Method for multi-system laser cleaning and texturing of magnesium alloy matrix surface

Abstract

The invention discloses a method for multi-system laser cleaning and texturing of the surface of a magnesium alloy matrix, and relates to the technical field of laser cleaning, the method comprises the following steps: combining continuous laser and pulse laser to obtain multi-system combined laser; according to a preset scanning speed and a first preset scanning strategy, the coating on the surface of the magnesium alloy matrix is scanned through multi-system beam combining laser, and the coating on the surface of the magnesium alloy matrix is removed; and after the coating is removed, the first preset scanning strategy is adjusted to be a second preset scanning strategy, and according to a multi-system excitation direct radiation method, the surface of the magnesium alloy matrix with the coating removed is scanned through multi-system beam combining laser, and the texture layer is obtained. On the basis of keeping high cleaning efficiency, the substrate can be prevented from being ablated and damaged, and the texture layer can be formed on the surface of the substrate.

Description

Technical Field

[0001] The present application relates to the technical field of laser cleaning, and in particular to a method for multi-system laser cleaning and texturing of the surface of a magnesium alloy substrate. Background Art

[0002] Magnesium alloy substrates are considered to be typical and important lightweight alloys used in future aerospace applications. Research on efficient, convenient and environmentally friendly magnesium alloy surface coating removal technology is crucial to its application and development. Surface texture refers to the surface structure at the micron and nanometer scale. Micro-nanostructuring of traditional structural materials can give them special surface properties and expand their application prospects as new functional materials.

[0003] Researchers have found that laser cleaning technology is particularly suitable for metal materials such as magnesium alloys, aluminum alloys and titanium alloys. This technology can not only effectively remove coatings such as surface paint, but also form a regular microstructure on the surface of the substrate after cleaning, showing a surface modification effect. Tian et al. (Tian Z, Lei Z, Chen X, et al. Evaluation of laser cleaning for defouling of marine biofilm contamination on aluminum Alloys [J]. Applied Surface Science, 2020, 499: 144060.) When laser cleaning marine biofilm contamination on the surface of aluminum alloy substrates, while removing surface pollutants, it was seen that a nanostructured layer composed of amorphous nanocrystalline phases was formed on the surface of the aluminum alloy after cleaning. This nanostructured layer has great potential in anti-adhesion, anti-fouling and anti-corrosion. Li et al. (Li Z, Zhang D, Su X, et al. Removal mechanism of surface cleaning on TA15 titanium alloy using nanosecond pulsed Laser [J]. Optics & Laser Technology, 2021, 139: 106998.) found that when cleaning titanium alloy oxide film with specific laser parameters, the laser flux was 1.99 J / cm 2Under the condition of laser cleaning, the surface roughness decreases, the surface oxide film slightly melts and then oxidizes again. As the energy continues to increase, the oxide film is completely removed, and the laser impact force forms a periodic "ridge" structure on the surface. This microstructure has great advantages such as super hydrophobicity, anti-adhesion, anti-fouling and anti-corrosion. However, at present, the formation of micro-nanostructure on the surface of materials after laser cleaning is uncontrollable, the formed microstructure has poor continuity, and often presents an occasional state, especially for magnesium alloys, which are sensitive to heat and stress. It is very easy to cause matrix ablation damage during the cleaning process, and it is more difficult to control the formation of texture. Summary of the invention

[0004] The purpose of this application is to provide a method for multi-system laser cleaning and texturing of the surface of a magnesium alloy substrate to solve the problems of substrate ablation damage and poor continuity of the texture layer.

[0005] To achieve the above objectives, this application provides the following solutions:

[0006] In a first aspect, the present application provides a method for multi-system laser cleaning and texturing of a magnesium alloy substrate surface, comprising:

[0007] Combine continuous laser and pulse laser to obtain multi-system combined laser;

[0008] Scanning the coating on the surface of the magnesium alloy substrate using the multi-body combined beam laser according to a preset scanning speed and a first preset scanning strategy to remove the coating on the surface of the magnesium alloy substrate;

[0009] After removing the coating, the first preset scanning strategy is adjusted to a second preset scanning strategy, and according to a multi-body laser direct radiation method, the multi-body combined beam laser is used to scan the surface of the magnesium alloy substrate after removing the coating to obtain a texture layer.

[0010] Optionally, the wavelengths of the continuous laser and the pulse laser are both 1064 nm.

[0011] Optionally, scanning the surface coating of the magnesium alloy substrate by using the multi-system combined beam laser comprises:

[0012] According to the multi-body laser direct radiation method, the multi-body combined beam laser is used to scan the surface coating of the magnesium alloy substrate.

[0013] Optionally, the output power of the continuous laser is in the range of 90W-1000W, and the output power of the pulse laser is in the range of 30W-500W.

[0014] Optionally, the laser pulse width of the pulse laser is in the range of 50ns-500ns.

[0015] Optionally, the repetition frequency of the pulsed laser is in the range of 10 kHz-50 kHz.

[0016] Optionally, the shape of the light spot of the multi-body combined beam laser is circular, the diameter of the light spot ranges from 0.3 mm to 0.9 mm, and the scanning overlap rate is 5% to 15%.

[0017] Optionally, the scanning interval of the multi-system combined beam laser is in the range of 0.10mm-0.15mm, the preset scanning speed is in the range of 1500mm / s-3000mm / s, and the defocus amount is in the range of 125±3mm.

[0018] Optionally, the first preset scanning strategy is S-shaped reciprocating scanning.

[0019] Optionally, the second preset scanning strategy is linear scanning, circular scanning, square scanning, U-shaped scanning or bow-shaped scanning.

[0020] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0021] The present application discloses a method for cleaning and texturing the surface of a magnesium alloy substrate by using a multi-system laser. First, a continuous laser and a pulsed laser are combined to obtain a multi-system combined beam laser. Then, according to a preset scanning speed and a first preset scanning strategy, the coating on the surface of the magnesium alloy substrate is scanned by using a multi-system combined beam laser to remove the coating on the surface of the magnesium alloy substrate. Finally, after removing the coating, the first preset scanning strategy is adjusted to a second preset scanning strategy, and according to a multi-system laser direct radiation method, the surface of the magnesium alloy substrate after the coating is removed is scanned by using a multi-system combined beam laser to obtain a texture layer. The present application adopts a high-power continuous laser + a low-power pulsed laser to clean the coating. On the basis of maintaining a high cleaning efficiency, it can not only avoid substrate ablation damage, but also form a texture layer on the substrate surface by controlling the scanning strategy. Forming a texture layer on the surface by laser cleaning technology has the advantages of efficient and damage-free cleaning, and by forming a texture layer on the substrate surface, the clean substrate is given hydrophobic, hydrophilic, energy storage, wear-resistant and other functions, making the substrate surface more multifunctional and meeting the needs of subsequent use. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1A schematic flow chart of a method for multi-system laser cleaning and texturing of a magnesium alloy substrate surface provided in one embodiment of the present application;

[0024] Figure 2 It is a schematic diagram of the linear scanning strategy;

[0025] Figure 3 It is a schematic diagram of the circular scanning strategy;

[0026] Figure 4 It is a schematic diagram of the square scanning strategy;

[0027] Figure 5 This is a schematic diagram of the U-shaped scanning strategy;

[0028] Figure 6 It is a schematic diagram of the bow-shaped scanning strategy;

[0029] Figure 7 Schematic diagram of the original three-dimensional morphology of AZ31B magnesium alloy;

[0030] Figure 8 This is a schematic diagram of the three-dimensional morphology of AZ31B magnesium alloy after scanning using a linear scanning strategy;

[0031] Fig. 9 The schematic diagram of the three-dimensional morphology of AZ31B magnesium alloy after scanning using the circular scanning strategy;

[0032] Fig.10 The schematic diagram of the three-dimensional morphology of AZ31B magnesium alloy after scanning using the square scanning strategy;

[0033] Fig.11 The schematic diagram of the three-dimensional morphology of AZ31B magnesium alloy after scanning using the U-shaped scanning strategy;

[0034] Fig.12 The schematic diagram of the three-dimensional morphology of AZ31B magnesium alloy after scanning using the bow-shaped scanning strategy;

[0035] Fig.13 This is a global schematic diagram of the SEM micromorphology of the texture layer of AZ31B magnesium alloy after scanning using a circular scanning strategy;

[0036] Fig.14 The first partial schematic diagram of the texture scanning electron microscope microstructure of AZ31B magnesium alloy after scanning using a circular scanning strategy;

[0037] Fig.15 The second partial schematic diagram of the texture scanning electron microscope microstructure of AZ31B magnesium alloy after scanning using the circular scanning strategy;

[0038] Fig.16This is a global schematic diagram of the texture SEM microstructure of AZ31B magnesium alloy after scanning using a square scanning strategy;

[0039] Fig.17 The first partial schematic diagram of the texture scanning electron microscope micromorphology of AZ31B magnesium alloy after scanning using the square scanning strategy;

[0040] Fig.18 The second partial schematic diagram of the texture scanning electron microscope microstructure of AZ31B magnesium alloy after scanning using the square scanning strategy;

[0041] Fig.19 This is a global schematic diagram of the texture scanning electron microscope microstructure of AZ31B magnesium alloy after scanning using the U-shaped scanning strategy;

[0042] Fig. 20 The first partial schematic diagram of the texture scanning electron microscope microstructure of AZ31B magnesium alloy after scanning using the U-shaped scanning strategy;

[0043] Fig.21 This is the second partial schematic diagram of the texture scanning electron microscope micromorphology of AZ31B magnesium alloy after scanning using the U-shaped scanning strategy. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0045] The purpose of this application is to provide a method for multi-system laser cleaning and texturing of the surface of a magnesium alloy substrate, aiming to avoid substrate ablation damage while maintaining a high cleaning efficiency and forming a texture layer on the substrate surface.

[0046] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0047] In an exemplary embodiment, Figure 1 As shown, the method for multi-system laser cleaning and texturing of the surface of a magnesium alloy substrate in this embodiment includes:

[0048] Step 1: Combine the continuous laser and the pulsed laser to obtain a multi-system combined beam laser.

[0049] Step 2: Scan the coating on the surface of the magnesium alloy substrate using a multi-body combined beam laser according to a preset scanning speed and a first preset scanning strategy to remove the coating on the surface of the magnesium alloy substrate.

[0050] Among them, the coating includes paint.

[0051] Step 3: After removing the coating, the first preset scanning strategy is adjusted to the second preset scanning strategy, and according to the multi-body laser direct radiation method, the surface of the magnesium alloy substrate after removing the coating is scanned using a multi-body combined beam laser to obtain a texture layer.

[0052] As an optional implementation, the wavelengths of the continuous laser and the pulse laser are both 1064 nm.

[0053] As an optional implementation, a multi-system combined beam laser is used to scan the surface coating of the magnesium alloy substrate, including:

[0054] According to the multi-body laser direct radiation method, the surface coating of the magnesium alloy substrate is scanned by using a multi-body combined beam laser.

[0055] As an optional implementation, the output power of the continuous laser is in the range of 90W-1000W, and the output power of the pulse laser is in the range of 30W-500W.

[0056] As an optional implementation, the laser pulse width of the pulse laser is in the range of 50ns-500ns.

[0057] As an optional implementation, the repetition frequency of the pulse laser is in the range of 10 kHz-50 kHz.

[0058] As an optional implementation, the shape of the light spot of the multi-body combined beam laser is circular, the diameter of the light spot ranges from 0.3 mm to 0.9 mm, and the scanning overlap rate is 5% to 15%.

[0059] As an optional implementation, the scanning interval of the multi-system combined beam laser is in the range of 0.10mm-0.15mm, the preset scanning speed is in the range of 1500mm / s-3000mm / s, and the defocus range is 125±3mm.

[0060] As an optional implementation, the first preset scanning strategy is S-shaped reciprocating scanning.

[0061] As an optional implementation, the second preset scanning strategy is linear scanning, circular scanning, square scanning, U-shaped scanning or bow-shaped scanning.

[0062] Specifically, when the second preset scanning strategy is adopted, laser ablation damage to the substrate during the texturing process is avoided by reducing the power of the continuous laser in the multi-body combined beam laser and / or increasing the preset scanning speed.

[0063] Each second preset scanning strategy is as follows Figure 2-Figure 6 shown.

[0064] Furthermore, the method of the present application is also used to remove paint and texture AZ31B magnesium alloy. Taking the multi-system combined beam laser under one parameter combination as an example, the specific process includes:

[0065] Step 1: Select a continuous laser with a wavelength of 1064nm and an output power of 90W and a pulsed laser with a wavelength of 1064nm, an output power of 45W, a repetition frequency of 25kHz, and a laser pulse width of 100ns for beam combination to obtain a multi-system beam combination laser.

[0066] Step 2: Adjust the diameter of the circular spot of the multi-system combined beam laser to 0.4mm.

[0067] Step 3: Select the preset scanning speed of 2700mm / s, scanning spacing of 0.12mm, and scanning overlap rate of 5%.

[0068] Step 4: Focus the multi-system combined beam laser on the paint on the surface of the magnesium alloy with a defocus of 125mm, and scan it back and forth in an S shape until the paint is completely removed.

[0069] Step 5: Adjust the scanning strategy to U-shaped scanning, scan back and forth once, and form a U-shaped texture layer on the surface of the magnesium alloy substrate.

[0070] Similarly, after the paint is completely removed, different laser scanning strategies such as linear, circular, square, and bow-shaped texture layers can be formed on the substrate surface to form linear texture layers, circular texture layers, square texture layers, and bow-shaped texture layers.

[0071] like Figure 7 As shown, the original surface roughness of AZ31B magnesium alloy is low, with a root mean square height of 1.383 μm and a maximum height of 15.694 μm, at which point the surface roughness is minimum.

[0072] Figure 8-Figure 12 The three-dimensional morphology schematic diagrams of AZ31B magnesium alloy after scanning using different scanning strategies are observed. It is observed that under the multi-system combined beam laser under the set parameter combination, the paint on the substrate surface can be effectively removed. At the same time, five different surface morphologies are formed on the substrate surface, including linear plowing grooves, circular rings, squares, U-shaped inlays, and bow-shaped remelting.

[0073] Figure 13-Figure 21The texture scanning electron microscope micromorphology images of AZ31B magnesium alloy after scanning using different scanning strategies are shown in Figure 2. Figure 13-Figure 15 It is a ring-shaped scanning strategy. It is observed that the surface remelted layer is distributed in a circular shape, and the closer to the center of the sample, the smaller the diameter of the ring. Figure 16-Figure 18 The square scanning strategy adopts a cleaning method of first horizontal scanning and then vertical scanning. It is observed that the gaps left by the intersection of horizontal scanning and vertical scanning will appear as square structures, and are evenly distributed on the surface of the remelting layer. Figure 19-21 It is a U-shaped scanning strategy, and it is observed that the surface of the substrate is in a U-shaped shape after cleaning.

[0074] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0075] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A method for cleaning and texturing the surface of a magnesium alloy substrate by multi-system laser, characterized in that: The multi-system laser cleaning and texturing method for the surface of a magnesium alloy substrate comprises: Combine continuous laser and pulse laser to obtain multi-system combined laser; Scanning the coating on the surface of the magnesium alloy substrate using the multi-body combined beam laser according to a preset scanning speed and a first preset scanning strategy to remove the coating on the surface of the magnesium alloy substrate; After removing the coating, the first preset scanning strategy is adjusted to a second preset scanning strategy, and according to a multi-body laser direct radiation method, the multi-body combined beam laser is used to scan the surface of the magnesium alloy substrate after removing the coating to obtain a texture layer.

2. The method for cleaning and texturing the surface of a magnesium alloy substrate by multi-system laser according to claim 1, characterized in that: The wavelengths of the continuous laser and the pulse laser are both 1064 nm.

3. The method for cleaning and texturing the surface of a magnesium alloy substrate by multi-system laser according to claim 1, characterized in that: Scanning the surface coating of the magnesium alloy substrate by using the multi-system combined beam laser comprises: According to the multi-body laser direct radiation method, the multi-body combined beam laser is used to scan the surface coating of the magnesium alloy substrate.

4. The method for cleaning and texturing the surface of a magnesium alloy substrate by multi-system laser according to claim 1, characterized in that: The output power of the continuous laser is in the range of 90W-1000W, and the output power of the pulse laser is in the range of 30W-500W.

5. The method for cleaning and texturing the surface of a magnesium alloy substrate by multi-system laser according to claim 1, characterized in that: The laser pulse width of the pulse laser is in the range of 50ns-500ns.

6. The method for cleaning and texturing the surface of a magnesium alloy substrate by multi-system laser according to claim 1, characterized in that: The repetition frequency of the pulse laser is in the range of 10 kHz-50 kHz.

7. The method for cleaning and texturing the surface of a magnesium alloy substrate by multi-system laser according to claim 1, characterized in that: The shape of the light spot of the multi-system combined beam laser is circular, the diameter of the light spot ranges from 0.3 mm to 0.9 mm, and the scanning overlap rate is 5% to 15%.

8. The method for cleaning and texturing the surface of a magnesium alloy substrate by multi-system laser according to claim 1, characterized in that: The scanning interval of the multi-system combined beam laser is in the range of 0.10mm-0.15mm, the preset scanning speed is in the range of 1500mm / s-3000mm / s, and the defocus amount is in the range of 125±3mm.

9. The method for cleaning and texturing the surface of a magnesium alloy substrate by multi-system laser according to claim 1, characterized in that: The first preset scanning strategy is S-shaped reciprocating scanning.

10. The method for cleaning and texturing the surface of a magnesium alloy substrate by multi-system laser according to claim 1, characterized in that: The second preset scanning strategy is linear scanning, circular scanning, square scanning, U-shaped scanning or bow-shaped scanning.

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