solving the technical problems of the brake disc being severely softened and easily cracked under high temperature conditions in the prior art; 2) The preparation method provided by the present invention achieves the technical effects of grain refinement and dense structure of the material while breaking the oxide film on the surface of the material through hot extrusion and forging processes, significantly reduces the macro defects of the material, effectively improves the toughness of the brake disc, and improves the fatigue resistance of the brake disc during the braking process; 3) In the technical solution provided by the present invention, the aluminum-based alloy of the brake disc mainly relies on fine dispersed nano-Al 12 (Fe,V)3Si heat-resistant phase is used to achieve high-temperature strengthening, and micron-level ceramic reinforcement materials are used to further improve its high-temperature mechanical properties and wear resistance, thus giving the brake disc the advantages of high room temperature and high-temperature strength, good toughness, good thermal stability, strong creep resistance, high stiffness, and low reinforcement phase coarsening rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A flow chart of the preparation process of the brake disc provided by the present invention; Figure 2This is the microstructure of 30% / SiC reinforced FVS0812 in Example 2 of the present invention. DETAILED DESCRIPTION

[0021] In order to facilitate the understanding of the present invention, the present invention will be described in more comprehensive and detailed manner in conjunction with the accompanying drawings and preferred embodiments of the specification. It should be noted that the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] The Al-Fe-V-Si alloy matrix used in the embodiments provided by the present invention is one of FVS0611, FVS0812 and FVS1212, and the specific chemical composition is shown in Table 1:

[0023] There is Al in the matrix of the above three aluminum alloy materials. 12 (Fe,V)3Si dispersed phase, within the appropriate temperature range, Al 12 The (Fe,V)3Si dispersed phase has good thermal stability.

[0024] Example 1 This embodiment provides a method for preparing an aluminum-based composite brake disc, comprising the following steps: S1: Mix 30% SiC particle powder and FVS0611 powder evenly, with a ball milling speed of 160rpm, a ball milling time of 1.5 h, and a ball-to-material ratio of 9:4. The mixed powder is pressed into a green body by cold isostatic pressing at a pressure of 100MPa~150MPa and a holding time of 30min. Then put it into a vacuum hot isostatic press for hot isostatic pressing, with a sintering temperature of 560℃, a holding temperature of 4h, and a pressure of 100 MPa. An aluminum-based composite ingot with a diameter of 300 mm and a height of 800 mm is obtained; S2: The aluminum-based composite material ingot is subjected to hot extrusion deformation at a hot extrusion temperature of 500°C, and an extruded round ingot with a diameter of 220 mm is obtained by extrusion; S3: cutting the aluminum-based composite material ingot into billets with a diameter of 220 mm and a height of 70 mm, heating the billets to 500° C., keeping the temperature for 4 hours, and upsetting the billets by free forging on a hydraulic press to obtain forging billets of a certain size; S4: preheating the aluminum-based composite forging to 520° C., preheating the die to 400° C., performing hot press die forging, and air cooling to room temperature after forging; S5: The die forging is subjected to annealing pretreatment at a temperature of 460°C for 120 min. Finally, a series of processes such as perforation, deburring, grinding and polishing are performed through machining to obtain an aluminum-based composite brake disc. The mechanical properties are shown in Table 2:

[0025] Example 2 This embodiment provides a method for preparing an aluminum-based composite brake disc, comprising the following steps: S1: Mix 30% SiC particle powder and FVS0812 powder evenly, with a ball milling speed of 160rpm, a ball milling time of 1.5 h, and a ball-to-material ratio of 9:4. The mixed powder is pressed into a green body by cold isostatic pressing at a pressure of 100MPa~150MPa and a holding time of 30min. Then put it into a vacuum hot isostatic press for hot isostatic pressing, with a sintering temperature of 560℃, a holding temperature of 4h, and a pressure of 100 MPa. An aluminum-based composite ingot with a diameter of 300 mm and a height of 800 mm is obtained; S2: The aluminum-based composite material ingot is subjected to hot extrusion deformation at a hot extrusion temperature of 500°C, and an extruded round ingot with a diameter of 220 mm is obtained by extrusion; S3: cutting the aluminum-based composite material ingot into billets with a diameter of 220 mm and a height of 70 mm, heating the billets to 500° C., keeping the temperature for 4 hours, and upsetting the billets by free forging on a hydraulic press to obtain forging billets of a certain size; S4: preheating the aluminum-based composite forging to 520° C., preheating the die to 400° C., performing hot press die forging, and air cooling to room temperature after forging; S5: The die forging is subjected to annealing pretreatment at a temperature of 460°C for 120 min. Finally, a series of processes such as perforation, deburring, grinding and polishing are performed by machining to obtain an aluminum-based composite brake disc. The mechanical properties are shown in Table 3:

[0026] Example 3 This embodiment provides a method for preparing an aluminum-based composite brake disc, comprising the following steps: S1: Mix 30% SiC particle powder and FVS1212 powder evenly, with a ball milling speed of 160rpm, a ball milling time of 1.5 h, and a ball-to-material ratio of 9:4. The mixed powder is pressed into a green body by cold isostatic pressing at a pressure of 100MPa~150MPa and a holding time of 30min. Then put it into a vacuum hot isostatic press for hot isostatic pressing, with a sintering temperature of 560℃, a holding temperature of 4h, and a pressure of 100 MPa. An aluminum-based composite ingot with a diameter of 300 mm and a height of 800 mm is obtained; S2: The aluminum-based composite material ingot is subjected to hot extrusion deformation at a hot extrusion temperature of 500°C, and an extruded round ingot with a diameter of 220 mm is obtained by extrusion; S3: cutting the aluminum-based composite material ingot into billets with a diameter of 220 mm and a height of 70 mm, heating the billets to 500° C., keeping the temperature for 4 hours, and upsetting the billets by free forging on a hydraulic press to obtain forging billets of a certain size; S4: preheating the aluminum-based composite forging to 520° C., preheating the die to 400° C., performing hot press die forging, and air cooling to room temperature after forging; S5: The die forging is subjected to annealing pretreatment at a temperature of 460°C for 120 min. Finally, a series of processes such as perforation, deburring, grinding and polishing are performed by machining to obtain an aluminum-based composite brake disc. The mechanical properties at room temperature are shown in Table 4:

[0027] Example 4 This embodiment provides a method for preparing an aluminum-based composite brake disc, comprising the following steps: S1: Mix SiC particle powder with a mass fraction of 40% and FVS0611 powder evenly, with a ball milling speed of 160rpm, a ball milling time of 1.5 h, and a ball-to-material ratio of 9:4. The mixed powder is pressed into a green body by cold isostatic pressing at a pressure of 100MPa~150MPa and a holding time of 30min. Then put it into a vacuum hot isostatic press for hot isostatic pressing, with a sintering temperature of 560℃, a holding temperature of 4h, and a pressure of 100 MPa. An aluminum-based composite ingot with a diameter of 300 mm and a height of 800 mm is obtained; S2: The aluminum-based composite material ingot is subjected to hot extrusion deformation at a hot extrusion temperature of 530°C, and an extruded round ingot with a diameter of 260 mm is obtained by extrusion; S3: cutting the aluminum-based composite material ingot into billets with a diameter of 260 mm and a height of 60 mm, heating the billets to 520° C., keeping the temperature for 6 hours, and upsetting the billets by free forging on a hydraulic press to obtain forging billets of a certain size; S4: preheating the aluminum-based composite forging to 530° C., preheating the die to 450° C., performing hot press die forging, and air cooling to room temperature after forging; S5: The die forging is subjected to annealing pretreatment at a temperature of 460°C for 120 min. Finally, a series of processes such as perforation, deburring, grinding and polishing are performed by machining to obtain an aluminum-based composite brake disc. The mechanical properties at room temperature are shown in Table 5:

[0028] Comparative Example This comparative example is exactly the same as Example 2, except that after the blank is hot-pressed and sintered to obtain a round cake-shaped blank of a certain size, it is directly die-forged, and the hot extrusion and upsetting steps are omitted. Its mechanical properties are shown in Table 6:

Claims

1. A method for preparing a high-strength and heat-resistant aluminum-based composite brake disc for a vehicle, characterized in that: include: Step S1, after uniformly mixing the ceramic reinforcement particles and the aluminum-based powder, sequentially subjecting the mixture to cold isostatic pressing and hot isostatic pressing sintering to obtain an aluminum-based composite material ingot; Step S2, hot extruding and deforming the aluminum-based composite material ingot to obtain an extruded round ingot, and then dividing the round ingot and performing free forging and upsetting to obtain a forged blank; Step S3, hot press die forging the forged blank, air cooling to room temperature after forging, and then machining to obtain; The mass ratio of the ceramic reinforcement particles to the aluminum-based powder is 1:1.5-4.

2. The method for preparing a high-strength and heat-resistant aluminum-based composite brake disc for vehicles according to claim 1, characterized in that: The ceramic reinforcement particles are at least one of SiC, BN, B4C and Al2O3, and the particle size range is 0.5-100 μm; the aluminum-based powder is an Al-Fe-V-Si alloy matrix.

3. The method for preparing a high-strength and heat-resistant aluminum-based composite brake disc for vehicles according to claim 2, characterized in that: The particle size range of the ceramic reinforcement particles is normally distributed; the Al-Fe-V-Si alloy matrix is ​​one of FVS0611, FVS0812 and FVS1212.

4. The method for preparing a high-strength and heat-resistant aluminum-based composite brake disc for vehicles according to claim 1, characterized in that: The uniform mixing method is spheroidal graphite mixing, and the conditions are: rotation speed is 160 rpm, time is 1.5 h, and the ratio of balls to materials is 8~10:3~5.

5. The method for preparing a high-strength and heat-resistant aluminum-based composite brake disc for vehicles according to claim 1, characterized in that: The cold isostatic pressing conditions are: pressure of 100 MPa to 150 MPa, and holding time of 15 to 45 min.

6. The method for preparing a high-strength and heat-resistant aluminum-based composite brake disc for vehicles according to claim 1, characterized in that: The hot isostatic pressing sintering conditions are: at 2 ~ 3×10 -3 Under the vacuum condition of 1.50 Pa, the temperature is raised from room temperature to 540~580℃ and kept for 3~5h, and the pressure is 80~120MPa.

7. The method for preparing a high-strength and heat-resistant aluminum-based composite brake disc for vehicles according to claim 1, characterized in that: The free forging process is as follows: heating the divided round ingot to 450-530° C., keeping the temperature for 2-8 hours, and then performing upsetting.

8. The method for preparing a high-strength and heat-resistant aluminum-based composite brake disc for vehicles according to claim 1, characterized in that: The conditions for hot die forging are: the preheating temperature of the forging blank is 480-550°C, and the preheating temperature of the die is 300-450°C.

9. The method for preparing a high-strength and heat-resistant aluminum-based composite brake disc for vehicles according to claim 1, characterized in that: The machining includes perforating, deburring, grinding and polishing; before the machining, annealing treatment is required, and the conditions are: temperature of 440-480° C. and time of 100-140 min.

10. A high-strength and heat-resistant aluminum-based composite brake disc for vehicles, characterized in that: Obtained by the preparation method according to any one of claims 1 to 9; the density of the aluminum-based composite brake disc is 2.80 to 3.2 g / cm 3 .

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