A ball milling layer-by-layer adhesion coating method for gradient coating on the surface of a wheel hub

Abstract

The present invention discloses a ball-milling layer-by-layer adhesion coating method for a gradient coating on the surface of a wheel hub. The aluminum alloy wheel hub is fixed in a ball-milling tank, and mixed powders of AlxFeNiSiTi high-entropy alloy + 6061 aluminum alloy with different volume fraction ratios are sequentially added in the ball-milling tank at different time periods. The stainless steel tank is tightly sealed and evacuated, and high-purity argon gas is introduced. The mixed powders are gradually mixed evenly under the impact between the stainless steel tank and the stainless steel grinding balls. During the ball-milling process, the mixed powders undergo cold welding under the impact between the stainless steel grinding balls and the surface of the wheel hub, and are adhered layer by layer on the surface of the aluminum alloy wheel hub, forming a gradient composite surface layer with different volume ratios of AlxFeNiSiTi high-entropy alloy + 6061 aluminum alloy on the surface of the aluminum alloy wheel hub. During this process, ultrasonic vibration is used to assist the high-frequency impact of the stainless steel balls on the surface of the coating to eliminate the pores in the coating, and deposition is carried out layer by layer in this way. Finally, diffusion sintering is carried out at an appropriate temperature, and the sintered coating is more dense, with good bonding of the particles and good bonding with the surface of the wheel hub.

Description

Technical Field

[0001] The present invention relates to the field of wheel hub coating, and specifically to a ball milling layer-by-layer adhesion coating method for a gradient coating on the surface of a wheel hub. Background Art

[0002] With the development of the times and the market demand, steel wheel hubs have been gradually replaced by aluminum alloy wheel hubs. The demand for low carbon and the concept of fashion and beauty, including the high strength, low density and good heat dissipation of aluminum alloy wheel hubs themselves, make them have extremely important value and prospects in the market. However, aluminum alloy wheel hubs have lower hardness than steel wheel hubs, and their corrosion resistance and impact resistance are relatively poor. Therefore, various defects inevitably appear on the surface of aluminum alloy wheel hubs during both processing and actual use. Surface treatment for the problems of low hardness and corrosion resistance on its surface is very important for improving the performance and lifespan of aluminum alloy wheel hubs.

[0003] Currently, the main method for surface strengthening of automobile wheel hubs is the wheel hub vacuum coating process. Chinese Patent Application No. CN110791738A discloses a vacuum magnetron sputtering ion coating process for wheel hubs. This process includes selecting silicon dioxide powder and binder as the initial target material, placing it in an oven to refine the target material; polishing the wheel hub with emery and brown fused alumina grinding stones; placing the polished aluminum alloy wheel hub in a vacuum magnetron sputtering coating machine for coating. The silicon dioxide used in this process has low cost, and the vacuum magnetron sputtering ion coating makes the silicon mold have good adhesion, but the utilization rate of the vacuum coating target is low and the cost is high.

[0004] Chinese Patent Application No. CN112593225A discloses a process method for preparing a high-hardness and corrosion-resistant wheel hub coating; this process includes: preparing AlxFeNiSiTi high-entropy alloy powder; mixing the AlxFeNiSiTi high-entropy alloy powder with stainless steel shot in a certain proportion, heating it to a predetermined temperature after mixing evenly; using inert gas to spray the AlxFeNiSiTi high-entropy alloy powder and stainless steel shot onto the surface of the wheel hub, and evenly attaching the AlxFeNiSiTi high-entropy alloy powder to the surface of the wheel hub to form a coating as the nozzle moves. This process mainly applies the AlxFeNiSiTi high-entropy alloy with good comprehensive performance to the aluminum alloy wheel hub coating, and can change the content of Al in the high-entropy alloy to effectively improve the hardness and corrosion resistance of the wheel hub surface. However, the density of this coating is not high, and there are pore defects in the coating formed by spraying with stainless steel shot. Therefore, a ball milling layer-by-layer adhesion coating method for a gradient coating on the surface of a wheel hub is provided. Summary of the Invention

[0005] The purpose of the present invention is to address the deficiencies of the prior art and provide a ball milling layer-by-layer adhesion coating method for a gradient coating on the surface of a wheel hub to solve the problems raised in the above background art.

[0006] To achieve the above object, the present invention provides the following technical solutions: A ball milling layer-by-layer adhesion coating method for a gradient coating on the surface of a wheel hub, and the specific steps are as follows:

[0007] S01. Prepare the materials required for the gradient coating: 6061 aluminum alloy powder, prepare a mixture powder of AlxFeNiSiTi high-entropy alloy powder with different volume fractions + 6061 aluminum alloy;

[0008] S02. Ultrasonically clean the wheel hub in absolute ethanol, and then dry it to avoid the influence of excess impurities on the composite material;

[0009] S03. Place the wheel hub at the bottom layer, add 6061 aluminum alloy powder, cover the surface of the wheel hub with stainless steel balls, tightly seal the stainless steel tank, evacuate it, and introduce high-purity argon gas for protection; The 6061 aluminum alloy powder undergoes cold welding layer by layer under the impact of the stainless steel balls and the surface of the wheel hub, and adheres to the surface of the wheel hub to form a matrix deposition layer with good bonding to the surface of the aluminum alloy wheel hub;

[0010] S04. Adopt the ball milling layer-by-layer adhesion technology, add a mixture powder of 25 vol.% AlxFeNiSiTi high-entropy alloy powder + 6061 aluminum alloy, tightly seal the stainless steel tank, evacuate it, and introduce high-purity argon gas for protection; The two mixture powders are continuously impacted and ground between the stainless steel balls and the ball milling tank, and are uniformly mixed under the impact of the stainless steel balls with the stainless steel tank and between the stainless steel balls. The mixture powder adheres to the surface of the wheel hub layer by layer under the impact of the stainless steel balls and the surface of the wheel hub to form an AlxFeNiSiTi high-entropy alloy powder + 6061 aluminum alloy gradient composite coating;

[0011] S05. Eliminate the pores in the coating by ultrasonically vibrating the stainless steel balls to impact the surface of the coating, and achieve the densification of the composite coating and good bonding with the surface of the wheel hub;

[0012] S06. Adopt the ball milling layer-by-layer adhesion technology, add a mixture powder of 50 vol.% AlxFeNiSiTi high-entropy alloy powder + 6061 aluminum alloy; Repeat steps S04 and S05 to achieve the densification of the composite coating and good bonding with the surface of the wheel hub;

[0013] S07. Adopt the ball milling layer-by-layer adhesion technology, add a mixture powder of 25 vol.% AlxFeNiSiTi high-entropy alloy powder + 6061 aluminum alloy; Repeat steps S04 and S05 to achieve the densification of the composite coating and good bonding with the surface of the wheel hub;

[0014] S08. Heat-treat the coating on the hub surface, place it in a predetermined temperature, and keep it warm for a period of time; during the heating process, argon is introduced at one end of the tubular furnace and water is introduced at the other end to prevent the coating from oxidizing; realize the bonding of the sintered coating particles, make the composite coating dense and have good bonding with the hub surface.

[0015] As a preferred technical solution of the present invention, the range of x in the AlxFeNiSiTi high-entropy alloy powder is 0.2 - 1.0.

[0016] As a preferred technical solution of the present invention, the diameter of the AlxFeNiSiTi high-entropy alloy powder particles is 300 - 1000 mesh.

[0017] As a preferred technical solution of the present invention, the volume fraction of the AlxFeNiSiTi high-entropy alloy in the gradient coating mixture is 25 - 50 vol.%.

[0018] As a preferred technical solution of the present invention, the thickness of each material coating is 20 - 50 μm.

[0019] As a preferred technical solution of the present invention, the diameter of the stainless steel grinding balls in S03 is 5 - 10 mm.

[0020] As a preferred technical solution of the present invention, the ball milling time in S04 is 48 - 72 h, and the ball milling speed is 200 - 300 r / min.

[0021] As a preferred technical solution of the present invention, the ultrasonic frequency in S05 is 20 - 40 kHz, and the ultrasonic power is 300 - 500 W.

[0022] As a preferred technical solution of the present invention, the predetermined temperature in S08 is 300 - 400 °C.

[0023] As a preferred technical solution of the present invention, the heat preservation time in S08 is 2 - 4 h.

[0024] The beneficial effects of the present invention are:

[0025] 1. Using the AlxFeNiSiTi high-entropy alloy as the coating material, it itself has the advantages of high hardness, corrosion resistance and wear resistance. At the same time, the 6061 aluminum alloy powder can make the AlxFeNiSiTi high-entropy alloy coating have better adhesion to the aluminum alloy hub, and plays a positive role in improving the thermal stability of the high-entropy alloy. Compared with the SiC particles, the bonding interface formed by the 6061 aluminum alloy powder and the aluminum alloy hub is less likely to debond under load and can transfer the load more effectively;

[0026] 2. For different hubs and different usage scenarios, the proportion of Al element in the main material coating of the AlxFeNiSiTi high-entropy alloy can be adjusted to give full play to the "cocktail effect" of the high-entropy alloy, while ensuring that the hardness of the coating is stably within 900-1000 HV;

[0027] 3. The process of using ball milling to adhere the coating layer by layer can make the mixed powder of AlxFeNiSiTi high-entropy alloy powder + 6061 aluminum alloy powder be continuously impacted and ground between the stainless steel grinding balls and the ball milling tank, and be evenly mixed under the action of impact. After the composite coating deforms, breaks and peels off, it is cold-welded to the hub surface through the impact of the stainless steel balls on the hub surface, and adheres to the hub surface layer by layer, greatly improving the adhesion of the coating. And by using ultrasonic vibration, the mixed powder can be fully utilized to improve the density of the coating and reduce defects such as pores in the coating;

[0028] 4. For some surface defects generated during the processing of the hub, some surface defects can be repaired during the preparation of the coating, improving the surface smoothness of the hub;

[0029] After the coating is diffusion sintered, the dispersed particles can undergo molten diffusion, and the metallurgical bonding between the particles can further improve the strength of the coating, forming a dense protective layer. Brief Description of the Drawings

[0030] Figure 1 It is a flowchart of the ball milling adhesion coating method for the surface gradient coating of the high-entropy alloy hub of the present invention;

[0031] Figure 2 It is a schematic diagram of the principle of the ball milling of the high-entropy alloy coating of the present invention;

[0032] Figure 3 It is a schematic diagram of the principle of the ball milling of the high-entropy alloy single composite coating of the present invention;

[0033] Figure 4 It is a schematic diagram of the process of the high-entropy alloy gradient coating of the present invention;

[0034] Figure 5 It is a microscopic morphology diagram of 6061 Al powder of the present invention;

[0035] Figure 6 It is the microscopic morphology of the AlxFeNiSiTi + 6061Al tissue with different volume ratios of the present invention.

[0036] In the figure: ball milling tank 1, stainless steel grinding ball 2, aluminum alloy hub 3, hub fixing device 4, high-entropy alloy powder 5, aluminum powder 6, dense coating 7. Detailed Embodiments

[0037] The following elaborates on the preferred embodiments of the present invention in conjunction with the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making the scope of protection of the present invention more clearly defined.

[0038] Embodiment 1: Refer to Figure 1-4 , the present invention provides a technical solution: a ball milling layer-by-layer adhesion coating method for a gradient coating on the surface of a wheel hub, including the following steps:

[0039] S01. In a vacuum environment, configure coating materials: 25 vol.% AlxFeNiSiTi high-entropy alloy powder + 6061 aluminum alloy mixed powder; 50 vol.% AlxFeNiSiTi high-entropy alloy powder + 6061 aluminum alloy mixed powder; 25 vol.% AlxFeNiSiTi high-entropy alloy powder + 6061 aluminum alloy mixed powder (denoted as Material-1 / 2 / 3 respectively);

[0040] S02. Ultrasonically clean the wheel hub in anhydrous ethanol and then dry it to avoid the influence of excess impurities on the composite material;

[0041] S03. Place the aluminum alloy wheel hub 3 inside the stainless steel ball milling tank 1. The aluminum alloy wheel hub 3 is placed on the wheel hub fixing device 4 at the bottom layer. Place 6061 aluminum alloy powder and put 5 - 10 mm stainless steel grinding balls 2. Among them, 5 mm microspheres are covered close to the wheel hub surface, and larger diameter steel balls are placed around the microspheres. Fasten and seal the stainless steel ball milling tank 1, evacuate it, and introduce high-purity argon as protection. The ball milling time is 24 hours, and the ball milling speed is 200 r / min. Through ball milling, the 6061 aluminum alloy powder undergoes cold welding and adheres layer by layer to the wheel hub surface under the impact of the stainless steel grinding balls and the wheel hub surface, forming a matrix deposition layer with good bonding to the surface of the aluminum alloy wheel hub;

[0042] S04. Adopt the ball milling layer-by-layer adhesion technology. Put Material-1 into the stainless steel ball milling tank, fasten and seal the stainless steel ball milling tank 1, evacuate it, and introduce high-purity argon as protection; the ball milling time is 16 h, and the ball milling speed is 200 r / min. The two mixed powders are continuously impacted and ground between the stainless steel grinding balls and the ball milling tank. They are mixed evenly under the impact of the stainless steel grinding balls 2 and the stainless steel ball milling tank 1. Through ball milling, the mixed powders deform, break, and exfoliate, and undergo cold welding and adhere layer by layer to the surface of the aluminum alloy wheel hub 3 under the impact of the stainless steel grinding balls 2 and the surface of the aluminum alloy wheel hub 3 to form an AlxFeNiSiTi high-entropy alloy powder + 6061 aluminum alloy gradient composite coating, and the thickness of this coating is 30 μm;

[0043] S05. Use an ultrasonic vibration stainless steel ball to impact the coating surface at a high frequency. The ultrasonic frequency is 20 kHz and the ultrasonic power is 300 W. Eliminate the pores in the composite coating by this method to achieve the densification of the composite coating and good bonding with the hub surface.

[0044] S06. Adopt the ball milling layer-by-layer adhesion technology. Place Material-2 in the stainless steel ball milling tank 1. The ball milling process is the same as that in S04. Repeat the steps of S04 and S05 to achieve the densification of the Material-2 composite coating and good bonding with the hub surface.

[0045] S07. Adopt the ball milling layer-by-layer adhesion technology. Place Material-3 in the stainless steel ball milling tank 1. The ball milling process is the same as that in S04. Repeat the steps of S04 and S05 to achieve the densification of the Material-3 composite coating and good bonding with the hub surface.

[0046] S08. Put the hub with the obtained composite coating into a tube furnace at a preset temperature of 350 °C and keep it warm for 2 h. During the heating process, argon is introduced at one end of the tube furnace and water is introduced at the other end to prevent the coating from oxidation. The coating after diffusion sintering is more dense, and the particles are well bonded to the hub surface.

[0047] Example 2:

[0048] Take SEM pictures of the gradient composite coatings of AlxFeNiSiTi high-entropy alloy + 6061 aluminum alloy with different volume ratios obtained in Example 1. The experimental results are as follows Figure 5 shown (the microscopic morphology of 6061Al powder is used as a reference);

[0049] As Figure 6 shown; after ball milling layer-by-layer adhesion, the AlxFeNiSiTi high-entropy alloy + 6061 aluminum alloy composite coating is mixed more evenly, and the high-entropy alloy particles are distributed more evenly in the aluminum alloy particles. Among them, the morphology of 6061Al alloy powder is nearly spherical, while the high-entropy alloy powder presents irregular fragmentary shapes, which can be used as a composite material reinforcement to improve the densification of the gradient coating on the hub surface.

[0050] In summary, the gradient coating of the aluminum alloy wheel hub with impact resistance and corrosion and wear resistance includes a 6061 aluminum alloy matrix layer, a mixed layer of AlxFeNiSiTi high-entropy alloy and 6061Al with different proportions. Each coating jointly constitutes the gradient coating on the surface of the wheel hub, and the particles between the coatings are all metallurgically bonded; the high-entropy alloy coating after diffusion sintering is denser and has higher strength; the high-entropy alloy + 6061 aluminum alloy mixed coating has good strength and toughness and has good impact resistance; the addition of the 6061 aluminum alloy matrix layer enables the high-entropy alloy mixed coating to better adhere to and transfer external loads to the aluminum alloy wheel hub, resulting in good bonding between the coating and the surface of the wheel hub; the design of the gradient material can promote better bonding between the coatings and between the coating and the surface of the wheel hub.

[0051] The above embodiments only represent several implementation modes of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. A ball milling layer-by-layer adhesion coating method for the surface gradient coating of a wheel hub, characterized in that: The specific steps are as follows: S01. Prepare the materials required for the gradient coating: Prepare 6061 aluminum alloy powder, and prepare a mixed powder of AlxFeNiSiTi high-entropy alloy powder with different volume fractions + 6061 aluminum alloy. The diameter of the AlxFeNiSiTi high-entropy alloy powder particles is 300 - 1000 mesh; S02. Ultrasonically clean the wheel hub in absolute ethanol, and then dry it to avoid the influence of excess impurities on the composite material; S03. Place the wheel hub at the bottom layer, add 6061 aluminum alloy powder, cover the surface of the wheel hub with stainless steel balls with a diameter of 5 - 10 mm, fasten and seal the stainless steel can, evacuate it, and introduce high-purity argon as protection; The 6061 aluminum alloy powder adheres layer by layer to the surface of the wheel hub by cold welding under the impact of the stainless steel balls and the surface of the wheel hub, forming a matrix deposition layer with good bonding to the surface of the aluminum alloy wheel hub; S04. Adhere layer by layer by ball milling, add a mixed powder of 25 vol.% AlxFeNiSiTi high-entropy alloy powder + 6061 aluminum alloy, fasten and seal the stainless steel can, evacuate it, and introduce high-purity argon as protection; The two mixed powders are continuously impacted and ground between the stainless steel balls and the ball milling can, and are evenly mixed under the impact of the stainless steel balls and the stainless steel can and between the stainless steel balls. The mixed powder adheres layer by layer to the surface of the wheel hub under the impact of the stainless steel balls and the surface of the wheel hub to form an AlxFeNiSiTi high-entropy alloy powder + 6061 aluminum alloy gradient composite coating; S05. Eliminate the pores in the coating by ultrasonically vibrating the stainless steel balls to impact the surface of the coating at high frequency, and achieve the densification of the composite coating and good bonding to the surface of the wheel hub; S06. Adhere layer by layer by ball milling, add a mixed powder of 50 vol.% AlxFeNiSiTi high-entropy alloy powder + 6061 aluminum alloy; Repeat steps S04 and S05 to achieve the densification of the composite coating and good bonding to the surface of the wheel hub; S07. Adhere layer by layer by ball milling, add a mixed powder of 25 vol.% AlxFeNiSiTi high-entropy alloy powder + 6061 aluminum alloy; Repeat steps S04 and S05 to achieve the densification of the composite coating and good bonding to the surface of the wheel hub; S08. Heat-treat the coating on the surface of the wheel hub, put it into a predetermined temperature, and the predetermined temperature is 300 - 400 °C, and keep it warm for a period of time; During the heating process, argon is introduced at one end of the tube furnace and water is introduced at the other end to avoid oxidation of the coating; Realize the bonding of the sintered coating particles, the densification of the composite coating and good bonding to the surface of the wheel hub.

2. The ball milling layer-by-layer adhesion coating method for the surface gradient coating of a wheel hub according to claim 1, wherein: The range of x in the AlxFeNiSiTi high-entropy alloy powder is 0.2 - 1.

0.

3. A ball milling layer-by-layer adhesion coating method for a gradient coating on the surface of a wheel hub according to claim 1, characterized in that: The thickness of each material coating is 20 - 50 μm.

4. A ball milling layer-by-layer adhesion coating method for a gradient coating on the surface of a wheel hub, characterized in that: The ball milling time in S04 is 48 - 72 h, and the ball milling speed is 200 - 300 r / min.

5. A ball milling layer-by-layer adhesion coating method for a gradient coating on the surface of a wheel hub, characterized in that: The ultrasonic frequency in S05 is 20 - 40 kHz, and the ultrasonic power is 300 - 500 W.

6. A ball milling layer-by-layer adhesion coating method for a gradient coating on the surface of a wheel hub, characterized in that: The heat preservation time in S08 is 2 - 4 h.

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